David H. Bromwich1,2 and Keith M. Hines1

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Arctic IPY (2007-2009)Arctic System Reanalysis

• David H. Bromwich1,2 and Keith M. Hines1
• 1Polar Meteorology Group
• Byrd Polar Research Center
• The Ohio State University
• Columbus, Ohio, USA
• 2Atmospheric Sciences Program
• Department of Geography
• The Ohio State University
• Columbus, Ohio, USA

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Links 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)

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The Need for Improved Atmospheric Reanalyses
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.
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Arctic System Reanalysis (ASR)an NSF-Funded IPY
Project

• 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.

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ASR Outline
A physically-consistent integration of Arctic and
other Northern Hemisphere data
High resolution in space (lt20 km) and time (3
hours) - convenient for synoptic studies
Begin with years 2000-2010 (Earth Observing
System)
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
Also Interested NOAA (Also provided start-up
funds) NASA U.S. Department of Energy
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ASR Numerical Model Polar WRF
Weather Research and Forecasting Model
Polar Optimization at the Byrd Polar Research
Center Fractional sea ice Sea ice
albedo Morrison microphysics (2-moment) Noah LSM
modifications Heat transfer through snow and ice
SHEBA 1997/8 Grid
January 1998 Results
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ASR High Resolution Domain
Outer Grid 45 km resolution
Inner Grid 15 km resolution
Vertical Grid 70 levels
ASR will detail the downstream impacts from the
Pacific sector
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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.
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Other Considerations for the ASR

• Impact of Pacific weather on Alaska and the
  Beaufort Sea, including extreme events
• New and improved Data Assimilation in cloudy
  areas
• Optimized numerical modeling for the Arctic
  (e.g., mixed-phase clouds, variable sea ice
  characteristics, and realistic Arctic land
  representation e.g., permafrost)
• Interaction of Ocean and Sea Ice communities with
  the Atmospheric Reanalysis

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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?