本文利用地面常规、区域加密自动站及高空观测等资料,对哈密市伊州区2023年4月18~20日一次区域性强大风、沙尘暴天气过程从天气学角度进行诊断分析,得出结论。结果表明:大风沙尘暴天气发生在有利的气候背景下,高空斜压槽及强锋区和地面冷锋是触发强风沙的重要天气系统。前期持续增温为其提供了有利的热力条件;高空急流动量下传、强气压梯度区和变压差是大风沙尘暴产生的动力条件。大风沙尘暴发生区域,对流中低层存在不稳定层结,加剧了低层辐合、高层辐散的垂直运动发展;地面气象要素的强烈变化可作为大风沙尘暴预报的重要参考依据和着眼点。数值预报产品具有一定的预报能力,但预报量级和影响时间存在偏差。Based on the ground routine observational data, regional encrypted automatic station observational data and upper air observation data, a regional strong wind and sandstorm weather process was diagnostic analyzed from meteorological perspective in Yizhou District of Hami from April 18~20, 2023. The results showed that the wind and dust storms occur in the favorable climate background, and the cold front on the ground is the important weather system to trigger the strong wind and sand. The continuous warming in the early stage provides favorable thermal conditions;the momentum of the upper air jet streams transmission downwards, strong pressure gradient and pressure difference are the dynamic conditions of gale dust storms. In the area where gale sandstorm occur, there is unstable stratification in the middle and low levels of convection, which intensifies the vertical movement development of low-level convergence and high-level divergence;the strong change of ground meteorological elements can be used as an important reference basis and starting point for gale sandstorm forecast. Numerical prediction products have a certain prediction ability, but there are deviations in the forecast magnitude and influence time.
本研究利用1981~2023年北京地区15个气象观测站的数据,分析了北京“数九寒天”期间的气温变化特征。研究发现“数九”期间气温呈“V”型分布,验证了“三九严寒”的说法,温差近8℃。整个研究期间北京“数九寒天”有显著增温趋势,年均增温0.0603℃/年,尤其在“三九”、“八九”和“九九”时段。研究时段极端最低气温也呈上升趋势,但增温速率较小。气温空间分布呈“南高北低、西低东高”格局,受地形和城市化影响,城市热岛效应显著。全球变暖和城市化导致北京“数九寒天”特征显著改变,对城市管理和居民生活产生影响。建议加强极端气温事件预测、研究城市化对气温的影响、扩大研究区域、评估气候变化对各领域的影响,以适应气候变化。This study analyzed the temperature change characteristics during the “nine coldest days” by using data from 15 meteorological observation stations in the Beijing area from 1981 to 2023. The study found that the temperature during the “nine coldest days” showed a “V”-shaped distribution, verifying the saying of “the severe cold in the third nine-day period”, with a temperature difference of nearly 8˚C. During the entire study period, there was a significant warming trend during the “nine coldest days” in Beijing, with an average annual warming rate of 0.0603˚C per year, especially in the “third nine-day period”, the “eighth nine-day period” and the “ninth nine-day period”. The extreme minimum temperature also showed an upward trend during the study period, but the warming rate was relatively small. The spatial distribution of temperature presented a pattern of “higher in the south and lower in the north, lower in the west and higher in the east”. Affected by topography and urbanization, the urban heat island effect was significant. Global warming and urbanization have led to significant changes in the characteristics of the “nine coldest days” in Beijing, which have an impact on urban management and residents’ lives. It is recommended to strengthen the prediction of extreme temperature events, study the impact of urbanization on temperature, expand the research area, and evaluate the impact of climate change on various fields in order to adapt to climate change.
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