The aim of my research was to enhance the understanding of how clouds and their macro and microphysical properties interact with boundary-layer dynamics and radative energy fluxes. This is shaping the currect climate and will be an important factor in the change of the future climate.

My goal was to understand the connection between the radiation budget at the Arctic surface and the amount of clouds in the boundary layer above. I studied the results from the soundings measurements made during 2008. I analyzed the meteorlogical parameters, such as temperature, wind profiles and pressure and also looked at turbulent fluxes and vertical profiles of clouds.

As a first step I've compared the ASCOS data with the results from The Arctic System Reanalysis (ASR) from The Polar Meteorology Group of the Byrd Polar Research Center at The Ohio State University. The atmopheric parameterization is developed from their Polar WRF model (Weather and Research Forecasting). The reanalysis can in this way be verified using observations that have not been taken into account earlier. ASR has a high resolution in space (10 km) and time (3 h) of the atmosphere-sea ice-land surface system of the Arctic. The analysis provide gridded fields of temperature, radiation and wind and serve as a driver in coupled ice-ocean, land surface and other models. This also gave me an oppurtunity to get used to the different datasets.

There are three key issues within the boundary layer that will be studied. One question is how the cloud-and surface-generated turbulence help to shape the planetary boundary layer (PBL) structure. From observations, it can be seen that either the clouds are near the surface generated by turbulent eddies and overturning from the surface or they are located higher up in the troposphere (1 km), created by unknown mechanisms. There are also cases where these two situations are combined and it would be interesting to figure out how these different structures are shaped.

Another question is the coupling between cloud micro physics and cloud turbulence. What happens with the turbulence kinetic energy (TKE) relative to diffusivity at the top of the cloud? If the conditions are changed, the cloud properties chance, but the question is how and why. To study this, one can look at the bulk micro physical data from the radar and try to calculate the energy from a frequency spectrum.

The last issue has to do with the soundings. When the soundings from the ASCOS expedition were analyzed, they showed a pattern that can not be explained by the general physics behind cloud formation. The lapse rate and the dew point profile look different from case to case and the inversion has a different shape. It would be interesting to find out whether it is possible to generalize the outcome and explain the physics behind. 

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