弱风背景下阵风起沙对大气沙尘气溶胶总量的贡献  

Contribution of dust emission from gust to total dust aerosol under weak wind conditions

作　　者：韩超信 韩永翔[2] 李嘉欣 Han Chaoxin;Han Yongxiang;Li Jiaxin(Lanzhou Meteorological Bureau,Lanzhou 730030,China;Nanjing University of Information Science and Technology,Nanjing 210044,China)

机构地区：[1]兰州市气象局,甘肃兰州730030 [2]南京信息工程大学,江苏南京210044

出　　处：《中国沙漠》2025年第1期259-265,共7页Journal of Desert Research

基　　金：国家自然科学基金面上项目(42275077)。

摘　　要：沙尘气溶胶排放量是研究气候和环境变化的核心参量。利用2021年腾格里沙漠1 min风速数据,基于通用的起沙方案,计算了强风背景下沙尘暴和弱风背景下阵风的起沙量。结果显示:(1)阵风具有明显的湍流结构和随机性,年内大于临界起沙风速的频率约占总数的6%,10 min和1 h的平均风速难以捕捉弱风背景下的阵风起沙。(2)强风背景下沙尘暴起沙量是弱风背景下阵风起沙量的5~100倍,但阵风起沙量的累积效应不容忽视。(3)非沙尘期,阵风起沙机制起支配作用,而沙尘期,沙尘暴起支配作用;沙尘暴和阵风对年度起沙总量的贡献分别为45%和55%,表明阵风起沙机制在沙尘排放中占据重要地位。弱风背景下阵风导致的巨量沙尘气溶胶对气候和环境变化的影响亟须进行重新评估。Total dust aerosol emission is one of the most critical factors in the study of climate and environmen-tal change.The dust emission mechanism of power-dominated dust storms can only explain the amount of dust aerosols during dust storms,but not the presence of large amounts of dust aerosols during non-dust storms,im-plying that there may be other dust emission mechanisms in addition to the dust storm emission mechanism.Us-ing the 1-min high-resolution wind speed observation data of Tengger Desert in 2021,we calculate the dust emis-sions from gusts in a weak wind background and from dust storms in a strong wind background based on the gen-eralized Gillette dust emission scheme.The results show that:(1)Gusts have obvious turbulence structure and randomness,and the frequency of wind speeds greater than the critical dust-raising speed accounts for about 8%of the total annual wind speeds,and the wind speed of 10-min and 1-h average is difficult to capture gusts dust emission in the context of weak winds.(2)Dust emission from dust storm is 5-100 times that of gusts,but the cumulative effect of gust should not be ignored,which is one of the main sources of dust aerosols in the atmo-spheric background.(3)The gust emissions are absolutely dominant in the non-dusty months,while the dust storm emissions are dominant in dusty months.In terms of the contribution to the total annual dust emissions,the contribution of dust storms is 45%while that of gusts is 55%,which suggests that the cumulative effect of dust emissions from gusts plays an important role in further refining the existing dust emission mechanism,and that the impacts of its huge amount of dust aerosols on the climate and environmental changes are in need of urgent re-assessment.

关 键 词：阵风起沙 沙尘气溶胶 沙尘通量 沙尘暴 贡献率 

分 类 号：P425.6[天文地球—大气科学及气象学]