Simulation of the Hydrodynamic Field in Nhat Le Estuary, Quang Binh Province

Hydrodynamic field is the primary research problem of all studies on coastal estuarine areas. Over the years, there have been many studies on Nhat Le estuary's region (Quang Binh). Still, these studies have not focused on simulating the characteristics of the hydrodynamics of this area. This study will present the ability to apply a mathematical model to simulate hydrodynamic fields for the region of Nhat Le estuary and Quang Binh sea by constructing the MIKE 21 model set based on the actual measurement database by the Center for Environmental Fluid Dynamics implemented in 2018. Through the calculation scenarios under different conditions, the longshore current mainly consists of Southeast - Northwest (especially with NE waves, the current direction is Northwest - Southeast) with current speed mostly in the range of 0.1 - 0.4 m/s. In estuarine areas, river flows have complicated developments, including many component flows. In the dry season, the river flow is not strong and is dominated by changes in the tide phase, withdrawal in a day. There are days of high flood flow in the flood season, overwhelming the tidal currents; the maximum flow velocity at the door can reach more than 6 m/s. Waves in the southwest monsoon season are relatively small, about 0.25 - 0.6 m; while the waves in the Northeast monsoon season are quite large and very strong during the storm, but when the depth is about -3 to -4 m, the wave height decreases sharply, spreading to the door. In particular, when there are floods in the river, the waves that propagate through this depth will almost calm.

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SPATIO-TEMPORAL ESTIMATION OF INTEGRATED WATER VAPOUR OVER THE MALAYSIAN PENINSULA DURING MONSOON SEASON

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-4-w5-165-2017 ◽

2017 ◽

Vol XLII-4/W5 ◽

pp. 165-175

Author(s):

S. Salihin ◽

T. A. Musa ◽

Z. Mohd Radzi

Keyword(s):

Water Vapour ◽

Monsoon Season ◽

Temporal Distribution ◽

Southwest Monsoon ◽

Northeast Monsoon ◽

Path Delay ◽

Zenith Path Delay ◽

Temporal Estimation ◽

Integrated Water Vapour ◽

Spatio Temporal

This paper provides the precise information on spatial-temporal distribution of water vapour that was retrieved from Zenith Path Delay (ZPD) which was estimated by Global Positioning System (GPS) processing over the Malaysian Peninsular. A time series analysis of these ZPD and Integrated Water Vapor (IWV) values was done to capture the characteristic on their seasonal variation during monsoon seasons. This study was found that the pattern and distribution of atmospheric water vapour over Malaysian Peninsular in whole four years periods were influenced by two inter-monsoon and two monsoon seasons which are First Inter-monsoon, Second Inter-monsoon, Southwest monsoon and Northeast monsoon.

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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

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/20/2/14173 ◽

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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Blue whales off the Southern coast of Sri Lanka during the Southwest Monsoon Season

J. Cetacean Res. Manage. ◽

10.47536/jcrm.v21i1.189 ◽

2020 ◽

Vol 21 (1) ◽

pp. 1-7

Author(s):

Grace Russell ◽

Marcus Bridge ◽

Maja Nimak-Wood

Keyword(s):

Sri Lanka ◽

Monsoon Season ◽

Weather Conditions ◽

Southwest Monsoon ◽

Lower Latitude ◽

Northeast Monsoon ◽

Southern Coast ◽

Northern India ◽

Blue Whales ◽

Southwest Monsoon Season

Observations of 37 individual blue whales (Balaenoptera musculus) were recorded off the southern coast of Sri Lanka during the Southwest Monsoon Season (SWM). Sightings were made during a scientific geophysical survey campaign conducted in July and August 2017. Whilst blue whales are regularly recorded on the continental slope of southern Sri Lanka during the Northeast Monsoon Season (NEM) (December - March) and during the two inter-monsoonal periods (March - April and September - October), limited data is available for the SWM (May - September) mostly due to unfavourable weather conditions and very little survey effort. In the northern hemisphere blue whales undertake seasonal migrations from higher latitude feeding grounds to lower latitude breeding and wintering areas. However it has been suggested that a population of blue whales in the Northern India Ocean (NIO) remains in lower latitudes year round taking advantage of the rich upwelling areas off Somalia, southwest Arabia and western Sri Lanka. Data from this study nevertheless support a theory that a certain number of individuals remain off the southern coast off Sri Lanka during the SWM, suggesting that the productivity in this region is sufficient to support their year-round presence. This study therefore fills a knowledge gap regarding the presence and movement of blue whales in the NIO highlighting the importance of data obtained from platforms of opportunity.

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Inter and intra-seasonal, variation of thermodynamic parameters of the atmosphere over coastal Tamilnadu during northeast monsoon

MAUSAM ◽

10.54302/mausam.v47i3.3740 ◽

2021 ◽

Vol 47 (3) ◽

pp. 259-268

Author(s):

Y.E. A. RAJ

Keyword(s):

Water Content ◽

Liquid Water ◽

Monsoon Season ◽

Moisture Flux ◽

Liquid Water Content ◽

Southwest Monsoon ◽

Northeast Monsoon ◽

Thermodynamic Structure ◽

Clear Sign ◽

Analysis Of Variation

The thermodynamic structure of the atmosphere over coastal Tamilnadu during the northeast monsoon season has been studied in detail based on the daily 0000 UTC upper air data between 1000 and 500 hPa levels of Madras for October-January for the l0 year period 1976-77 to 1985-86. Normal upper air soundings have been computed for dry and wet spells of northeast monsoon and for the brief period of southwest monsoon prior to northeast monsoon onset. The moisture flux crossing Madras and the liquid water content over Madras have been computed for various categories of monsoon activity. It has been shown that the onset of easterlies over Madras is accompanied by a cooling of 1C of the atmosphere over Madras at all levels upto 500 hPa. An east to west moisture flux of 21.1 x 108 metric tons per day across one degree wall over Madras has been found to cross coast during typical wet spell of northeast monsoon. The moisture flux crossing coast for good northeast monsoon and also the normal flux computed for the period of study compared fairly well with the moisture flux crossing west coast during southwest monsoon obtained in various other studies. The energy of an air column over coastal Tamilnadu was found to decrease subsequent to the onset of northeast monsoon. Analysis of variation of liquid water content revealed that even during deficit rainfall years there was considereable amount of low level moisture in the atmosphere. Neither during dryspells of northeast monsoon nor after its retreat was there any clear sign of spreading of continental air mass over coastal Tamilnadu.

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An analytical study of easterly waves over southern peninsular India during the northeast monsoon 2010

MAUSAM ◽

10.54302/mausam.v65i4.1243 ◽

2021 ◽

Vol 65 (4) ◽

pp. 591-602

Author(s):

B. GEETHA ◽

S. BALACHANDRAN

Keyword(s):

Monsoon Season ◽

Wave Radiation ◽

Northeast Monsoon ◽

Peninsular India ◽

Upper Troposphere ◽

Easterly Waves ◽

Easterly Wave ◽

Time Period ◽

Meridional Winds ◽

The Waves

Easterly wave characteristics over southern peninsular India during the northeast monsoon season of 2010 are examined by means of synergetic analysis involving synoptic, statistical and numerical methods. NCEP 6-hourly reanalysis datasets of zonal and meridional winds, vertical velocity, temperature and net long wave radiation at 2.5° × 2.5° grid resolution for the period 20th October to 31st December, 2010 form the main database for the analysis. During this period, 3 easterly waves could be identified to have passed over this region and the time period of these waves are determined to be 4.2 days (4.5 days) by statistical methods (synoptic methods). The speed of movement, wavelength and amplitude of the waves are determined to be 7.28 ms-1, 2800 km and 6.7 ms-1 respectively. While rising motion is observed at most of the tropospheric levels over and behind the trough, subsidence occurs ahead of the trough. Divergence is noted over and behind the trough at upper troposphere while convergence occurs in the lower to mid-troposphere. Concomitantly warming is noted ahead of the trough while colder anomalies are noted in the lower levels over and behind the trough.

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Simulation of spatial variation of plankton communities in the South Central Vietnam sea by ROMS model

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/19/3/11627 ◽

2019 ◽

Vol 19 (3) ◽

pp. 371-384

Author(s):

Vu Thi Vui

Keyword(s):

Monsoon Season ◽

Southwest Monsoon ◽

Ocean Modeling ◽

Northeast Monsoon ◽

The South ◽

Regional Ocean Modeling System ◽

Roms Model ◽

South Central ◽

Central Vietnam ◽

Plankton Communities

This study preliminarily applies the Regional Ocean Modeling System (ROMS) in the two major monsoon seasons (Northeast and Southwest monsoons) for the South Central Vietnam sea (9–14.5oN, 105–112oE), in which the hydrodynamic and ecological modules are coupled. The results show that the plankton only develop in 200 m water on the top, concentrated mainly in the 0–70 m layer and in maximum biomass of 15–40 m layer. In the Northeast monsoon season, the plankton are concentrated mainly in the northern part and open seas of the area, while in the Southwest monsoon season, they are concentrated in the upwelling and adjacent southern areas. These results correctly reflect the basic law of the development of plankton communities in the sea area.

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GOATFISH (MULLIDAE) RESOURCES IN VIETNAM SEA BASED ON BOTTOM TRAWL SURVEY IN THE PERIOD 2012 - 2013

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/17/4/11054 ◽

2018 ◽

Vol 17 (4) ◽

pp. 459-468

Author(s):

Vo Trong Thang ◽

Tran Van Cuong ◽

Mai Cong Nhuan ◽

Nguyen Van Hai

Keyword(s):

Monsoon Season ◽

Southwest Monsoon ◽

Current Status ◽

Total Output ◽

Total Biomass ◽

Trawl Survey ◽

Northeast Monsoon ◽

Fisheries Resources ◽

Bottom Fish ◽

Gulf Of Tonkin

During 2012 - 2013, under the project “The current status and movements of fisheries resources in Vietnam sea” two surveys were conducted to investigate bottom fish resources with 494 hauls. Based on the research results, 16 species belonging to 3 genera of goatfishes were analyzed. The goatfish output accounted for 0.34 - 4.31% compared to the total output of bottom fish in the survey time. The species Upeneus japonicus comprised 62 - 94% of the output of the goatfishes. The average exploitation yield of goatfishes in the Northeast monsoon season was 1.035 kg/h and that in the Southwest monsoon season was 1.446 kg/h. The exploitation yield had a tendency of decrease compared with the previous studies. The distribution density was the highest in the Southwestern region areas and the lowest in the Gulf of Tonkin; Meanwhile according to spatial distribution the density of goatfishes was the highest in the depth < 20 m and the lowest in the depth from 30 - 50 m. The estimation for the total biomass of goatfishes in the Northeast monsoon season was 13,450 tons and in the Southeast monsoon season was 15,321 tons.

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Northeast monsoon rainfall and agricultural production in Tamilnadu and Andhra PradeshI - Rainfall variability and its significance in agricultural production

MAUSAM ◽

10.54302/mausam.v64i2.687 ◽

2021 ◽

Vol 64 (2) ◽

pp. 309-316

Author(s):

R.P. SAMUI ◽

M.V. KAMBLE ◽

J.P. SABALE

Keyword(s):

Agricultural Production ◽

Andhra Pradesh ◽

Monsoon Rainfall ◽

Positive Impact ◽

Monsoon Season ◽

Rainfall Variability ◽

Southwest Monsoon ◽

Positive Trend ◽

Northeast Monsoon ◽

Northeast Monsoon Rainfall

ekWulwu Hkkjrh; vFkZO;oLFkk dk egRoiw.kZ ?kVd gS tks —f"k dks izR;{k% :i ls izHkkfor djrk gS D;ksafd ;g ,d pkSFkkbZ th-Mh-ih- vkSj —f"k ij fuHkZj 60 izfr’kr turk dh vkthfodk dks izHkkfor djrk gSA Hkkjr esa eq[;r% nf{k.k&if’peh ekWulwu +_rq ds nkSjku o"kkZ gksrh gSA Hkkjr esa vDrwcj ls fnlEcj ds nkSjku fo’ks"kdj iwohZ vkSj nf{k.kh jkT;ksa esa ekulwuksRrj vof/k] ftls mRrj iwohZ ekWulwu dgrs gS] esa Hkh dkQh o"kkZ gksrh gSA ;g o"kkZ —f"k ds fy, vkSj bu {ks=ksa ds lac) lsDVjksa ds fy, dkQh egRoiw.kZ gksrh gSA rfeyukMq ds iwohZ rVh; ftyksa esa nf{k.k ls mRrj rd o"kkZ esa o`f) dh izo`fRr dk irk pyk gSA blds foijhr vka/kz izns’k ds rVh; nf{k.k iwohZ ftyksa esa vf/kd vkSj mRrj iwohZ Hkkxksa esa o"kkZ esa deh dh izo`fRr dk irk pyk gSA vka/kz izns’k dh vis{kk rfeyukMq esa o"kkZ dh vf/kdrk ds dkj.k mRrj iwohZ ekulwu dk nf{k.k if’pe ekulwu o"kkZ dh rqyuk esa —f"k mRiknu ij vf/kd izHkko dk irk pyrk gSA —f"k mRiknu ij o"kkZ ds izHkko ds v/;;uksa ls vka/kz izns’k esa pkoy vkSj eDdk ds mRiknu esa mRrj iwohZ ekWulwu ds ldkjkRed izHkko dk irk pyk gSA eDdk dh mit esa yxkrkj ldkjkRed izo`fRr dk irk pyk gSA mRrj iwohZ ekulwu _rq ds nkSjku vka/kz izns’k ds rVh; ftyksa dh rqyuk esa rfeyukMq ds rVh; ftyksa esa pØokr ;k vonkc dh otg ls Hkkjh ls vf/kd Hkkjh o"kkZ vkSj ck<+ ds dkj.k mRiknu dh deh vkbZ gSA ifjofrZrk ds ckjs esa mfpr tkudkjh rFkk mRrj iwohZ ekulwu o"kkZ ds ekSleh iwokZuqeku ds lkFk&lkFk —f"k izpkyuksa ds fy, fofo/k uhfr;ksa dk fodkl djus ls bu {ks=ksa ds —f"k vkSj tylalk/ku lsDVjksa ds fy, fu.kZ; ysus esa egRoiw.kZ vuqiz;ksx Hkwfedk gksxhA Monsoon which directly impacts agriculture is an important component of Indian economy because it influences about a quarter of the GDP and livelihood of 60% of the population who depend on agriculture for their livelihood. India receives rainfall mainly during southwest monsoon season. A considerable rainfall also occurs in India during the post monsoon period called as northeast monsoon during October to December, particularly over eastern and southern states and this is of great significance in agriculture and allied sectors in these regions. Increasing trend of rainfall is noticed from south to north in eastern coastal districts of Tamilnadu. On the contrary, it is higher in coastal southeast districts with decreasing trend in northeast parts of Andhra Pradesh. NE monsoon shows greater impact on agricultural production due to its higher quantum of rainfall compared to that of southwest monsoon rain in Tamilnadu than that in Andhra Pradesh. Studies on impact of rainfall on agricultural production revealed positive impact of NE monsoon on rice and maize production in AP. Maize yield is found to exhibit a consistent positive trend. Loss in production due to heavy to very heavy rain and flooding associated with cyclone or depression was more prominent along the coastal districts of Tamilnadu than that in the coastal districts of Andhra Pradesh during northeast monsoon season. Proper understanding of the variability and developing diversified strategies for agricultural operations alongwith the seasonal prediction of northeast monsoon rainfall would have considerable application value for decision making in agriculture and water resource sectors of these regions.

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MONSOON SEASON (June - September 2019)

MAUSAM ◽

10.54302/mausam.v71i3.55 ◽

2021 ◽

Vol 71 (3) ◽

pp. 523-552

Author(s):

Editor Mausam

Keyword(s):

Monsoon Season ◽

Central India ◽

Southwest Monsoon ◽

Andaman Sea ◽

Northeast Monsoon ◽

Madden Julian Oscillation ◽

Large Excess ◽

Positive Indian Ocean Dipole ◽

Entire Country ◽

Northwest India

The rainfall over the country as a whole during the monsoon season (June-September) was 110% of its Long Period Average (LPA) and thus categorized as a normal* monsoon year. Seasonal rainfall over Central India region (1263.2 mm) was large excess with 129% of LPA rainfallwhich was third highest since 1901 after the years 1994 (1311.3 mm) and 1961 (1297 mm) for the broad geographical region of Central India. Rainfall over South Peninsula (116% of LPA) region was excess, over Northwest India (99% of LPA) was normal and East and Northeast Region remained deficient at 88% of LPA. Southwest monsoon reached parts over the Andaman Sea on 18 May, two days earlier than its normal date. However, it set in over Kerala on 8 June, 7 days later than its normal date and covered the entire country by 19 July with a delay of 4 days. Typically, the monsoon current begins to withdraw around 1 September, with the retreat completed by 15 October. This year, the retreat began on 9 October, marking the longest ever delay and was complete by 16 October in just 8 days. The withdrawal of Southwest monsoon from the entire country and the commencement of the Northeast monsoon rains occurred simultaneously on 16 October. Sometimes there is a gap of 10 days between the two seasons. Due to neutral ENSO conditions and weak Madden Julian Oscillation (MJO), their influence on the monsoon were nearly absent especially in the second half of the season. Positive Indian Ocean Dipole (IOD) episode was observed since the beginning of the monsoon season and its rapid strengthening to the strongest ever was observed by mid of the monsoon season.

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Annual variations of carbonaceous PM<sub>2.5</sub> in Malaysia: influence by Indonesian peatland fires

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-22419-2015 ◽

2015 ◽

Vol 15 (16) ◽

pp. 22419-22449 ◽

Cited By ~ 2

Author(s):

Y. Fujii ◽

S. Tohno ◽

N. Amil ◽

M. T. Latif ◽

M. Oda ◽

...

Keyword(s):

Organic Compounds ◽

Biomass Burning ◽

Vanillic Acid ◽

Monsoon Season ◽

Chemical Species ◽

Principal Component ◽

Southwest Monsoon ◽

Northeast Monsoon ◽

Mass Ratio ◽

Southwest Monsoon Season

Abstract. In this study, we quantified carbonaceous PM2.5 in Malaysia through annual observations of PM2.5, focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon (EC) and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and cholesterol. The average concentrations of OP, LG, MN, galactosan, VA and cholesterol were higher during the southwest monsoon season (June–September) than during the northeast monsoon season (December–March), and these differences were statistically significant. Conversely, the syringaldehyde concentration during the southwest monsoon season was lower. The PM2.5 OP/OC4 mass ratio allowed distinguishing the seven samples, which have been affected by the Indonesian peatland fires (IPFs). In addition, we observed significant differences in the concentrations between the IPF and other samples of many chemical species. Thus, the chemical characteristics of PM2.5 in Malaysia appeared to be significantly influenced by IPFs during the southwest monsoon season. Furthermore, we evaluated two indicators, the vanillic acid/syringic acid (VA/SA) and LG/MN mass ratios, which have been suggested as indicators of IPFs. The LG/MN mass ratio ranged from 14 to 22 in the IPF samples and from 11 to 31 in the other samples. Thus, the respective variation ranges partially overlapped. Consequently, this ratio did not satisfactorily reflect the effects of IPFs in Malaysia. In contrast, the VA/SA mass ratio may serve as a good indicator, since it significantly differed between the IPF and other samples. However, the OP/OC4 mass ratio provided more remarkable differences than the VA/SA mass ratio, offering an even better indicator. Finally, we extracted biomass burning emissions' sources such as IPF, softwood/hardwood burning and meat cooking through varimax-rotated principal component analysis.

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