# Presentation: 536277

## Impacts and Challenges of Integrating QuikSCAT into TPC Operations

- Christopher Hennon
- UCAR Visiting Scientist
- Tropical Prediction Center
- March 17, 2004

## National Ocean Partnership Program (NOPP) Project

- Goals
- Enhance operational utility of surface wind vector data (wvd) at TPC
- Quantify impacts of high resolution wvd at TPC
- Investigate new scatterometer products as they become available
- SeaWinds on Midori-II (dead)
- WindSat (passive polarimetric radiometry)
-  Collaborative effort between six agencies
- NESDIS, OPC, TPC, BYU, NRL, OCENS

## Outline

- SeaWinds on QuikSCAT
- Description / operation
- End product
- QuikSCAT Use at TPC
- Tropical Cyclones
- Tropical Marine Forecasts and Analyses
- Current QuikSCAT research at TPC
- Impact Study
- Tropical Cyclone center fixing
- Challenges and Future Work
- Concluding Remarks

## SeaWinds on QuikSCAT

- Active Ku Band (13.7 GHz) scatterometer
- Able to retrieve high resolution (25 or 12.5 km) 10-meter wind speed and direction
- Cross swath width of 1800 km
- 90% global coverage daily
- Accurate within 2 m/s for wind speeds of 2-20 m/s (~4 - 40 kt)
- Assuming no rain

## QuikSCAT Operation

**900km**

**53 deg**

**803** **km**

**46 deg**

## Slide 6

## Some QuikSCAT Applications at TPC

- Locations of weak tropical cyclones
- Outer wind field structure of mature tropical cyclones
- Locations of tropical waves
- Analyzing pressure fields
- Wind/wave forecasting
- Offshore waters forecast
- Verification of ship and buoy observations
- Verification with model analyses and SSM/I winds
- Diagnoses of high-wind events
- Gulf of Tehuantepec

## SSMI

**MSW = 25 kt. (TD) ****	**** MSLP = 1008 mb      11.2N  23.0W ( BT, 0000 Z 9/9)**

**SSMI**

## MSW = 140 kt.	MSLP = 932 mb	

**MSW = 140 kt.****	****MSLP = 932 mb**

**T.S. force**
**wind radii**

## 40+ kt wind 

**40+ kt wind **
**event confirmed**
**by QuikSCAT.  **
**Confident warnings**
**can be made**

## QuikSCAT Improves TPC Analysis and Forecasting

- Improvements in finding tropical waves, mesoscale wind events, and creating accurate pressure analyses over oceans
- Outer band wind structure in tropical cyclones
- Accurate fixes of weaker tropical cyclones (sometimes)
- Used in conjunction with other microwave imagery

## Current Research and Strategies

- Quantify impact of operational QuikSCAT data on tropical marine forecasting
- Goal: Identify uses,  strengths, and shortcomings of operational QuikSCAT wind retrievals

## Methodology

- Forecasters asked to complete log sheet after each forecast cycle
- One log sheet for each forecast desk
- 15-Nov – 15-Dec (2003)

## QuikSCAT Log Sheet – Pacific Desk

_**QuikSCAT Log Sheet – Pacific Desk**_
- Forecaster Name: _________________________________
- Date (mm/dd)  _______ / _______	For Synoptic Time __________ UTC

- 1) Did you use quikSCAT wind vectors for any of your products (circle one)?        YES    NO
- 2) If you answered ‘YES’ to #1, for which products did you apply quikSCAT information?
- 3) If you answered ‘NO’ to #1, why didn’t you use quikSCAT wind vectors in your products (please circle)?
- 	a. No data available
- 	b. Data available but not timely
- 	c. No relevant information from quikSCAT data
- 	d. Rain contamination / edge of swath problems
- 	e. Other (please comment)
-                                   _____________________________________________
- 		_____________________________________________
- 4) If you answered ‘YES’ to #1, how did the quikSCAT data change your analysis/forecast from
-     what it would have been without the data (circle all that apply)?
- 	a. Forecasted/Analyzed higher wind speeds for the region of _________ N _________ W
- 	b. Forecasted/Analyzed lower wind speeds for the region of _________ N _________ W
- 	c. Changed the pressure and/or wave forecast(s) for (circle) front / tropical wave / ridge
- 	d. Resulted in the issuance or upgrade of a wind warning for _______ N _______ W
-       	e. Resulted in a downgrade of a wind warning for _________ N _________ W
- 	f. QuikSCAT data did not change my analysis/forecast
- 	g. Other (please specify in box below)

## Results

- Main Findings:
- QuikSCAT data used during the forecast cycle about 75% of the time
- When QuikSCAT data changed the wind analysis/forecast, the new winds were usually higher in velocity (65%, lower 35%)
- The main reason QuikSCAT was not used during the forecast cycle was lack of timeliness (37%) or no data available (32%)

## Selected Forecaster Comments

| “Confirmed placement of ATL low/stationary front with 10Z pass” |
| --- |

- “Used to place features like fronts & troughs, tighten isobars near hi wind speeds”

- “Verify position of 1010 mb low in EPAC near 11N 126W”

- “Only small area of EPAC available - not much help”

- [rain contamination] “Prevented finding location of Low in SW Caribbean - vectors implied
- no circulation.  Had to consult sat imagery and surface obs.”

- “ Adj wnds to 40kt in Gulf of Tehuantepec gale area based on 00Z qsct pass of 40 kt.”

- “Confirmed AVN fcst for 06Z and SSMI imagery.  Qsct in good agreement”

- “Higher  winds 15N, 120W & Papagayo, lower wnds 20N, 108W.  Missing data hurt!”

- “Windward Passage - confirmed ship obs of 25-30 kt.”

- “Would be nice to have current qsct passes for 00Z run”

## Current Research and Strategies

- QuikSCAT tropical cyclone fix study
- Goals
- Determine under what conditions (strength of surface wind, presence/strength of rain, etc.) an accurate center fix from QuikSCAT can be realized.
- Explore analyses of directional ambiguities as a method of improving center fixing capabilities

## Challenges

- Tropical cyclones contain large areas of heavy rain
- Wind vector retrievals frequently ineffective, both in speed and direction
- In high wind variance events (Gulf of Tehuantepec), rain flagging algorithm fails
- Forecasters need to trained on what to use and when
- Timely coverage sometimes not available
- Scanning geometry results in bad retrievals near edge of swath and near nadir

## MSW = 20 kt. (TD) 	MSLP = 1009 mb      	13.8N  28.7W ( BT, 0600 Z)	

**MSW = 20 kt. (TD) ****	****MSLP = 1009 mb      ****	****13.8N  28.7W ( BT, 0600 Z)****	**

## Future Work

- Explore better techniques for using QuikSCAT wind velocities in convective areas
- Evaluate higher resolution data (12.5 km), available soon to forecasters
- Ambiguity analyses
- Explore accuracy of QuikSCAT vs. new surface wind products (WindSat)

## Concluding Remarks

- Loss of Midori-II satellite eliminates enhanced scatterometer coverage for at least the next two years
- QuikSCAT will continue to provide valuable near surface wind data for all coastal areas through at least 2006
- Very accurate in most instances!!