TExas and FLorida UNderflights Experiment (TEFLUN) is the first in a series of TRMM validation experiments using a combination of airborne and surface-based measurements to complement the satellite data. The NASA ER-2 and DC-8 aircraft provide important remotely sensed measurements which provide similar, but higher resolution measurements than the TRMM radar and radiometer measurements. The overarching scientific objective of TEFLUN is to obtain a database suitable for case studies of a few MCSs, early in the TRMM lifetime, from which cloud-resolving models and forward radiative transfer models can be used to understand and improve the performance of the satellite and TRMM Ground Validation (GV) algorithms. TEFLUN-A (1 April to 15 May 1998) was focused on the TRMM Texas GV site, and TEFLUN-B to be conducted from 1 August to 30 September 1998, will be conducted near the Florida GV site near Melbourne. Facilities with both of these experiments include: the NASA ER-2, a cloud microphysics aircraft (the SPEC Lear during TEFLUN-A and UND Citation during TEFLUN-B), a surface network including a multiparameter radar, the NOAA ETL profiler, augmented raingages and disdrometers, and soundings. In addition, the NASA DC-8 will participate in TEFLUN-B.
The focus of this paper will be a summary of highlights from TEFLUN-A and TEFLUN-B (to be conducted in the near future). A key goal in this initial validation experiment is to understand how the vertical structure of precipitation (reflectivity profile, microphysics, etc.) relate to the satellite brightness temperatures, radar reflectivities, and retrieved quantities. During TEFLUN-A, there were 7 science flights with the ER-2 flights, and 8 Lear flights. The ER-2 underflew the TRMM satellite during 5 flights. Various types of precipitation were overflown by the ER-2 and sampled by the microphysics aircraft, although often these were independent of each other. During one of the cases (April 18), the ER-2 was closely coordinated with the Lear, the Houston WSR-88D, and the enhanced surface measurements (NOAA profiler, NOAA X-band polarization radar, raingages, etc.). There were three other interesting cases although not as well coordinated. We will present an example of a coordinated data set with TRMM data (Precipitation Radar (PR) and TRMM Microwave Imager (TMI)) and ER-2 data (EDOP radar and the AMPR radiometer), along with available ground-based measurements and representative microphysical measurements. Preliminary conclusions from this and other data sets will be given.