Abstract
Relative humidity profile estimation method with AIRS (Atmospheric Infrared Sounder) data by means of SDM (Steepest Descend Method) with the initial value derived from LED: Linear Estimation Method is also proposed. Through experiments, it is found that there is almost 15 (%) of relative humidity estimation error. Therefore, it can be said that the relative humidity is still tough issue for retrieval. It is also found that the estimation error does not depend on the designated atmospheric models, Mid-Latitude Summer/Winter, Tropic. Even if the assigned atmospheric model is not correct, the proposed SDM based method allows almost same estimated relative humidity. In other word, it is robust against atmospheric model.
Highlights
Vertical profiles of air-temperature and relative humidity (Water vapor) can be estimated with satellite based Infrared Sounder data [1]
To avoid this situation of which the solution is falling in local minima and accelerate the convergence through giving initial value which is derived from a Linear Estimation Method (LEM)
Levenberg Marquardt (LM) method minimizes the difference between AIRS data derived radiance, R0i and estimated radiance, Ri based on atmospheric model with the parameters of air-temperature and relative humidity
Summary
Vertical profiles of air-temperature and relative humidity (Water vapor) can be estimated with satellite based Infrared Sounder data [1]. There is least square based conventional method for estimation of vertical profiles of air-temperature and relative humidity. SDM based optimization method shows relatively good accuracy, it takes a comparatively large computer resources and it is falling in local minima, not in the global optimum To avoid this situation of which the solution is falling in local minima and accelerate the convergence through giving initial value which is derived from a Linear Estimation Method (LEM). Air-temperature and relative humidity can be estimated using absorption characteristics of carbon dioxide and water vapor contents in the atmosphere. Estimation accuracy of air-temperature and relative humidity at around tropopause is not good enough
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