Multi-time Scales Change Characteristics and Relationship of Meteorological Variables in the Upper and Middle Regions of the Huaihe River Basin in Recent 55 Years
In order to understand the multi-timescales change characteristics and relations of regional meteorological variables (namely the monthly precipitation, temperature and sunshine hours) in the upper and middle regions of the Huaihe River Basin, data of 19 meteorological stations from 1960 to 2014, were analyzed by using the methods of climate tendency rate, Mann-Kendall test, morlet wavelet analysis and correlation coefficient. The results showed that: 1) The linear trends of precipitation in annual and four seasons were not significant. For temperature, its linear trend was not significant in summer, but in annual and other three seasons, a significant trend of getting warm was shown. For sunshine hours, its linear trend was not significant in spring, but in annual and other three seasons, a significant trend of getting short was shown; 2) Precipitation, temperature and sunshine hours in annual and four seasons were characterized by alternatively wet and dry, cold and warm, short and long variations for multiple time scales. Differences between the main period scales and their mean change cycles for the three meteorological variables in annual and four seasons were different, some were close while the others had large gap. The main period scales ranged from 2 to 10 years. 3) Multiple correlation coefficient of temperature was smaller than that of precipitation and sunshine hours in annual and four seasons. Multiple correlation coefficient of winter temperature was the smallest, while for temperature in the annual and other seasons, precipitation and sunshine hours, the multiple correlation coefficient were bigger. The absolute value of partial correlation coefficient between precipitation and sunshine hours were the biggest in annual and all seasons. Precipitation and sunshine hours, temperature and precipitation both had inverse relationship in most cases, while, winter temperature and sunshine hours showed the phase change on the main period scales of 28 a. The regional hydrothermal resources distribution can be better understood by the analysis in this article, which could also provide reference for the formulation of agricultural cropping system, water resources planning and flood and drought management.