Comparisons of temperature profiles from nearby GPS radio occultations over a high wave activity region

D. LUNA1, P. ALEXANDER1, A. DE LA TORRE1, P. LLAMEDO1, T. SCHMIDT2 AND J. WICKERT2

Montreal, Canada

Congreso; COSPAR 2008; 2008

The GPS (Global Positioning System) Radio Occultation (RO) technique has global coverage and is capable of generating high vertical resolution temperature profiles of the troposphere and lower stratosphere with sub-Kelvin accuracy and long-term stability, regardless of weather conditions. Fluctuations in these profiles give information about gravity waves. COSMIC is a six-satellite RO constellation, launched in April 2006 that performs a larger amount of occultations per day than any previous mission. In this work, we take advantage of the anomalous high density of COSMIC occultation events at the eastern side of the highest Andes Mountains during the initial mission months. This region is well-known for its high gravity wave activity. From 669 profiles examined in this zone, 50 pairs of them, occurring within 2 hours and 200 km of one another, were found. We compared these nearby cases. One particular pair has shown a significant difference in the wave energy content associated to each profile. Numerical simulations with a mesoscale model were performed, in order to understand this discrepancy. We also intend to draw information on the difference between real and detected wavelengths from the RO observational geometry. This kind of studies may help to better understand the GPS RO retrieval process and its advantages and drawbacks in describing atmospheric temperature.