沙尘暴的成因与防治

沙尘暴天气的形成要具备三个基本条件：

there are three basic conditions for the formation of sandstorm:

一是要有沙源。

first, there should be a source of sand,

二是要有强冷空气即大风。

second, there should be strong cold air, i.e. strong wind,

三是要有冷暖空气相互作用。沙源来自于沙漠，退化的林草地或没有植被覆盖的干松土地以及城乡建筑工地的泥沙。气旋和低压产生一种垂直的上升运动，把沙尘吹扬了起来，形成沙尘暴天气。扬沙、浮尘和沙尘暴天气的差别在气象上是以能见度加以区分的：水平能见度在1—10公里之间的为扬沙或浮尘天气。出现浮尘天气时，空中弥漫的是一些细小颗粒物，沙尘多由外地而来；扬沙天气卷起的尘土是一些较大的颗粒物，它们基本是本地产生的。而水平能见度小于1公里的就是沙尘暴天气，它属于灾害性天气现象，所带来的危害最为严重。气象专家介绍，由于沙尘暴起因包括了风力、高空大气强对流和地表状态三方面因素，而前两者属气候因素，人力不可抗拒，因此，根除沙尘暴目前尚无可能。

third, there should be interaction between warm and cold air. the source of sand comes from deserts, degraded forest and grassland, or dry pine land without vegetation cover, as well as the sediment of urban and rural construction sites. the cyclone and the low pressure produce a vertical upward movement, which blows up the dust and forms a dust storm. the weather difference of sand blowing, floating dust and sandstorm is distinguished by visibility in meteorology: the weather with horizontal visibility between 1-10km is sand blowing or floating dust. when the floating dust weather occurs, the air is filled with some small particles, most of which come from other places; the dust rolled up by the floating dust weather is some larger particles, which are basically generated locally. the sandstorm with horizontal visibility less than 1km is a kind of disastrous weather phenomenon, which brings the most serious harm. according to meteorologists, the causes of sandstorm include wind force, high-altitude atmospheric strong convection and surface state, while the former two are climatic factors and irresistible by manpower, so it is impossible to eradicate sandstorm at present.

沙尘暴引起的风灾、沙积、风蚀，使森林和植被遭到破坏，沙漠化程度加剧。气象专家提醒，人类对风沙天气最积极、最有效的行为是：首先要加强对大风天气的监测和预报工作，特别是在前期干旱的情况更要重视。其次，对于西安这样一个旅游大都市来讲，在突发性灾害来临之前，要有相当有效的应急对策，加强管理和强化预防措施。对全省而言最根本的还是要进行综合治理工作。全社会共同行动起来，治理沙漠，改善生态环境。我们在搞好经济建设的同时，要注重生态建设。每个公民要有强烈的忧患意识，环境保护意识，而且应多加强这方面的教育，从而真正做好植树造林，扩大植被覆盖率，开源节流，合理利用水资源。特别是我们陕西，是西部大开发的桥头堡，应当把实行“退耕还林（草），封山绿化，个体承包，以粮代赈”为主要措施，争取早日实现米粮下川，林果上山，草场满坡，使三秦大地山绿、水清、人富。逐渐恢复自然丰富多样的生态系统。这样，也许再过几十年，沙尘暴将淡化为我们的记忆，我们的子孙后代看到的将是一个山川秀美的大西北。

the wind disaster, sand accumulation and wind erosion caused by sandstorm damage the forest and vegetation, and aggravate the degree of desertification. meteorological experts remind that the most active and effective behavior of human beings is to strengthen the monitoring and prediction of gale weather, especially in the early drought. secondly, for xi'an, a tourist metropolis, there should be quite effective emergency response measures, strengthen management and strengthen preventive measures before unexpected disasters. for the whole province, the most fundamental thing is to carry out comprehensive governance. the whole society should act together to control deserts and improve the ecological environment. while doing well in economic construction, we should pay attention to ecological construction. every citizen should have a strong sense of hardship and environmental protection, and should strengthen the education in this area, so as to do a good job in afforestation, expand the vegetation coverage, open up resources and reduce expenditure, and make rational use of water resources. shaanxi, in particular, is the bridgehead of the western development. we should take the implementation of "returning cultivated land to forest (grass), closing mountains and greening, inspanidual contracting, and grain for relief" as the main measures to strive for the early realization of grain to sichuan, fruit to mountain, grassland to slope, so that the land of sanqin is green, clear and rich. gradually restore the natural rich and spanerse ecosystem. in this way, maybe in a few decades, the sandstorm will fade into our memory, and our descendants will see a beautiful northwest.