Results from Winter Storm Reconnaissance Program 2007

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Results from Winter Storm Reconnaissance Program 2007

Yucheng Song IMSG at EMC/NCEPZoltan Toth EMC/NCEP/NWS Sharan Majumdar Univ. of MiamiMark Shirley NCO/NCEP/NWS

http://www.emc.ncep.noaa.gov/gmb/targobs

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Acknowledgments

• NWS field offices, HPC/NCEP and SDMs• NOAA G-IV and the USAFR C-130 flight crews• CARCAH (John Pavone)• Jack Woollen - EMC• Russ Treadon - EMC• Mark Iredell - EMC• Istvan Szunyogh – Univ. of Maryland• Craig Bishop - NRL• + others who have contributed!

Winter Storm Reconnaissance Program

Objective:

Improve Forecasts of Significant Winter Weather Events Through Targeted Observations in Data Sparse Northeast Pacific Ocean

Adaptive approach to collection of observational data:1) Only Prior to Significant Winter Weather Events of Interest2) Only in Areas that Influence high impact event Forecasts

Results: 70+% of Targeted Numerical Weather Predictions Improve

10-20% error reduction for high impact event forecasts12-hour gain in predicting high impact events – earlier warnings possible

Operational since January 2001

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About the Winter Storm Reconnaissance (WSR 2007) Program

• Took place 20 Jan – 13 March 2007• Dropwinsonde observations taken over the NE

Pacific by aircraft operated by NOAA’s Aircraft Operations Center (G-IV) and the US Air Force Reserve (C-130s).

• Observations are adaptive – – collected only prior to significant winter weather events of

interest – in areas that might influence forecast the most.

• 31 flights, around 478 dropsondes this winter which is increased from 342 drops last year

• Several communication problems from C-130s

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About the Winter Storm Reconnaissance (WSR 2007) Program – (continued)

• Evaluation methods– NCEP Global Forecast System running on T126L28

resolution – Three sets of experiments

• A. GFS run with all the WSR dropsondes being assimilated

• B. GFS run without WSR dropsondes data rejected on all days

• C. GFS run with WSR dropsondes data rejected only on the WSR observation day (i.e. the guess files are the same as the operational while data file is different)

• Experiment Design - Experiment C is used for signal propagation studies, it can single

out the data impact due to current dropsondes clearly without worrying about the previous drops

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The ETKF spotted the target area

Expected error reduction propagation

Targeting methods - ETKF

Storm

Dropsondes to be made by G-IV

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Forecast verification(Jan 20-22,2007)

Red contours show forecast improvement due to WSR dropsondes, blue contours show forecast degradation

500mb height

250mb height

Sea Level Pressure

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Impact of Dropsondes

500mb height250mb height

Precipitation Surface pressure

Contours are 1000mb geopotential height, shades are differences in the fields between two experiments

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Comparison of ETKF signal and NCEP signal

The ETKF signal The NCEP signal

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Forecast Verification for Wind (2007)

RMS error reduction vs. forecast lead time

10-20% rms error reduction in winds

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Forecast Verification for Wind (2007)

RMS error reduction vs. forecast lead time

10-20% rms error reduction in Temperature

60 hr forecast is equivalent to 48hr forecast

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Breakdown for cases

Variable# cases

improved# cases neutral

#cases degraded

Surface pressure 25 0 12

Temperature 24 0 13

Vector Wind 27 0 10

Humidity 24 0 13

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Individual Case Comparison

1 denotes positive effect

0 denotes neutral effect

-1 denotes negative effect

26 OVERALL POSITIVE

0 OVERALL NEUTRAL

11 OVERALL NEGATIVE

70% improved 30 % degraded

VR OBSDATE P T V OVERALL REGION FHOUR AK 20070120 1 1 1 1 130W ,55N 48 C 20070128 1 -1 -1 -1 97W ,33N 72 W 20070207 1 -1 -1 -1 123W ,40N 48 W 20070208 -1 1 1 1 123W ,40N 24 W 20070209 1 1 1 1 122W ,38N 24 W 20070211 1 -1 1 1 110W ,32N 48 E 20070211 1 -1 -1 -1 86W ,36N 72 W 20070212 -1 -1 -1 -1 110W ,32N 36 E 20070212 1 1 1 1 77W ,38N 60 W 20070215 1 -1 1 1 120W ,45N 24 AK 20070216 1 -1 1 1 135W ,60N 48 W 20070217 1 1 1 1 124W ,40N 36 W 20070218 1 1 1 1 117W ,40N 24 C 20070218 1 1 1 1 108W ,37N 48 C 20070218 1 1 1 1 90W ,35N 72 W 20070220 1 1 1 1 122W ,40N 60 W 20070221 1 1 1 1 122W ,40N 36 C 20070221 1 -1 -1 -1 96W ,43N 72 C 20070221 1 1 1 1 93W ,40N 96 W 20070222 1 1 1 1 120W ,37N 24 C 20070222 -1 -1 -1 -1 90W ,40N 72 E 20070222 -1 1 1 1 80W ,36N 96 W 20070223 1 1 1 1 123W ,42N 48 C 20070223 1 -1 1 1 94W ,37N 48 W 20070225 -1 1 1 1 123W ,42N 48 W 20070226 1 1 1 1 123W ,42N 24 W 20070228 1 1 1 1 122W ,43N 36 E 20070228 -1 1 1 1 86W ,35N 48 W 20070302 1 1 1 1 125W ,49N 36 AK 20070306 -1 -1 -1 -1 130W ,55N 36 E 20070308 1 1 1 1 85W ,34N 108 W 20070308 -1 1 -1 -1 124W ,46N 60 W 20070309 1 -1 1 1 124W ,45N 72 C 20070310 -1 -1 1 -1 93W ,37N 48 C 20070311 -1 1 -1 -1 96W ,32N 36 E 20070311 -1 1 -1 -1 81W ,42N 96 E 20070313 -1 1 1 1 81W ,42N 48

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ETKF signal vs. NCEP signal (Feb 18-Feb 22)

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Contours are 1000mb geo-potential height, shades are differences in the fields between two experiments

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Contours are 1000mb geo-potential height, shades are differences in the fields between two experiments

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250mb height

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Overall results for Surface pressure

Of all cases:25 improved 0 neutral12 degraded

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Overall results for Temperature


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Overall results for Vector wind


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Overall results for Humidity


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WSR overall statistics (2004-2007)

Variable# cases

improved# cases neutral

#cases degraded

Surface pressure 21+20+13+25=79 0+1+0+0=1 14+9+14+12=49

Temperature 24+22+17+24=87 1+1+0+0=2 10+7+10+13=40

Vector Wind 23+19+21+27=90 1+0+0+0=1 11+11+6+10=38

Humidity 22+19+13+24=78 0+0+0+0=0 13+11+14+13=51

25+22+19+26 = 92 OVERALL POSITIVE CASES.

0+1+0 +0 = 1 OVERALL NEUTRAL CASES.

10+7+8 +11 = 36 OVERALL NEGATIVE CASES. 71.3% improved 27.9% degraded

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Issues with WSR07

• C-130s communication problems

• 6-hr data window requirement – Some of the dropsondes data were out of

the 6-hr window surrounding 00Z

Results from Winter Storm Reconnaissance Program 2007

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