A high-quality monthly pan evaporation dataset for Australia

作者:Jovanovic Branislava*; Jones David A; Collins Dean
来源:Climatic Change, 2008, 87(3-4): 517-535.
DOI:10.1007/s10584-007-9324-6

摘要

A high-quality monthly pan evaporation dataset of 60 stations has been developed for monitoring long-term pan evaporation trends over Australia. The quality control process involved examination of historical station metadata together with an objective test comparing candidate series with neighboring stations. Identified points of discontinuity were located, including installations of bird guards, site relocations and changes in exposure. Appropriate inhomogeneity adjustments have been applied using established methods to produce the first homogeneous pan evaporation dataset for Australia. Analysis of these data reveals that Australian annual mean pan-evaporation shows large interannual variability with no trend over the 1970-2005 period. Previous studies using unadjusted data have shown a decline in pan evaporation, highlighting the importance of checking data for homogeneity before drawing conclusions about long-term trends. A strong inverse correlation is evident between all-Australian means of pan evaporation and rainfall, while a moderate positive correlation is found between pan evaporation and mean temperature. The positive correlations between mean temperature and pan evaporation that exist on the interannual time scales are not reflected in the long-term trends, highlighting that the mechanisms that are responsible for variations on the short and longer time scales are different. This result cautions against the expectation that large changes in potential evaporation are a natural consequence of global warming.