Adaptive Observations at NWS

Lacey Holland, SAIC at EMC/NCEP/NWS

Zoltan Toth, EMC/NCEP/NWS

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

Acknowledgements: Dave Emmitt, Steve Lord, Sharan Majumdar, Jon Moskaitis, Craig Bishop

Outline

• WSR results• THORPEX• TOST• Future Work

Winter Storm Reconnaissance (WSR)

• Based on collaborative research between university and gov’t agencies. EMC/NCEP/NWS established the program in 1999.

• Dropwinsonde observations taken over the 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 in areas that influence the forecast the most.

• Results show 60-80% improvement over forecast area• Operational since January 2001

How WSR targeting

happens…1. Targets selected in areas where critical winter weather events

with high forecast uncertainty may have a potentially large societal impact.

2. Sensitivity calculations performed using ETKF, and a decision is made (flight/no flight).

3. Observations are taken and used in operational analysis and forecast products by major NWP centers.

4. Verification is performed by comparing operational analyses/forecasts including the targeted data with analyses/forecasts excluding the targeted data.

54 Predetermined Flight Tracks

Data Impact and Forecast Verification

Forecast improvement (red) and degradation (blue)

Data impact

48-hr verification

Flight track with initial

impact

Verification region with impact at

48-hrs

Estimated forecast error variance reduction with possible flight tracks

Results from previous years of WSR

Surface Pressure RMS Error

Vector Wind RMS Error

From Toth et al. (1999)

Equitable Threat Score – WSR 2002

Equitable Threat Score – WSR 2003

WSR summary results

• Overall, surface pressure, winds, and precipitation forecasts improved greatly over verification area

THORPEX

• A WWRP/WMO 10 yr international program to accelerate improvements in short range (up to 3 days), medium range (3-7 days), and extended range (two weeks) weather forecasts

• Examines observing system, data assimilation, forecast procedures, and economic application issues in their complex interactions; aims at improving forecasts for high impact weather events

THORPEX Observing System Test (TOST), Pacific 2003

• First of a series of Pacific and Atlantic observation tests/campaigns in support of the WWRP/USRP THORPEX Program

• Measurements are complimentarily provided by the various ground-, airborne-, and space-based observing systems participating in the campaign, used as targeted input.

• Winter Storm Reconnaissance (WSR) used as resource to target sensitive areas for observation over northeast Pacific (N of HI), and near the California coast

Pacific TOST 2003Sensitive area at observation time

Verification disk and area of expected impact

Expected forecast error variance reduction and verification region

Sensitivity calculations for TOST 2003 flight planning

For Twin Otter(Emmitt et al.)

Future Work

• Verify precipitation forecasts for all years of WSR; introduce new metric (storm track error)

• Continue collaboration with LIDAR group (Emmitt et al.) in support of Pacific TOST or other campaigns

• Test adaptive observations technique in OSSE environment, on global scales with simulated LIDAR measurements