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利用黄河流域1963—2012年逐月气温和降水量数据,计算了各气象站点不同时间尺度的标准化降水蒸散指数(SPEI),通过对不同时间尺度SPEI与Nio 3.4区海洋表面温度距平(SSTA)的时空相关性进行分析,揭示不同时间尺度干旱对ENSO事件的响应及ENSO事件对黄河流域不同区域降水量和气温的影响。结果表明:(1)黄河流域1、3、6个月时间尺度的干旱在各时间段均有发生,12、24个月时间尺度的干旱主要发生在20世纪末和21世纪初的近20年。黄河上游和中游地区不同时间尺度的SPEI与SSTA均呈负相关关系,下游地区呈正相关关系。(2)黄河流域不同时间尺度的SPEI与SSTA相关性在空间分布上具有显著的差异性。久治站以上的黄河上游地区、中游地区的宁夏、内蒙古、陕西和山西的北部以及下游地区均呈正相关关系,其余地区呈负相关关系。全流域1、3、6、12个月和24个月时间尺度的相关性系数通过0.05显著性检验的站点占总站点数分别为14%、43%、61%、75%和44%。(3)ENSO事件强度与降水量在黄河上游地区的相关性较弱,在中游和下游地区呈显著的负相关性,强度增大时降水量下降,减弱时降水量上升。全流域ENSO事件强度与气温呈显著的正相关性,强度增大时温度有上升趋势。其中El Nio对气温有抬高的趋势,La Nia对气温有降低的趋势。
Based on the monthly temperature and precipitation data from 1963 to 2012 in the Yellow River Basin, the normalized precipitation evapotranspiration index (SPEI) of different meteorological stations at different time scales was calculated. Based on the SPEI and Nio 3.4 ocean surface temperature anomalies SSTA) to reveal the response of ENSO events at different time scales and the effects of ENSO events on precipitation and air temperature in different regions of the Yellow River. The results show that: (1) Drought in the 1,3,6 month time scales in the Yellow River Basin occurred in all time periods. The droughts in 12 and 24 month time scales occurred mainly in the late 20 years and early 21st century. There was a negative correlation between SPEI and SSTA at different timescales of the upper and middle reaches of the Yellow River and a positive correlation with the downstream areas. (2) The spatial distribution of SPEI and SSTA at different timescales of the Yellow River has significant differences. There was a positive correlation between the upper reaches of the Yellow River above Jiuzhaigou and the northern and downstream regions of Ningxia, Inner Mongolia, Shaanxi and Shanxi in the middle reaches of the region, while the rest of the regions showed a negative correlation. Correlation Coefficients at 1, 3, 6, 12 Months and 24 Months in the Whole Basin The stations that passed the 0.05 significance test accounted for 14%, 43%, 61%, 75% and 44% of the total stations, respectively. (3) The correlation between ENSO event intensity and precipitation in the upper reaches of the Yellow River is weak, and there is a significant negative correlation between the intensity of ENSO events and the lower reaches of the Yellow River. When the intensity increases, the precipitation decreases, and the precipitation decreases when the intensity decreases. The intensity of ENSO events in the whole basin showed a significant positive correlation with temperature, and the temperature tended to increase when the intensity increased. Among them, El Nio tends to increase the temperature and La Nia tends to decrease the temperature.