京津冀地区气候类型划分及其动态变化

按照与现行全国气候分类或分区方案具有可比性和同时反映京津冀地区气候分类的特殊性原则,以京津冀地区56个气象站点1961—1990年和1981—2010年2个时段的累年月值和日值观测数据为基础,采用日平均气温稳定≥10℃的日数指标划分温度带,应用校正的FAO56-Penman-Monteith模型估算潜在蒸散量并计算年干燥度,采用年干燥度指标并参照地带性植被土壤分布界线划分干湿型。结果表明,研究区共划分6种气候类型。2个时段的气候类型时空变化表明,近30年来京津冀地区暖干化趋势明显,突出表现在,中温带南界明显北移,中温带范围缩小,而暖温带范围扩大。从局地尺度看,区域西北部和南部的邢台、邯郸变暖趋势最为明显,变暖趋势最小的是包括承德南部、唐山北部的燕山山地区;东部沿海地区变干趋势最为明显,其次是西北部地区,变化较小的是区域东北部和西南部。

Classification of climate types and dynamic change in Beijing-Tianjin-Hebei region

According to the national climate classification or partition scheme,and considering that the principle should reflect its specificity of the climate classification in Beijing-Tianjin-Hebei region,we calculated the yearly evapotranspiration and aridity index by FAO56-Penman-Monteith model based on the monthly observation data from 56 meteorological stations in the region of Beijing-Tianjin-Hebei during the period 1961-1991 and 1981-2010,using the days with the daily average temperature keeping steady at 10℃ or higher as an indicator to divide the temperature zone.The annual aridity index was used to divide the dry and wet type according to the zonal soil distribution.The results showed that the Beijing-Tianjin-Hebei region could be divided into six climate types.It obviously showed a decreasing trend of dry and warmth in the Beijing-Tianjin-Hebei region during the past 30 years after comparing the temporal and spatial variations in the two periods of climate classification.The southern borderline of the middle temperate zone moved northward obviously,the middle temperate zone climate diminished,and the warm temperate zone expanded.From the local scale,three areas,including the area in northwest and south of Xingtai,Handan,was getting warmer distinctly,while the smallest warming trend included Chengde,Yanshan mountain of northern Tangshan:the eastern coastal areas had an obvious dry trend,followed by the northwest area,and the smallest climate change were the northeast and the southwest areas.