![]() This method is tested with dual-Doppler radar data from the observation of the frontal convective part of a West-African squall-line on 22 June 1981. provided that an initial value is known, the three-dimensional fields of pressure and temperature are deduced through adding, at each altitude, these constants to the relative pressure and temperature fields. A simplified thermodynamic equation is used to calculate the vertical gradients of the missing pressure and temperature constants. Test and evaluate dual-pol PAR prototypes.A new method is proposed to determine completely the thermodynamic fields from the relative pressure and temperature perturbations, retrieved from the processing of multiple-Doppler radar data through the equations of motion.Determine specifications for a dual-pol Phased Array Radar (PAR) and evaluate various design issues.Examine impacts of dual-pol radar observations on hydrologic simulations to better predict excessive rainfall and flooding.Examine the performance of a dual-pol partial beam blockage correction algorithm on radar quantitative precipitation estimation,.Develop approaches for incorporating information inferred from dual-pol radar about the observed precipitation back into numerical weather prediction models. ![]() Examine dual-pol signatures that can help NWS forecasters anticipate the development of hazardous weather such as large hail and downbursts.Identify consistent and/or reliable dual-pol signatures associated with various precipitation processes in winter storms, such as the formation of ice pellets or large snowflakes.Improve a dual-pol “hydrometeor classification algorithm” that combines dual-pol radar observations with temperature information from numerical weather prediction models to determine what type of precipitation is being observed.Moreover, the correlation between the two returns is very different in cases of precipitation compared to non-precipitation returns.ĭual-pol researchers at NSSL are endeavoring to: For example, the corresponding cross-sections give forecasters a measure of the size and shape of the object, which can be used to infer more information about the types of objects that scattered the waves, like whether the radar is observing rain or snow, or big raindrops versus small raindrops. As these perpendicular fields scatter, or “bounce,” off of an object and are received back at the radar, a computer program processes information about the horizontal and vertical properties of the particles. With dual-pol technology, the picture becomes two-dimensional because the radar sends both horizontally and vertically polarized electromagnetic waves. This one-dimensional picture makes it difficult to tell the difference between precipitation types. Single-polarization Doppler radars, including the NOAA radars before the dual-polarization upgrade, typically transmit horizontally polarized electromagnetic waves, which only give a measure of the horizontal dimension of precipitation particles, like snow, ice pellets, hail and rain. A computer processes the returned signals and, through algorithms, can identify kinds of particles the radar “saw,” including how quickly the particles are moving toward or away from the radar (i.e., the Doppler effect). Some of this energy is scattered by particles or objects in the atmosphere and returns back to the radar antenna. ![]() Radars send out short pulses, also known as bursts, of electromagnetic energy. The upgraded radars also help tell the difference between smoke, birds, bats and bugs. The upgraded radars offer 14 new radar products to better determine the type of precipitation, the intensity and how much precipitation may fall in addition to confirming if a damaging tornado is occurring during a storm. ![]() Since the completion of the upgrade to dual-pol, the NOAA NWS Warning Decision Training Division has provided timely and relevant training to all NWS forecasters who use the technology. JPOLE proved that significant improvements in rainfall estimation, precipitation classification, data quality and weather hazard detection were possible using polarimetric radar and provided supporting evidence for upgrading the entire NEXRAD fleet to dual-pol capabilities. During JPOLE, NSSL scientists aided in data interpretation as it was delivered in “real-time” to NWS forecasters and other users. In 2002-2003, NSSL conducted the Joint Polarization Experiment (JPOLE) to demonstrate the operational capabilities of the prototype dual-pol WSR-88D radar. A quick glance at the new dual polarization technology added to the national weather radar network. ![]()
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