HR: 09:00h
AN: A51F-05    [Abstracts]
TI: Tropical Water distribution A comparison between GPS Occultations and GCMs
AU: * Kursinski, E
EM: kursinsk@atmo.arizona.edu
AF: University of Arizona, 1118 E. Fourth St., Tucson, AZ 85719 United States
AU: Barlage, M
EM: barlage@atmo.arizona.edu
AF: University of Arizona, 1118 E. Fourth St., Tucson, AZ 85719 United States
AU: Mastaler, R
EM: mastaler@atmo.arizona.edu
AF: University of Arizona, 1118 E. Fourth St., Tucson, AZ 85719 United States
AU: Rind, D
EM: drind@giss.nasa.gov
AF: Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 United States
AB: Recently Sherwood et al. (2005) proposed a remarkably simple model for the distribution of relative humidity in the tropics based on stochastic convective moistening followed by simple subsidence warming without additional moisture addition during descent. The model predicts a simple power law dependence with one degree of freedom, the power law exponent, which is equal to the ratio of a drying scale to the time between moistening events. Sherwood et al. showed that the predictions of this simple model are remarkably consistent with the actual tropical relative humidity as captured by GPS radio occultation (RO) and MLS observations. Based on the success of this simple model, and the fact small variations in the temperature versus pressure dependence in near-equatorial environment, we will use tropical GPS RO-derived specific humidities to infer the altitude at which the air parcels were last at saturation, that is the source altitude where the air last left a convective region, and build up a vertical distribution of the tropical convective moisture flux (essentially a profile of moisture divergence) and how it varies regionally and by season. We will then compare results with two climate models, CAM and GISS GCMs in terms of their ability to capture the predicted and observed power law behavior and the time scale ratio exponent as well as their tropical moisture source versus altitude. Sherwood, S., E.R.Kursinski and W. Read, A distribution law for free tropospheric relative humidity, submitted to J. Climate 2005.
DE: 1655 Water cycles (1836)
DE: 3309 Climatology (1616, 1620, 3305, 4215, 8408)
DE: 3333 Model calibration (1846)
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005