雅鲁藏布江曲水-泽当段风沙活动动力条件分析与风沙灾害防治建议

雅鲁藏布江河流宽谷区是青藏高原风沙活动最为强烈地区之一。本文选择雅鲁藏布江曲水-泽当段为研究区，分析该地区1981—2010年以来的风动力条件变化特征。结果表明：1981年以来年平均风速明显降低，月平均风速2—4月最大。受河流-山地复合系统的影响，风向复杂且具有明显的空间差异性，贡嘎以西风和东风为主，泽当包括西风、南风和东北风。日极大风速超过起沙风速的天数所占比例较大（>83%），且自西向东逐渐增加（泽当达96%）。冬春季输沙势所占比例最大，扎囊地区年输沙势最大（77 UV），其次为桑耶地区（37 UV），泽当地区最小（5.4 UV）。近年来，沙尘天气有增加的趋势。风动力条件特点和该段河流宽谷区广泛分布的风沙沉积物是形成该区风沙地貌空间格局、导致沙尘天气频发的主要原因。基于该区河流-山地复合系统下风沙环境的复杂性和野外实地调查结果，提出了科学布置防沙治沙措施的建议。

Analysis on the sand transport wind power conditions and suggestions on the sand disaster preventions in the middle reaches of Yarlung Zangbo River,China

The wide valley area in Yarlung Zangbo River is one of serious aeolian disaster affected regions in Tibet Plateau.For this reason,the Yarlung Zangbo River(Qushui to Zidane)was selected as study region;wind power condition change was analyzed since 1981.The results indicated that averaged annual and monthly wind speed decreased since 1981.Wind speed is largest from February to April.Dust storm mainly occurred at winter and spring.Wind directions are complex for the river channel,sand land and mountains compound system in the study region and are primary west and east in the Gonggar,and west,south and northeast in the Zidane.The frequency of daily maximum wind speed larger than threshold wind speed is more than 83%for all stations,and these values increased from west to east,arrive to about 96%in Zidane.Drift potential is largest in the Zhanang(99 VU),and then Sangye(56 VU).The above mentioned complex wind power system and the widely distributed sediment in the river are the main reasons for spatial distributions of aeolian geomorphology and frequently occurrence of dust storm.Based on the complex wind power system for the river channel,sand land and mountains compound system,we provide some suggestions for the rational sand disaster prevention.