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Atmospheric
in ProClim
TITLE OF modeling
PRESENTATION
by
by
Anne D.
Sandvik
N.N.
ProClim, WP 2: Water mass formation on shelves
• Atmospheric modeling
”Perform nonhydrostatic 1-2 km resolution model studies of Storfjorden and the western
Barents Sea, and make the atmospheric model available for coupling to the ice-ocean model”
Motivation
 HINDCAST wind (75 km) and observations from Hopen
 High-resolution model estimated wind
 Impact on the circulation and Polynia dynamics
due to resolution in the wind forcing?
 Coupled ice-ocean-atmospheric model
Preliminary workplan:
I.
4 km atmospheric forcing 1998-1999
(Ragnheid, MM5 -> BOM)
II. Validation against synoptic observations, 2003
III. Case study polar low, March 11, 2003
IV. Sensitivity to ice cover (in Storfjorden)
V. MM5 - ROMS
MM5, NCAR/Penn State mesoscale model
• Non – hydrostatic
• Polar mode
• 23 vertical sigma level (40m – 15 km)
• One way nesting 12 -> 4km
• Initial and lateral boundary values (ECMWF)
Model domain: 12 -> 4 km ( BOM)
Observations from met.no
Ny-Ålesund
Longyearbyen
Hopen
Wind observations, Hopen 1998 – 1/9 2002
The synoptic weather station at Hopen is located beneath a gap
or pass in the mountain at the eastern side of the island.
The station elevation is about 10 m. Hopen is about 33 km long
and 1,5 - 2 km wide and its orientation on the map is SSW – NNE.
Due to the local topography wind measurements are probably to
low when the wind direction are from SW (220) and clockwise
through west (40-60), with a possibly small secondary maximum
when the wind direction are from west and the flow comes
through the gap.
 Hopen is not represented in the MM5 4 km domain
MM5 estimated temperature and wind
1/8 – 1/12, 1998
1/1 – 1/5, 1999
Temperature at Hopen, observation 2 m asl (red line) and model estimated temperature
about 38 m agl (blue line). The mean value and standard deviation of the observations
are indicated with the green and black dashed lines respectively.
Wind speed, Hopen
Wind speed at Hopen, observation 10 m asl (red line) and model estimated wind
about 38 m agl (blue line). The mean value and standard deviation of the observations
are indicated with the green and black dashed lines respectively.
How representative is Hopen for the Storfjorden area?
Hopen – Storfjorden, Sep., 1998
Model estimated temperatur and wind at Hopen (red line) and at a positipn
inside Storfjorden (blue line)
Hopen – Storfjorden, Sep., 1998
Correlation coefficient for temperature (left) and wind speed (right) estimated between the MM5 Hopen gridpoint and all
other gridpoints in the 4 km domain.
Hopen – Storfjorden, Sep., 1998
Correlation coefficient for wind direction estimated between the
MM5 Hopen gridpoint and all other gridpoints in the 4 km
domain.
Summary subtask 1
Hopen obs – Hopen MM5
Hopen MM5 – Storfjorden MM5
BOM with HINDCAST wind (75 km)
BOM with MM5 wind, Ragnheid
Validation of MM5 against available data in Arctic,
March 2003
Temperature, wind speed and direction:
Hopen
Longyearbyen
Ny-Ålesund
Model domain: 12 -> 4 km
Observations from NMI
Ny-Ålesund
Longyearbyen
Hopen
Ice cover from ECMWF
Wind, 9/3 – 03, 1200 UTC
ECMWF interpolated to 4 km
MM5 domain
MM5 estimated wind
Temperature, March 2003
Temperature at Hopen, observation 2 m asl (blue line) and model estimated temperature
about 38 m agl (red line). The mean value and standard deviation of the observations
are indicated with the green and black dashed lines respectively.
Wind speed, March 2003
Wind speed at Hopen, observation 10 m asl (blue line) and model estimated wind
about 38 m agl (red line). The mean value and standard deviation of the observations
are indicated with the green and black dashed lines respectively
Temperature and wind speed, March 2003
Wind speed and direction, March 2003
Wind roses for March 2003, observations in the left panel and ”MM5 Hopen” in right panel. The direction is divided into 24,
15 deg bins. The numbers on the inner and outher circle show the % at the given direction. Blue shows wind speeds from
0 – 5 m/s, pink from 5 – 10 m/s and yellow from 10 – 15 m/s.
Polar low, March 11, 2003
Polar low, March 11, 2003
Work in progress:
Case study polar low, March 11, 2003
Sensitivity to ice cover
Atmospheric boundary layer over ice
Method for picking interesting cases from
ERA-40
Work in progress:
 MM5 -> BOM
 MM5 -> ROMS(ICE) -> MM5 -> ROMS(ICE)
Input?