A study of the solar radiation effect on the 4.3-mu m channels of the High-Resolution Infrared Radiation Sounder

Measurements of infrared radiation from the National Oceanic and Atmospheri c Administration series of satellites are used to retrieve atmospheric temp erature, moisture, and ozone. It is well known that the measurements from t he 4.3-mum channels of the High-Resolution Infrared Radiation Sounder (HIRS ) are affected by solar radiation. These effects can have an important effe ct on retrieved parameters and have caused difficulties in the use of the h igher-peaking shortwave channels for many applications. In the channels tha t respond to the upper atmosphere, this effect can reach 2 K for high solar angles. In this paper, a regression procedure is used on nighttime data to determine a relationship between these channels and the other channels of the HIRS and the Microwave Sounding Unit of the Television and Infrared Ope ration Satellite Operational Vertical Sounder. This regression then is appl ied to daytime data to study the effect of solar radiation on these channel s. This paper provides a method for estimating and partially removing these effects.