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MODIS Land and HDF-EOS HDF-EOS Workshop Presentation September 20, 2000 Robert Wolfe NASA GSFC Code...
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Transcript of MODIS Land and HDF-EOS HDF-EOS Workshop Presentation September 20, 2000 Robert Wolfe NASA GSFC Code...
MODIS Land and HDF-EOSMODIS Land and HDF-EOS
HDF-EOS Workshop PresentationSeptember 20, 2000
Robert WolfeNASA GSFC Code 922, Raytheon ITSS
MODIS Land Science Team Support
HDF-EOS Pres., Sept. 20, 2000 2
MODIS Land Science Team ProductsMODIS Land Science Team Products
• Goals :– operationally produce terrestrial remotely sensed products that may be
used by expert and non-expert community– establish a 10 year record that has continuity with precursor systems, e.g.,
AVHRR, and the future NPP and NPOESS VIIRS missions
• The MODIS products were developed primarily to serve the global change research community (MODIS has global, near daily coverage) and have many other potential applications
• The MODIS Land Science team was completively selected to developpeer-reviewed product generation algorithms (10 Principal Investigators, lead: Chris Justice, UVA)
HDF-EOS Pres., Sept. 20, 2000 3
MODIS Land Product Overview (1/3)MODIS Land Product Overview (1/3)
• Radiation Budget Variables– Surface
Reflectance– Surface
Temperature and Emissivity
– Snow and Ice Cover
– BRDF and Albedo
HDF-EOS Pres., Sept. 20, 2000 4
MODIS Land Product Overview (2/3)MODIS Land Product Overview (2/3)
• Ecosystem Variables– Vegetation Indices– Leaf Area Index
(LAI) and Fractional Photosynthetically Active Radiation (FPAR)
– Vegetation Production
– Net Primary Productivity (NPP)
HDF-EOS Pres., Sept. 20, 2000 5
MODIS Land Product Overview (3/3)MODIS Land Product Overview (3/3)
• Land Cover Characteristics• Fire and Thermal
Anomalies
• Land Cover
• Vegetation Cover Conversion
HDF-EOS Pres., Sept. 20, 2000 6
MODIS Production and DistributionMODIS Production and Distribution
• MODIS Land production commenced 02/26/2000
• Product checkout is underway, driven by instrument calibration, geolocation, algorithm code stability and data dependencies
• Land products Beta release from the DAACs began 08/04/2000
• Current products are for evaluation purposes
GSFC DAAC
Level 0 Instrument Data
NSIDC DAAC EDC DAAC
MODAPS
Level 1 Products
Ocean and Atmosphere
Products
Land Snow and Ice Cover Products
Land Non-cryospheric
Products
User Community
Level 1, Ocean and Atmos.
Products
User Community
HDF-EOS Pres., Sept. 20, 2000 7
MODLAND GridsMODLAND Grids
• Fine resolution grids for the L2G, 3 and 4 products are based on two map projections: – Integerized Sinusoidal Grid (ISIN)– Lambert Azimuthal Equal-Area (LAEA) (polar grids) – Almost all of the fine resolution products will be made in the ISIN
• Exception: Sea-ice products are made in the in the LAEA projection with the grid centered at the north and south poles (EASI Grid implementation)
– Grid cell size varies by product and is either (approx.) 0.25 km, 0.5 km or 1 km – actual size depends on the projection
– Each grid is broken into non-overlapping tiles which cover approx. 10 x 10 deg. area
• Coarse resolution global Climate Modeling Grid (CMG) products are made in a geographic projection with grid cell sizes of 0.25 or 0.5 deg.
HDF-EOS Pres., Sept. 20, 2000 8
ISIN GridISIN Grid
HDF-EOS Pres., Sept. 20, 2000 9
HDF-EOS Usage (1/2)HDF-EOS Usage (1/2)
• Both swath and grid format
• 2d, 3d and some 4d SDS arrays• Global and SDS attributes
Type Interim Archive Total L2 Swath 1 5 6 ISIN 8 30 38 LAEA (Polar) 3 2 5 CMG (Geog.) 0 19 19 Total 12 56 68
HDF-EOS Pres., Sept. 20, 2000 10
HDF-EOS Usage (2/2)HDF-EOS Usage (2/2)
• Subsetting/mosaicing– Collaborated with UAH in HEW development
– Used operationally for 24 Core Validation Sites and planned for Fluxnet sites
• Resampler– Collaborating with EDC/SDSM&T to develop resampler
– Could be used for DAAC services and end user
– L2 and L3 regridding support
• MODLAND developed QA Tools for Team– Extensions to IDL/ENVI and Unix command line
– Bit field handling, etc.
HDF-EOS Pres., Sept. 20, 2000 11
Good things about HDF/HDF-EOSGood things about HDF/HDF-EOS
• Made collaboration easier between geographically distant scientists/developers– Self documenting file format allows easy exchange of
information between processes
• Standard method of representing geolocation
HDF-EOS Pres., Sept. 20, 2000 12
HDF-EOS Gripes (1/2)HDF-EOS Gripes (1/2)
• Toolkit doesn't support all HDF objects and access types– Hybrid HDF and HDF-EOS approach used to create/read files– Also need to use SDP toolkit to manipulate metadata
• Subsettting on 3/4 dimensional arrays is difficult– ex. take bands 3 & 5 from 7 bands array (3d) and store
in 2 band array (3d)– downstream users need to which 2 bands were selected
• HDF Specific– No convention for support of bit fields– Performance depends on layout in 3 or 4 dimensional arrays
HDF-EOS Pres., Sept. 20, 2000 13
HDF-EOS Gripes (2/2)HDF-EOS Gripes (2/2)
• Swath format does not support external geolocation files– workaround -- two geolocation arrays: one accurate 1
km external file and one 5 km internal array
– 5 km array takes up more space and not as accurate• Vendor support growing but still lacking
HDF-EOS Pres., Sept. 20, 2000 14
For More InformationFor More Information
URL: http://modis.gsfc.nasa.gov/