Objectives of the StaRMIP project

The main aim of this project is to study the uncertainties of statistical regionalization (or downscaling) of precipitation (PR) and temperature (T) at relatively high resolution (HR, here 0.44°x0.44°) and their hydrological impacts in the Mediterranean region.

Indeed, this region has geographical and environmental specificities (e.g., mountPppppins, ocean and sea, high density of population) making necessary but particularly complex the downscaling of precipitation and its HR modeling. Moreover, this region has been identified as a “hot-spot” by IPCC (2007) for future climate changes. Indeed, while the signs of the trends seem defined, strong uncertainties remain in the intensity, the patterns and distributions of those changes.

In this context, the StaRMIP project aims at intercomparing the whole set of the main statistical approaches for the regionalization of PR ant T (still too often considered as “black boxes”) in their uses and conceptual differences. Ensembles of HR statistically downscaled PR and T will be generated and the simulated fields will be integrated into hydrological models in order to evaluate their quality in space and time via sensitivity analyses. Based on those evaluations, a new statistical downscaling model will be developed to fill in the most important weaknesses and gaps of the state-of-the-art models. The HR projections for future, plugged into the hydrological models, will also serve to forecast future water availability under the constraint of various climatic projections.

Hence, this project will provide:
  • Ensembles of control (CTRL, 1989-2010) and future (2021-2050 and 2051-2080) HR statistical simulations of precipitation and temperature
  • Guidelines to their relevant uses and interpretations;
  • Indicators quantifying the quality (in space, time and extreme representation) of the HR simulations;
  • An as-generic-as-possible statistical downscaling model improving the state-of-the art models;
  • Retrospective and prospective hydrological scenarios of water availability on several Mediterranean catchments; ands
  • Uncertainty assessment of the climate and hydrological simulations, using well dedicated statistical models.
The proposed intercomparisons and studies will also be extended to a part of the datasets of the dynamical simulations available from the Med-CORDEX project. The results brought by the different studies will provide theoretical and practical “guidelines” for the applications of the statistical regionalization approaches, whose relative strengths, weaknesses, and potential improvements are still not well known while they are more and more applied.

Moreover, the statistical downscaling algorithms, the high-resolution simulations, as well as the evaluation techniques of those, will be freely provided to the scientific community.