Evidence for brown carbon absorption over the Bay of Bengal during the southwest monsoon season: a possible oceanic source

2020 ◽  
Vol 22 (8) ◽  
pp. 1743-1758
Author(s):  
Poonam Bikkina ◽  
Srinivas Bikkina ◽  
Kimitaka Kawamura ◽  
A. K. Sudheer ◽  
G. Mahesh ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Sea Salt ◽  
Brown Carbon ◽  
Aerosol Radiative Forcing ◽  
Carbon Absorption ◽  
Salt Component ◽  
Carbon Aerosols ◽  
Southwest Monsoon Season

Light-absorbing brown carbon aerosols can have a marine origin over the coastal oceans and are likely associated with the sea salt component emitted from the ocean surface – significantly contributes to aerosol radiative forcing.

scholarly journals Beaching patterns of plastic debris along the Indian Ocean rim

2020 ◽  
Author(s):  
Mirjam van der Mheen ◽  
Erik van Sebille ◽  
Charitha Pattiaratchi
Keyword(s):  
Indian Ocean ◽  
Bay Of Bengal ◽  
Plastic Material ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Plastic Waste ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
The Indian Ocean ◽  
Southwest Monsoon Season

Abstract. A large percentage of global ocean plastic waste enters the northern hemisphere Indian Ocean (NIO). Despite this, it is unclear what happens to buoyant plastics in the NIO. Because the subtropics in the NIO is blocked by landmass, there is no subtropical gyre and no associated subtropical garbage patch in this region. We therefore hypothesise that plastics "beach" and end up on coastlines along the Indian Ocean rim. In this paper, we determine the influence of beaching plastics by applying different beaching conditions to Lagrangian particle tracking simulation results. Our results show that a large amount of plastic likely ends up on coastlines in the NIO, while some crosses the equator into the southern hemisphere Indian Ocean (SIO). In the NIO, the transport of plastics is dominated by seasonally reversing monsoonal currents, which transport plastics back and forth between the Arabian Sea and the Bay of Bengal. All buoyant plastic material in this region beaches within a few years in our simulations. Countries bordering the Bay of Bengal are particularly heavily affected by plastics beaching on coastlines. This is a result of both the large sources of plastic waste in the region, as well as ocean dynamics which concentrate plastics in the Bay of Bengal. During the intermonsoon period following the southwest monsoon season (September, October, November), plastics can cross the equator on the eastern side of the NIO basin into the SIO. Plastics that escape from the NIO into the SIO beach on eastern African coastlines and islands in the SIO or enter the subtropical SIO garbage patch.

scholarly journals Intra-seasonal oscfffations of radio refractive index during southwest monsoon over India

MAUSAM ◽  
2022 ◽  
Vol 44 (3) ◽  
pp. 271-276
Author(s):  
H. N. SRIVASTAVA ◽  
K. C. SINHARAY ◽  
R. K. MUKHOPADHYAY
Keyword(s):  
Refractive Index ◽  
Monsoon Season ◽  
Temporal Variations ◽  
Southwest Monsoon ◽  
The Individual ◽  
Southwest Monsoon Season ◽  
Seasonal Oscillations ◽  
Refractive Index Data ◽  
Indian Seas ◽  
Variance Explained

The study deals with the spatial and temporal variations of intra-seasonal oscillations in radio refractive index during southwest monsoon season over India and islands over Indian seas. Average daily radio refractive index data from 1 June to 30 September and that of the individual years for the period 1969-1986 were subjected to harmonic analysis to investigate the contributions of various periodicities in monsoon radio refractive index. The inter-annual variability of various intra-seasonal oscillations have been studied for each 5° latitudinal strip from 50 oN to 30° N with the help of variance explained by various frequency modes for different years. Variance explained by 30-60 day and 10-20 day modes were studied in relation to monsoon performance.   The northward and eastward propagation of30.60 day mod~ was noticed. The 10.20 day mode and seasonal mode dominate at latitudinal belts 5°N.10oN and 25°N-30°N respectively. Between 10°N and 25°N, both 30-60 day and 10-20 day modes occur.  

Soil Quality Near Indian Oil Corporation Limited Pol Depot Ahmednagar, Maharashtra, State of India

2019 ◽  
pp. 168-178
Author(s):  
Kanchan P. Rathoure
Keyword(s):  
Water Quality ◽  
Soil Quality ◽  
Monsoon Season ◽  
Southwest Monsoon ◽  
Soil Types ◽  
Central Position ◽  
The West ◽  
Deccan Plateau ◽  
Southwest Monsoon Season ◽  
Godavari Basin

The area in question has diversified relief and amount of rainfall and soil types. It is dry region lies in east, irrigated region in north and tribal-dominant population dominant in the west. Ahmednagar district is situated partly in the upper Godavari basin and partly in the Bhīma basin occupying a somewhat central position in Maharashtra state. The climate of the district is characterized by a hot summer and general dryness throughout the year except during the southwest monsoon season (i.e., June to September). Physiographically the district forms part of Deccan Plateau. Part of Sahayadri hill ranges fall in the district. Here in this chapter, the author has elaborated about soil quality and ground water quality near IOCL Terminal Ahmednagar, Maharashtra, India.

scholarly journals Seasonal intercomparison of observational rainfall datasets over India during the southwest monsoon season

2014 ◽  
Vol 35 (9) ◽  
pp. 2326-2338 ◽  
Author(s):  
Satya Prakash ◽  
Ashis K. Mitra ◽  
Imran M. Momin ◽  
E. N. Rajagopal ◽  
S. Basu ◽  
...  
Keyword(s):  
Monsoon Season ◽  
Southwest Monsoon ◽  
Southwest Monsoon Season

Experimental evidence of the lensing effect suppression for atmospheric black carbon containing brown coatings

2020 ◽  
Author(s):  
Vaios Moschos ◽  
Martin Gysel-Beer ◽  
Robin L. Modini ◽  
Joel C. Corbin ◽  
Dario Massabò ◽  
...  
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
Wavelength Dependence ◽  
Chem Phys ◽  
Absorption Enhancement ◽  
Visible Spectroscopy ◽  
Scanning Mobility Particle Sizer ◽  
Absorption Data ◽  
Brown Carbon ◽  
Aerosol Radiative Forcing

<p>Accounting for the wavelength- and source-dependent optical absorption properties of the abundant light-absorbing organic (brown) carbon (BrC) and the mixing state of atmospheric black carbon (BC) are essential to reduce the large uncertainty in aerosol radiative forcing. Estimation of BrC absorption online by subtraction is highly uncertain and may be biased if not decoupled from the potential BC absorption enhancement (lensing) due to non-refractory (organic and inorganic) coating acquisition.</p><p>Here, the reported total particulate absorption is based on long-term, filter-based seven-wavelength Aethalometer (AE33 model) data, corrected for multiple scattering effects with Multi-Wavelength Absorbance Analyzer (5λ MWAA) measurements. Using ultraviolet-visible spectroscopy absorbance measurements along with particle size distributions obtained by a scanning mobility particle sizer, we have conducted Mie calculations to assess the importance of source-specific extractable particulate BrC (Moschos et al., 2018) versus BC absorption.</p><p>For the species-specific optical closure, the wavelength dependence of bare BC absorption is estimated using MWAA measurements upon successive filter extractions to remove the influence of BrC/coatings. The lensing contribution, supported by observations from field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, is estimated at longer wavelengths using a refined proxy for the BC coating thickness. The approach is validated independently by applying a novel positive matrix factorization-based approach on the calibrated total AE33 absorption data.</p><p>Based on the observational constraints established in this study, we demonstrate for various distinct case studies that the interplay between lensing and BrC absorption results in lower than expected BC absorption at shorter wavelengths. This indicates that the volume additivity assumption is not valid for particulate absorption by internally mixed heterogeneous atmospheric aerosol populations. These comprehensive experimental analyses verify the BC lensing suppression predicted for simplified core-shell structures containing moderately absorbing BrC (Lack & Cappa, 2010). The implications discussed in this work are relevant for co-emitted species from biomass burning or aged plumes with high BrC to BC mass/absorption ratio.</p><p> </p><p><strong>References</strong></p><p>Moschos, V., Kumar, N. K., Daellenbach, K. R., Baltensperger, U., Prévôt, A. S. H., and El Haddad, I.: Source apportionment of brown carbon absorption by coupling ultraviolet-visible spectroscopy with aerosol mass spectrometry, Environ. Sci. Tech. Lett., 5, 302-308, https://doi.org/10.1021/acs.estlett.8b00118, 2018.</p><p>Lack, D. A. and Cappa, C. D.: Impact of brown and clear carbon on light absorption enhancement, single scatter albedo and absorption wavelength dependence of black carbon, Atmos. Chem. Phys., 10, 4207–4220, https://doi.org/10.5194/acp-10-4207-2010, 2010.</p>

scholarly journals NGHIÊN CỨU XU THẾ BIẾN ĐỘNG TRƯỜNG NHIỆT ĐỘ BỀ MẶT BIỂN VÀ ẢNH HƯỞNG CỦA ENSO ĐẾN VÙNG BIỂN TÂY NAM VIỆT NAM SỬ DỤNG DỮ LIỆU VIỄN THÁM VÀ GIS

2020 ◽  
Vol 20 (2) ◽  
pp. 129-141
Author(s):  
Tran Anh Tuan ◽  
Vu Hai Dang ◽  
Pham Viet Hong ◽  
Do Ngoc Thuc ◽  
Nguyen Thuy Linh ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Monsoon Season ◽  
Linear Regression Analysis ◽  
Southwest Monsoon ◽  
Sea Surface ◽  
Northeast Monsoon ◽  
Temperature Trends ◽  
Sea Surface Temperature Anomalies ◽  
Southwest Monsoon Season

In this article, the sea surface temperature trends and the influence of ENSO on the southwest sea of Vietnam were analyzed using the continuous satellite-acquired data sequence of SST in the period of 2002–2018. GIS and average statistical methods were applied to calculate the average monthly and seasonal sea surface temperature, the seasonal sea surface temperature anomalies for each year and for the whole study period. Subsequently, the changing trends of sea surface temperature in the northeast and southwest monsoon seasons were estimated using linear regression analysis. Research results indicated that the sea surface temperature changed significantly throughout the calendar year, in which the maximum and minimum sea surface temperature are 31oC in May and 26oC in January respectively. Sea surface temperature trends range from 0oC/year to 0.05oC/year during the Northeast monsoon season and from 0.025oC/year to 0.055oC/year during the southwest monsoon season. Results based on the Oceanic Niño Index (ONI) analysis also show that the sea surface temperature in the study area and adjacent areas is strongly influenced and significantly fluctuates during El Niño and La Niña episodes.

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