Study of Extratropical Cyclone Wind Fields by Combining Model and QuikSCAT Satellite Data

1. October Storm track file QuikSCAT ECMWF 6-12h Study of Extratropical Cyclone Wind Fields by Combining Model and QuikSCAT Satellite Data 0-6h November October December January 12-18h 0-6h Hurricane Force Wind Frequency Hurricane Force Wind Frequency N Read HF Cyclone Info. Extract Science QS 12.5km Data & Perform QC (land, ice, coast, rain) flags Generate Mean Wind Fields W E • Hurricane Force Warning Initiated Dec 2000 • Detection increased with: • Forecaster familiarity • Data availability • Improved resolution • Improved algorithm Improved wind algorithm and rain flag Oct 06 Storm Force Wind Frequency Storm Force Wind Frequency WARNING CATEGORIES Pre- QSCAT 1. GALE 34-47 kt 2. STORM >48 QSCAT ERA 1. GALE 34-47 kt 2. STORM 48 -63 kt 3. HURCN FORCE > 64 kt November February 6-12h 18-24h S 12.5 km QuikSCAT available May 04 >24h January 12-18h February March 18-24h 25 km QuikSCAT Available in N-AWIPS Oct 01 5000km 5000km Hurricane Force Wind Warning Initiated Dec 00 >24h Estimate speed & Angle (Heading Vector) Totals A-289 P-269 558 Gale Force Wind Frequency Gale Force Wind Frequency December March QuikSCAT Launch Jun 99 5000km 5000km Storm ID Date Lat Lon Pres. Type North Mean motion Storm motion Generate Frequency of HF Occurrence per grid fields East QuikSCAT ECMWF 11 different cyclones were occurring in the Pacific ocean at the same time QuikSCAT identified HF (>64kts) winds on Dec 13th, this storm struck Seattle on Dec 15th Dec 2006 Pacific NW Storm • Maritime extratropical cyclones exist year round. • Sep through May these storms can generate hurricane force winds, waves up to 100ft, and are a significant threat to ocean and coastal commerce. • When they impact land they produce: • strong winds • high surf • significant coastal flooding • snow, rain, and blizzard conditions • power outages HURCN FORCE STORM GALE LOW Khalil A. Ahmad, Zorana Jelenak, Paul Chang, and Joseph Sienkiewicz • Requirement: • Climate: • - Describe and understand the state of the climate system through integrated observations, • monitoring, and data management • - Understand and predict climate variability and change from weeks to decades to a century • - Improve the ability of society to plan for and respond to climate variability and change • Science: • Decadal trends of hurricane force extratropical cyclones (ETC) and the • resulting impact on Oceanic and Atmospheric forcing • Address the gap in knowledge of the most explosive ETCs as compared to tropical • cyclones; • Our estimate based on hurricane climatology indicates that tropical cyclones alone • would contribution to ~ 2 – 4 Wm-2 • Contribution from winter storms? • Investigate trends and impacts of cyclonic wind stress, curl, divergence and sea surface • temperatures (SST’s) associated with HF ETCs on ocean forcing; • Study the difference in trends and characteristics of HF ETCs resulting from QuikSCAT and • ASCAT scatterometer observations of these extreme conditions in order to develop analysis • techniques that will help improve the use of different scatterometer data in an operational • environment. • Benefit: • National Weather Service forecasters • Marine commerce ETC HF cyclone Database Monthly Wind Speed Distribution & Frequency from QuikSCAT 2001-2008 North Pacific • Estimate cyclone motion speed and direction • Extract all hurricane force 6-h cycles per month • Extract hurricane force events during 6h, 12h 18h, 24h and >24h • Perform statistical analysis of these events • Select QuikSCAT files that correspond to each chosen event Mean Wind Speed Distribution & Frequency from QuikSCAT (HF ETC Development Stage) 2001-2008 North Pacific Mean Wind Speed Field & Frequency 2007-2008 North Pacific Extratropical Cyclone (ETC) ETCSocietal Impact Number of detected Hurricane Force (HF) ETC • Science Challenges: • Address the gap in knowledge of the most explosive ETCs as compared to tropical cyclones; • Our estimate based on hurricane climatology indicates that tropical cyclones alone would • contribution to ~ 2 – 4 Wm-2 • - Contribution from winter storms? • Investigate trends and impacts of cyclonic wind stress, curl, divergence and • sea surface temperatures (SST’s) associated with HF ETCs on ocean forcing • Next Steps: • Utilize the multiyear time series of QuikSCAT, SeaWinds and ASCAT wind • vector products • Analyze the complementary information from multiple wind sensors • Develop analysis techniques that will improve the impact and effectiveness of • scatterometer data for operational uses • Transition Path: • Knowledge and data analysis techniques developed will be transitioned by Ocean • Prediction Center (OPC) HF ETC Climatology