Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

PDF

Portland State University

Geography Faculty Publications and Presentations

Series

Ageostrophy

Articles 1 - 1 of 1

Full-Text Articles in Physical Sciences and Mathematics

Dropsonde Observations Of The Ageostrophy Within The Pre-Cold-Frontal Low-Level Jet Associated With Atmospheric Rivers, Rueben Demirdgian, Joel R. Norris, Andrew Martin, F. Martin Ralph Jan 2020

Dropsonde Observations Of The Ageostrophy Within The Pre-Cold-Frontal Low-Level Jet Associated With Atmospheric Rivers, Rueben Demirdgian, Joel R. Norris, Andrew Martin, F. Martin Ralph

Geography Faculty Publications and Presentations

The pre-cold-frontal low-level jet (LLJ) is an important contributor for water vapor transport within atmospheric rivers, though its dynamics are not completely understood. The present study investigates the LLJ using dropsonde observations from 24 cross-atmospheric river transects taken during the CalWater-2014, 2015 and the AR-Recon 2016, 2018 field campaigns. It is found that the LLJ, located at ;1-km elevation ahead of the cold front, has an average maximum wind speed of 30ms21 and is strongly supergeostrophic with an average ageostrophic component of 6ms21. The alongfront ageostrophy occurs within the atmospheric layer (750–1250 m) known to strongly control orographic precipitation associated …