The contribution of reduction in evaporative cooling to higher surface air temperatures during drought

• Published in: Geophysical research letters Vol. 41; no. 22; pp. 7891 - 7897
• Main Authors: Yin, Dongqin, Roderick, Michael L., Leech, Guy, Sun, Fubao, Huang, Yuefei
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 28.11.2014; John Wiley & Sons, Inc
• Subjects: Air temperature; Approximation; Aridity; Atmospheric precipitations; Brazil; Carbon dioxide; Climatic data; Cooling; Drought; Droughts; Evaporation; Evaporative cooling; Fluxes; Global warming; High temperature; Mathematical analysis; Meteorology; Precipitation; Reduction; Signatures; Surface temperature; Temperature; Temperature effects; Brazil; Australia; United States > US
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2014GL062039

Higher temperatures are usually reported during meteorological drought and there are two prevailing interpretations for this observation. The first is that the increase in temperature (T) causes an increase in evaporation (E) that dries the environment. The second states that the decline in precipitation (P) during drought reduces the available water thereby decreasing E, and in turn the consequent reduction in evaporative cooling causes higher T. To test which of these interpretations is correct, we use climatic data (T, P) and a recently released database (CERES) that includes incoming and outgoing shortwave and longwave surface radiative fluxes to study meteorological drought at four sites (parts of Australia, US, and Brazil), using the Budyko approximation to calculate E. The results support the second interpretation at arid sites. The analysis also showed that increases in T due to drought have a different radiative signature from increases in T due to elevated CO2. Key Points Temperature increases during drought but the interpretation is disputedTemperature increase during drought is partly due to surface feedbacksRadiative signature of drought differs from a direct global warming signature