Impacts of QuikSCAT on Tropical Prediction Center

Operations

Impacts of QuikSCAT on Tropical Prediction Center

Operations

Richard Knabb, Christopher Hennon, Daniel Brown, James Franklin, Hugh Cobb,

Jamie Rhome, and Robert Molleda

NOAA/NWS/NCEP/TPC/National Hurricane Center, Miami, FL

Richard Knabb, Christopher Hennon, Daniel Brown, James Franklin, Hugh Cobb,

Jamie Rhome, and Robert Molleda

NOAA/NWS/NCEP/TPC/National Hurricane Center, Miami, FL

TPC/NHC Core Operational Products

Hurricane Specialists• Tropical Cyclone Public Advisory• Tropical Cyclone Forecast/Advisory• Tropical Cyclone Discussion• Tropical Cyclone Strike Probabilities• Special Disturbance Statements• Tropical Cyclone Updates• Tropical Cyclone Position Estimates• Tropical cyclone graphics

Tropical Analysis and Forecast Branch (TAFB)• High Seas Forecasts• Offshore Waters Forecasts• Tropical Weather Discussions• Marine Weather Discussions• Tropical surface analysis• Graphical marine products• Dvorak intensity estimates and satellite position fixes• Satellite rainfall forecast guidance• Pan-American temperature and precipitation table

TPC/NHC Core Operational Products

Hurricane Specialists• Tropical Cyclone Public Advisory• Tropical Cyclone Forecast/Advisory• Tropical Cyclone Discussion• Tropical Cyclone Strike Probabilities• Special Disturbance Statements• Tropical Cyclone Updates• Tropical Cyclone Position Estimates• Tropical cyclone graphics

Tropical Analysis and Forecast Branch (TAFB)• High Seas Forecasts• Offshore Waters Forecasts• Tropical Weather Discussions• Marine Weather Discussions• Tropical surface analysis• Graphical marine products• Dvorak intensity estimates and satellite position fixes• Satellite rainfall forecast guidance• Pan-American temperature and precipitation table

TPC/NHC AREAS OF RESPONSIBILITY

TPC HURRICANE FORECAST AREA

TPC BACKUP AREA FOR OCEAN PREDICTION CENTER (MOSTLY HIDDEN)TPC BACKUP AREA FOR WFO HONOLULU AND CPHC AREAS (PARTIALLY HIDDEN)

TPC TAFB FORECAST AREATPC TAFB ADDITIONAL SURFACE ANALYSIS AREA

TPC BACKUP AREA FOR AVIATION WEATHER CENTER (COMPLETELY HIDDEN)

TPC Numerical Weather Prediction Overview

4

Typical operational distributionof surface observations

Land, island and marine (ships, buoys)

Huge Gaps in Surface Data inTAFB Areas of ResponsibilityHuge Gaps in Surface Data inTAFB Areas of Responsibility

QuikSCAT Fills Some Data GapsQuikSCAT Fills Some Data Gaps

However, it has gaps of its own between swaths,which are fairly large in the Tropics

Ship data still important, esp. in swath gaps

Ship data still important, esp. in swath gaps

NAWIPS Display of QuikSCAT DataNAWIPS Display of QuikSCAT Data

Surface Analysis without QuikSCATSurface Analysis without QuikSCAT

Surface Analysis without QuikSCATSurface Analysis without QuikSCAT

Surface Analysis with QuikSCATSurface Analysis with QuikSCAT

Surface Analysis with QuikSCATSurface Analysis with QuikSCAT

High Seas ForecastHigh Seas Forecast

Surface Analysis with QuikSCATSurface Analysis with QuikSCAT

Gulf of Tehuantepec

Gulf of Papagayo

Rain flag often fails in these

events

Central America Gap WindsCentral America Gap Winds

Visit the TPC/TAFB Poster on Tehuantepec EventsVisit the TPC/TAFB Poster on Tehuantepec Events

Windward Passage

MonaPassage

Funneling of Winds in Atlantic PassagesFunneling of Winds in Atlantic Passages

Intertropical Convergence ZoneIncluding broad/double ITCZ structures

Intertropical Convergence ZoneIncluding broad/double ITCZ structures

18 March 200418 March 2004

Bad Data

Edge of Swath ProblemsVery common in the Caribbean

Edge of Swath ProblemsVery common in the Caribbean

Nov-Dec 2003 TAFB ForecasterSurvey Results

Nov-Dec 2003 TAFB ForecasterSurvey Results

• QuikSCAT data used during forecast shift at least 75% of the time

• When QuikSCAT led to changes in the wind velocities in analyses and forecasts, the revised winds were higher about 65% of the time

• Primary reasons for QuikSCAT data not being used on a particular forecast cycle are lack of timeliness and/or lack of data over the feature/area of interest

• QuikSCAT data used during forecast shift at least 75% of the time

• When QuikSCAT led to changes in the wind velocities in analyses and forecasts, the revised winds were higher about 65% of the time

• Primary reasons for QuikSCAT data not being used on a particular forecast cycle are lack of timeliness and/or lack of data over the feature/area of interest

34

21

42

32

40

28

48

22

48

32

46

27

0

20

40

60

80

1999 2000 2001 2002 2003 2004

Gales/Storms T.S./Hurcn

More than tropical

cyclones

Year

# Even t s

TAFB Warning EventsTAFB Warning Events

QuikSCAT Impacts on TAFB ProductsQuikSCAT Impacts on TAFB Products

• Important tool for locating weather features

• Important for determining the extent of certain wind speeds around a feature, which can affect warnings

• Data source for verifying forecasts and warnings

• Assist in determining reliability of ship data

• Comparison with model analyses and short-term forecasts

• Forecasters have gained a much better understanding of localized wind events (e.g., terrain gap flows)

• Increased confidence in forecasting these events

• Losing scatterometer data, without a viable replacement, would be severely detrimental to TAFB marine analyses, forecasts, and warnings

• Important tool for locating weather features

• Important for determining the extent of certain wind speeds around a feature, which can affect warnings

• Data source for verifying forecasts and warnings

• Assist in determining reliability of ship data

• Comparison with model analyses and short-term forecasts

• Forecasters have gained a much better understanding of localized wind events (e.g., terrain gap flows)

• Increased confidence in forecasting these events

• Losing scatterometer data, without a viable replacement, would be severely detrimental to TAFB marine analyses, forecasts, and warnings

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Hurricane Karl (2004)

Hurricane Karl (2004)Wind radii in N semicircle expanded from 120 to 175 nm

Hurricane Karl (2004)Wind radii in N semicircle expanded from 120 to 175 nm

However, uncertainty is

high since rain contamination a

significant problem in

tropical cyclones

However, uncertainty is

high since rain contamination a

significant problem in

tropical cyclones

Manual Directional Ambiguity AnalysisManual Directional Ambiguity Analysis

Formation of Tropical

Depression #2

3 Aug 2004

Formation of Tropical

Depression #2

3 Aug 2004

Northerly and northwesterly Northerly and northwesterly ambiguities suggest possible ambiguities suggest possible closed circulationclosed circulation

Visit the TPC/NHC Poster on Ambiguity AnalysisVisit the TPC/NHC Poster on Ambiguity Analysis

Normalized Radar Cross Section ImageryNormalized Radar Cross Section Imagery

Concentric Eyewalls of Hurricane

Isabel

11 Sep 2003

Concentric Eyewalls of Hurricane

Isabel

11 Sep 2003

QuikSCAT Impacts on NHC ProductsQuikSCAT Impacts on NHC Products

• Sometimes useful for estimating 34 kt wind radii

• Not as useful for 50 and 64 kt radii due to rain contamination

• Sometimes useful in estimating the intensity of tropical depressions and weak tropical storms, but not for hurricanes

• Automated solutions not very useful in TC center fixing

• Directional ambiguities sometimes analyzed to help determine if and where a surface circulation exists

• NRCS imagery occasionally useful in TC location fixing and in discerning concentric eyewalls

• Slight positive impact on NWP forecasts of TC track

• QuikSCAT explicitly mentioned during 2004 in 47 Tropical Cyclone Discussions (TCDs) for the Atlantic basin and in 43 TCDs for the eastern North Pacific basin

• Sometimes useful for estimating 34 kt wind radii

• Not as useful for 50 and 64 kt radii due to rain contamination

• Sometimes useful in estimating the intensity of tropical depressions and weak tropical storms, but not for hurricanes

• Automated solutions not very useful in TC center fixing

• Directional ambiguities sometimes analyzed to help determine if and where a surface circulation exists

• NRCS imagery occasionally useful in TC location fixing and in discerning concentric eyewalls

• Slight positive impact on NWP forecasts of TC track

• QuikSCAT explicitly mentioned during 2004 in 47 Tropical Cyclone Discussions (TCDs) for the Atlantic basin and in 43 TCDs for the eastern North Pacific basin

Looking AheadLooking Ahead• Continued operational availability of scatterometer data is greatly needed in TPC operations

• TPC forecasters have gained substantial experience with scatterometer data and have learned to extract much useful information… hopefully an investment in the future

• More than one instrument is needed due to large gaps between swaths in the Tropics and due to infrequent passes over a feature of interest

• Improvements needed to address challenges of rain contamination and directional ambiguities

• Ideally, if the passive radiometer is to be the future platform for retrieving ocean surface vector winds in operational tropical meteorology, it must be as accurate as the scatterometer

• Highly applied research with both platforms ongoing at TPC

• Continued operational availability of scatterometer data is greatly needed in TPC operations

• TPC forecasters have gained substantial experience with scatterometer data and have learned to extract much useful information… hopefully an investment in the future

• More than one instrument is needed due to large gaps between swaths in the Tropics and due to infrequent passes over a feature of interest

• Improvements needed to address challenges of rain contamination and directional ambiguities

• Ideally, if the passive radiometer is to be the future platform for retrieving ocean surface vector winds in operational tropical meteorology, it must be as accurate as the scatterometer

• Highly applied research with both platforms ongoing at TPC

Hurricane Specialists (NHC)• Develop, coordinate (domestically and abroad), and issue tropical cyclone warnings, forecasts, and outlooks• Provide "off-season” training to emergency managers, meteorologists, and the media• Conduct applied research and interact with research community• Conduct public awareness programs

Tropical Analysis and Forecast Branch (TAFB) • Develops, coordinates, and issues marine analyses, forecasts, and warnings• Provides satellite-based position and intensity estimates for tropical cyclones and other disturbances• Conducts public outreach to mariners• Augments operational support staffing to Specialists

Technical Support Branch (TSB) • Provides computer systems support 24x7, applications development, training, and technology infusion• Emergency operational support staffing to other branches

Hurricane Specialists (NHC)• Develop, coordinate (domestically and abroad), and issue tropical cyclone warnings, forecasts, and outlooks• Provide "off-season” training to emergency managers, meteorologists, and the media• Conduct applied research and interact with research community• Conduct public awareness programs

Tropical Analysis and Forecast Branch (TAFB) • Develops, coordinates, and issues marine analyses, forecasts, and warnings• Provides satellite-based position and intensity estimates for tropical cyclones and other disturbances• Conducts public outreach to mariners• Augments operational support staffing to Specialists

Technical Support Branch (TSB) • Provides computer systems support 24x7, applications development, training, and technology infusion• Emergency operational support staffing to other branches

TPC/NHC Branch ResponsibilitiesTPC/NHC Branch Responsibilities

77°N°N

3535°W°W

3131°N°N3030°N°N

18.518.5°S°S

140140°W°W

EQEQ

Surface Analysis in Hurricane SeasonSurface Analysis in Hurricane Season

Another Mona Passage ExampleAnother Mona Passage Example

Quikscat from 0050 UTC 25 January. Surface observations from 0400 UTCSSTs in Red

20 and 34 kt Wind Radii Estimation20 and 34 kt Wind Radii Estimation

QuikSCAT Impact onModel TC Track Forecasts

QuikSCAT Impact onModel TC Track Forecasts

Impact of Removing AMSU, HIRS, GOES Wind, Quikscat Surface Wind Data on Hurricane Track Forecasts in the Atlantic Basin - 2003 (34 cases)

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

12 24 36 48 72 96 120

Forecast Hour

% Im

pro

ve

me

nt

NOAMSU

NOHIRS

NOGOESW

NOQuikscat

Satellite data ~ 10-15% impact

Jung and Zapotocny

JCSDA work funded by NPOESS IPO

Jung and Zapotocny

JCSDA work funded by NPOESS IPO