Monitoring of water surface temperature of Eurasian large lakes using MODIS land surface temperature product     

Jia Du  Pierre-Andre Jacinthe  Haohao Zhou  Xiaoyun Xiang  Boyu Zhao  Min Wang  Kaishan Song 《水文研究》2020,34(16):3582-3595

In this study, data from MODIS land surface temperature product level 3 (MOD11A2) were used to investigate the spatiotemporal variation of Eurasian lakes water surface temperature (LSWT) from 2001 to 2015, and to examine the most influencing factors of that variation. The temperature of most lakes in the dry climate zone and in the equatorial climatic zone varied from 17 to 31°C and from 23 to 27°C, respectively. LSWTs in the warm temperate and cold climatic zones were in the range of 20 to 27°C and −0.6 and 17°C, respectively. The average day time LSWT in the polar climate zone was −0.71°C in the summer. Lakes in high latitude and in the Tibetan Plateau displayed low LSWT, ranging from −11 to 26°C during the night time. Large spatial variations of diurnal temperature difference (DTD) were observed in lakes across Eurasia. However, variations in DTDs were small in lakes located in high latitude and in tropical rainforest regions. The shallow lakes showed a rapid response of LSWT to solar and atmospheric forcing, while in the large and deep lakes, that response was sluggish. Results of this study demonstrated the applicability of remote sensing and MODIS LST products to capture the spatial–temporal variability of LSWT across continental scales, in particular for the vast wilderness areas and protected environment in high latitude regions of the world. The approach can be used in future studies examining processes and factors controlling large scale variability of LSWT.  相似文献   

Hydrogeomorphic processes of thermokarst lakes with grounded‐ice and floating‐ice regimes on the Arctic coastal plain,Alaska     

Christopher D. Arp  Benjamin M. Jones  Frank E. Urban  Guido Grosse 《水文研究》2011,25(15):2422-2438

Thermokarst lakes cover > 20% of the landscape throughout much of the Alaskan Arctic Coastal Plain (ACP) with shallow lakes freezing solid (grounded ice) and deeper lakes maintaining perennial liquid water (floating ice). Thus, lake depth relative to maximum ice thickness (1·5–2·0 m) represents an important threshold that impacts permafrost, aquatic habitat, and potentially geomorphic and hydrologic behaviour. We studied coupled hydrogeomorphic processes of 13 lakes representing a depth gradient across this threshold of maximum ice thickness by analysing remotely sensed, water quality, and climatic data over a 35‐year period. Shoreline erosion rates due to permafrost degradation ranged from < 0·2 m/year in very shallow lakes (0·4 m) up to 1·8 m/year in the deepest lakes (2·6 m). This pattern of thermokarst expansion masked detection of lake hydrologic change using remotely sensed imagery except for the shallowest lakes with stable shorelines. Changes in the surface area of these shallow lakes tracked interannual variation in precipitation minus evaporation (P ? E_L) with periods of full and nearly dry basins. Shorter‐term (2004–2008) specific conductance data indicated a drying pattern across lakes of all depths consistent with the long‐term record for only shallow lakes. Our analysis suggests that grounded‐ice lakes are ice‐free on average 37 days longer than floating‐ice lakes resulting in a longer period of evaporative loss and more frequent negative P ? E_L. These results suggest divergent hydrogeomorphic responses to a changing Arctic climate depending on the threshold created by water depth relative to maximum ice thickness in ACP lakes. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Latest Pleistocene and Holocene glacial events in the Colonia valley,Northern Patagonia Icefield,southern Chile          下载免费PDF全文

David A. Nimick  Daniel McGrath  Shannon A. Mahan  Beverly A. Friesen  Jonathan Leidich 《第四纪科学杂志》2016,31(6):551-564

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Sedimentary response of lake El Tobar,Spain, to climate: lake level changes after the Maunder Minimum          下载免费PDF全文

Charo López‐Blanco  Julian Andrews  Paul Dennis  María Rosa Miracle  Eduardo Vicente 《第四纪科学杂志》2016,31(8):905-918

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Late Holocene fluctuations of Quelccaya Ice Cap,Peru, registered by nearby lake sediments          下载免费PDF全文

Justin S. Stroup  Meredith A. Kelly  Thomas V. Lowell  Colby A. Smith  Samuel A. Beal  Joshua D. Landis  Pedro M. Tapia 《第四纪科学杂志》2015,30(8):830-840

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Modelling the effects of soil type and root distribution on shallow groundwater resources          下载免费PDF全文

Stefania Grimaldi  Felipe Orellana  Edoardo Daly 《水文研究》2015,29(20):4457-4469

Vegetated, shallow groundwater environments typically have high environmental and economic value. A sound understanding of the complex interactions and feedbacks between surface vegetation and groundwater resources is crucial to managing and maintaining healthy ecosystems while responding to human needs. A vegetated shallow groundwater environment was modelled using the software HYDRUS 2D to investigate the effects of several combinations of soil type and root distributions on shallow groundwater resources. Three rainfall regimes coupled to both natural and anthropogenically affected groundwater conditions were used to investigate the effect that combinations of four soil types and five root distributions can have on (a) groundwater level drops, (b) groundwater depletion, (c) groundwater recharge and (d) water stress conditions. Vegetation with roots distributed across the whole unsaturated zone and vegetation with dimorphic root systems (i.e. roots having larger concentrations both near the surface and the capillary fringe) behaved differently from vegetation growing roots mainly near the saturated zone. Specifically, vegetation with roots in the unsaturated zone caused water‐table drops and groundwater depletions that were half the amount due to deep‐rooted vegetation. Vegetation with a large portion of roots near the soil surface benefited from rainfall and was less vulnerable to water‐table lowering; as such, the fraction of the total area of roots affected by water stress conditions could be 40% smaller than in the case with deep‐rooted vegetation. However, roots uniformly distributed in the unsaturated zone could halve groundwater recharge rates observed in bare soils. Our analysis provided insights that can enable the formulation of site‐ and purpose‐specific management plans to respond to both human and ecosystem water requirements. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Heterogeneous change patterns of water level for inland lakes in High Mountain Asia derived from multi‐mission satellite altimetry          下载免费PDF全文

Chunqiao Song  Bo Huang  Linghong Ke 《水文研究》2015,29(12):2769-2781

High‐altitude inland lakes in High Mountain Asia (HMA) are key indicators to climate change and variability as a result of mostly closed watersheds and minimal disturbance by human activities. However, examination of the spatial and temporal pattern of lake changes, especially for water‐level variations, is usually limited by poor accessibility of most lakes. Recently, satellite altimeters have demonstrated their potential to monitor water level changes of terrestrial water bodies including lakes and rivers. By combining multiple satellite altimetry data provided by the Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS) and Geoscience Laser Altimeter System (GLAS) instrument on the NASA Ice, Cloud and land Elevation satellite (ICESat), this study examined water level changes of typical lakes in HMA at a longer timescale (in the 1990s and 2000s) compared with earlier studies on Tibetan lakes. Cross‐evaluation of the radar altimetry data from LEGOS and laser altimetry data from ICESat/GLAS shows that they were in good agreement in depicting inter‐annual, seasonal and abrupt changes of lake level. The long‐term altimetry measurements reveal that water‐level changes of the 18 lakes showed remarkable spatial and temporal patterns that were characterized by different trends, onsets of rapid rises and magnitudes of inter‐annual variations for different lakes. During the study period, lakes in the central and northern HMA (15 lakes) showed a general growth tendency, while lakes in South Tibet (three lakes) showed significant shrinking tendency. Lakes in Central Tibet experienced rapid and stable water‐level rises around mid‐1990s followed by slowing growth rates after 2006. In contrast, the water‐level rises of lakes in the northern and north‐eastern Tibetan Plateau were characterized by abrupt increases in specific years rather than gradual growth. Meteorological data based on station observations indicate that the annual changes of water level showed strongly correlated with precipitation and evaporation but may not evidently related to the glacier melting induced by global warming. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Impacts of regional warming on long‐term hypolimnetic anoxia and dissolved oxygen concentration in a deep lake          下载免费PDF全文

Yuji Ito  Kazuro Momii 《水文研究》2015,29(9):2232-2242

Although few reports have described long‐term continuous anoxia in aquatic systems, Lake Ikeda in Japan experienced such conditions in the hypolimnion from 1990 to 2010. The present study aimed to assess temporal fluctuations in the lake's thermal stability from 1978 to 2011 to understand the influence of regional climate change on hypolimnetic anoxia in this lake. Because complete vertical mixing, which supplies dissolved oxygen (DO) to the hypolimnion, potentially occurs on February, we calculated the Schmidt stability index (S) in February and compared it with hypolimnetic DO dynamics. Vertical water temperature profiles were calculated using a one‐dimensional model, and calculated temperatures and meteorological data were used to analyse annual fluctuations in water temperatures, thermocline depth, meteorological variables and S. We estimated that mean annual air and volume‐weighted water temperatures increased by 0.028 and 0.033 °C year^?1, respectively, from 1978 to 2011. Between 1986 and 1990, S and water temperature increased abruptly, probably due to a large upwards trend in air temperature (+0.239 °C year^?1). We hypothesize that a mixing regime that lacked overturn took effect at this time and that this regime lasted until 2011, when S was particularly small. These results demonstrate that abrupt climate warming in the late 1980s likely triggered the termination of complete mixing and caused the 21‐year period of successive anoxia in Lake Ikeda. We conclude that the lake response to a rapid shift in regional climate conditions was a key factor in changing the hypolimnetic water environment and that thermal stability in winter is a critical environmental factor controlling the mixing regime and anoxic conditions in deep lakes. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

基于MNDWI特征空间的水体追踪识别方法研究     

屈慧慧  裴亮  桑学锋  王金鑫 《测绘工程》2021,30(2):32-35,44

水体作为国土资源的关键要素,其水体面积变化在水资源调查、变化检测及大型水利设施建设评估等方面具有非常重要的意义。由于区域山体阴影、建筑等因素的干扰影响,带来域内所有湖库水体进行一次性提取的难点,文中以landsat8为数据源,研究提出一种MNDWI+水体追踪识别的方法;并以京津冀区域为例,应用本方法在该区域湖库水体的提取精度达到97.5%以内,与常规方法相比,实现了大区域湖库水体的一次性快速精确提取。  相似文献   

Ecosystem services or services to ecosystems? Valuing cultivation and reciprocal relationships between humans and ecosystems     

《Global Environmental Change》2015

The concept of Ecosystem Services (ES), widely understood as the “benefits that humans receive from the natural functioning of healthy ecosystems” (Jeffers et al., 2015), depicts a one-way flow of services from ecosystems to people. We argue that this conceptualisation is overly simplistic and largely inaccurate, neglecting the reality that humans often contribute to the maintenance and enhancement of ecosystems, as often evidenced (but not exclusively) in many traditional and Indigenous societies. Management interventions arising from Ecosystem Services research are thus potentially damaging to both ecosystems and indigenous rights. We present the concept of ‘Services to Ecosystems’ (S2E) to address this, closing the loop of the reciprocal relationship between humans and ecosystems. Case studies from the biocultural ecosystems of Amazonia and the Pacific Northwest of North America (Cascadia) are used to illustrate the concept and provide examples of Services to Ecosystems in past and current societies. Finally, an alternative framework is presented, advancing the existing framework for Ecosystem Services by incorporating this reconceptualization and the loop of reciprocity. The framework aims to facilitate the inclusion of Services to Ecosystems in management strategies based upon Ecosystem Services, and highlights the need for ethnographic research in Ecosystem Service-based interventions.  相似文献