of 250m and a temporal granularity of 16 days. In addition, FPAR data was downloaded from 2001 to 2010.
MODIS might be so far, the most complex instrument built and flown on a spacecraft for civilian research purposes. The MODIS sensor provides higher
quality data for monitoring terrestrial vegetation and other land processes than the previous AVHRR, not only because its narrower spectral bands that enhance the
information derived from vegetation, but also because leading scientists are working as a team to improve the accuracy of the data from low level reflectance
data, to high level data, such as land cover, fire, land surface temperature, vegetation indices NDVI and EVI; EVI is the enhanced vegetation index, FAPR
LAI and GPP NPP Justice et al. 2002
3.4 Method
3.4.1 Data collection
MODIS data was used for this study. We login the MODISTerra Multiple Data Ordering Page to download MODIS data for our study sites. Since
Kalimantan has a wide area, it could not be covered by one single image of MODIS data. In order to cover the whole area of Kalimantan, the MODIS data
could be downloaded in a tile fashion, from which each tile covers approximately 10 latitude by 10 longitude.
For Kalimantan area, four images MODIS data was needed for EVI. MODIS Tool and GRADS 2.0 were the software used to process MODIS data.
The Figure 2 shows the general methodology adopted for this research.
MODIS EVI
Data Processing
Estimation of EVI
Spatial Distribution of NPP
Validation
Recommendation Mosaicking
End Start
Ground check
Figure 2 General Method of the Research
3.4.2 Data Processing
There was several remote sensing techniques applied in this research. The first step of the work was mosaicking the images. This was done by using MODIS
Tool and GRADS. Those software provided interactive capabilities for placing
non geo referenced images within a mosaic, and automated placement of geo referenced images within a geo referenced output mosaic and conduct the other
data processing. The same process was done for MODIS EVI and other data.
3.4.3 Measuring vegetation: Enhanced Vegetation Index EVI
In December 1999, NASA launched the Terra spacecraft, the flagship in the agency’s Earth Observing System EOS program. Aboard Terra flies a sensor
called the Moderate-resolution Imaging Spectroradiometer, or MODIS, that greatly improves scientists’ ability to measure plant growth on a global scale.
MODIS provides much higher spatial resolution up to 250-meter resolution, while also matching Advanced Very High Resolution Radiometer AVHRR’s
almost-daily global cover and exceeding its spectral resolution. In other words, MODIS provided images over a given pixel of land just as often as AVHRR, but
in much finer detail and with measurements in a greater number of wavelengths using detectors that were specifically designed for measurements of land surface
dynamics. Consequently, the MODIS Science Team prepared a new data product–
called the Enhanced Vegetation Index EVI that improved upon the quality of the NDVI product. The EVI took full advantage of MODIS’ new, state-of-the-art
measurement capabilities. The EVI is calculated similar to NDVI, but with corrections for some distortions in the reflected light caused by the particles in the
air as well as the ground cover below the vegetation. The EVI data product also does not become saturated as easily as the NDVI when viewing rainforests and
other areas of the Earth with large amounts of chlorophyll. Vegetation indices derived from remote sensing data provide information
about consistent, spatial and temporal comparisons of global vegetation conditions which was used to monitor the Earths terrestrial photosynthetic vegetation
activity. For example, the enhanced vegetation index EVI provides a measure of greenness of the vegetation that can be used to predict net primary production.
The Enhanced Vegetation Index EVI improves on the venerable NDVI. Derived from state-of-the-art satellite data provided by the MODIS instrument,
EVI improves on NDVIs spatial resolution, is more sensitive to differences in
heavily vegetated areas. The EVI is related to the optical measures of vegetation, a direct measure of photosynthetic potential resulting from composite chlorophyll,
leaf area, canopy cover, and structure. It is developed to optimize the vegetation signal with improved sensitivity in high biomass regions and improved vegetation
monitoring through a de-coupling of the canopy background signal and a reduction in atmosphere influences. The equation takes the form,
EVI = G ρ
NIR
– ρ
Red
ρ
NIR
+ C
1
ρ
Red
– C
2
ρ
Blue
+ L
Where, EVI = Enhanced Vegetation Index
G = Gain factor =2.5
ρ
NIR
= Near Infrared Reflectance ρ
Red
= Red Reflectance ρ
Blue
= Blue Reflectance C
1
= Atmosphere Resistance Red Correction Coefficients =1 C
2
= Atmosphere Resistance Blue Correction Coefficients =6.0 L
= Canopy Background Brightness Correction Factor =1
The input reflectance to the EVI equation may be atmospherically- corrected or partially atmosphere corrected for Rayleigh scattering and ozone
absorption. C1 and C2 are the coefficients of the aerosol resistance term, which uses the blue band to correct for aerosol influences in the red band. The canopy
background adjustment factor, L, addresses non-linear, differential NIR and red radiant transfer through a canopy and renders the EVI insensitive to most canopy
backgrounds, with snow backgrounds as the exception.
3.4.4 Estimation of Net Primary Production NPP
