洪湖湿地抗渍蓄洪能力分析

鉴于洪湖湿地为渍涝灾害的多发区,并在江汉平原具有一定的代表意义,本文以该区为研究对象,利用遥感和地理信息系统技术进行分析,以便正确认识洪湖湿地的抗渍蓄洪能力.建立洪湖湿地的TIN模型以分析该区的抗渍蓄洪能力,并分别计算出洪湖湖泊的调蓄能力和整个洪湖湿地水位同蓄水面积及蓄水容量之间的关系.通过TIN模型与2001年的LandSat-ETM+遥感图像的叠加分析,统计出不同湿地类型的平均高程.依此计算出23. Ini高程线为水稻田的耕作线,由此推算出水稻基本不受影响条件下洪湖湿地的调蓄容量为1.087×10⁹ m³.并提出在该区建立基于地理信息系统的减灾决策体系的建议,以便进行有效的防灾减灾.     

近60年来白洋淀流域河川径流演变及湿地生态响应

白洋淀是雄安新区的核心生态功能区,近几十年来面临水源不足、湿地萎缩等生态环境问题.选取白洋淀流域上游王快、西大洋及拒马河3个子流域开展河川径流演变研究,结合1969年以来18期白洋淀湿地遥感影像,揭示白洋淀流域河川径流驱动湿地演变的过程机制.结果表明：近60年来白洋淀流域山区径流量呈持续衰减趋势,从P1阶段（1961—1979年）至P3阶段（1997—2019年）,典型子流域年径流系数均值由0.29降至0.12,山区年径流总量由30.84×10⁸ m³/a降至11.37×10⁸ m³/a,降幅达63.1%,梯田修建、地下水开采等人类活动是导致径流衰减的主要原因;不同子流域产流和基流减少对径流衰减的贡献率存在差异,以变质岩为主的王快子流域径流衰减的主要原因是地表产流减少,碳酸盐岩分布较广的拒马河子流域径流衰减的主要原因是基流减少;白洋淀湿地面积变化受控于地表水位波动,近60年来白洋淀湿地退化的直接原因是入淀流量减少,根本原因是人类活动影响导致的山区径流衰减.     

鄱阳湖自然保护区植被生物量时空变化及水位影响

基于时间序列Moderate Resolution Imaging Spectroradiometer(MODIS)植被指数,结合野外实测生物量及水文气象等数据,分析了2001 2010年退水期鄱阳湖国家自然保护区湿地植被生物量的空间格局及其时间变化规律,并在此基础上探讨了水位变化的影响.研究结果表明:(1)湿地植被生物量密度多年均值处于0~1402 g/m²之间,除蚌湖四周生物量沿湖心向四周逐渐升高外,其他区域呈现南高北低的分布格局,且其分布与研究区高程密切相关;(2)湿地植被生物量密度多年均值在退水初期为901 g/m²,随时间变化先上升后降低;植被分布面积则随着滩地出露而逐渐增大,随后基本稳定;总生物量呈现单峰变化,在11月初达到最高值.2001 2010年研究区年均生物量变化呈现波动状态,多年均值为18.3×10⁷kg;最高出现在2006年,达到28.2×10⁷kg,2010年最低,仅有8.37×10⁷kg;(3)年均生物量与洲滩出露天数以及植被分布面积呈显著正相关,相关系数分别为0.719和0.865.水位变化为湿地生物量变化的重要影响因素.     

亚高山湿地摇蚊亚化石记录的近两百年来环境演化——以重庆葱坪湿地为例

偏远的亚高山湿地受人为活动直接干扰较小,是追踪气候变化和大气沉降双重影响下湿地生态系统演化的理想研究地.本研究以位于巫山的葱坪湿地为研究对象,基于一根50 cm沉积岩芯的²¹⁰Pb和¹³⁷Cs测年、摇蚊亚化石和元素序列,探讨该湿地近200年来环境演化历史.结果表明,摇蚊种群由1910年之前的Chironomus anthracinus-type、Limnophyes sp.、Cladotanytarsus mancus-type 1变为1910-1925年的C.mancus-type 1、C.anthracinus-type、Procladius sp.和Endochironomus impar-type的优势组合,这些优势种均指示浅水环境.此后,耐营养种E.impar-type、Polypedilum nubeculosum-type和C.anthracinus-type逐渐成为优势种.冗余分析表明,总磷、总碳和钙是解释摇蚊组合变化的显著环境因子.20世纪30年代以前摇蚊种群可能与进入湿地的径流量小、水位较低相关,而20世纪中叶以来摇蚊组合变化指示大气沉降增长背景下湿地营养富集过程.在大气沉降和气候变化的双重影响下,耐营养属种增加和生物多样性降低表明葱坪湿地生态环境正发生退化.     

入湖河口湿地四种植物群落类型的土壤氮素空间分布特征

对江苏省溧阳市大溪水库的洙漕河河口湿地中香蒲、水蓼、灯心草和芦苇四种植物生物量、氮含量及植物群落的土壤氮素分布特征进行研究,结果表明:四种植物地上生物量、地上组织氮含量、地下生物量、地下组织氮含量存在显著差异;土壤烧失量(LOI)、总氮(TN)、硝态氮(NO₃^--N)在垂直分布上表现为由表层向下减少的总体分布趋势,铵态氮(NH₄⁺-N)浓度的剖面变化呈现先减少后增加的趋势;四种植物群落土壤氮浓度各不同,但均大于对照,以有机氮为主,说明湿地具有一定的储氮能力;不同的植物群落影响湿地氮素的分布.相关性分析显示,土壤LOI与TN、NO₃^--N和NH₄⁺-N均存在极显著相关性,无机氮构成比例较小,仅为1.41%,表明土壤中的氮素主要以有机氮的形式存在;土壤氮浓度与植物生物量及组织氮含量相关性不大,说明土壤氮形态浓度不仅受到植物生长的影响,同时也可能受到植物根区环境、微生物数量与活性等的影响.     

鄱阳湖湿地3种优势植物枯落物分解过程及碳氮同位素分异特征

植物枯落物分解是维持湿地生态系统能量流动、物质循环和养分平衡的关键生态过程。于2017年11月-2018年4月在鄱阳湖湿地开展野外原位分解实验。利用分解袋法对3种优势植物芦苇(Phragmites australis)、南荻(Triarrhena lutarioriparia)和薹草(Carex cinerascens)枯落物纤维素和木质素分解过程和δ¹³C、δ¹⁵N分异特征开展了模拟实验研究。结果表明: 芦苇、南荻和薹草枯落物的纤维素和木质素的分解速率、干物质残留率以及δ¹³C、δ¹⁵N差异性极显著,造成这种差异的主要原因是不同种类植物枯落初始化学特性的不同,尤其是C/N和木质素/N的不同。枯落物中纤维素和木质素的分解速率都表现芦苇最大,薹草次之,南荻最小。Olson负指数衰减模型能非常好地模拟和预测3种植物枯落物的分解过程。伴随分解过程,3种植物枯落物δ¹³C上下波动,总体上呈显著降低的趋势,而δ¹⁵N则都呈现波动性的略有升高趋势,这说明在枯落物分解过程的不同阶段内,受枯落物基质质量和微生物代谢活动的双重影响,¹³C与¹⁵N既有释放也有富集。δ¹³C与枯落物纤维素和木质素分解速率都有极显著的正相关关系。δ¹⁵N与分解速率相关性不显著,这说明除了氮元素的迁移转化外,还有其他因素影响δ¹⁵N的变化。本研究有助于加深枯落物分解过程中基质质量调控机制的认识,深化对鄱阳湖湿地生物地球化学循环过程的科学理解。     

基于无人机和卫星遥感影像的升金湖草滩植被地上生物量反演

湿地植被地上生物量是衡量湿地生态系统健康状况的重要指标,对于珍稀水禽越冬繁殖、全球碳循环、生态净化具有重要意义,是生态学与遥感解译的研究热点之一.针对于地上生物量的测算,卫星遥感数据覆盖范围广但其空间分辨率较低,无人机遥感数据空间分辨率高但采集范围小,同时受湿地面积、观测系统及外界环境等条件的影响,使得遥感影像地上生物量反演更加复杂和困难.本研究基于无人机和高分一号数据对升金湖草滩植被地上生物量反演进行研究,结合升金湖保护区4个样区无人机可见光影像与相应样区实测样本数据,建立地上生物量与可见光波段、多种可见光植被指数的线性、幂函数、多项式、对数回归模型,并通过可决系数（R²）、平均绝对误差（MAE）和均方根误差（RMSE）对模型进行精度评价,选择最优模型对无人机影像进行地上生物量反演;通过可见光波段反演得到的生物量,与高分一号WFV归一化差分植被指数（Normalized Difference Vegetation Index,NDVI）影像相结合进行回归建模,获取整个升金湖草滩植被地上生物量分布.结果表明,利用无人机红光波段建立的多项式方程对地上生物量反演有着最高模拟精度,R²=0.86、预测精度MAE=111.33 g/m²、RMSE=145.42 g/m²,且红光波段生物量反演方法得到的结果与实际生物量分布一致性较高,高分一号WFV NDVI与无人机反演生物量构建的多项式模型为最优模型,R²为0.91.本研究利用无人机和高分一号数据进行生物量反演研究,整合多源遥感数据优点,以获取更加丰富和准确的信息,进而提高地上生物量反演精度,为湿地监测和湿地恢复管理提供数据和技术支撑,具有重要研究意义和应用价值.     

鄱阳湖湿地溶解性有机质的光化学属性对水体光活性中间体(PPRIs)季节性变化的影响

湿地的水文和水化学在时空尺度上会呈现显著差异,进而会引发光化学反应的变化,光活性中间体(PPRIs)是水体间接光反应的产物,具有极强的氧化性,对水环境中有机物和污染物的归驱具有重要的影响,因此迫切需要探究湿地中PPRIs的产生过程。本研究通过捕获剂法监测了鄱阳湖湿地4个季节水体中3种PPRIs(¹O₂、·OH及³CDOM^*)的产生速率和稳态浓度的变化,并通过紫外吸收光谱、三维荧光光谱、以及傅立叶变换离子回旋共振质谱等技术对水体中可溶性有机质(DOM)组分的化学特征进行分析,揭示了鄱阳湖湿地不同季节水体中的DOM的光化学反应特性及与PPRIs产生的相关性。结果发现:鄱阳湖夏季和秋季水体的pH值、溶解有机碳(DOC)浓度较高,相反,硝酸盐、亚硝酸盐浓度在夏季和秋季较低。夏季和秋季的DOM中芳香族化合物丰度较高,并且木质素丰度明显高于冬季和春季。不同季节鄱阳湖水体有色可溶性有机物产生能力依次为秋季>夏季>冬季>春季。夏季和秋季水体中¹O₂和·OH产生速率和稳态浓度显著高于春季和冬季水体。pH、DOC、E2/E3、脂类、蛋白类及木质素类与PPRIs产生速率展现出了良好的正相关关系,尤其是其中的DOC与木质素类组分;另外在三维荧光指标结果中,荧光指数(FI)和新鲜度指数(β/α)与PPRIs呈现负相关关系,证明FI值越低即DOM陆源性越高、非新生DOM比例越高,则PPRIs产生速率越高。综上,PPRIs的光化学产生与植物源DOM密切相关。与春季和冬季相比,夏季和秋季鄱阳湖水体的有机质高,而其中DOM组分中芳香族化合物丰度较高,主要来自陆生植物和土壤有机质,其有机质的腐殖化水平较高,而在春季和冬季水体有机质主要来自湖泊本身和微生物产生的有机质,属于内源。淹水植物残体降解过程释放的有机组分,对夏、秋季DOM的来源和组成有着极易被忽视的影响和作用,而其中光化学活性较强的有机组分如木质素是造成其PPRIs产率更高的主要原因。     

鄱阳湖典型洲滩湿地植物水碳稳定同位素与内在水分利用效率变化特征

在极端水文事件频发和人类活动影响加剧的背景下,鄱阳湖水文情势的异常变动给洲滩湿地植物带来了一系列影响。为进一步了解鄱阳湖湿地植物水分利用来源和内在水分利用效率(iWUE)的季节变化规律,揭示优势植物在生长过程中对不同水分变化的适应策略,于2020年12月-2021年5月在鄱阳湖国家级自然保护区蚌湖和修河之间的典型洲滩湿地上设置监测断面,对灰化苔草(Carex cinerascens)、南荻(Triarrhena lutarioriparia)植物样品及其潜在水源样品进行系统采集,测定并分析了水、碳稳定同位素的动态变化特征和指示意义。结果表明,典型洲滩湿地苔草和南荻植物茎水的氢、氧稳定同位素组成没有表现出明显差异,从冬季至春季,植物茎水的δ¹⁸O值总体上均呈现波动富集的变化趋势。苔草在春季生长期iWUE没有表现出明显变化,而南荻在萌发时期iWUE最低,之后的生长期iWUE具有显著的增长趋势。在各潜在水源当中,植物茎水的同位素组成与土层中的重力水最为相近,其次为与根系分布联系密切的土壤水。在春季降水频繁时,来源于降水且埋深较浅的重力水可能是植物利用的主要水源,而在枯水期重力水埋深较深时,植物采取降水和土壤水的混合利用模式应对水分胁迫。植物叶片有机质的δ¹⁸O值分析发现,苔草在萌发生长期iWUE的变化与光合作用能力相关的因素有关,南荻iWUE的变化主要受气孔导度变化的影响。     

新疆艾比湖主要入湖河流同位素及水化学特征的季节变化

通过野外调查取样和室内测试分析,利用水文化学以及氢氧稳定同位素技术,分析艾比湖主要入湖河流氢氧同位素及水化学的组成特征,并探讨其季节性变化.结果表明：地表水水质指标高值多出现于博乐市、温泉市和精河县及艾比湖湿地附近,主要污染为水体富营养化、工矿业污染以及有机质污染,其污染程度夏、秋季高于春、冬季.河水的δ¹⁸O与δ²H存在明显的线性关系,其相关指数为夏季（R²=0.99） > 春季（R²=0.98） > 秋季（R²=0.96） > 冬季（R²=0.90）,均沿当地大气降水线分布,受西北干旱区强烈的蒸发作用影响,各季节河流斜率均小于8,氘过量参数值多为正值.博尔塔拉河与精河地表水体δ¹⁸O值整体上表现为沿流程逐渐偏正的趋势,博尔塔拉河水体氢氧同位素与高程相关指数表现为春季（R²=0.70） > 冬季（R²=0.57） > 夏季（R²=0.45） > 秋季（R²=0.30）,精河因其海拔差异不大,流程简短,与高程相关性低.博尔塔拉河和精河氢氧同位素与氯化物、硫酸盐、五日生物需氧量等指标间存在相关性,且在夏、秋季最大,相关系数R>0.75,与总磷、Cu²⁺、色度、浊度等指标基本都不显著相关,相关系数R<0.25.     

Infiltration-excess caused by Stemflow in a cyclone-prone tropical rainforest

Tropical rainforest canopy trees that have large projected areas of upwardly inclined branches are capable of funnelling large volumes of rainwater down their trunks. During periods of prolonged heavy rainfall on Mount Bellenden Ker in northeast Queensland, Australia, stemflow volumes were found to be as much as two orders of magnitude greater than the volume of incident rainfall expected in a rain gauge occupying an area equal to the trunk basal area. Stemflow totals ranging from 6000 to 70000 litres were generated by individual trees from 7800 mm of rainfall over two successive wet seasons. The combination of high intensity rainfall and the funnelling effect results in significant quantities of infiltration-excess at the ground surface. Stemflow fluxes as high as 31.4 cm³ min^?1 per cm² of basal area (i.e. the equivalent of 314 mm min^?1) were recorded when rainfall intensity was only 2 mm min^?1. The mean infiltration capacity of the topsoil was determined to be 6.2 mm min^?1. The areas over which the stemflow would have had to spread in order to infiltrate were computed to be as much as 3 m² around the bases of individual canopy trees. Approximations of the distances that the infiltration-excess would have travelled away from the tree bases were calculated by assuming that the infiltration area either expands radially outward in the form of an annulus or extends straight downslope from the tree base.     

基于Landsat影像的近40年来(1982—2021年)三峡库区水面面积及其蒸发损失变化

三峡水库蓄水引起库区水位抬升,水面面积显著增加,对区域水文循环过程产生了一定影响。为揭示三峡水库蓄水前后水面面积及蒸发损失变化规律,选取三峡库区坝前至寸滩区间作为研究区,利用Landsat影像数据提取1982—2021年水面面积,分区建立水位与面积关系曲线,进而推求库区逐日水面面积。在估计三峡库区水面面积的基础上,结合站点潜在蒸发资料推求水面蒸发损失量。研究结果表明:2010年三峡水库全面运行后,坝前至寸滩库区平均水面面积由蓄水前的372.96km²,增加到761.31km²,较蓄水前增加了1.04倍。同时,三峡水库的蓄泄调节改变了库区河段原有的水文节律,使得库区水面面积的季节性变化特征较蓄水前发生了显著变化。蓄水后,冬季水面面积最大,平均为843.81km²,较蓄水前增加了1.89倍;秋季、春季次之,水面面积分别为818.73和735.28km²,较蓄水前分别增加了97.17%和1.28倍;夏季水面面积最小,为653.03km²,较蓄水前仅增加了39.06%。水库全面运行后,...     

近40 a西藏那曲当惹雍错湖泊面积变化遥感分析

西藏著名圣湖之一的当惹雍错,是藏北高原腹地内陆封闭大湖,对湖泊面积变化的长时间序列研究较少,本文通过高分辨率陆地资源卫星Landsat TM/ETM+数据源,利用遥感和地理信息系统软件,通过人工目视解译方法对1977-2014年当惹雍错湖泊面积变化进行系统分析,并结合流域临近气象站资料,流域冰川等辅助数据对其湖泊面积变化原因进行综合分析.结果表明,1977-2014年当惹雍错湖泊平均面积为835.75 km~2,1977-2014年湖泊面积总体呈上升趋势,1970s湖泊平均面积为829.15 km~2,1980s和1990s湖泊平均面积分别为827.50和826.42 km~2,2000年之后湖泊面积明显增加,2000s湖泊平均面积与1970s相比,增幅为8.04 km~2.当惹雍错湖泊空间变化特点是,位于最大河流入口处达尔果藏布的湖泊东南部扩大明显,湖泊西南部小湖1于2014年9月开始明显扩大并与当惹雍错有相连趋势;流域冰川融水是当惹雍错主要补给源,近40 a当惹雍错湖泊面积变化是在气温升高的背景下,冰川、降水量和蒸发量三者共同变化作用的结果.     

帕隆藏布流域冰湖变化及危险性评估

冰湖作为区域气候变化的灵敏指示器和主要冰川灾害的启动器,认识其空间分布及变化特征对探讨冰湖对气候变化的响应规律及冰湖溃决危险性评估具有重要意义.基于1968-1980年地形图数据和1994-2016年Landsat TM/OLI遥感影像资料,综合利用RS、GIS技术和数理统计方法分析帕隆藏布流域面积≥ 0.01 km²冰湖时空分布及其动态变化,并对潜在危险性冰湖进行判别和评估.结果表明：2016年帕隆藏布流域共有冰湖351个,面积50.48 km²,且面积和数量分别以面积>1 km²和面积<0.1 km²的冰湖为主,这些冰湖主要分布于海拔2800~5400 m之间.近50年来帕隆藏布流域冰湖总体呈数量增多、面积增加态势;海拔<3000 m的冰湖相对稳定,而海拔>4500 m的冰湖数量和面积增加则相对迅速.近50年间帕隆藏布流域冰川面积减少591.34 km²,气候变暖导致的冰川末端退缩和冰川融水增加为冰湖形成和扩张提供了发育空间和物质来源.切毛措、光谢错等9个冰湖为潜在危险性冰湖,预计未来一段时间内帕隆藏布流域冰湖溃决可能处于活跃阶段,其形成和暴发也将更加频繁.     

Observations of contemporary arroyo cutting near Santa Fe,New Mexico,U.S.A.

Arroyo cutting that began in the American Southwest in the 1880s is associated with sudden runoff, a circumstance characteristic of this semiarid region in which occasional intense rainfall exceeds the capacity of the ground to absorb water. This report describes two arroyos in an area of moderately dissected bolson deposits southwest of Santa Fe, Cañada de la Cueva and Pueblo Cañon, where arroyo cutting since 1970 has been closely related to runoff from summer rain. The area is vegetated chiefly by grama grass and scattered juniper. Cutting is monitored by repeated surveys of channel floors, cross-sections, and headcuts, and by repeated photographs taken as stereopairs. Rainfall and discharge are measured simultaneously in 5-minute intervals by dual digital recorders at a gauging station on Cañada de la Cueva (drainage area 4.64 km²). Discharge has been as much as 18.2 m³/s from rainfall of 25.2 mm. The maximum 15-minute intensity for this storm was 64.0 mm/hr, and runoff was 7.9 mm. The flood peak arrived in 20 minutes, by which time 80 per cent of the rain had fallen, and the flow subsided to a tenth of its maximum in less than an hour. This storm at Pueblo Cañon (drainage area 13.3 km² above the place of measurement) resulted in an estimated discharge of 140 m³/s, and features produced by hail on the channel floor suggest that the duration of flow could have been as brief as 30 minutes. Observed increments of headward cutting at Cañada de la Cueva range from 0.28 m for 1.8 mm of runoff to 4.9 m for 12 mm of runoff. Aggregate cutting in 5 years has been as much as 13.7 m, resulting in erosion of 570 m³ of alluvium. Headward cutting near the mouth of Pueblo Cañon has been observed in increments of 10.3, 14.6, and 20.7 m, for an aggregate of 45.6 m, as measured from 1971 to 1974. This cutting removed 1,770 m³ of alluvium.     

Spatial distribution analysis of landslides triggered by the 2013-04-20 Lushan earthquake,China

The 2013-04-20 Lushan earthquake(seismic magnitude Ms 7.0 according to the State Seismological Bureau)induced a large number of landslides.In this study,spatial characteristics of landslides are developed by interpreting digital aerial photography data.Seven towns near the epicenter,with an area of about 11.11 km2,were severely affected by the earthquake,and 703 landslides were identified from April 24,2013 aerial photography data over an area of 1.185 km2.About 55.56% of the landslide area was less than 1000 m2,whereas about 3.23 % was more than 10,000 m2.Rock falls and shallow landslides were the most commonly observed types in the study area,and were primarily located in the center of Lushan County.Most landslide areas were widely distributed near river channels and along roads.Five main factors were chosen to study the distribution characteristics of landslides:elevation,slope gradients,fault,geologic unit and river system.The spatial distribution of coseismal landslides is studied statistically using both landslide point density(LPD),defined as the number of landslides(LS Number)per square kilometer,and landslide area density(LAD),interpreted as the percentage of landslides area affected by earthquake.The results show that both LPD and LAD have strong positive correlations with five main factors.Most landslides occurred in the gradient range of 40°-50° and an elevation range of 1.0-1.5 km above sea level.Statistical results also indicate that landslides were mainly formed in soft rocks such as mudstone and sandstone,and concentrated in IX intensity areas.     

Abiotic Stream Classification as a Basis for a Surveillance Monitoring Network in Austria in Accordance with the EU Water Framework Directive

This study presents the 26 major surface water types established in Austria in accordance with the draft of the EU Water Framework Directive (WFD). These types are made up of so‐called aquatic landscape units and large rivers. The 17 aquatic landscape units were defined using a database in which all Austrian running waters with a catchment area greater than 10 km^[2] were described according to the following typological features: size of catchment area, altitude of catchment area and confluences, stream order, geology, zoogeographical regions (ecoregions), and subregions. At running waters with gauges, a classification according to flow regimes was carried out. Large rivers were defined as running waters with a stream order ⩾7 and/or a catchment area > 2500 km² and/or with an average flow >50 m³/s. These major types represent, inter alia, the basis for the establishment of a surveillance monitoring network as required by the WFD.     

ESTIMATES OF TERRESTRIAL THERMAL GRADIENTS AND HEAT FLOW VARIATIONS WITH DEPTH IN THE HINTON-EDSON AREA OF THE ALBERTA BASIN DERIVED FROM PETROLEUM BOTTOM-HOLE TEMPERATURE DATA*

There is a significant increase in terrestrial heat flow with depth in the Hinton-Edson area of the deep part of the western Canadian sedimentary basin in Alberta. This is especially true near the Rocky Mountain foothills which is an area of high relief, high hydraulic head and regional water recharge. Gravity-imposed downward movement of meteoric water through the thick sedimentary strata with velocities as low as 10^–10 m/s to 0.5 × 10^–9 m/s may cause an increase of heat flow with depth. Such disturbance of heat flow with depth on a regional scale in the sedimentary strata means that it is not possible to determine the background conductive steady-state heat flow associated with crustal or upper mantle heat sources in such an area from measurement of conductive heat flow in the part of the sedimentary column where water movement occurs. This is because the convective portion cannot be determined, particularly when measurements are made in only part of the regional hydrodynamic system of the basin.     

近40年青藏高原湖泊面积变化遥感分析

以MSS、TM和ETM遥感影像作为主要信息源,综合利用RS、GIS技术,提取青藏高原1970s、1990s、2000s及2010s 4个时段的湖泊面积信息,分别从区域位置、面积规模、海拔高度3方面分析其近40年来的变化趋势及变化特征,同时结合1972-2011年间青藏高原气候变化情况,初步探讨了影响青藏高原湖泊面积变化的主要原因.研究结果表明:(1)青藏高原面积大于10 km²的湖泊有417个,这些湖泊大多是面积为10~100 km²的小型湖泊,空间上集中分布在高原西部地区,海拔上集中在4500~5000 m范围内;(2)近40年青藏高原湖泊面积的变化趋势及差异性特征在整体上表现为湖泊呈加速扩张的趋势,其中2000s-2010s时段是湖泊扩张最显著的时期;在区域位置上,北部地区的湖泊变化最为剧烈;在面积规模上,小型湖泊扩张最为显著;在海拔高度上,低海拔地区湖泊扩张剧烈;(3)近40年青藏高原气候暖湿化程度明显,气候变化对湖泊面积变化影响显著;在气象要素中,降水量的变化是青藏高原湖泊面积变化的主要驱动因子.     

Rating Water Quality in Sevastopol Bay by the Fluxes of Pollutant Deposition in Bottom Sediments

Sevastopol Bay is used as an example for the development of criteria for rating anthropogenic impact by elimination fluxes from the water area of post-Chernobyl (⁹⁰Sr, ¹³⁷Cs, ^239,240Pu) and natural (²¹⁰Pо) radionuclides, as well as mercury and organochlorine compounds. The differentiation of the bay water area into zones with different biogeochemical conditions and the balance approach to interpreting field observation data were used to assess the conditioning capacity of Sevastopol Bay ecosystem for conservative radioactive and chemical substances by elimination fluxes of pollutants into aqueous depot, which is the open part of the Black Sea and into the geological depot, i.e., its bottom sediment stratum.