A Minimized Mutual Information retrieval for simultaneous atmospheric pressure and temperature

TL;DR

This paper introduces a novel method for simultaneously retrieving atmospheric pressure and temperature on Mars using a spectrometer, employing minimized mutual information and information content analysis to optimize micro-window selection.

Contribution

It presents a new retrieval model that accurately determines pressure and temperature without prior assumptions, utilizing minimized mutual information and a micro-window selection strategy based on information content.

Findings

Successful simultaneous retrieval of pressure and temperature from spectroscopic data

Use of minimized mutual information improves micro-window selection

Validation of the method with theoretical analysis and comparisons

Abstract

The primary focus of the Mars Trace Gas Orbiter (TGO) collaboration between NASA and ESA is the detection of the temporal and spatial variation of the atmospheric trace gases using a solar occultation Fourier transform spectrometer. To retrieve any trace gas mixing ratios from these measurements, the atmospheric pressure and temperature have to be known accurately. Thus, a prototype retrieval model for the determination of pressure and temperature from a broadband high resolution infrared Fourier Transform spectrometer experiment with the Sun as a source on board a spacecraft orbiting the planet Mars is presented. It is found that the pressure and temperature can be uniquely solved from remote sensing spectroscopic measurements using a Regularized Total Least Squares method and selected pairs of micro-windows without any a-priori information of the state space parameters and other constraints. The selection of the pairs of suitable micro-windows is based on the information content analysis. A comparative information content calculation using Bayes theory and a hyperspace formulation are presented to understand the information available in measurement. A method of minimization of mutual information is used to search the suitable micro-windows for a simultaneous pressure and temperature retrieval.