CAREER: The Upstream Impacts of Mountains on Frontal Precipitation Using Olympic Mountain Experiment (OLYMPEX) Observations

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This award supports research to study the development of precipitation over mountainous terrain. Increased rainfall and snowfall often occur when weather systems are forced to go over or around mountainous terrain, significantly impacting the availability of water for regions such as the Olympic Mountains of Washington State, but also increasing the risk of hazards such as flooding, avalanches and mudslides. Under some conditions, the location and intensity of this intensified precipitation can change, with this terrain-induced enhancement occurring at distances upstream of the mountains themselves. Quantifying how, and where, this upstream precipitation enhancement occurs and how it evolves in rapidly changing conditions is crucial to completing the full picture of how these weather systems provide precipitation to a region, as well as more accurately quantifying the evolving weather-related hazards that come with the system interacting with terrain. Through comprehensive field observations and high-resolution numerical simulations, this project will quantify the conditions where this upstream enhancement occurs and identify the mechanisms that lead to this enhancement in rapidly evolving atmospheric flows. This project will coincide with the development of a holistic mentoring and research experience program to support the transfer of students from two-year college programs. Through a comprehensive mentorship model, this program will develop cross institutional relationships while also providing year-round research, communication skill building, and professional development opportunities to support students’ path into geosciences. This project use analysis of high-resolution radar data and soundings collected during NASA-NSF OLYMPEX field campaign, operational data from the National Weather Service WSR-88D radars and NWS Quillayute, WA sounding station, and complimentary high-resolution numerical simulations to quantify how frontal precipitation processes are uniquely altered upwind of the Olympic Mountains of Washington State. The main tasks will be to identify the preferred regions of orographic precipitation enhancement upstream of the mountains through statistical analysis of operational radar data, to quantify the variability and evolution of upstream flow diversion through high-resolution Doppler analysis and numerical simulations, and to determine how variations in low-level winds and atmospheric stability extend the reach of the orographic enhancement and how this affects frontal circulations and precipitation through detailed case study analysis of ground-based and satellite-based radars. This research will contribute new understanding about the interaction of fronts and other highly variable atmospheric flows with isolated mountain ranges, which has significant implications for understanding the distribution and evolution of orographically-enhanced precipitation around mountainous islands. 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.