Regional Climate Information

Downscaling of climate scenarios to regional/local level and support for climate impacts and adaption work.

Background

Information about possible future climate change under global warming is becoming an integral part of developing suitable adaptation and mitigation strategies at global, national, regional and local levels. The use of downscaling techniques (regional climate models and statistical methods) as a source of high-resolution regional climate information has been well established and recognised with a remarkable progress within the Coordinated Regional climate Downscaling Experiment (CORDEX). During the recent years a large number of downscaled climate change scenarios for different regions worldwide were generated and made openly available.

Focus

Even though a large volume of regional climate data is available, still there are many gaps in our understanding of regional climate; additionally  data does not necessary mean information. Now the main focus is on how to translate this regional climate data to regional climate information relevant and usable for decision and policy making. To advance such translation it is necessary to fill the gaps in our understanding of regional climate and address scientific questions not fully explored at moment.

Research questions

  • What is the contribution to regional climate from local (e.g., snow, soil moisture, soil moisture-precipitation feedback) and global (e.g. teleconnections) drivers in different regions?
  • What is the source of contradicting messages across different climate data? What kind of local processes are involved in these contradicting messages?
  • What level of uncertainties does bias adjustment (correction) introduce to regional climate information?
  • How to provide an integral measure of uncertainty for the entire downscaling chain (global climate models / downscaling / bias adjustment / regional impact studies)?
  • What is the spatial and temporal scale dependency of uncertainties in regional climate information?
  • Can smaller subsets of climate simulations from a grand ensemble be representative and how to select such subsets?

Tools

To address these scientific challenges a number of new and novel approaches are being applied, namely:

  • advanced statistical analysis in order to clarify contribution of large-scale and local processes to regional climate  and the added value of downscaling  
  • new targeted downscaling experiments
  • different bias adjustment methods
  • different methodologies for selection of reduced ensembles of climate simulations.

All the above steps aim to provide ‘transformed’ scale-relevant climate information necessary for impact studies and are ongoing in close cooperation with international partners and with other groups at SMHI. Such activities are inline with the Global Framework for Climate Services (GFCS) coordinated by WMO and will help in establishing climate services infrastructure.

Recent publications

  • Nikulin G. and 20 Co-Authors, Dynamical and statistical downscaling of a global seasonal hindcast in eastern Africa, submitted to Climate Services (EUPORIAS special issue), submitted January 2017.
  • Leedale, J., Tompkins, A. M., Caminade C., Jones, A. E., Nikulin, G. and Morse A. P. 2016. Projecting malaria hazard from climate change in eastern Africa using large ensembles to estimate uncertainty, Geospatial Health, 11(s1):393, doi:10.4081/gh.2016.393
  • Endris, H. S., C. Lennard, B. Hewitson, A. Dosio, G. Nikulin and H. J. Panitz, 2015: Teleconnection responses in multi-GCM driven CORDEX RCMs over Eastern Africa. Climate Dynamics, doi: 10.10007/s00382-015-2734-7
  • McCreesh N., Nikulin, G., and Booth M., 2015. Predicting the effects of climate change on Schistosoma mansoni transmission in eastern Africa. Parasites & Vectors, 8:4,doi:10.1186/s13071-014-0617-0
  • Nikulin G., Jones, C. , Giorgi, F., Asrar, G., Büchner, M., Cerezo-Mota, R., Christensen, O. B., Déqué, M., Fernandez, J., Haensler, van Meijgaard, E., Samuelsson P., Sylla M. B., and Sushama L., 2013.  Precipitation Climatology in An Ensemble of CORDEX-Africa Regional Climate Simulations, J. Climate, 25, 6057–6078. doi: 10.1175/JCLI-D-11-00375.1
  • Pryor, S. C., G. Nikulin, and C. Jones, 2012. Influence of spatial resolution on regional climate model derived wind climates, J. Geophys. Res., 117, D03117, doi:10.1029/2011JD016822
Fig1_RCI_RC
Figure 1. An example how two RCM ensembles project contradicting changes in July-September rainfall over West Africa. The projections generated by two regional climate models (RCA4 and CCLM4-8-17) at about 50km resolution driven by the same four global climate models (CNRM-CM5, EC-EARTH, HadGEM2-ES and MPI ESM-LR) under RCP8.5 scenario.