Research - Biogeophysics & Climatology Introduction to Biogeophysics and Climatology

The atmosphere and the climate both have an effect on nature and society, but also the inverse is true: the natural world and human society affect the climate. In the research field of Biogeophysics & Climatology we use observational data to study the interaction between nature and climate, as well as its effects both today and in the future. Our work spans over wide ranges in both space and time. To better understand the complex interactions involved, and to allow us to draw more general conclusions about the phenomena under study, we develop and apply different simulation models in our analysis.

Biogeophysics is concerned with how the soil, plants and atmosphere interact with each other through the transport and exchange of energy and various compounds such as carbon dioxide. This mutual interaction takes many different forms. One example is that the amount of water that evaporates from vegetation is dependent both on the structure and texture of the ground surface (compare a tall forest with a short grass field) as well as the specific properties of the plants, such as their ability to regulate the size of their microscopic openings (stomata) on the leaf surfaces.

But the evaporation is also controlled by the amount of water available in the soil - and this is affected by the precipitation. Another important question related to climate is how much greenhouse gases are released into or taken up from the atmosphere. Through photosynthesis plants absorb carbon dioxide from the air, but at the same time plants and other living organisms actually release carbon dioxide back into the atmosphere through a process known as respiration. The balance between these two processes thus decides whether a given ecosystem is a sink or a source of carbon dioxide (as seen from the point of view of the atmosphere).

The measurement techniques that we use are based on micrometeorological theories of how the atmosphere works. In order to measure the exchange of mass (such as H2O and CO2) and energy from an entire ecosystem, we have to place our instruments high up in the air above the ground, for instance fixing them to a high tower. With such measurement setups, the mass and energy exchange within a radius of hundreds of meters, or even a few kilometers, can be probed. In some cases, we also use instrumentation onboard a small, specially equipped aircraft, which means we can study processes over even larger areas.

In a longer time perspective, we study the effects on the local environment of both the "normal" state of the climate system as well as extreme deviations from this. For instance, we are trying to find out more about the long-term effects of variations and changes in climatological factors, such as air temperature, precipitation and wind, on plants and animals in forest ecosystems. A major research effort is concentrated on the impact of storms on forests - not just direct consequences like windthrows, but also more indirect effects such as the possibility of insect infestations.

A good example is the spruce bark beetle, which reproduction benefits greatly from the high availability of storm-felled timber. By combining meteorological observations with data on forest damage it becomes possible to see that both changes in climate and in forestry practices have an impact on the severity of forest damage. This type of knowledge is very important for politicians and policy makers who are responsible for adapting our society to the ongoing climate change.

Information about how the climate has varied in the past can be found both in geological and biological "archives" (such as sediment and ice cores, pollen and tree rings) and, for the most recent history, as observational datasets from meteorological instruments. We primarily work with the so-called instrumental period, which at best covers the last 300 years. Climate modelling has become and increasingly important field of research, spurred on by the desire to project the future climate, given different scenarios of industrial and societal development on a global scale. Such projections are of great interest and importance to social planning. The department has strong links with the Rossby climate modelling Centre of the Swedish Meteorological and Hydrological Institute (SMHI).

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