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Product User Manual for “Rapid Development Thunderstorms” _RDT

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Product User Manual for “Rapid Development Thunderstorms” _RDT Powered By Docstoc
					                                                              Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                              Issue:         2.2 Date:22    October
                               Product User Manual for “Rapid
                               Development    Thunderstorms” 2010
                               (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                              11_v2.2
                                                              Page:                            1/22




         Product User Manual for “Rapid
          Development Thunderstorms”
               (RDT-PGE11 v2.2)

                   SAF/NWC/CDOP/MFT/SCI/PUM/11, Issue 2, Rev. 2
                                      22 October 2010




           Applicable to SAFNWC/MSG version 2011




Prepared by Météo-France / Direction de la Prévision
                                                           Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                           Issue:         2.2 Date:22    October
                            Product User Manual for “Rapid
                            Development    Thunderstorms” 2010
                            (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                           11_v2.2
                                                           Page:                            2/22



                         REPORT SIGNATURE TABLE

  Function              Name                      Signature                     Date
                DPREVI/PI
Prepared by                                 Signed, F. Autones            22 October 2010
                METEO-FRANCE
                DPREVI/PI                   Signed, JM.
Reviewed by                                                               22 October 2010
                METEO-FRANCE                Moisselin
                Pilar Fernandez
Authorised by   SAFNWC Project                                            22 October 2010
                Manager
                                                            Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                            Issue:         2.2 Date:22    October
                             Product User Manual for “Rapid
                             Development    Thunderstorms” 2010
                             (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                            11_v2.2
                                                            Page:                            3/22



                        DOCUMENT CHANGE RECORD


Version         Date        Pages                  CHANGE(S)
              Document code SAF/NWC/CDOP/MFT/SCI/PUM/11
                                  SAF/NWC/CDOP/MFT/SCI/PUM/11: First
  1.3     19 November 2007    22
                                  published version (content derived from
                                  “Software User Manual for the PGE11 of the
                                  SAF NWC/MSG: Scientific Part”)
  2.0      01 October 2008                   New discrimination algorithm. And
                                             configuration file simplification
  2.1      01 October 2009
  2.2      22 October 2010               Use of NWP data for definition of region of
                                         interest, New tuning of discrimination scheme
                                         using NWP data guidance
                                                                                           Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                                           Issue:         2.2 Date:22    October
                                                  Product User Manual for “Rapid
                                                  Development    Thunderstorms” 2010
                                                  (RDT-PGE11 v2.2)               File:                 SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                                 11_v2.2
                                                                                 Page:                                                      4/22



Table of contents

1.     INTRODUCTION ...................................................................................................................6
1.1     SCOPE OF THE DOCUMENT .......................................................................................................6
1.2     SCOPE OF OTHER DOCUMENTS .................................................................................................6
1.3     SOFTWARE VERSION IDENTIFICATION .....................................................................................6
1.4     IMPROVEMENT FROM PREVIOUS VERSION ................................................................................6
1.5     DEFINITIONS, ACRONYMS AND ABBREVIATIONS .....................................................................7
1.6     REFERENCES ...........................................................................................................................8
   1.6.1    Applicable documents....................................................................................................8
   1.6.2    Reference documents .....................................................................................................8
2.     DESCRIPTION OF THE PRODUCT...................................................................................8
2.1     GOAL OF THE RDT PRODUCT ..................................................................................................8
2.2     OUTLINE OF THE ALGORITHM ..................................................................................................9
   2.2.1    The detection of cloud systems ......................................................................................9
   2.2.2    The tracking of cloud systems......................................................................................10
   2.2.3    The discrimination of convective objects.....................................................................10
2.3     DESCRIPTION OF THE OUTPUT ...............................................................................................12
3.     IMPLEMENTATION OF THE PRODUCT ......................................................................13

4.     INPUTS AND CONFIGURABLE PARAMETERS ..........................................................14
4.1     LIST OF INPUTS .....................................................................................................................14
   4.1.1     Mandatory inputs.........................................................................................................14
   4.1.2     Optional inputs ............................................................................................................15
4.2     CONFIGURABLE PARAMETERS ...............................................................................................17
5.     VALIDATION .......................................................................................................................20
5.1       SUMMARY OF VALIDATION RESULTS .....................................................................................20
5.2       KNOWN PROBLEMS AND LIMITATIONS ...................................................................................20
6.     EXAMPLE OF PRODUCT VISUALISATION.................................................................21
     6.1.1        Example of simple visualization tool...........................................................................21
                                                                                         Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                                         Issue:         2.2 Date:22    October
                                                 Product User Manual for “Rapid
                                                 Development    Thunderstorms” 2010
                                                 (RDT-PGE11 v2.2)               File:                SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                                11_v2.2
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List of Tables and Figures


Figure 1: RDT cell definition .............................................................................................................. 9
Figure 2: RDT objects before convective discrimination.................................................................. 11
Figure 3: RDT objects after convective discrimination..................................................................... 11
Figure 4: Example of product visualisation....................................................................................... 22
                                                                 Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                 Issue:         2.2 Date:22    October
                                  Product User Manual for “Rapid
                                  Development    Thunderstorms” 2010
                                  (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                 11_v2.2
                                                                 Page:                            6/22




1. INTRODUCTION

1.1 SCOPE OF THE DOCUMENT
The PUM document provides to user the usefulness information to take unfair advantage of RDT
product. It depicts the goal of the product and points out the necessary information of the algorithm
to understand meaning of RDT object. Lastly, this document describes the list of configurable
parameters useful for users and provides some examples of product visualisation.



1.2 SCOPE OF OTHER DOCUMENTS
The ATBD (Algorithm Theorical Basis Document) outlines the full algorithm of RDT: Cell
definition, Tracking and discrimination algorithms.
The VR (Validation report) depicts the accuracy of RDT to classify the convective cloud object.
The discrimination skill is assessed on lightning occurrences.
The Interface Control Documents ICD/1 (Interface Control Document n°1) describes the External
and Internal Interfaces of the SAFNWC/MSG software.
The Interface Control Documents ICD/3 (Interface Control Document n°3) describes the input and
output data formats of the SAFNWC/MSG software.



1.3 SOFTWARE VERSION IDENTIFICATION
This document is compliant with versionV2011.of the SAFNWC software package.



1.4 IMPROVEMENT FROM PREVIOUS VERSION
   •   PGE11 v2011 takes advantage of NWP data as input, for improving convective
       discrimination :
           o NWP data are used to compute convective indexes for synthesizing a “NWP
             convective mask”.
           o NWP data are used to compute (ECMWF NWP) or identify (Meteo-France
             ARPEGE NWP) Tropopause characteristics
           o Distance (°C) to Tropopause and value of convective index affected to each cell are
             used as additional predictors for statistic models issued from PGE11 tuning.
           o PGE11 Tuning has benefit from the convective mask, ignoring trajectories in stable
             areas thus reducing the unbalance between convective and non convective
             populations, and taking into account new parameters in the logistic regressions
                                                                 Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                 Issue:         2.2 Date:22    October
                                  Product User Manual for “Rapid
                                  Development    Thunderstorms” 2010
                                  (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                 11_v2.2
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            o Real time processing : Convective diagnostic of PGE11 is attempted except in
              stable areas of this convective mask, thus avoiding non relevant diagnostic. It also
              benefits from a better tuning, especially in warm categories.
       It is to note that PGE11 v2011 can be processed without NWP data. The result will in this
           case be comparable to V2010, but it must be kept in mind that v2011 has benefit from a
           better tuning (see ATBD), even if NWP data are not available in real time. In any case,
           NWP data are strongly recommended.
   •    Minor improvement concern displacement estimation :
            o validity tests have been introduced, to invalid erroneous values. In this case
              persistence will be applied
            o displacement is estimated from the move of gravity center of Cloud tops
   •    A production number can be encoded in BUFR file, to identify RDT productions over
        various areas and/or satellites
   •    It is to note that, since v2010, PGE11 is compliant with, and adapted to rapid scan mode.
        No specific configuration file (*.cfm) is needed by PGE11 when running on MSG01-
        rapidscan mode, but only adapted regression coefficients matrices for convective
        discrimination. Those matrices are prepared during the tuning phase of convective
        discrimination, in the same conditions from MSG02 (nominal mode) and MSG01 (rapid
        scan mode) data.
        Since frequency is read from satellite configuration file and checked from processed data,
        PGE11 automatically identifies the needed regression matrix, available in the
        $SAFNWC/import/Aux_data/PGE11/files_for_discri/ directory :
            ConvCoeffRegr (and ConvCoeffRegr_mask) for nominal mode (frequency 15 min)
            ConvCoeffRegr_5 (and ConvCoeffRegr_5_mask) for rapid scan mode (frequency 5
            min)

1.5 DEFINITIONS, ACRONYMS AND ABBREVIATIONS
BUFR           Binary Universal Form for the Representation for Meteorological data
CMa            Cloud Mask (also PGE01)
ECMWF          European Center for Meteorological Weather Forecasting
EUMETSAT European Meteorological Satellite Agency
GOES           Geostationary Operational Environmental Satellite
ICD            Interface Control Document
INM            Instituto Nacional de Meteorología
MSG            Meteosat Second Generation
MTR            Mid Term Review
NMS            National Meteorological Service
NWP            Numerical Weather Prediction
PGE            Product Generation Element
POD            PrObability of good Detection
                                                                         Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                         Issue:         2.2 Date:22    October
                                          Product User Manual for “Rapid
                                          Development    Thunderstorms” 2010
                                          (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                         11_v2.2
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POFD              PrObability of False Detection
RDT               Rapid Development Thunderstorms
SAF               Satellite Application Facility
SAF NWC           SAF to support NoWCasting and VSRF
SEVIRI            Spinning Enhanced Visible & Infrared Imager
SUM               Software User Manual
CDOP              Continuous Development and Operation Phase
IOP               Initial Operation Phase

1.6 REFERENCES

1.6.1 Applicable documents
 Reference                           Title                                   Code                       Vers
[AD.1.]       Algorithm Theorical Basis Document                SAF/NWC/CDOP/MFT/SCI/ATBD/11          2.2
[AD.2.]       Validation report                                 SAF/NWC/CDOP/MFT/SCI/VR/11            2.0
[AD.3.]       Interface Control document for the External and   SAF/NWC/CDOP/INM/SW/ICD/1             2011
              Internal Interfaces
[AD.4.]       Interface Control Document for the input and      SAF/NWC/CDOP/INM/SW/ICD/3             2011
              output data formats
[AD.5.]       Software User Manual for the SAFNWC/MSG           SAF/NWC/CDOP/INM/SW/SUM/2             2011
              Application, Software Part




1.6.2 Reference documents




2. DESCRIPTION OF THE PRODUCT

2.1 GOAL OF THE RDT PRODUCT
The RDT product has been developed by Meteo-France in the framework of the EUMETSAT SAF
in support to Nowcasting. Using mainly geostationnary satellite data, it provides information on
clouds related to significant convective systems, from meso scale (200 to 2000 km) down to smaller
scales (tenth of km). It is provided to users in the form of numerical data stored in a BUFR format
file. The objectives of RDT are twofold:

    •     The identification, monitoring and tracking of intense convective system clouds

    •     The detection of rapidly developing convective cells, where IR sensor allows for

The object-oriented approach underlying the RDT product allows to add value to the satellite image
by characterizing convective, spatially consistent, entities through various parameters of interest to
the forecaster : motion vector, cooling and expansion rate, cloud top height,…, and associated time
series of these parameters. It supports easyly and meaningfully downstream data fusion (surface
observations, NWP fields, radar data...).
                                                                  Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                  Issue:         2.2 Date:22    October
                                   Product User Manual for “Rapid
                                   Development    Thunderstorms” 2010
                                   (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                  11_v2.2
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Thereby, RDT is a tool for forecaster but can be used by research teams too, and end-users like
aeronautical users.

Finally, a Meteosat-based real-time demonstration is available for registered NMS on the Internet,
at this address: http://www.meteorologie.eu.org/RDT/index.html. A training material is available on
EUMETrain Website http://www.zamg.ac.at/eumetrain/.



2.2 OUTLINE OF THE ALGORITHM
The RDT algorithm could be divided into three parts:

   •   The detection of cloud systems

   •   The tracking of cloud systems

   •   The discrimination of convective cloud objects

2.2.1 The detection of cloud systems

The detection algorithm allows to define “cells” which represent the cloud systems. In the RDT
algorithm, “cells” are defined on infrared images (channel IR10.8) by applying a threshold which is
specific to each cloud system, and chosen considering local brightness temperature pattern. A good
understanding of this process is essential to make the best use of RDT.

The basic idea is to adapt the threshold use to the topography of the cloud tops:
                                                                     In the case of simple topography
                                                                     (like the simple, isolated, cloud
                                                                     associated to a single convective
                                                                     cell in clear air, at development
                                                                     stage), the threshold chosen
                                                                     corresponds to the outer limits
                                                                     of the cloudy zone

                                                                      In more complex cases, the
                                                                      principle is to use the warmest
                                                                      temperature threshold which
                                                                      allows to get one cell for each
                                                                      cloud "tower". A cloud tower is
                                                                      here formally defined as a local
                                                                      brightness temperature minima
                                                                      which is separated from the
                                                                      other, nearby, minimas by a
                                                                      sufficiently warmer zone (6°C
                                                                      warmer)

              Figure 1: RDT cell definition

Hence, the threshold use for a given cloud tower depends on the temperature pattern in the vicinity,
and may evolve just because nearby towers do evolve ( warmer zone or Deltat_tower=6°C for
defining significant cloud towers, which contour are drawn in red).
                                                                 Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                 Issue:         2.2 Date:22    October
                                  Product User Manual for “Rapid
                                  Development    Thunderstorms” 2010
                                  (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                 11_v2.2
                                                                 Page:                           10/22


Thus, the RDT cells linked in time to form a trajectory do not necessarily really depict the same
phenomena along time. But the advantage of the method used (adaptative threshold) is to focus on
convective parts of cloud systems, in order to perform the discrimination process.



2.2.2 The tracking of cloud systems

The adaptative threshold used makes complex the cell comparison due to various phenomena
depicted. This method induces numerous merges or splits.
The tracking algorithm is mainly built on the overlapping between cells in two successive images.
Before the cells overlap processing, the previous cells are moved according to their move and
speed (formerly analyzed). Nevertheless, correlation or neighborhood methods are applied when
overlapping method doesn't succeed. The temporal links are processed as follow:
       No match: the current cell is a new one and begins a new trajectory

       Merge: more than one former cell match with one current cell. The trajectory of the
       "largest" former cell is kept; the other ones are closed. Due to adaptative threshold
       temperature use, the largest former cell is not directly defined on its area attribute but on a
       area defined at a common threshold.

       Split: One former cell match with several current cells. The "largest" current cell carries out
       the time series. The other ones are processed like new cells.

       Merge and split: Several former cells match witch several current cells: In this case (less
       than 3% of trajectories), all trajectories are closed and the current cells are processed like
       new cells.

The temporal link allows to compute move, speed and trend of all cloud objects. The time series of
cloud's characteristics (peripheral gradient, volume, cooling rate...) are key input for the
discrimination algorithm.


2.2.3 The discrimination of convective objects
As it was mentioned previously, the RDT detection algorithm is able to detect cloud structure
from meso scale (200 to 2000 km) down smaller scale. The goal of the discrimination method
is to identify the convective RDT objects among all cloud cells, adding a strong constraint : the
discrimination should be effective as soon as possible after the first detection by RDT
software.
                                                                 Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                 Issue:         2.2 Date:22    October
                                  Product User Manual for “Rapid
                                  Development    Thunderstorms” 2010
                                  (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                 11_v2.2
                                                                 Page:                           11/22




                     Figure 2: RDT objects before convective discrimination

The previous figure displays all RDT detected cells. This picture points out the detection and
tracking efficiency of RDT. We can notice the phenomena and scale diversity of RDT objects.

The next figure displays convective objects only. The ratio between no convective and convective
objects is about 100.




                      Figure 3: RDT objects after convective discrimination

The discrimination method makes use of discrimination parameters calculated from infrared 10.8,
IR12.0, IR8.7 and two vapour channels (WV6.2 and WV7.3) characteristics. Two kinds of such
discrimination parameters are computed:
                                                                  Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                  Issue:         2.2 Date:22    October
                                   Product User Manual for “Rapid
                                   Development    Thunderstorms” 2010
                                   (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                  11_v2.2
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       spatial characteristics (extremes, peripheral gradient, surface)

       temporal characteristics (cooling rate, parameters trend)

The discrimination method is based on a statistical approach. It uses a learning data base to tune
statistical models of the discrimination scheme. The imbalance number between convective and
non-convective objects leads to strongly increase false detection for light improvement of detection
efficiency.
For that reason NWP data have been used to restrict the region of interest to “non–stable” areas.
Numbers of electric and non electric systems become closer even in low layer (warm categories),
which allows a more robust tuning of statistical models.
Moreover, some NWP attributes, when available as optional input, can be used as additional
predictor : distance (°C) to tropopause and maximum Lifted index in the nearest of cell.
The ground truth used for building the data base is cloud to ground lightning occurrence . For that
reason the current learning data base used to tune RDT discrimination algorithm is made over
widened France, where accuracy and efficiency of detection are reliable. The tuning domain of
V2011 is a little bit larger than for previous PGE11 releases, taking into account the former
improvments of detection efficiency and precision from Meteorage lightning network.
In order to process RDT on others satellites, the discrimination scheme has been tuned for two
others configurations than the “nominal” one :
   -   IR10.8and WV6.2 (defined for GOES data)
   -   IR10.8 (defined for METEOSAT 7)
Taking into account the possibility or not to use NWP data as optional input, six modes of
processing (configurations) are finally possible :
   -   IR10.8 , IR12.0, IR8.7, WV6.2, WV7.3 and NWP data (default configuration for MSG)
   -   IR10.8 , WV6.2 and NWP data
   -   IR10.8 and NWP data
   -   IR10.8 , IR12.0, IR8.7, WV6.2, WV7.3
   -   IR10.8 , WV6.2
   -   IR10.8
Even if the user’s configuration file does not correspond to the real time availability of data, PGE11
V2011 is able to adapt and detect automatically the best usable configuration among the ones listed
above. For that reason, each mode has benefit from a specific tuning.

2.3 DESCRIPTION OF THE OUTPUT
The final product is numerical data which depicts infrared characteristics (spatial and time) and
displacement information associated to RDT cells. Numerical data are provided in BUFR format.
Thus, operating the RDT needs a specific visualization tool.
RDT software is able to take in to account flashes location as optional input. These additional data
may allow to improve discrimination skill when they are used to force convective diagnosis for
missed convective cells (argument –lightning nb_of_flashes in configuration file). Moreover, the
object approach of RDT allows to summarize the lightning activity associated to a convective cloud
object and to build lightning time series.
                                                                  Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                  Issue:         2.2 Date:22    October
                                   Product User Manual for “Rapid
                                   Development    Thunderstorms” 2010
                                   (RDT-PGE11 v2.2)               File:          SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                  11_v2.2
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The BUFR format is described in the Interface Control Document n°3(# 1.6.1) of SAFNWC. The
RDT offers two BUFR versions (1 and 2 configurable with -bufr argument in configuration file).
The first version holds the full description of RDT cells without time series. The full RDT operating
needs to build time series from previous outputs. The second version provides three time series
(gravity center location, minimum temperature and lightning activity), allowing to make simpler the
visualization tool development. This version also may allow to limit the BUFR description to RDT
objects discriminated as convective (argument –bufr -2 in configuration file). This limitation leads
to strongly reduce BUFR size. .
The RDT V2011 processes a second output in ASCII format. This new file describes all cloud
trajectories ended during the time slot. This output is updated at each slot, in a dedicated, daily or
monthly file depending on argument “freq_traj” in configuration file (see below).


3. IMPLEMENTATION OF THE PRODUCT
The implementation of the PGE11 software follows the general implementation of components of
the SAFNWC/MSG software (see SUM of the SAF project #1.6.1).
Basically, the following steps are needed to proceed the PGE11 software:
   1. Create or update configuration files (system, region, and run configuration files) according
      to their format (see the Interface Control Document ICD/1 for the External and Internal
      Interfaces of the SAFNWC/MSG).
   2. Update, if necessary, the PGE11 configuration file
   3. Ensure that files for convective discrimination                      are     available   in   repository
      “$SAFNWC/import/Aux_data/PGE11/files_for_discri”:
           a. ConvCoeffRegr and ConvCoeffRegr_mask for MSG
           b. ConvCoeffRegr_5 and ConvCoeffRegr_5_mask for Rapid Scan
   4. Update the   files  “$SAFNWC/import/Aux_data/PGE11/PGE11_BUFR_table”    ,
      “$SAFNWC/import/Aux_data/PGE11/PGE11_BUFR_table_Nprod”,
      “$SAFNWC/import/Aux_data/PGE11/PGE11_BUFR_table2”                    and
      “$SAFNWC/import/Aux_data/PGE11/PGE11_BUFR_table2_Nprod” if needed.
   5. Ensure that the SEVIRI image file in HRIT format (mandatory input) is available in the
      directory $SAFNWC/import/SEVIRI_data/. To process PGE11 in real-time, the user has to
      refresh this file every 15 minutes with the most up-to-date data.
   6. Ensure that the directory $SAFNWC/import/NWP_data has been provided with latest NWP
      multigrib data, and that these data have been remapped by the TM on the specified region
      (remapped NWP data available in the $SAFNWC/tmp directory). PGE11 configuration file
      is used as guidance for the use and remapping of NWP data.
   7. Ensure that the lightning data file (optional input) is available in the directory
      $SAFNWC/import/Obs_data/. The name of this file must be “PGE11_lightning_data” and
      its content must be lightning data related to the processed SEVIRI image (see the Interface
      Control Document ICD/1 for the External and Internal Interfaces of the SAFNWC/MSG to
      have details on the format of this file). To process PGE11 in real-time, the user has to
      refresh this file every 15 minutes with the most up-to-date data. It is also recommended not
      to include unnecessary (old) lightning data in order to avoid useless processing.
Then, the processing of PGE11 is automatically monitored by the task manager (see the Software
Users Manual for the Task Manager of the SAFNWC/MSG software).
                                                                Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                Issue:         2.2 Date:22    October
                                 Product User Manual for “Rapid
                                 Development    Thunderstorms” 2010
                                 (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                11_v2.2
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4. INPUTS AND CONFIGURABLE PARAMETERS

4.1 LIST OF INPUTS

4.1.1 Mandatory inputs

Three different kinds of mandatory inputs are needed by the PGE11 software in order to proceed
correctly:


   1. Satellite images.
   These images are provided as input to the PGE11 software by the user. These images must be in
   HRIT      format    and    have      to    be   located    in    the     relevant   directory
   ${SAFNWC}/import/SEVIRI_data, (for more details please refer to the Software Users Manual
   for the SAFNWC/MSG software).


   2. Configuration files.
   Beside the SAFNWC general configuration files (system, run and region configuration files, see
   the Interface Control Document ICD/1 for the External and Internal Interfaces of the
   SAFNWC/MSG), the following configuration files must be created or updated in order to
   process PGE11 on a region:
       •   Files “PGE11_BUFR_table*”. They allow managing the initial version (default) or the
           version 2 of BUFR descriptors for the RDT product suitable for the user, with or
           without the extra option to encode a production number. These files are delivered with
           the SANWC/MSG and have to be updated by the user. They have to be located in the
           $SAFNWC/import/Aux_data/PGE11 directory. They allow the user to set the BUFR
           edition number, the version number of master tables used, the version number of local
           tables used, the code of the originating centre and the values of local descriptors
           defined in the RDT product (see the Interface Control Documents ICD/1 for the
           External and Internal Interfaces of the SAFNWC/MSG for more details on this file).
       •   PGE11 model configuration file. It is composed of keywords and values which will be
           used by the PGE11 software. It must be located in the $SAFNWC/config directory.
           The list of keywords and their significance is described into the next paragraph.


   3. Auxiliary files
   In order to perform a discrimination of convective systems, the PGE11 software makes use of
   discrimination             files         located          in          the            directory
   $SAFNWC/import/Aux_data/PGE11/files_for_discri. These files are delivered with the
   SAFNWC/MSG software and must not be modified by the user. For more details on these files,
   please refer to the Interface Control Documents ICD/1 for the External and Internal Interfaces
   of the SAFNWC/MSG.
                                                                 Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                 Issue:         2.2 Date:22    October
                                  Product User Manual for “Rapid
                                  Development    Thunderstorms” 2010
                                  (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                 11_v2.2
                                                                 Page:                           15/22


4.1.2 Optional inputs

Three optional inputs may be provided to PGE11 software:
   1. NWP data
   Even if optional from a technical and functional point of view, those data are strongly
   recommended for a more efficient product. Most recent NWP data have to be located in the
   directory $SAFNWC/import/NWP_data. When remapped in $SAFNWC/tmp directory, NWP
   data are used for two objectives:
       •   Reconstitute vertical profiles and compute instability indexes, to synthesize a “NWP
           convective mask” valid for the slot date. This mask allow to exclude stable areas from
           discrimination process, and thus to avoid eventual false alarms.
       •   Provide to discrimination scheme two extra parameters Lifted Index index and gap to
           tropopause (read or recomputed from NWP data)
     The PGE11 configuration file is used as guidance for the use and remapping of NWP data, by
       listing all desired parameters (see next section). The PGE11 default configuration file of
       SAFNWC package lists parameters compliant with either ARPEGE or ECMWF NWP
       data. Some parameters that are not available in one case may be estimated from others
       (relative humidity at 2m, ground height, tropopause characteristics).


   2. Lightning data file.
   In order to characterize electrical activity of convective systems (counting of lightning flashes
   detected below the cloud systems) and eventually to force the discrimination of convective
   systems using lightning data, the PGE11 software may use as input an ASCII file of lightning
   detection data. The name of this file must be “PGE11_lightning_data” and it has to be created
   and regularly updated in the directory $SAFNWC/import/Obs_data/.
   Its content must be lightning data (see the Interface Control Documents ICD/1 for the External
   and Internal Interfaces of the SAFNWC/MSG to have details on the format of this file) related
   to the processed SEVIRI image and in accordance with the chosen values of the parameters “-
   dt_light_before” and “-dt_light_after” of the model configuration file (see next section). More
   precisely, for a given SEVIRI slot:
           let Dfirst be the scanning time of the first pixel scanned by the SEVIRI radiometer in the
           processed region.
           let Dlast be the scanning time of the last pixel scanned by the SEVIRI radiometer in the
           processed region.
   Then, the lightning data file corresponding to this slot should include all the lightning data
   detected beetwen the times Dfirst – “-dt_light_before” and Dlast + “-dt_light_after”.
   To process PGE11 in real-time, the user has to refresh this file at the same frequency than
   PGE11 processing with the most up-to-date data. It is also recommended not to include
   unnecessary (old) lightning data in order to avoid useless processing.
   If such data are not provided as input, the only consequences are that the discrimination of
   convective systems is based only on satellite characteristics of the cloud systems and that the
   electrical characterization of convective systems is set to missing values.
   The choice to use or not lightning data as optional input to the PGE11 software is controlled by
   the parameter “-lightning” of the model configuration file (see next section).
                                                             Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                             Issue:         2.2 Date:22    October
                              Product User Manual for “Rapid
                              Development    Thunderstorms” 2010
                              (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                             11_v2.2
                                                             Page:                           16/22




3. CTTH product.
In the PGE11 software, it is possible to document the cloud top pressure of cloud systems
detected and tracked by the software. This is done through the integration of the CTTH product
of the SAFNWC/MSG into the RDT product.
This integration is optional. In order to use the CTTH product as input to the PGE11 software
the user has to ensure that i) the CTTH product is generated on the desired region and that ii)
the parameter “–ctth” of the model configuration file (see next section) is set to 1.
The integration of this CTTH into the RDT product is done as follows:
For a given detected cloud system, the corresponding cloud top pressure is defined as the 90%
percentile of the distribution of the CTTH product below the cloud system.
A quality of this estimated pressure is also estimated and is related to the pixels of the cloud
system which are considered to compute the 90% percentile of the CTTH_PRES parameter.
More precisely, the quality is defined as follows:
   •   If some pixels of the cloud system are “opaque” (i.e. the effective cloudiness, coming
       from the CTTH_EFFECTIVE parameter of the CTTH product, is equal to 100%), then
       the 90% percentile is evaluated only taking into account these pixels and the quality is
       set to “very good”.
   •   Else, if some pixels of the cloud system have an effective cloudiness greater or equal to
       90% and the quality of the processing of these pixels is “good” (see the
       CTTH_QUALITY parameter of the CTTH product), then the 90% percentile is
       evaluated only taking into account these pixels and the quality is set to “good”.
   •   Else, if some pixels of the cloud system have an effective cloudiness below 90%, then
       the 90% percentile is evaluated only taking into account these pixels and the quality is
       set to “medium”.
   •   Else, if the quality of the processing of some pixels is “good” (CTTH_QUALITY
       parameter of the CTTH product), then the 90% percentile is evaluated only taking into
       account these pixels and the quality is set to “low”.
   •   Else, the 90% percentile is evaluated only taking into account pixels for which the
       CTTH_PRES parameter was not “UNKNOWN” and the quality is set to “very low”.
                                                                       Code:      SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                       Issue:          2.2 Date:22    October
                                 Product User Manual for “Rapid
                                 Development    Thunderstorms” 2010
                                 (RDT-PGE11 v2.2)               File:              SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                11_v2.2
                                                                Page:                                         17/22


 4.2 CONFIGURABLE PARAMETERS
Keyword        Description                                Type           Possible Value(s)
PGE_ID         Identifier of the PGE11                    chain of       PGE11
                                                          characters
               SEVIRI bands to be used by the PGE         chain of       IR87,IR120, WV62,WV73,IR108
SEV_BANDS      algorithms                                 characters
NWP_PARAMxx    Surface Pressure                                          NWP_SP
                                                                         NWP_SP_TYPE
                                                                         NWP_SP_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Temperature at 2m                                         NWP_2T
                                                                         NWP_2T_TYPE
                                                                         NWP_2T_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Relative humidity at 2m                                   NWP_2RH
                                                                         NWP_2RH_TYPE
                                                                         NWP_2RH_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Dew point temp. at 2m                                     NWP_2D
                                                                         NWP_2D_TYPE
                                                                         NWP_2D_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Altitude                                                  NWP_ALTM
                                                                         NWP_ALTM_TYPE
                                                                         NWP_ALTM_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Geopotential at surface                                   NWP_SGEOP
                                                                         NWP_SGEOP_TYPE
                                                                         NWP_SGEOP_LEVEL
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Temperature at various pressure levels                    NWP_PT
(*)                                                                      NWP_PT_TYPE
                                                                         iii
                                                                         1
                                                                         BILIN
NWP_PARAMxx    Relative humidity at various pressure                     NWP_PR
(*)            levels                                                    NWP_PR_TYPE
                                                                         iii
                                                                         1
                                                                         BILIN
-Tcold         cold temperature threshold when            integer        Recommended value is –70
               multiple thresholding, deg Celsius,
               default –37
-Twarm         warm temperature threshold when            integer        Recommended value is 5
               multiple thresholding deg Celsius ,
               default -37
-delta_tempe   temperature step between Tcold and         integer        The CPU time needed by the PGE11
               Twarm, deg (default=2)                                    software is only slightly correlated with
                                                                         the chosen value, so we recommend to set
                                                                         the finest value 1.
-Amin          min detection area , km2, default 1\       float          Recommended value 60 (tuning value)
-Amax          Max detection area, km2, default           float          Recommended value 200000 (tuning
               400000                                                    value)
-cmask         0 (default) or 1 if using CT product       integer        0 or 1
               for masking non cloud pixels
-ctype         0 (default) or 1 if processing CT cell’s   integer        0 or 1
               attribute
-ctth          0 (default) or 1 if adding top cloud       integer        0 or 1
               attribute via CTTH product
-WV62          0 or 1 (default) if using WV6.2            integer        0 or 1
               channel into the discrimination scheme
-WV73          0 or 1 (default) if using WV7.3            integer        0 or 1
               channel into the discrimination scheme
                                                                                 Code:      SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                                 Issue:          2.2 Date:22    October
                                          Product User Manual for “Rapid
                                          Development    Thunderstorms” 2010
                                          (RDT-PGE11 v2.2)               File:               SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                         11_v2.2
                                                                         Page:                                              18/22


Keyword                 Description                                 Type           Possible Value(s)
-IR87                   0 or 1 (default) if using IR8.7 into the    integer        0 or 1
                        discrimination scheme
-IR120                  0 or 1 (default) if using IR12.0 into       integer        0 or 1
                        the discrimination scheme
-lightning              associating lightning flashes with cells:   integer        Default 0
                        0 (default) : no association
                        -1 : association without forcing
                        discrimination result
                        N : association with forcing
                        discrimination result from Nth impact
-dt_light_before        time step (sec) before image date for       integer        Recommended value 600 if lightning
                        associating lightning flashes, default                     managed
                        15*60
-dt_light_after         time step (sec) after image date for        integer        Recommended value 300 600 if lightning
                        associating lightning flashes, default                     managed
                        15*60
-fichier_foudre         absolute filename of lightning data         Chain of
                                                                    characters
-tolerance_foudre       maximum distance (nb. sat pixel)            integer        Default 0
                        between cell and flash to associate
                        both, default 0
-precocite              0 (default) or 1 if linear models of        integer        0 or 1
                        warmest categories shorter depth have
                        to be activated
-bufr                   production of BUFR file, version 1          integer        1 , 2 , -2
                        (default) or 2 (historical included).
                        <0 => only convective cells in BUFR
-bufr_histo             length in mn of historical content, bufr    integer        Recommended value 180 if version 2 of
                        version 2 only (default=180)                               BUFR

-info                   Informations on program running             integer        0 or 1
                        default 0 (no information)
-debug                  More precise Informations on program        inteer         0 or 1
                        running
                        default 0 (no information)\
-contours_region        To process full contour of the domain       integer        0 or 1
                        (1) or only 4 characteristic points                        Set the value at 0 to reduce cpu time of
                        (default 0)                                                RDT process and size of BUFR
- max_nbpile            Default =25000                              float          This value could be decreased depending
                        Technical parameter used to manage                         of local computer capacity.
                        the pile of local computer (equal to the
                        maximum size in pixel of a cell).
- num_prod              if necessary or requested, allows to        integer        User dependent
                        encode a production number in BUFR
- lignes_sortie         Activation of trajectory file production    character      Recommended TISLHX if trajectory file
                        by selecting the kind of information to                    requested
                        be included included
- freq_traj             Frequency of production of in               integer        0, 1 or 2 if trajectory file requested
                        trajectory file
                        0 = monthly
                        1 = daily (default)
                        2 = each slot
 (*) Temperature and relative humidity are requested to be remapped for each iiii pressure level of
 AV_PRESSURE_LEVELS covering ECMWF and ARPEGE levels.
 Default PGE11 model configuration file resulting of the PGE11 installation step, contains requests for remapping
 NWP parameters covering both ECMWF and ARPEGE specifications.
                                                        Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                        Issue:         2.2 Date:22    October
                         Product User Manual for “Rapid
                         Development    Thunderstorms” 2010
                         (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                        11_v2.2
                                                        Page:                           19/22


An example of such a PGE11 model configuration is given below:
       PGE_ID     PGE11
       SEV_BANDS IR87,IR120,WV62,WV73,IR108
       NWP_PARAM01 NWP_SP NWP_SP_TYPE NWP_SP_LEVEL 1 BILIN
       NWP_PARAM02 NWP_2T NWP_2T_TYPE NWP_2T_LEVEL 1 BILIN
       NWP_PARAM03 NWP_2D NWP_2D_TYPE NWP_2D_LEVEL 1 BILIN
       NWP_PARAM04 NWP_SGEOP NWP_SGEOP_TYPE NWP_SGEOP_LEVEL 1 BILIN
       NWP_PARAM05 NWP_PT NWP_PT_TYPE 1000 1 BILIN
       NWP_PARAM06 NWP_PR NWP_PR_TYPE 1000 1 BILIN
       NWP_PARAM07 NWP_PT NWP_PT_TYPE 950 1 BILIN
       NWP_PARAM08 NWP_PR NWP_PR_TYPE 950 1 BILIN
       NWP_PARAM09 NWP_PT NWP_PT_TYPE 925 1 BILIN
       NWP_PARAM10 NWP_PR NWP_PR_TYPE 925 1 BILIN
       NWP_PARAM11 NWP_PT NWP_PT_TYPE 900 1 BILIN
       NWP_PARAM12 NWP_PR NWP_PR_TYPE 900 1 BILIN
       NWP_PARAM13 NWP_PT NWP_PT_TYPE 850 1 BILIN
       NWP_PARAM14 NWP_PR NWP_PR_TYPE 850 1 BILIN
       NWP_PARAM15 NWP_PT NWP_PT_TYPE 800 1 BILIN
       NWP_PARAM16 NWP_PR NWP_PR_TYPE 800 1 BILIN
       NWP_PARAM17 NWP_PT NWP_PT_TYPE 700 1 BILIN
       NWP_PARAM18 NWP_PR NWP_PR_TYPE 700 1 BILIN
       NWP_PARAM19 NWP_PT NWP_PT_TYPE 600 1 BILIN
       NWP_PARAM20 NWP_PR NWP_PR_TYPE 600 1 BILIN
       NWP_PARAM21 NWP_PT NWP_PT_TYPE 500 1 BILIN
       NWP_PARAM22 NWP_PR NWP_PR_TYPE 500 1 BILIN
       NWP_PARAM23 NWP_PT NWP_PT_TYPE 400 1 BILIN
       NWP_PARAM24 NWP_PR NWP_PR_TYPE 400 1 BILIN
       NWP_PARAM25 NWP_PT NWP_PT_TYPE 300 1 BILIN
       NWP_PARAM26 NWP_PR NWP_PR_TYPE 300 1 BILIN
       NWP_PARAM27 NWP_PT NWP_PT_TYPE 250 1 BILIN
       NWP_PARAM28 NWP_PR NWP_PR_TYPE 250 1 BILIN
       NWP_PARAM29 NWP_PT NWP_PT_TYPE 200 1 BILIN
       NWP_PARAM30 NWP_PR NWP_PR_TYPE 200 1 BILIN
       NWP_PARAM31 NWP_PT NWP_PT_TYPE 150 1 BILIN
       NWP_PARAM32 NWP_PR NWP_PR_TYPE 150 1 BILIN
       NWP_PARAM33 NWP_PT NWP_PT_TYPE 100 1 BILIN
       NWP_PARAM34 NWP_PR NWP_PR_TYPE 100 1 BILIN
       NWP_PARAM35 NWP_PT NWP_PT_TYPE 70 1 BILIN
       NWP_PARAM36 NWP_PR NWP_PR_TYPE 70 1 BILIN
       NWP_PARAM37 NWP_2RH NWP_2RH_TYPE NWP_2RH_LEVEL 1 BILIN
       NWP_PARAM38 NWP_ALTM NWP_ALTM_TYPE NWP_ALTM_LEVEL 1 BILIN
       NWP_PARAM39 NWP_TT NWP_TT_TYPE NWP_TT_LEVEL 1 BILIN
       -Tcold -75
       -Twarm 5
       -delta_tempe 1
       -Amin 60
       -Amax 200000
       -cmask 1
       -ctype 1
       -ctth 1
       -lightning 1
       -dt_light_before 900
       -dt_light_after 300
       -tolerance_foudre 3
       -precocite 1
       -bufr 1
       -max_nbpile 25000
                                                                  Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                  Issue:         2.2 Date:22    October
                                   Product User Manual for “Rapid
                                   Development    Thunderstorms” 2010
                                   (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                  11_v2.2
                                                                  Page:                           20/22


5. VALIDATION

5.1 SUMMARY OF VALIDATION RESULTS
The validation of RDT V2011 has been limited on study cases. Thus, the discrimination skill
processes on the previous version remains valid. The subjective evaluation points out some
improvements of the early detection thanks to tuning with NWP data (better performances of
warmest categories), and the decrease of false alarms number thanks to processing a NWP
convective mask from real time NWP data.


Result of RDT V2009 validation (objective evaluation):
      Validation results are available for RDT discrimination skill between convective and no
      convective objects.
      The objective validation has been done on summer 2005 over France. The lightning activity
      is used as ground truth.
      RDT V2009 improves the convective discrimination skill on various points. In first, the
      probability of detection of convective period is equal to 71%. The start of a convective period
      is defined on the first lightning occurrence on the convective section. Due to some delays on
      this reference, the probability of detection on convective single moment is smaller (59%).
      Nevertheless, more than 80% of good detection are detected before 30 minutes after the first
      occurrence.
      More than objective score, RDT V2009 provides a convective classification stable in time.
      The discrimination algorithm is focused on convective period. The convective systems are
      de-classified in time during decaying phase, avoided the tracking of un-interest objects. The
      false alarms are well diagnosed after a small track (45 minutes). We can notice the board
      effect elimination too.
      Thus, RDT V2009 provides a right depicting of convective phenomena, from triggering
      phase to mature stage. The RDT object allows to point out the interest area of a satellite
      image. It provides interest information on triggering and development clouds and on mature
      systems. Even if the precocity on the first lightning occurrence remains weak, the subjective
      evaluation confirms the precocity usefulness on moderate lightning activity.




5.2 KNOWN PROBLEMS AND LIMITATIONS
The tuning have been carried out on summer period and focused on moderate electrical RDT objects.
The discrimination score during winter period could be weak, but will take full benefit from the use of
NWP data to avoid false alarms.
                                                                  Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                                  Issue:         2.2 Date:22    October
                                   Product User Manual for “Rapid
                                   Development    Thunderstorms” 2010
                                   (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                                  11_v2.2
                                                                  Page:                            21/22


6. EXAMPLE OF PRODUCT VISUALISATION
The final product is numerical data which depict infrared characteristics (spatial and time) and
move information associated to RDT cells. Numerical data are provided under BUFR format (see
ICD3 #1.6.1). Thus, operating the RDT needs a specific visualization tool.
The study case below gives an example of a simple RDT operating tool.More elaborate systems
with downstream data fusion could take advantage of object approach like these of RDT product.

6.1.1 Example of simple visualization tool

This visualization tool is a simple display of BUFR information on a web page. This example was
derived from BUFR version 1. The same result, without area time series, could be reached with a
simple reading of BUFR version 2.
The background image is Meteosat infrared data. The different characteristics of convective object
are displayed through three levels of visualization:
       The first level corresponds to the superposition of graphical attributes on the corresponding
       infrared image. These graphical attributes are:

               A colored contour which defines cloud system edges. The color of this contour is
               related to the category of the system (developing, transition, mature).

               The thickness of this contour is related to the temperature tendency of systems: the
               greater the cooling, the thicker the contour.

               The style of the contour (dashed/plain) indicates whether the system is electrically
               active or not : dashed when no lightning paired or available, plain for lightning
               occurrence. If –lightning argument of PGE11 configuration file is >0, the electrical
               information is used to force the convective diagnostic. When –lightning argument is
               <0, flashes are paired without impact on convective diagnostic of the cell
               (visualization tool has to take into account this possibility of “non-detection” of
               electric cells).

               A yellow line shows the trajectory of the system (all previous locations of the centre
               of gravity of the system in past images).

               A black arrow shows the expected move of the system for the next half hour.

       The second level allows to access numerical values of some characteristics of the RDT
       object. These values are displayed into an interactive popup window. Its visualization is
       activated by moving the mouse inside the contour of the corresponding cloud system.

       The third level allows visualizing historical time series of some characteristics. The
       visualization of these series, as it was mentioned previously, is interactive and is activated
       by simple-click inside the contour of the corresponding RDT object:

               Number of positive and negative lightning impacts registered below the convective
               system.

               Area of the system at various brightness temperature thresholds.

               Threshold temperature and minimum temperature of cell.
                                                               Code:     SAF/NWC/CDOP/MFT/SCI/PUM/11
                                                               Issue:         2.2 Date:22    October
                                Product User Manual for “Rapid
                                Development    Thunderstorms” 2010
                                (RDT-PGE11 v2.2)               File:      SAF-NWC-CDOP-MFT-SCI-PUM-
                                                               11_v2.2
                                                               Page:                           22/22




                          Figure 4: Example of product visualisation

The EUMETRAIN website provides studies cases on convective triggering over France and Africa
(http://www.zamg.ac.at/eumetrain/NWCSAF_WS_June2004/Update/main.htm).

				
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