摘要:
气候变化是中国北方地区荒漠化形成发展的主要控制因素.新生代以来伴随着青藏高原的隆升和内陆盆地的下降逐渐形成的气候格局造就了北方地区荒漠化土地的分布.北方西部内陆盆地以干旱气候为主要特征,中部高原是受季风系统中夏季风和冬季风的消长变化影响最为显著的地区,东部地区则以暖湿气候为主,受夏季风控制.第四系以来气候的波动则控制着沙漠化的发展或逆转.末次间冰期以来一直持续的大约以1500a为周期的气候振荡对中国北方地区的沙漠化有重要的影响或控制作用.全新世以来,北方地区约在10000aBP、8000aBP、5500aBP、4000aBP、3000aBP、1500aBP的沙漠化过程分别与北大西洋第7、5、4、3、2和1次的浮冰事件相应,沙漠化扩大过程与全球气候变化的主要事件相一致.十年尺度上气候变化的周期性振荡对沙漠化有一定的影响,至少在生态环境脆弱的敏感地带对沙漠化可以起到控制作用.年际尺度上,6.7a和3.38a气候变化周期控制着我国北方地区沙尘暴的发生.此外,北方不同地区近150a以来的人类活动对沙漠化的扩大起到了重要作用.
关键词:
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全新世
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气候变化
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中国北方
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沙漠化
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周期性
Abstract:
Climate change is a main control factor for the formation and development of desertification in north China. The climate pattern established during the up lift of the Qinghai-Tibet plateau and the descent of in land basins basically built up the distribution of desertified land in north China since Cenozoc. The climate in inland basins is arid,central China plateau is featured by semi-arid climate prominently con-trolled by the East A sian monsoon system while east China is dominated by worm and humid climate influ-enced by summerwind. The Quaternary climate variations have controlled desert expansion and reverse. Since last interglaciation, on going climate oscillations characterized by a 1 500 a cycle have dominated desertification in north China. Desertification at about 10,000 aBP, 8,000 aBP, 5,500 aBP, 4,000 aBP, 3,000 aBP and 1,500 aBP respectively corresponds to Numbers 7,5,4,3,2,and 1 floatingice events occurring in the North Atlantic Ocean, identical to the global climate fluctuation events. Cyclic climate changes at decade scale affect desertification to some extent, at leastin some sensitive zoneswhere theecological environment is fragile. Cycliic climate oscillations at annual scale such as 6.7a and 3.38a may be important to dust storm. Furthermore, human activities are responsible for desertification expansion in many areas during last 150 years.
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