Land-climate interactions and their role in the climate system
Continents and oceans are the lower boundary for the atmosphere, with which they exchange water, energy and chemical compounds such as CO2. Similar to the oceans, which significantly contribute to climate variability by storage and exchanges of heat, land areas have a strong impact on climate variability through water storage (soil moisture, groundwater, snow) and evapotranspiration. Beside its significance as water input to the atmosphere, evapotranspiration is also part of the land energy balance and is tightly coupled with CO2 assimilation from vegetation. Moreover, land cover (vegetation, bare ground, snow, ice) also impacts albedo and the radiation balance. Hence interactions between land and the climate system are manifold and strongly interconnected. As an example, soil moisture-temperature coupling has been found to be a key driver of summer temperature variability in Europe, both in present (Mediterranean) and future (Northern and Eastern Europe) climate (Seneviratne et al. 2006, Nature). Gradual changes in soil moisture-coupling take place as global warming unfolds and induces shifts of climate regimes on the continent.
Despite their key role for the climate system, land-climate interactions are still the subject of significant uncertainties (Seneviratne et al. 2010, Earth-Science Reviews). A major issue is the lack of direct observations of the relevant climate variables (soil moisture, evapotranspiration), which impedes the understanding of the associated processes and their necessary validation in climate models. Hence, a focus of our research group is the analysis of existing observations, the intercomparison and merging of observation-based datasets, and the conducting of field experiments in order to reduce uncertainties and better constrain models. In particular, we investigate the definition of indirect diagnostics for the validation of land-climate interactions in climate models.
We use several modelling tools, including regional and global climate models (COSMO-CLM, ECHAM) as well as land surface models (Community Land Model (CLM), Terra_ML), to investigate interactions between land and climate, in particular by way of sensitivity experiments. We are interested in the quantification of land-atmosphere coupling and of individual land-atmosphere feedbacks at the regional and global scale, as well as in their role relative to other drivers of climate variability (radiation, sea surface temperatures). Special areas of interests are extreme events (droughts, heat waves, heavy precipitation events), seasonal forecasting, and modifications with global warming.
- Role of land-atmosphere coupling for climate variability extreme events (NRP61 DROUGHT-CH, NCCR-Climate Phase III, EU-FP6 project CECILIA)
- Evaluation and improvement of current Earth System Models with respect to land-climate interactions (EU-FP7 EMBRACE)
- Impacts of extreme events on land carbon cycle (EU-FP7 CARBO-Extreme, SNF Sinergia Carbo-Count CH)
- Soil moisture initialization for seasonal forecasting (GLACE-2 project), drought early warning (EU-FP7 DROUGHT-R&SPI, NRP61 DROUGHT-CH)
- Coupling of COSMO-CLM model with the Community Land Model (CLM): "COSMO-CLM2". This new model allows to perform regional climate simulations including a detailed representation of vegetation processes (vegetation dynamics, phenology, plant physiology, and CO2-water interactions) (SNF Sinergia Carbo-Count CH, MAIOLICA project).
We focus on the analysis of processes at the land-atmosphere interface, based on existing data (ground observations, satellite observations, observation-based datasets, model data). We investigate in particular processes controlling soil moisture and land processes in general (droughts, vegetation, snow cover, ecosystem exchanges, land water and energy cycles) as well as land-atmosphere interactions and feedbacks. An important aspect of our research is the validation of the corresponding processes and interactions in climate and land surface models.
Activities in this area:
- Analysis of land-atmosphere coupling and land persistence based on observations and model data (NRP61 DROUGHT-CH, NCCR-Climate Phase III, EU-FP6 project CECILIA)
- Evaluation of climate models with observations (e.g. EU-FP7 EMBRACE, ETH CHIRP2, ESA Soil moisture CCI, LandFlux-EVAL initiative, FLUXNET)
- Assessment of drought development and drought-related damage in Europe and Switzerland (EU-FP7 DROUGHT-R&SPI, NRP61 DROUGHT-CH, NCCR-Climate Phase II/SwissRe)
- Analysis of extreme temperature and precipitation events in Central and Eastern Europe (EU-FP6 project CECILIA)
An important research area of our group concerns the evaluation and intercomparison of existing land datasets, as well as the development of merged datasets based on several data sources. We recently initiated an intercomparison exercise sponsored by GEWEX and ILEAPS, LandFLUX-EVAL, aimed at the evaluation of current observation-based evapotranspiration datasets and the development of a reference benchmarking dataset. Furthermore, we have the climate lead of the ESA Soil moisture Climate Change Initiative (CCI), which aims at evaluating and using soil moisture remote sensing datasets for climate research. Finally, we also maintain a diagnostic dataset (BSWB) of monthly variations in terrestrial water storage for several river basins. The BSWB estimates have been shown to compare well with available observations and are available for 37 river basins.
Since 2008, we are conducting a Switzerland-wide soil moisture measurement campaign (SwissSMEX) funded by SNF, in collaboration with Agroscope ART and MeteoSwiss. This campaign has been now expanded to forest sites, in collaboration with WSL (SwissSMEX-Veg). The data are used to assess spatio-temporal characteristics of soil moisture. Moreover, we are maintaining the Rietholzbach hydrological research station, which has been significantly expanded since 2008 (including now eddy-covariance flux measurements and comprehensive soil moisture measurements).
- ERC Consolidator Grant "DROUGHT-HEAT", 2014-2019
- EU-FP7 EUCLEIA, 2014-2016
- ESA Soil moisture CCI, 2012-2014
- EU-FP7 EMBRACE, 2011-2015
- EU-FP7 DROUGHT-R&SPI, 2011-2014
- ETH CHIRP2, 2012-1015
- SNF Sinergia Carbo-Count CH, 2012-2014
- NRP61 DROUGHT-CH, 2010-2012
- EU-FP7 CARBO-Extreme, 2009-2013
- NCCR-Climate Phase III, 2009-2012
- SwissSMEX (SNF), 2008-2011
- MAIOLICA (CCES), 2008-2012
- NCCR-Climate Phase II (SwissRe-funded research project), 2007-2009
- EU-FP6 CECILIA, 2006-2009
S.I. Seneviratne, M. Donat, A.J. Pitman, R. Knutti, and R.L. Wilby, 2016: Allowable CO2 emissions based on regional and impact-related climate targets. Nature, published online. (link; ETH News; NZZ; Tagesanzeiger; Blick; Daily Mail; Japan Times)
Guillod, B.P., B. Orlowsky, D.G. Miralles, A.J. Teuling, and S.I. Seneviratne, 2015: Reconciling spatial and temporal soil moisture effects on afternoon rainfall. Nature Communications, 6, 6443. (link; ETH Life)
Davin, E.L., S.I. Seneviratne, P. Ciais, A. Olioso, and T. Wang, 2014: Preferential cooling of hot extremes from cropland albedo management. Proc. Natl. Acad. Sci., 111(27), 9757-9761, doi:10.1073/pnas.1317323111 (link; ETH News; Spiegel; Nature News).
Greve, P., B. Orlowsky, B. Mueller, J. Sheffield, M. Reichstein, and S.I. Seneviratne, 2014: Global assessment of trends in wetting and drying over land. Nature Geoscience, 7, 716-721, doi: 10.1038/NGEO2247. (link; ETH News; Phys.org; 20 Minuten; Schweizer Bauer; Le Temps; Washington Post (online); Nature Geoscience News and Views)
Seneviratne, S.I, M. Donat, B. Mueller, and L.V. Alexander, 2014: No pause in the increase of hot temperature extremes. Nature Climate Change, 4, 161-163. (link; Reuters; The Economist; SRF2 Wissenschaftsmagazin; CBC; Climate Central)
Seneviratne, S.I., M. Wilhelm, T. Stanelle, B.J.J.M. van den Hurk, S. Hagemann, A. Berg, F. Cheruy, M.E. Higgins, A. Meier, V. Brovkin, M. Claussen, A. Ducharne, J.-L. Dufresne, K.L. Findell, J. Ghattas, D.M. Lawrence, S. Malyshev, M. Rummukainen, and B. Smith, 2013: Impact of soil moisture-climate feedbacks on CMIP5 projections: First results from the GLACE-CMIP5 experiment. Geophys. Res. Lett., 40 (19), 5212-5217 (link).
Mueller, B., and S.I. Seneviratne, 2012: Hot days induced by precipitation deficits at the global scale. Proceedings of the National Academy of Sciences, 109 (31), 12398-12403, doi: 10.1073/pnas.1204330109. (link; ETH Life article; TagesAnzeiger; Los Angeles Times; Research Highlight in Nature Geoscience)
Orlowsky, B., and S.I. Seneviratne, 2012: Global changes in extreme events: Regional and seasonal dimension. Climatic Change, 110, 669-696, doi: 10.1007/s10584-011-0122-9. (link)
Quesada, B., R. Vautard, P. Yiou, M. Hirschi, and S.I. Seneviratne, 2012: Asymmetric European summer heat predictability from wet and dry Southern winter/springs. Nature Climate Change, 2, 736-741, doi:10.1038/nclimate1536. (link)
Seneviratne, S.I., 2012: Historical drought trends revisited. Nature, 491, 338-339. (link)
Seneviratne, S.I., and R.D. Koster, 2012: A revised framework for analyzing soil moisture memory in climate data: Derivation and interpretation. J. Hydrometeorology, 13, 404-412, doi: 10.1175/JHM-D-11-044.1. (link)
Seneviratne, S.I., N. Nicholls, D. Easterling, C.M. Goodess, S. Kanae, J. Kossin, Y. Luo, J. Marengo, K. McInnes, M. Rahimi, M. Reichstein, A. Sorteberg, C. Vera, and X. Zhang, 2012: Changes in climate extremes and their impacts on the natural physical environment. In: Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation [Field, C.B., V. Barros, T.F. Stocker, D. Qin, D.J. Dokken, K.L. Ebi, M.D. Mastrandrea, K.J. Mach, G.-K. Plattner, S.K. Allen, M. Tignor, and P.M. Midgley (eds.)]. A Special Report of Working Groups I and II of the Intergovernmental Panel on Climate Change (IPCC) (link).
Davin, E.L, R. Stöckli, E.B. Jaeger, S. Levis, and S.I. Seneviratne, 2011: COSMO-CLM2: a new version of the COSMO-CLM model coupled to the Community Land Model. Climate Dynamics, 37, 1889-1907, doi: 10.1007/s00382-011-1019-z. (link)
Hirschi, M., S.I. Seneviratne, V. Alexandrov, F. Boberg, C. Boroneant, O.B. Christensen, H. Formayer, B. Orlowsky, and P. Stepanek, 2011: Observational evidence for soil-moisture impact on hot extremes in southeastern Europe. Nature Geoscience, 4, 17-21, doi:10.1038/ngeo1032. (link; News and Views; ETH Life article)
Jaeger, E.B., and S.I. Seneviratne, 2011: Impact of soil moisture-atmosphere coupling on European climate extremes and trends in a regional climate model. Climate Dynamics, 36 (9-10), 1919-1939, doi: 10.1007/s00382-010-0780-8. (link)
Mueller, B., S.I. Seneviratne, C. Jimenez, T. Corti, M. Hirschi, G. Balsamo, P. Ciais, P. Dirmeyer, J.B. Fisher, Z. Guo, M. Jung, F. Maignan, M.F. McCabe, R. Reichle, M. Reichstein, M. Rodell, J. Sheffield, A.J. Teuling, K. Wang, E.F. Wood, and Y. Zhang, 2011: Evaluation of global observations-based evapotranspiration datasets and IPCC AR4 simulations, Geophys. Res. Lett., 38, L06402, doi:10.1029/2010GL046230 (link).
Jung, M., M. Reichstein, P. Ciais, S.I. Seneviratne, J. Sheffield, M.L. Goulden, G. Bonan, A. Cescatti, J. Chen, R. de Jeu, A.J. Dolman, W. Eugster, D. Gerten, D. Gianelle, N. Gobron, J. Heinke, J. Kimball, B.E. Law, L. Montagnani, Q. Mu, B. Mueller, K. Oleson, D. Papale, A.D. Richardson, O. Roupsard, S. Running, E. Tomelleri, N. Viovy, U. Weber, C. Williams, E. Wood, S. Zaehle, K. Zhang, 2010: Recent decline in the global land evapotranspiration trend due to limited moisture supply. Nature, 467, 951-954. doi:10.1038/nature09396. (pdf;link)
Seneviratne, S.I., T. Corti, E.L. Davin, M. Hirschi, E.B. Jaeger, I. Lehner, B. Orlowsky, and A.J. Teuling, 2010: Investigating soil moisture-climate interactions in a changing climate: A review. Earth-Science Reviews, 99, 3-4, 125-161, doi:10.1016/j.earscirev.2010.02.004. (link)
Teuling, A.J., S.I. Seneviratne, R. Stöckli, M. Reichstein, E. Moors, P. Ciais, S. Luyssaert, B. van den Hurk, C. Ammann, C. Bernhofer, E. Dellwik, D. Gianelle, B. Gielen, T. Grünwald, K. Klumpp, L. Montagnani, C. Moureaux, M. Sottocornola, and G. Wohlfahrt, 2010: Contrasting response of European forest and grassland energy exchange to heatwaves. Nature Geoscience, 3, 722-727, doi:10.1038/ngeo950. (link; ETH life article)
Seneviratne, S.I., R.D. Koster, Z. Guo, P.A. Dirmeyer, E. Kowalczyk, D. Lawrence, P. Liu, C.-H. Lu, D. Mocko, K.W. Oleson, and D. Verseghy, 2006: Soil moisture memory in AGCM simulations: Analysis of Global Land-Atmosphere Coupling Experiment (GLACE) data. J. Hydrometeor., 7, 1090-1112. (link)