最近，我国北方地区多次出现场沙或沙尘暴天气，究其原因，乃是西北地区严重沙漠化的结果。我国现在沙漠及沙化面积达１６８． ９万平方公里，每年还以２４６０平方公里的速度扩展。风沙每年造成的直接经济损失达５４０亿元，外加植被破坏，水土流失，给一些大江大河造成了严重 Recently, there have been many occasions of field sand or sandstorms in northern China. The reason for this is the result of the serious desertification in the northwest region. China now has an area of ​​168 deserts and desertification. 90,000 square kilometers, an annual expansion of 2,460 square kilometers. The direct economic loss each year caused by sandstorms amounts to 54 billion yuan, plus vegetation damage and soil erosion have caused serious problems for some major rivers