Precipitation–temperature relationships over Europe in CORDEX regional climate models

• Published in: International journal of climatology Vol. 42; no. 9; pp. 4868 - 4880
• Main Authors: Lhotka, Ondřej, Kyselý, Jan
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2022; Wiley Subscription Services, Inc
• Subjects: Anomalies; Climate change; Climate change scenarios; Climate models; Cloud cover; CORDEX; Correlation; Europe; Ocean bottom seismometers; Precipitation; Radiation; Regional climate models; Regional climates; Relative humidity; Short wave radiation; Standardized precipitation index; Summer; temperature; Temperature anomalies; Winter; Europe
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.7508

We studied spatial and temporal patterns of precipitation–temperature (P–T) relationships through correlations between monthly standardized precipitation index (SPI) and monthly temperature anomalies in individual climatic seasons over Europe. In the observed data (represented by E‐OBS), positive correlations (wet–warm/dry–cold relationships) prevail during winter over most of Europe, while negative values (dry–warm/wet–cold) are dominant in summer. In the next step, an ensemble of seven regional climate models (RCMs) from the CORDEX project driven by the ERA‐Interim reanalysis were examined as to their reproduction of the regional patterns of the P–T correlations. In winter, the RCMs yielded overly strong positive P–T correlations over northern Europe, while the correlations were too weak in the south compared to observed data. During summer, the biases were generally larger; the RCMs were able to capture the overall negative P–T correlations but these tended to be too weak over northern Europe. This deficiency was found to be linked to simulated differences in shortwave radiation (a proxy for cloud cover) between dry and wet months. In western, central, and southeastern Europe, by contrast, most RCMs yielded too strong negative correlations in summer, and overly large decreases of relative humidity during dry months probably contributed to these errors. The results pointed up issues that should be addressed as the reported RCMs' deficiencies may lower credibility of projected compound dry–hot events in climate change scenarios. We evaluated the capability of CORDEX regional climate models (RCMs) driven by the ERA‐Interim reanalysis to reproduce precipitation–temperature (P–T) relationships over Europe. In summer, the majority of the RCMs yielded too weak negative correlations over northern Europe and the Iberian Peninsula, while the strength of the negative correlations was overestimated in western, central, and southeastern Europe. These errors were associated with simulated characteristics of shortwave radiation and relative humidity.