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为了深入分析气温对长江上游年径流的影响和解释青藏高原冰川融水再冻结现象的物理机制,采用对位置、尺度、形状的广义可加模型(简称GAMLSS)建立控制因素降水、气温、ATD与年径流量之间的关系。在GAMLSS框架下,气温影响因子可以用两种形式表示,一种是直接采用气温,另一种是采取ATD指数(累积气温亏损值)。通过比较不同解释变量组合下的GAMLSS模型,进而研究气温对长江上游巴塘站1960~2012年的年径流影响。结果表明:基于ATD的回归模型,在年径流序列服从对数正态分布假设的条件下拟合效果最优。与气温值相比,ATD指数能更有效地解释长江上游径流变化的特征和冰川产流的物理机制。研究成果对长江上游年径流预报、高原气候下的产流特征分析具有理论意义。
In order to further analyze the effect of temperature on the annual runoff in the upper reaches of the Yangtze River and to explain the physical mechanism of glacial melt re-freezing on the Qinghai-Tibet Plateau, the generalized additive model (GAMLSS) of position, scale and shape is used to establish the control factors of precipitation, temperature, The relationship between annual runoff. Under the framework of GAMLSS, the temperature impact factor can be expressed in two forms, one is the direct use of temperature and the other is the ATD index (cumulative temperature loss). By comparing the GAMLSS models under different explanatory variables, the effect of temperature on the annual runoff of Batang station in the upper reaches of the Yangtze River from 1960 to 2012 was studied. The results show that the regression model based on ATD has the best fitting effect under the assumption that the annual runoff sequence obeys the assumption of lognormal distribution. Compared with the temperature, the ATD index can explain the characteristics of runoff changes and the physical mechanism of glacier runoff in the upper reaches of the Yangtze River more effectively. The research results have theoretical significance for the prediction of annual runoff in the upper reaches of the Yangtze River and the characteristics of runoff in the plateau climate.