Abstract:

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.

Key words: climate change, heating energy efficiency, spatiotemporal analysis, Arctic oscillation, Qinling-Huaihe region