共查询到17条相似文献,搜索用时 183 毫秒
1.
利用卫星遥感资料和地面气象观测资料,基于CASA模型及其他数理方法估算了浑善达克沙地2000-2013年生长季(4-10月)植被净初级生产力(NPP),并对其时空变化特征进行了分析,讨论了气候因子和人类活动对植被净初级生产力的影响。结果表明: 14年间,研究区生长季的植被净初级生产力呈波动中增加趋势,多年平均NPP为239.8 gC·m-2·a-1。整个研究区表现为高NPP值(大于150 gC·m-2·a-1)的植被面积在增加,低NPP值(小于150 gC·m-2·a-1)的植被面积在减少。在空间分布上,研究区的北部、中部和南部边缘区域的植被NPP增加趋势较明显,而东部和西部部分区域未发生明显的趋势性变化。总体而言,研究区植被净初级生产力变化趋势与降水量的关系更密切,其相关系数达到0.86,是驱动植被NPP年际波动的最直接因素。而与温度呈负相关,相关系数为-0.42。综合考虑气候因素和人类活动对沙地NPP的影响发现,温度降低、种饲料面积、年末牲畜存栏头数和羊的数量的减少是NPP值提高的关键因素。 相似文献
2.
利用2000年的Landsat5遥感数据、1970年和2009年的冰川编目数据, 对天山中段南坡开都河流域和北坡玛纳斯河流域的冰川变化进行了对比分析, 并结合地面气象站点数据分析了冰川对气候变化的响应及南北坡冰川变化的差异性. 研究表明: 1970-2009年间, 两流域冰川面积减少了494.33 km2, 占总面积的26.8% (0.8%·a-1); 冰川储量减少了32.73 km3, 占总储量的27.9% (0.8%·a-1). 其中, 2000-2009年冰川面积和冰储量年退缩率(1.3%·a-1)比1970-2000年(0.6%·a-1)大; 冰储量减少的速率略大于面积缩小的速率, 说明冰川面积缩小的同时, 其厚度在迅速减薄. 1970-2000年和2000-2009年间, 玛纳斯河流域的冰川年均面积退缩率分别为0.5%·a-1和1.4%·a-1, 开都河流域的冰川年均面积退缩率为0.9%·a-1和1.1%·a-1, 显示出玛纳斯河流域冰川在2000年后呈加速萎缩趋势. 影响研究区冰川变化的主因是气温, 而夏季升温幅度及降水的不同是造成南北坡冰川差异性变化的重要原因. 相似文献
3.
青海省天然草地退化及其环境影响分析 总被引:6,自引:0,他引:6
根据青海省"三江源地区"和"环青海湖地区"典型生态区域1987-2004年代表性牧草观测站植被监测资料和地面气象数据,结合NOAA/AVHRR卫星遥感数据以及调查数据,分析了两区域十几年来草地退化特征.结果表明:中度以上退化草地面积平均以20×104hm2·a-1的速度递增,草地生产力<750 kg·hm-2的草地面积占全省面积的26.99%.三江源地区牧草产量以4.48~16.48 kg·a-1趋势减少,高度以0.16~0.80 cm·a-1的趋势降低,优势牧草株数的线性递减率分别为11株.a-1和16株.a-1,莎草科牧草开花期和籽粒成熟期的发育百分率下降25~50个百分点;环青海湖地区牧草产量以3.05~4.64 kg·a-1趋势减少,高度以0.75~1.28 cm·a-1趋势降低,以禾本科牧草为代表的优良牧草在群落中的比重分别下降了1%~3%,位于青海湖以南地区的温性草原类和温性荒漠类,递减率分别为0.25%·a-1和0.38%·a-1.青海省天然草地退化主要是在自然和人为因素等作用下发生的,在自然因素中气候的暖干化趋势是草地退化的重要因素,表现在影响牧草的生育期、产量以及草地的群体结构的变化,而20世纪90年代以来极端天气、气候灾害的增多,进一步加剧了草地的退化;人为控制因素中,表现在草畜季节不平衡造成的超载过牧、人口增长以及草地不均匀的放牧压力等,进一步加剧天然草地生态功能的退化. 相似文献
4.
帕隆藏布流域位于中国海洋性冰川发育最为集中的藏东南地区,近年来随着全球气候变暖,帕隆藏布流域冰川亏损显著。利用全球开放冰川模型(OGGM)模拟了1980—2019年藏东南地区帕隆藏布流域1 554条冰川物质平衡,发现1980—2019年帕隆藏布流域全域冰川物质平衡呈现不断亏损的状态,为-0.41 m w. e.·a-1,在2000—2019年物质平衡亏损更为严重,达到-0.56 m w. e.·a-1。从空间分布上来看,流域东南部和流域西北部是冰川亏损最为严重的区域,流域中部和西部冰川亏损相比较少。温度的升高和降水的轻微减少是冰川物质亏损的主要原因。通过气温和降水的敏感性分析,气温上升1℃,流域71.75%的冰川物质平衡变化在-1 000~-500 mm w. e.·a-1;降水减少20%,62.81%的冰川物质平衡变化在-450~-300 mm w. e.·a-1,相较于降水,冰川对气温变化更为敏感。通过分析国家气象站及再分析数据,发现1980—2019年气象站气温上升均超过1.5℃,波密站200... 相似文献
5.
遥感技术根据植被光谱特征可以有效地估算植被的净初级生产力(NPP)。利用遥感数据估算植被NPP,是近10 年来NPP的模型研究和估算方法最为突出的特点。文章借鉴了CASA,GLO-PEM,VPM等光能利用率NPP模型的优点,同时充分考虑了研究区域其植被光能利用率和环境因素的典型特点,建立了针对研究区域基于光能利用率原理的植被净初级生产力遥感估算模型。在此基础上,模拟了青海省2006年逐月植被 NPP,较深入地分析了NPP的空间分布和季相变化特征。研究结果表明,2006年青海省植被净初级生产力介于0~422gC/m2/a之间,平均值为151gC/m2/a; 青海省NPP空间分布规律总体上呈由西北向东南地区递增的趋势; NPP在不同植被类型中的差异相当明显,单位面积平均NPP最高的为阔叶林(314gC/m2/a),最低的为稀疏灌丛(101gC/m2/a); 青海省NPP随季节的推移变化显著,NPP的积累期主要发生在水热搭配较好的4~9月份,7月植被平均NPP达到最大值(43gC/m2)。 相似文献
6.
基于2009年5-10月喜马拉雅山北坡珠峰绒布冰川流域实测水文气象数据、 50 m分辨率DEM和中国第一次冰川编目资料, 在HYCYMODEL水文模型中加入冰川消融子模块, 模拟了绒布冰川流域径流过程.冰川消融子模块以海拔5 180 m基站的实测日气温、 日降水作为模型输入, 把气温、 降水插值到该流域40个高程带中, 分别计算各高程带的冰川消融和裸地蒸发, 并考虑液态降水对冰面的加热作用.野外气象观测表明: 2009年5-10月流域海拔5 180~5 750 m内, 月气温递减率在0.63~0.73 ℃·(100m)-1之间, 均值为0.70 ℃·(100m)-1; 同期降水观测显示, 海拔5 180 m以下降水梯度为-7.3 mm·(100m)-1, 该高度之上降水梯度为22 mm·(100m)-1. HYCYMODEL水文模型的敏感性检验表明, 该流域径流变化主要受气温影响, 降水变化引起的径流变化较小, 气温和降水变化对流域径流的影响是非线性的. 相似文献
7.
青海湖流域生态补偿空间选择与补偿标准研究 总被引:3,自引:1,他引:2
生态补偿是环境保护对策措施中的一种创新途径.以青海湖流域为研究区域, 以碳蓄积量作为主要生态系统服务目标, 结合人文调查数据和自然模拟结果, 分别采用福利成本法和最小数据方法对研究区生态补偿中的空间选择和补偿标准确定进行了分析.结果表明: 环青海湖四个县的生态补偿效率成本比分别是海晏县0.5353、 刚察县0.5398、 天峻县0.5549、 共和县0.4353.在生态补偿资金有限的情况下, 生态补偿的优先顺序依次是天峻、 刚察、 海晏, 最后是共和.若海晏县全部低盖度草地退牧则需付费328.5元·hm-2·a-1, 可年新增碳固定量1.7×107 kg; 若刚察县全部低盖度草地退牧则需付费250.5元·hm-2·a-1, 可年新增碳固定量5.25×107kg; 若天峻县全部低盖度草地退牧则需付费181.5元·hm-2·a-1, 可年新增碳固定量18.52×107kg; 若共和县全部低盖度草地退牧则需付费478.5元·hm-2·a-1, 可年新增碳固定量2.86×107kg. 相似文献
8.
1971—2000年中国陆地植被净初级生产力的模拟 总被引:4,自引:0,他引:4
利用植被与大气相互作用模式(AVIM),基于气象台站的观测资料模拟了1971—2000年中国陆地生态系统NPP的变化特征.结果表明:1971—2000年我国陆地植被年均NPP变化范围在0~987.67 gC·m-2·a-1,全国平均值为349.74 gC·m-2·a-1,30 a呈现出递增的变化趋势.对各类植被NPP的模拟显示,最近30 a我国热带雨林、落叶阔叶林以及有地被层的阔叶林的年均NPP减小,而混交林、常绿针叶林、落叶针叶林、有裸土的灌丛、草地以及作物的年均NPP均为增加趋势.由于采用了先进的农业技术,与自然条件下我国作物的年均NPP变化相比,我国实际的粮食单产在上述时期呈显著的增长,表明了人类活动对于我国陆地植被净初级生产力有着深刻的影响. 相似文献
9.
基于GIS的玛旁雍错流域冰川地貌及现代冰川湖泊变化研究 总被引:11,自引:0,他引:11
基于多源多时相的数字遥感影像、地形图和DEM数据,利用遥感(RS)和地理信息系统(GIS)技术,对西藏玛旁雍错流域冰川地貌类型和空间分布进行了研究,并对流域内近30 a来冰川和湖泊的变化进行分析.结果表明:1974-2003年玛旁雍错流域冰川总面积减少了7.27 km2,平均退缩速率0.24 km2·a-1;湖泊总面积减少37.58 km2,平均退缩速率1.25 km2·a-1.多时相的监测表明,冰川在加速退缩,且阳坡冰川的消融速度大于阴坡,坡度陡、面积小的冰川消融比例大于坡度缓、面积较大的冰川;湖泊面积先减少后有所增加,但总面积还是减少了,不少小湖泊消失.分析流域附近气象资料可知,气温上升和降水量减少是玛旁雍错流域内冰川消融与退缩的主要原因. 相似文献
10.
1960-2010年黑河流域冰川变化的遥感监测 总被引:8,自引:6,他引:2
利用1960年地形图、 1990年、 2000年和2010年TM影像, 采用基于冰雪指数(NDSII)和原始波段的面向对象解译方法, 提取黑河流域4个时期的冰川分布, 结合30 m分辨率的DEM数据, 利用遥感、 地理信息系统技术对冰川的时空分布变化及原因和不确定性进行分析. 结果表明: 从1960-2010年50 a间黑河流域上游冰川持续退缩, 面积共减少138.90 km2, 减少率为35.6%, 平均每年减少2.78 km2, 祁连山中段冰川属于强烈退缩型. 祁连山中段黑河流域冰川主要分布在海拔4 200~5 300 m之间, 冰川分布下限为海拔4 000 m; 冰川退缩主要发生在低海拔地区, 冰川的退缩上限为海拔4 600 m.气温的显著上升是研究区冰川退缩的关键因素, 气候持续变暖将会导致冰川退缩加剧. 相似文献
11.
The Thornthwaite Memorial, Synthetic, and Carnegie Ames Stanford Approach (CASA) models, with inputs from SPOT-VGT-S10 NDVI
data, meteorological data (precipitation, temperature, solar radiation), and land use data were used to estimate the values
of net primary productivity (NPP) from 1999 to 2007 in China’s Shiyanghe Basin. The human appropriation of NPP, which represents
the difference between potential NPP predicted using the climatic models and actual NPP calculated using the CASA model, served
as the indicator of human intervention in the evolution of productivity of the land. Analysis showed that 78.9% (~9,172 km2) of the degradation occurring in the Shiyanghe Basin was caused by human activities versus 15.0% (~1,752 km2) that was caused by climatic factors, whereas 16.9% (~6,404.5 km2) of the vegetation restoration resulted from human activities versus 49.7% (~18,881 km2) that resulted from climate changes. Human activity played a key role in vegetation restoration in the central areas of the
basin and in determining land degradation in the southwestern and northeastern areas. In addition, climate significantly controlled
the vegetation restoration in the southwestern and northeastern areas and controlled land degradation in the central area. 相似文献
12.
Based on the data developed from various s natural waters in the Qinghai Lake area and ostracode shells present in drill core QH-16A of recent lake-floor sediments ,this paper discusses the distribution of stable isotopes in the modern water body of Qinghai Lake,and the initial isotopic composition of the lake water has been deduced ,Studies of δ^18O,δ^13C,Mg/Ca and Sr/Ca in ostracode shells provide the basis for the establishment of the model of climatic fluctuation in the Qinghai Lake area since the postaglacial age,as well as for the elucidation of the environmental evolution of the water body of Qinghai Lake since the postglacial age. 相似文献
13.
2013年西藏嘉黎县“7.5”冰湖溃决洪水成因及潜在危害 总被引:11,自引:3,他引:8
冰湖溃决洪水(泥石流)是西藏自治区主要自然灾害之一. 2013年7月5日,西藏自治区嘉黎县忠玉乡发生“7.5”冰湖溃决洪水灾害事件,导致人员失踪,房屋被毁,桥梁、道路等基础设施遭到严重破坏,直接经济损失高达2.7亿元. 基于不同时间段地形图和遥感影像资料,利用地理信息技术,发现导致“7.5”洪灾的溃决冰湖为然则日阿错. 该冰湖溃决的直接诱因可能是雪崩和冰崩的共同作用,溃决前的强降水过程及气温的快速上升是其间接原因,而冰湖长期稳定的扩张导致水量聚集是其溃决并造成巨大灾害的基础. 然则日阿错溃决后形成2个冰湖,面积分别为0.25 km2和0.01 km2,再次发生溃决的概率极小. 这次溃决洪水和泥石流灾害事件阻塞了尼都藏布的罗琼沟及衣布沟,并形成2处面积分别为0.33 km2和0.13 km2堰塞湖,且存在溃决风险,在今后一段时间内应加强监测工作与排险工程实施. 相似文献
14.
Quantitative assessment of the contributions of climate change and human activities on global grassland degradation 总被引:5,自引:0,他引:5
Chengcheng Gang Wei Zhou Yizhao Chen Zhaoqi Wang Zhengguo Sun Jianlong Li Jiaguo Qi Inakwu Odeh 《Environmental Earth Sciences》2014,72(11):4273-4282
Grassland degradation received considerable concern because of its adverse impact on agronomic productivity and its capacity to provide goods and service. Climate change and human activities are commonly recognized as the two broad underlying drivers that lead to grassland degradation. In this study, a comprehensive method based on net primary productivity (NPP) was introduced to assess quantitatively the relative roles of climate change and human perturbations on worldwide grassland degradation from 2000 to 2010. The results revealed that at a global scale, 49.25 % of grassland ecosystems experienced degradation. Nearly 5 % of these grasslands experienced strong to extreme significant degradation. Climate change was the dominant cause that resulted in 45.51 % of degradation compared with 32.53 % caused by human activities. On the contrary, 39.40 % of grassland restoration was induced by human interferences, and 30.6 % was driven by climate change. The largest area of degradation and restoration both occurred in Asia. NPP losses ranged between 1.40 Tg C year?1 (in North America) and 13.61 Tg C year?1 (in Oceania) because of grassland degradation. Maximum NPP increase caused by restoration was 17.57 Tg C year?1 (in North America). Minimum NPP was estimated at 1.59 Tg C year?1 (in Europe). The roles of climate change and human activities on degradation and restoration were not consistent at continental level. Grassland ecosystems in the southern hemisphere were more vulnerable and sensitive to climate change. Therefore, climate change issues should be gradually integrated into future policies and plans for domestic grassland management and administration. 相似文献
15.
Peijuan Wang Donghui Xie Yuyu Zhou Youhao E Qijiang Zhu 《Environmental Earth Sciences》2014,71(2):647-658
The ecological structure in the arid and semi-arid region of Northwest China with forest, grassland, agriculture, Gobi, and desert, is complex, vulnerable, and unstable. It is a challenging and sustaining job to keep the ecological structure and improve its ecological function. Net primary productivity (NPP) modeling can help to improve the understanding of the ecosystem, and therefore, improve ecological efficiency. The boreal ecosystem productivity simulator (BEPS) model provides the possibility of NPP modeling in terrestrial ecosystem, but it has some limitations for application in arid and semi-arid regions. In this paper, we improve the BEPS model, in terms of its water cycle by adding the processes of infiltration and surface runoff, to be applicable in arid and semi-arid regions. We model the NPP of forest, grass, and crop in Gansu Province as an experimental area in Northwest China in 2003 using the improved BEPS model, parameterized with moderate resolution remote sensing imageries and meteorological data. The modeled NPP using improved BEPS agrees better with the ground measurements in Qilian Mountain than that with original BEPS, with a higher R 2 of 0.746 and lower root mean square error (RMSE) of 46.53 gC m?2 compared to R 2 of 0.662 and RMSE of 60.19 gC m?2 from original BEPS. The modeled NPP of three vegetation types using improved BEPS shows evident differences compared to that using original BEPS, with the highest difference ratio of 9.21 % in forest and the lowest value of 4.29 % in crop. The difference ratios between different vegetation types lie on the dependence on natural water sources. The modeled NPP in five geographic zones using improved BEPS is higher than those with original BEPS, with higher difference ratio in dry zones and lower value in wet zones. 相似文献
16.
Centennial blooming of anoxygenic phototrophic bacteria in Qinghai Lake linked to solar and monsoon activities during the last 18,000 years 总被引:1,自引:0,他引:1
Junfeng Ji William Balsam Ji Shen Man Wang Hongtao Wang Jun Chen 《Quaternary Science Reviews》2009,28(13-14):1304-1308
The productivity of anoxygenic phototrophic bacteria (APB) can be inferred in the sediments of Qinghai Lake from the changing abundance of bacteriophaeophytin a (Bph-a). Using diffuse reflectance spectroscopy (DRS), we identified Bph-a in Qinghai Lake sediments from the late glacial period through the Holocene with a resolution of one sample every 30–50 years. The Bph-a profile of Qinghai Lake demonstrates that in the last 18,000 years APB were only present between 4.2 and 14 ka BP, a period of high rainfall and high summer solar insolation. All the APB blooming events correspond to times of enhanced freshwater influx as revealed by percent redness, an indicator of the input of iron oxide minerals. Our data suggest that solar insolation sets the stage for APB blooms, which are then promoted by increased summer monsoon rainfall and nutrients resulting in the development of a chemocline in the lake. The blooming of APB in Qinghai Lake appears as discrete centennial-scale APB events likely linked to solar activities. Our results suggest the presence of solar-induced, century-long, intense summer monsoon episodes in the middle and early Holocene and the late glacial period. 相似文献
17.
基于青海高原1961 - 2018年47个气象站昼夜雨量数据, 分析了青海高原及各生态功能区的昼夜雨量及雨日的时空变化特征。结果表明: 近58年来, 青海高原昼夜雨量空间分布基本一致, 总体表现为东南向西北减少, 夜雨日多于昼雨日分布。青海高原昼夜雨量总体均呈增多趋势, 昼雨量的增加速率大于夜雨量; 从空间分布来看, 柴达木盆地西部、 东部农业区大部及青南牧区南部少数地区昼夜雨量呈减少趋势, 而柴达木盆地东部、 环青海湖地区、 青南牧区大部昼夜雨量均呈增多趋势。青海高原昼雨日略有增加, 夜雨日有减少趋势; 在地域上, 柴达木盆地昼夜雨日增多趋势明显, 而东部农业区昼夜雨日减少趋势明显。青海高原昼夜雨量分别呈2 a、 3 a的周期。近58年来, 青海高原、 东部农业区、 环青海湖地区、 柴达木地区昼雨量均无明显的突变现象, 仅青南牧区昼雨量在2003年前后存在明显突变现象; 青海高原、 东部农业区、 青南牧区夜雨量无明显突变现象, 环青海湖地区、 柴达木盆地夜雨量分别在1979年、 2003年出现了突变现象。 相似文献