MODIS Land Data Processing – Current Situation and Progress
MODIS Land Data Processing – Current Situation and Progress
APEIS Capacity Building Workshop on Integrated Environmental Monitoring of the
Asia-Pacific Region
Beijing, ChinaSeptember 20, 2002
Mr. Robert WolfeNASA GSFC Code 922, Raytheon ITSS
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 2
Moderate Resolution Imaging Spectroradiometer (MODIS)
Moderate Resolution Imaging Spectroradiometer (MODIS)
• Launched December 1999 on NASA EOS Terra Polar Orbiting Satellite
• Whisk-broom scanner, 100° Field of View
• Orbit: Attitude 705 km, Inclination 98.2°, mean-period 98.9 min., 16-day repeat cycle, 10:30 am equatorial crossing time
• Senses entire equator every two days, daily full coverage above 30° latitude
• 36 spectral bands: 29 - 1 km, 5 - 500 m and 2 - 250 m nadir spatial resolution
• Second MODIS on Aqua Satellite
– 1:30 PM equatorial crossing time
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 3
Terra Launch: Dec. 18, 1999First Image: Feb. 24, 2000
Aqua Launch: May 04, 2002First Image: June 26, 2002
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 4July 25, 2002 – Lower Baja Peninsula
MODIS Terra(1750)
MODIS Aqua(2100)
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 5
MODIS Land BandsMODIS Land Bands
Bandnumber
Spatialresolution
Wavelength,nm
Waveband region
1 250 m 620-670 Red
2 250 m 841-876 Near-infrared
3 500 m 459-479 Blue
4 500 m 545-565 Green
5 500 m 1230-1250Near-infrared
6 500 m 1628-1652Shortwave infrared
7 500 m 2105-2135Shortwave infrared
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 6
Science TeamScience Team
• Formed 11 years ago
• 3 Disciplines: Land, Oceans, Atmosphere
• Responsibilities:– Algorithm Theoretical Basis Document
– Algorithms in Software: PGEs (Product Generation Executables)
– QA and Validation
• Support Groups– Science Data Support Team (SDST)
• Includes: Discipline Support Groups (Coordination)
– MODIS Calibration Support Team (MCST)• Includes: MODIS Flight Operations
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 7
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 Science Team was completively selected to develop peer-reviewed product generation algorithms (24 Principal Investigators, lead: Vince Salomonson)
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 8
MODISTrue color
East Coast ZoomMarch 3 2000
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 9
MODIS Production and DistributionMODIS Production and Distribution
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
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 10
MODIS Land Products* / ESE Research Themes
• Energy Balance Product Suite– Surface Reflectance– Land Surface Temperature– BRDF/Albedo– Snow Cover
• Vegetation Parameters Suite– Vegetation Indices– LAI/FPAR– NPP/PSN
• Land Cover/Land Use Suite– Land Cover/Vegetation Dynamics– Vegetation Continuous Fields– Vegetation Cover Change– Fire and Burned Area
Global Water Cycle and Energy
Balance
*Dependencies between products
Biology and Biogeochemistry of Ecosystems and the Global Carbon Cycle
Land Cover and Land Use Change
Atmospheric Chemistry and Aerosols
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 11
Product CharacteristicsProduct Characteristics
• HDF-EOS Format
• Average file size is about 70 MB
Type Interim Archive Total L2 Swath 1 5 6 ISIN/SIN 8 30 38 LAEA (Polar) 3 2 5 CMG (Geog.) 0 19 19 Total 12 56 68
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 12
Level 1 Process FlowLevel 1 Process Flow
EDOS
Level 0 Science, Ancillary
C1 Level 1A,
Geolocation
C3 Level 2 Cloud
Mask, Atmospheric
Profiles
D0 Ancillary Data (DAO, NMC)
C2 Level 1B Calibrated Radiances
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 13
Calibration Summary Calibration Summary
Terra MODIS• Terra MODIS has been stable for over 22 months• The multiple OBCs have proven to be valuable for on-orbit
characterization• Changes in system level response are well understood and have been
incorporated into the L1B software• One subsystem (power supply) has failed and a second (formatter) is
marginal (was just replaced) • There are no indications of additional problems• Current Geolocation is very accurate (~50 m)
Aqua MODIS• Aqua MODIS’ ground tests indicate performance better than Terra
MODIS• Initial on-orbit data indicates only minor changes from the pre-launch
test resultsBarnes/MCST
MODIS identifies
cloudclasses
Hi cloud
Mid cloud
Low cloud
Snow
Clear
Menzel/MODIS
Atmosp.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 15
C1, C2, C3 Level 1 Geo.,
L1B, Cld. Mask, Atmos. Prof.
L1 Level 2 Snow, Sea Ice, Fire
L3 Level 2 Land
Surf. Refl.
L4/4d Level 2/3 Daily
Land Surf. Temp./Emiss.
D0 Ancillary Data (DAO, NMC)
L5P Level 2G/3 Daily
Snow, Sea Ice
L5 Level 2G/3 Daily Geoang, Pointers,
Agg./Text., Land Surf. Refl.,
Fire, Snow
L10 Level 3 8-day
Land Surf. Refl., Fire (+daily),
Land Surf. Temp./Emiss. Snow, Sea Ice,
LAI/FPAR
Future
L12 Level 3 16-day
VI, BRDF, Intermed. VCC
L16a/b Level 3 daily,
8-day PSN
L14 Level 3 32-day Land Cov. DB,
VCC, VCF
L18 Level 3 96-day
Land Cover/Change
L16c Level 3 yearly
NPP
MODIS Land Process Flow
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 16
Surface Reflectance/Atmospheric Correction Products
Surface Reflectance/Atmospheric Correction Products
• Reflectance corrected for gaseous and aerosol scattering and absorption, surface adjacency effects caused by variations in land cover and atmospheric/surface coupling effect
• Building block for generation of a number of land products: VI, BRDF/Albedo and LAI/FPAR
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 17
Southern Africasurface reflectance - not correctedfor aerosols
MODLAND/Vermote
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 18
Southern Africa correctedfor aerosol
MODLAND/Vermote
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 19
8-Day Surface Reflectance Composite (detail)8-Day Surface Reflectance Composite (detail)
At-launch algorithm(till Nov. 2000)
Revised algorithm (Min Blue & shadow filter & min view angle)
MODLAND/Vermote
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 20
MODIS BRDF/Albedo ProductMODIS BRDF/Albedo Product
• Provides global measures of albedo, BRDF adjusted surface reflectance and surface anisotropy
• Inputs – Gridded Surface Reflectance
• Outputs – 16 days at a 1km gridded spatial resolution. – Albedos
• Bihemispherical (white-sky) • Directional hemispherical (black-sky) albedos local solar noon• 7 Spectral and 3 Broadband Albedos
– Nadir BRDF-adjusted Reflectances (NBAR)• 7 Spectral bands at mean overpass solar zenith angle
– BRDF kernel weights in 7 spectral bands
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 21
0.0 0.1 0.2 0.3 0.4 0.5
Global Broadband White-Sky Albedo (0.3-5.0µm)April 7–22 2001
10 km resolution, Hammer-Aitoff projection,produced by MODIS BRDF/Albedo Team
no data
MODLAND/Strahler et al.
No data
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 22
Global Composite Map of Nadir BRDF-Adjusted Reflectance (NBAR)April 7–22 2001
10 km resolution, Hammer-Aitoff projection,produced by MODIS BRDF/Albedo Team
no data
MODLAND/Strahler et al.
True color, MODIS Bands 2, 4, 3 No data
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 23
Key parameter of the global energy balance, reflecting much of the incident solar radiation back to space
Snow and Ice CoverSnow and Ice Cover
Eight-Day Composite Global Climate Modeling Grid Snow Map (5.6-km resolution, 1/20°) December 18 - 25, 2000
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 24
Nov 1-7, 2000 Nov 8-15, 2000
Change in maximum snow extent between two Change in maximum snow extent between two composite periods seen above (1.8 million sq. km)composite periods seen above (1.8 million sq. km)
9.0 million sq. km of snow cover 10.8 million sq. km of snow cover
Snow on both
Snow on Nov 1-7 only
Snow on Nov 8-15 only
Clouds
MODLAND/Hall et al.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 25
Land Surface Temperature (LST) and Emissivity
Land Surface Temperature (LST) and Emissivity
• Split-window and statistical regression techniques are used
• Good indicator of both the energy balance at the Earth’s surface and the greenhouse effect
• Useful for a wide variety of climate, hydrological, ecological, and biogeochemical studies
Eight-Day Composite day-time 1km LST (k) Sept. 13 - 20, 2000
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 26
Daytime LST as the red component, and Nighttime LST as the green and blue components (after histogram-equalization enhancement). Pixels with daytime LST values but without nighttime LST values are in red..
8-day LST Day-Night Comparison
LST NightLST Day
Color Composite
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 27
Vegetation IndicesVegetation Indices
• Used for global monitoring of vegetation conditions– Normalized Difference
Vegetation Index (NDVI) and an improved Enhanced Vegetation Index (EVI)
– EVI uses self-correcting atmospheric and soil calibration factors
– Play an important role in the derivation of the land cover and land cover change, FPAR, LAI, and thermal products
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 28
NDVI vs. EVINDVI vs. EVI
NDVI EVI
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 29
LAI and FPARLAI and FPAR
• Leaf Area Index (LAI) and Fractional Photosynthetically Active Radiation (FPAR)– LAI defines an important
structural property of a plant canopy which is the one-sided leaf area per unit ground area
– FPAR measures the proportion of available radiation in the photosynthetically active wavelengths (400 to 700 nm) that a canopy absorbs
LAI March-25-2000
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 30
MODIS LAI
MODIS FPAR
MODLAND/Myneni et al.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 31
MODIS Global 1-km Land CoverMODIS Global 1-km Land Cover
Inputs Primary:
View-angle corrected (nadir) surfacereflectance (NBAR), 7 land bands
Ancillary:
Spatial Texture from 250-m; enhanced vegetation index; snowcover; land surface temperature; directional information
Outputs
IGBP 17 classes, UMd 14-classes; BGC 6 BiomesClassification Confidences
Approach Supervised approach, Artificial neural networks, Decision trees, GAM Statistical Boosting Global Test Sites for Training and Testing System for Terrestrial Ecosystem Parameterization ( 920 sites ) – site labeling
test sites for training
MODLAND/Strahler et al
Beta Product Release date – April 27, 2001; Provisional Product June 1, 2001
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 32
Vegetative Cover Conversion and Continuous Fields
Vegetative Cover Conversion and Continuous Fields
Vegetative Cover Conversion
• Detects and labels changes in land cover
• Uses the 250m Surface Reflectance products
Vegetation Continuous Fields
• Percent cover for basic land cover types
• Post-launch product
Vegetation Continuous Fields
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 33
IGBP Land Cover Units (17)IGBP Land Cover Units (17)
Based on Life-Form, Height, and Cover Fraction
Natural Vegetation (11)
Evergreen Needleleaf
Forests
Evergreen Broadleaf Forests
Deciduous Needleleaf Forests
Deciduous Broadleaf Forests
Mixed Forests
Closed Shrublands
Open Shrublands
Woody Savannas
Savannas
Grasslands
Permanent Wetlands
Developed and Mosaic Lands (3)
Urban and Built-Up Lands
Croplands
Cropland/Natural Vegetation
Mosaics
Nonvegetated Lands (3)
Snow and Ice
Barren
Water Bodies
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 34
Provisional Land Cover Product June 01
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 35
Fire and Thermal AnomaliesFire and Thermal Anomalies
• Fire is an important ecosystem process and source of trace gas emissions.
• Identifies the location, timing and energy of fires
• Near-real time alerts of volcano and fire activity (experimental product)
• Burned area estimation and for use with global models (post-launch product) MODIS Fires, NW Australia, Oct 2, 2000
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 36
MODIS burned area composite NFDR Fuel model EF and CF from Ward and Hardy (1991)x x
Idaho/Montana September 5, 2000
0
500000
1000000
15000002000000
2500000
30000003500000
4000000
45000005000000
CO2 Fireemissions fromthis scene (Gg)
1995 Fossil FuelCO2 (Gg)
% Area burned in this scene relative to the
total in the U.S. in 2000
14%
86%
MODIS Fire Emissions
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 37
Left burned area algorithm results -> burning over days 249-290 (500m)
Right temporal composite of MODIS day and night active fires detected over same period (1km)
Keypurple - beginning of the time series (day 249) red - end of time series (day 290)white - insufficient data in the time series to make a burning decision
MODIS Burned Area Product Evaluation
MODLAND/Roy
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 38
MODIS Production and DistributionMODIS Production and Distribution
• MODIS production commenced Feb. 2000• Collection 1: Beta
– L1: 2/00 to 5/01– L2+ 2/00 to 3/01
• Collection 3: “Provisional” – L1: 2/00 to 9/02 (from 11/00 onward validated)– L2+: 11/00 to 9/02
• Collection 4: “Validated”– Ocean from 6/02 to 10/02 at 6 to 8X– Starting 11/02 for L1 and L2+ Land and Atmosphere at 3 to 4X– Reprocessing – 2/00 to 10/02– Extend time series back in time (preliminary):
A) 11/01 to 10/02; B) 11/00 to 10/01; C) 2/00 to 10/00
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 39
Software Development ProcessSoftware Development Process
Insert Testing
Science Software Transfer
Science Team Member
Develops Code
DAAC
Operations
Integration and Test Science
Dependency Testing
Science Data
Support Team
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 40
Science Code DeliveryScience Code Delivery
• Alpha/Beta (2-3 years before launch)– simulated data (MAS data)– data system test, sizing– interface testing
• Version 1 (1 year before launch)• Version 2 (at launch)
– Beta product quality
• Version 3 (first reprocessing)– Provisional product quality
• etc. (validated)
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 41
Processing Driven by Production RulesProcessing Driven by Production Rules
• Required and optional inputs– Upstream products, ancillary data– How long to wait
• Processing Period– 5 min., 1, 8, 16, 32 or 96 days, calendar
months, calendar years)
• Start of period (reset at beginning of year, 2-3 day overlap at end of year)
• On-line and near-line retention time
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 42
MODAPS DesignMODAPS Design
• Loader– Determines when products can be generated (generates individual tasks)
• Scheduler– Schedules all tasks
– Allocates system resources, monitors task
– Stage inputs, output product disposition
• Archiver– Moves data from disk to tape and back
• Importer/Exporter– Ingests L1 and Ancillary Data from DAAC
– Distributes L2+ data to DAACs and users
• GUIs (Graphical User Interfaces)– X-windows (Operator) and Web based (Operators and other users)
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 43
MODAPS HardwareMODAPS Hardware
• 80 Processors – 10 ECS Gflops– 6.3 Gflops available in ops. (excluding overhead)
– Compare to 4.2 Gflops load in ‘96 baseline
– Most processes’ load lower than baseline
• 44 TB disk – 800 MB/s aggregate access• 100 TB tape – 60 MB/s aggregate access
– Theoretical rate: 5.1 TB/day
– Actual for 8/16-day retrieves: 0.5 to 0.75 TB/day
– Space for about 100 days of data
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 44
MODAPS HardwareMODAPS Hardware
2 Fi
bre
Cha
nnel
s10
0Mby
tes/
sec
14 F
ibre
Cha
nnel
s10
0Mby
tes/
sec
HiP
PI c
hann
el80
0MB
/sec
SGI Origin 200080 250Mhz R10K processors
40GB memory
DAACs
100TB ADICTape Library
12 drives44TB RAID in44 filesystems
8 Fi
bre
Cha
nnel
s10
0Mby
tes/
sec
HiP
PI c
hann
el80
0MB
/sec
SGI Origin 300064 400Mhz R12K processors
32GB memory
DAACs
100TB ADICTape Library
12 drives35TB RAID in35 filesystems
2 Fi
bre
Cha
nnel
s10
0Mby
tes/
sec
Gigabit Ethernet100MB/sec
Science Team,Development and
Test Systems
Gigabit Ethernet100MB/sec
Science Team,Development and
Test Systems
4 Pentium III cpu’sDatabase ServerRunning Linux
4 Pentium III cpu’sDatabase ServerRunning Linux
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 45
Design IssuesDesign Issues
• Number of files vs. product size
• Disk vs. Tape
• Production rule complexity
• System reliability
• Interfaces (leaky pipes)
• Product Format– Map projection, Tiling – for global products
– Usability – heritage vs. improvements
– HDF-EOS, Metadata
• Network
• Long term archive
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 46
MODLAND GridsMODLAND Grids
• Fine resolution grids for the L2G, 3 and 4 products are based on two map projections: – Integerized Sinusoidal (ISIN) => Sinusoidal (SIN) Grid– Lambert Azimuthal Equal-Area (LAEA) (polar grids) – Almost all of the fine resolution products will be made in the
ISIN/SIN• 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.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 47
ISIN/SIN GridISIN/SIN Grid
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 48
MODIS Land ValidationMODIS Land Validation
• Uses a hierarchical measurement concept – focused on EOS Land Validation Core Sites – combining satellite and airborne data with ground based in-situ
measurements– augmented by established field sites and measurement networks,
e.g., LTERS, FLUXNET, AERONET
• Interacting with other Terra, NASA Earth Science Enterprise, and international instrument teams (GLI, ATSR, MERIS)
• Participates in community intensive field campaigns (LBA – South America, SAFARI 2000 – southern Africa)
• Collaborating with the data providers to make validation data openly available
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 49
Multiple Observations – Simple Case
Multiple Observations – Simple Case
Obs 2Obs 1
Obs 3 Obs 4Obs 2
Obs 1
a. About 50 % Overlap b. 25 % Overlap
Cell Cell
Multiple observations covering a single grid cell:• about 50% of overlap distributed into two observations, and • 25% of overlap distributed over four observations.
Observation Coverage (%)
Percent of Observations
75 to 100 16
50 to 75 57
25 to 50 37
0 to 25 0
Distribution of coverage for each of the observation with the largest intersection with a cell. The observations and grid cell are the same size and have the same orientation.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 50
L2G StackL2G Stack
L2G product with samespatial dimensions ascorresponding L3 tile
obs 3
obs 1
obs 2
obs i
Stack ofobservations peroutput grid cell
Observation i
Pointer information:granule pointer,line, sample, etc.
Geophysical parameters:e.g., land surf. reflectance,thermal anomalies, etc.
Viewing geometry:view zenith,solar zenith, etc.
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 51
MODIS Land QAMODIS Land QA
• Objectives– identify suspect and poor quality products, including propagation
of errors originating from upstream products and ancillary data– provide feedback to appropriate entities so that problems can be
rectified– flag product quality (via metadata stored at the DAACs)
• QA approach– lead by the LDOPE (Land Data Operational Product Evaluation)
facility – activities:
• Product specific QA tools • LDOPE QA product metadata database• Global browse images
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 52
Global BrowseGlobal Browse
http://modland.nascom.nasa.gov/browse
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 53
MODLAND SubgroupMODLAND Subgroup
MODIS Science Team Meeting, Jan 26 2001
Sept. 20, 2002 – APEIS Workshop – R. Wolfe 54
MODIS Snow CoverMODIS Snow over AsiaMODIS Snow over Asia