Spatiotemporal variation of the major meteorological elements in an agricultural region: A case study of Linyi City, Northern China

Evaporation is a key element of the water and energy cycle and is essential in determining the spatial and temporal variations of meteorological elements. In particular, evaporation is crucial for thoroughly understanding the climate variations of a region. In this study, we discussed evaporation, precipitation, and temperature by adopting Linyi City in Shandong Province, China, which is an important agricultural region, as a research case. Linear regression analysis, the empirical orthogonal decomposition function, and the Morlet wavelet function were used to reveal the trends, spatiotemporal modes, and multi-time scale characteristics of the three climate factors and provide a theoretical basis for the efficient use of climate resources in the future development of regional agriculture. Results showed that the precipitation (2.09 mm/a) and temperature (0.04 ℃/a) in Linyi City exhibited a synchronous growth trend. Conversely, evaporation (−6.47 mm/a) showed a decreasing trend and the evaporation paradox because of the considerable decrease in evaporation energy. Regional development of water-consuming agriculture in consideration of global warming is a key point for improving water use efficiency in Linyi City. In terms of spatial distribution, precipitation was dominated by the first mode wherein low precipitation was observed at the early stage, and high precipitation occurred at the late stage. The first mode was supplemented by the second mode wherein an inverse phase change occurred in the southeast-northwest direction. Large interannual fluctuations were observed only in Yinan County. Temperature exhibited a pattern of warming change with high homogeneity. Evaporation demonstrated obvious heterogeneity and was dominated by two major modes, and the difference in evaporation between Junan County and the other regions of Linyi City was large. Therefore, the local regional climate changes in Yinan and Junan should be given attention. All three meteorological elements showed interannual and interdecadal variations in the short (5 a), medium (16 a), and long (25 a) terms, with precipitation, temperature, and evaporation dominated by 16 a, 24 a, and 31 a, respectively. In the short-term future, the regional precipitation and temperature in Linyi will experience decrements that are above the multiyear average, and evaporation will increase to above the multiyear average. Given the changing trends of precipitation, temperature, and evaporation, urgent requirements for the regional development of efficient water-saving irrigation and the promotion of digital agriculture should be proposed.