Radar observations during NAME 2004. Part I: Data products and quality control

During the Extended Observing Period (EOP) of the North American Monsoon Experiment (NAME), which took place during the summer of 2004 in northwestern Mexico, observations were made from three radars – the National Center for Atmospheric Research (NCAR) S-Pol polarimetric radar, and two Mexican weather service (SMN) Doppler radars. These three radars formed a network covering a significant portion of the western slope of the Sierra Madre Occidental (SMO) and adjoining coastal plain, the southern half of the Gulf of California, and the southern tip of the Baja California peninsula during much of July and August – in other words, the central location and time period of the North American Monsoon. Due to difficulties in calibrating the SMN radars and severe blockage by the SMO peaks, a major effort was required to do quality control and correct the data. This involved intercomparison between the SMN radars and the well-calibrated S-Pol radar, and polarimetric-based methodologies to correct beam blockage. The corrected data were then combined into a regional 2-D composites of rainfall and radar reflectivity, which were verified against rain estimates from the NAME Event Raingage Network (NERN) as well as estimates from the Tropical Rainfall Measurement Mission (TRMM) satellite. These composites are available every 15 minutes during the NAME EOP, and provide a useful tool for understanding tropical convective organization and evolution in complex terrain, for verifying satellite estimation of rainfall, and for validating model simulations in this region.