Organization of MODIS Atmosphere Products

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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

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MODIS Product Hierarchy
Level 1 Products
Less Processing
Granules
Granule - A 5 minute piece of an orbit
Used to produce
Level 2 Products
MOD - Terra product
Granules
MYD - Aqua product
Used to produce
Level 3 Products
Global composites of level 2 granules
More Processing
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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
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Level 1 Products
http//www.mcst.ssai.biz/mcstweb/L1B/product.html
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MODIS Atmosphere Processing Flow Chart
Level 0
Instrument Packet Data
MOD 01 Level 1A
Level 1
MOD 02 Calibrated Radiances Level 1B
MOD 03 Geolocation Data Sets
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MOD - Terra productMYD - Aqua productGranule -
A 5 minute piece of a MODIS orbitLevel 1
Products (granule)
Organization of the MODIS DATA
MOD02 Level 1B Calibrated geo-located
radiancesMOD03 1Km Geolocation Fields
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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.

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MOD04 Aerosol MOD06 CloudMOD05 Water
VaporMOD07 Atmosphere ProfileMOD35 Cloud
MaskMODATML2 Joint Product
MODIS LEVEL II PRODUCTS
Geophysical parameters derived from MODIS
radiances
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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 MayTerra (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.
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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.
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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.
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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!
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Level 2 Aerosol Product (AOD)
Level 3 Aerosol Product (AOD)
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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.

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Daily Level 3 MOD08_D3
Cloud optical thickness
Gaps due to No clouds
Cloud top pressure
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Cloud optical Properties Come with an Estimate of
the Errors for each retrieval
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Daily
Daily MOD08_D3 8-day MOD08_E3 Monthly
MOD08_M3
Less missing data with increasing time interval!
8 day
Monthly
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• 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

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MOD - Terra productMYD - Aqua productGranule -
A 5 minute piece of a MODIS orbitLevel 1
Products (granule) Level II Products
(granule)Level III Products (global)
Organization of the MODIS DATA
MOD02 Level 1B Calibrated geo-located
radiancesMOD03 1Km Geolocation Fields
Geophysical parameter derived from MODIS radiances
Daily global gridded products derived from the
level II products
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All things MODIS atmosphere productshttp//modis
-atmos.gsfc.nasa.govMODIS Level 1 Products
Descriptionhttp//www.mcst.ssai.biz/mcstweb/L1B/p
roduct.htmlMODIS Level II Products
Descriptionhttp//modis-atmos.gsfc.nasa.gov/produ
cts.htmlDetailed description of the aerosol
product and a link to the ATDBwhich describes
the aerosol algorithms in detail.http//modis-atm
os.gsfc.nasa.gov/MOD04_L2/index.html
References
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Understanding a MODIS File Name
MOD04_L2.A2001079.0255.005.2006289012028.hdf