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题名 气候变暖背景下河西地区荒漠植被变化研究(1982-2013)
姓名 杨雪梅
院系 资源环境学院
专业 生物地理学
学位名称 理学博士
外文题名 Spatial-temporal Variations of Desert Vegetation and its Response to Climate Change in Hexi area during 1982-2013
第一导师姓名 杨太保
关键词 气候变化;荒漠植被;NDVI;物候;时空变化格局;影响因子;河西地区
外文关键词 Climate change;Desert vegetation;NDVI;Phenology;Spatio-temporal variations;Impact factors;Hexi area
学科 理学
摘要 利用1982-2006年GIMMS NDVI数据和2000-2013年MODIS NDVI数据,反演1982-2013年甘肃省河西地区荒漠植被时空变化格局。以及2000年以来河西地区荒漠植被返青期、枯黄期以及生长季长度时空变化格局,探讨气侯变暖对河西地区荒漠植被产生的影响。结果显示:1982-1999年荒漠植被以保持稳定为主,2000-2013年52.11%的区域呈显著改善趋势,但是也存在植被退化区面积增加的现象。河西地区疏勒河流域和石羊河流域荒漠植被改善区域主要发生在中下游地区。1982-2013年,河西地区典型荒漠植被改善状况较山地荒漠植被明显。2000-2013年荒漠植被返青期和枯黄期整体上呈不显著的-6.2 d/10a和-1.8 d/10a提前趋势,生长季长度呈不显著的2.77 d/10a增加趋势。石羊河和黑河流域荒漠植被返青期和枯黄期均以提前为主,疏勒河流域均呈推迟趋势,生长季长度石羊河流域增加最明显。山地荒漠植被返青期和枯黄期的提前趋势、生长季长度的增加趋势较典型荒漠植被相对明显。3-8月份累积降水量是河西地区荒漠植被生长的主控气候因子,气温对荒漠植被生长状况的影响相对较小。可能由于山地荒漠植被耐旱能力较低,再加上受到地形等因素的影响,部分地区汇水条件差,因此降水量对山地荒漠植被的影响较典型荒漠植被明显,春季降水量和冬季≥0℃积温是植被返青的主控气候因子。
外文摘要 In this study, we adopted and integrated GIMMS NDVI (1982–2006) and MODIS NDVI (2001–2013) remote sensing data to analyze spatial-temporal variations of desert vegetation and its response to climatic changes in the Hexi area, Gansu Province during 1982-2013. In addition, the model of desert vegetation phenology has been constructed, which includes GD (Greenup Date), SD (Senescence Date) and LG (Length of Growth Season), and the spatial-temporal variations of desert vegetation phenology, furthermore its response to climate changes was also been analyzed. The results of this research reveal that: the desert vegetation activities mostly remain stable in the Hexi area from 1982 to 1999 (PhaseⅠ), which was significantly improved in 52.11% of the area during 2000-2013 (PhaseⅡ), except for individual areas that was suffered desertification increasing in the PhaseⅡ.The desert vegetation had been largely stable in different river basins during the PhaseⅠ, however, the improvement trend occurred in all river basins especially in the Shule River Basin of the western Hexi area during the PhaseⅡ. The vegetation improvement phenomenon mainly occurred in the middle and lower reaches of the Shule River Basin and the Shiyang River Basin. During the period of 1982 to 2013, the significant restoration area of typical desert vegetation accounted for 40.7% of the total typical desert vegetation regions, which was higher than that of the mountain desert vegetation (18.45%). As a whole, there were insignificant advancing ratios observed for the GD and the SD, respectively, with -6.2d/10a and -1.8 d/10a during 2000-2013, and insignificant prolonged ratio of the LG was 2.77 d/10a. The GD and the SD have advanced tendency in the majority of the Shiyang River and the Heihe River basin, but the change was different in the Shule River Basin from 2000 to 2013. Besides, the advanced tendency of the GD, the SD, and extension of the LG of the mountains desert vegetation were relatively obvious than that of the typical desert vegetation.The main factors for vegetation growth were precipitation of spring and summer, the vegetation growth was affected by precipitation during March and August that covered about 95% of the total desert vegetated land, and the temperature had little effect on the growth of desert vegetation. the mountain desert vegetation growth was influenced more significantly by precipitation than the typical desert vegetation, because of lower drought-resistance...
研究领域 生态遥感和GIS应用,全球变化
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