College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
Environ Pollut. 2020 May;260:114084. doi: 10.1016/j.envpol.2020.114084. Epub 2020 Jan 31.
Northern China is a significant source of dust source in Central Asia. Thus, high-resolution analysis of dust storms and comparison of dust sources in different regions of northern China are important to clarify the formation mechanism of East Asian dust storms and predict or even prevent such storms. Here, we analyzed spatiotemporal trends in dust storms that occurred in three main dust source regions during 1960-2007: Taklimakan Desert (western region [WR]), Badain Jaran and Tengger Deserts (middle region [MR]), and Otindag Sandy Land (eastern region [ER]). We analyzed daily dust storm frequency (DSF) at the 10-day scale (first [FTDM], middle [MTDM], and last [LTDM] 10 days of a month), and investigated the association of dust storm occurrences with meteorological factors. The 10-day DSF was greatest in the FTDM (accounting for 77.14% of monthly occurrences) in the WR, MTDM (45.85%) in the MR, and LTDM (72.12%) in the ER, showing a clear trend of movement from the WR to the ER. Temporal analysis of DSF revealed trend changes over time at annual and 10-day scales, with mutation points at 1985 and 2000. We applied single-factor and multiple-factor analyses to explore the driving mechanisms of DSF at the 10-day scale. Among single factors, a low wind-speed threshold, high solar radiation, and high evaporation were correlated with a high DSF, effectively explaining the variations in DSF at the 10-day scale; however, temperature, relative humidity, and precipitation poorly explained variations in DSF. Similarly, multiple-factor analysis using a classification and regression tree revealed that maximum wind speed was a major influencing factor of dust storm occurrence at the 10-day scale, followed by relative humidity, evaporation, and solar radiation; temperature and precipitation had weak influences. These findings help clarify the mechanisms of dust storm occurrence in East Asia.
中国北方是中亚沙尘源区的重要组成部分。因此，对中国北方不同地区沙尘暴的高分辨率分析和沙尘源的比较，对于阐明东亚沙尘暴的形成机制、预测甚至预防此类沙尘暴具有重要意义。在这里，我们分析了 1960-2007 年三个主要沙尘源区（塔克拉玛干沙漠西部[WR]、巴丹吉林沙漠和腾格里沙漠中部[MR]和浑善达克沙地东部[ER]）沙尘暴的时空变化趋势。我们分析了 10 天尺度上的沙尘日频率（DSF）（上旬[FTDM]、中旬[MTDM]和下旬[LTDM]），并调查了沙尘日与气象因子的关系。WR 中上旬的 10 天 DSF 最大（占每月发生次数的 77.14%），MR 中中旬（45.85%），ER 中下旬（72.12%），呈明显从 WR 向 ER 移动的趋势。DSF 的时间分析显示，在年际和 10 天尺度上都存在时间变化趋势，在 1985 年和 2000 年出现了突变点。我们应用单因素和多因素分析来探索 10 天尺度上 DSF 的驱动机制。在单因素中，低风速阈值、高太阳辐射和高蒸发与高 DSF 相关，有效解释了 10 天尺度上 DSF 的变化；然而，温度、相对湿度和降水对 DSF 的变化解释较差。同样，使用分类回归树的多因素分析表明，最大风速是影响 10 天尺度上沙尘暴发生的主要因素，其次是相对湿度、蒸发和太阳辐射；温度和降水的影响较弱。这些发现有助于阐明东亚沙尘暴发生的机制。
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