Tropical wind-profiling radars: High-resolution, multi-purpose, and multi-scale observations

The Trans-Pacific Profiler Network (TPPN) was established across the Pacific basin during the TOGA decade (1985-1994) and was designed to complement the oceanic and near-surface TAO buoy observations. The network consists of 50-MHz profilers at Piura, Christmas Island, and Biak together with 915-MHz profilers at San Cristobal, Christmas Island, Tarawa, Nauru, Manus, and Biak. Other wind profilers have at times been deployed in the tropical Pacific by the NOAA Aeronomy Lab for special field programs. The 50-MHz profilers primarily observe winds from 1.5 km to 15 km with 1 km resolution. The 915-MHz wind observations typically extend from a few hundred meters above the surface to about 5 km with 100 to 500 m resolution. The 915-MHz profilers can also observe falling hydrometeors, and processing techniques have been developed which allow the determination of precipitation characteristics. The TPPN profilers operate continuously, with post-processed winds usually generated at half-hourly resolution. These profilers have often been collocated with surface met and balloon sounding in "Integrated Sounding System" (ISS) sites, or with a variety of radar- and surface-based precipitation measuring systems for detailed precipitation studies.

Real-time observations from several TPPN sites are routinely placed on the GTS for inclusion in global analysis and modelling products. Their inclusion in a TOGA-COARE reanalysis project improved budget calculations of rainfall rates. TPPN data have been used in a variety of research studies: interannual variability and the seasonal cycle of both the deep troposphere over the Central Pacific and of the lower troposphere over the East Pacific cold tongue; wave activity on a variety of scales at several locations in the Pacific; the diurnal cycle over both the western and eastern equatorial Pacific; and the distribution of precipitation over the west Pacific warm pool, the cold tongue, and the eastern ITCZ. This presentation will give a brief overview of the various configurations and time periods in which the profilers have operated, present some of the wide-ranging results that have come out of the profiler data, often with the support of other atmospheric and oceanic data sets, and offer some ideas for how the usefulness of these data can be expanded in the future.