Estimation of Model Parameters for Earth Radiation Budget Instruments

Radiation budget instruments scan the earth, creating radiation maps that are interpreted as effective temperature. Then in a sense, these instruments continuously monitor the earth’s radiation budget. Since the measured signals are relatively weak, accurate mathematical modeling is critical to the design process. A mathematical model of the thermal response and the ensuing voltage signal response from a radiation budget instrument has been developed. An important ingredient of an accurate and robust model of the system response is a correspondingly accurate estimation of the model parameters. The main objective of this paper is to describe the procedure and results of the required parameter estimation process. First, the model equations are solved using a finite volume method. A sensitivity study is then performed to indicate the relative importance of the parameters. In order to estimate the best combination of system parameters, a least-squares technique is utilized to minimize the difference between the theoretical model and available experimental data. Fortunately, a statistically significant amount of data for the voltage output of the sensor in question were available. We were able to successfully estimate the model parameters and obtain an excellent fit between the mathematical model and the experimental data on which it was based.