Polar Meteorology Group Byrd Polar Research Center The

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio A High-Resolution Arctic System Reanalysis David H. Bromwich 1, 2 and Keith M. Hines 1 1 Polar Meteorology Group Byrd Polar Research Center The Ohio State University Columbus, Ohio, USA 2 Atmospheric Sciences Program Department of Geography The Ohio State University Columbus, Ohio, USA S 4 D Workshop Paris, France

Arctic System Reanalysis (ASR) 1. Rapid climate change appears to be happening in the Arctic. A more comprehensive picture of the coupled atmosphere/land surface/ ocean interactions is needed. 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 would provide a community focus including the atmosphere, land surface and sea ice communities. 5. The ASR would provide a convenient synthesis of Arctic field programs (SHEBA, LAII/ATLAS, ARM, . . . )

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio ASR Outline A physically-consistent integration of Arctic data enhanced observations of the Sustained Arctic Observing Network (SAON) Participants: Ohio State University - Byrd Polar Research Center (BPRC) - and Ohio Supercomputer Center (OSC) National Center Atmospheric Research (NCAR) University of Colorado University of Illinois University of Alaska Fairbanks High resolution in space (20 km) and time (3 hours) Begin with years 2000 -2010 (EOS coverage) Supported NSF as an IPY project S 4 Dby Workshop Paris, France

Issues with Observations and 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 h. Pa. [from visualization package of NOAA Climate Diagnostics Center] The Figure shows an intense storm depicted in the NCEP/NCAR reanalysis for 19 October 2004. This storm, which led to flooding of downtown Nome, Alaska, has a central pressure of 949 h. Pa in the reanalysis. The actual central pressure deduced by the National Weather Service was as low as 941 h. Pa.

Arctic Clouds / Radiation

Radiation and Cloud Differences in the Arctic solar and cloud fraction at Barrow (June 2001): ERA 40 (red) vs ARM/NSA (black)

Radiation and Cloud Differences in the Arctic longwave and cloud fraction at Barrow (June 2001): ERA 40 (red) vs ARM/NSA (black)

New data sources: Important developments in Data Assimilation WRF is well represented • MODIS winds – Tests underway • AIRS • COSMIC – Radio occultation soundings from GPS satellites • ATOVS

Typical distribution of COSMIC GPS radio occultation soundings (green dots) over a 24 -hour period over the Arctic.

Mesoscale Modeling High Resolution Depictions

Precipitation over Iceland from Polar MM 5 Annual mean precipitation, 1991 -2000 Observed annual mean precipitation derived from polar MM 5 V 3. 5 (cm). Contour interval = 20 cm. MM 5 is (mm) derived from station data, driven at the boundaries by ECMWF contour interval = 200 mm operational analyses. Importance of high-resolution simulations and skill of numerical models in high latitudes

WRF – Weather Research and Forecasting model • Base model for ASR • Polar WRF – Polar-optimized version has been developed (Ohio State) – Tested for Greenland – Tested for Antarctica – Testing for Sheba – Testing for Arctic land • Data Assimilation (NCAR) • Land surface processes (NCAR)

On the Impact of MODIS Winds on AMPS WRF Forecasts Jordan G. Powers, Syed R. H. Rizvi, and Michael G. Duda Mesoscale and Microscale Meteorology Division National Center for Atmospheric Research Boulder, Colorado, USA

MODIS Wind Retrieval Filtering Unfiltered— ALL Filtered— MOD 1 0000 UTC 15 May 2004 Init

III. Simulations and Results • WRF Experiments Init: 0000 UTC 15 May 2004 – First-guess and BCs: 1 GFS – Standard AMPS data: Sfc repts, AWS, upper-air, ships, buoys, cloud-track winds CTRL No data assimilation ALL 3 DVAR w/std AMPS data + all MODIS MODQC 3 DVAR w/std AMPS data + MODIS FILTER/QC subset EXMOD 3 DVAR w/std AMPS data only • MM 5 Simulation AMPS MM 5 3 DVAR w/std AMPS data only

Experiment Results— WRF Sfc Winds (ms-1) SLP (h. Pa) L ms-1 34 34 • 25 L L STD MOD 1 L CTRL 2300 UTC 15 May (Hr 23) ALL 25

ASR High Resolution Domain Outer Grid: ~45 km resolution Inner Grid: ~15 km resolution Vertical Grid: ~60 levels Inner Grid includes Arctic river basins