Statistical downscaling for climate change projections in the Mediterranean region: methods and results

Abstract

Besides dynamical downscaling by regional climate models, statistical downscaling (SD) is a major tool to derive climate change projections on regional or even local scales. For the Mediterranean area, an increasing number of downscaling studies based on different statistical techniques have been published in the last two decades with a broad range of sometimes differing results relating to different variables and regional domains. This paper gives a short review of these Mediterranean downscaling studies mainly considering the following two aspects: (1) what kind of progress has been realized in this field since the early 1990s? The review addresses the inclusion of extremes in downscaling assessments, the development of probabilistic approaches, the extension of predictor sets, the use of ensembles for both dynamical model simulations and statistical model assessments, the consideration of nonstationarities in the predictor-predictand relationships, and some advances related to synoptic downscaling. (2) What are the main regional climate change signals in the Mediterranean area, considering agreed and controversial points also with respect to dynamical models? Best accordance among future projections can be found in seasonal temperatures with lower rates of warming in winter and spring, and, in most cases, higher ones in summer and autumn. Different results are obtained for the intra-annual range of extreme temperatures, but high-temperature conditions are generally expected to increase. Regarding seasonal precipitation, predominant reductions are indicated for spring, summer, and autumn. For winter, however, projections are distinctly different (GCMs: rainfall decrease; RCMs: increase only in the northernmost parts of the Mediterranean region; SD: widespread increases in the northern and western parts in several studies). Different results are obtained for rainfall extremes, but the entire precipitation distribution tends to shift towards higher and lower values. Apart from some sub-regional deviations, there is a predominant increase in future dry period durations. For near-surface winds, only a few studies are available, and they project some decline mainly for the winter season.

The climate of the Mediterranean region: research progress and climate change impacts

“…For the Mediterranean area, an increasing number of downscaling studies based on different statistical techniques have been published in the last two decades with a broad range of sometimes differing results relating to different variables and regional domains. Jacobeit et al (2014) give a short review of the statistical downscaling studies in the Mediterranean region, describing their progress since the early 1990s, the main regional climate change signals, agreed and controversial points. Best accordance among future projections can be found in seasonal temperatures with lower rates of warming in winter and spring and higher rates in summer and autumn.…”

Variability of seasonal and annual precipitation in Slovenia and its correlation with large-scale atmospheric circulation

“…Significant progress has been made on climate projections for the MR [1]. Future projections regarding seasonal precipitation show predominant reductions for spring, summer and autumn, however projections for winter are distinctly different [2]. Precipitation is projected to decrease in all parts and all seasons (the most significant percent change occurs in summer) except for the northernmost parts in winter [3].…”

An Innovative Method to Evaluate the Impact of Temperature on Iodosulfuron-Methyl Selectivity to Oat Crop

“…At least two practical applications can be foreseen from this work. First, the predicted planet warming due to anthropogenic climate change (Jacobeit et al, 2014) may be beneficial, at least in part, to the oat production because herbicides from new mechanisms of action can became available to selective weed control on the crop. Second, current trends to expand the cultivation of the oat crop to warmer parts of the world (central Brazil and India) suggest increased tolerance to iodosulfuron-methyl with high temperatures would allow additional opportunity for weed management on this crop.…”