Jul 31, 2012

Hot days induced by precipitation deficits at the global scale

by
Brigitte Mueller, Sonia I. Seneviratne
,
Proceedings of the National Academy of Sciences
  • States hot extremes have been shown to be induced by surface moisture deficits in some regions
  • Assesses whether such a relationship holds at the global scale
  • Finds that wide areas of the world display a strong relationship between the number of hot days in the regions’ hottest month and preceding precipitation deficits
  • Finds the occurrence probability of an above-average number of hot days is over 70% after precipitation deficits in most parts of South America as well as the Iberian Peninsula and Eastern Australia, and over 60% in most of North America and Eastern Europe, while it is below 30–40% after wet conditions in these regions
  • Shows that the impact of precipitation deficits on the number of hot days is asymmetric, i.e. extreme high numbers of hot days are most strongly influenced
  • Findings suggest that effects of soil moisture-temperature coupling are geographically more widespread than commonly assumed