Collaborative Research: The Relationship of the Spatial/Temporal Variability of Rain to Scaling

Rjh Scientific Incorporated, El Cajon CA

Investigators

Abstract

Scientists have been studying the non-homogeneity of rainfall for decades. Simply put, raindrops collide, break apart, cluster, and spread out on their way to the ground. This introduces a variety of fall speeds, drop sizes, and instantaneous rainfall intensities that have significant impacts on a wide range of topics from flood forecasting to erosion to communications system availability. This research project will take advantage of a newly developed network of rain sensors to conduct a multitude of studies on rainfall characteristics. The main societal impacts fall under the umbrella of public safety and productivity. Rainfall characteristics are important for weather radars and weather forecast models for flood prediction, and for the prediction of communications drop-outs along land links and satellites. Undergraduate students will participate in the research, allowing for development of the next generation of scientists. The research team will continue their studies into the spatial and temporal variability of rainfall with an enhanced focus on scaling. The team will perform structural and statistical exploration of rain by collecting and analyzing time series rain observations over a newly configured network that consists of two 2D video disdrometers (2DVD), six 1D optical disdrometers (1DVD), and 21 Laser Precipitation Monitors (LPM). The objectives to be addressed during the work period include: exploring the frequency of the statistical heterogeneity of rain in a wider variety of meteorological conditions, comparing 2DVD observations to those interpolated over a small network of LPMs, characterizing the 1DVD estimates with those of different neighboring instruments, using 2DVD data to detect structures having scales relevant to radar Bragg scatter from precipitation, expanding our understanding of the scaling of DSD and their integrated parameters in statistically homogeneous conditions and in a variety of different meteorological conditions, beginning preliminary observations of the effect of measurements at different heights above ground, and combining 2DVD observations from two instruments for unique simultaneity studies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.