Variation of precipitation for the last 300 years over the middle and lower reaches of the Yellow River

摘要

The precipitation at 17 stations over the middle and lower reaches of the Yellow River is reconstructed during the period of 1736-1910, using the snow and rainfall records in the Qing Dynasty, together with the instrumental observation data of precipitation and farmland soil moisture content. The soil physics model related to rainfall infiltration and the surface water balance equation are taken as main reconstruction methodology. The field infiltration experiment by artificial rainfall is conducted to check the reliability. And the precipitation series over the middle and lower reaches of the Yellow River and its 4 sub-regions are established, going back to 1736. Analysis of the time series indicates that the abrupt change of precipitation from high to low occurs around 1915 over the middle and lower reaches of the Yellow River. During the three periods of 1791 - 1805, 1816-1830 and 1886-1895, the precipitation is markedly higher than the mean of the series. While both the periods of 1916-1945 and 1981 -2000 are characterized by less precipitation. Three periodicities of 22-25a, 3.9a and 2.7a are shown in the precipitation fluctuation over the middle and lower reaches of the Yellow River. Moreover, the periodical signal of 22-25a becomes weaker and weaker since the abrupt change of 1915 and disappears in the late 1940s, and then the periodical signal of 35-40a appears instead.