Other
Scientific paper
Dec 2010
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010agufm.p53b1521p&link_type=abstract
American Geophysical Union, Fall Meeting 2010, abstract #P53B-1521
Other
[3319] Atmospheric Processes / General Circulation, [5405] Planetary Sciences: Solid Surface Planets / Atmospheres, [6295] Planetary Sciences: Solar System Objects / Venus
Scientific paper
We have developed a Venus atmosphere general circulation model (GCM) based on the NCAR CAM Earth climate model. In our simulations we use a simpified thermal relaxation scheme, similar to that used in other Venus GCMs, and linear friction at the lower boundary, with a sponge layer in the upper levels to prevent possible reflection from the upper boundary. We use a high resolution of around 1 degree by 1 degree in latitude and longitude, which allows us to simulate variations on small spatial scales which may be important in Venus' atmosphere. We generate superrotation with mean zonal wind magnitudes comparable with those observed using probes, and around 50 to 60 percent of those measured using cloud-tracking techniques. We find periodic variations in the magnitude of the zonal winds in our simulations at cloud top heights and below, with a timescale of around 10 years. We also find a vacillation cycle in our results, in which the westward winds at cloud level alternate between mid latitude zonal jets and a single equatorial maximum. Analysis of angular momentum transport within our simulations suggests that there is no single simple Hadley cell circulation that transports angular momentum between the surface and cloud levels, but that there is a more complex flow below around 40 km altitude. Observations of Venus' cloud top winds suggest there may be variations in the zonal wind structure over multi-year timescales. Measurements of the atmosphere above the cloud tops also show changes in carbon monoxide content and temperature with timescales of around 10 years. Variations with timescales of tens of years have also been found in the sulphur dioxide content above the clouds within observations over a time interval of 40 years. The origin of the observed multi-year variations is not well known, but it is possible that they could be related to periodic changes in atmospheric dynamics. We investigate the nature of the 10 year oscillations we find in our simulations in order to understand how they occur. We follow the development of the decadal oscillations in the model over time and examine the periods and wavelengths of the simulated eddies. We investigate processes occurring near the lower boundary of the model where the surface-atmosphere interaction feeds angular momentum into the atmosphere. We find that the conditions for symmetric instability are satisfied at low latitudes at the surface. We examine instabilities in the model, including the symmetric instability, and investigate overturning processes near the lower boundary, in order to understand the nature of the long period oscillations.
Covey Curtis
Grossman Allen
Lebonnois Sébastien
Parish Helen F.
Schubert Gerald
No associations
LandOfFree
Investigations of Variability on Multi-Year Timescales in a Venus Atmosphere GCM does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Investigations of Variability on Multi-Year Timescales in a Venus Atmosphere GCM, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Investigations of Variability on Multi-Year Timescales in a Venus Atmosphere GCM will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1499249