Recent decrease in summer precipitation over the Iberian Peninsula closely links to reduction in local moisture recycling

[摘要] The inherently dry summer climate of the Iberian Peninsula (IP) is undergoing drought exacerbated by more intense warming and reducedprecipitation. Although many studies have studied changes in summer climatefactors, it is still unclear how the changes in moisture contribution fromthe sources lead to the decrease in summer precipitation. This studyinvestigates the differences in the IP precipitationshed from 1980 to 1997and 1998 to 2019 using the Water Accounting Model-2layers with ERA5 data, and assesses the role of local moisture recycling and external moisture inreducing summer precipitation. Our findings indicate that the moisturecontributions from the local IP, and from the west and the east of theprecipitationshed, contributed 1.7, 3.6 and 1.1 mm per month less precipitation after 1997 than before 1997, accounting for 26 %, 57 % and 17 % of the main source supply reduction, respectively. The significant downward trend of the IP local moisture recycling closely links to the disappearance of the wet years after 1997 as well as the decrease in local contribution in the dry years. Moreover, the feedback between the weakened local moisture recycling and the drier land surface can exacerbate the local moisture scarcity and summer drought.

[学科分类] 妇产科学