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 western Barents 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 (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 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/ 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, /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 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 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: Hopen Longyearbyen Ny-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

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?