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1.
东太湖水温变化与水-沉积物界面热通量初探 总被引：1，自引：0，他引：1
水温对沉水植被的生长和分布具有重要作用，水-沉积物界面热通量对浅水湖泊水温变化的影响值得关注.东太湖是我国东部典型的草型浅水湖区，采用自2013年11月至2015年10月对东太湖湖心进行的不同深度水体及沉积物温度高频观测数据，结合东太湖表层沉积物的热力学性质计算了水-沉积物界面热通量，分析了东太湖水温和水-沉积物界面热通量的变化特征并探讨了其影响因素.结果表明：东太湖各深度水体日升温过程随水深增加后延，升温过程夏季延长，冬季缩短；表层水温日变幅最大，底层水温日变幅次之，沉积物温度日变幅最小，各深度温度日变幅夏季最小、冬季最大；春季和夏季升温过程中各深度日均温变化沿水深存在约1天的延迟，秋季和冬季无此现象；2015年与2014年东太湖温度变化趋势相同，同比月均温差与气温差呈线性相关.沉积物8：00-19：00向水体放热增加或从水体吸热减少，19：00至次日8：00放热减少或吸热增加；3-9月从水体吸热，为热汇，10月至次年2月向水体放热，为热源，沉积物全年为湖泊热源；逐日水-沉积物界面热通量每月6至15日存在相对年变幅较小幅度的正弦式波动.水温和水-沉积物界面热通量的变化主要受太阳辐射和气温的影响，二者对气象参数的响应具有迟滞现象；水-沉积物界面热通量与水温呈负相关，其变化相对水温迟滞，水-沉积物界面热交换的主要作用为缓冲湖泊水体的热量变化；夏季，沉水植物能降低湖泊各层水温和垂向水温差. 相似文献
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西南峡谷型水库的季节性分层与水质的突发性恶化 总被引：40，自引：3，他引：37
选择西南云贵高原乌江流域的百花湖水库进行了气象、水温度和水化学(DO、FeⅡ和MnⅡ)的连续监测(13个月).结果表明,由于气候等原因,百花湖水库的水体在夏季形成分层,但是没有典型分层湖泊的温跃层变化,这种水体温度结构可以在4-10月保持稳定;这种"不显著的"温度分层结构,有效限制了上下水团的混合,形成显著的水体溶解氧分层,氧化/还原界面可达到水深8m左右.20世纪90年代初以来,贵州多座水库频繁出现的季节性水质恶化现象,与水库水体混合期(多为夏末初秋),水体分层结构失稳有关.上下层水体的垂直交替,使下层水体中的还原性物质带入上层湖水,造成表层水体缺氧和表观浑浊,鱼类窒息死亡.在百花湖水库的研究表明,西南地区深水水库,可以在夏季出现一定的水体温度分层结构,并导致显著的水体水化学(如溶解氧)分层,进而影响水库水环境质量. 相似文献
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新安江水库(千岛湖)湖泊区夏季热分层期间垂向理化及浮游植物特征 总被引：20，自引：8，他引：12
2010年7月对亚热带特大型水库——新安江水库湖泊区水体的垂向物理、化学参数以及浮游植物群落进行了观测研究,并应用Water-PAM对水体浮游植物垂向光合作用参数进行了测定.研究结果表明:夏季该水库湖泊区在水下10～20 m处形成明显的温跃层,垂向pH值、溶解氧及浊度的变化同叶绿素a浓度呈现高度一致;夏季浮游植物群落以硅藻占绝对优势,水体表层以梅尼小环藻(Cyclotella meneghiniana)为主,表层以下其它各层均以巴豆叶脆杆藻(Fragilaria cro-tonensis)为绝对优势种,垂向分布表现为5～10 m区间为浮游植物高密度区域,温跃层以下浮游植物密度显著下降,水温分层可能是决定浮游植物垂向分布的重要因素之一.浮游植物最大光合效率从表层向下层逐步降低,实际光合效率最大值出现在垂向10 m区域. 相似文献
4.
-座富营养化水库—福建山仔水库夏季热分层期间浮游植物垂向分布 总被引：10，自引：2，他引：8
对福建省水温分层型富营养化山仔水库夏季大坝断面垂向水体的物理化学参数进行了监测分析,并应用荧光分析法结合显微镜细胞计数法,对垂向分层水体和沉积物中的浮游植物生物量、群落组成及丰度进行了分析.结果表明,水库的水温分层能够引起水化学指标的分层.夏季大坝断面水体中的浮游植物以蓝藻门微囊藻属占绝对优势,垂向分布表现为表层的浮游植物细胞数量高于底层,温跃层以下细胞数急剧减少,水温分层可能决定着浮游植物的垂向分布,底泥中的浮游植物将为水体的水华提供"种源". 相似文献
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6.
天目湖沙河水库溶解氧分层的季节变化及其对水环境影响的模拟 总被引：4，自引：1，他引：3
溶解氧(DO)是水体能否维持生态平衡的重要指标,是湖泊初级生产力与水动力条件的综合反映.研究DO及其分层的季节变化对认识湖库的富营养化过程有重要意义.本研究以天目湖沙河水库为例,运用西澳大学开发的三维水动力水质模型——ELCOM-CAEDYM对天目湖的水温、DO和总磷(TP)进行了为期1年的数值模拟.结果表明,模型较好地模拟出了水体温度和DO分层过程以及TP的时空分布,3个指标在水体表层、中层和底层的模拟值与实测值拟合良好,均方根误差分别在1.8℃、1.8 mg/L和0.003 mg/L以内,Nash-Sutcliffe有效性系数均在0.7以上,相对误差均低于10%.沙河水库不同季节的DO垂向分层与温跃层协同变化:冬季垂向混合;春季(4月)温跃层开始发育,底部出现氧不足;夏季(7月)温跃层位于4~10 m之间,同时底部低氧区(DO<2 mg/L)面积达35%;秋季(9月末)低氧区随着温跃层的消失而消失;冬季再次垂向混合.全湖DO和TP的时空分布表明,南半库区磷的来源主要是外源输入,而北半库区磷的来源主要是由水体底部低氧导致的磷内源释放.DO季节分层还有可能通过影响藻类活动而对水环境造成影响. 相似文献
7.
福建山仔水库不同季节表层沉积物内源磷负荷分析 总被引：4，自引：0，他引：4
对山仔水库沉积物各形态磷的季节性特征以及夏、冬季磷释放速率进行研究.结果表明,该水库表层沉积物含有较丰富的磷,4个季节各采样点表层沉积物总磷含量范围为(521.23±7.60)~(1255.54±11.03)μg/g,夏季各采样断面中总磷含量及各形态磷含量均高于其他季节.表层沉积物磷以无机磷为主,且主要赋存形态为铁/铝结合态磷.活性较大的铁/铝结合态磷和有机磷占总磷量的77%~90%.柱状样模拟实验结果表明:夏季溶解性磷释放平均速率范围在1.66~2.49 mg/(m2·d),冬季溶解性磷释放平均速率范围为0.69~1.29 mg/(m2·d),夏季各采样点表层沉积物磷释放速率约为冬季的2倍.由于水温分层,夏季沉积物释放的溶解性磷主要滞留在上覆层,但夏季暴雨天气可能导致水温分层破坏,沉积物释放的溶解性磷对水体将产生重要影响;冬季由于水温分层破坏导致上、下水层混合,沉积物释放的溶解性磷被带到上层,对上覆水体水质的影响不容忽视. 相似文献
8.
为更好地研究贵州红枫湖的水质变化情况，本文利用贵阳市两湖一库环境保护监测站2009-2018年对红枫湖7个代表性监测点的营养盐、叶绿素a（Chl.a）浓度和水温、气温、透明度、降雨量等水文气象条件逐月监测数据，分析红枫湖10年间水体营养盐和Chl.a浓度以及部分水文气象条件的变化趋势.运用综合营养状态指数（TLI）对红枫湖营养状态进行评价，采用Pearson相关系数法统计分析10年内Chl.a浓度与总磷（TP）、总氮（TN）等水化学组成及水位、气温等水文气象条件的相关性.结果表明，2009-2018年红枫湖水体逐月TN浓度有较大波动（0.56~2.80 mg/L），春、夏季高于秋、冬季；水体逐月TP浓度为0.016~0.103 mg/L，夏季略高于冬季；逐月氨氮（NH3-N）浓度为0.007~0.71 mg/L，春季 > 冬季 > 秋季 > 夏季；水体逐月Chl.a浓度呈季节性波动（0.8~38.9 mg/m3），夏季 > 春季 > 秋季 > 冬季，年内先上升后下降.TP、NH3-N、Chl.a浓度整体呈下降趋势，10年间水质有很大改善.经计算红枫湖在这10年间处于中营养状态至轻度富营养状态，且营养状态指数呈逐年下降趋势，夏季TLI明显高于其他季节.统计分析表明，红枫湖水体Chl.a浓度与高锰酸盐指数、NH3-N、TP浓度均呈显著正相关，与氮磷比呈显著负相关，与水温、pH、降雨量、气温、日照时数呈显著正相关，与透明度、气压呈显著负相关，与水位、湿度、风速无显著相关关系.表明这10年来红枫湖水体Chl.a浓度不仅受营养盐浓度控制，很大程度上还受控于气象和水文条件. 相似文献
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稳定分层的深水水库常在冬季发生“翻库”现象,继而导致水库的整体水质下降,影响饮用水安全问题。为探究南方水库热分层消亡时期水体混合特征,在冬季2019年11月—2020年2月对南宁市天雹水库水体理化指标开展长序列原位监测,并结合水体垂直扩散系数,分时期(热分层期、减弱期、完全混合期、形成期)刻画水库热分层消亡全过程中水温T、溶解氧DO的剖面变化特征,探讨了气象因子(气温、太阳辐射、风速等)与水动力因子(水体垂直扩散系数Kz)对水体理化指标的影响。结果显示:桉树人工林区水库热分层消亡期温度分层与溶解氧分层变化不同步,溶解氧分层的破坏较水温分层的破坏出现滞后,其结构失稳是气温及太阳辐射共同作用的结果;期间水体垂直扩散系数变化范围0.16～380.36 m2/d,均值为30.46 m2/d,表层Kz变化的主要控制因子为气温变化,且较T及DO而言,表层Kz对气温的变化更加敏感(RKz=-0.44,RT=0.25,R 相似文献
10.
南海西沙海槽末次冰期以来浮游有孔虫与表层水温 总被引：5，自引：0，他引：5
对南海西沙海槽SA12-19柱状样进行高分辨率的浮游有孔虫和氧碳同位素分析, 并进行14C测年. 结果表明它包含了氧同位素1～3期(第3期不全), 即晚冰期～冰后期的沉积. 对浮游有孔虫定量分析结果, 采用古生态转换函数FP-12E计算各样品所代表的表层海水古温度. 结果表明, 氧同位素1～3期, 本区温跃层有增大的趋势, 尤其在中全新世出现温跃层短暂加深的现象. 表层海水温度全新世冬季23.3～27.2℃, 夏季28.8～29.8℃; 氧同位素2期冬季21.4～24.4℃, 夏季28.1～29.0℃; 氧同位素3期冬季表层水温为21.9～25.2℃, 夏季为28.5～29.3℃. 氧同位素2期冬季表层水温比1期低2~ 6℃. 在冰期向冰后期过渡中出现明显温度回返的“新仙女木事件”. 相似文献
11.
V. V. Blinov N. G. Granin I. B. Mizandrontsev R. Yu. Gnatovskii A. A. Zhdanov 《Water Resources》2017,44(3):417-427
For the first time, T,S-analysis was used to determine the specifics of seasonal variations in the vertical structure of Lake Baikal active layer. In the under-ice period, the active layer includes the under-ice, top winter, and upper intermediate water masses. The under-ice water mass, unlike other masses, shows an increase in mineralization to 100.74 mg/kg, which corresponds to a release of 71.1 g salt under 1 m2 of water surface in a layer 0–40 m in the process of salt freezing out during ice cover formation and accretion. In the phases of mixing (homothermy), the water masses of the active layer transform into a surface homogeneous mass. In summer and autumn, surface and upper intermediate water masses, separated by a water mass of summer thermocline can be identified. A specific feature of the summer thermocline water mass is the increased sum of ions because of an increase in HCO 3 - concentration at the decay of organic matter accumulating in the bottom part of the thermocline. The existence of the under-ice water mass and the water mass of summer thermocline was established in Lake Baikal for the first time. In the deep-water zone (>250 m), except for the bottom parts, the lower water masses (the lower intermediate and the deep) are permanent, their characteristics remaining stable during the year. The changes in the bottom water mass are due to the character of the processes of bottom water renewal. 相似文献
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Hiroshi Kuroda Yuichi Hirota Takashi Setou Kazuhiro Aoki Daisuke Takahashi Tomowo Watanabe 《Ocean Dynamics》2014,64(1):47-60
To examine the properties of winter mixed layer (ML) variability in the shelf-slope waters facing the Kuroshio, we analyzed historical temperature records and the simulated results of a triply nested high-resolution numerical model. As a candidate of the shelf-slope waters, we focused on Tosa Bay, off the southern Japan. A time series of observed monthly mean ML temperatures and depths in the bay exhibits a remarkable seasonal variation. The period when the ML develops can be divided into two regimes: from September to November, when the sea surface cooling is gradually enhanced, the ML temperature and depth decreases and increases, respectively; from January to March, the ML temperature and depth are kept nearly constant, while the sea surface cooling in January reaches its annual maximum. In the latter regime, variance for the monthly mean ML depth is the largest of the year. To further study the ML properties in the latter regime corresponding to winter, we examined simulated results. It was found that the largest variance for ML depth is attributed to a dominant intramonthly variation. This is related to a submesoscale variation with typical spatial scales of 10–20 km, induced by the Kuroshio and its frontal disturbances. Simulated monthly mean heat balance within the ML showed that heat advection balances with heat flux at the sea surface and entrainment through the ML bottom. Moreover, the monthly mean heat advection is determined mainly by the intramonthly eddy heat advection, suggesting that the high-frequency intramonthly variation related to submesoscale variations contributes significantly to the low-frequency monthly variations of the ML in winter. 相似文献
13.
A. Alvera-Azcárate A. Barth R.H. WeisbergJ.J. Castañeda L. VandenbulckeJ.-M. Beckers 《Continental Shelf Research》2011,31(1):73-84
The spatial and temporal evolution of the thermocline depth and width of the Cariaco basin (Venezuela) is analysed by means of a three-dimensional hydrodynamic model. The thermocline depth and width are determined through the fitting of model temperature profiles to a sigmoid function. The use of whole profiles for the fitting allows for a robust estimation of the thermocline characteristics, mainly width and depth. The fitting method is compared to the maximum gradient approach, and it is shown that, under some circumstances, the method presented in this work leads to a better characterisation of the thermocline. After assessing, through comparison with independent in situ data, the model capabilities to reproduce the Cariaco basin thermocline, the seasonal variability of this variable is analysed, and the relationship between the annual cycle of the thermocline depth, the wind field and the distribution of chlorophyll-a concentration in the basin is studied. The interior of the basin reacts to easterly winds intensification with a rising of the thermocline, resulting in a coastal upwelling response, with the consequent increase in chlorophyll-a concentration. Outside the Cariaco basin, where an open ocean, oligothrophic regime predominates, wind intensification increases mixing of the surface layers and induces therefore a deepening of the thermocline. The seasonal cycle of the thermocline variability in the Cariaco basin is therefore related to changes in the wind field. At shorter time scales (i.e. days), it is shown that other processes, such as the influence of the meandering Caribbean current, can also influence the thermocline variability. The model thermocline depth is shown to be in good agreement with the two main ventilation events that took place in the basin during the period of the simulation. 相似文献
14.
新安江水库(千岛湖)水质时空变化特征及保护策略 总被引：14，自引：5，他引：9
为探索新安江水库(千岛湖)水质的变化规律及其影响因素,利用2009-2010年的逐月水质监测数据,结合文献资料,对新安江水库水质时空变化进行了综合分析.结果表明:在时间分布上,透明度、总氮、总磷及叶绿素受水文季节变化过程、浮游生物生长及人类活动等的综合影响,具有明显的季节变化特征,特别是上游街口断面各指标季节差异显著.空间分布上,上游水质明显劣于下游水质,上游水域透明度低,氮、磷及叶绿素含量高,反映出外源供给和人类活动对新安江水库水质的决定性贡献,控制外源污染是新安江水库水质提升的关键.统计分析表明,新安江水库主要感官指标透明度主要受控于藻类生物量,而藻类生物量变化与氮、磷营养盐的含量关系密切.严格控制入库营养盐通量,控制浮游植物生物量的季节性异常增殖已成为解决新安江水库水环境问题的核心.另外,新安江水库经济鱼类赋存量与捕捞量对水质有一定影响,年度捕捞量与水体透明度具有反相关关系,不能排除鱼类密度过高导致的生态系统失调的可能.因此,要进一步开展渔业养殖的水质效应研究,加强渔业管理,确定科学合理养殖模式,保证新安江水库水质的改善. 相似文献
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湖泊热力结构不仅影响湖泊内部生态环境,而且与区域气象和气候系统相互影响,但目前对湖泊垂直温度的观测研究仍非常匮乏.本研究基于青藏高原拉昂错连续的湖温和气象观测,分析了小时尺度和日尺度热力分层规律和混合层深度的变化特征.结果表明:拉昂错为冷多次完全混合型湖泊;湖表温度8月达到最大值,湖面敞水区和沿岸的湖表温度季节震荡相同,但存在一定的空间差异;与空气温度相比,湖表温度变幅小,降温更慢,峰值滞后约1个月.同时发现,拉昂错混合层深度变化较为规律,辐射和风速是影响湖泊混合层深度的主要外界因子.探明真实的高原湖泊分层规律,有利于提高湖泊模拟能力,为优化湖泊参数化方案提供参考. 相似文献
16.
Seasonal formation and movement of the thermocline in lakes 总被引：1，自引：0，他引：1
Summary The work described deals with the formation and movement of the thermocline on a lake during the summer season. The formation requires an input of mechanical energy from the wind stress as well as an input of heat from solar radiation or from the air. The depth of the thermocline is shown to be nearly proportional to the ratio of the energy input to the heat input and the thermocline sinks or ascends as one input is greater or less than the other. Formulae are found for the variation of the energyE with the cumulative effect of the wind speed, the temperature difference between the water and air if positive, and the depth of the thermocline. A similar formula is obtained forQ the heat input against the total number of hours of sunshine and the positive water-air temperature difference. From these two formulae it is possible to derive a formula for the thermocline depth entirely in terms of meteorological data and surface temperatures of the water for the season. 相似文献
17.
Remote sensing and ground‐based measurements of evapotranspiration in an extreme cold Patagonian desert 
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下载免费PDF全文 P. M. Cristiano D. A. Pereyra S. J. Bucci N. Madanes F. G. Scholz G. Goldstein 《水文研究》2016,30(24):4449-4461
Accurate estimates of seasonal evapotranspiration (ET) at different temporal and spatial scales are essential for understanding the biological and environmental determinants of ecosystem water balance in arid regions and the patterns of water utilization by the vegetation. For this purpose, remote sensing ET estimates of a Patagonian desert in Southern Argentina were verified with field measurements of soil evaporation and plant transpiration using an open top chamber. Root distribution and seasonal variation in soil volumetric water content were also analysed. There was a high correlation between remote sensing and field measurements of ecosystem water fluxes. A substantial amount of the annual ET occurred in spring and early summer (73.4 mm) using winter rain stored in the soil profile and resulting in water content depletion of the upper soil layers. A smaller amount of annual ET was derived from few rainfall events occurring during the mid or late summer (41.4 mm). According to remote sensing, the 92.9% of the mean annual precipitation returns to the atmosphere by transpiration or evaporation from the bare soil and by canopy interception. Only 7.1% infiltrates to soil layers deeper than 200 cm contributing to the water table recharge. Fourier time series analysis, cross‐correlation methods and multiple linear regression models were used to analyse 11 years of remote sensing data to assess determinants of water fluxes. A linear model predicts well the variables that drive complex ecosystem processes such as ET. Leaf area index and air temperature were not linearly correlated to ET because of the multiple interaction among variables resulting in time lags with ET variations and thus these two variables were not included in the linear model. Soil water content, the fraction of photosynthetic active radiation and precipitation explained 86% of the ET monthly variations. The high volumetric water content and the small seasonal variations at 200‐cm depth were probably the result of little water uptake from deeper soil horizons by roots with low hydraulic conductivity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
18.
浙江千岛湖深水区大型底栖动物时空变化格局 总被引：12，自引：4，他引：8
2007-2008年对浙江千岛湖深水区底栖动物群落进行了研究.共调查到8种底栖动物,其中寡毛类7种,线形动物门1种.群落类型不存在季节差异,优势种为霍甫水丝蚓和正颤蚓.群落年均密度和生物量分别为594.6ind./m~2和0.54g/m~2.双因素方差分析表明,密度和生物量无季节变化,但存在显著的空间差异,两者均是上游中游下游.密度和生物量与水深、透明度显著负相关,前者与水柱混合水样的TN和TP、与底部局部水样的TP显著正相关,后者与水柱混合水样的TP显著正相关.逐步回归分析表明,水深是密度和生物量的唯一最优解释因子,随水深增加密度和生物量均呈指数式下降. 相似文献
19.
《中国科学:地球科学(英文版)》2017,(12)
Lake Zigetang is located on the central Tibetan Plateau(TP) and represents a rare but typical meromictic lake in China.The lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria(APB) was demonstrated by the discovery of bacteriopheophytin-a(Bph-a) in the sediments.This bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer,which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes. 相似文献