User Manual - pancroma

46. Working with MODIS Surface Reflectance Data________________________________________________________________PANCROMA TM can import MODIS surface reflectance data designatedMOD09/MYD09 - Surface Reflectance; Atmospheric Correction AlgorithmProducts from both the Terra or Aqua satellites. The MODIS surface reflectanceproducts are generated from the first two, or seven, bands of the correspondingfull 36 band scenes. These provide estimated “at surface” spectral reflectancevalues. Algorithms are applied to the MODIS bands to remove the effects ofcirrus clouds, water vapor, aerosols and atmospheric gases. Global surfacereflectance products can be obtained at either 250 m or 500 m spatial resolution,and as daily or 8-day composite images. The seven multispectral bands arecentered at 648 nm, 858 nm, 470 nm, 555 nm, 1240 nm, 1640 nm, and 2130 nm,respectively, red, NIR, blue, green, NIR, NIR, NIR). Details of the surfacereflectance products are as follows:MOD09GQ/MYD09GQ - MODIS Surface Reflectance Daily L2G Global 250mThis product has a spatial resolution of 250 m and contains two bands of spectraldata centered at 645 nm and 858 nm.MOD09GA/MYD09GA - MODIS Surface Reflectance Daily L2G Global 500mThis product has a spatial resolution of 500 m and contains seven bands ofspectral dataMOD09Q1/MYD09Q1 - MODIS Surface Reflectance 8-Day L3 Global 250mThis product is a composite using eight consecutive daily 250m images. The bestobservation during each eight day period, for every cell in the image, is retained.This helps reduce or eliminate clouds from a scene. The file contains the samespectral information as the daily file listed above, centered at 645 nm and 858nm. There is one additional band of data for quality control.MOD09A1/MYD09A1 - MODIS Surface Reflectance 8-Day L3 Global 500mThis file is a composite using eight consecutive daily 500 m images. Again, thebest observation during each eight day period, for every cell in the image, isretained. This helps reduce or eliminate clouds from a scene. The file containsthe same seven spectral bands of data as the daily file listed above.To access the data, open your MODIS HDF data file. Do this by selecting‘ASTER L1B, SPOT VEG HDF, MODIS 250m, MODIS 500m’ from the File Typedrop down box and then clicking on your MODIS scene. Then select ‘DisplayFiles’ | ‘Display Single Grayscale Band Image’. When the MODIS BandSelection Form becomes visible, select your desired band. Clicking ‘OK’ willrender the band, which you can save in GeoTiff, JPEG or other format.124