1952~2018年陕西省夏季温度、降水、风速演变的城郊对比

Comparison of the Evolution of Temperature, Precipitation and Wind Speed between City and Suburb in Summer of Shaanxi Province from 1952 to 2018

城市发展过程中城区下垫面的变化对气候变化将产生明显影响。本文利用1952~2018年陕西省榆林、汉中两个站夏季月值气候资料,通过Morlet小波分析、滑动t检验等方法,对陕西城郊气温、降水、风速的变化趋势进行了对比分析。另外,针对汉中降水的时间序列进行拆分,对得到的短时间序列进行Morlet小波分析,并与拆分前时间序列进行对比。结果表明,与汉中相比,榆林气温低,降水少,风速大;两地气温、风速均呈上升趋势,但汉中降水呈下降趋势,榆林降水呈上升趋势。汉中各气象要素变化速度均比榆林明显。两地气温、降水、风速的演变时间尺度不一致。时间尺度来看,考虑边界效应,汉中夏季降水为准5年周期,榆林夏季降水没有明显的时间尺度特征。汉中夏季气温没有明显的时间尺度特征,榆林夏季气温为准2年周期、准5年周期和准8年周期。汉中夏季风速以及榆林夏季风速均没有明显的周期特征。另外,序列的拆分对于小波分析的结果是有影响的,部分年份拆分前周期不明显,拆分后则出现明显的时间尺度特征。

In the process of urban development, the underlying surface of urban areas will have a significant impact on climate change. In this paper, the monthly climatological data of Yulin and Hanzhong stations in Shaanxi Province from 1952 to 2018 were used to analyze the changing trends of air temperature, precipitation and wind speed in urban and suburban areas of Shaanxi Province through Morlet wavelet analysis and sliding t-test. In addition, according to the time series of precipitation in Hanzhong, Morlet wavelet analysis is carried out for the obtained short time series and comparison is made. The results show that compared with Hanzhong, Yulin has lower temperature, less precipitation and higher wind speed. The temperature and wind speed of the two places showed an upward trend, but the precipitation in Hanzhong showed a downward trend, while the precipitation in Yulin showed an upward trend. The change rate of meteorological elements in Hanzhong is more obvious than that in Yulin. The time scales of temperature, precipitation and wind speed are not consistent. From the perspective of time scale, considering the boundary effects, the summer precipitation in Hanzhong has a 5-year cycle, while the summer precipitation in Yulin has no obvious time scale characteristics. The summer temperature in Hanzhong has no obvious time-scale characteristics, while the summer temperature in Yulin has a 2-year cycle, a 5-year cycle and an 8-year cycle. The summer wind speed in Hanzhong and Yulin has no obvious time scale characteristics. In addition, the decomposition of sequences has an impact on the results of wavelet analysis. The period before partial years is not obvious, while the time scale features are obvious after partial years.