兰州大学学报(自然科学版)
蘭州大學學報(自然科學版)
란주대학학보(자연과학판)
JOURNAL OF LANZHOU UNIVERSITY(NATURAL SCIENCES)
2014年
3期
376-382
,共7页
李凯%孙悦迪%江宝骅%郭建军%汪玉琼%岳东霞
李凱%孫悅迪%江寶驊%郭建軍%汪玉瓊%嶽東霞
리개%손열적%강보화%곽건군%왕옥경%악동하
植被覆盖度%滑坡%像元二分法%时空格局%白龙江流域
植被覆蓋度%滑坡%像元二分法%時空格跼%白龍江流域
식피복개도%활파%상원이분법%시공격국%백룡강류역
vegetation coverage%landslide%dimidiate pixel model%spatial-temporal structure%Bailongjiang River Basin
白龙江流域影响滑坡形成的主要因素包括地质构造、地形地貌、水文、气象、植被和人工干扰等,其中地表植被作为滑坡形成的主要外在因素对滑坡的形成和发展具有重要的作用,已引起学术界的广泛关注.以植被覆盖度为主要度量指标,选择2002,2005,2008,2011年4个时段的遥感N DV I值,在改进像元二分法的基础上,探讨了近10年来该流域地表植被覆盖度及其变化特征,并分析了其与滑坡点空间格局的关系.结果表明:该流域植被覆盖度总体变化微弱,但区域内部植被覆盖度变化具有明显的空间异质性,其中低覆盖区域覆盖度呈明显的增加趋势;而历年来,该流域植被覆盖度高的地区滑坡点密度均较低,滑坡点占总滑坡的20.6%,空间分布呈离散状态,而植被覆盖度低的地区滑坡密度较高,滑坡点占总滑坡的34.5%,空间分布主要呈聚集状态,说明白龙江流域植被覆盖度与滑坡点密度呈现负相关关系,植被覆盖度的高低是滑坡发生的一个主要影响因素.研究表明,近10年来,该流域低植被覆盖区域的植被覆盖度增加较快,说明在国家实施退耕还林还草政策后,该流域植被恢复较快,生态脆弱程度减轻,这将为地方防治滑坡灾害的发生起到积极的推动作用.本研究结论可为全流域制定宏观尺度上的滑坡生态防治策略提供科学依据.
白龍江流域影響滑坡形成的主要因素包括地質構造、地形地貌、水文、氣象、植被和人工榦擾等,其中地錶植被作為滑坡形成的主要外在因素對滑坡的形成和髮展具有重要的作用,已引起學術界的廣汎關註.以植被覆蓋度為主要度量指標,選擇2002,2005,2008,2011年4箇時段的遙感N DV I值,在改進像元二分法的基礎上,探討瞭近10年來該流域地錶植被覆蓋度及其變化特徵,併分析瞭其與滑坡點空間格跼的關繫.結果錶明:該流域植被覆蓋度總體變化微弱,但區域內部植被覆蓋度變化具有明顯的空間異質性,其中低覆蓋區域覆蓋度呈明顯的增加趨勢;而歷年來,該流域植被覆蓋度高的地區滑坡點密度均較低,滑坡點佔總滑坡的20.6%,空間分佈呈離散狀態,而植被覆蓋度低的地區滑坡密度較高,滑坡點佔總滑坡的34.5%,空間分佈主要呈聚集狀態,說明白龍江流域植被覆蓋度與滑坡點密度呈現負相關關繫,植被覆蓋度的高低是滑坡髮生的一箇主要影響因素.研究錶明,近10年來,該流域低植被覆蓋區域的植被覆蓋度增加較快,說明在國傢實施退耕還林還草政策後,該流域植被恢複較快,生態脆弱程度減輕,這將為地方防治滑坡災害的髮生起到積極的推動作用.本研究結論可為全流域製定宏觀呎度上的滑坡生態防治策略提供科學依據.
백룡강류역영향활파형성적주요인소포괄지질구조、지형지모、수문、기상、식피화인공간우등,기중지표식피작위활파형성적주요외재인소대활파적형성화발전구유중요적작용,이인기학술계적엄범관주.이식피복개도위주요도량지표,선택2002,2005,2008,2011년4개시단적요감N DV I치,재개진상원이분법적기출상,탐토료근10년래해류역지표식피복개도급기변화특정,병분석료기여활파점공간격국적관계.결과표명:해류역식피복개도총체변화미약,단구역내부식피복개도변화구유명현적공간이질성,기중저복개구역복개도정명현적증가추세;이력년래,해류역식피복개도고적지구활파점밀도균교저,활파점점총활파적20.6%,공간분포정리산상태,이식피복개도저적지구활파밀도교고,활파점점총활파적34.5%,공간분포주요정취집상태,설명백룡강류역식피복개도여활파점밀도정현부상관관계,식피복개도적고저시활파발생적일개주요영향인소.연구표명,근10년래,해류역저식피복개구역적식피복개도증가교쾌,설명재국가실시퇴경환림환초정책후,해류역식피회복교쾌,생태취약정도감경,저장위지방방치활파재해적발생기도적겁적추동작용.본연구결론가위전류역제정굉관척도상적활파생태방치책략제공과학의거.
Bailongjiang River Basin is one of the high incidence areas of geologic hazards in China, where landslides are widely distributed, which has a serious harmful effect on people’s life, property and local economic development. The main factors affecting the formation of a landslide includes its geological structure, landform, hydrology, meteorology, vegetation and artificial interference, etc. As one of the main external factors for landslide formation, vegetation plays an important role in the formation and development of landslides, which has attracted extensive attention from academic circles. The characteristics of vegetation coverage and its variations in recent 10 years were discussed here, based on the dimidiate pixel model with N DV I in 2002, 2005, 2008, 2011, and then their correlation with landslide was analyzed. The results showed that the changes in vegetation coverage had been generally small but in the region, it presented an obvious spatial heterogeneity, meaning that the low coverage regions thereof showed a trend of obvious increases. And over the years, the density of landslides had been low in regions with a high vegetation coverage, which accounted for 20.6% of the total landslides; and the density of landslides was high in regions with a low vegetation coverage, which accounted for 34.5% of the total landslides. All above showed that there is a negative correlation between the vegetation coverage and the density of landslides in Bailongjiang River Basin, and the vegetation coverage is one of the main influence factors to the formation of a landslide. The research showed that in recent 10 years, the vegetation coverage have been increasing quickly in regions with a low vegetation coverage at first, which means that after the implementation of the policy of returning farmland to forest and grass, the vegetation has recovered quickly and the ecological environment improved, which will play a positive role in the prevention and control of local landslides. The conclusion of this research will provide a scientific basis for landslide prevention strategies in the whole river basin.