Center for Satellite Applications and Research (STAR) Review 09 – 11 March 2010 Image: MODIS Land Group, NASA GSFC March 2000 Climatology of Hurricane Force Extratropical Cyclones Presented by Paul Chang Presented by Paul Chang

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Requirement, Science, and Benefit 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 What are the decadal trends of hurricane force extratropical cyclones (ETC) and what is the resulting impact on Oceanic and Atmospheric forcing? Benefit Better understanding of climate variability and trends of extreme ocean events, and thus the ability of society to plan and respond to climate variability and change is improved

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Challenges and Path Forward Science challenges –Address the gap in knowledge of the most explosive ETCs as compared to tropical cyclones; –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 and –Develop analysis techniques that will improve the impact and effectiveness of scatterometer data for operational uses Transition Path –Analysis techniques developed and new knowledge gained will be transitioned into NWS operations and NOAA’s climate program

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Project Team Zorana Jelenak - Project Lead, Project Scientist UCAR Khalil Ahmad - Scientist, Perot Systems Joseph Sienkiewicz – NWS, Ocean Prediction Center Paul Chang – Ocean Winds Team Lead, STAR Qi Zhu - Scientific Programmer, Perot Systems Micah Baker - Unix System Administrator, Perot Systems

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Maritime extratropical cyclones generate hurricane force winds, waves up to 100ft, and are a significant threat to ocean and coastal commerce. On land they produce strong winds, high surf, flooding, snow, rain and power outages. Climatology of these most extreme storms is not well understood. x x x x x x x x HURCN FORCE STORM GALE LOW Cyclone Centers – 1800 UTC 13 Dec 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 QuikSCAT Wind Speed kt Why Study Climatology of Extratropical Cyclones?

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Defining Climatological Trend of ETCs is Critical for Climate Studies. QuikSCAT Launch Jun 99 Hurricane Force Wind Warning Initiated Dec km QuikSCAT Available in N-AWIPS Oct km QuikSCAT available May 04 Improved wind algorithm and rain flag Oct 06 Totals Atlantic-289 Pacific Is trend increasing, decreasing or is it just cyclical? QuikSCAT wind measurements constantly revealed existence of Hurricane Force winds within ETCs.

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Peak Season and Longevity of Hurricane Force ETCs – 9 years of Data Peak Season for Hurricane Force ETC is from December to February Hurricane Force conditions are short lived. They usually last between 6-24h.

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Gale Force Wind Frequency Storm Force Wind Frequency ECMWF Hurricane Force Wind Frequency Numerical models are not capable of predicting hurricane force winds within ETCs; therefore, they can not be used for accurate climate study of trends and characteristics of these storms. Gale Force Wind Frequency Storm Force Wind Frequency QuikSCAT Hurricane Force Wind Frequency QuikSCAT versus ECMWF Model

Center for Satellite Applications and Research (STAR) Review 09 – 11 March ETCs observed by QuikSCAT QuikSCATECMWF analysis Average size of ETCs observed by QuikSCAT measurements is ~3000km. Climate models predict only 2/3 of this observed size.

Center for Satellite Applications and Research (STAR) Review 09 – 11 March Challenges and Path Forward Science challenges –Address the gap in knowledge of the most explosive ETCs as compared to tropical cyclones; –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 and –Develop analysis techniques that will improve the impact and effectiveness of scatterometer data for operational uses Transition Path –Analysis techniques developed and new knowledge gained will be transitioned into NWS operations and NOAA’s climate program