Subjects: Geosciences >> Geography submitted time 2024-06-12 Cooperative journals: 《干旱区研究》
Abstract： Reservoirs play a pivotal role in regional economic development and societal well-being. In recent years, Xinjiang has experienced frequent extreme precipitation events, posing significant challenges to reservoir safety. However, research on precipitation characteristics specific to Xinjiang's reservoirs remains limited, impeding scientific guidance for water resource utilization and reservoir management. Utilizing daily precipitation data from 1961 to 2022 and hourly precipitation data from 2009 to 2022 in the Xiagou Reservoir watershed of Yiwu County, Hami City, this study analyzed long-term variations in different time scales and precipitation levels. The findings indicate: (1) During the rainy season from 1961 to 2022, the average precipitation in the Xiagou Reservoir catchment area showed a weak increasing trend, and the number of days with no continuous precipitation showed a significant increasing trend. The total number of precipitation days and the maximum continuous precipitation days both show a significant decreasing trend. The increase in precipitation and the significant decrease in precipitation days may lead to further enhancement of precipitation intensity in the region. (2) The rainy season is mainly characterized by light rain, yet over the past 62 years, the number of light rain and moderate rain days has decreased while heavy rain and torrential rain days have increased. The highest proportion of rainstorm rainfall to the total rainfall in rainy season is close to 50.0%, and the increase of rainstorm rainfall is the main reason for the increase of rainfall in rainy season in Xiagou reservoir catchment area. (3) Daily precipitation displays a pattern of advancing high values as precipitation intensity strengthens. For instance, high values for light rain occur in the afternoon, moderate rain at midday, heavy rain in the morning, and torrential rain in the early morning. Except for torrential rain, high values for other precipitation levels are predominantly during the daytime. The daily variation curves for average precipitation intensity exhibit multiple peaks with significant differences. The relationship between cumulative precipitation frequency and cumulative precipitation amount is more closely associated with light and moderate rain than with precipitation intensity. Conversely, the relationship between average precipitation intensity and cumulative precipitation amount is more closely related to heavy and torrential rain than to cumulative precipitation frequency.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-09-14 Cooperative journals: 《干旱区研究》
Abstract：利用1981—2020年常规探空资料对塔里木东风低空急流进行了分析。结果表明：（1）塔里木东风低空急流平均每年出现74.2 d，整体呈减少趋势；平均风速为16.3 m·s-1，呈减小趋势；平均高度为1555.1 m，呈升高趋势；平均高层垂直风切变为9.94×10-3 s-1，低层为7.33×10-3 s-1，均呈减弱趋势。（2）塔里木东风低空急流的季节变化明显，其日数、风速和垂直风切变都是春季最多（强），夏季次之，冬季最小（弱）；高度则为冬季最高、秋季次之，春季最低。（3）塔里木东风低空急流的逐月差异较大，其日数和高层垂直风切变均在5月最多（强），12月最少（弱）；平均风速在5月最大，12月最小；平均高度在1月最高，4月最低；低层垂直风切变在4月最强，12月最弱。（4）塔里木东风低空急流的平均持续时间为2.3 d，夏季最长，冬季最短，出现次数随持续时间的增加而迅速减小，其中，持续1 d的塔里木东风低空急流出现次数最多，占总次数的48%；持续时间在3 d以内的出现次数占总次数的76.0%。位于内陆干旱区的塔里木东风低空急流，从上下层垂直风切变的分布特征来看，总体属于大尺度低空急流，与我国季风区的中尺度低空急流存在差异。
Subjects: Geosciences >> Geography submitted time 2021-06-13 Cooperative journals: 《干旱区研究》
Abstract：南疆暴雨是小概率事件，其预报预警的难度较大。南疆一些暴雨过程的历时短，降水强度大，并伴有短时强降水事件（即“短时强降水暴雨”）；而另一些暴雨过程的降水时间相对较长，未伴有短时强降水事件（即“非短时强降水暴雨”）。为探究南疆上述两类暴雨的差异，利用2013—2019年426个自动气象站逐小时降水资料，对比分析了南疆夏季短时强降水暴雨和非短时强降水暴雨的差异，结果表明：（1）南疆夏季以短时强降水暴雨为主，超过70%的站点在暴雨日中出现过短时强降水事件；短时强降水暴雨主要发生在7月，该月约95%的暴雨日中都出现过短时强降水事件。（2）南疆海拔在2000~2500 m的站点出现暴雨的比例最高，海拔低于1000 m的站点最低。南疆短时强降水暴雨主要发生在海拔低于2000 m的区域，非短时强降水暴雨则主要发生在海拔高于2000 m的区域，上述两类暴雨均具有明显的夜雨特征。（3）南疆总暴雨与短时强降水暴雨的累计降水量、降水频次和平均降水强度的日变化特征相似，二者与非短时强降水暴雨的差异较大。非短时强降水暴雨的累计降水量、降水频次和平均降水强度的峰值时段均出现在上午；短时强降水暴雨的累计降水量和平均降水强度的峰值时段出现在傍晚前后和前半夜，累计降水频次的峰值时段则主要出现在后半夜至清晨，短时强降水暴雨的降水强度与累计降水量的关系比降水频次更密切。南疆短时强降水暴雨和非短时强降水暴雨的观测特征存在显著差异，二者的降水形成机制也不相同。
Subjects: Geosciences >> Atmospheric Sciences submitted time 2021-04-13 Cooperative journals: 《干旱区地理》
Abstract： 利用 2008—2020 年自动气象站逐小时气温观测资料，研究了乌鲁木齐市主城区气温日变 化特征。结果表明：乌鲁木齐市主城区日最高气温主要出现在 14:00—17:00，日最低气温出现在 05:00—08:00。同一季节内，各月的日最高气温出现时次最大相差 1 h；日最低气温出现时次在冬季 各月间的差异较大，12 月和 1 月的日最低气温出现时间与 2 月相差 4 h。此外，12 月和 1 月的日最低 气温出现时间比其他月均早 2~3 h，与我国其他城市存在较大差异。乌鲁木齐市主城区各月的最 高气温出现频率的日分布曲线以“双峰”型为主，主峰时次为 15:00—18:00，次峰时次为 21:00，夏季 和冬季各月的日最高气温各时次出现频率的时间分布较为集中，春季和秋季相对分散。最低气温出 现频率的日分布曲线在春、夏、秋三季均呈“单峰”型，冬季峰值特征不明显。春、夏、秋 3 季的最低气温在 07:00—10:00 的出现频率较高，冬季 12 月和 1 月在 20:00 的出现频率相对较高。主城区 09:00— 12:00 的 1 h 正变温较大；18:00—22:00 的 1 h 负变温较大，正负变温存在不对称性，1 h 变温是乌鲁木 齐市主城区变温的主导者。乌鲁木齐市主城区冬季气温的日变化特征比其他3个季节更为复杂。
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