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The Multichannel Visible and Infrared Scan Radiometer (MVISR) is carried aboard the FY-1C polar-orbiting satellite. This satellite operates in a near-polar sun synchronous orbit. The MVISR has:
First the MVISR data is extracted from the raw High Resolution Picture Transmission (CHRPT) telemetry data using chrptin. chrptin is designed to extract MVISR data from the CHRPT data collected with the TeraScan data acquisition system. The function converts the output to radiometric temperatures. For visible and near IR channels the results are percent albedo; for the thermal IR channels the results are temperature in degrees. Occasionally lines are missing from the CHRPT telemetry stream; chrptin can also fix missing lines by duplicating nearby lines.
Small errors in the spacecraft clock and horizon tracker produce small errors (1 to 10 km) in the satellite location. For many applications these errors are not important and correcting this error can be ignored. For many studies, however, precise locations in small areas are required. To correct these errors, navigate the ingested data with the functions navbox2 and nav2. navbox2 selects boxes that contain iregular land/water boundaries, and nav2 correlates image data with those boundaries.
The refy2 function computes the water column turbidity index, normalized difference vegetation index (NDVI), reflectance for channels 1 and 2, and aerosol optical thickness.
The last step in the chain is to orient the data to a master using the function fastreg. You can view the dataset any time after ingest (chrptin) using the TeraVision program.
Last Update: $Date: 2001/08/23 18:03:14 $