秦岭—淮河南北供暖格局变化及其影响因素

基于秦岭—淮河南北及其周边196个气象站点观测资料,构建实际和动态供暖指数,对中国南北过渡带供暖格局变化进行分析,并探讨冬季北极涛动（AO）异常与供暖效率的响应关系。结果表明：① 固定供暖策略下,1960-2016年秦岭—淮河南北实际供暖能耗偏高,呈现“南多北少,西低东高”的变化特征,且低纬度地区供暖需求下降信号早于高纬度;② 对比区域变暖前后,秦岭—淮河南北冬季供暖能耗1960-1990年和1990-2016年两阶段空间特征,发现“整体南高北低,北部东高西低”的格局并未发生变化,供暖南北波动界线依然维持在秦岭山脉—淮河平原中部;③ AO强弱波动与区域冬季供暖能耗具有明显的时空响应关系,是影响中国南北过渡带供暖格局变化的重要因素。当AO负相位时,除四川盆地和巫山山区之外,秦岭—淮河南北其他区域实际供暖能耗明显下降,特别是淮河平原和长江下游的过渡地带响应尤为明显,未来应该有针对性制定气候适应对策。

Spatiotemporal variability of actual heating energy efficiency and its influencing factors in areas south and north of Qinling-Huaihe Line

Using daily temperature observations from the National Meteorological Information Center of China, we analyzed the spatiotemporal variation in actual heating energy efficiency in areas south and north of the Qinling Mountains-Huaihe River (hereafter Qinling-Huanhe Line) over the period 1960-2016. The dynamic heating index, defined as the difference between fixed and dynamic heating energy consumption during the entire heating season, was used. Specifically, we analyzed the spatiotemporal response of actual heating energy efficiency to the Arctic Oscillation (AO) index, where changes in the circulation pattern bring frigid winter air to eastern China in the negative phase, resulting in increased heating energy demand. The results showed that: (1) spatial pattern of heating energy consumption in areas south and north of the Qinling-Huaihe Line was high in the eastern and southern regions, but low in the western and northern regions. The signal of decreasing heating energy demand in the lower latitudes of the region occurred earlier than in the higher latitudes. (2) On the whole, actual regional heating energy efficiency showed a decreasing trend that was corresponded with regional warming. In the north, however, the decreasing trend was weaker than in the south during the study period. This implies that residents continued to adopt a fixed-date strategy in the heating season, thus heating energy waste would increase consistently throughout the seven sub-regions, especially in the south. (3) Comparing the situation before and after climate change, i.e., 1960-1990 versus 1990-2016, we found that substantial changes were not evident in the spatial pattern of heating energy consumption in areas south and north of the Qinling-Huaihe Line. Nevertheless, there were differences in the response of temperature variations to climate change. The lower reaches of the Yangtze River, the Hanjiang River Basin, and the Wushan Mountains were some areas where heating energy waste was slowly increasing. A faster increase in heating energy waste mainly occurred in the eastern Huaihe Plain, the northwestern lower Yellow River Basin, and the Qinling-Bashan Mountains. (4) Actual heating energy efficiency had a close relationship with AO in the south-north transitional zone of China. Over the past 57 years, the AO alternated between positive and negative phases. Starting in the 1990s, the AO tended to be more of a positive phase pattern, in which higher pressure at the mid-latitudes drove warm air farther north, bringing warmer winters to the Qinling-Huaihe region, and thus decreased heating energy consumption. Spatially, the most sensitive responses of heating energy efficiency to climate change occurred in the southern Huaihe Plain and the northern regions of the lower Yangtze River Basin. In future, we should mitigate the risks of extreme climate change in sharply negative phases of the AO warrant attention, and develop policies concerning household heating in the south-north transitional zone of China.