| 乌鲁木齐达坂城谷地一次极端暴雪天气过程成因分析 |
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| 引用本文： | 万瑜,曹兴,李辉.乌鲁木齐达坂城谷地一次极端暴雪天气过程成因分析[J].新疆气象,2022,16(6):85-92. |
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| 作者姓名： | 万瑜 曹兴 李辉 |
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| 作者单位： | 新疆气象台,新疆气象局,乌鲁木齐市气象局 |
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| 基金项目： | 中国沙漠气象科学基金项目(Sqj2018007)；新疆自治区科技厅自然科学计划面上项目(2021D01A151) |
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| 摘 要： | 2018年3月17-18日乌鲁木齐达坂城谷地出现一次极端暴雪天气过程,降雪量达28.7 mm,为冬半年历年平均降水量的4.35倍,实属罕见。本文利用区域自动气象站小时监测资料、常规与加密观测资料、NCEP/NCAR再分析资料、FY-2G卫星相当黑体亮温(TBB)资料,分析此次极端暴雪天气过程。结果表明: 此次极端暴雪发生在3月中旬的初春时节,以500 hPa低涡、700 hPa西南低空急流、切变线及气旋性辐合中心、850 hPa偏北气流作为环流背景的低涡型暴雪；水汽来源主要是地中海、红海的水汽沿着偏西气流经波斯湾-阿拉伯海加强后,随低涡前西南气流输送至暴雪区,另一支通过北大西洋沿西南路径输送至中天山北坡中段,同时有由低涡前偏西气流接力输送的里、咸海水汽补充。2～4 km水汽密度较高,2 km水汽密度最大值为8 g/m3以上；850～700 hPa乌鲁木齐附近为强上升运动区,西北急流受天山阻挡强迫爬升,对中尺度垂直上升支起加强作用,为此次暴雪提供持续的动力支持；乌鲁木齐城区至达坂城一线受斜压不稳定增长,利于暴雪的持续与增强；中尺度云团是造成暴雪最直接的影响系统,强降雪区均位于中尺度云团的北至东北侧TBB等值线梯度最大区。
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| 关 键 词： | 达坂城谷地 极端暴雪 气候背景 致灾成因 |
| 收稿时间： | 2022/2/16 0:00:00 |
| 修稿时间： | 2022/6/16 0:00:00 |
Causal Analysis of An Extreme Snowstorm Process in Dabancheng Valley of Urumqi |
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| WAN Yu,CAO Xing and Li Hui.Causal Analysis of An Extreme Snowstorm Process in Dabancheng Valley of Urumqi[J].Bimonthly of Xinjiang Meteorology,2022,16(6):85-92. |
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| Authors: | WAN Yu CAO Xing and Li Hui |
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| Institution: | Xinjiang Meteorological Observatory,Xin Jiang Meteorological Administration,Urumqi Meteorological Administration |
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| Abstract: | An extreme snowstorm in Dabancheng Valley of Urumqi from March 17th to 18th in 2018 was analyzed. It was rare that 28.7 mm snowfall which was 4.35 of the average annual precipitation in winter half year. Using hourly observational data, the conventional and intensive detecting data, the NCEP reanalysis data and the FY-2G Satellite Bold Bright Temperature data, Results suggested as follows. The event occurred the early spring of mid-March, under the background that as with a low vortex at 500 hPa, a low-level southwest jet at 700 hPa, a shear line and a cyclonic convergence center and northerly flows below 850 hPa. The source of water vapor was mainly from the Mediterranean Sea and the Red Sea, which were strengthened by westerly flows through the Persian Gulf-Arab Sea, and transported to the snowfall area by southwesterly flows before the low vortex. Meanwhile, the other water vapor was transported to the middle of the northern slope of the Middle Tianshan Mountains along the southwest path through the North Atlantic, and was supplied by westward flows of the vortex. The water vapor density of 2-4 km was higher with the maximum more than 8 g/ m3. The strong ascending motion was near Urumqi at 850 -700 hPa. This vertical structure was conducive to the occurrence and strengthening of the snowstorm near Urumqi, and provided continuous dynamic support for the snow storm. From Urumqi to Dabancheng, the increasing of baroclinic instability was conductive to the maintaining and strengthening of the snowstorm. The mesoscale cloud cluster was the most direct influence system of snowstorm. Heavy snowfall areas were all located in areas with the maximum gradient of TBB, which were to the north and northeast side of the cloud cluster. |
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| Keywords: | Dabancheng valley extreme snowstorm climate background disaster cause |
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