CLIGEN非降水参数在黄土高原的适应性评估

Assessment of CLIGEN non-precipitation parameters on the Loess Plateau

天气生成器(CLIGEN)可以产生以日为时间单元的天气数据,从而广泛应用于土壤侵蚀和作物生长模拟模型,其模拟结果的优劣直接影响这些模型的输出结果。利用散布黄土高原的12个标准气象站点长时间序列的气候数据评估CLIGEN模拟非降水参数(温度、太阳辐射、风速)的能力。结果表明:CLIGEN能较好的模拟日最高温度;对日最低温度与露点温度的模拟次之;模型对太阳辐射和风速的模拟较差,特别是对风速的模拟,模拟值要显著的高于实测值。CLIGEN模拟的温度日较差、第1天最高温度与第2天最低温度之差、第2天最高温度与第1天最低温度之差的均值和标准差普遍偏高,但均值的误差较小,而标准差被过高模拟;模型在产生气候数据时,没有保持逐日渐变性和连续性。CLIGEN能够较好的模拟最高温度与最低温度的季节连续性与相关性;而过高的模拟了太阳辐射的季节相关性以及温度与太阳辐射的季节互相关性;同时,模型没有模拟出各气象要素自身及其之间的逐日相关性。

Soil erosion models and crop growth simulation models are often used to assess the potential impact of climate variations. Most simulation models require daily weather data, which are frequently synthesized using stochastic daily weather generators. The objective of this study was to evaluate the ability of the CLimate GENerator （CLIGEN） to generate non-precipitation parameters, including daily temperatures, solar radiation, and wind velocity at twelve standard meteorological stations on the Loess Plateau. The results demonstrated that the CLIGEN model reproduced daily maximum temperature reasonably well. In comparison, daily minimum and dew point temperature were less well reproduced, probably because of the range check imposed in the model and used the standard deviation of minimum temperature to compute dew point. Daily solar radiation and wind velocity were less well generated than temperature; especially for wind velocity the generated data were significantly greater than the measured data. Both means and standard deviations of the same day temperature range and one day lag temperature ranges of the CLIGEN-generated data were consistently greater than those of the measured data on all sites. But the means were better reproduced than the standard deviations. Temperature tends to change in a gradual and continuous manner, but CLIGEN generated data did not reproduced this trend. Seasonal serial correlations of maximum and minimum temperatures were well reproduced, but those of solar radiation and cross correlation between temperature and solar radiation were poorly reproduced by the CLIGEN model. There were no day to day correlations for the CLIGEN-generated data, including solar radiation, maximum and minimum temperature.