Regional Climate Studies
Prof. dr. Nicole van Lipzig
Research conducted in the Regional Climate Studies (RCS) group aims at an improved understanding of climate processes and feedback mechanisms acting at the regional to local scale. For this purpose, advanced high-resolution regional climate models are applied to different regions of the world and combined with the analysis of ground-based and satellite based observations. An important part of our work covers the evaluation and improvement of these models. The main topics which are investigated are surface-atmosphere interactions, urban climate, polar climate and climate scenarios for the future.
Temperature in cities tends to be higher than in their natural surroundings, especially during the night. Besides this well-known urban heat-island effect, urbanisation also leads to other `urban climate' features such as an increased atmospheric turbulence, reduced wind speeds and local circulations (e.g. `city breeze'). Some of these effects have a considerable impact on human health in cities where many people live. For instance, the reduction of nocturnal cooling in cities can be problematic during heat waves. Air quality in cities are affected as well during ozone peaks or smog episodes. Due to the global increase in urbanisation and the more extreme weather lying ahead of us, the impact of urbanisation on the climate system is expected to become more severe as well. The RCS group contributes to this topic by improving of the representation of built environment in a regional climate model, assessing its impact on urban air-quality, prediction of the urban climate in the future and improving the understanding the behaviour of vegetation within the built-up environment. The latter is important in the framework of Climate Sensitive Urban Design (CSUD), which tends towards thermally comfortable and more sustainable urban environments by enhancing positive natural and man-made features.
Changes in land use, such as deforestation, agricultural practices and forest management, are important drivers of regional climate change. Besides their biogeochemical impact (release of carbon stocks), these changes also affect the exchange of heat and moisture between the surface and the atmosphere. An improved assessment and understanding of these biogeophysical processes are the focus of our research group. Several large-scale changes in the land and sea use are currently studied: Firstly the climatological impact of deforestation in the Congo basin (Africa), which is expected to be substantial over the coming decades due to increasing demand for agricultural land. Secondly the quantification and understanding of the biogeophysical role of forest management in Europe in mitigating climate change. This study includes the whole forest management spectrum ranging from short rotation coppice to old-growth forests. Thirdly the climatic effect of a change in sea use, due to large-scale offshore wind farm deployment, expected for the Atlantic, North Sea and Baltic Sea. Fourthly, research is conducted to enhance the understanding of the role of lakes in the climate system, and to improve regional climate projections over the African Great Lakes region. The latter work contributes to a larger study of the effects of climate change in and around lake Kivu (East Africa).
It is of critical importance to better understand key atmospheric processes in the polar climate system. Both cloud processes and the surface albedo of the ice sheets are recognised as key elements in the climate system. A persistent drop in the surface albedo of the Greenland ice sheet has been observed in satellite data, which strongly enhances the absorption of solar radiation. In addition, little is known about the interaction between clouds, precipitation and aerosols in the Antarctic. This is unfortunate, as the Antarctic and Greenland ice sheet are expected to become the dominant contributor to sea level rise in the 21st century. Since precipitation is the only source of mass to the ice sheets, and precipitation and clouds are closely connected, an improved insight in these processes is essential. The RCS group focuses on modelling and observing surface albedo, clouds and precipitation, and studies their effect on the surface energy balance of the ice sheets. For this purpose, the RCS group makes extensive use of satellite data, ground observations and regional climate models. Moreover, in 2009 the RCS group installed a unique cloud observatory at the Belgian Antarctic station Princess Elisabeth.
The emission of greenhouse gasses and pollutants from a variety of sources and activities has a severe impact on climate and air quality. Societies are becoming increasingly aware of this impact and the need for mitigation strategies. Therefore, there is a growing request from society for climate and air quality services, i.e. an effective dissemination of information to the general public, decision-makers or a specific user. The RCS group contributes to the development of model capacity in Belgium. This includes increasing the horizontal model resolution up to the kilometer scale to facilitate climate change impact studies. Within several projects, the added value of this high resolution is investigated both for climate and air quality projections for the future. Key-processes that play a role in establishing climate sensitivity are studied. The modelling studies are complemented by statistical downscaling techniques that enable insight in the uncertainty (spread) of the climate change signal.