Conference
Martian mesospheric CO2 clouds: OMEGA and HRSC data, the LMD-MGCM and possibility for mesospheric convection
| العنوان: | Martian mesospheric CO2 clouds: OMEGA and HRSC data, the LMD-MGCM and possibility for mesospheric convection |
|---|---|
| المؤلفون: | Määttänen, Anni, Montmessin, Franck, Gondet, Brigitte, Hoffmann, Harald, Scholten, Frank, González-Galindo, Francisco, Spiga, Aymeric, the, Martian-CO2 cloud Team |
| سنة النشر: | 2010 |
| المجموعة: | German Aerospace Center: elib - DLR electronic library |
| مصطلحات موضوعية: | Institut für Planetenforschung |
| الوصف: | We will present 3 Martian years (Mars Years 27-29) of high-altitude CO2 cloud data from MEx/OMEGA and se- lected results from Mex/HRSC. OMEGA observed these clouds on 51 and HRSC in 28 orbits with 11 simultaneous observations. The 3-year dataset shows that the cloud activity starts latest at Ls=0° (with the earliest occurrence ob- served at the end of MY 29 at Ls=330°), and continues until Ls=60° when ceasing for a period before the summer solstice. The activity starts again at or after Ls=90°, and after Ls=120° the equatorial clouds are nearly absent in our dataset. Three cases of midlatitude autumn/winter clouds have been observed: one in the northern hemisphere and two in the southern. The spatial distribution of the clouds is limited in a latitude range of 20°S-20°N (with the exceptions of the midlatitude clouds) and a longitude range -120 – 30°E (3 exceptions). The HRSC stereo observations enable accurate cloud altitude measurements, yielding values between 60 and 85 km (+/-2 km) for the near-equatorial clouds. The clouds speeds, related to the prevailing east-west winds, range from 15 to 107 m/s (+/-15 m/s). Two cloud shadow observations show that cloud opacities can go up to =0.6 and the cloud particle effective radii are mainly in the range reff=1-2 µm. A comparison with the LMD Mars Global Climate Model shows a good agreement between the model-predicted winds and those observed by the HRSC. The LMD-MGCM predicts a strong diurnal variation of temperature at the cloud observation altitudes due to the propagation of the diurnal thermal tide. The coldest temperatures in the near-equator cloud altitude range (60-85 km) are observed towards the end of the afternoon, whereas the warmest temperatures are found in the early morning hours. Most of the observed clouds are cirrus-type, filamented clouds, but in some OMEGA observations the clouds exhibit round, clumpy structures that have been suggested to be of convective origin. We assess the plausibility of the hypothesis of mesospheric convection in light of the ... |
| نوع الوثيقة: | conference object |
| اللغة: | unknown |
| Relation: | Määttänen, Anni und Montmessin, Franck und Gondet, Brigitte und Hoffmann, Harald und Scholten, Frank und González-Galindo, Francisco und Spiga, Aymeric und the, Martian-CO2 cloud Team (2010) Martian mesospheric CO2 clouds: OMEGA and HRSC data, the LMD-MGCM and possibility for mesospheric convection. EGU General Assembly 2010, 2010-05-02 - 2010-05-07, Vienna, Austria. |
| الاتاحة: | https://elib.dlr.de/67436/ http://meetingorganizer.copernicus.org/EGU2010/oral_programme/2113 |
| رقم الانضمام: | edsbas.BFE59195 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |