TITLE OF PRESENTATION

by

N.N.

Atmospheric modeling in ProClim

by

Anne D. Sandvik

• Atmospheric modeling

”Perform nonhydrostatic 1-2 km resolution model studies of Storfjorden and the westernBarents Sea, and make the atmospheric model available for coupling to the ice-ocean model”

ProClim, WP 2: Water mass formation on shelves

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

I. 4 km atmospheric forcing 1998-1999 (Ragnheid, MM5 -> BOM)

II. Validation against synoptic observations, 2003III. Case study polar low, March 11, 2003IV. Sensitivity to ice cover (in Storfjorden)V. MM5 - ROMS

Preliminary workplan:

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)

Ny-Ålesund

Longyearbyen

Hopen

Observations from met.no

Wind observations, Hopen 1998 – 1/9 2002

The synoptic weather station at Hopen is located beneath a gapor 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 tolow when the wind direction are from SW (220) and clockwisethrough west (40-60), with a possibly small secondary maximumwhen 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, 19981/1 – 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?

Model estimated temperatur and wind at Hopen (red line) and at a positipninside 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

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

BOM with HINDCAST wind (75 km)

BOM with MM5 wind, Ragnheid

Hopen MM5 – Storfjorden MM5

Validation of MM5 against available data in Arctic, March 2003

Temperature, wind speed and direction:

HopenLongyearbyenNy-Ålesund

Model domain: 12 -> 4 km

Ny-Ålesund

Longyearbyen

Hopen

Observations from NMI

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, 2003Sensitivity to ice coverAtmospheric boundary layer over iceMethod for picking interesting cases from ERA-40

Work in progress:

MM5 -> BOM

MM5 -> ROMS(ICE) -> MM5 -> ROMS(ICE)

Input?