Satellite-based columnar water vapor retrieval with the multi-spectral thermal imager (MTI)

The Multi-spectral Thermal Imager (MTI) has three near-infrared bands (E, F, and G) within the 850-1050-nm spectral range that are used for the columnar water vapor (CWV) retrieval using the continuum interpolated band ratio (CIBR) and the atmospheric precorrected differential absorption (APDA) methods. The retrieved CWV amounts are compared with the aerosol robotic network (AERONET) measurements at the Oklahoma Atmospheric Radiation Measurement (ARM) program and the Stennis Space Center sites. We find no significant difference in the accuracy of the two tested methods. However, there is a considerable difference in the root mean square error (RMSE) for the CWV retrieval over the Oklahoma ARM and the Stennis Space Center sites. The overall RMSE of the MTI CWV retrieval is found to be 13% to 14%. The error is reduced to 11% to 12% for CWV amounts larger then 1 g/cm².