offshore observations - cepsym
TRANSCRIPT
IRENE Rainfall Forecast
an Extreme Event
Observed rainfall
Forecast rainfall
60 million peoplepotentially impacted
We need corollary to Land Falling Hurricanes in West for AR Landfall
Day 1
Day 3
25 Million at Risk
Day 2
Validation of AR Forecasts ‐ Approach
• AR features in model fields compared with satellite observations from SSMIS
• 5 models tested: NCEP, ECMWF, UKMO, JMA, & CMC
• Evaluated at lead times to 10 days• 3 cool seasons in NE Pacific from 2008‐9 to 2010‐11
• Compared frequency of occurrence, width, IWV content, and landfall location
Automated Atmospheric River Detection Tool (ARDT) applied to evaluate ability of operational NWP models to predict AR events
NCEP
Satellite ObservationsJanuary 7, 2009
UKMO
1‐Day Fcst 7‐Day Fcst
Evaluation of Atmospheric River Forecasts in Operational Ensemble Forecast Systems
G. A. Wick, P. J. Neiman, F. M. Ralph, & T. M. HamillNOAA ESRL/PSD, 2013
Validation of AR Forecasts – Results/Implications
While overall occurrence well forecast out to 10 days, landfall is less well predicted and the location is subject to significant errors, especially at longer leads
• Errors in location increase to over 800 km at 10‐day lead
• Errors in 12 hr forecasts of ARs comparable with current hurricane 3 ‐5 day track errors
• Model resolution a key factor
• Models provide useful heads‐up for AR impact and IWV content, but location highly uncertain
• Location uncertainty highlights limitations in ability to predict extreme precipitation and flooding
• Improvements in predictions clearly desirable
RMS Error in Forecast AR Landfall Location
From Wick et al., 2013
Conceptual Observation Network and Forecast Lead Time of an Extreme Event
Recurving West PacificTropicals 5‐7 days
Amplifying Jet Stream ‐ RWD
G‐IV
ProfilersMJO7‐10 days
Ensemble MJO Fcst
Frontal wave stalls AR over CA ‐ AROs
Tropical Tap?
UAVs
Landfall
Cost Comparisons
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Scanning NEXRAD Radar on WA coast$13 M (operating Sept 2011)
California AR Network>90 sites, 4 sensor types$10 M (underway)
Operate, Maintain and Optimize‐ $35 M/year
Offshore Buoy and Aircraft Network$40 M to develop, acquire and deploy ‐ 5 buoy‐mounted AROs‐ 1‐2 reconnaissance aircraft
Complete Western Network$65 M to develop, acquire and deploy ‐ 325 new surface obs‐ 25 Atmospheric river observatories‐ 25 precipitation profiling radars‐ 24 new C‐ or X‐band scanning radars
Combined: $210 M
over 6 years
Major satellitesystems can exceed $1 B
An Observing Network Design for Extreme Precipitation, Flooding and Climate
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The Western States Water Council passed a Resolution in July 2011 that “supports development of an improved observing system for Western extreme precipitation events, to aid in monitoring, prediction, and climate trend analysis associated with extreme weather events”
Over the last decade, NOAA’s Hydrometeorology Testbed (HMT) and other efforts have improved understanding of how extreme events occur, have identified gaps and prototyped solutions. The WSWC requested development of this Western Obs’ Vision, which was presented at a special workshop associated with their most recent meeting in Oct. 2011.
26 experts contributed, from more than 20 organizations.
Major strategies:‐ Land‐based atmospheric and snow‐pack monitoring‐ Coastal and offshore storm monitoring (especially ARs)‐ Better weather modeling, forecasts, and support for decision makers