GCPEx

GPM flying over Earth with a data swath visualized.
To augment the observations and provide additional test cases for synthetic algorithm development and satellite simulator testing, a number of modeling activities are also planned. Cloud resolving model simulate frozen precipitation events using the GSFC-Weather Research and Forecasting (WRF) will be performed, initialized and forced by appropriate NWP forecast models. The GSFC WRF has single-moment Goddard Microphysics and spectral-bin microphysics. All of the microphysical schemes have their own set of unique capabilities and assumptions, and all will be tested by the GPM groups. In turn...
GPM flying over Earth with a data swath visualized.
Frozen precipitation is particularly difficult to measure from space due to the wide variability in snowflake shapes and behavior. Snowflakes can have different impacts on the active and passive instruments signals compared to liquid precipitation, which is further complicated by a weak signal to noise ratio resulting from different scattering properties of liquid verses frozen precipitation. In recent years, the capability to quantify liquid precipitation from space has been greatly enhanced with the addition of several measurement capabilities from low-Earth orbit, most notably from passive...
GPM flying over Earth with a data swath visualized.
Falling snow is critically important for society in terms of freshwater resources, atmospheric water and energy cycles, and ecosystems. However, there are few archives of falling snow around the world that can be used to improve measurements from satellites. GCPEx will make detailed in situ observations of cloud and frozen precipitation microphysics to improve these databases. Falling snow represents a primary contribution to regional atmospheric and terrestrial water budgets, particularly at high latitudes. While often overlooked, precipitation falling in the form of snow is critically...
Document Description

During the GPM pre-launch period physically-based snowfall retrieval algorithms are in an active phase of development. Further refinement and testing of these emerging algorithms requires the collection of targeted ground-validation datasets in snowing environments. This document describes a field campaign effort designed to provide both new datasets and physical insights related to the snowfall process- especially as they relate to the incorporation of appropriate physics into GPM snowfall retrieval algorithms.