近54年粤东北气候干湿状况的时空变化特征

Spatiotemporal Characteristics of 54-year Climatological Wetness Conditions in Northeastern Guangdong Province

选取1966-2019年粤东北12个国家气象观测站资料来计算湿润指数,并利用统计方法分析近54年来粤东北湿润指数的时空变化特征。结果表明:空间分布上,河源自北向南、梅州自西北向东南呈“相对湿润-相对干燥-相对湿润”的分布特征,湿润指数较高的区域主要位于地形起伏较大和大型水库、水网密集的地区。时间分布上,年湿润指数的线性变化趋势呈不显著的下降趋势;湿润指数的季节变化和地区差异明显,春季的湿润指数最高,夏季次之,秋季最低;冬春季湿润指数的大值区多位于河源市北部,低值区均位于梅州市南部;夏秋季湿润指数的大值区均位于河源市南部和梅州市东南部,低值区多位于梅州市中、北部。粤东北月湿润指数分布不均,与降水的逐月变化特征基本相一致。此外,相对湿度的显著减少和平均气温的显著升高是粤东北湿润指数减小的主导因子。

A wetness index is determined using the data from 12 national meteorological observation stations in the northeastern part of Guangdong province from 1966 to 2019 and the spatiotemporal characteristics of the index is statistically studied for the 54 years. The result is shown as follows. Spatially, it is relatively wet, dry and then wet again from the north to the south in Heyuan and from the northwest to the southeast in Meizhou. The areas with large values of the wetness index are mainly located in large topographic terrain, large-sized reservoirs and networks of rivers. Temporally, linear variations of the annual wetness index show an insignificantly decreasing trend. Seasonal variations and regional differences of the index are large and the wetness index is the highest in spring, followed by summer and then autumn. In winter and spring, areas with large values of the wetness index are mostly in the north of Heyuan and areas with small ones are all in the south of Meizhou. In summer and autumn, areas with large values of the wetness index are all in the south of Heyuan and southeast of Meizhou and areas with small ones are mostly in central and northern Meizhou. Monthly distributions of the wetness index are uneven in northeastern Guangdong, being generally consistent with the variation of monthly precipitation. In addition, significant reduction of the relative humidity and remarkable increase of mean air temperature are mainly responsible for the decrease of the wetness index in this part of the province.