RSMA WORKING GROUP

(Remote Sensing of Middle Atmosphere)

CALL FOR PARTICIPATION IN THE ACTIVITIES

(Chairman: Prof. Dr. Yu. Timofeev, tim@troll.phys.spbu.ru)


Intercomparison of non-LTE population models and radiative transfer codes

INTRODUCTION

Satellite remote sensing methods are widely used for the investigation of temperature, gas and aerosol composition and the dynamics of the middle atmosphere. The most widely used are the measurements of the atmospheric radiance with the limb geometry (e.g. LIMS, SAMS, ISAMS, CIRRIS, CLAES, CRISTA and other instruments). In the nearest future new satellite experiments are planned in the infrared region - SABER, MIPAS, HIRDLS, SWIRLS, TES.

The interpretation of the limb infrared radiance measurements at large tangent altitudes requires accounting for the nonlocal thermodynamic equilibrium (non-LTE). At present, different approaches are developed to the solution of inverse problems (with respect to temperature and gas composition) under the non-LTE conditions which utilize different amount of a priori information. Nevertheless, all approaches require calculations of the non-LTE radiance. In a number of approaches the kinetic models of nonequilibrium processes are incorporated.

For many satellite experiments, the measurement data of different levels are a public domain or are distributable by requests among the scientific community.

Interpretation of the experimental data by large number of different scientific teams requires the basis for the intercomparison of obtained results. Such intercomparison, in turn, is necessary for the estimation of quality and reliability of the final results.

The present program of the WG RSMA focuses on the problem of the interpretation of the infrared limb radiance spectral measurements by the instruments of medium and high spectral resolution for the non-LTE case.

The main goal of the study is to give the range of uncertainties in calculating atmospheric radiance accounting for nonlocal thermodynamic equilibrium conditions on the basis of intercomparison activities.

Intercomparison activities are planned in two parallel and coordinated streams:

The activities will be performed by two corresponding subgroups working in close cooperation. THE RESEARCHERS ARE INVITED TO PARTICIPATE IN ANY OF THE SUBGROUPS OR IN BOTH.