Character of Precipitation in Ningxia and Its Response to ENSO
According to the monthly precipitation data during 1959 -2001, we find the drought trend was obvious from the 1960s to the 1980s, and more precipitation was observed in the 1990s than in the 1980s. Power spectrum analysis shows that there exist three obviously simultaneous periods between precipitation in Ningxia and ENSO: 14 years, 3.75 years, approximately 2 years and 1.5 years. Precipitation in Ningxia responds quicker to La Nina than to El Nino, the lag time of the former is 1 -2 months while the latter is 2 -4 months. The impact that ENSO imposes on the seasonal precipitation varies tremendously. Four months later after the El Nino event, the precipitation decreases in spring, summer and autumn except a winter's increase. One month later after the La Nina event, the precipitation experienced a large increase in summer, autumn and winter except a spring's decrease. During the period of El Nino event the precipitation in Ningxia shows a 28mm decrement, whose proportion to the perennial year is 10°. However, during the period of El Nino event the precipitation in Ningxia has a 24-mm increment, which accounts for 9%.
NETL
NSTL
万方数据
维普
