2008年南方冰雪过程对生态环境影响的遥感监测——以湖南省资兴市为例

2008年1月中下旬至2月上旬,我国南方地区出现了大范围、长时间的强降雪及冰冻灾害。这次冰冻雨雪灾害,不仅对广大人民群众的生活和社会经济运行造成了极大破坏,而且对当地生态环境也产生了深刻影响。本文以湖南省资兴市为例,运用遥感技术和地面野外调查相结合的方法,监测了本次冰雪过程对当地生态环境的影响。监测发现:本次冰雪过程对植被覆盖破坏显著,植被指数呈较大范围降低趋势,降低区域的总面积占资兴市土地总面积的54.12%;森林生态系统受损严重,除灌木林外302.2万亩森林全部受灾,其中,针叶林比阔叶林严重,幼龄林比成熟林严重,外来种比乡土树种严重,人工林比天然林严重;冰雪过程后土壤含水量增加、边坡失稳,地质灾害危险程度明显增高,工程建设区和林缘陡坡地带以滑坡(崩塌)为主的地质灾害频频发生。     

中国西北地区植被NDVI的时空变化及其影响因子分析

利用GIMMS/NDVI数据分析了中国西北地区1982-2006年植被NDVI时空变化特征及其影响因子。近25年来,中国西北地区年均植被NDVI增速为0.5%/10a,并存在明显的空间差异。天山、阿尔泰山、祁连山、青海的中东部等地区植被NDVI显著增加;青海南部地区、陕西和宁夏交界地区、甘肃部分地区,以及新疆部分地区的植被NDVI下降。从不同植被类型看:林地、草地和耕地的年均NDVI都在提高。研究表明:中国西北地区植被NDVI变化是各种自然和人为因素综合作用的结果。植被NDVI与气温、降水的年际变化整体上都呈弱的正相关。但与其年内变化则都呈显著的线性关系,当月均温量超过20℃时,植被NDVI呈下降趋势;当月降水量在0¹00mm期间,植被NDVI随降水线性增长,当月降水量超过100mm之后,不再有明显的增长趋势。农业生产水平提高和植被生态建设等人类活动对西北地区植被NDVI增加有重要影响。     

齐家文化时期(4200～3600 cal. a BP)青藏高原高庙盆地植被重建及与现今对比

高庙盆地是青藏高原史前文化重要活动区域,也是青藏高原东北缘植被垂直地带性最为显著的地域,是揭示自然环境与人类活动相互作用的典型区域。对高庙盆地店子坪遗址剖面开展了年代学与孢粉研究,重建了齐家文化时期的区域植被状况。结果表明:孢粉组合以松属、云杉属、蒿属为主,并伴有少量桦属、鹅耳枥属、榆属、沙棘属、藜科、菊科;结合高庙盆地现今地貌与植被分布特征,推测齐家文化时期(4 200～3 600cal.a BP)盆地内植被类型为森林草原,低阶地以松林为主,并有少量的榆、鹅耳枥和桤木等温带落叶阔叶性树种,属于温性针阔混交林,高阶地及中山地为以蒿属为主的温性草原,沟谷阴坡则可能生长以松、云杉为主的针叶林;与现今植被相比,青藏高原东北缘河谷地带低阶地现今已无松林,全被杨树林等人工林替代,云杉、松分布区较齐家文化时期显著萎缩,仅在中—高山地带呈岛状不连续分布,推测历史时期人类活动可能是青藏高原东北缘河谷地带植被变化的重要驱动力。     

多孔介质中聚合物溶液的流变特性

为研究多孔介质中高剪切条件下聚合物溶液流变性能的影响,利用驱 替装置和 R S6000 流变仪 测试不同 的注入速度、 渗流距离和孔喉比条件下, 聚合物溶液经过多孔介质 剪切前后 流变性的 变化. 结果 表明: 聚合物 的剪切应 力、表观黏度、 储能模量、 损耗模量等参数随着注入速度、 渗流距离和孔喉比增加而减小, 且在低剪切速率 和低角频率下 表观黏度、 储能模量、 损耗模量下降更为明显, 剪切应力下降幅度较小, 而在高剪切 速率下剪 切应力下 降幅度最 大; 渗流距 离对聚合物黏弹性作用的影响最大, 其次为注入速度, 孔喉比对聚合物黏弹性作用的影响较小.     

1980—2020年济南市土地利用变化对生态系统服务价值的影响

面对资源紧缺、土地利用方式不合理、生态系统退化等问题,探索土地利用变化对生态系统服务价值的影响,对于制定适宜的国土空间规划、自然资源管理、生态文明建设等方面的政策措施具有重要意义。本文选取济南市作为研究区域,探讨了1980—2020年研究区土地利用结构变化以及土地利用类型间转移情况,并核算了生态系统服务价值,分析了不同土地利用类型对生态系统服务价值变化的生态贡献率。研究结果表明：(1)在研究时段内,研究区建设用地面积呈现持续增加的趋势;在1980—2000年阶段,耕地、林地、草地、水域面积呈现波动式变化,在2000—2020年阶段处于持续下降的趋势。(2)1980—2020年,生态系统服务总价值呈先下降后上升再下降的趋势;从单项服务价值来看,供给、调节、支持和文化4种主要的服务价值均有不同程度的减少,尤其在2005—2010年,下降幅度最大。(3)耕地对济南市生态系统服务价值变化影响最大,主要由于研究区内受城市发展的影响,导致耕地面积大幅减少,其次影响较大的是林地、草地和水域。     

南方亚热带季风区将乐县森林植被动态变化及其对气候变化的响应

在全球气候变化背景下,植被动态变化以及植被对气候变化的响应方式已经成为生态学和地理学领域的热点。本文对比分析了南方亚热带季风区将乐县不同类型森林植被对不同时间尺度的干旱响应的差别。基于2000-2017年MODIS-EVI数据及气象站点数据,用最大值合成法、趋势分析法以及相关分析法,分析了森林植被及气象因子的动态变化特征,并对比不同森林植被对气候变化响应的差别。研究表明：① 2000-2017年,研究区植被覆盖度、EVI和降水均显著增加,区域内湿度增加,森林长势渐趋良好;② EVI在生长季初期和末期与同期的降水、温度均显著正相关（P<0.1）,初期森林受降水因子的影响更大,末期受温度因子的影响大;③ 1-3月和周年的气候变化对森林的生长至关重要,长时间尺度的湿度增加对森林生长具有显著的促进作用,SPEI的时间尺度越长与EVI的相关性也越大;④ 针阔混交林与同期温度、降水的相关系数最高,并且与不同时间尺度的SPEI相关性均比较高,属于气候敏感型林型,在生产经营中要谨慎预防气候变化对该林型带来的伤害;⑤ 森林覆盖度变化与降水和SPEI_24的相关性极显著,长时间尺度的降水变化是影响森林植被覆盖率变化的重要因素之一。     

基于SSA-Mann Kendall的草原露天矿区NDVI时间序列分析

针对煤矿区植被指数时间序列研究中,存在年际尺度上对植被动态规律刻画不全面、月际尺度上因物候性周期波动导致变化趋势和周期振荡信号微弱难以提取、基于变换的变化检测物理意义不够明确的问题,本文以胜利露天矿区为例,在月际尺度,基于SSA-Mann Kendall重建草原露天矿区的采矿扰动区和伪不变特征区MODIS NDVI时间序列的趋势和周期振荡信号,从显著程度和突变时间2方面对趋势成分进行定量化分析,并结合各特征区周期振荡演变特征揭示采矿扰动下草原露天矿区植被生长的动态规律。结果表明：SSA-Mann Kendall能将NDVI时间序列的微弱信号充分放大,便于提取,并可对趋势成分进行定量化表达,结合周期振荡与趋势成分的演变特征有助于辅助识别矿区植被生长的动态特点;伪不变特征区植被无显著下降趋势,采矿扰动区下降趋势显著,且露天采场较排土场的趋势更为明显,草原露天矿区地表植被损伤具有突发性,突变点多发于矿井开工建设时;扰动形式差异导致部分矿井露天采场和排土场周期振荡演变特征存在差异,露天采场植被消失殆尽,排土场因植被恢复措施而具有更复杂的动态特点。     

不同冻结速率对军曹鱼片品质影响的研究

为研究冻结速率对冷冻军曹鱼片品质的影响,以2.08、1.22、0.35cm·h~(-1)三种冻结速率冻结并冻藏于-20±1℃下,观测军曹鱼片理化、质构、感官品质的变化。结果表明:军曹鱼片的冻结点为-1.9±0.2℃;随着冻结速率的增大,贮藏期间军曹鱼片的解冻汁液流失率显著下降(P<0.05),盐溶蛋白的损失率及Ca~(2+)-ATPase活性的损失率显著降低(P<0.05),但干耗变化不显著;军曹鱼片的硬度和耐嚼性随着冻藏时间的延长呈增加趋势,而回复性则下降;不同冻结速率对生、熟鱼片的色泽影响较小,但风味、质地等有显著影响(P<0.05);速冻比慢冻的鱼片更接近于新鲜鱼片,提高冻结速率有利于冻藏军曹鱼片品质的保持。     

咸水体修复过程中含水层物理堵塞试验研究

针对山东半岛大沽河下游咸水体修复过程中含水介质物理堵塞的问题,采用室内模拟试验,系统研究了悬浮物质量浓度和粒径对咸水体含水介质物理堵塞的影响,并通过测定人工回灌过程中渗透系数的时空变化,定量分析和评价含水介质物理堵塞的机理和程度.结果表明:悬浮物质量浓度和粒径是影响含水介质渗透性的关键因素;在悬浮物质量浓度分别为50、100、200 mg·L—1的条件下,含水介质的等效渗透系数分别为其初始值的38％、20％0和10％;随着注入悬浮物质量浓度、注入时间的增加和入渗深度的减小,相对渗透系数不断减小;悬浮物的粒径越小,迁移距离越大,造成渗透系数下降区的厚度越大;随着悬浮物粒径的不断增大,粒径大的颗粒容易被截留在表层,造成表层渗透系数下降幅度增大,其余各层渗透系数下降幅度随深度增加而减小.     

阴影消除植被指数(SEVI)去除地形本影和落影干扰的性能评估与应用

地形校正是崎岖山区遥感图像预处理的关键步骤。为了评估基于DEM数据的经验校正模型、山地辐射传输模型和波段组合优化计算模型在去除地形阴影效应方面的性能,并将其应用于福州市植被覆盖监测,本文采用C模型（和SCS+C模型）、6S+C模型和阴影消除植被指数（SEVI）进行评估、比较。采用1999年和2014年两期Landsat 5 TM卫星数据和相关的 30 m ASTER GDEM V2高程数据,分别计算了C校正（和SCS+C校正）和6S+C校正后的归一化植被指数（NDVI）和比值植被指数（RVI）以及基于表观反射率数据的SEVI。通过目视比较、光谱特征比较以及太阳入射角余弦值（cos i）与植被指数的线性回归分析,可以看出C模型和SCS+C模型对本影具有较好的校正效果,但对落影的校正效果欠佳。NDVI和RVI的本影与邻近无阴影阳坡的相对误差分别从71.64%、52.57%降至4.80%、6.43%（C模型）和0.50%、9.94%（SCS + C模型）,而落影与邻近无阴影阳坡的相对误差分别从62.01%、47.57%降至31.05%、24.40%（C模型）和33.42%、16.01%（SCS + C模型）。在NDVI的落影校正效果上,6S+C模型比C模型和SCS+C模型有一定的提升,本影与邻近无阴影阳坡之间的相对误差为8.63%,落影与邻近无阴影阳坡之间的相对误差为14.27%。而SEVI在消除本影和落影方面整体效果更好,本影和落影与邻近无阴影阳坡的相对误差分别为9.86%和10.53%。最后,基于SEVI对福州市1999-2014年的植被覆盖变化进行了监测。监测结果表明： ① 1999-2014年植被覆盖增加了893.61 km ²,植被增加区域主要分布在海拔250~1250 m范围内;② SEVI均值在坡度40°附近达到峰值。     

Retrieval of Snow Depth on Sea Ice in the Arctic Using the FengYun-3B Microwave Radiation Imager

Snow on sea ice is a sensitive indicator of climate change because it plays an important role regulating surface and near surface air temperatures. Given its high albedo and low thermal conductivity, snow cover is considered a key reason for amplified warming in polar regions. This study focuses on retrieving snow depth on sea ice from brightness temperatures recorded by the Microwave Radiation Imager(MWRI) on board the FengYun(FY)-3 B satellite. After cross calibration with the Advanced Microwave Scanning Radiometer-EOS(AMSR-E) Level 2 A data from January 1 to May 31, 2011, MWRI brightness temperatures were used to calculate sea ice concentrations based on the Arctic Radiation and Turbulence Interaction Study Sea Ice(ASI) algorithm. Snow depths were derived according to the proportional relationship between snow depth and surface scattering at 18.7 and 36.5 GHz. To eliminate the influence of uncertainties in snow grain sizes and sporadic weather effects, seven-day averaged snow depths were calculated. These results were compared with snow depths from two external data sets, the IceBridge ICDIS4 and AMSR-E Level 3 Sea Ice products. The bias and standard deviation of the differences between the MWRI snow depth and IceBridge data were respectively 1.6 and 3.2 cm for a total of 52 comparisons. Differences between MWRI snow depths and AMSR-E Level 3 products showed biases ranging between-1.01 and-0.58 cm, standard deviations from 3.63 to 4.23 cm, and correlation coefficients from 0.61 to 0.79 for the different months.     

Design and realization of the drawing software for snow/ice stratigraphic profile

1　IntroductionSnow/icestratigraphicprofileisoneofthetraditionalandimportantresearchfieldsinglaciology (Qin 1 995 ;Xie 1 988) .Thesnow pitprofilesareobserveddirectlyinthefield ,andthestratigraphicprofilesoficecoresaredelineatedandcompiledindetailat1∶1scalethroughnakedeyesinlow temperaturelaboratory .Themajorstratigraphicchar acteristicsobservedincludingcrystalgrainsize,structureofdepthhoar,lighttransmis sion,meltphenomena,windcrustetc.(ShojiandLangway 1 989) ,arenecessarytobedelineatedindia…     

东北典型林区雪深反演算法的验证与分析

积雪对自然环境和人类活动都有极其重要的影响。积雪参数（雪面积、雪深和雪水当量）反演对水文模型和气候变化研究有着实际的意义。然而,目前森林区的雪深遥感反演精度一直有待于进一步提高。东北地区是我国最大的天然林区和重要的季节性积雪区之一,本文利用FY3B卫星微波成像仪（MWRI）L1级亮温数据和L2级雪水当量数据,以及东北典型林区野外实测雪深数据,对Chang算法、NASA 96算法和FY3B雪深业务化反演算法进行了验证与分析。结果表明：在东北典型林区的雪深反演中,Chang算法和NASA 96算法反演的雪深波动都比较大,当森林覆盖度f≤0.6时,NASA 96算法表现比较好,均方根误差值在3种算法中较小,但当f >0.6时,NASA 96算法失真严重。当考虑纯森林像元（f=1）时,Chang算法低估了雪深47%。当f≤0.3时,FY3B业务化算法始终优于Chang算法。整体上,FY3B业务化算法相对稳定,具有较高的精度。     

Spatial distribution of Ice Shelf Water in front of the Amery Ice Shelf,Antarctica in summer

As a unique low-temperature water mass in Antarctic coastal region, the Ice Shelf Water (ISW) is an important component for the formation of the Antarctic Bottom Water (AABW). In this paper, we present a criterion for ISW identification based on freezing point at the sea surface, and we study spatial distribution of ISW in front of the Amery Ice Shelf (AIS) and its flow path in Prydz Bay by analyzing hydrographic data from Australian cruises in 2001 and 2002, as well as Chinese cruises in 2003, 2005, 2006, and 2008, all being made in the austral summer. The relatively cold and fresh ISW occurred as several discrete water blocks with cold cores in front of the AIS, within the depth range of 100?600 m, under the seasonal thermocline. ISW had obvious temporal and spatial variations and the spatial distribution pattern changed greatly after 2005. Most of ISW was concentrated west of 73°E during 2001 to 2003 and 2006, but it was widespread to east in 2005 and 2008. In all observation years, a small amount of cold ISW always occurs at the west end of the AIS front section, where the coldest ISW in the whole section also occurred in 2001, 2003 and 2006. Considering general cyclonic circulation pattern under the AIS, the ISW flowing out from west end of the AIS front might have experienced the longest cooling period under ice shelf, so it would have the lowest temperature. Analysis of data from meridian sections in Prydz Bay in 2003 implied that ISW in the west could spread north to the continental break along the east flank of the Fram Bank near 70.5°E, mix with the upwelling Circumpolar Deep Water and possibly contribute to the formation of AABW.     

Hydrological character and sea-current structure in the front of Amery Ice Shelf

Hydrological character and Sea-current profiles structure are studied andanalyzed in sea-area of the front of Amery Ice Shelf,Prydz Bay with LADCP,CTDdata.These LADCP,CTD data were acquired during the 19th Chinese Antarctic Sci-entific Expedition.Results of this study agree with that,there exist four differentkinds of water masses in the area of the front of Amery Ice Shelf in the summer of Ant-arctica.Current distribution presents a semi-circumfluence which flows in at the eastand flows out in the west.Moreover,clockwise and anti-clockwise vortices werefound in upper layer and mid-layer in the Prydz Bay.Western areas of these anti-clockwise vortices are positions of inflows from Prydz Bay to Amery Ice Shelf.Thesource of these inflows is the coastal westward current originated in the east of PrydzBay.All these characteristics come down to the pattern of circumfluence,ice meltrate under Ice Shelf,scale of Ice Shelf water production and form of water exchangesbetween area of Ice Shelf and area of Prydz Bay.     

Variations of snow temperature and their influence on snow cover physical parameters in the Western Tianshan Mountains, China

This article discussed about snow temperature variations and their impact on snow cover parameters. Automatic temperature recorders were used to sample at 10-minute intervals at the Tianshan Station for Snow-cover and Avalanche Research, Chinese Academy of Sciences. 10-layer snow temperature and the snow cover parameters were measured by the snow property analyzer (Snow Fork) in its Stable period, Interim period and Snow melting period. Results indicate that the amplitude of the diurnal fluctuation in the temperature during Snow melting period is 1.62 times greater than that during Stable period. Time up to the peak temperature at the snow surface lags behind the peak solar radiation by more than 2.5 hours, and lags behind the peak atmospheric temperature by more than 0.2 hours during all three periods. The optimal fitted function of snow temperature profile becomes more complicated from Stable period to Snow melting period. 22 h temperature profiles in Stable period are the optimal fitted by cubic polynomial equation. In Interim period and Snow melting period, temperature profiles are optimal fitted by exponential equation between sunset and sunrise, and by Fourier function when solar radiation is strong. The vertical gradient in the snow temperature reaches its maximum value at the snow surface for three periods. The peak of this maximum value occurs during Stable period, and is 4.46 times greater than during Interim period. The absolute value of temperature gradient is lower than 0.1°C cm⁻¹ for 30 cm beneath snow surface. Snow temperature and temperature gradient in Stable period∼Interim period indirectly cause increase (decrease) of snow density mainly by increasing (decreasing) permittivity. While it dramatically increases its water content to change its permittivity and snow density in Snow melting period.     

THE LITTLE ICE AGE OF THE NORTHWEST REGION,CHINA

The Little Ice Age began in the early 15 the century and ended in 16 the century in the northwest region of China. In the Northern Hemisphere, the age of the Little Ice Age postponed form north to south, form west to east, and moist region to drought. Judged by the data the Little Ice Age of the Northwest China is later than the eastern China and Europe. The climate of the Little Ice Age in northwest China was cold-wet. In northwest China, as compared with the Little Ice Age, the recently annual temperature have raised about 1-1.3℃, the precipitation have reduced 50-78 mm, the evaporation have increased 7%, the glacier area have reduced about 21-46%, and the runoff have reduced about 14% in the river which the meltwater supply proportion is less than 10%. To sum up, since the Little Ice Age the warm-dry tendency of climatic variation is quite obviously in northwest China. If it goes on like this, its influence will be more severe to the river which meltwater proportion is more than 50%.     

湛江高桥红树林区虾类群落的时空变化

研究2005-2008年广东省湛江市英罗湾高桥3个红树林区(红坎、两头流、西村)虾类群落的变化特征,并分析虾类群落组成与水质指标(盐度,pH)和沉积物指标(pH、可溶性盐、有机质、黏土、粉砂、砂砾)的相关性。结果表明:3个区域捕获虾类13596尾,属3科5属9种,刀额新对虾是高桥虾类的优势种;虾类种类年际变化较大,年间相似度平均为70.4,区域间相似度平均为60.6;红坎虾类多样性较丰富,两头流虾类的优势种明显,各年优势度指数均达0.95以上;3个区域的主要生态因子年间差异不显著(P>0.05);红坎3个采样点的底质性状较复杂,其沉积物特性差异显著(P<0.05),两头流和西村的底质性状较为单一,其沉积物特性均差异不显著(P>0.05)。群落变化特征和沉积物性状有显著相关关系,表明高桥虾类的渔获量受人为因素影响,多样性和分布受环境影响。     

Snow cover variation and streamflow simulation in a snow-fed river basin of the Northwest Himalaya

Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.     

Recreational value of glacier tourism resources: A travel cost analysis for Yulong Snow Mountain

Glaciers, with their unique and spectacular appearances and rich and varied terrain, have received widespread attention and become important tourist attractions. This paper uses the travel cost method to estimate the recreational value of the glacier tourism resources of Yulong Snow Mountain (also called Jade Dragon Snow Mountain), which is the most developed glacier tourist attraction in China. First-hand information was obtained through field surveys, and the travel costs of visitors visiting the Yulong Snow Mountain glacier were calculated before the method was applied to evaluate the recreational value of the focal glacier resource. The results show that the Yulong Snow Mountain consumer surplus associated with its glacier resources in 2016 ranged from 645.59-3439.10 million CNY, and the total recreational value ranged from 1.97-8.17 billion CNY. Approaches allocating travel costs across multiple recreational sites, however, can vary, and there is large difference in estimated results depending on used approaches. Nevertheless, the results of the analysis can help understand the socio-economic value of glacier resources and provide a reference for their development and protection.