Tropical Rainfall Rate Relations Assessments from Dual Polarized X-BAND Weather Radars

As part of the Puerto Rico Weather Radar Network (PRWRN), the TropiNet consists of three X-band Dual Pol Doppler radars which are strategically located in the west coast of Puerto Rico. Each node of the network is capable of providing different polarimetric products such as reflectivity, differential reflectivity, propagation differential phase shift, and velocity, among others. These radars focus their observation in the lower portion of the atmosphere, overcoming coverage limitations from the NEXRAD radar located a 100 Km from the area under study. A long term goal of the PRWRN is to consistently provide in a daily basis an accurate forecast to protect the life and property of the people from the west coast. This network has the capability to densely monitor and study the different atmospheric events which are frequently developed at the lower atmosphere of western Puerto Rico. The high spatial and temporal resolution is expected to provide essential data to better understand the tropical weather dynamics in a mountanouis terrain which characterizes the topography of the Island. This is a particularly challenging task for meteorologists and it is expected that a significant improvement in forecast of rain can be achieved helping warning times of events which can cause devastating results in a matter of minutes. Today, it is well known that dual polarized weather radar provide valuable information for hydrological and meteorological studies significantly improving forecast models that can lead to potentially save the life and property of the people affected by severe weather events. The west area of Puerto Rico is subject to sudden flooding's, due the extreme rainfall events, some of which the National Oceanic and Atmospheric Administration (NOAA) National Weather Service (NWS) NEXRAD (Next-generation Radar) radar have limited coverage due to the distance between the west coast and the location of the S-band long-range radar. Most X-band radars offer improved spatial and time resolution and less problematic ground clutter with relatively small size, which makes them a preferable tool for polarimetric radar applications. In this particular work, the propagation specific differential phase shift (KDP), and the differential reflectivity (ZDR) are used to develop an algorithm that will provide a more accurate and reliable estimation of precipitation than the current technology. The polarimetric products from the X-band radar, together with observations from a Parsivel disdrometer, will be used to develop this relationship. The results obtained in this work will lead to the first rain rate relationship for Puerto Rico using polarimetric products derived from X-band radars. This low atmosphere data will complement current results obtained with NEXRAD for the upper atmosphere.