Rapid Variability of Water Vapor Abundance in the Venus Mesosphere

Details Rapid Variability of Water Vapor Abundance in the Venus Mesosphere Rapid Variability of Water Vapor Abundance in the Venus Mesosphere

Sep 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006dps....38.2608g&link_type=abstract

American Astronomical Society, DPS meeting #38, #26.08; Bulletin of the American Astronomical Society, Vol. 38, p.525

Astronomy and Astrophysics

Astronomy

Scientific paper

We present the first detections of the water vapor ground-state rotational transition (at 556.9 GHz) and the 13CO(5-4) rotational transition (at 550.9 GHz) from the atmosphere of Venus, obtained with the Submillimeter Wave Astronomy Satellite (SWAS). These submillimeter transitions originate primarily from the 70-100 km altitude range, within the Venus mesosphere. Observations were obtained in December 2002, and January, March, and July 2004, coarsely sampling one Venus diurnal period as seen from Earth. Complementary observations of the 12CO(2-1) rotational transition (at 230.5 GHz) were obtained concurrently with the Submillimeter Array (SMA) to help constrain global atmospheric parameters.
The water vapor absorption line depth shows large variability among the four observing periods, with strong detections of the water line in December 2002 and July 2004, and no detections in January and March of 2004. Using a multi-transition inversion algorithm (combining temperature, carbon monoxide, and water profile retrieval under some constraints), we retrieved or found upper limits for the globally averaged mesospheric water vapor abundance for each period, finding variability over at least two orders of magnitude. The results are consistent with both temporal and diurnal variability, but with short-term fluctuations clearly dominating.
The observations from December 2002 detected very rapid changes in water vapor abundance. Over five days, a deep ground-state water absorption feature consistent with a water abundance of 4.5±1.5 ppm suddenly gave way to a significantly shallower absorption, implying a decrease in the water abundance by a factor of nearly 50 in less than 48 hours. In 2004 similar changes in water vapor abundance are seen between the March and July SWAS observing periods, but variability on timescales of less than a week was not detected.
M.A.G. gratefully acknowledges support from NASA contract NAG5-7946. G.J.M., V.T., E.A.B, and B.M.P. were supported by NASA contract NAS5-30702.

Affiliated with

Also associated with

No associations

Rating

Rapid Variability of Water Vapor Abundance in the Venus Mesosphere 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 Rapid Variability of Water Vapor Abundance in the Venus Mesosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rapid Variability of Water Vapor Abundance in the Venus Mesosphere will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-999465