scholarly journals The 2019–2020 Rise in Lake Victoria Monitored from Space: Exploiting the State-of-the-Art GRACE-FO and the Newly Released ERA-5 Reanalysis Products

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4304
Author(s):  
Mehdi Khaki ◽  
Joseph Awange
Keyword(s):  
Lake Victoria ◽  
Water Discharge ◽  
Water Storage ◽  
The State ◽  
Water Levels ◽  
Subsurface Water ◽  
Surface Model ◽  
The Past ◽  
Short Rainy Season ◽  
Spatial Coverage

During the period 2019–2020, Lake Victoria water levels rose at an alarming rate that has caused various problems in the region. The influence of this phenomena on surface and subsurface water resources has not yet been investigated, largely due to lack of enough in situ measurements compounded by the spatial coverage of the lake’s basin, incomplete/inconsistent hydrometeorological data, and unavailable governmental data. Within the framework of joint data assimilation into a land surface model from multi-mission satellite remote sensing, this study employs the state-of-art Gravity Recovery and Climate Experiment follow-on (GRACE-FO) time-variable terrestrial water storage (TWS), newly released ERA-5 reanalysis, and satellite radar altimetry products to understand the cause of the rise of Lake Victoria on the one hand, and the associated impacts of the rise on the total water storage compartments (surface and groundwater) triggered by the extreme climatic event on the other hand. In addition, the study investigates the impacts of large-scale ocean–atmosphere indices on the water storage changes. The results indicate a considerable increase in water storage over the past two years, with multiple subsequent positive trends mainly induced by the Indian Ocean Dipole (IOD). Significant storage increase is also quantified in various water components such as surface water and water discharge, where the results show the lake’s water level rose by ∼1.4 m, leading to approximately 1750 gigatonne volume increase. Multiple positive trends are observed in the past two years in the lake’s water storage increase with two major events in April–May 2019 and December 2019–January 2020, with the rainfall occurring during the short rainy season of September to November (SON) having had a dominant effect on the lake’s rise.

Integrated Spatial and Economic Analysis on Water Infrastructure Expansion Profitability and Affecting Climatic Factors within the Central Valley of California

2021 ◽  
Author(s):  
Mahesh Lal Maskey ◽  
Liying Li ◽  
Angel S. Fernandez-Bou ◽  
Joshua H. Viers ◽  
Josue Medellin-Azuara
Keyword(s):  
Water Supply ◽  
Water Allocation ◽  
Climatic Factors ◽  
Water Storage ◽  
Subsurface Water ◽  
Past Century ◽  
Water Infrastructure ◽  
California Department ◽  
The Past ◽  
Optimal Water Allocation

<p>Climate signals have been consistently changing over the past century, together with increased population and human activities. Consequently, notable shifts in timing and magnitude of floods and drought and declining surface and subsurface water storage have been seriously posing effects on water supply and demand throughout the planet. Hence, it becomes relevant to understand the optimal water allocation to different water users such as agriculture, urban, environmental, and wildlife refuge and manage water infrastructure projects accordingly to support optimal water allocation. In the past, we have shown the successful application of the statewide hydro-economic model, also known as CALVIN (California Value Integrated Network)<sup>1,2</sup>, to minimize water allocation costs and optimize water utility under the policy, operational, and environmental constraints.</p><p>This study utilizes economic and water allocation output from the CALVIN model historical run (1921 to 2003; monthly scale), and it explores the opportunity cost of water storage and conveyance expansion in California (economic data based on 2050 projected water use<sup>3,4</sup>). This study performs a time series analysis on the marginal economic value of expansion to characterize the correlation between historical climatic factors with water allocation capacity extension to characterize how climate events such as droughts or floods can affect the profitability of water infrastructure expansion projects. The result provides useful information for statewide planners and decision-makers in setting coping strategies for the future under climate change conditions<sup>5,6</sup>. Additionally, this study uses the historical run expansion cost results to identify the most profitable water infrastructure expansion locations using spatial analysis. This study concentrates on agriculture and urban water demands from surface and groundwater sources and categorizes the water allocation over different water years dictated by the California Department of Water Resources (DWR). This study offers a holistic approach to elucidate responses of existing water supply-demand nexus, and the results will be useful for the Sustainable Groundwater Management Act (SGMA) of California.</p><p><strong>References:</strong></p><p> </p>

scholarly journals Water discharge and sediment flux changes over the past decades in the Lower Mekong River: possible impacts of the Chinese dams

2006 ◽  
Vol 10 (2) ◽  
pp. 181-195 ◽  
Author(s):  
X. X. Lu ◽  
R. Y. Siew
Keyword(s):  
Water Discharge ◽  
Sediment Concentration ◽  
Dry Season ◽  
Water Levels ◽  
Sediment Flux ◽  
Mekong River ◽  
Water Level Fluctuations ◽  
Main Stream ◽  
The Past ◽  
Ecological Changes

Abstract. The Lower Mekong River has witnessed extremely low water levels over the past few years. There is speculation that the changes are a consequence of the construction and operation of the Chinese cascade dams in the upper part of the Mekong main stream, the Lancang River. Dam construction on upper streams can produce a series of induced effects downstream, particularly in terms of water, sediment, channel and ecological changes. Analyses of discharge and sediment flux at various gauging stations on the Lower Mekong River have indicated a disruption in water discharge, water fluctuations and sediment transport downstream of the first Chinese dam among the 8 cascades (i.e. the Manwan Dam), after its reservoir was infilled in 1992. Dry season flows showed a declining trend, and water level fluctuations in the dry season increased considerably in the post-dam (1993–2000) period. Monthly suspended sediment concentration (SSC) has also decreased significantly in several gauging stations in the post-dam period. The estimation of sediment flux is challenging since the measurements of SSC were sporadic. Our estimation based on the available data indicated that the areas along the upper-middle and lowermost reaches of the Mekong River have experienced a decline in sediment flux, possibly due to sedimentation in the Manwan Dam. However, the decrease is only statistically significant at the nearest gauging station below the Dam (i.e. Chiang Saen). Areas located in the mid-length of the river show less sensitivity to the operation of the Manwan Dam, as sediment fluxes have remained stable or even increased in the post-dam period.

Cooling artificial turf through evaporation from a subsurface water storage unit

2021 ◽  
Author(s):  
Marjolein van Huijgevoort ◽  
Gijsbert Cirkel
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
High Surface ◽  
Water Storage ◽  
Water Levels ◽  
Subsurface Water ◽  
Heat Island ◽  
Artificial Turf ◽  
Natural Grass ◽  
Island Effect

<p>The increase in population in cities has led to increased pressure on available sport facilities. As a result, natural grass fields are converted to artificial turf, because fields with artificial turf can be used more frequently. Downsides of these artificial turf fields are the increase in surface temperature and the decrease in infiltration of precipitation resulting in faster discharge. Artificial turf can reach very high surface temperatures leading to unplayable fields and health risks, but also contributing to the urban heat island effect. To counteract these high temperatures, irrigation of the fields is needed, which leads to high water demands. In this study, a system to store precipitation below the fields and to enable evaporation to cool the artificial turf was tested. The system consists of water-storing units below the field, a capillary shockpad that enables water transport to the artificial turf and a natural infill from where water can evaporate. To quantify the effects on temperature and evaporation of the system, four test sites were created with natural grass, conventional artificial turf and two versions of the cooled artificial turf (non-infill and standard). All sites were equipped to measure evaporation, surface temperature, net radiation and water levels below the fields. A separate weather station was installed to measure other meteorological variables (e.g. precipitation, air temperature, wind). During the summer of 2020 on days with a maximum air temperature around 30°C, surface temperature reached 37°C at the cooled standard artificial grass, whereas it reached 62.5°C at the conventional artificial turf. The measured surface temperature for the cooled turf was less than 2°C warmer than the surface temperature at the natural grass site (35.3°C). Evaporation from the cooled artificial turf reached maximum values around 4 mm/d during the summer and was about half of the evaporation from natural grass, whereas evaporation from conventional artificial turf was close to zero. These results show that the system is successful in lowering the surface temperature by evaporation. This reduction in surface temperature is important to maintain playable conditions, but also helps to mitigate the heat island effect. In addition, the water storage below the fields reduces peak discharges during high-intensity precipitation. By combining these functions, the cooled artifical turf fields can help cities adapt to climate change.</p>

scholarly journals Monitoring Lake Levels From Space: Preliminary Analysis With SWOT

2021 ◽  
Vol 3 ◽  
Author(s):  
Akhilesh S. Nair ◽  
Nitish Kumar ◽  
J. Indu ◽  
B. Vivek
Keyword(s):  
Surface Water ◽  
Temporal Resolution ◽  
Anthropogenic Activities ◽  
Rapid Change ◽  
Water Storage ◽  
Water Levels ◽  
Study Region ◽  
Volume Calculation ◽  
Spatial Coverage

Lakes are an essential component of biogeochemical processes, and variations in lake level are regarded as indicators of climate change. For more than a decade, satellite altimetry has successfully monitored variation in water levels over inland seas, lakes, rivers, and wetlands. Through altimetry, the surface water levels are measured at varying temporal scales depending on the orbit cycle of the satellite. The futuristic mission of Surface Water and Ocean Topography (SWOT) scheduled to be launched in year 2022 shall offer the spatial coverage and resolution suitable for water level estimation and volume calculation in small water bodies like lakes worldwide. With a radar interferometer in Ka-band, SWOT proposes to provide two-dimensional maps of water heights 21 days repeat orbit configuration. Cycle average SWOT datasets for land will be developed with higher temporal resolution, with temporal resolution varying geographically. This work assesses the potential of SWOT for monitoring water volumes over a case study lake by analyzing SWOT like synthetic data produced using the SWOT simulator developed by the Centre National d'Etudes Spatiales (CNES). With SWOT relying on a novel technology, the initial 90 days of this mission after launch shall focus on an extensive calibration and validation. Firsthand results of SWOT-simulated water levels and volumes are presented over a case study region in the tropical band, namely, Pookode Lake, in the ecologically fragile district of Wayanad, Kerala, India. It is the second-largest freshwater lake in Kerala that is being affected by anthropogenic activities, causing huge depletion in lake water storage in the last four decades. Our analysis indicated that the lake region is subjected to a rise in temperature of 0.018°C per year. We further assess the potential of remote sensing and SWOT data to monitor water storage of Pookode Lake, which is undergoing a rapid change. Results show that the proxy water surface elevations have immense potential in scientific studies pertaining to lake monitoring across the world. Overall, the study shows the potential of SWOT for monitoring the variability of water levels and volumes in this region.

Collective Memory: Between Values and Historical Knowledge

2020 ◽  
pp. 124-142
Author(s):  
VICTOR BURLACHUK
Keyword(s):  
Twentieth Century ◽  
Soviet Union ◽  
Collective Memory ◽  
Rapid Change ◽  
Modern Society ◽  
The State ◽  
Main Element ◽  
Rapid Decline ◽  
The Past ◽  
The Future

At the end of the twentieth century, questions of a secondary nature suddenly became topical: what do we remember and who owns the memory? Memory as one of the mental characteristics of an individual’s activity is complemented by the concept of collective memory, which requires a different method of analysis than the activity of a separate individual. In the 1970s, a situation arose that gave rise to the so-called "historical politics" or "memory politics." If philosophical studies of memory problems of the 30’s and 40’s of the twentieth century were focused mainly on the peculiarities of perception of the past in the individual and collective consciousness and did not go beyond scientific discussions, then half a century later the situation has changed dramatically. The problem of memory has found its political sound: historians and sociologists, politicians and representatives of the media have entered the discourse on memory. Modern society, including all social, ethnic and family groups, has undergone a profound change in the traditional attitude towards the past, which has been associated with changes in the structure of government. In connection with the discrediting of the Soviet Union, the rapid decline of the Communist Party and its ideology, there was a collapse of Marxism, which provided for a certain model of time and history. The end of the revolutionary idea, a powerful vector that indicated the direction of historical time into the future, inevitably led to a rapid change in perception of the past. Three models of the future, which, according to Pierre Nora, defined the face of the past (the future as a restoration of the past, the future as progress and the future as a revolution) that existed until recently, have now lost their relevance. Today, absolute uncertainty hangs over the future. The inability to predict the future poses certain challenges to the present. The end of any teleology of history imposes on the present a debt of memory. Features of the life of memory, the specifics of its state and functioning directly affect the state of identity, both personal and collective. Distortion of memory, its incorrect work, and its ideological manipulation can give rise to an identity crisis. The memorial phenomenon is a certain political resource in a situation of severe socio-political breaks and changes. In the conditions of the economic crisis and in the absence of a real and clear program for future development, the state often seeks to turn memory into the main element of national consolidation.

A Short Life of Kierkegaard

2013 ◽  
Author(s):  
Walter Lowrie ◽  
Alastair Hannay
Keyword(s):  
Old Testament ◽  
Soren Kierkegaard ◽  
The State ◽  
Young Girl ◽  
Love Affair ◽  
Short Life ◽  
The Past ◽  
Modern Thought ◽  
Hans Christian Andersen

A small, insignificant-looking intellectual with absurdly long legs, Søren Kierkegaard (1813–1855) was a veritable Hans Christian Andersen caricature of a man. A strange combination of witty cosmopolite and melancholy introvert, he spent years writing under a series of fantastical pseudonyms, lavishing all the splendor of his mind on a seldom-appreciative world. He had a tragic love affair with a young girl, was dominated by an unforgettable Old Testament father, fought a sensational literary duel with a popular satiric magazine, and died in the midst of a violent quarrel with the state church for which he had once studied theology. Yet this iconoclast produced a number of brilliant books that have profoundly influenced modern thought. This classic biography presents a charming and warmly appreciative introduction to the life and work of the great Danish writer. It tells the story of Kierkegaard's emotionally turbulent life with a keen sense of drama and an acute understanding of how his life shaped his thought. The result is a wonderfully informative and entertaining portrait of one of the most important thinkers of the past two centuries.

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