Spatial variation in fluvial hydraulics with major bed erosion zone: a study of Kharsoti river of India in the post monsoon period

2017 ◽  
Vol 10 (20) ◽  
Author(s):  
Md Kutubuddin Dhali ◽  
Mehebub Sahana
Keyword(s):  
Spatial Variation ◽  
Monsoon Period ◽  
Fluvial Hydraulics ◽  
Post Monsoon ◽  
Bed Erosion ◽  
Erosion Zone

scholarly journals Observations of Winter Ablation on Glaciers in the Mount Everest Region in 2020–2021

2021 ◽  
Vol 13 (14) ◽  
pp. 2692
Author(s):  
Mauri Pelto ◽  
Prajjwal Panday ◽  
Tom Matthews ◽  
Jon Maurer ◽  
L. Baker Perry
Keyword(s):  
Remote Sensing Data ◽  
Time Data ◽  
Mount Everest ◽  
Monsoon Period ◽  
National Geographic ◽  
Freezing Level ◽  
Post Monsoon ◽  
Base Camp ◽  
Dry Conditions ◽  
The Impact

Recent observations of rising snow lines and reduced snow-covered areas on glaciers during the October 2020–January 2021 period in the Nepal–China region of Mount Everest in Landsat and Sentinel imagery highlight observations that significant ablation has occurred in recent years on many Himalayan glaciers in the post-monsoon and early winter periods. For the first time, we now have weather stations providing real-time data in the Mount Everest region that may sufficiently transect the post-monsoon snow line elevation region. These sensors have been placed by the Rolex National Geographic Perpetual Planet expedition. Combining in situ weather records and remote sensing data provides a unique opportunity to examine the impact of the warm and dry conditions during the 2020 post-monsoon period through to the 2020/2021 winter on glaciers in the Mount Everest region. The ablation season extended through January 2021. Winter (DJF) ERA5 reanalysis temperature reconstructions for Everest Base Camp (5315 m) for the 1950–February 2021 period indicate that six days in the January 10–15 period in 2021 fell in the top 1% of all winter days since 1950, with January 13, January 14, and January 12, being the first, second, and third warmest winter days in the 72-year period. This has also led to the highest freezing levels in winter for the 1950–2021 period, with the January 12–14 period being the only period in winter with a freezing level above 6000 m.

scholarly journals Comparison of MODIS and AERONET derived aerosol optical depth over the Ganga Basin, India

2005 ◽  
Vol 23 (4) ◽  
pp. 1093-1101 ◽  
Author(s):  
S. N. Tripathi ◽  
Sagnik Dey ◽  
A. Chandel ◽  
S. Srivastava ◽  
Ramesh P. Singh ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Time Window ◽  
Absolute Error ◽  
Absolute Difference ◽  
Ganga Basin ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Dust Loading ◽  
The Absolute

Abstract. The Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS Terra measures global aerosol optical depth and optical properties since 2000. MODIS aerosol products are freely available and are being used for numerous studies. In this paper, we present a comparison of aerosol optical depth (AOD) retrieved from MODIS with Aerosol Robotic Network (AERONET) data for the year 2004 over Kanpur, an industrial city lying in the Ganga Basin in the northern part of India. AOD retrieved from MODIS (τaMODIS) at 0.55µm wavelength has been compared with the AERONET derived AOD (τaAERONET), within an optimum space-time window. Although the correlation between τaMODIS and τaAERONET during the post-monsoon and winter seasons (R2~0.71) is almost equal to that during the pre-monsoon and monsoon seasons (R2~0.72), MODIS is found to overestimate AOD during the pre-monsoon and monsoon period (characterized by severe dust loading) and underestimate during the post-monsoon and winter seasons. The absolute difference between τaMODIS and τaAERONET is found to be low (0.12±0.11) during the non-dust loading season and much higher (0.4±0.2) during dust-loading seasons. The absolute error in τaMODIS is found to be about ~25% of the absolute values of τaMODIS. Our comparison shows the importance of modifying the existing MODIS algorithm during the dust-loading seasons, especially in the Ganga Basin in northern part of India.

scholarly journals Influence of winds on temporally varying short and long period gravity waves in the near shore regions of Eastern Arabian Sea

2012 ◽  
Vol 9 (5) ◽  
pp. 3021-3047
Author(s):  
J. Glejin ◽  
V. Sanil Kumar ◽  
T. N. Balakrishnan Nair ◽  
J. Singh
Keyword(s):  
West Coast ◽  
Sea Breeze ◽  
Monsoon Period ◽  
West Coast Of India ◽  
Intermediate Period ◽  
Long Period ◽  
Post Monsoon ◽  
South West ◽  
South West Monsoon ◽  
West Monsoon

Abstract. Wave data collected off Ratnagiri, west coast of India during 1 May 2010 to 30 April 2012 is used in the study. Seasonal and annual variation in wave data controlled by the local wind system such as sea breeze and land breeze, and remote wind generated long period waves observed along the west coast of India, is studied. Sea breeze plays an important role in determining the sea state during pre and post monsoon seasons and the maximum wave height is observed during peak hours of sea breeze at 15:00 UTC. Long period waves (peak period over 13 s) are observed mainly during the pre and the post monsoon season. Maximum peak period observed during the study is 22 s and is in the month of October. Long period waves observed during the south west monsoon period of 2011 are identified as swell propagated from the Southern Ocean with an estimated travelling time of 5–6 days. The swells reaching the Arabian Sea from the South Indian Ocean and Southern Ocean, due to storms during the pre and post monsoon periods will modify the near surface winds, due to the dominant wave induced wind regime. Energy spectrum of observed waves indicates onset and decline of strong south west monsoon winds. Convergence of energy-containing frequency bands corresponding to short period waves (Tp < 8 s) and long period waves (Tp > 13 s) to intermediate period waves (8 < Tp < 13 s) are observed at the end of the pre monsoon season; divergence is observed during the start of the post monsoon period from intermediate period waves to short period waves and long period waves. South west monsoon period is characterized by the energy corresponding to the frequency band of intermediate period waves along the west coast of India.

scholarly journals Seasonal analysis of submicron aerosol in Old Delhi using high-resolution aerosol mass spectrometry: chemical characterisation, source apportionment and new marker identification

2021 ◽  
Vol 21 (13) ◽  
pp. 10133-10158
Author(s):  
James M. Cash ◽  
Ben Langford ◽  
Chiara Di Marco ◽  
Neil J. Mullinger ◽  
James Allan ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Mass Fraction ◽  
Crop Residue ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Crop Residue Burning ◽  
Waste Burning

Abstract. We present the first real-time composition of submicron particulate matter (PM1) in Old Delhi using high-resolution aerosol mass spectrometry (HR-AMS). Old Delhi is one of the most polluted locations in the world, and PM1 concentrations reached ∼ 750 µg m−3 during the most polluted period, the post-monsoon period, where PM1 increased by 188 % over the pre-monsoon period. Sulfate contributes the largest inorganic PM1 mass fraction during the pre-monsoon (24 %) and monsoon (24 %) periods, with nitrate contributing most during the post-monsoon period (8 %). The organics dominate the mass fraction (54 %–68 %) throughout the three periods, and, using positive matrix factorisation (PMF) to perform source apportionment analysis of organic mass, two burning-related factors were found to contribute the most (35 %) to the post-monsoon increase. The first PMF factor, semi-volatility biomass burning organic aerosol (SVBBOA), shows a high correlation with Earth observation fire counts in surrounding states, which links its origin to crop residue burning. The second is a solid fuel OA (SFOA) factor with links to local open burning due to its high composition of polyaromatic hydrocarbons (PAHs) and novel AMS-measured marker species for polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Two traffic factors were resolved: one hydrocarbon-like OA (HOA) factor and another nitrogen-rich HOA (NHOA) factor. The N compounds within NHOA were mainly nitrile species which have not previously been identified within AMS measurements. Their PAH composition suggests that NHOA is linked to diesel and HOA to compressed natural gas and petrol. These factors combined make the largest relative contribution to primary PM1 mass during the pre-monsoon and monsoon periods while contributing the second highest in the post-monsoon period. A cooking OA (COA) factor shows strong links to the secondary factor, semi-volatility oxygenated OA (SVOOA). Correlations with co-located volatile organic compound (VOC) measurements and AMS-measured organic nitrogen oxides (OrgNO) suggest SVOOA is formed from aged COA. It is also found that a significant increase in chloride concentrations (522 %) from pre-monsoon to post-monsoon correlates well with SVBBOA and SFOA, suggesting that crop residue burning and open waste burning are responsible. A reduction in traffic emissions would effectively reduce concentrations across most of the year. In order to reduce the post-monsoon peak, sources such as funeral pyres, solid waste burning and crop residue burning should be considered when developing new air quality policy.

scholarly journals The Response of Dissolved Organic Matter during Monsoon and Post-Monsoon Periods in the Regulated River for Sustainable Water Supply

2020 ◽  
Vol 12 (13) ◽  
pp. 5310
Author(s):  
Mei-Yan Jin ◽  
Hye-Ji Oh ◽  
Kyung-Hoon Shin ◽  
Min-Ho Jang ◽  
Hyun-Woo Kim ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Heavy Rainfall ◽  
Urban Land Use ◽  
Regulated River ◽  
Regulated Rivers ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Sustainable Water Supply

Dissolved organic matter (DOM) in rivers are an important factor in pollution management due to the abundance of stored carbon. Using fluorescent spectroscopy, we investigated the temporal and spatial dynamics of DOM compositions, as well as their properties, for two of the major four regulated rivers—Han River (HR) and Geum River (GR) in South Korea. We collected eight sampling sites, four from each of the two rivers (from close to the weirs) in order to observe the integrated effects of different land use (terrestrial input) during the monsoon (July) and post-monsoon periods (September). High integral values of DOM compositions (July: 30.81 ± 9.71 × 103 vs. September: 1.78 ± 0.66 × 103) were present in all eight sites after heavy rainfall during the monsoon period, which indicated that Asian monsoon climates occupy a potent role in the DOM compositions of the rivers. Regarding DOM compositions, tryptophan-like and fulvic acid-like components were predominant in HR and GR, especially in GR with high integral values of protein-like and humus components. However, the properties of terrestrial DOM between HR and GR are markedly different. These results considered due to the different land use, where the terrestrial DOM shows a low degree of humification due to a high percentage of agriculture and urban land use in GR. Furthermore, these two rivers are typical regulated rivers, due to their weir constructions. High values of DOM components were present in the downstream of the weirs; however, increasingly high patterns appeared in the HR because of heavy rainfall (511.01 mm in HR; 376.33 mm in GR). In addition, a lower increasing trend of humic-like component was present in the GR due to a low percentage of forest land use/cover. These results suggest that the effect of the weir on rivers can be highlighted by the different percentages of land use/cover under the conditions of the monsoon period. Hence, DOM fluorescence can serve as an effective indicator for providing an early signal for the complex impacts of the different land use and rainfall in the regulated river systems.

scholarly journals Groundwater Quality Assessment of Ambuliyar Watershed using GIS

2018 ◽  
Vol 7 (3.12) ◽  
pp. 491
Author(s):  
Keerthana Devi R ◽  
Balaji D ◽  
Natarajan H ◽  
Nasir N ◽  
Selvakumar R
Keyword(s):  
Tamil Nadu ◽  
Poor Quality ◽  
Public Works ◽  
Relative Importance ◽  
Chemical Parameters ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Geochemical Parameters ◽  
Gis Software ◽  
Physical And Chemical

Groundwater is significant in satisfying domestic and agricultural needs.Besides scarcity, the groundwater resource is degrading drastically around the world. The Ambuliyar watershed falling in parts of Tamil Nadu also faces similar problems. To decipher the quality degradation, pre-monsoon and post-monsoon data on various physical and chemical parameters was collected for 29 wells for the year 2014 from Public Works Department. Spatial maps were generated on the above geochemical parameters and categorized into five classes using GIS software. Weights were assigned for each parameter based on their relative importance in with each other parameters. Finally, quality index map was generated by integrating them, and subsequently their aerial extent in monsoons was worked out. During the post-monsoon period, 18% of the study area represents “excellent”, 46% “good”, 25% shows “moderate” and 11% shows “poor” quality. While during pre-monsoon period, 34% of the area exhibits “excellent”, 43% “ moderate”, and the remaining 23% of “poor”.    

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