Air Temperature Retrieval By Using FY Geosynchronous Satellite Data

This paper is mainly based on the thermal infrared remote sensing and the temperature inverted researchs,11μm and12μm thermal infrared band and temperature are closely related, and temperature change by latitude and date obviously, then proposed a new inverted temperature method. And apply it at14and2, and the summer’ and winter’ temperature will be inspected by day and site. This form of the algorithm is simple and less demanding, can be used on other times and satellites.1) present a new method of air temperature retrieval:using the original FY thermal infrared data (T11μm and T12μm brightness temperature) and Julian day and location parameters (longitude, latitude, elevation) to get the air temperature, specifically air temperature is retrievaled by the initial guess regression equation and bias correction equations.2) one-day data to obtain:employing ENVI+IDL programs to read geostationary satellite FY-TBB (11μm), IR2(12μm), IR3(7μm), IR4(3.75μm), VIS (0.75μm) band images and weather observation data files. According to the weather site, extracting the situation geostationary satellite TBB (11μm), IR2(12μm), IR3(7μm), IR4(3.75μm), VIS (0.75μm) data at the corresponding latitude and longitude location and which are combinated with the meteorological stations, month, day, time and site number, longitude, latitude, elevation, Julian day calculated by the month and date, thus forming all the necessary data at a site. other sites datas in single day are combinated by this method.3) the guess is calculated by using guess equation of each site day by day and the bias of which is calculated to measured temperature value. then checking the properties between the guess and the measured values. a text file will have been generated from year-round daily text file data generatedat site by using the IDL programms.4) extraction of high, medium and low latitudes on a typical site. View guess and measured temperature, the relationship of the bias betwwen latitude and date, and the establishment of deviation equation with latitude and date, obtain the relationship of the coefficient of the bias equation at high, medium and low latitudes with latitude, then get the bias expression at other latitudes.5) using the guess values and the biases to retrieval the air temperature, to extract the summer、winter classic single-day data, and high、medium and low latitude site data for accuracy testing.