Extreme temperature events in Yangtze River Basin during 1962-2011
2013, 68 (5):
Based on daily maximum and minimum temperature observed by the China Meteorological Administration at 115 meteorological stations in the Yangtze River Basin from 1962 to 2011, the methods of linear regression, factor analysis and correlation analysis are employed to analyze the temporal variability and spatial distribution of climate extremes. Sixteen indices of extreme temperature are studied. The results are as follows: (1) The occurrence of cold days, cold nights, ice days, frost days and cold spell duration days has significantly decreased by-0.84,-2.78,-0.48,-3.29 and-0.67 days/decade, respectively, while the occurrence of warm days, warm nights, summer days, tropical nights, warm spell duration days and growing season length shows statistically significant increasing trends at rates of 2.24, 2.86, 2.93, 1.80, 0.83 and 2.30 days/decade, respectively. The tendency rate of monthly minimum value of daily maximum (minimum) temperature, monthly maximum value of daily maximum (minimum) and diurnal temperature range is 0.33, 0.47, 0.16, 0.19 and-0.07 ℃/decade, respectively. (2) The magnitudes of changes in cold indices (cold nights, monthly minimum value of daily maximum, monthly minimum value of daily minimum) are obviously greater than those of warm indices (warm nights, monthly maximum value of daily maximum and monthly maximum value of daily minimum). The change ranges of night indices (warm nights and cold nights) are larger than those of day indices (warm days and cold days), indicating that the changes of day and night temperature are asymmetrical. (3) Spatially, the regionally averaged values of cold indices in the upper reaches of the Yangtze River Basin are larger than in the middle and lower reaches. However, the regionally averaged values of warm indices and growing seasons except warm spell duration indicator are larger in the middle and lower reaches than in the upper reaches. (4) The extreme temperature indices are highly correlated with each other except diurnal temperature range.
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