Estimation of accuracy obtained from automatic picture transmission of meteorological satellite NOAA comparing with high resolution picture transmission data

In many fields, APT image data has been put to practical use. However, several problems are left in using APT data intensively. To establish a data calibration procedure, the authors examined the level accuracy of APT by comparing APT data with AVHRR data which becomes an origin where the APT is generated. Values of all data in the specified region of the scanning lines were examined relative to each other, to plot a distribution chart. As a result, some aberrations in the gray scale value of APT versus HRPT count value were found. Taking the aberration into account, the authors have established conversion algorithms from the channel 2, visual data to albedo and from the channel 4, infrared data to brightness temperature. They discuss the measurement errors caused by the conversion. A standard deviation of 1.4 degC at 5 degC in brightness temperature and a standard deviation of 1.5% at 30% in albedo are obtained