Scaling method of foundation microwave radiometer

Abstract

The invention relates to a scaling method of a foundation microwave radiometer. The scaling method comprises: obtaining voltage values output through each channel in different attenuation values, calculating corresponding equivalent brightness temperature values through attenuation values, calculating system non-linear factors and noise source injection noises according to corresponding relation between each equivalent brightness temperature value and the output voltage of each channel, and completing preliminary scaling; according to sounding profile data matching with time and place, establishing a corresponding relation of atmosphere optics thickness and atmosphere quality, substituting scaling parameters, obtaining a scaling relation curve, determining the scaling parameters according to the scaling relation curve; observing cold air and cold air coupling noises at each attenuation value, obtaining voltage values output through each channel at different attenuation values and fitting the attenuation values and the voltage values; calculating the equivalent noise temperature when an antenna aligns with the cold air through the relation of the attenuation values and the output voltage values of the attenuator, and determining the brightness temperature values corresponding to the cold air observed by the foundation microwave radiometer in different time and places.

Description

technical field [0001] The invention relates to a calibration method, in particular to a ground-based microwave radiometer calibration method. Background technique [0002] The K-band microwave radiometer is a passive microwave remote sensor that can penetrate clouds and rain areas, and can be used for all-day and all-weather observation of global atmospheric humidity, water vapor content, rainfall and other meteorological data. Calibration technology is a key technology in microwave radiometer design. Due to the special working environment of the ground-based radiometer, affected by the attenuation of the atmosphere, there is no cosmic cold space background on the ground to use, and the reference source is a high-temperature source compared with the brightness temperature of the atmospheric radiation. error, so it is critical to determine the dynamic response relationship for the full observation range. [0003] At present, the high and low temperature two-point linear ca...

AI Technical Summary

Problems solved by technology

The four-point nonlinear calibration method based on the liquid nitrogen cooling calibration blackbody as one of the reference sources takes into account the nonlinear characteristics of the detector tube, but the selected reference source temperature is higher than the observed atmospheric radiation, and the calibration brightness temperature value is determined by The calibration curve is obtained by extrapolation, the introduced error is uncertain, and the more obvious the nonlinearity, the greater the error of the calibration brightness temperature value

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