Moderate-resolution Imaging Spectroradiometer (MODIS) and the SPOT-5 Satellite Images Characteristics - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 211

APPENDIX (A-1)
Moderate-resolution Imaging Spectroradiometer (MODIS) and the SPOT-5
Satellite Images Characteristics
MODIS (Moderate-resolution Imaging Spectroradiometer)
MODIS is an extensive program using sensors on two satellites that each provide complete daily
coverage of the earth. The data have a variety of resolutions; spectral, spatial and temporal. The
MODIS web site, http://modis.gsfc.nasa.gov/index.php , is a good place to begin learning about this
important program. This site has links to the Atmospheres, Land and Oceans groups of MODIS.
Because the MODIS sensor is carried on both the Terra and Aqua satellites, it is generally possible to
obtain images in the morning (Terra) and the afternoon (Aqua) for any particular location. Night time
data are also available in the thermal range of the spectrum. You should consider time of day when
ordering a scene for a specific day.
Daily MODIS Scenes - Level 1
Individual daily MODIS scenes, MODIS Level 1 products, can be obtained for any part of the earth,
every day, since February 2000. These files are in the Geographic projection and have a spatial
resolution of 1 km. There are 36 bands of image data interspersed through 85 total bands of
information in the file. The data are digital numbers in 16 bit unsigned integer format. These data
should be converted to radiance values, surface reflectance values, and/or brightness/temperature
values before performing any analysis. Terra file names for the complete file begin with
M O D021KM. Aqua file names begin with M Y D021KM.
Alternatively daily scenes at 500 m resolution can be obtained which would include the first 7 bands
of data, or the first two bands of data at 250 m resolution. The Terra names for these are MOD02HKM
and MOD02QKM respectively.
MODIS Products - Level 2
Product data are generally provided in the sinusoidal projection. Below are descriptions of the surface
reflectance and vegetation products, but many more products are available.
MODIS Surface Reflectance Products; MOD 09 - Surface Reflectance; Atmospheric
Correction Algorithm Products
The MODIS Surface-Reflectance Product (MOD 09) is computed from the MODIS Level 1B land
bands 1, 2, 3, 4, 5, 6, and 7 (centered at 648 nm, 858 nm, 470 nm, 555 nm, 1240 nm, 1640 nm, and
2130 nm, respectively). The product is an estimate of the surface spectral reflectance for each band as
it would have been measured at ground level if there were no atmospheric scattering or absorption.
The correction scheme includes corrections for the effect of atmospheric gases, aerosols, and thin
cirrus clouds; it is applied to all noncloudy MOD 35 Level 1B pixels that pass the Level 1B quality
control. The correction uses band 26 to detect cirrus cloud, water vapor from MOD 05, aerosol from
MOD 04, and ozone from MOD 07; best-available climatology is used if the MODIS water vapor,
aerosol, or ozone products are unavailable. Also, the correction uses MOD 43, BRDF without
topography, from the previous 16-day time period for the atmosphereBRDF coupling term. The
following are examples of the
MOD09GQK - MODIS Surface Reflectance Daily L2G Global 250m
This file has a spatial resolution of 250 m and contains two bands of spectral data centered at 645 nm
and 858 nm. There are also three bands of additional information on band quality, orbit and coverage,
and number of observations.