This study assessed whether dust-storm frequency during major droughts in New South Wales (NSW), Australia, has changed and what may have caused any change. The frequency of days with dust storms, i.e. when visibility is <1000 m, is presented for the dust storm year (July to June), with the maximum number of dust storms for three major droughts, namely, 2017/20, Millennial and World War II droughts. Community attitudes, government policy and land management practices have changed since the 1940s, and these factors were reviewed to determine whether they explain changes in dust-storm frequency. Two data sources were used: meteorological weather codes from the Australian Bureau of Meteorology and dust particulate matter <10 µm (PM10) from the DustWatch/Rural Air Quality Monitoring Network. The particulate-matter data were converted to dust-storm days (DSD) to create a yearly time series. The meteorological data records were coded as dust storms and required no modification. Results showed that 1944/45 was the dustiest year, with 4.4 times more DSD than in 2019/20 and 9.9 times more DSD than in 2009/10. One reason for the higher DSD in 2019/20 than in 2009/10 was the area protected from wind erosion by vegetation cover above 50%. In 2019/20, 69% of NSW was protected from wind erosion, compared with 79% in 2009/10. We suggest the primary reasons for lower DSD in 2019/20 and 2009/10 than in 1944/45 were community attitudes, government policy and land management practices; these, in combination, help maintain vegetation cover. Since the 1940s, the focus of land management has changed from ‘taming the land’ to ‘sustainably using the land’. Government policy in the 2000s is focused on supporting farming businesses and communities to manage and prepare so as to successfully manage drought. Land management practices that maintain ground cover are now widely practised.

这项研究评估了澳大利亚新南威尔士州 (NSW) 大旱期间的沙尘暴频率是否发生了变化，以及可能导致变化的原因。出现沙尘暴的天数，即能见度<1000 米时，呈现沙尘暴年（7 月至 6 月），沙尘暴次数最多的是 2017/20 年、千禧年和世界三大干旱二战干旱。社区态度、政府政策和土地管理实践自 1940 年代以来发生了变化，对这些因素进行了审查以确定它们是否可以解释沙尘暴频率的变化。使用了两个数据源：来自澳大利亚气象局的气象天气代码和来自 DustWatch/农村空气质量监测网络的小于 10 µm (PM10) 的尘埃颗粒物。颗粒物数据被转换为沙尘暴天数 (DSD)，以创建年度时间序列。气象数据记录被编码为沙尘暴，不需要修改。结果显示，1944/45 年是尘埃最多的一年，DSD 是 2019/20 年的 4.4 倍，是 2009/10 年的 9.9 倍。2019/20 年 DSD 高于 2009/10 年的原因之一是植被覆盖率超过 50% 的风蚀保护面积。2019/20 年，新南威尔士州 69% 的地区免受风蚀，而 2009/10 年这一比例为 79%。我们认为 2019/20 年和 2009/10 年 DSD 低于 1944/45 年的主要原因是社区态度、政府政策和土地管理做法；这些结合起来有助于维持植被覆盖。自 1940 年代以来，土地管理的重点已经从“驯服土地”转变为“可持续利用土地”。2000 年代的政府政策侧重于支持农业企业和社区进行管理和准备，以成功应对干旱。维持地面覆盖的土地管理做法现已广泛实施。