Deciphering the role of meteorological parameters controlling the sediment load and water discharge in the Sutlej basin, Western Himalaya

2021 ◽  
Vol 298 ◽  
pp. 113413
Author(s):  
Prem Kumar ◽  
Chandra Shekhar Dubey ◽  
Om Kumar ◽  
Shashank Shekhar ◽  
D.P. Shukla ◽  
...  
2021 ◽  
pp. 1111-1114
Author(s):  
T.G. Potemkina ◽  
◽  
V.L. Potemkin ◽  

Abstract. The sediment load delivery into Lake Baikal from its main tributaries the Selenga, Upper Angara, and Barguzin Rivers has been reduced since the mid-1970s. This is explained by climate change and socioeconomic activities. Integrated analysis of changes in hydro-meteorological parameters (water discharge, sediment load, air temperature, precipitation) and their trends over the period 1946 1975 (baseline) and 1976 2017 (warming) is performed. Changes in natural processes and human activity were negligible during the baseline period. During the warming period, the greatest reduction of the sediment load inflow against the background of temperature rise and precipitation decrease occurred in the interval between 1996 and 2017 in the Selenga River, between 1985 and 2017 in the Upper Angara River, and between 1992 and 2017 in the Barguzin River. The flux of the sediment load into these rivers was 768 103, 88 103, and 29 103 t y 1, respectively. This is 2 3 times less than the average multiyear values for all period of 1946 2017, which are usually used when characterizing sediment load runoff from these rivers. Currently the values in the given intervals correspond to the actual sediment load flux into Lake Baikal from the main tributaries.


2017 ◽  
Author(s):  
Hendrik Andersen ◽  
Jan Cermak ◽  
Julia Fuchs ◽  
Reto Knutti ◽  
Ulrike Lohmann

Abstract. The role of aerosols, clouds and their interactions with radiation remain among the largest unknowns in the climate system. Even though the processes involved are complex, aerosol-cloud interactions are often analyzed by means of bivariate relationships. In this study, 15 years (2001–2015) of monthly satellite-retrieved nearly-global aerosol products are combined with reanalysis data of various meteorological parameters to predict satellite-derived marine liquid-water cloud occurrence and properties by means of regionally-specific artificial neural networks. The statistical models used are shown to be capable of predicting clouds, especially in regions of high cloud variability. At this monthly scale, lower tropospheric stability is shown to be the main determinant of cloud fraction and droplet size, especially in stratocumulus regions, while boundary layer height controls the liquid-water amount and thus the optical thickness of clouds. While aerosols show the expected impact on clouds, at this scale they are less relevant than some meteorological factors. Global patterns of the derived sensitivities point to regional characteristics of aerosol and cloud processes.


The correct assessment of amount of sediment during design, management and operation of water resources projects is very important. Efficiency of dam has been reduced due to sedimentation which is built for flood control, irrigation, power generation etc. There are traditional methods for the estimation of sediment are available but these cannot provide the accurate results because of involvement of very complex variables and processes. One of the best suitable artificial intelligence technique for modeling this phenomenon is artificial neural network (ANN). In the current study ANN techniques used for simulation monthly suspended sediment load at Vijayawada gauging station in Krishna river basin, Andhra Pradesh, India. Trial & error method were used during the optimization of parameters that are involved in this model. Estimation of suspended sediment load (SSL) is done using water discharge and water level data as inputs. The water discharge, water level and sediment load is collected from January 1966 to December 2005. This approach is used for modelled the SSL. By considering the results, ANN has the satisfactory performance and more accurate results in the simulation of monthly SSL for the study location.


Author(s):  
Mirela Voiculescu ◽  
Daniel-Eduard Constantin ◽  
Simona Condurache-Bota ◽  
Valentina Călmuc ◽  
Adrian Roșu ◽  
...  

The main purpose of this study was to investigate whether meteorological parameters (temperature, relative humidity, direct radiation) play an important role in modifying the NO2 concentration in an urban environment. The diurnal and seasonal variation recorded at a NO2 traffic station was analyzed, based on data collected in situ in a Romanian city, Braila (45.26° N, 27.95° E), during 2009–2014. The NO2 atmospheric content close to the ground had, in general, a summer minimum and a late autumn/winter maximum for most years. Two diurnal peaks were observed, regardless of the season, which were more evident during cold months. Traffic is an important contributor to the NO2 atmospheric pollution during daytime hours. The variability of in situ measurements of NO2 concentration compared relatively well with space-based observations of the NO2 vertical column by the Ozone Monitoring Instrument (OMI) satellite for most of the period under scrutiny. Data for daytime and nighttime (when the traffic is reduced) were analyzed separately, in the attempt to isolate meteorological effects. Meteorological parameters are not fully independent and we used partial correlation analysis to check whether the relationships with one parameter may be induced by another. The correlation between NO2 and temperature was not coherent. Relative humidity and solar radiation seemed to play a role in shaping the NO2 concentration, regardless of the time of day, and these relationships were only partially interconnected.


Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1409 ◽  
Author(s):  
Hye Won Lee ◽  
Yong Seok Lee ◽  
Jonggun Kim ◽  
Kyoung Jae Lim ◽  
Jung Hyun Choi

Sediment plays an important role in the water quality of a lake by acting as both a nutrient source and sink. The amount of phosphorus and nitrogen in the water depends on the internal load from the sediment as well as the external load. To estimate the effects of sediment load on the water quality of a reservoir, we applied a three-dimensional hydrodynamic and transport model based on the benthic chamber experimental results at Euiam Lake, South Korea. As shown in the sensitivity analysis results, the eutrophication period could be significantly extended by a change of phosphorus flux rates from the sediments. The increased phosphorus flux from the sediments intensifies the algal growth of Euiam Lake, which could cause serious algal bloom during spring and fall. This study provides information on nutrient concentrations in the sediment of Euiam Lake, verifies the role of the sediment as a source or sink of nutrients, and evaluates the effect of sediment release of nutrients and contaminants on water quality. This research is a useful tool in determining the effects of internal load in lakes and establishing the operation guideline for sediment management in order to maintain feasible water quality for beneficial use.


2017 ◽  
Vol 3 (01) ◽  
pp. 07-13
Author(s):  
Vertika Shukla ◽  
Rajesh Bajpai ◽  
Manoj Semwal ◽  
D. K. Upreti

In recent years there has been growing interest in the study on lichen diversity with relation to altitudinal gradient and anthropogenic disturbances , as changes in lichen community composition may indicate air quality and microclimatic changes. The altitudinal data of species diversity and its subsequent changes with respect to time and space may provide vital information regarding impact of air pollution and/or climate change at regional or global scales. Chopta-Tungnath and adjoining areas of Garhwal Himalaya provide habitat and ecological variation with range of altitude lying between 300 to 3000 m. Out of the 116 species of lichens known from the studied area, the highest species diversity was observed between altitudes 1800 to 2100 m. Lichen communities occurring between 600–1800 m were dominated by members of Physciaceae, while Parmeliaceae were most common above 1800 m. Altitude beyond 2100 m experiences high precipitation, varying temperature conditions and increased incident UV radiation, which are responsible for controlling the variability in lichen diversity to a great extent in the region. The diversity of secondary metabolites in lichen species and consequent changes in species composition at various altitudes indicate the association of secondary chemicals in conferring the lichens resistance to biotic and abiotic stresses. The correlations of lichen diversity, secondary metabolites and the altitudes at which the lichens are growing, present suggestive role of secondary metabolites in determining species composition and sustainability in different environmental conditions.


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