Transcript Arcto - Ohio State University

Polar Meteorology Group, Byrd Polar Research Center, The Ohio State University, Columbus, Ohio
A High-Resolution
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
S4D 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
S4Dby
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
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. This storm, which led to flooding of
downtown Nome, Alaska, 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.
Arctic Clouds / Radiation
Radiation and Cloud Differences in the Arctic
 solar and cloud fraction at Barrow (June 2001):
ERA40 (red) vs ARM/NSA (black)
Radiation and Cloud Differences in the Arctic
 longwave and cloud fraction at Barrow (June 2001):
ERA40 (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 MM5
Annual mean precipitation, 1991-2000
Observed annual mean precipitation derived from polar MM5 V3.5 (cm).
Contour interval = 20 cm. MM5 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— MOD1
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
3DVAR w/std AMPS data + all MODIS
MODQC
3DVAR w/std AMPS data +
MODIS FILTER/QC subset
EXMOD
3DVAR w/std AMPS data only
• MM5 Simulation
AMPS MM5
3DVAR w/std AMPS data only
Experiment Results— WRF Sfc Winds
Sfc Winds (ms-1)
SLP (hPa)
L
ms-1
ms-1
34
34
•
25
L
L
STD
MOD1
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