Polar
View is an initiative of the European Space Agency and the European
Commission to make Earth Observation (EO) services more accessible and
affordable to anyone interested in the Northern and Southern Polar
Regions. Within Polar View SMHI makes medium range ice and SST
forecasts for the Baltic Sea with the circulation model HIROMB. The
model is forced with atmospheric model data from the European Centre
for Medium-Range Weather Forecasts (ECMWF). Data assimilation of ice parameters
based on products made from satellite images, as well as assimilation
of temperature and salinity data from other sources are used in HIROMB when
available.
June 2010
The ice forecasts will resume after the summer.
NEW! October 2009
The deterministic forecast length has been increased from 15
days to 4 weeks, once every week. The forecasts are updated early
every Friday morning and are presented as weekly mean values.
The forecast reference time is always 00 UTC every Thursday.
NEW! November 2008
The deterministic forecast length has been increased from 10 to 15
days. Similarly, the ensemble forecast length has been increased from
7 to 12 days.
About the forecasts
Forecasts of different ice parameters and Sea-Surface Temperature (SST)
are shown. The forecasts are updated once daily around 15:00 UTC. The
quality of the forecasts will be evaluated during the project period,
and improvements will be made in the meantime. Any comments on the
forecast quality or other feedback can be mailed to Lars.Axell[at]smhi.se.
Two types of forecasts are presented:
Deterministic forecasts are produced using a single forecast model. The initial and boundary conditions used for the forecasts are best guesses at the start time of the forecasts. The advantage of deterministic forecasts are that they are model consistent. However, depending on the circumstances the forecasts may experience some "jumpiness" from day to day due to changing weather conditions, which may lead to a decreased trust in the forecasts. In addition, it is usually difficult to judge the uncertainty of deterministic forecasts.
Ensamble forecasts take uncertainties in the forecasts into account to be able to estimate errors. A number of slightly different forecasts are produced, which may differ in terms of initial conditions, boundary conditions, or model physics. For Polar View, SMHI uses 20 different forecasts in the ensamble. These are produced by using five slightly different initial conditions for ice concentration and level ice thickness, as well as four slightly different forcings (lagged ensambles from ECMWF). By analyzing these forecasts it is possible to estimate probabilities of various occurrences, e.g., the probability of ice concentration larger than 80 % in a certain area. Deterministic products such as ensemble means and standard deviations may also be calculated.
IMPORTANT NOTICE!
This
website is so far only a test site. It is not yet fully operational and
data can be missing or be posted late without any further notice.
You could also visit FMI's Polar View product site
for 48 hour ice forecasts and ice thickness charts.