Meteorological Radar

Meteorological radar uses information from the amplitude, and phase, at different polarization states of the scattered electromagnetic wave to reveal relevant properties of clouds and precipitation for weather monitoring and forecasting in short time the behavior of hazardous storms. Since mid-1950s, many countries have deployed networks of meteorological radars: nowadays, stand-alone radars or networks of meteorological radars are key tools for most of national weather services. The last couple of decades have been very exciting time for the fields of weather radar science and technology. The major technological advances include operational adaptation of dual-polarization technology and large-scale deployment and upgrades with meteorological services, introduction of the concept of dense network of radars through the Collaborative Adaptive Sensing of the Atmosphere (CASA) project, and space-borne weather radars. This article starts with a simple introduction of the meteorological radar basics, and then describes one of the most important application of weather radars worldwide, namely, the quantitative precipitation estimation. Subsequently, examples of radar observations of winter storms and summer convective storms are presented, followed by one of the popular applications used by operational forecasters, namely, nowcasting. Criteria to design networks of radars, based on two different paradigms (sparse network and dense network), are also presented. Finally, the space-borne radars for measuring clouds and precipitation from space, introduced through the Tropical Rainfall Measurement Mission (TRMM) program first and followed by the CloudSat and Global Precipitation Measurement (GPM) programs, are described.