Spatiotemporal variation of main meterological elements in agricultural region: A case study

Abstract

Despite the fact that evaporation is a key element of water and energy cycle, little attention has been paid to it. Thus, discovering the spatial and temporal variations of meteorological elements in Linyi Agricultural City of Shandong Province in the past 50 years is crucial. This study discussed evaporation, precipitation, and temperature. Linear regression analysis, empirical orthogonal decomposition function, and Morlet wavelet function were used to reveal the trend, temporal and spatial modes, and multi-time scale characteristics, providing a theoretical reference basis for the efficient use of climate resources for the future development of regional agriculture. Results showed that the precipitation (2.09 mm/a) and temperature (0.04 °C/a) in Linyi had a synchronous growth trend; conversely, the evaporation (−6.47 mm/a) showed a decreasing trend of “evaporation paradox” due to the significant decrease of evaporation energy. Under the development trend of global warming and high water-consuming agriculture, improving regional water use efficiency is a key point. In terms of spatial distribution, precipitation was dominated by the first mode, which showed little in the early stage while more in the later stage, supplemented by the second mode with an inverse phase change in the southeast–northwest direction. A large inter-annual fluctuations was only found in Yinan County. The temperature showed a pattern of warming change with outstanding homogeneity. The evaporation exhibited an obvious heterogeneity, which was dominated by two main modes with a great difference between Junan County and other regions in Linyi city. Therefore, local regional climate changes in Yinan and Junan should be given attention. All three meteorological elements had inter-annual and interdecadal variations in the short term (5 a), medium term (16 a), and long term (25 a), dominated by precipitation (16 a), mean annual temperature (24 a), and annual evapotranspiration (31 a). In the short-term future, the regional precipitation and temperature in Linyi would experience decreasing changes above the multi-year average, and evaporation would show increasing changes above the multi-year average. Given the changing trends of precipitation, temperature, and evaporation, urgent requirements for regional development of efficient water-saving irrigation and promotion of digital agriculture should be proposed.