THORPEX-Pacific Workshop Kauai, Hawaii

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio

David H. Bromwich1,2 and Keith M. Hines1

1Polar Meteorology GroupByrd Polar Research CenterThe Ohio State University

Columbus, Ohio, USA

2Atmospheric Sciences ProgramDepartment of GeographyThe Ohio State University

Columbus, Ohio, USA

Arctic IPY (2007-2009):Arctic System

Reanalysis

Arctic IPY (2007-2009):Arctic System

Reanalysis

THORPEX-Pacific Workshop Kauai, Hawaii

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio

Links Between the Pacific and ArcticLinks Between the Pacific and Arctic Aleutian Low – especially important for

winter PNA Pattern – ENSO/Wave propagation Pacific Decadal Oscillation September 2007 All-Time Minimum in

Arctic Sea Ice Extent – concentrated in the Pacific Sector

IPY (2007/9) Overlaps with Wintertime THORPEX-Pacific (Jan.-Mar. 2009)

The storm of 19 October 2004 as depicted by the NCEP/NCAR global reanalysis. Contours represent isobars of sea level pressure at increments of 3 hPa. [from visualization package of NOAA Climate Diagnostics Center]

The Figure shows an intense storm depicted in the NCEP/NCAR reanalysis for 19 October 2004. The storm led to flooding of Nome, Alaska, and has a central pressure of 949 hPa in the reanalysis. The actual central pressure deduced by the National Weather Service was as low as 941 hPa.

The Need for Improved Atmospheric Reanalyses

Arctic System Reanalysis Arctic System Reanalysis (ASR)(ASR)an NSF-Funded IPY Projectan NSF-Funded IPY Project1. Rapid climate change is occurring in the Arctic. An integrated

picture of coupled atmosphere/land surface/ ocean interactions is needed on synoptic and climatic time scales.

2. Global reanalyses encounter many problems at high latitudes. The ASR would use the best available description for Arctic processes and would enhance the existing database of Arctic observations. The ASR will be produced at improved temporal resolution and much higher spatial resolution.

3. The ASR would provide fields for which direct observation are sparse or problematic (precipitation, radiation, cloud, ...) at higher resolution than from existing reanalyses.

4. The system-oriented approach provides community focus including the atmosphere, land surface and sea ice communities.

5. The ASR will provide a convenient synthesis of Arctic field programs and integrate Pacific region observations.

ASR OutlineA physically-consistent integration of Arctic and

other Northern Hemisphere data

Current Participants:Ohio State University - Byrd Polar Research Center (BPRC)

- and Ohio Supercomputer Center (OSC)National Center Atmospheric Research (NCAR)Universities of Colorado, Illinois, and Alaska-Fairbanks

High resolution in space (<20 km) and time (3 hours)- convenient for synoptic studies

Begin with years 2000-2010 (Earth Observing System)

Also Interested:NOAA (Also provided start-up funds) NASAU.S. Department of Energy

Pressure at SHEBA Camp and Barrow January 1998

1000

1005

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1 6 11 16 21 26 31January 1998

Pre

ssu

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PWRF 2.3 SHEBAPWRF 2.3 Barrow, AlaskaSHEBA ObservationsBarrow, Alaska Observations

ASR Numerical Model: Polar WRFWeather Research and Forecasting Model

SHEBA 1997/8 Grid

January 1998 Results

Polar Optimization at theByrd Polar Research Center:Fractional sea iceSea ice albedoMorrison microphysics (2-moment)Noah LSM modificationsHeat transfer through snow and ice

ASR High Resolution Domain

Outer Grid: ~45 km resolution

Inner Grid: ~15 km resolution

Vertical Grid: ~70 levels

ASR will detail the downstreamimpacts from the Pacific sector

Numerical Experiments within the ASR Framework

• The ASR will employ modern, efficient Data Assimilation techniques.

• Observing System Experiments (OSEs) are numerical model-based experiments to test the impact of new and existing observations. Sometimes called “data denial” experiments.

• Observing System Simulation Experiments (OSSEs) are numerical experiments that test impacts of future observing systems, e.g., new satellite sensors and Automatic Weather Stations

• Determine the observations needed to optimize the Arctic observing system.

Other Considerations for the Other Considerations for the ASRASR

• Impact of Pacific weather on Alaska and Impact of Pacific weather on Alaska and the Beaufort Sea, including extreme the Beaufort Sea, including extreme eventsevents

• New and improved Data Assimilation in New and improved Data Assimilation in cloudy areascloudy areas

• Optimized numerical modeling for the Optimized numerical modeling for the Arctic (e.g., mixed-phase clouds, variable Arctic (e.g., mixed-phase clouds, variable sea ice characteristics, and realistic sea ice characteristics, and realistic Arctic land representation – e.g., Arctic land representation – e.g., permafrost)permafrost)

• Interaction of Ocean and Sea Ice Interaction of Ocean and Sea Ice communities with the Atmospheric communities with the Atmospheric ReanalysisReanalysis

THORPEX-Pacific Workshop Kauai, Hawaii

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio

Key Points for ASR and THORPEX-Pacific

Key Points for ASR and THORPEX-Pacific

Synoptic and Climate Applications Detailing Arctic features downstream of the

Pacific Sector Combining remote sensing, modeling and

in-situ observations High resolution Polar WRF simulations Advanced Data Assimilation Expansion to the 1957-2000 period? ASR Planning Meeting late February at

NCAR … consider THORPEX-Pacific contribution?