Characteristic Analysis of the Climatic Revolution in the Yellow River Extreme Temperature Index
Chinese Journal of Agrometeorology
2015, 36 (05):
In this paper, the spatiotemporal variation of extreme temperature events were investigated based on the daily maximum and minimum temperature data observed by 59 meteorological stations for the period 1963-2013 in the Yellow River Basin(YRB), with the help of liner regression, Mann-Kendall test, wavelet analysis, principal component analysis and correlation analysis. The results showed that, (1)cool days, cool nights, ice days, frost days and cold speel duration days displayed significant negative trend at rates of 1.06, 1.93, 2.40, 3.36 and1.12d·10y-1, respectively(P＜0.001), while warm days, warm nights, summer days, tropical nights, warm speel duration days and growing season length exhibited significant positive trend at rates of 1.56, 2.22, 2.66, 1.56, 1.48 and 3.47d·10y-1 (P＜0.001), respectively. Furthermore, the trends for annual minimum value of daily minimum (maximum) temperature, annual maximum value of daily minimum (maximum) and diurnal temperature range were 0.25(0.4), 0.18(0.27) and -0.09℃·10y-1 (P＜0.05), respectively. (2)The six sub-region’s extreme temperature indices remained same variation tendency, while the extreme temperature events of north-central Ningxia and south–central Inner Mongolia were more significant. (3)The change range of night indices(warm nights, cold night) were larger than those day indices (warm days, cold days), the range of variation in cold indices (annual minimum value of daily minimum/maximum) were smaller than warm indices (annual maximum value of daily minimum/maximum). (4)The upper-middle of Yellow River were more sensitive than downstream for the extreme temperatures change. (5)All of 16 indices had short cycles of 3 and 7 years, and had long cycles of 26 years, while warm/cold spell duration days, diurnal temperature range and growing season length also had another cycle of 16 years. (6)Besides, annual minimum value of daily minimum, diurnal temperature range and cold spell duration days, the time points of abrupt change for others were concentrated in 1990s.
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