方祖亮,俞小鼎,王秀明. 2020. 东北暖季干线统计分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2020.024
东北暖季干线统计分析
Statistical Analysis of Warm Season DryLines in Northeast China
投稿时间:2019-07-01  修订日期:2019-12-18
DOI:10.11676/qxxb2020.024
中文关键词:  东北,干线,暖季,统计
英文关键词:Northeast China, Dryline, Warm season, Statistical analysis
基金项目:国家自然科学基金面上项目
作者单位E-mail
方祖亮 中国气象科学研究院 fangzuliang17@mails.ucas.ac.cn 
俞小鼎 中国气象局气象干部培训学院 xdyu1962@126.com 
王秀明 中国气象局气象干部培训学院 wangxm@cma.gov.cn 
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中文摘要:
      基于常规地面观测、高空观测和卫星雷达资料,对2003-2017年东北地区暖季(5-8月)干线时空分布、气象要素等进行了统计分析。研究发现,东北地区干线主要出现在东北平原和辽宁西部,干线发生频率呈现南多北少的趋势。干线大多呈西南东北走向,宽度约为90-120km,长度在100-800km。东北区域暖季年均干线发生频率为15.5%。干线发生频率年际变化不明显,年均逐旬变化显著且呈正弦曲线状,其中5月中下旬-6月下旬和8月中下旬为波峰,干线发生频率在20%以上,7月低于10%,为波谷。干线湿侧气压相比干侧略高1hPa,两侧温度大多在24℃以上,温差一般在1-4℃,露点梯度和比湿梯度范围分别为9.6-15℃/100km和4.5-8.3g/(kg·100km),相当位温梯度在9.6-19K/100km左右。干线 两侧要素及其梯度值逐旬变化显著,其中两侧湿度、温度和湿度梯度值从5月到8月呈增大趋势,而温度梯度绝对值呈减小趋势。在共计286例干线中有40%的干线触发了对流,6月中上旬干线触发对流比率最高,达60%以上。干线是否触发对流与其所在位置关系不大。对流干线湿度梯度略大于无对流干线。无对流干线和对流干线探空要素的最显著的区别表现在湿侧CAPE值上,前者湿侧CAPE在1200J/kg以下,后者湿侧CAPE值基本都在1200J/kg以上,最高甚至能达到3000J/kg左右。
英文摘要:
      Based on the conventional surface observation, soundings, satellite and radar data, the temporal and spatial distribution and the meteorological elements of the drylines in the warm season (May-August) in the Northeast China(40-53°N, 115-135°E) are analyzed during a 15-y period from 2003-2017. The research shows that the drylines of the Northeast China are mainly in the northeast plain and the west of Liaoning, and the frequency of drylines is more in the South than in the north. Most of the drylines are in the southwest-northeast direction, with a width of 90-120 km and a length of 100-800 km. The annual average frequency of drylines in warm season in Northeast China is 15.5%.The frequency of dryline occurrence has no obvious interannual change, but the annual change is significant and presents sinusoidal curve. The frequency of dryline is more than 20% from mid-late May to late June and mid-late August, which is the peak, and less than 10% in July, which is the trough. The air pressure on wet side of dryline is slightly higher than that on dry side by 1 hPa, and the temperature on both sides is mostly above 24 ℃. The temperature difference between the two sides is generally between 1 and 4 ℃. The dew point gradient and specific humidity gradient range are 9.6-15℃/100km and 4.5-8.3g/(kg·100km), respectively. The equivalent potential temperature gradient is about 9.6-19K/100km.The time series of the elements and their gradient values on both sides of the dryline changes significantly. The temperature,humidity on both sides and gradient values of humidity increase from May to August, while the absolute value of temperature gradient decreases.In a total of 286 drylines, 40% of the drylines triggered convection. In the middle and early June, the triggered convection ratio of the dryline was the highest, reaching more than 60%.Whether or not the dryline triggers convection has little to do with its location. The humidity gradient of convective drylines is slightly larger than that of non-convective drylines.The most significant difference of sounding elements between non-convective drylines and convective drylines lies in the value of CAPE on the wet side. The former is below 1200 J/kg on the wet side, while the latter is above 1200 J/kg on the wet side, with the highest value reaching about 3000 J/kg.
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