Eighty years of meteorological observations at Wageningen, the Netherlands: Precipitation and evapotranspiration

摘要

Annual and seasonal characteristics of precipitation and evapotranspiration were analysed of an 80-year data record (1928-2008) at Wageningen (the Netherlands). The precipitation series shows a mean annual rainfall of 765 ± 130 mm with a relatively high interannual variability [coefficient of variation (CV) = 17.0%]. Both the annual and seasonal rainfall trends show a small but statistically insignificant increase. Potential evapotranspiration was estimated by Makkink's formula, using observations of incoming solar radiation and air temperature as inputs. This provides a mean evapotranspiration of (525 ± 50) mm annum~(-1) with a relatively low interannual variability (CV = 9.5%). The annual and seasonal trends appear to be statistically significant, except for the summer season. In addition, since 1992, actual evapotranspiration is measured by the eddy-covariance technique and these results were found to be highly correlated with the potential evapotranspiration (E_(act) ≈ 0.75E_(pot)). A comparison is made with a class A evaporation pan operating between 1984 and 1989.