TAWEPI's research activities started in April 2007 and large progress has been made in the development of Polar-GEM since then. A new version of the CMC regional NWP model became operational in the spring of 2009, including a northward extension of its high-resolution domain, which now covers most of the Arctic and shares various features with Polar-GEM. A research version of the model is being used to study the representation of radiative and cloud processes in weather forecasts. A multi-layer snow model coupled to sea-ice and blowing-snow parameterizations, describing processes over the various types of surfaces of the Arctic environment, such as sea-ice, tundra, glaciers and ice caps, was tested and evaluated. A methodology to validate model forecasts of cloud and radiation using satellite hyperspectral radiances was developed. Using a stratospheric extension of the GEM model, analyses of the stratosphere were extended and now cover the entire IPY period of 2007/2009, including estimates of the ozone field.