Increased summer electric power demand in Beijing driven by preceding spring tropical North Atlantic warming

Abstract

By using electric power data, observational station temperature data in Beijing, CN05.1 temperature data, ERA5 atmospheric reanalysis data, and ERSST.v3b sea surface temperature (SST) data, it is found that summer (July–August) electric power demand in Beijing is remarkably positively correlated with the previous spring (March–April) tropical North Atlantic (TNA) SST anomaly (SSTA). The possible physical mechanism of the TNA SSTA affecting summer electric power in Beijing is also revealed. When a positive SSTA occurs in the TNA during spring, anomalous easterlies prevail over the tropical central Pacific, which can persist to the following summer. Trade winds are thus enhanced over the northern Pacific, which favors a strengthening of upwelling cold water in the tropical central-eastern Pacific. As a result, a negative SSTA appears in the central-eastern Pacific in summer, which means a La Niña event is triggered by the previous TNA SSTA through the Bjerknes feedback. During the La Niña event, an anomalous anticyclonic circulation occupies the northwestern Pacific. The southerly anomalies at the western edge of this anomalous anticyclone strengthen the transportation of warm and humid airflow from the low latitudes to North China, where Beijing is located, causing higher summer temperatures and increased electricity usage for air conditioning, and vice versa. The results of this study might provide a new scientific basis and clues for the seasonal prediction of summer electric power demand in Beijing.摘要本文利用北京市电力负荷资料, 北京市站点观测温度资料, CN05.1温度资料, ERA5大气再分析资料及ERSST v3b海表温度资料, 发现3–4月副热带北大西洋海温异常和北京市夏季电力呈很好的正相关关系, 并揭示了副热带北大西洋海温异常影响北京市夏季电力的可能物理机制. 春季副热带北大西洋海温异常偏暖, 热带中太平洋出现东风异常并持续至夏季, 太平洋信风增强, 热带中东太平洋冷水上翻增强, 通过Bjerkness正反馈机制激发了La Niña事件. La Niña事件时, 西北太平洋反气旋环流异常, 将低纬度暖湿气流输送至北京地区, 引起北京市夏季温度增高, 电力负荷需求增加. 反之亦然. 研究结果可为北京市夏季电力负荷需求的季节预测提供新的科学依据和线索.