Construction and Characterization of Merged Atmospheric-Oceanic Temperature Profiles from Dropsondes and AXBT's during the ITOP Project

The Impact of Typhoons on the Ocean in the Pacific (ITOP) was a field campaign aimed at examining the ocean response to typhoons in the western North Pacific. The project was conducted between August 20 and October 20, 2010, during which time two USAF C-130 aircraft deployed six hundred ninety eight dropsondes and approximately 780 Airborne eXpendable BathyThermographs (AXBTs). The C-130 aircraft are equipped with a suite of instruments that includes an Airborne Vertical Atmospheric Profiling System (AVAPS), used for dropsonde deployment. Dropsondes collect high-resolution measurements of pressure, temperature, relative humidity and winds as they descend. The Earth Observing Laboratory (EOL) at the National Center for Atmospheric Research (NCAR) has developed a comprehensive method of quality control (QC) which is applied to all project dropsonde data sets. The QC methods conservatively remove erroneous data, while retaining finer features of the thermodynamic and wind profiles. The QC steps broadly include, examination of the individual raw data profiles for obvious problems; automated processing through NCAR's Atmospheric Sounding Processing Environment (ASPEN) software, which performs smoothing, and removes suspect data points; generation of histograms to evaluate the range and distribution of each parameter; examination of time series plots of each parameter to examine the consistency of soundings launched during each flight, and to show the variability of soundings from different missions; and finally, examination of the each individual quality controlled sounding profile. AXBT sensors measure temperature, as a function of depth, from the sea surface down to approximately 300 meters. These data are a valuable resource for examining upper ocean temperatures and the impact they have on storm initiation and evolution. The AXBT data collected during ITOP do contain known errors and little has been done to establish a comprehensive method of quality assurance. The goals of this research include: 1) Developing a comprehensive quality control scheme for oceanic temperature profiles collected during ITOP, 2) Identifying a sample of collocated, temporary matched, dropsondes and AXBTs and merging the quality controlled data from each to create complete atmospheric-oceanic profiles, 3.) Characterizing the structure of these unique thermodynamic profiles. Preliminary results for each goal will be presented with attention paid to possible future implementation of these techniques in an operational setting.