Zorana Jelenak Paul S. Chang Khalil Ahmed (OPC) Seubson Soisuvarn Qi Zhu NOAA/NESDIS/STAR-UCAR

Transcription

1 Near Real Time ASCAT Wind Vectors at NOAA and High Wind Issue Zorana Jelenak Paul S. Chang Khalil Ahmed (OPC) Seubson Soisuvarn Qi Zhu NOAA/NESDIS/STAR-UCAR

2 ASCAT Wind Processing Implemented at NOAA Feb 2007 Input σ 0 values EUMETSAT Pre-processing σ 0 correction Inversion using CMOD5.5 GMF 25 and 12.5km products available in NRT Input NWP collocation (NOAA s GFS) Quality Control Ambiguity Removal KNMI Output Wind Vector Operational Users Research & Validation

3 % of Missing ASCAT L1B Files in NOAA Operations 16 NOAA incoming data server issues Anomaly on MetOp spacecraft MetOp payload switch off ASCAT L1B data missing files (%) [%] 8 6 MetOp out of plane maneuver May 07 Jul 07 Sep 07 Nov 07 Jan 08 Mar 08 May 08 Jul 08 Sep 08

4 % of On-time QuikSCAT Product Generation (End to End) Graphy L2 Data Latency % on time PRODUCT@115(min) % on time PRODUCT@120(min) % on time PRODUCT@125(min) [%] Nov 07 Dec 07 Jan 08 Feb 08 Mar 08 Apr 08 May 08 Jun 08 Jul 08 Aug 08 Sep 08 90% of ASCAT wind products produced and available to users within 125 minutes

5 ASCAT Winds in NOAA Operations North Atlantic and Pacific Dailyl Ocean Coverage ASCAT QuikSCAT ASCAT+QuikSCAT % Latitude Bands [deg] ASCAT provides a new, additional source of OSVW data in the large and mostly data void ocean regions within OPC and TPC s areas of responsibility (AOR) Extremely useful in rainy regions when QuikSCAT retrievals are questionable In low to moderate wind speed regimes two scatterometers have very comparable utility for marine forecasting and warning products High winds not many of them large difference between QuikSCAT and ASCAT

6 High Wind Issue

7 Utility of ASCAT in HF warnings Hurricane Force Observations Oct 2007-May QSCAT-Hi QSCAT-p ASCAT GFS ECMWF Surf. Obs. Khalil Ahmad NWS/OPC

8 12.5 KM QuikSCAT vs 25 (12.5) KM ASCAT Retrievals STORM GALE QuikSCAT Higher by ONE warning category in 8 out of 9 events Hugh Cobb NHC/TAFB

9 QuikSCAT-ASCAT-GDAS Wind Speeds

10 Turning Model Function Knob

11 Old vs New QuikSCAT NRT Wind Speeds 16m/s QSCAT-1MOD model function implemented in QuikSCAT NRT processing in May 2006

12 Hurricane Force Extratropical Cyclones - Detection and Warning Trend using QuikSCAT WARNING CATEGORIES Pre- QSCAT 1. GALE kt 2. STORM > C y c 40 l o n 30 e s 20 QSCAT ERA 1. GALE kt 2. STORM kt 3. HURCN FORCE > 64 kt QuikSCAT 10 Hurricane Force Warning Initiated Dec 2000 Detection increased with: -Forecaster familiarity -Data availability -Improved resolution -Improved algorithm Hurricane Force Wind Warning Initiated Dec 00 Launch Jun km QuikSCAT Available in N-AWIPS Oct km QuikSCAT available May Improved wind algorithm and rain flag Oct Atlantic Pacific

13 Storm and Gale Wind Events Gulf of Tehuantepec from New QuikSCAT processing implemented

14 Old vs New QuikSCAT NRT Wind Speeds QSCAT Maximum Wind Change with new NRT Algorithm in select 2003 Atlantic TCs 40 New-Old QSCAT Max Wind (k kt) Max. wind with new NRT processing 5 10 kt higher for old wind speeds > 55 kt Examined 64 passes Old QSCAT NRT Max Wind (kt) M. Brennan NHC

15 Average Old and New QuikSCAT Wind Bias Binned by NHC Best Track 2003 Sample Old vs New QSCAT Average TC Intensity Bias Bias slightly decreased in stronger hurricanes 0.0 TD TS H1-1.3 H2 H3 H Bias (kt) Smaller bias in marginal hurricanes due to cancellation of large positive and negative errors Old QS Bias New QS Bias NHC Best Track Classification M. Brennan NHC

16 High Wind Hurricane Aircraft Data and Scatterometer Model Functions

17 CMOD5 vs IWRAP C-Band V-Pol Model σ 0 = B 0 [1+B 1 cos(φ)+b 2 cos(2φ)] 1.6 Aircraft Model Function = Satellite Model Function

18 2008 Hurricane Season - NOAA P3 Flights 3 missions in hurricane Gustav, 1 mission in hurricane Hanna, 6 missions in hurricane Ike and 4 missions in TC Kyle flown during season, sampling wind speeds in the range of 5 to 70 m/s The dataset includes GPS dropsondes and collocated radiometer (SFMR) brightness temperatures measurements providing surface wind speed and precipitation estimates. 225km 9 ASCAT WVC 450 IWRAP WVC

19 Coordinated P3 ASCAT Underflight Hurricane Ike 09/06/08 2 WVC P3 position at the ASCAT overpass time 14:48UTC Max surface wind measured by sfmr 67.5 m/s Max dropsonde wind at 50m 73 m/s Max ASCAT wind m/s

20 Hurricane Ike 09/10/08 SFMR Wspd ~30m/s ASCAT Wspd ~ 17m/s P3 position at the ASCAT overpass time 2:39UTC

21 ASCAT vs IWRAP Model Function

22 ASCAT vs CMOD5 and IWRAP Model σ 0 = B 0 [1+B 1 cos(φ)+b 2 cos(2φ)] 1.6

23 σ meas 0 - σ mod 0 Differences Aircraft Model Function Satellite Model Function

24 What can be done and Should something be done and Can we reach an agreement on how to do it? What wind products do we want to produce? Peak winds? If QuikSCAT/ASCAT/WindSat/AMSR can really measure them do we need XOVWM? What changes in processing of measurements might lead to higher wind retrievals? Model function, data averaging, implemented retrieval scheme or measurement technique limitations? Calibrating high wind model function Calibration should be consistent with resolution of phenomena being measured Data sets used for model function development should be of comparable resolution with measurement resolution Wind products with comparable resolution should produce comparable winds

25 Extratropical Storms and Possible Hi Wind data sets

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27 Winter 2007 NOAA-P3 Field Campaign Seven missions flown sampling wind speeds in the range of 5 to 50 m/s (virtually rain-free conditions). The dataset includes GPS dropsondes and collocated radiometer (SFMR) brightness temperatures measurements providing surface wind speed and precipitation estimates.

28 0000 UTC 9 Feb 2007 Atlantic 12 km WRF PMSL Wind Speed 925 mb Theta, Theta gradient 925 mb frontogenesis