Better air and ground data can help predict deadly heatwaves
The rise in frequency and severity of extreme weather events worldwide is the most apparent consequence of global warming. Today, ensuring accurate and reliable climate monitoring and forecasting has become paramount. Contributing to the advance of climate modelling, the CONFESS project has made groundbreaking strides, supporting the Copernicus Climate Change Service (C3S) in providing authoritative information about the past, present and future climate in Europe and the world. Specifically, the project has enhanced the representation of tropospheric aerosols in climate models and has identified and harmonised different data sets of land use, land cover and vegetation. “The CONFESS developments and exploration of their impacts on seasonal and decadal predictions have contributed to advancing the state-of-the-art capabilities for weather and climate predictions and the next generation of reanalysis, in areas urgently needed for adaptation to climate change,” says Magdalena Alonso Balmaseda, CONFESS project coordinator.
Tracking aerosol impacts
A major step of the project relates to the treatment of tropospheric aerosols – tiny particles suspended in the Earth’s lower atmosphere – in reanalysis and seasonal forecasts. CONFESS produced a multi-decadal record of time-varying tropospheric aerosols and thoroughly evaluated it in long-term climate simulations, seasonal reforecasts and medium-range forecasts. The work offers synergies with the Copernicus Atmosphere Monitoring Service (CAMS). Due to its high quality, this record will be incorporated into the next generation of seasonal forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) and into the upcoming C3S atmospheric reanalyses. For instance, by analysing the record, scientists can observe the reduction in sulphates from industrial emissions in Europe, contrasted with an increase in these emissions in China, India and the Middle East. “The temporal changes in aerosols impact not only the local radiation balance, directly influencing surface temperature, but also large-scale atmospheric circulation patterns. The analysis of the results highlights the need to include the indirect effects of aerosols in the models used for reanalysis and seasonal forecasts,” explains Balmaseda.
Harmonising land data
Additionally, CONFESS has successfully identified and harmonised different data sets related to land use, land cover and vegetation. By implementing them in different climate models, researchers were able to obtain, for the first time, a quantitative assessment of the impact of time-varying land properties in multi-year land simulations and seasonal forecasts. The assessment revealed that these properties, particularly vegetation, significantly influence trends and extremes in surface temperature. An example is the intense and long-lasting heatwave experienced by Europe in the summer of 2003. The hot, dry conditions decreased the vegetation fraction, which in turn contributed to the intensity of the heat. “Including time-varying vegetation in the models used for seasonal forecasts should result in improved predictions of temperature extremes. Results also indicate that vegetation appears to mitigate or enhance long-term warming trends in some regions of the globe – a critical aspect for climate change adaptation and mitigation,” notes Balmaseda. Further research is still needed before incorporating land properties into the C3S system, but the most recent period of the new data sets will be used in the ECMWF operational prediction systems. The developments accomplished by CONFESS also form the foundation for the CERISE project, which aims to improve the quality of the C3S reanalysis and seasonal forecast systems in terms of land-atmosphere assimilation and coupling.
Keywords
CONFESS, seasonal forecast, climate change, tropospheric aerosols, climate monitoring
