Derived Observations From Frequently Sampled Microwave Measurements of Precipitation
Abstract: This is the first of two papers that quantify the high added value of frequent 3-D 3 radar observations of the atmosphere to capture the dynamics of weather systems. Recent advances in small small-satellite satellite and radar technologies, such as the “Radar in Cubesat� developed veloped at the Jet Propulsion Laboratory, are paving the way for the design of convoys of spaceborne radars that can directly observe the evolution of severe weather at very fine temporal scales. The analyses presented here are to establish the relation be between tween such observations to the underlying cloud variables and processes, and to quantify the sensitivity to the different physical and instrument parameters. In this first part, a robust algorithm is proposed to estimate the horizontal advection from succe successive ssive radar reflectivity measurements, and use it to compute total time derivatives dtZ of the observed radar reflectivity factors Z . As illustrated using Next-Generation Generation Radar measurements in a blizzard coupled with an atmospheric river in California, the th maps of dtZ reveal features about locations of sources and sinks of condensed water, which are, otherwise, not visible in the maps of Z alone. Using numerical simulations of the blizzard and a radiative radiative-transfer transfer model to forward calculate the corresponding ng reflectivity factors Z in the S-band, band, we show the robust correlation between dtZ and the moistening of the troposphere.