关键词: 极端气温, 京津冀地区, 玉米产量, 相关性

Abstract:

 Extreme climate change, which can cause agricultural problems, has become a global hot topic. In recent decades, the Beijing-Tianjin-Hebei region has experienced several extreme climate events that have had a significant impact on grain yields. This study evaluted the impact of climate change on grain yields in the Beijing-Tianjin-Hebei region from 1980 to 2020 using meteorological data and maize yield per unit area data at eight sites and selected 25 national meteorological stations. Four types of statistical methods were selected, including linear regression, inverse distance weighting interpolation, M-K test, and Pearson correlation, to analyze the characteristics of climate change (maximum, minimum and average temperature, and growing degree days) and its impacts on maize yields. The results revealed: (1) the growing degree days (GDD) and temperature indices such as extreme maximum temperature (TXx) and high temperature days (Htd) exhibited an upward trend over time, with increase rates of 58.31℃·d·10y⁻¹, 0.39℃·10y⁻¹ and 0.96d·10y⁻¹, respectively. However, the low temperature indices (extreme minimum temperature, low temperature days) tended to decrease with decrease rates of 0.28℃·10y⁻¹ and 2.8d·10y⁻¹, respectively. Mutation analysis indicated a higher mutation rate for high temperature indices compared to low temperature indices, indicating a clear warming trend in the Beijing-Tianjin-Hebei region from 1980 to 2020. (2) The spatial distribution of extreme temperature index terms was different. High value of high temperature indices were primarily concentrated in economically developed cities such as Beijing and Tianjin, while low temperature indices were mainly concentrated in the northern (Zhangbei) and southwestern (Xingtai) areas. (3) The grain yield presented a fluctuate increase, with climate yield of maize fluctuating greatly (−1179 to 831kg·ha⁻¹). There were three climatic bumper years (2004, 2005 and 2006) and two lean years (1999, 2000) from 1990 to 2020 in the study area. Correlation analysis indicated that GDD、TXx、Htd were the primary response indices for grain yields in the Beijing-Tianjin-Hebei region, it can be seen that when TXx≥36℃, Htd≥4d, the climatic yield of maize decreases gradually. 

Key words: Extreme temperature, Beijing-Tianjin-Hebei region, Maize yield, Correlation