Algorithm Development for Column Water Vapor Retrieval Using the SAM Sensor

To understand and model the energetics of the Sun-Earth connection, measurements of specific atmospheric molecules are beneficial. Our objective is to formulate an algorithm to derive temporally varying atmospheric water vapor concentrations as a function of altitude, latitude, and longitude from solar irradiance absorption measurements. The Visidyne SAM instrument is used to study the size distribution of cloud particles. By introducing a spectrometer to the SAM instrument, column water vapor values are produced as an additional data product. A new model algorithm was developed and tested against existing algorithms. Through a least-squares analysis, the new algorithm showed an improvement of a factor of up to 23 over the industry standard. A test was also conducted to ascertain which water absorption bandpass produces the least error. Through these tests an improved model algorithm has been produced.