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利用TM遥感影像解译土地利用状况、植被覆盖度,研究退耕还林前后的土地利用、植被覆盖度的变化,揭示陕西省吴起县退耕还林生态建设工程所取得的实效;利用吴起与周边6个气象站37年的气温和地温资料,分析吴起土地覆盖变化后对温度的影响。结果表明,随着退耕还林工程的实施,吴起县域版图在遥感影像逐渐显现、越来越清晰,植被覆盖增加极为显著,高覆盖植被面积在逐年增加,低覆盖植被面积在逐年减少,植被恢复情况明显好于周围区域。与1 997年相比,到2007年吴起县有75.15%耕地不再耕种,退出的耕地主要变为草地、林地和果园;林草覆盖率增加显著,由1997年的37.06%提高到2007年的80.60%。植被覆盖变化后,对地温和气温均产生了影响,变暖趋势得到下降,对夏季的影响大于冬季,夜间的影响大于白天。
The use of TM remote sensing image interpretation of land use, vegetation coverage, before and after the conversion of farmland to forest land use, vegetation cover changes, revealing Wuqi County, Shaanxi Province, the return of farmland to forest ecological construction projects made by the actual use of Wuqi and the surrounding 6 A weather station 37 years of temperature and geothermal data to analyze Wu Qi land cover changes on temperature. The results show that with the implementation of the project of returning farmland to forestland, Wuqi County territory gradually appears in the remote sensing image, more and more clear, the vegetation coverage increases extremely significantly, the area of high covered vegetation is increasing year by year, the area of low covered vegetation is decreasing year by year, The situation is clearly better than the surrounding area. Compared with 1997, 75.15% of arable land in Wuqi County was no longer cultivated by 2007, and the withdrawn arable land mainly turned into grassland, woodland and orchards. The coverage of forest and grass increased significantly from 37.06% in 1997 to 2007 80.60%. After the vegetation cover changes, it has an impact on the mild temperature of the earth, the warming trend is decreased, the impact on the summer is greater than that on the winter, and the impact at night is greater than that during the day.