Strengths and weaknesses of multi-year Envisat ASAR backscatter measurements to map permanent open water bodies at global scale

Permanent water bodies not only store dissolved CO2 but are essential for the maintenance of wetlands in their proximity. From the viewpoint of greenhouse gas (GHG) accounting wetland functions comprise sequestration of carbon under anaerobic conditions and methane release. The investigated area in central Siberia covers boreal and sub-arctic environments. Small inundated basins are abundant on the sub-arctic Taymir lowlands but also in parts of severe boreal climate where permafrost ice content is high and feature important freshwater ecosystems. Satellite radar imagery (ENVISAT ScanSAR), acquired in summer 2003 and 2004, has been used to derive open water surfaces with 150 m resolution, covering an area of approximately 3 Mkm2. The open water surface maps were derived using a simple threshold-based classification method. The results were assessed with Russian forest inventory data, which includes detailed information about water bodies. The resulting classification has been further used to estimate the extent of tundra wetlands and to determine their importance for methane emissions. Tundra wetlands cover 7% (400 000 km2) of the study region and methane emissions from hydromorphic soils are estimated to be 45 000 t d−1 for the Taymir peninsula.

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Assessing Envisat ASAR and Sentinel-1 multi-temporal observations to map open water bodies

2015 IEEE 5th Asia-Pacific Conference on Synthetic Aperture Radar (APSAR) ◽

10.1109/apsar.2015.7306283 ◽

2015 ◽

Author(s):

Maurizio Santoro ◽

Urs Wegmuller ◽

Andreas Wiesmann ◽

Celine Lamarche ◽

Sophie Bontemps ◽

...

Keyword(s):

Open Water ◽

Water Bodies ◽

Envisat Asar ◽

Multi Temporal

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Parametrization of lakes water dynamics in the ISBA-CTRIP land surface system (SURFEX v8.1)

10.5194/gmd-2020-296 ◽

2020 ◽

Author(s):

Thibault Guinaldo ◽

Simon Munier ◽

Patrick Le Moigne ◽

Aaron Boone ◽

Bertrand Decharme ◽

...

Keyword(s):

Lake Level ◽

Hydrological Modeling ◽

Lake Victoria ◽

Open Water ◽

Global Scale ◽

Water Bodies ◽

Water Dynamics ◽

Lake Levels ◽

The Impact ◽

River Routing

Abstract. Lakes are of fundamental importance in the Earth system as they support essential environmental and economic services such as freshwater supply. They also modify the local hydro-meteorological continuum as a lower boundary of the atmosphere. Sentinels of climate change and anthropization, these open water bodies are facing disruptions of their equilibrium generally leading to a notable reduction of their levels worldwide. Stream-flow variability and temporal evolution are impacted by the presence of lakes in the river network, therefore any change in the lake state can induce a modification of the regional hydrological regime. Despite the importance of the impact of lakes on hydrological fluxes and the water balance, a representation of the mass budget is generally not included in climate models and global scale hydrological modeling platforms. The goal of this study is to introduce a new lake mass module, MLake (Mass-Lake model), into the river routing model CTRIP to resolve the specific mass-balance of open water bodies. Based on the inherent CTRIP parameters, the development of the non-calibrated MLake model was introduced to examine the influence of such hydrological buffer areas on the global scale river routing performances. In the current study, an off-line evaluation was performed for four river networks using a set of state-of-the-art quality atmospheric forcings and a combination of in situ and satellite measurements for river discharge and lake level observations. The results reveal a general improvement in CTRIP simulated discharge and its variability, while also generating realistic lake level variations. MLake produces more realistic streamflows both in terms of daily and seasonal correlation. Excluding the specific case of Lake Victoria having low performances, the mean skill score of Kling-Gupta Efficiency (KGE) is 0.41 while the Normalized Information Contribution (NIC) shows a mean improvement of 0.56 (ranging from 0.15 to 0.94). Streamflow results are spatially scale-dependent, with better scores associated with larger lakes, and increased sensitivity to the width of the lake outlet. Regarding lake levels variations, results indicate a good agreement between observations and simulations with a mean correlation of 0.56 (ranging from 0.07 to 0.92) which is linked to the capability of the model to retrieve seasonal variations. Discrepancies in the results are mainly explained by the anthropization of the selected lakes which introduces high-frequency variations in both streamflows and lake levels that degraded the scores. Anthropization effects are prevalent in most of the lakes studied, but they are predominant for Lake Victoria and are the main cause for relatively low statistical scores for this river. However, results on the Angara and the Neva rivers also depend on the inherent gap of ISBA-CTRIP processes representation which relies on further development such as the partitioned energy budget between the snow and the canopy over a Boreal zone. The study is a first step towards a global coupled land system that will help to qualitatively assess the evolution of future global water resources leading to improvements in flood risk and drought forecasting.

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Influence of Open Water Bodies on the Modeling of Summertime Convection over the Canadian Prairies

Journal of Hydrometeorology ◽

10.1175/jhm-d-15-0225.1 ◽

2017 ◽

Vol 18 (6) ◽

pp. 1583-1594

Author(s):

Deepti Joshi ◽

Marco Carrera ◽

Stephane Bélair ◽

Sylvie Leroyer

Keyword(s):

Convective Available Potential Energy ◽

Open Water ◽

Water Bodies ◽

Convective Precipitation ◽

Precipitation Event ◽

Canadian Prairies ◽

Water Fraction ◽

Weather Patterns ◽

Global Environmental ◽

Land Water

Abstract There are numerous water features on the Canadian landscapes that are not monitored. Specifically, there are water bodies over the prairies and Canadian shield regions of North America that are ephemeral in nature and could have a significant influence on convective storm generation and local weather patterns through turbulent exchanges of sensible and latent heat between the land and the atmosphere. In this study a series of numerical experiments is performed with Environment and Climate Change Canada’s Global Environmental Multiscale (GEM) model at 2.5-km grid spacing to examine the sensitivity of the atmospheric boundary layer and the resulting precipitation to the presence of open water bodies. Operationally, the land–water fraction in GEM is specified by means of static geophysical databases that do not change with time. Uncertainty is introduced in this study into this land–water fraction and the sensitivity of the resulting precipitation is quantified for a convective precipitation event occurring over the Canadian Prairies in the summer of 2014. The results indicate that with an increase in open water bodies, accumulated precipitation, peak precipitation amounts, and intensities decrease. Moreover, shifts are seen in times of peak for both precipitation amounts and intensities, in the order of increasing wetness. Additionally, with an increase in open water bodies, convective available potential energy decreases and convective inhibition increases, indicating suppression of forcing for convective precipitation.

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Methodical approaches to the evaluation of surface pollution of water objects in the area of mining enterprises (on the example of Donetsk-Pridniprovsk region)

Institute of Telecommunications and Global Information Space of the National Academy of Sciences of Ukraine ◽

10.32347/2411-4049.2021.3.69-75 ◽

2021 ◽

Vol 39 (3) ◽

pp. 69-75

Author(s):

Olena Voloshkina ◽

Olena Zhukova ◽

Irina Korduba ◽

Daniil Marshall

Keyword(s):

Water Quality ◽

Water Cycle ◽

Surface Water Quality ◽

Global Scale ◽

Ecological Condition ◽

Water Bodies ◽

Anthropogenic Factors ◽

Chemical Indicators ◽

Quality Of Water ◽

Long Time

The most important component of ecologically safe development of natural and socio-economic systems is the use of nature, which involves the organization of water resources, which ensures sustainable development and for a long time retains sufficient water potential. The ХХІ century is characterized by significant negative changes in the natural environment caused by the uncontrolled use of natural resources, the development of industry and transport, which leads to increased water consumption and at the same time increase its pollution. This has been particularly noticeable over the last 50 years, when human impact on the planet's water cycle has reached a global scale. Deterioration of the ecological condition of surface waters is due to qualitative and quantitative depletion of factors of their formation, which in some cases makes it impossible to use them for economic purposes. Water quality of water bodies is formed under the influence of both natural and anthropogenic factors. As a result of human activity in reservoirs many anthropogenic substances of various degree of toxicity can arrive. The article attempts to assess changes in surface water quality over the past decade and to determine the degree of natural and man-made transformation of rivers in the region and the possibility of their self-restoration and stabilization of the ecological danger of the region. The existing methods of assessment of water bodies by chemical indicators used in the area of operation of mining enterprises are considered. In some methods, the assessment of water bodies usually reflects regional features rather than their own pollution. Calculations for the water basin river Siverskyi Donets are made and relevant patterns are established.

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Ist Wasserbau auch eine Frage der Ästhetik? | Is hydraulic engineering a question of aesthetics?

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2008.0205 ◽

2008 ◽

Vol 159 (7) ◽

pp. 205-208

Author(s):

Gianni Paravicini

Keyword(s):

Open Water ◽

Hydraulic Engineering ◽

Water Bodies ◽

Ecological Value ◽

The Aesthetic ◽

Bodies Of Water

There is much extended literature about classic technical hydraulic engineering and about the revitalization of bodies of water. This article deals with a third component, which has received little attention by the engineers. The author pleads for more aesthetic in hydraulic engineering, in particular in populated areas where many people use the open water bodies for recreation. It is shown that more aesthetic in hydrologic engineering often also leads to an increased ecological value. With hydraulic constructions in the canton of Lueerne, possible creative elements for the aesthetic and ecological revaluation of the course of creeks are discussed.

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A multi-temporal remote sensing approach for monitoring changes in spatial extent of freshwater lake of Deepor Beel Ramsar Site, a major wetland of Assam

Journal of Wetlands Ecology ◽

10.3126/jowe.v5i0.4696 ◽

2011 ◽

Vol 5 ◽

pp. 40-47 ◽

Cited By ~ 10

Author(s):

Jyotishman Deka ◽

Om Prakash Tripathi ◽

Mohammad Latif Khan

Keyword(s):

Open Water ◽

Management Plan ◽

Rate Of Change ◽

Freshwater Lake ◽

Landsat Tm ◽

Water Bodies ◽

Food Storage ◽

Data Mapping ◽

Wetland Ecosystem ◽

Rapid Urbanization

Sustainability of wetland ecosystem is necessary for various important functions such as food storage, water quality continuation and providing habitat for different species of flora and fauna. Hence, an inventory of wetlands of any region is a pre-requisite for their conservation and management. This study has been carried out to delineate the change in freshwater lake of ‘Deepor Beel’ wetland of Assam, India, using LANDSAT TM data. Field observation shows that the ecosystem is facing both natural as well as anthropogenic threats. Rapid urbanization, Illegal settlements, industries, invasive species (Eichhornia crassipes) are the major cause of this wetland decline. It has been found that massive decline occurred between the period 1991 to 2001 i.e., 1.891 sq.km which was at the rate of -0.171 per year where as the decline between the period 2001 to 2010 was found to be 1.013 sq. km which was at a rate of -0.101. The total area of open water bodies has decreased by 2.904 sq. km from 1991 to 2010 i.e. 59.19%. Thus the overall rate of change in the water bodies from 1991 to 2010 to other land use categories was found to be -0.145. Hence the study reveals the potentiality of Landsat TM data mapping the change in the wetland ecosystem. It is further hoped that the study will have high utility in preparing management plan for conservation of this ecosystem. Keywords: Wetland; Landsat TM; Thresholding; density sliceDOI: http://dx.doi.org/10.3126/jowe.v5i0.4696 J Wet Eco 2011 (5): 40-47

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Spatial and Temporal Dynamics of Urban Wetlands in an Indian Megacity over the Past 50 Years

Remote Sensing ◽

10.3390/rs12040662 ◽

2020 ◽

Vol 12 (4) ◽

pp. 662 ◽

Cited By ~ 2

Author(s):

Katja Brinkmann ◽

Ellen Hoffmann ◽

Andreas Buerkert

Keyword(s):

Land Cover ◽

Urban Areas ◽

Temporal Dynamics ◽

Open Water ◽

Water Bodies ◽

Annual Rainfall ◽

Urban Wetlands ◽

Landsat Images ◽

Urban District ◽

Wetland Area

Asian megacities have attracted much scientific attention in the context of global urbanization, but few quantitative studies analyze wetland transformation in the rural–urban interface. With its rampant growth and transformation from a tree-lined “Garden City” to a busy megalopolis with often-blocked highways and large built-up areas, Bengaluru (Karnataka, S-India) is a good example for assessing how urbanization has led to the acute degradation of wetlands. We therefore investigated long-term land cover and wetland changes from 1965 to 2018 based on an object-based classification of multi-temporal Corona and Landsat images. To quantify and compare the dynamics of open water surfaces and vegetation, we defined the potential wetland areas (PWA) along the rural–urban gradient and linked our analyses to an index describing the degree of urbanization (survey stratification index (SSI)). During the five decades studied, built-up areas in the Bengaluru Urban district increased ten-fold, with the highest growth rate from 2014 to 2018 (+ 8% annual change). Patches of lake wetlands were highly dynamic in space and time, partly reflecting highly variable annual rainfall patterns ranging from 501 mm in 1965 to 1374 mm in 2005 and monsoon-driven alterations in the hydrologic regime. While water bodies and flooded areas shrunk from 64 km2 in 1965 to 55 km2 in 2018, in 1965, the total rural wetland area with an SSI > 0.5 was twice as high as in 2018. The rural–urban land cover pattern within potential wetland areas changed drastically during this period. This is reflected, for example, by a four-fold increase in the wetland area with an SSI of 0.3, as compared to a decline by 43% in wetland area with an SSI of 0.8. While, in urban areas, wetlands were mostly lost to construction, in areas with a rural character, open water bodies were mainly transformed into green space. The detected changes in urban wetlands were likely accompanied by ecological regime changes, triggering deteriorations in ecosystem services (ESS) which merit further research.

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