Christopher Kidd - 613 Seminar Series

University of Maryland, Earth System Science Interdisciplinary Center & NASA/Goddard Space Flight Center
Water plays a critical role in many of the Earth systems, is vital to life on Earth and is essential to our own social and economic welfare. The key component in all of these is precipitation that provides freshwater, whether this is in the form of rainfall or snowfall. Measuring precipitation across the Earth is therefore of great importance. Conventional measurements utilizing surface gauges remain the de facto standard for precipitation measurement. However, gauges cannot provide all the necessary measurements across the Earth’s surface. Although weather radar systems provide the ability to measure the spatial distribution of precipitation, such measurements tend to restricted to regions with reasonable gauge density. For truly global measurements of precipitation it is necessary to utilize satellite observations; these comprise of observations taken in different parts of the electromagnetic spectrum, by a variety of sensors and processed by different techniques. Although the basic principles of estimating precipitation from these observations is relatively straightforward, relative complex techniques are required to enable accurate retrievals over the many different meteorological and climatological regimes. This presentation will present on-going work on retrievals schemes for current precipitation-capable missions, in particular, the Goddard Profiling (GPROF) scheme which is currently being adapted to exploit additional observations from the cross-track sensors. The presentation will also highlight the role of the users of precipitation products, ranging from the atmospheric scientist through to the hydrologist, essentially providing products with the necessary spatial and temporal scales commensurate with the different user requirements. Critically, there is an unfortunate but necessary trade-off between independent satellite measurements and other precipitation estimates, whether these are from models or from conventional surface measurements. ?