BCC/RCG-WG天气发生器非降水变量模拟参数气候变化特征

利用中国699 个气象站点1951-2007 年的逐日最高气温、最低气温和日照时数资料,分1951-1978 年和1979-2007 年两个时段分析了气候变化对BCC/RCG-WG天气发生器中我国各地逐日非降水变量模拟参数的影响.结果表明,最高气温、最低气温和日照时数三个变量平均值傅立叶级数展开式的年平均值和基波振幅较标准差傅立叶级数展开式的年平均值和基波振幅的变化幅度明显偏大,而平均值傅立叶级数展开式的基波位相变化幅度较标准差的基波位相变化幅度明显偏小;三个变量当天以及后延一天之间的相关系数的绝对变化较小.说明在气候变化背景下,最高气温等三个非降水变量的年平均值和年内变幅有明显的变化,而三个变量年际间的变异、峰值出现时间以及各变量之间的相关性变化较小.

Impacts of climate changes on parameters of weather generator BCC/RCG-WG for daily non-precipitation variables simulation in China

Parameters of daily non-precipitation variables including maximum temperature, minimum temperature and sunshine hours simulation at 699 stations in China of weather generator BCC/RCG-WG are estimated using historical daily records from 1951 to 1978 and from 1979 to 2007 respectively. The two sets of parameters for the two periods are compared to explore the impact of climate change on these parameters. The results show that the parameters of non-precipitation variables have experienced different changes, while the annual means and the amplitudes of the seasonal cycle show a significant change, and the interannual variability, seasonal timing and temporal correlations for each variable remain practically unchanged. This indicates that climate change in China in terms of these variables are mainly reflected in changes in the means and in the strength of the seasonal cycles. The changed parameters have implications for the stationarity assumption implied in the parameter estimation and use of the weather generator.