The level-4 MODIS global Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) product is composited every 8 days at 1-kilometer resolution on a Sinusoidal grid. The MCD15A2 product includes the following Science Data Sets: LAI, FPAR, and a set of quality rating, and standard deviation layers for each variable.
The LAI variable defines the number of equivalent layers of leaves relative to a unit of ground area, whereas FPAR measures the proportion of available radiation in the photosynthetically active wavelengths that are absorbed by green vegetation. Both variables are used as satellite-derived parameters to calculate surface photosynthesis, evapotranspiration, and net primary production, which inputs are used to calculate terrestrial energy, carbon, water cycle processes, and vegetation biogeochemistry.
Temporal Coverage | March 5, 2000 – |
Area | ~10° km x 10° Lat/Lon |
Image Dimensions | 1200 rows x 1200 columns |
Spatial Resolution | 1 km |
File Size | 2 MB |
Projection | Sinusoidal |
Data Format | HDF-EOS |
No. of Science Data Sets (SDS) | 6 |
Science Data Sets for MODIS/Terra+Aqua Leaf Area Index/FPAR 8-Day L3 Global 1km SIN Grid V005 (MCD15A2):
Science Data Sets (HDF Layers) (6) |
UNITS |
BIT TYPE |
FILL |
VALID RANGE |
SCALE FACTOR |
---|---|---|---|---|---|
Fpar_1km | Percent | 8-bit unsigned integer | 249–255 | 0–100 | 0.01 |
Lai_1km | m2plant/m2ground | 8-bit unsigned integer | 249–255 | 0–100 | 0.1 |
FparLai_QC | Class flag | 8-bit unsigned integer | 255 | 0–254 | na |
FparExtra_QC | Class flag | 8-bit unsigned integer | 255 | 0–254 | na |
FparStdDev_1km | Percent | 8-bit unsigned integer | 248–255 | 0–100 | 0.01 |
LaiStdDev_1km | m2plant/m2ground | 8-bit unsigned integer | 248–255 | 0–100 | 0.1 |
The QA information in the following tables below is derived from a MCD15A2 V005 LAI/FPAR product’s HDF-EOS file. This information is also available from MCD15A2 product’s file specifications: ftp://modular.nascom.nasa.gov/pub/LatestFilespecs/collection5/
Every MCD15A2 product contains two QC layers: Table: 1 describes the general QC information contained in the Fpar_QC SDS, and Table 2 provides detailed information included in the FparExtra_QC SDS.
Table 1: MCD15A2.005 LAI/FPAR General QA (8-bit)
Bit No. |
Parameter Name |
Bit Comb. |
FparLai_QC |
---|---|---|---|
0 | MODLAND_QC bits | 0 | Good quality (main algorithm with or without saturation) |
1 | Other Quality (back-up algorithm or fill values) | ||
1 | Sensor | 0 | Terra |
1 | Aqua | ||
2 | DeadDetector | 0 | Detectors apparently fine for up to 50% of channels 1,2 |
1 | Dead detectors caused >50% adjacent detector retrieval | ||
3–4 | CloudState (inherited from Aggregate_QC bits {0,1} cloud state) | 00 | 0 Significant clouds NOT present (clear) |
01 | 1 Significant clouds WERE present | ||
10 | 2 Mixed cloud present on pixel | ||
11 | 3 Cloud state not defined, assumed clear | ||
5–7 | SCF_QC (five level confidence score) | 000 | 0, Main (RT) method used, best result possible (no saturation) |
001 | 1, Main (RT) method used with saturation. Good,very usable | ||
010 | 2, Main (RT) method failed due to bad geometry, empirical algorithm used | ||
011 | 3, Main (RT) method failed due to problems other than geometry, empirical algorithm used | ||
100 | 4, Pixel not produced at all, value coudn't be retrieved (possible reasons: bad L1B data, unusable MODAGAGG data) |
Table 2: MCD15A2.005 LAI/FPAR Detailed QA (8-bit)
Bit No. |
Parameter Name |
Bit Comb. |
FparExtra_QC |
---|---|---|---|
0–1 | LandSea Pass-Thru | 00 | 0 LAND AggrQC(3,5)values{001} |
01 | 1 SHORE AggrQC(3,5)values{000,010,100} | ||
10 | 2 FRESHWATER AggrQC(3,5)values{011,101} | ||
11 | 3 OCEAN AggrQC(3,5)values{110,111} | ||
2 | Snow_Ice (from Aggregate_QC bits) | 0 | No snow/ice detected |
1 | Snow/ice detected | ||
3 | Aerosol | 0 | No or low atmospheric aerosol levels detected |
1 | Average or high aerosol levels detected | ||
4 | Cirrus | 0 | No cirrus detected |
1 | Cirrus was detected | ||
5 | MODAGAGG_Internal_CloudMask | 0 | No clouds |
1 | Clouds were detected | ||
6 | MODAGAGG_Cloud_Shadow | 0 | No cloud shadow detected |
1 | Cloud shadow detected | ||
7 | SCF_Biome_Mask | 0 | Biome outside interval <1,4> |
1 | Biome in interval <1,4> |
MCD15A2 Fill Values
Table 1: For Fpar_1km and Lai_1km
Value |
Description |
---|---|
255 |
Fillvalue, assigned when: * the MODAGAGG surface reflectance for channel VIS, NIR was assigned its _Fillvalue, or * land cover pixel itself was assigned _Fillvalue 255 or 254 |
254 | land cover assigned as perennial salt or inland fresh water |
253 | land cover assigned as barren, sparse vegetation (rock, tundra, desert.) |
252 | land cover assigned as perennial snow, ice |
251 | land cover assigned as "permanent" wetlands/inundated marshlands |
250 | land cover assigned as urban/built-up |
249 | land cover assigned as "unclassified" or not able to determine |
Table 2: For FparStdDev_1km and LaiStdDev_1km
Value |
Description |
---|---|
255 |
Fillvalue, assigned when: * the MODAGAGG surface reflectance for channel VIS, NIR was assigned its _Fillvalue, or * land cover pixel itself was assigned _Fillvalue 255 or 254 |
254 | land cover assigned as perennial salt or inland fresh water |
253 | land cover assigned as barren, sparse vegetation (rock, tundra, desert.) |
252 | land cover assigned as perennial snow, ice |
251 | land cover assigned as "permanent" wetlands/inundated marshlands |
250 | land cover assigned as urban/built-up |
249 | land cover assigned as "unclassified" or not able to determine |
248 | no standard deviation available, pixel produced using backup method. |
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Sioux Falls, SD 57198-0001
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U.S. Geological Survey (USGS)
Center for Earth Resources Observation and Science (EROS)
47914 252nd Street
Sioux Falls, SD 57198-0001
Phone Number: | 605-594-6116 |
Toll Free: | 866-573-3222 |
866-LPE-DAAC | |
Fax: | 605-594-6963 |
Email: | lpdaac@eos.nasa.gov |
Web: | http://lpdaac.usgs.gov |