Leaf Area Index (LAI)

Introduction

LAI Define The sum of the one sided green leaf area per unit ground area.
Unit none
ATBD Ver.1 (Nov. 2011)
Ver.2 (Jun. 2020)
FAPAR Define Fraction of photosynthetically active radiation absorbed by vegetation
Unit none
ATBD Ver.1 (Nov. 2011)
Ver.2 (Jun. 2020)

Update contents of Ver2

  • ・Improved the algorithm and LUT
  • ・Modified the SD array (Image_data/Understory_NDVI --->>> Image_data/Overstory_LAI)
  • ・Modified QA flag

Stored Physical quantity

Ver.1 Ver.2

Ver1 Description
FAPAR Fraction of Absorbed Photosynthetically Active Radiation
LAI Leaf Area Index
QA_flag
Understory_NDVI Normalized Difference Vegetation Index
Ver2 Description
FAPAR Fraction of Absorbed Photosynthetically Active Radiation
LAI Leaf Area Index
QA_flag
Overstory_LAI Leaf Area Index

QA_flag information

Ver.1 Ver.2 Ver.1(Sample Image) Ver.2(Sample Image)

Bit ver1 Description FAPAR_L3_mask* LAI_L3_mask* Understory_NDVI_L3_mask*
0 no data 1: any of used bands are error 1 1 1
1 land/water 0: water >50%, 1: land > 50% 0 0 0
2 mixed with land/water 1: land and water > 1% 0 0 0
3 cloud 1: cloud 1 1 1
4 probably cloud 1: probably cloud 0 0 0
5 snow or ice 1: snow or ice 0 0 0
6 cloud shadow 1: shadow 0 0 0
7 The condition of sensor zenith angle is not good 1: vzan>40 or vzas < 40 0 0 0
8 land cover type land cover type for used LUT 0 0 0
9 land cover type land cover type for used LUT 0 0 0
10 land cover type land cover type for used LUT 0 0 0
11 quality level quality 0 0 0
12 quality level quality 0 0 0
13 Value could not be retrieved 1: LAI/FAPAR could not be retrieved 0 0 0
14 unavailability of understory NDVI 1: fixed value was assigned for understory NDVI 0 0 0
15 backup algorithm 1: backup algorithm was applied 0 0 0

* Bits masked by statistical processing are indicated by 1.

Bit ver2 Description FAPAR_L3_mask* LAI_L3_mask* Overstory_LAI_L3_mask*
0 no data 1: any of used bands are error 1 1 1
1 land/water 0: water >50%, 1: land > 50% 0 0 0
2 mixed with land/water 1: land and water > 1% 0 0 0
3 cloud 1: cloud 1 1 1
4 probably cloud 1: probably cloud 0 0 0
5 snow or ice 1: snow or ice 0 0 0
6 cloud shadow 1: shadow 1 1 1
7 The condition of sensor zenith angle is not good 1: vzan>40 or vzas < 40 1 1 1
8 land cover type land cover type for used LUT 0 0 0
9 land cover type land cover type for used LUT 0 0 0
10 land cover type land cover type for used LUT 0 0 0
11 quality level quality 0 0 0
12 quality level quality 0 0 0
13 Value could not be retrieved 1: LAI/FAPAR could not be retrieved 0 0 0
14 pol cloud or high-tau 1: pol cloud/high-tau 1 1 1
15 backup algorithm 1: backup algorithm was applied 1 1 1

* Bits masked by statistical processing are indicated by 1.

*Download:QA_flag(Ver1) Sample Image
*Download:QA_flag(Ver2) Sample Image

Attribute information

Ver.1 Ver.2

Ver1 Attribute Remarks
Attribute of Image_data
Attribute of Image_data Grid_interval 0.00208333 250m: 0.00208333
Grid_interval_unit deg
Image_projection EQA (sinusoidal equal area) projection from 0-deg longitude
Number_of_pixels 4800 250m: 4800
Number_of_lines 4800
FAPAR
FAPAR
16-bit unsigned integer
Slope 0.001
Offset 0
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 1000
Mask_for_statistics 9 Detail: QA_flag_information(~L3_mask)
Data_description Fraction of Absorbed Photosynthetically Active Radiation (FAPAR)
Unit NA
Spatial_resolution_unit degree
LAI
LAI
16-bit unsigned integer
Slope 0.001
Offset 0
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 8000
Mask_for_statistics 9 Detail: QA_flag_information(~L3_mask)
Data_description Leaf Area Index (LAI)
Unit m^2/m^2
Spatial_resolution_unit degree
Understory_NDVI
Understory_NDVI
16-bit unsigned integer
Slope 0.001
Offset -1
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 2000
Mask_for_statistics 9 Detail: QA_flag_information(~L3_mask)
Data_description Normalized Difference Vegetation Index
Unit NA
Spatial_resolution_unit degree
Ver2 Attribute Remarks
Attribute of Image_data
Attribute of Image_data Grid_interval 0.00208333 250m: 0.00208333
Grid_interval_unit deg
Image_projection EQA (sinusoidal equal area) projection from 0-deg longitude
Number_of_pixels 4800 250m: 4800
Number_of_lines 4800
FAPAR
FAPAR
16-bit unsigned integer
Slope 0.001
Offset 0
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 1000
Mask_for_statistics 49353 Detail: QA_flag_information(~L3_mask)
Data_description Fraction of Absorbed Photosynthetically Active Radiation (FAPAR)
Unit NA
Spatial_resolution_unit degree
LAI
LAI
16-bit unsigned integer
Slope 0.001
Offset 0
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 8000
Mask_for_statistics 49353 Detail: QA_flag_information(~L3_mask)
Data_description Leaf Area Index (LAI)
Unit m^2/m^2
Spatial_resolution_unit degree
Overstory_LAI
Overstory_LAI
16-bit unsigned integer
Slope 0.001
Offset 0
Spatial_resolution 0.00208333 250m: 0.00208333
Error_DN 65535
Minimum_valid_DN 0
Maximum_valid_DN 8000
Mask_for_statistics 49353 Detail: QA_flag_information(~L3_mask)
Data_description Leaf Area Index
Unit m^2/m^2
Spatial_resolution_unit degree

How to use

  • ・Physical quantity=DN*slope + offset
  • ・Valid values are during Minimum_valid_DN~Maximum_valid_DN