The Boston University team collected several data sets along the Kalahari Transect during the SAFARI 2000 wet season field campaign from March 3 to March 18, 2000, to support the validation of the MODIS LAI/FPAR algorithm. Ground measurements of LAI, FPAR, leaf hemispherical reflectance, leaf hemispherical transmittance, and canopy transmittance were made using a LAI-2000 plant canopy analyzer, an AccuPAR ceptometer, a LiCor 1800-12S External Integrating Sphere (LI-1800) portable spectroradiometer, and an ASD handheld spectroradiometer. LAI data are provided in this data set.
LAI was intensively measured at four different sites in Botswana -- Pandamatenga, Maun, Okwa River, and Tshane (from north to south) -- where vegetation types range from moist, closed woodlands to arid, sparsely-shrub-covered grasslands. LAI measurements were mostly made during dusk, shortly before and after sunset at ground level in Maun, Okwa, and Tshane, and at two horizontal levels in Pandamatenga -- one 2.0 m above the ground to measure the LAI of trees and the other was at ground level for total LAI.
This data set contains reduced LAI measurements made at two scales: a 1 km x 1 km transect scale and a 250 m x 300 m pixel scale. The transect LAI data are stored in one ASCII file containing all measurements along the three transects at each site. The pixel or subgrid LAI are stored in separate ASCII files for each site.
Cite this data set as follows:
Myneni, R. B., Y. Tian, and Y. Wang. 2005. SAFARI 2000 LAI Measurements at Kalahari Transect Sites, Wet Season 2000. Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/770.
Tian, Y., C. E. Woodcock, Y. Wang, J. L. Privette, N. V. Shabanov, L. Zhou, Y. Zhang, W. Buermann, J. Dong, B. Veikkanen, T. Hame, K. Andersson, M. Ozdogan, Y. Knyazikhin, and R. B. Myneni. 2002. Multiscale analysis and validation of MODIS LAI product. I. Uncertainty assessment. Remote Sens. Environ. 83: 414-430.
Tian, Y., C. E. Woodcock, Y. Wang, J. L. Privette, N. V. Shabanov, L. Zhou, Y. Zhang, W. Buermann, J. Dong, B. Veikkanen, T. Hame, K. Andersson, M. Ozdogan, Y. Knyazikhin, and R. B. Myneni. 2002. Multiscale analysis and validation of the MODIS LAI product over Maun, Botswana. II. Sampling Strategy. Remote Sens. Environ, 83: 431-441.
The transect LAI data are stored in one ASCII file containing all measurements along the three transects at each site. The pixel or subgrid LAI data are stored in separate ASCII files for each site. Summary information regarding the data files and format is provided below.
Transect Scale LAI Data:
|Location||Transect grid location||ASCII|
|Maun LAI||Maun Leaf Area Index||unitless|
|Okwa LAI||Okwa Leaf Area Index||unitless|
|Tshane LAI||Tshane Leaf Area Index||unitless|
|Panda (tree) LAI||Pandamatenga tree Leaf Area Index (measured at 1.5 m)||unitless|
|Panda (total) LAI||Pandamatenga total vegetation Leaf Area Index (measured at ground level)||unitless|
Pixel Scale LAI Data:
|GRID||Sampling grid location||ASCII|
|DATE||Date of data acquisition||DD-MM-YY|
|TIME||Time of data acquisition (local time)||hh:mm:ss|
|LAI||Leaf Area Index from the LAI-2000 algorithm |
(one-sided green leaf area per unit ground area)
|SEL||Standard Error of the LAI determination||unitless|
|DIFN||Diffuse transmittance, the probability of diffuse radiation from above penetrating the canopy to a particular location.||fraction (0-1)|
|MTA||Mean tilt angle, the mean leaf inclination angle||degrees|
|SEM||Standard error of MTA||degrees|
Additional information about the study sites, data acquisition methods and instrumentation, and data format is found in the companion file: http://daac.ornl.gov/daacdata/safari2k/field_campaign/kt_lai/comp/kt_lai_readme.pdf.