climatology of hurricane force extratropical cyclones

Center for Satellite Applications and Research (STAR) Review 09 – 11 March 2010

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

Climatology of Hurricane Force Extratropical Cyclones

Presented by

Paul Chang

Presented by

Paul Chang

2 Center for Satellite Applications and Research (STAR) Review

09 – 11 March 2010 Center for Satellite Applications and Research (STAR) Review

09 – 11 March 2010

Requirement, Science, and BenefitRequirement, 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



09 – 11 March 2010

Challenges and Path ForwardChallenges 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



09 – 11 March 2010

Project TeamProject 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



09 – 11 March 2010

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

xx

x

x

x

HURCN FORCESTORMGALELOW

Cyclone Centers – 1800 UTC 13 Dec 200611 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 ofExtratropical Cyclones?

Why Study Climatology ofExtratropical Cyclones?



09 – 11 March 2010

Defining Climatological Trend of ETCsis Critical for Climate Studies.

Defining Climatological Trend of ETCsis Critical for Climate Studies.

QuikSCAT Launch Jun 99

Hurricane Force Wind WarningInitiated Dec 00

25 km QuikSCATAvailable in N-AWIPS

Oct 01

12.5 km QuikSCATavailable May 04

Improved wind algorithm and rain flag Oct 06

TotalsAtlantic-289Pacific-269

558

Is trend increasing, decreasing or is it just cyclical?

QuikSCAT wind measurements constantly revealed existence of Hurricane Force winds within ETCs.



09 – 11 March 2010

Peak Season and Longevity of Hurricane Force ETCs – 9 years of Data

Peak Season and Longevity of Hurricane Force ETCs – 9 years of Data

8yr Average Monthly Distribution

0

2

4

6

8

10

Sept Oct Nov Dec Jan Feb Mar Apr May

Month

Aver

age n

umbe

r of

HF cy

clone

s (8y

rs)

Longevity Distribution

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 More

#6 hr increments at HF Intensity

8yr

Freq

uenc

y D

istr

ibut

ion

Peak Season for Hurricane Force ETC is from December to February

Peak Season for Hurricane Force ETC is from December to February

Hurricane Force conditions are short lived. They usually last between 6-24h.

Hurricane Force conditions are short lived. They usually last between 6-24h.



09 – 11 March 2010

Gale Force Wind Frequency

Storm Force Wind Frequency

ECMWFHurricane 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

QuikSCATHurricane Force Wind Frequency

QuikSCAT versus ECMWF ModelQuikSCAT versus ECMWF Model



09 – 11 March 2010

ETCs observed by QuikSCATETCs observed by QuikSCAT

QuikSCAT ECMWF analysis

Average size of ETCs observed by QuikSCAT measurements is ~3000km. Climate models predict only 2/3 of this observed size.



09 – 11 March 2010

Challenges and Path ForwardChallenges 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

climatology of hurricane force extratropical cyclones

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