Microwave atmospheric sounder for earth limb observations from space

Attention is called to the need for global sets of atmospheric data in modern atmospheric research as input to model calculations. It is only by means of space-borne remote sensing observing techniques tnat such data sets can be obtained. These sensors possess the required global coverage and have a high repetition rate. The radiation emanating from the atmospheric limb in the frequency range from 60 to 200 GHz is to be measured by the Microwave Atmospheric Sounder (MAS). The MAS will be part of the fourth mode of the Microwave Remote Sensing Experiment. The mission objectives are described, and an account is given of the MAS system and the modifications of the MRSE that will be necessary. The MAS will operate in two submodes, that is, the pointing mode and the elevation scan mode. In the second, the antenna axis scans with a constant velocity of 1.25 deg/s through the elevation angle, which ranges from 10 deg to 16 deg. The azimuth angle here is fixed at 0 deg.