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Seasonal changes in East Asian monsoon-westerly circulation modulated by the snow-darkening effect of mineral dust
Atmospheric Research ( IF 5.5 ) Pub Date : 2022-08-08 , DOI: 10.1016/j.atmosres.2022.106383
Liu Yang, Zhengguo Shi, Xiaoning Xie, Xinzhou Li, Xiaodong Liu, Zhisheng An

The snow-darkening forcing of dust (SFD) is known to occur when dust-covered snow reduces surface albedo and absorbs more radiation, which causes snowmelt and surface warming. To date, few studies have focused on how SFD affects atmospheric circulation. In this study, we used a climate model to evaluate the influence of the SFD on seasonal changes in coupled monsoon westerlies over East Asia. The results indicate that the SFD causes anomalies in temperature, precipitation, and atmospheric circulation over East Asia. In December and January (DJ), the temperature increase over the Tibetan Plateau is significant, and the anomalous anticyclonic circulation causes a weakening of the westerly circulation during this period. In February, March, and April (FMA), the SFD causes an increase in temperature over the plateau and its eastern flank and widespread anomalous cooling to the north, which can be attributed to diabatic cooling of the upper atmosphere. These changes in thermal conditions lead to enhanced westerly winds and weakened East Asian winter monsoons during FMA. The enhanced westerly winds bring more precipitation to the East Asian continent. In May, June, and July (MJJ), only the Tibetan Plateau is significantly warmed in East Asia. At this time, the westerly circulation weakens, and the East Asian summer monsoon strengthens. The low-level atmospheric circulation shows anomalous westerly winds over South Asia. The anomalous westerly winds from Central Asia bring dry air and result in reduced precipitation over India.



中文翻译:

受矿物尘埃变暗效应调节的东亚季风-西风环流季节变化

众所周知,当被尘埃覆盖的雪降低地表反照率并吸收更多辐射时,就会发生沙尘的积雪强迫(SFD),这会导致融雪和地表变暖。迄今为止,很少有研究关注SFD如何影响大气环流。在这项研究中,我们使用气候模型来评估 SFD 对东亚耦合季风西风带季节变化的影响。结果表明,SFD导致东亚地区气温、降水和大气环流异常。12月和1月(DJ)青藏高原气温升高明显,反气旋环流异常导致西风环流在此期间减弱。在 2 月、3 月和 4 月 (FMA),SFD 导致高原及其东翼的温度升高以及北部广泛的异常冷却,这可归因于高层大气的非绝热冷却。热条件的这些变化导致 FMA 期间西风增强和东亚冬季风减弱。增强的西风给东亚大陆带来了更多的降水。在 5 月、6 月和 7 月(MJJ),东亚只有青藏高原显着变暖。此时西风环流减弱,东亚夏季风增强。低层大气环流显示南亚有异常的西风。来自中亚的异常西风带来干燥​​的空气,导致印度上空降水减少。这可以归因于高层大气的非绝热冷却。热条件的这些变化导致 FMA 期间西风增强和东亚冬季风减弱。增强的西风给东亚大陆带来了更多的降水。在 5 月、6 月和 7 月(MJJ),东亚只有青藏高原显着变暖。此时西风环流减弱,东亚夏季风增强。低层大气环流显示南亚有异常的西风。来自中亚的异常西风带来干燥​​的空气,导致印度上空降水减少。这可以归因于高层大气的非绝热冷却。热条件的这些变化导致 FMA 期间西风增强和东亚冬季风减弱。增强的西风给东亚大陆带来了更多的降水。在 5 月、6 月和 7 月(MJJ),东亚只有青藏高原显着变暖。此时西风环流减弱,东亚夏季风增强。低层大气环流显示南亚有异常的西风。来自中亚的异常西风带来干燥​​的空气,导致印度上空降水减少。增强的西风给东亚大陆带来了更多的降水。在 5 月、6 月和 7 月(MJJ),东亚只有青藏高原显着变暖。此时西风环流减弱,东亚夏季风增强。低层大气环流显示南亚有异常的西风。来自中亚的异常西风带来干燥​​的空气,导致印度上空降水减少。增强的西风给东亚大陆带来了更多的降水。在 5 月、6 月和 7 月(MJJ),东亚只有青藏高原显着变暖。此时西风环流减弱,东亚夏季风增强。低层大气环流显示南亚有异常的西风。来自中亚的异常西风带来干燥​​的空气,导致印度上空降水减少。

更新日期:2022-08-11
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