Impact of US Polar Orbital Satellite Data Loss on Nation’s High Impact Weather Forecast Capability: Summary of Recent Data Denial Experiments Environmental

Impact of US Polar Orbital Satellite Data Loss on Nation’s High Impact Weather Forecast

Capability:

Summary of Recent Data Denial Experiments

Environmental Modeling Center National Centers for Environmental Prediction

Camp Springs, Maryland, USA

Overview• Performance Metrics• Satellite Data Impact on Forecast Error• Global NWP Impact of Actual Satellite Data Loss • Global NWP Impact of Satellite Denial Experiments

– Data Denial Experiment Background– Data Denial Experiment Design– Case 1: “Snowmageddon” Storm – Feb 5-6, 2010– Case 2: NYC and New England Blizzard – Dec 26-27, 2010– Case 3: Northern Pacific Alaskan Coastal Storm– Case 4: Tornado Outbreak– Case 5: Tornado Outbreak

• Summary

Performance Metrics• Satellite data is required to help meet key

performance metrics :– Numerical Weather Prediction

• Global Anomaly Correlation Score – “Internal” metric• Related to ability to meet service-based metrics (below)

– National Weather Service GPRA* Metrics (* Government Performance & Results Act)• Hurricane Track and Intensity Forecast Accuracy• Winter Storm Warning Lead Time and Accuracy• Precipitation Threat Accuracy• Flood Warning Lead Time and Accuracy• Marine Windspeed and Wave Height Forecast Accuracy

Satellite Data Impact on Forecast Error

• Statistical estimation of relative improvement made to operational NWP system by various observing systems

• Based on adjoint model sensitivity technique

Operational ECMWF system September to December 2008. Averaged over all model layers and entire global atmosphere. % contribution of different observations to reduction in forecast error.

Courtesy: Carla Cardinaliand Sean Healy, ECMWF

Forecast error contribution (%)

O3: Ozone from satellites METEOSAT IR Rad (T,H)

MTSATIMG: Japanese geostationary sat vis and IR imagery GOES IR rad (T,H)

MODIS: Moderate Resolution Imaging Spectroradiometer (winds) GMS: Japanese geostationary satellite winds

SSMI: Special Sensor MW Imager (H and sfc winds) AMSRE: MW imager radiances (clouds and precip)

MHS: MW humidity sounder on NOAA POES and METOP (H) MSG: METEOSAT 2nd Generation IR rad (T,H)

HIRS: High-Resol IR Sounder on NOAA POES (T,H) PILOT: Pilot balloons and wind profilers (winds)

Ocean buoys (Sfc P, H and winds) METEOSAT winds

GOES winds AMSU-B: Adv MW Sounder B on NOAA POES

SYNOP: Sfc P over land and oceans,H, and winds over oceans QuikSCAT: sfc winds over oceans

TEMP: Radiosonde T, H, and winds GPSRO: RO bending angles from COSMIC, METOP

AIREP: Aircraft T, H, and winds AIRS: Atmos IR Sounder on Aqua (T,H)

IASI: IR Atmos Interferometer on METOP (T,H) AMSU-A: Adv MW Sounder A on Aqua and NOAA POES (T)

0 2 4 6 8 10 12 14 16 18Note:1) Sounders on Polar Satellites reduce forecast error most2) Results are relevant for other NWP Centers, including NWS/NCEP

Global NWP Impact of Actual Satellite Data Loss

• January 1, 2009 telecommunications outage• Substantial fractions of polar satellite sensor

data not available for model assimilation– Illustrated on following slide

• Numerical Weather Prediction centers of all nations suffered degraded skill in their global forecasting systems as result of lost data– See slide after next

18% loss 36% loss

33% loss

100% loss 100% loss

32% loss

AMSUA

HIRS4

GPSRO

AIRS

MHS

QSCAT

New Year’s Day 2009 Satellite Data Loss

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Global Model Skill Scores After 5-6 Days

Southern Hemisphere (SH) Dropouts (score below 0.7) for the GFS, UKMET, CAN, and FNMOC models; European Center skill degraded

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Global NWP Impact of Satellite Data Denial Experiments

Data Denial Experiment Background

• Data denial experiments designed to assess impact of having no afternoon polar orbiter data on the accuracy of Global NWP– Intended to contribute to discussions concerning

the impact of a potential gap in p.m. polar orbit coverage expected to result from JPSS launch delay

• Data denial case studies selected to include significant weather events that affected lives, property, and commerce for US citizens

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Data Denial Experiment Design

Control: NCEP operational 27 Km Global Forecast Model (GFS)

Experiment: Model T574L64.

All U.S. Polar Orbiting Satellite data from afternoon orbits was removed from the experimental runs

Satellite data removed: AMSUA_NOAA15, AMSUB_NOAA15, HIRS3_NOAA17, AMSUA_NOAA18, MHS_NOAA18, AIRS_AQUA, AMSUA_AQUA,HIRS4_NOAA19, & AMSUA_NOAA19

Satellite data kept: HIRS4_METOP-A, AMSUA_METOP-A, MHS_METOP-A, IASI_METOP-A, & ALL GOES SOUNDERS.

Case 1: “Snowmageddon” Storm – Feb 5-6, 2010

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24 Hr Accumulated Snowfall Totals (inches) for 6 Feb (am)

Case Study 1: “Snowmageddon”February 6, 2010

Forecast comparison using NOAA’s Polar-orbiting Operational Environmental Satellite Data

Observed Snowfall5 day forecast with all NOAA

orbiting satellite data5 day forecast without NOAA

afternoon orbiting satellite data

Result: In DC and Mid-Atlantic coast, models without NOAA orbiting satellite data did not forecast this paralyzing event and under-forecast snow by at least 10 inches Impacts: Aircraft and airline passengers would have been stranded, ground commerce would have been halted with no mitigation plans, population would have been unprepared for paralyzing snow-depth

0.1 1 2.5 5 7.5 10 12.5 15 17.5 20 25 30 40 50 60 70 80 90

15-18”Forecast

7-10”Forecast

15-22”Actual

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Observed27 Km Operational NWP

Data Denial NWP

• 6 Feb: Models without PM data under-forecasted snow totals:

– Operational forecast shows paralyzing event

– Data Denial • Did not forecast paralyzing

event in DC— at least 10” too low at Day 5

• Low confidence in extreme snowfall at this point

– Future errors of this scale could

result in: • Aircraft and airline passengers

stranded• Ground commerce halted with

no mitigation plans• Population unprepared for

paralyzing snow-depth

Wash DC 5-day Forecast:- With Data: Historical, paralyzing event- Data Denial: Significant; but not

paralyzing

15-18”Forecast

7-10”Forecast

15-22”Actual

Results24 Hr Accumulated Precipitation Totals for 6 Feb (am)

5 Day Forecast

Forecast Period: 5 Feb (am) – 6 Feb (am)

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Data Denial NWP


– Operational forecast still superior• Increasing confidence in the

forecast for major snow event

– Data Denial forecast• Some improvement in snow

forecast in DC area• Still under-forecasting total

precipitation maximum in VA and Carolinas by 50%

15-18”Forecast

12-15”Forecast

Wash DC 4-day Forecast:- With Data: Historical, paralyzing event- Data Denial: Significant event

15-22”Actual

Results 24 Hr Accumulated Precipitation Totals for 6 Feb (am)

4 Day Forecast


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Data Denial NWP


– Operational forecast • Shows lower snowfall totals in DC and

surrounding area than previous model run but still superior to data denial

• Paralyzing event just south of DC• Confidence in forecast for a major

snow event still high

– Data Denial• Lower forecast snowfall totals –

decreased confidence in extreme event affecting Delmarva area

• Still under-forecasting total precipitation maximum in VA and Carolinas by 50%

Wash DC 3-day Forecast:- With Data: Significant Event DC; paralyzing event south- Data Denial: Significant Event

15-22”Actual

Results 24 Hr Accumulated Precipitation Totals for 6 Feb (am)

3 Day Forecast


Case Study 1: Heavy Rainfall Event in Southern US February 5, 2010

Forecast comparison using NOAA’s Polar-orbiting Operational Environmental Satellite data

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Observed Precipitation1 day forecast with all NOAA

orbiting satellite data

24 Hr Accumulated Precipitation Totals (inches) for 5 Feb (am)

1 day forecast without NOAA afternoon satellite data

Result: Up to a 50% error increase in precipitation rates in southern USImpacts: Future errors of this scale could result in flood forecast error providing less

time for population to react and increasing risk to life and property (hours vs days)

Results24 Hr Accumulated Precipitation Totals for 5 Feb (am)

One-day

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Data Denial NWP

• Up to a 50% error in precipitation rates and areal coverage in southern US

– Future flood forecasts could be negatively impacted—less time for population to react increasing risk to life and property

Forecast Period: 4 Feb (am) – 5 Feb (pm)

Case Study 1: Conclusion• Accurate 3-, 4-, 5-day forecasts of the Feb 5-6 2010 East Coast

Storms with PM satellite data mitigated effects on population and commerce– Had PM satellite data not been available less effective mitigation would

have been possible

• NWS alerted, with enough advance warning to take action:– Communities and Individual Citizens– State Governments and Emergency Managers– FAA and Commercial Airlines; – Surface Transportation Industry; – Schools; – Power Industry

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Case Study 2: NYC and New England Blizzard of Dec 26-27, 2010

96-hr Forecasts of Sea-Level PressureValid for 12Z27Dec2010

operational Data Denial

72-hr Forecasts of Sea-Level PressureValid for 12Z27Dec2010


24-hr Accumulated Precipitation 12Z 26Dec2010 ~ 12Z 27Dec2010

3.5 - Day Forecast “Denial” missed

24-hr Accumulated Precipitation 12Z 26Dec2010 ~ 12Z 27Dec2010

3 - Day ForecastBoth captured the storm wellDenial underpredicted

Case Study 2: Conclusion

• For forecasts extending back to 3 and 4 days the “Data Denial” experiment under-predicted the storm that hit the NYC area. The “operational” forecast captured this storm in most of the cycles, though in a couple of cycles the storm was too weak and too far to the east.

• For forecasts extending back to 3 and 4 days, the coastal low pressure system in the “Data Denial” experiment was much weaker than that in the “operational” run.

• For forecasts shorter than 2.5 (I would say 3) days, both the “Operational” and “Data Denial” captured the storm quite well, both slightly over-predicting the snowfall along the East Coast. These good forecasts were likely the result of the good RAOB coverage over North America upstream of the region of rapid cyclogenesis

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Case Study 3 : Northern Pacific Alaskan Coastal Storm, April 6-7, 2011

A significant storm occurred on April 6-7, 2011. It affected the Bering Sea, west coast of Alaska, south central Alaska, and portions of the interior. Damaging winds, blizzard condition, dangerous seas and sea ice conditions, and severe turbulence from hurricane force storm occurred in conjunction with this storm. Wind gust of 110 MPH (~50 m/s) was observed around 4 PM local time on 04/06/2011 ( 1 AM UTC on 04/07/2011).

96-hr Forecasts Valid for 12Z 7Apr2011


72-hr Forecasts Valid for 12Z 7Apr2011



• Local Impact over the Bering Sea region: the data-denial experiment did not show any systematic difference from the operational model. Storm tracks, sea-level pressure, surface winds and precipitation from the data-denial experiment are similar to those of the operational model.

• Hemispheric Large-Scale Impact: the data-denial experiment is not significantly different from the operational model except that it has larger wind RMS errors.

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Case Study 4 : Tornado Outbreak April 14-16, 2011

GSF 6-day Forecast for CAPE on April 14, 2011GSF Forecasts of Convective Available Potential Energy (CAPE) for April 14, 2011 indicate similar 6 day outlook for severe storms over the United States whether p.m. polar satellite data is included (top) or not (bottom).


• Briefly, no impact (refer to tornado two-pager to elaborate)

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Case Study 5 : Tornado Outbreak April 25-28, 2011

An extremely large and violent tornado outbreak, the largest in United States history and popularly known as the 2011 Super Outbreak, occurred from April 25 to 28, 2011. The outbreak affected the Southern, Midwestern, and Northeastern United States, leaving catastrophic destruction in its wake, especially across the state of Alabama. It produced destructive tornadoes in Alabama, Arkansas, Georgia, Mississippi, North Carolina, Tennessee, and Virginia, and affected several other areas throughout the Southern and Eastern United States with a total of 332 tornadoes confirmed in 21 states from Texas to New York and even isolated tornadoes in Canada. Widespread and destructive tornadoes occurred on each day of the outbreak, with April 27 being among the most prolific and destructive tornado days in United States history.

24-hr Accumulated Precip from 12Z 26Apr2011 to 12Z 27Apr2011

Day-7 Day-6

Day-5 Day-4

24-hr Accumulated Precip from 12Z 26Apr2011 to 12Z 27Apr2011

Day-3 Day-2

Day-1

Not much difference between the control and data denial run. Both made good forecasts.

Forecasts from Different Cycles Valid at 00Z 28Apr2011

Day-7Day-6

Day-5Day-4

Forecasts from Different Cycles Valid at 00Z 27Apr2011

Day-3Day-2

Day-1

Not much difference between the control and data denial run. Both made good forecasts starting from day-5 forecasts.


• Little Impact from loss od p.m. satellite data: Both the control and experimental data-denial runs made good forecasts of precipitation and cyclone tracks over the central to eastern US five days back from the 27-28 April 2001 tornado outbreaks.

• Hemispheric mean verification statistics such as AC and RMSE of the data denial run are slightly worse than in the control run.

• The differences of CAPE at the lowest 180 hPa above ground and Storm Relative Helicity in the lowest 3 kilometers between the control run and data-denial run are small for all forecast time up to 168 hours.

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Summary• Five Data Denial Studies have been conducted to

help evaluate the implications of a gap in afternoon polar satellite coverage

• Forecasts at 3 days & longer of significant weather episodes made w/o p.m. satellite data were– Significantly degraded in two cases– Largely unchanged in three cases

• Critical atmospheric signals detected by other observations

• These results are consistent with previous observation sensitivity studies

• Results underscore the need for continuity of both afternoon and morning polar satellite coverage

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Impact of US Polar Orbital Satellite Data Loss on Nation’s High Impact Weather Forecast Capability: Summary of Recent Data Denial Experiments Environmental