青藏高原月NDVI时空动态变化及其对气候变化的 响应

青藏高原脆弱的高寒植被对外界干扰十分敏感,使其成为研究植被对气候变化响应的理想区域之一。青藏高原气候变化剧烈,在较短的合成时间研究气候变化对植被的影响十分必要。因此,本文利用GIMMS NDVI时间序列数据集,研究了1982-2012年青藏高原生长季月尺度植被生长的时空动态变化,探讨了其与气温、降水量和日照时数等气候因子的响应关系。结果表明：在区域尺度上,除8月外,其他各月份植被均呈增加趋势,显著增加多发生在4-7月和9月;大部分月份的NDVI增加速率随着时段的延长显著减小,表明NDVI增加趋势放缓;在像元尺度上,月NDVI显著变化的区域多呈增加趋势,但显著减少范围的扩张多快于显著增加。4月和7月植被生长主要是受气温和日照时数共同作用,6月和9月受气温的控制,而8月则主要受降水量的影响。长时间序列NDVI数据集的出现为采用嵌套时段研究植被生长变化趋势奠定了前提,而植被活动变化趋势的持续性则有助于形象表征植被活动变化过程、深入理解植被对气候变化的响应和预测植被未来生长变化趋势。由此推测,青藏高原月NDVI未来增加趋势总体上趋于缓和,但在像元尺度显著变化的区域趋于增加。     

Human settlement evaluation in mountain areas based on remote sensing, GIS and ecological niche modeling

The Qinghai-Tibet Plateau is the world’s highest and largest plateau. Due to increasing demands for environment exploration and tourism, a large transitional area is required for altitude adaptation. Hehuang valley, which locates in the transition zone between the Loess Plateau and the Qinghai-Tibet Plateau, has convenient transportation and relatively low elevation. Our question is whether the geographic conditions here are appropriate for adapted stay before going into the Qinghai-Tibet Plateau. Therefore, in this study, we examined the potential use of ecological niche modeling (ENM) for mapping current and potential distribution patterns of human settlements. We chose the Maximum Entropy Method (Maxent), an ENM which integrates climate, remote sensing and geographical data, to model distributions and assess land suitability for transition areas. After preprocessing and selection, the correlation between variables and spatial autocorrelation input data were removed and 106 occurrence points and 9 environmental layers were determined as the model inputs. The threshold-independent model performance was reasonable according to 10 times model running, with the area under the curve (AUC) values being 0.917 ± 0.01, and 0.923 ± 0.002 for test data. Cohen’s kappa coefficient of model performance was 0.848. Results showed that 82.22% of the study extent was not suitable for human settlement. Of the remaining areas, highly suitable areas accounted for 1.19%, moderately for 5.3% and marginally for 11.28%. These suitable areas totaled 418.79 km², and 86.25% of the sample data was identified in the different gradient of suitable area. The decisive environmental factors were slope and two climate variables: mean diurnal temperature range and temperature seasonality. Our model showed a good performance in mapping and assessing human settlements. This study provides the first predicted potential habitat distribution map for human settlement in Ledu County, which could also help in land use management.     

青海省杂多—囊谦地区构造演化与聚煤作用分析

结合近年来在青藏高原取得的区域地质调查成果,利用卫星图像遥感解译,对青海省杂多—囊谦地区进行了煤田地质遥感综合分析,建立了区域构造格架,分析了构造演化和成煤古地理环境,探讨了构造对聚煤作用和赋煤状态的控制与影响。结果表明:研究区煤层聚集和赋存与羌塘地体构造演化密切相关,构造演化经历了5个阶段,区域构造活动较强;煤聚集场所分布于拗陷边缘地带,局部形成富煤带;煤系除遭受复杂的错断、变形外,同时还遭受较强的剥蚀作用;华力西运动对本区煤系改造影响最为强烈;石炭纪聚煤中心地带位于解曲大型区域断裂带北岸,共圈定了早石炭世含煤远景区3处,晚石炭世含煤远景区6处。     

2002-2012年青藏高原积雪物候变化及其对气候的响应

积雪是地表最活跃的自然要素之一,其动态变化对气候、环境以及人类生活都产生了重要影响。本文利用MODIS积雪产品和IMS雪冰产品,首先通过Terra、Aqua双星合成和临近日合成去除MODIS积雪产品中的部分云像元,再与IMS融合,获取了青藏高原2002-2012年逐日无云积雪覆盖产品,并逐像元计算每个水文年的积雪覆盖日数（SCD）、积雪开始期（SCS）和积雪结束期（SCE）,分析了不同生态分区积雪的时空变化特征,以及积雪开始期和结束期与温度、降水的关系。结果表明：青藏高原积雪分布存在明显的空间差异,南部喜马拉雅山脉和念青唐古拉山地区以及西部帕米尔高原和喀喇昆仑山脉为SCD的2个高值区,年均积雪日数在200 d以上。18.1%的区域SCS表现出明显的提前趋势,主要集中在青藏高原中东部;羌塘高原南部、念青唐古拉山西段以及川西地区有显著推迟趋势,占高原面积的8.5%。23.2%的区域SCE显著推迟,主要集中在果洛那曲高寒区、昆仑山区和念青唐古拉山地区;而仅有6.9%的区域表现出提前趋势,主要分布在高原西南部。总体上,不同生态单元内积雪开始与结束期受温度、降水的影响差异很大,表现出不同的空间格局与演变趋势。     

青藏高原植被变化特征及其对气候变化的影响

利用1982-2001年美国国家航天航空局(NASA)的归一化植被指数(NDVI)资料以及55个青藏高原地区气象台站实测的最高气温、最低气温、平均气温和降水资料,初步分析了青藏高原地区各季节植被变化特征及其对气候变化的影响,通过分析发现,各季节青藏高原地区NDVI均以增长为主.特别是高原南部、北部和西部等地区增加明显,高原中东部地区植被有所减少.通过相关分析和台站概率相关分析发现,高原冬季和春季NDVI与后期春季和夏季的最高气温、最低气温、平均气温和降水有较好的正相关关系,但有的表现在相关系数比较显著,有的表现为概率相关较明显.     

青藏高原冰雪消融区岩漠动态变化遥感监测研究现状与展望

青藏高原作为地球第三极增温明显,相关研究多集中于青藏高原冰雪动态,很少关注冰雪消融后岩漠的变化。岩漠通过地气相互作用影响着全球气候变化的区域差异。本文通过梳理青藏高原冰雪、冰雪消融区、岩漠动态变化遥感监测方法体系,着重分析了各遥感数据来源及提取方法的优缺点和适用性,并对基于遥感技术条件下青藏高原冰雪动态监测、冰雪消融区岩漠动态变化监测的数据来源、研究方法与技术进行了总结。目前,青藏高原冰雪动态变化遥感监测数据来源多样、研究方法成熟,而冰雪消融区岩漠动态变化遥感监测尚未形成系统研究。在人为干扰不明显背景下,青藏高原冰雪消融区岩漠的动态变化,在一定程度上也可作为对冰雪变化遥感监测的补充。     

Distribution,failure risk and reinforcement necessity of check-dams on the Loess Plateau: a review

Check-dams are the most important measure to control the soil and water loss in highly erodible catchments on the Chinese Loess Plateau.Based on the data of check-dams from 1950 to 2014,our study roundly analyzed the regional distribution,function and the problems of check-dams on the Loess Plateau.A total of 17,094 check-dams with a storage capacity of over 100,000 m³ and an average density of 0.027 counts km^-2 were installed on the Loess Plateau.Check-dams’densities varied greatly in the Qinghai Province,Gansu Province,Ningxia Hui Autonomous Region,Inner Mongolia Autonomous Region,Shaanxi Province,Shanxi Province and Henan Province.The highest density of check-dams reached 0.088 counts km^-2 in Shaanxi Province,whereas the lowest density of check-dams was only 0.005 counts km^-2 in Qinghai Province.However,after decades of operation,3025 large check-dams and 2257 medium check dams are dangerous and have security risks,which are seriously threatening downstream safety.The dangerous rate of checkdams is high.Specifically,the check-dams in Shanxi and Qinghai Province have the highest dangerous rates,with both exceeding 53%.Therefore,there is an urgent need for carrying out reinforcement of the dangerous check-dams.The results are helpful to policymakers to extend and develop check-dams.     

青藏高原旅游经济与生态环境协调效应测度及交互胁迫关系验证

青藏高原地区壮美的自然风光、神奇的人文景观和独特的民族文化,使其成为国内外旅游者倾心向往的世外桃源,亟需进一步探究其旅游经济与生态环境之间的交互耦合关系。本文创建青藏高原旅游经济与生态环境综合评价指标体系,采用青海省和西藏自治区15个地市州2000-2017年面板数据探究旅游经济与生态环境协调效应及交互胁迫关系。结果显示： ① 2000-2017年青藏高原仅有拉萨和西宁旅游经济指数呈现快速增长趋势,其余地市州均呈现缓慢增长趋势,生态环境指数整体较高,仅有西宁和海东呈现波动增长趋势,其余地市州变化平缓;② 青藏高原旅游经济与生态环境复合系统协调度时序上呈现波动增长趋势,空间上呈现南高北低、东高西低的分布格局;青海呈现以西宁为核心,逐层向外递减的核心-边缘空间格局;西藏呈现以拉萨为中心,南高北低的空间格局;③ 青藏高原复合系统协同效应子类型主要是旅游经济滞后型,西宁和拉萨呈现“旅游经济滞后-系统均衡发展-生态环境滞后”的变化趋势;④ 基于双指数模型证实了青藏高原旅游经济与生态环境之间具有交互胁迫关系。     

丽江地区旅游气候资源研究

通过对能代表丽江地区的丽江古城，云杉坪，石鼓3站的气候及其变化进行了分析，并计算和分析了3站逐月的舒适指数，得出：丽江古城近期气温升高，降水减少，丽江最适宜旅游的季节是5－8月，石鼓是4，5月和9，10月，云杉坪是7月。     

近50年中国地表净辐射的时空变化特征分析

基于GIS空间分析技术与Mann-Kendall趋势分析方法,对中国陆地区域699个气象站点1961-2010年逐年、季平均地表净辐射进行时空变化特征分析,结果表明:(1)参数拟合后的FAO Penman修正式对模拟站点逐日地表净辐射的总体精度较高,均方根误差为27.9W.m-2,相关系数为0.85,平均相对误差为0.13;(2)全国近50年站点平均地表净辐射在年、季均呈现出较明显的下降过程,年均降幅为0.74W.m-2.10a-1,不同季节的下降幅度存在差异,夏季降幅最大;(3)逐站点分析显示全国大部分站点(59.8%)年均地表净辐射呈显著下降趋势(0.05),东部趋势变化比西部明显,夏季在地表净辐射年际变化中的贡献最大,华北、华中、华南地区的站点在春夏秋季均呈显著下降趋势。     

基于CMIP6的中国未来高温危险性变化评估

评估高温灾害的危险性变化,能够为区域高温灾害风险管理和制定减灾措施提供决策依据。本研究选取高温日数、最高温度和平均高温强度3个指标,基于1961—2020年中国2517个气象站点日最高温数据和CMIP6情景模式比较计划中SSP2-4.5情景下12个气候模式提供的2031—2099年未来气候预测数据集,用核密度概率估计方法计算了4个重现期（即5、10、20和50年）下3个指标的取值,对中国未来高温危险性变化进行了评估。结果表明：① 在SSP2.4-5情景下,中国的高温日数呈现出4个危险中心,分别是：西北干旱（半干旱）地区中部、华北和华中地区的交汇区域、西南地区中部和华南地区南部,并且高温日数从这4个中心向外逐渐减少;最高温度在空间上的分布北部大于南部,东部大于西部。平均高温强度的分布则呈现出从华北地区南部、西北干旱（半干旱）地区西部和东部地区西部向我国除青藏高原地区外的其它地区减少的趋势; ② 在SSP2.4-5情景下,随着重现期年限的增长,中国地区3个高温指标均呈增长趋势且增幅较大,并且高值范围也在不断扩大;③ 3个高温指标变化值均呈现出了明显的空间聚集性,3个指标共同显示的热点区域包括西南地区北部和南部、西北干旱（半干旱）地区中部和华北、华中地区的少部分区域,这些地区发生高温灾害的可能最大,同时根据高温日数变化和最高温度变化,东部地区西部发生高温灾害可能也较大,3个指标共同显示的冷点区域包括青藏高原地区东南部、西北干旱（半干旱）地区的西部和我国东南沿海地区,这些地区几乎不会发生高温危险。     

Advance in Application of Regional Climate Models in China

Regional climate models have become the powerful tools for simulating regional climate and its change process and have been widely used in China. Using regional climate models, some research results have been obtained on the following aspects： 1） the numerical simulation of East Asian monsoon climate, including exceptional monsoon precipitation, summer precipitation distribution, East Asian circulation, multi-year climate average condition, summer rain belt and so on; 2） the simulation of arid climate of the western China, including thermal effect of the Qinghal-Tibet Plateau, the plateau precipitation in the Qilian Mountains; and the impacts of greenhouse effects （CO2 doubling） upon climate in the western China; and 3） the simulation of the climate effect of underlying surface changes, including the effect of soil on climate formation, the influence of terrain on precipitation, the effect of regional soil degradation on regional climate, the effect of various underlying surfaces on regional climate, the effect of land-sea contrast on the climate formulation, the influence of snow cover over the plateau regions on the regional climate, the effect of vegetation changes on the regional climate, etc. In the process of application of regional climate models, the preferences of the models are improved so that better simulation results are gotten. At last, some suggestions are made about the application of regional climate models in regional climate research in the future.     

灾害天气对若尔盖旅游安全影响的时间特征分析

利用若尔盖1971-2000年的大风、雷暴、冰雹、积雪、雾及飑的逐年各月气象资料,用现代统计方法,分别逐类、逐月、逐年代统计若尔盖地区旅游气象灾害出现频次、时间变化特征,并对其变化特征及主要旅游气象灾害发生规律进行气候综合分析,结合旅游安全社会经验,统计出若尔盖气象灾害发生月份集中在4-8月,主要是春、夏两个季节。而较少月份集中在8-2月,为秋、冬两季。若尔盖地区适宜旅游期月份为5、6、7、8、9月,非常适宜旅游区月份为6、7、8月,疗养期月份为7月。而该时段为灾害频发期,因此应特别注意对灾害天气的预防和应对。为当地旅游管理部门提供参考,为旅游投资与实施建设提供气象依据,为旅游者选择旅游季节及评估旅游安全提供帮助。     

中国气候舒适度时空分布特征分析

气候舒适度对人类活动和地区适宜性评价等研究具有重要意义,而温湿指数是气候舒适度评价的一项重要指标。传统的温湿指数计算都是基于站点数据,无法获取大尺度区域舒适度的时空变化特征。本文利用2005—2018年MODIS地表温度、大气可降水量数据,结合地理加权回归方法对经典温湿指数模型进行改进,计算并分析中国年均和月均气候舒适度时空演变特征。结果如下：① 采用GWR方法进行地表温度和气温的拟合,拟合精度（Adjusted R²=0.9~0.98,RMSE=0.14~1.89 ℃）较为理想,说明采用LST、NDVI、DEM作为自变量的地理加权回归分析,能够较精确地拟合地面气温;② 2005—2018年年均温湿指数统计结果表示,云南省累计舒适月数最多,高达167个月,中部省份相对于东南沿海省市舒适时期较多,最高舒适月数差值可达到41个月。中国年均舒适度空间分布规律基本保持一致,除新疆、西藏和东北的部分区域以外,舒适度空间呈现从南到北,舒适度等级由舒适变寒冷。从舒适度等级面积变化情况看,2005—2018年全国舒适度等级呈现由寒冷变舒适的趋势;③ 2018年全年舒适面积最大的月份为5月,其次为10月,不舒适月份集中在1月和7月,全国呈现极冷或极热。春季和秋季空间分布特征较为相似,呈现由东南到西北逐渐递减的趋势;除青藏高原地区外,夏季和冬季呈现由南到北递减趋势。舒适区域主要集中在低纬、中海拔地区。     

Karst cave tourism system in Zhejiang Province based on resource regional analysis

Karst cave tourism plays an important role in the overall tourism of Zhejiang Province,China.In analyzing the current status of karst cave tourism resources,it is crucial to develop a scientific system for optimizing resource exploitation and tourism development in the future.This study conducted an analysis of resource characteristics and regional structure in Zhejiang Province.Nearest neighbor index(NNI) method and accessibility index method were used for a comprehensive understanding of the effects of scale,strength,combination,and accessibility of karst cave tourism resources.Results indicated that karst cave tourism resources in Zhejiang Province have a significant regional influence,and that resource quality and exploitation are diverse in different regions.Among the regions,Jinhua had the highest exploitation proportion of over 60% and the lowest NNI value of 0.098.Furthermore,regional analysis inferred that different karst caves demonstrate diversity in accessibility to tourism markets,among which the Lingshan Cave,Fengshui Cave,and Xianqiao Cave reveal the highest accessibility index of 2.41.Finally,we put forward a karst cave tourism system in Zhejiang Province based on the Growth Pole Theory and set up an overall scheme for karst cave tourism development.From a regional perspective analysis,the study refined the methods for regional resource research and provided a strategic proposal for karst cave tourism in Zhejiang Province.     

川西高原马尔康旅游气候舒适度分析与评价

为了更好地发展旅游事业,在对马尔康旅游资源做出具体规划的同时,对当地的气候资源特征进行分析与评价。利用马尔康县气象站1966~2005年逐日气温、相对湿度、风速、降水量等观测资料,计算当地温湿指数、风寒指数、着衣指数、综合舒适指数等,进而对旅游气候舒适度进行定量分析与评价。研究结果表明:(1)马尔康地区温湿指数和风寒指数分别在7、8月份达最大值,着衣指数在7月份达最小值,人体在7月份感觉最舒适;(2)40a间,马尔康地区温湿指数,风寒指数和着衣指数总体变化较稳定,个别年份波动较大;(3)1966~1990年,舒适天数基本在125d左右波动;受全球变暖影响,1990~2005年马尔康舒适天数呈明显波动上升趋势。这说明马尔康夏季为最适宜旅游季节,全年大概有120d非常适宜旅游,旅游资源丰富,且气候变化对当地旅游资源开发有明显促进作用。     

青藏高原东北缘尖扎盆地沉积物矿物特征及其古环境意义

应用X射线衍射对青藏髙原东北缘尖扎盆地加让剖面11.8~5.8 Ma的地层沉积物进行矿物分析,结果表明加让剖面沉积物矿物组分主要包括碎屑矿物、碳酸盐矿物和黏土矿物。其中,以碎屑矿物居多,主要是石英、斜长石、云母类矿物(白云母、黑云母),及少量尖晶石、辉石类矿物(普通辉石、锰钙辉石及顽火辉石等)、金红石、刚玉、磁铁矿、钛磁铁矿、榍石、霞石,偶见锆石、石榴子石、锐钛矿;碳酸盐矿物以方解石居为主,白云石占比较少;黏土矿物中,绿泥石占比最高,还有少量赤铁矿、蛭石和沸石。以全岩矿物指标研究为主,结合加让剖面沉积相演化特点,并以磁化率变化为参考,进行系统的矿物学研究,获得了尖扎盆地在11.8~5.8 Ma蕴含的古气候环境演化大致可分为4个阶段:11.8~10.0 Ma,气候干冷期;10.0~8.6 Ma,气候暖湿波动期;8.6~6.2 Ma,气候温暖湿润期;6.2~5.8 Ma,气候干冷期。在约10.0、8.6、7.2 Ma附近,主要矿物占比及组合特征有明显改变,当时的古环境状况发生急剧变化,可能揭示青藏高原东北缘在10~8 Ma期间广泛发生了一系列较强烈的构造运动,来源于周边山脉的剥蚀使得研究区沉积的近源物质增多,约7.2 Ma之后的古环境演化过程主要受青藏高原构造隆升以及全球气候变冷协同影响。     

湛江观光农业发展研究

观光农业是以农业为依托 ,农业和旅游业相结合的一种新型交叉型的新兴产业。观光农业是随着经济的发展和旅游消费市场的需要而发展的 ,它为人们观光旅游、休闲健身、欣赏田园风光、享受农家乐趣等提供了新的空间场所。分析湛江发展观光农业的资源优势 ,提出了湛江观光农业的发展构想及注意问题 ,对湛江经济文化发展具有重要的意义。     

Simulating alpine vegetation net primary productivity by remote sensing in Qinghai Province,China

Primary productivity of ecosystem is important indicator about ecological assessment. Remote sensing technology has been used to monitor net primary productivity （NPP） of ecological system for several years. In this paper, the remotely sensed NPP simulation model of alpine vegetation in Qinghai Province of Tibet Plateau was set up based on the theory of light use efficiency. Firstly a new approach based on mixed pixels and Support Vector Machine （SVM） algorithm were used to correct simulated NPP values derived from Moderate Resolution Imaging Spectroradiometer （MODIS） data. Finally, spatial distribution and monthly variation characteristics of NPP in Qinghai Province detail. The result showed in 2006 were analyzed in that NPP of vegetation in Qinghai Province in 2006 ranged from o to 422 gC/m2/a and the average NPP was 151 gC/m2/a. NPP gradually increased from northwest to southeast. NPP of different vegetation types were obviously different. The average NPP of broad-leaved forest was the largest （314 gC/m2/a）, and sparse shrub was the smallest （101 gC/m2/a）. NPP in Qinghai Province significantly changed with seasonal variation. The accumulation of NPP was primarily in the period （from April to September） with better moist and heat conditions. In July, the average NPP of vegetation reached the maximum value （43 gC/m2）. In our model, the advantage of traditional LUE models was adopted, and our study fully considered typicalcharacteristics of alpine vegetation light use efficiency and environmental factors in the study area. Alpine vegetation is the most important ecological resource of Tibet Plateau, exactly monitoring its NPP value by remote sensing is an effective protection measure.     

Assessment of ecological importance of the Qinghai-Tibet Plateau based on ecosystem service flows

Assessments of ecological importance based on static indexes that do not consider service flows frequently underestimate the importance of the Qinghai-Tibet Plateau as a "source". On the basis of natural environmental characteristics, this study selected six type of ecosystem services for evaluation, including water retention, soil retention, carbon sequestration, biodiversity conservation, sandstorm prevention, and tourism. According to the attributes of each ecosystem service flow, we calculated the flow length and traffic accessibility indexes, using Arc GIS hydrological module and kernel functions separately, to comprehensively analyse the ecological importance levels of the Qinghai-Tibet Plateau. Results showed that after considering the service flows, the ecologically important zone shifted to the core area of the Three River Source Region, such as Zadoi County located in the Tanggula Mountains. The area of extreme importance is mainly distributed in the Yarlung Zangbo River basin, Tanggula Mountains, Hengduan Mountains, and Qilian Mountains, which accounts for 31.7% of the Qinghai-Tibet Plateau, providing approximately 60% of the ecosystem services and having extremely high protection efficiency and protection value. By introducing ecosystem service flow indexes, this study confirmed the ecological importance of core source areas such as the Tanggula Mountains, weakened the space bias caused by not considering the spatial transfer of ecosystem services, and provided technical support for optimizing ecological protection strategies and coordinating regional development.