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North Alabama Lightning Mapping Array (LMA) Overview by kmm63581

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									                      North Alabama Lightning Mapping
                            Array (LMA) Overview

                                               presented at


                      Total Lightning Applications, Transition, Evaluation, Science
                         and Technology (LATEST) Demonstration Workshop

                                              April 1-2, 2004


                                    Richard Blakeslee, NASA/MSFC



LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                         North Alabama Observation Systems
• The LMA is a component of the Severe Thunderstorm Observation, Research,
          and Monitoring Network (STORMnet) providing total lightning mapping.
• STORMnet (as part of SPoRT) is a project to improve severe and hazardous
          weather forecasting and warning through collaboration among NASA and
          University scientists, NWS forecasters, and commercial partners.


      RADARS



                                                                                   MIPS
                                                                                 (Profilers)




            LMA
                                                                                  ASOS

LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                               North Alabama LMA Site Map


          • 10 sensor sites                                      28 km

                       – longest link 35 km (22 mi)
                       – mean link 20 km (w/ relays)   35 km             25 km



          •              4 relay sites
          •              NSSTC central facility
          •              plan to add 2 sites             34 km




LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003                                                     3
                                                  LMA Hardware

                New Mexico Tech System
                • LMA Sensor Sites
                               – VHF ground plane antenna
                               – Sensor electronics / site computer
                                 (famous “green” box)
                               – Communications (mostly 2.4 GHz
                                 wireless Ethernet network link)

                • Relay Sites and Central Station
                               – PC router (up to 4 network links)
                               – Communications (multiple antennas
                                 require great care in channel selection)


LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                       LMA Site Installations
     – Sites selected on basis of noise level, ability to
               establish wireless com link, and low / no cost access
     – Installations include: water towers, public/private
               radio towers, user supplied towers/masts, utility
               poles, even a firetower and a building


                                                                         Water tower
                                                                             (Keel)




                           User supplied tower   Utility pole
                                 (Owen)            (AAMU)
                                                                   Commercial radio tower
LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003                                               (Drake)
                                        Ardmore                                      250 GB IDE
                                                                                     (removable drive
                                                                                                          LMA Network
                                                                AAMU
       Firetower
                                                                                            Putman
                                                                                                           Topology
                                                  Drake                                                 • Com links used for real
                      Owen                        (router)
                                                                                                           time data transfer and
                                          LMA                                                              network control.
                                                         GHCC
                                          (R/T)
                                                         (router)                                            – 300 kB/s or better for
                                                                                                              links under ~25 km
                                                                          (router)                          – 25 kB/s or less for links
                                                                              Monte Sano                      over ~25 km from multi-
                                                       NSSTC
                                                                                                              path signal propagation.

                               Boeing
                                                        Weeden
                                                        (router)
                                                                                           Keel         • Full resolution raw data
                                                                                                           (80 s) stored locally with
                                                                                                           250 GB removable hard
                                                                                                           drive.
               Hospital                                            (router)
                                                                       Green
                                        802.11 LAN
LATEST Workshop, NSSTC
                                        H/W LAN
Huntsville, AL April 1, 2003
                                          Network Operations

                               • Highly automated process
                                 – Includes adjusting signal threshold and real time processing

                               • Automatic threshold adjustment
                                 – Fair weather data rate maintained at 10% max possible rate
                                   (keeps raw data volume low during non-storm periods)
                                 – Thunderstorm data rate maintained at 20-99% max possible
                                   rate – this rule initiates when real time solution obtain.
                                     (sometimes occurs briefly in fair wx, e.g., aircraft detection)

                               • Automatic real time data processing

LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                      Network Status Monitoring


                       • Web-based tables
                               and graphs provide
                               status at a glance.
                       • Detailed information
                               can be viewed for a
                               single site or all sites
                               for a single category.
                       • Majority of network
                               problems can be
                               quickly diagnosed.




LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                               Network Status Monitoring (cont.)

                                                        Example of peak power
                                                        graphs from the web




LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                    Data Flow Highlights
                                                             Removable
                                                              disc array                   Full Resolution
                               Building       lmadp4         (IDE, firewire)
                                LAN                                                        Raw Data Input
                                                                                           250 GB IDE
                                                                                           removable drive



                                   RAID                RAID                    LMA      GHCC                   Real Time Raw
                                    3.2 TB   Discharge 2.4 TB Branch           Base     (router)
                                                                                                               Data Input
                                                                                                      LMA
                                                                                                     Network
                                                                                                      802.1



                                                                                                       WAN
                                                                                                      (LISDAD,
                                                                                                        Web,
                                                         DVD                                           AWIPS)




                                             Post processors (5)                  250 GB
                                                                               firewire disc




LATEST Workshop, NSSTC
                                                250 GB
Huntsville, AL April 1, 2003                 firewire disc
                                          LMA Data Processing

                  Real Time Data
                  • Real time decimated (500 s) raw data received from sites
                               – (max 2000 points per second)
                  • Solutions calculated (NSSTC)
                  • Product generation and distribution
                               – Web-based products (solution maps and network statistics)
                               – LISDAD II LMA input
                               – AWIPS LMA product (460km x 460km x 17 level, 2km x 2km x 1km bins
                  • Solution and product archival


LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                     LMA Data Processing (cont.)

                  Post Processing LMA Full Data
                  • Data retrieved manually from sites ~ once per month
                               – Full raw data rate (80 µs sample size, max rate 12,500 points/s)
                  • Max raw lightning data production is 50-60 GB per day
                               – ( ~6.5 GB / site / day )
                  • Time to process increases exponentially with data volume
                               – Software decimation applied if needed to provide reasonable processing
                                 time (results in trade-off in density of solutions vs. processing time)
                               – Plan to intercompare software decimation approach to NMT’s new
                                 second-by-second software thresholding



LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                                                    LMA Post Processing
                                                                                         Processing Time

                                                                                Data Volume        Processing Time vs. Data Volume

                                                         40000000
                                                                                                                               5/2/2003
                                                                                                                               (125 s)
                                                                                                                 y = 4E+06Ln(x) + 2E+07
                                                         35000000
                                                                                                                       R2 = 0.9341
                               Raw data volume (bytes)


                                                                       Most days processed
                                                                                                           3/30/2002
                                                                       at 200 s or less
                                                                                                            (80 s)
                                                         30000000

                                                                                                                                     50 to 1
                                                         25000000
                                                                                           3/30/2002
                                                                                            (125s)
                                                         20000000

                                                                                                              5/2/2003
                                                         15000000                                             (250 s)



                                                         10000000

                                                                                              5/2/2003
                                                                                              (500 s)
                                                         5000000
                                                                                       3/30/2002
                                                                                        (500 s)             2-5 to 1
                                                               0
                                                                0.01             0.1                   1                  10                   100


LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                                              Processing ratio (CPU time to storm time)
                               Post Processing: Re-sampling Data




                                 80 s window        500 s window
                                                     125
                                                     250
LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                               Flash Comparison (using first event)
                                         Full (80 s) vs Re-sampled (500 s)




                                • Statistics
                                • Statistics
                                   – Bill McCaul’s flash algorithm employed
                                     –
                                     –   Flashes detection: 93 decimated vs. vs. full (93%)
                                         Flashes detection: 10585 decimated 10411330 full (93%)
                                     –
                                     –   For flashes uncorrelated flashes we found the mean
                                         Many of thecorrelated within 0.1 sclearly correspond to noise
                                     –   From a flash detection efficiency standpoint, the real time
                                         absolute difference to be: 1.5-2 km lat/lon, 1.2 km altitude
                                     –   (500 s) data does quite well biased toward lower altitude
                                         Decimated event systematically


LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                    Algorithm and Error Analysis

                          Paper discussing source retrievals and errors will be
                          published in April:

                               Koshak et al., “North Alabama Lightning Mapping Array (LMA): VHF
                                 Source Retrieval Algorithm and Error Analyses,” J. Atmos. and
                                 Ocean Tech., 21 (4), 627-643, 2004.




LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                                 Data Management and Archival

                               Raw Data
                               • Case study periods (NWS input desirable)
                                  – re-analysis of cases in different ways or with improved algorithms
                               • Randomized 5 minute samples (twice per day)
                                  – track and assess network performance over time
                               • TRMM overpass periods (+/- 30 seconds)
                               Solution Data
                               • All real time solutions and products
                               • All post processed solutions

LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                       Data Management and Archival (cont.)

                               Volume
                               • Maximum production 40-60 GB raw data per day
                                  – 60 GB raw       1 GB solution, gzip’ed ~200 MB
                               • Fair Wx production (noise) 14 GB raw data per day
                                  – 14 GB raw (noise)     near 0 (e.g.,15 KB)

                               Archival Methods
                               • Raid 1 disk system
                               • Firewire drives (2x)
                               • DVD disks (2x min, 1-3 months per DVD)

LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003
                               Example of LMA Flash




LATEST Workshop, NSSTC
Huntsville, AL April 1, 2003

								
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