| 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> |
|---|
| 2 | <HTML> |
|---|
| 3 | <HEAD> |
|---|
| 4 | <TITLE></TITLE> |
|---|
| 5 | <META NAME="GENERATOR" CONTENT="Mozilla/3.01Gold (X11; I; SunOS 4.1.4 sun4m) [Netscape]"> |
|---|
| 6 | </HEAD> |
|---|
| 7 | <BODY> |
|---|
| 8 | |
|---|
| 9 | <CENTER><TABLE BORDER=8 CELLSPACING=0 CELLPADDING=0 WIDTH="80%" BGCOLOR="#FFFF00" > |
|---|
| 10 | <TR> |
|---|
| 11 | <TD> |
|---|
| 12 | <CENTER><P><B><FONT COLOR="#FF0000"><FONT SIZE=+1>GEISA-97 Introduction</FONT></FONT></B></P></CENTER> |
|---|
| 13 | </TD> |
|---|
| 14 | </TR> |
|---|
| 15 | </TABLE></CENTER> |
|---|
| 16 | |
|---|
| 17 | <CENTER><P><A NAME="intoduct"></A><B><FONT COLOR="#000000">INTRODUCTION</FONT></B></P></CENTER> |
|---|
| 18 | |
|---|
| 19 | <P><FONT COLOR="#000000">Adequate tools are required to perform reliable |
|---|
| 20 | radiative transfer calculations to meet the needs of communities involved |
|---|
| 21 | in understanding the atmospheres of the Earth and other planets. In particular, |
|---|
| 22 | accurate spectral analyses of Earth or planetary spectra observed by new |
|---|
| 23 | generations of high spectral resolution vertical atmospheric sounders will |
|---|
| 24 | result in an improved knowledge of their atmospheric and surface properties. |
|---|
| 25 | The performance of instruments like AIRS (Atmospheric Infrared Sounder) |
|---|
| 26 | in the USA (JPL, 1991), and IASI (Infrared Atmospheric Sounding Interferometer) |
|---|
| 27 | in Europe (Phulpin et al., 1997), which have a better vertical resolution |
|---|
| 28 | and accuracy compared to presently existing satellite infrared temperature |
|---|
| 29 | sounders, is directly related to the quality of the spectroscopic parameters |
|---|
| 30 | of the optically active atmospheric gases since these are essential input |
|---|
| 31 | in the forward models used to simulate recorded radiance spectra. The ARA |
|---|
| 32 | (Atmospheric Radiation Analysis) group at LMD (Laboratoire de Météorologie |
|---|
| 33 | Dynamique du CNRS, France) developed the GEISA (Gestion et Etude des Informations |
|---|
| 34 | Spectroscopiques Atmosphériques: Management and Study of Atmospheric |
|---|
| 35 | Spectroscopic Information) computer accessible database system (Chedin |
|---|
| 36 | et al., 1982; Husson et al., 1992, 1994), in 1974. This early effort implemented |
|---|
| 37 | the so-called line-by-line and layer-by-layer approach for forward radiative |
|---|
| 38 | transfer modeling action. This activity is of interest to research groups |
|---|
| 39 | involved in direct and inverse radiative transfer studies. </FONT></P> |
|---|
| 40 | |
|---|
| 41 | <P><FONT COLOR="#000000">The role of molecular spectroscopy in modern atmospheric |
|---|
| 42 | research has entered a new phase with the advent of highly sophisticated |
|---|
| 43 | spectroscopic instruments and computers. Retrieval of the concentrations |
|---|
| 44 | of radiatively active molecular species from observed spectra of planetary |
|---|
| 45 | atmospheres using available spectroscopic databases and atmospheric models |
|---|
| 46 | has become fairly routine. The molecular spectroscopist is constantly on |
|---|
| 47 | demand to deliver data that are not only appropriate but essential for |
|---|
| 48 | the analyses of the planetary atmospheric observations. GEISA is dedicated |
|---|
| 49 | to meeting that aim.</FONT></P> |
|---|
| 50 | |
|---|
| 51 | <P><FONT COLOR="#000000">Currently, GEISA is involved in activities, with |
|---|
| 52 | the purpose of assessing the IASI (Infrared Atmospheric Sounding Interferometer) |
|---|
| 53 | measurement capabilities and its own database quality, within the ISSWG |
|---|
| 54 | (IASI Sounding Working Group), in the frame of the CNES (Centre National |
|---|
| 55 | d'Etudes Spatiales, France)/EUMETSAT (EUropean organization for METeorological |
|---|
| 56 | SATellites) European Polar System (EPS), by simulating high-resolution |
|---|
| 57 | adiances and/or using experimental data, as described in Jacquinet-Husson |
|---|
| 58 | et al., 1998a. </FONT></P> |
|---|
| 59 | |
|---|
| 60 | <CENTER><P><A HREF="geisa_index_gs03.html"><IMG SRC="/icons-geisa/prev.gif" BORDER=0 HEIGHT=50 WIDTH=91></A><B><FONT COLOR="#800080"><FONT SIZE=+1>MAIN PAGE</FONT></FONT></B></P></CENTER> |
|---|
| 61 | |
|---|
| 62 | </BODY> |
|---|
| 63 | </HTML> |
|---|
