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Everything You Need To Know About MODIS Data In Three Short Hours

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Everything You Need To Know About MODIS Data In Three Short Hours Powered By Docstoc
					Organization of MODIS
Atmosphere Products


Rich Kleidman
Science Systems and Applications

Rob Levy
Science Systems and Applications

Lorraine Remer
NASA Goddard Space Flight Center

Shana Mattoo, Alan Chu, Vanderlei
  Martins, Rong-Rong Li, and Yoram
  Kaufman
            MODIS Product Hierarchy
Level 1 Products       Less Processing
   Granules
                      Granule - A 5 minute
Used to produce         piece of an orbit


Level 2 Products
                                         MOD - Terra product
   Granules
 Used to produce                         MYD - Aqua product



Level 3 Products
Global composites
of level 2 granules    More Processing
           Level 1 Products
MOD021KM - 1KM calibrated geo-located radiances

 MOD02HKM - .5 KM calibrated geo-located radiances
      Bands        Nm          Name
       3         459-479       .47
        4        545-565        .55
       5         1230-1250      1.2
        6        1628-1652      1.6
       7         2105-2155      2.1
 MOD02QKM - .25 KM calibrated geo-located radiances
     Bands        Nm         Name
        1       620-660       .66
        2       841-876       .87

  http://www.mcst.ssai.biz/mcstweb/L1B/product.html
                      Level 1 Products

     ECS Short Name
                                                Product Contents
MODIS/Terra   MODIS/Aqua
MOD02QKM      MYD02QKM     Calibrated Earth View data at 250m resolution
                           Calibrated Earth View data at 500m resolution, including the
MOD02HKM      MYD02HKM     250m resolution bands aggregated to appear at 500m
                           resolution.
                           Calibrated Earth View data at 1km resolution, including the
MOD021KM      MYD021KM     250m and 500m resolution bands aggregated to appear at
                           1km resolution.
MOD02OBC      MYD02OBC     On Board Calibrator (OBC) and Engineering Data


     http://www.mcst.ssai.biz/mcstweb/L1B/product.html
MODIS Atmosphere Processing Flow Chart


      Level 0


                          Instrument Packet Data



                                 MOD 01
                                  Level 1A
      Level 1




                     MOD 02                  MOD 03
                Calibrated Radiances         Geolocation Data Sets
                       Level 1B
    Organization of the MODIS DATA
MOD - Terra product
MYD - Aqua product
Granule - A 5 minute piece of a MODIS orbit

Level 1 Products (granule)


MOD02 Level 1B Calibrated geo-located radiances
MOD03 1Km Geolocation Fields
 Formatting of MODIS products

All MODIS products come in HDF format.
In HDF format each file contains both data and
metadata

SDS - Each parameter within a MODIS HDF file is
referred to as an SDS
(Scientific Data Set)

An SDS must be referenced precisely according to
name when analyzing the data
with your own computer code.
       MODIS LEVEL II PRODUCTS
Geophysical parameters derived from MODIS radiances


           MOD04 Aerosol

           MOD06 Cloud

           MOD05 Water Vapor

           MOD07 Atmosphere Profile

           MOD35 Cloud Mask

           MODATML2 Joint Product
A few important terms for level 2
     and 3 derived products
 Collection refers to a coherent grouping of the data.
 A collection is usually processed by the same set of
 algorithms
 Aqua (MYD) products are currently collection 5.
 They will be reprocessed to collection 5.1 beginning in
 May
 Terra (MOD) products are collection 5. Reprocessing
 to collection 5.1 will begin after Aqua is completed.
 Changes in the calibration of the instrument may
 coincide with collection updates but are not
 integrated into algorithm changes.
 Reprocessing: Applying the same set of algorithms to
 the whole data set.
 Forward Processing: Applying the current algorithm to
 newly acquired data.
         MODIS Level II Products
             http://modis-atmos.gsfc.nasa.gov/products

MOD04 Aerosol
The Aerosol Product monitors aerosol type, aerosol optical thickness, particle size
distribution, aerosol mass concentration, optical properties, and radiative forcing.
MOD06 Cloud
The Cloud Product monitors the physical and radiative properties of clouds
including cloud particle phase (ice vs. water, clouds vs. snow), effective cloud
particle radius, cloud optical thickness, cloud shadow effects, cloud top temperature,
cloud top height, effective emissivity, cloud phase (ice vs. water, opaque vs. non-
opaque), and cloud fraction under both daytime and nighttime conditions.
MOD05 Water Vapor
The Water Vapor Product monitors atmospheric water vapor and perceptible water.
MOD07 Atmosphere Profile
The Atmosphere Profile Product monitors profiles of atmospheric temperature and
moisture, atmospheric stability, and total ozone burden.
MOD35 Cloud Mask
The Cloud Mask Product indicates whether a given instrument field of view (FOV) of
the Earth's surface is unobstructed by clouds or affected by cloud shadows. The
cloud mask also provides additional information about the FOV including the
presence of: cirrus clouds, ice/snow, and sunglint contamination. Finally flags
denoting day/night and land/water are included.
MODIS Level II Products - continued

  MODATML2 Joint Product - contains a spectrum
  of key parameters gleaned from the complete set of
  standard at-launch Level 2 products: Aerosol,
  Water Vapor, Cloud, Profile, and Cloud Mask. The
  Joint Atmosphere product was designed to be
  small enough to minimize data transfer and
  storage requirements, yet robust enough to be
  useful to a significant number of MODIS data
  users. Data are stored at 5-km and 10-km (at
  nadir) spatial resolutions.
    Level 3 - Where all atmospheric
       products come together
http://modis.gsfc.nasa.gov/data/dataprod/pdf/MOD_08.pdf


     One degree resolution, so products are averaged from
     their native retrieval resolution.

     Averaging is either straightforward or weighted by
     QA flag.
              Daily, 8-Day, and monthly averages available.

     Note: One grid square can contain multiple orbits.
     Level 3 is not synchronous in time!
Level 2 Aerosol Product (AOD)




  Level 3 Aerosol Product (AOD)
Daily L3 aerosol optical thickness over land
                 and ocean




      The large gaps over ocean are due to Sunglint
      The gaps over land are due to bright surfaces and
      gaps due to cloud systems.
      Regularly spaced gaps near the equator are due
      to lack of coverage between orbits.
              Daily Level 3 MOD08_D3
Cloud optical thickness




                                  Gaps due to
Cloud top pressure                No clouds
Cloud optical
Properties
Come with an
Estimate of the
Errors for each
retrieval
Daily

             Daily = MOD08_D3
             8-day = MOD08_E3
             Monthly =MOD08_M3

               Less missing data
              with increasing time
                    interval!




8 day   Monthly
                     Level 3

Comes with an array of statistics:
Means, standard deviations, max and min retrieval
 in each grid box.
Histograms and joint histograms between products.
Number of pixels that went into the mean of
 each grid box
Organization of the MODIS DATA

MOD - Terra product
MYD - Aqua product
Granule - A 5 minute piece of a MODIS orbit

Level 1 Products (granule)
Level II Products (granule)
Level III Products (global)

MOD02 Level 1B Calibrated geo-located radiances
MOD03 1Km Geolocation Fields

Geophysical parameter derived from MODIS
radiances

Daily global gridded products derived from the level
II products
                 References
All things MODIS atmosphere products:
http://modis-atmos.gsfc.nasa.gov

MODIS Level 1 Products Description
http://www.mcst.ssai.biz/mcstweb/L1B/product.html


MODIS Level II Products Description
http://modis-atmos.gsfc.nasa.gov/products.html

Detailed description of the aerosol product and a link to
the ATDB
which describes the aerosol algorithms in detail.
http://modis-atmos.gsfc.nasa.gov/MOD04_L2/index.html
     Understanding a MODIS File Name


                           Time          Collection


MOD04_L2.A2001079.0255.005.2006289012028.hdf




Product Name   Date - year, Julian day       File processing information

				
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