Venus Express: One Year in Orbit, Symposium at the 2007 EGU General Assembly Options

[Guest_AlexBlackwell_*]

Forwarding an email that was sent out today by Dmitri Titov, Venus Express PI. Cross reference with this UMSF thread.

Dear Colleagues,

the General Assembly of the European Geophysical Union (EGU) will be held on April 15-20, 2007 in Vienna, Austria. The Symposium PS 2.1 "Venus Express: one year in orbit", included in the science Programme, will be focused on presentation and discussion of the results obtained during the first year of the orbital mission. Please find the description of the Symposium at the end of the e-mail and visit the EGU Web site: http://meetings.copernicus.org/egu2007/ for more details about the Assembly.

We would like to encourage you to take part in the Symposium and to submit contributed abstracts. Please note that the deadline for abstracts submission is January 15, 2007.

Best regards

Dima Titov and Hakan Svedhem,
The Conveners
_________________________________________________
On April 11, 2006 Venus Express-the first European satellite at Venus- was inserted in orbit around the planet and began collecting data. The results of the first year of observations will be presented at the Symposium. The Programme will consist of solicited talks focused on the Venus Express observations and contributed presentations of the preliminary data analysis. The contributions related to the physics of Venus atmosphere, its plasma environment and the surface and based on the analysis of the data from Venus Express and earlier missions, theoretical studies and numerical modelling are highly welcome. Perspectives of the future Venus exploration will be discussed.

Convener : D. Titov (Max Planck Institute for Solar System Research, Germany) Co-convener : H. Svedhem (ESA/ESTEC, The Netherlands)

[ollopa]

This discussion is more noise than information. Can I suggest Nils Muller's astonishing extraction algorithm as a way of getting at what lies beneath? Anyone who wonders why VEX has taken so long to release product should read the Mueller paper (summary below). This young man and his colleagues have slaved for month after month to extract surface emissivity data out of the scrambled VIRTIS data. Their first "picture" (yes, one) was displayed at AGU last month. Mueller was the proudest planetary researcher I have ever met, bar none. Does he care he's not a daily POD?

ESA's non-core budget was evicerated several years ago to repay (IIRC) seven BILLION euro to industry. If that debt of honour was not repayed there would have been no ESA. P.R. was a major victim. Vote now: PODs or missions?

Individual MEX PI's such as Bibring and Neukem use their own precious time and budgets to turn up at virtually every planetary science meeting around the globe. I have found them willing to share information at a level that matches or exceeds the undoubted openness of their U.S. colleagues.

I am not associated with ESA, but I believe their public outreach staff do a very credible job in often straitened circumstances. My in-box tells me that ESA's press office has issued seven press releases in the first week of 2007 - four on Friday alone. I am aware that ESA is currently exploring novel alternative ways of structuring its public outreach with the help of member governments, but there's a limit to what you can do in-house if the-powers-that-be insist on putting research ahead of PODs.



P42A-07

Algorithm for Extraction of Surface Emissivity in the Context of VIRTIS on Venus Express

* Mueller, N (nils.mueller@dlr.de) , DLR Institute for Planetary Research, Rutherfordstr. 2, Berlin, 12489 Germany
Jorn, H (joern.helbert@dlr.de) , DLR Institute for Planetary Research, Rutherfordstr. 2, Berlin, 12489 Germany
Hashimoto, G (george@kobe-u.ac.jp) , Graduate School of Science and Technology, Kobe University, Nada-ku, Kobe, 657-8501 Japan
Marinangeli, L (luciam@irsps.unich.it) , IRSPS, Universita d Annunzio, Viale Pindaro, 42, Pescara, 65127 Italy
Piccioni, G (piccioni@rm.iasf.cnr.it) , INAF - IASF Roma, Via del Fosso del Cavaliere 100, Roma, 00133
Drossart, P (Pierre.Drossart@obspm.fr) , LESIA - Observatoire de Paris, 61 avenue de l observatoire, Paris, 75014 France

Venus nightside multispectral images aquired by VIRTIS contain information of surface emissivity at wavelengths close to 1 micron. This information is relayed by thermal emissions of the surface escaping to space through the NIR spectral 'windows' in the atmosphere. On its way through the atmosphere the thermal radiation is modified by scattering and absorption by clouds. Variations in the optical thickness of the clouds modulate the spatial distribution of upwelling radiation. Multiple reflections between surface and clouds generally wash out image contrast from surface emissivity. We present an algorithm to extract surface emissivities by separating atmospheric influences from the images inside the spectral windows at 1.02, 1.10 and 1.18 micron. The necessary processing steps detailed are: 1) Removal of scattered sunlight 2) Binning of appropriate images inside the window spectral ranges 3) Correction of limb darkening 4) Removal of contrast due to attenuation by clouds 5) Removal of contrast due to surface temperature 6) Correction for multiple cloud-surface-reflections For a first quick guess on general trends of emissivity with respect to geological circumstances this algorithm is applied with several simplifications and ad-hoc assumptions. This simple model assumes the atmosphere of Venus to be one horizontally homogenous layer with spatial variation of transmittance allowing for direct inversion of the data. For an improved estimation of surface emissivity tabulated results from previous forward modeling of radiative transfer are used for steps 2) to 6). With this approach the accuracy of a detailed modeling of the atmosphere of Venus is combined with the speed and traceability of the step-by-step inversion of radiance data using the simplified model.