Disaster preparationClimate models still struggle with medium- term climate forecasts
Scientists have evaluated twenty-three climate models and concluded that there is still a long way to go before reliable regional predictions can be made on seasonal to decadal time scales; none of the models evaluated is able today to forecast the weather-determining patterns of high and low pressure areas such that the probability of a cold winter or a dry summer can be reliably predicted
How well are the most important climate models able to predict the weather conditions for the coming year or even the next decade? The Potsdam scientists Dr. Dörthe Handorf and Prof. Dr. Klaus Dethloff from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) have evaluated twenty-three climate models and published their results in the current issue of the international scientific journal Tellus A. Their conclusion: there is still a long way to go before reliable regional predictions can be made on seasonal to decadal time scales. None of the models evaluated is able today to forecast the weather-determining patterns of high and low pressure areas such that the probability of a cold winter or a dry summer can be reliably predicted.
An AWI release reports that the most important questions currently being asked in climate research concern the impact of global climate change regionally and in the medium term. These are the subjects of national and international research programs and will play a large role in the next world climate report because societies having to adjust to climatic changes should know which specific changes they must expect. For the energy or agricultural sector, for example, it would be enormously important to know if the weather conditions prevailing in a region in the medium term could be reliably predicted. Against this background, the prediction quality of current climate models for the period of seasons to a decade is of great importance.
The Earth’s weather is significantly determined by large-scale circulation patterns of the atmosphere.
One example of this is the North Atlantic oscillation which influences the strength and location of the westerly winds over the North Atlantic and therefore determines the tracks of the low pressure systems over North and Central Europe. Circulation patterns of this nature, also referred to as “teleconnection,” are distributed over the entire globe and determine the spatial and temporal distribution of areas of high and low pressure over large distances. Scientists speak here of the formation of “meteorological centers of action” which determine the weather of an entire region. In the case of the North Atlantic oscillation, these are the known weather centres of the “Icelandic Low” and the “Azores High.”
“Short-term weather forecasts are now very reliable. The problems for seasonal and decadal, that is medium-term, predictions refer to the enormous variability and the broad range of feedback effects to which atmospheric
