01.03.2013 Views

International Polar Year 2007–2008 - WMO

International Polar Year 2007–2008 - WMO

International Polar Year 2007–2008 - WMO

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

148<br />

IPY 20 07–20 08<br />

Fig. 2.1-9. Sea-level<br />

pressure (black<br />

contours) and 10<br />

m wind speed<br />

exceeding 10 m/s<br />

(coloured shading) for<br />

18 UTC 4 March 2008,<br />

for 24-hour forecasts<br />

from 18 UTC 3 March<br />

2008 containing (a)<br />

routine and targeted<br />

observations, (b) only<br />

routine observations<br />

and (c) ECMWF<br />

analysis.<br />

(Kristjansson et al., submitted)<br />

huge errors both in strength and position. In the<br />

former case, targeting observations by the aircraft in<br />

sensitive areas led to improvements in predicted track<br />

and intensity of the polar low. Fig. 2.1-9 shows that the<br />

forecast containing targeted observations from 18<br />

UTC 4 March 2008 improves the polar low position and<br />

strength, although the region of strong winds extends<br />

too far south compared to the analysis. Further work<br />

is underway to confirm the impact of the targeted<br />

sondes on the forecast and the reasons for this impact.<br />

Thorpex Arctic Weather and Environmental<br />

Prediction Initiative (TAWEPI) is a science and research<br />

project partly funded by the Government of Canada<br />

Program of the <strong>International</strong> <strong>Polar</strong> <strong>Year</strong>. The primary<br />

objective of TAWEPI is to improve the Environment<br />

Canada’s NWP capacity over the Arctic during the IPY<br />

observational period and beyond. TAWEPI’s research<br />

activities started in April 2007. A research version<br />

of the regional GEM model, covering the Arctic<br />

basin and surroundings is being used to study the<br />

representation of radiative and cloud processes in<br />

weather forecasts. A multi-layer snow model coupled<br />

to sea-ice and blowing-snow parameterizations,<br />

describing processes over the various types of surfaces<br />

of the Arctic environment, was tested and evaluated.<br />

A methodology to validate model forecasts of cloud<br />

and radiation using satellite hyperspectral radiances<br />

was developed. Climatology of the sensitivity of the<br />

Arctic weather to disturbances originated elsewhere<br />

was generated and archived for the IPY period of<br />

<strong>2007–2008</strong>. A state-of-the-science sea-ice model is<br />

being adjusted to improve the sea-ice representation<br />

in the Arctic (Ayrton Zadra, Environment Canada, pers.<br />

comm., see www.ec.gc.ca/envirozine).<br />

The IPY-THORPEX cluster projects have<br />

demonstrated that improvements in NWP for<br />

polar regions are possible and have increased our<br />

understanding of how to improve models and how<br />

to use data from the Arctic; they also deepen our<br />

understanding of the physical processes involved.<br />

In particular they have acquired data for improving<br />

physical parameterization in NWP models (-clouds,<br />

microphysics, surface fluxes); improved assimilation<br />

techniques for high latitudes with emphasis on<br />

satellite data; increased our understanding on<br />

the effect of the use of ensemble simulations for<br />

high latitudes; increased our understanding of the<br />

effect of targeting in high latitudes; increased our<br />

understanding of high-latitude dynamics and highimpact<br />

weather phenomena; demonstrated the effect<br />

of new instruments; and demonstrated the effect of<br />

increased Arctic and Antarctic observations for local<br />

and extratropical NWP forecasting.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!