Observational characteristics of atmospheric rivers from dropsondes Workshop: Warm Conveyor Belts – a challenge to forecasting Wednesday 11 March, 17:05 (10:05 Pacific time) Alison Cobb, Allison Michaelis, Sam Iacobellis, F. Martin Ralph & Observational Team
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Observational characteristics of atmospheric rivers from dropsondes
Workshop: Warm Conveyor Belts – a challenge to forecastingWednesday 11 March, 17:05 (10:05 Pacific time)
Alison Cobb, Allison Michaelis, Sam Iacobellis, F. Martin Ralph& Observational Team
Motivation
➢ A better understanding of AR processes: Observations
(Ralph et al., 2017)
• The total instantaneous water vapor flux in an average AR ~ 27 Mississippi Rivers (Ralph et al., 2017)
• Heaviest rains: 92% of West Coast’s heaviest 3-day rain events fed by ARs (Ralph & Dettinger, 2012)
• Cycles of wet and dry: 85% of multiyear precipitation variance in California (Dettinger & Cayan, 2014)
• AR scale: intensity and duration (Ralph et al., 2019)
• Flood damages increase exponentially with AR category (Corringham et al., 2019)
(Corringham et al., 2019)
CalWater Field Studies Designed to Quantify the Roles of Atmospheric Rivers and Aerosols in Modulating U.S. West Coast Precipitation in a Changing Climate
SponsorsDOE, NOAA
California Energy CommissionCalifornia Dept. of Water Resources
NSF, NASA, ONR
LocationsCalifornia
Eastern Pacific Ocean
Field seasonsCalWater-1: 2009-2011CalWater-2: 2014-2016
AR Recon Atmospheric River reconnaissanceSupport water management decisions and flood forecasting by developing and testing the potential of targeted airborne and buoy observations over the Northeast Pacific to improve forecasts of the landfall and impacts of atmospheric rivers on the U.S. West Coast at lead times of 1-5 days.
PI: F. Martin Ralph (UC San Diego/Scripps Institution of Oceanography/CW3E)
1. Separate into transects2. Calculate IVT from dropsonde data3. Identify dropsonde with max IVT in transect4. Calculate percentage of max IVT in each transect5. Allocate to sector:
Brown = drops not in a transectGrey = Cold / warm not deciphered by code – will manually addSector identification