An X-band radar network for cloud research: sampling strategies and research applications

Coincident observations of clouds and precipitation over a large domain (50x50 km) require a distributed, heterogeneous radar network to overcome sensitivity and resolution requirements for cloud research. The ARM radar facility at Southern Great Plains (SGP) in Oklahoma is a unique radar facility in the world designed to provide such an integrated radar view of cloud and precipitation. The facility includes a dual-polarization C-band, a dense network of three X-band radars, dual frequency Ka/W-band, zenith pointing Ka-band radar and a small network of radar wind profilers. The network of X-band weather radars has been proposed to bridge the gap between the profiling/scanning cloud radars and the surveillance C-band observations. X-band radars have been primarily used for precipitation studies. However, in a dense network (~20 km spacing) formation, X-band radars can be used to extract cloud and “first precipitation echo” measurements over a considerable domain suitable for studying the shallow-to-deep precipitation transition and cloud layer microphysics and dynamics. This paper presents the novel, adaptive, scanning strategies deployed by the X-band network to enable cloud research. Observations from the ARM X-band radar network during the Midlatitude Continental Convective Clouds Experiment (MC3E) are presented. Several research application are discussed including: i) low-level divergence measurements using insect returns, ii) shallow cumulus clouds detection and dynamics, iii) mid- and high-level cloud observations and iv) large-scale precipitation microphysics.