scholarly journals Temporal and spatial patterns of abundance and occurrence of planktonic shrimps in the Songkhla Lagoon System, southern Thailand

2020 ◽  
Vol 96 (3) ◽  
pp. 521-538
Author(s):  
V Lheknim ◽  
R Yolanda
Keyword(s):  
Mesh Size ◽  
Southwest Monsoon ◽  
Water Levels ◽  
Salinity Range ◽  
Northeast Monsoon ◽  
Lagoon System ◽  
Significant Difference ◽  
Southern Thailand ◽  
Temporal And Spatial ◽  
Occurrence Patterns

Temporal and spatial distributions of planktonic shrimps from the hyperbenthos of Thale Sap and Thale Sap Songkhla lakes in the Songkhla Lagoon system, southern Thailand, were investigated using modified Riley push nets with a mesh size of 0.5 mm between June 2017 and June 2018. Three species of Mysida and two species of Dendrobranchiata shrimps were revealed, among which Nanomysis siamensis was dominant, representing more than 90% of the catch throughout the year. The Songkhla Lagoon system experiences extreme changes in temperature, salinity, pH, and water levels due to seasonal monsoons. A significant difference in the planktonic shrimp assemblages between Thale Sap and Thale Sap Songkhla was observed across the sampling months. Significant differences in the assemblage structure were also evident between Thale Sap and Thale Sap Songkhla and among sampling months. Dissimilar assemblage patterns were prominent temporally during the shift from southwest to northeast monsoon seasons and from the intermediate to southwest monsoon. Lake (Thale Sap or Thale Sap Songkhla) was the most important environmental parameter affecting occurrence patterns for N. siamensis, Mesopodopsis tenuipes, and Belzebub hanseni in the Songkhla Lagoon system. Salinity governed the spatial distribution of M. tenuipes and B. hanseni. Nanomysis siamensis was the only species that was regularly present in high abundance in Thale Sap and Thale Sap Songkhla over the entire salinity range. This suggest that N. siamensis is likely a resident species of the Songkhla Lagoon system.

scholarly journals Impact of Extreme Drought Climate on Water Security in North Borneo: Case Study of Sabah

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1135
Author(s):  
Carolyn Payus ◽  
Lim Ann Huey ◽  
Farrah Adnan ◽  
Andi Besse Rimba ◽  
Geetha Mohan ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resource ◽  
Supply And Demand ◽  
Water Security ◽  
Water Levels ◽  
Extreme Drought ◽  
Northeast Monsoon ◽  
Water Insecurity ◽  
The North ◽  
North Borneo

For countries in Southeast Asia that mainly rely on surface water as their water resource, changes in weather patterns and hydrological systems due to climate change will cause severely decreased water resource availability. Warm weather triggers more water use and exacerbates the extraction of water resources, which will change the operation patterns of water usage and increase demand, resulting in water scarcity. The occurrence of prolonged drought upsets the balance between water supply and demand, significantly increasing the vulnerability of regions to damaging impacts. The objectives of this study are to identify trends and determine the impacts of extreme drought events on water levels for the major important water dams in the northern part of Borneo, and to assess the risk of water insecurity for the dams. In this context, remote sensing images are used to determine the degree of risk of water insecurity in the regions. Statistical methods are used in the analysis of daily water levels and rainfall data. The findings show that water levels in dams on the North and Northeast Coasts of Borneo are greatly affected by the extreme drought climate caused by the Northeast Monsoon, with mild to the high risk recorded in terms of water insecurity, with only two of the water dams being water-secure. This study shows how climate change has affected water availability throughout the regions.

scholarly journals Human Impacts on Estuarine Erosion-Deposition in Southern Central Vietnam: Observation and Hydrodynamic Simulation

2021 ◽  
Vol 13 (15) ◽  
pp. 8303
Author(s):  
Vu Tuan Anh ◽  
Pham Ba Trung ◽  
Kim-Anh Nguyen ◽  
Yuei-An Liou ◽  
Minh-Thu Phan
Keyword(s):  
Deposition Process ◽  
Southwest Monsoon ◽  
North Coast ◽  
Northeast Monsoon ◽  
Southern Coast ◽  
Erosion Processes ◽  
The North ◽  
Central Vietnam ◽  
Southern Central ◽  
Deposition Processes

This paper aims to identify the causes and sources of erosion and deposition at small estuaries in southern central Vietnam under human intervention. The jetty built at the Tam Quan river mouth (Binh Dinh Province, Vietnam) serves as the base for the study. After its completion at the end of 2009, the hydrodynamic and erosion-deposition processes in the region have been significantly altered. Inside the estuary, the waves are not influenced, but the currents are increased during the ebb tide period and decreased during the flood tide timeframe. During the southwest monsoon, the jetty could cause an increase in the deposition process in both frequency and area, whereas the erosion process tends to narrow the area and increase the frequency on the north coast. In contrast, both deposition and erosion processes are increased on the southern coast. About 5859 m3 of sediments are deposited in the channel gate mainly by local sources. During the northeast monsoon, both deposition and erosion processes are located over a narrow area with frequency increased on the north coast, whereas the deposition process is narrowed with higher frequency on the southern coast. The total amount of sediment deposited at the estuary is 56,446 m3, of which 74.2% is from the onsite erosion material, 15.8% from the river and 10% from the longshore transportation. Generally, due to mainly erosion-deposition processes, sediment volume is accumulated during the northeast monsoon with amount 9.6 times more than that the southwest monsoon. The erosion-deposition processes are contributed to by poor practical management and local human activities inland and in the coastal regions, as well as the natural situation, resulting in serious impacts on society, the economy and the environment. Hence, the governance of the erosion-deposition processes and sediment load in small estuaries appear to contribute to the master plan for the local sustainable development of society and the economy.

scholarly journals Sensitivity Study of WRF Numerical Modeling for Forecasting Heavy Rainfall in Sri Lanka

Atmosphere ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 378 ◽  
Author(s):  
Channa Rodrigo ◽  
Sangil Kim ◽  
Il Jung
Keyword(s):  
Sri Lanka ◽  
Heavy Rainfall ◽  
Weather Prediction ◽  
Wrf Model ◽  
Heavy Rain ◽  
Heavy Precipitation ◽  
Sensitivity Study ◽  
Southwest Monsoon ◽  
Northeast Monsoon ◽  
Pressure System

This study aimed to determine the predictability of the Weather Research and Forecasting (WRF) model with different model physics options to identify the best set of physics parameters for predicting heavy rainfall events during the southwest and northeast monsoon seasons. Two case studies were used for the evaluation: heavy precipitation during the southwest monsoon associated with the simultaneous onset of the monsoon, and a low pressure system over the southwest Bay of Bengal that produced heavy rain over most of the country, with heavy precipitation associated with the northeast monsoon associated with monsoon flow and easterly disturbances. The modeling results showed large variation in the rainfall estimated by the model using the various model physics schemes, but several corresponding rainfall simulations were produced with spatial distribution aligned with rainfall station data, although the amount was not estimated accurately. Moreover, the WRF model was able to capture the rainfall patterns of these events in Sri Lanka, suggesting that the model has potential for operational use in numerical weather prediction in Sri Lanka.

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

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.

scholarly journals Projected changes in temperature and precipitation over mainland Southeast Asia by CMIP6 models

2021 ◽  
Author(s):  
S. Supharatid ◽  
J. Nafung ◽  
T. Aribarg
Keyword(s):  
Climate Change ◽  
Coupled Model ◽  
Southwest Monsoon ◽  
Future Climate Change ◽  
Boreal Summer ◽  
Northeast Monsoon ◽  
Adaptation Measures ◽  
Mitigation And Adaptation ◽  
Temperature And Precipitation ◽  
Projected Changes

Abstract Five mainland SEA countries (Cambodia, Laos, Myanmar, Vietnam, and Thailand) are threatened by climate change. Here, the latest 18 Coupled Model Intercomparison Project Phase 6 (CMIP6) is employed to examine future climate change in this region under two SSP-RCP (shared socioeconomic pathway-representative concentration pathway) scenarios (SSP2-4.5 and SSP5-8.5). The bias-corrected multi-model ensemble (MME) projects a warming (wetting) over Cambodia, Laos, Myanmar, Vietnam, and Thailand by 1.88–3.89, 2.04–4.22, 1.88–4.09, 2.03–4.25, and 1.90–3.96 °C (8.76–20.47, 12.69–21.10, 9.54–21.10, 13.47–22.12, and 7.03–15.17%) in the 21st century with larger values found under SSP5-8.5 than SSP2-4.5. The MME model displays approximately triple the current rainfall during the boreal summer. Overall, there are robust increases in rainfall during the Southwest Monsoon (3.41–3.44, 8.44–9.53, and 10.89–17.59%) and the Northeast Monsoon (−2.58 to 0.78, −0.43 to 2.81, and 2.32 to 5.45%). The effectiveness of anticipated climate change mitigation and adaptation strategies under SSP2-4.5 results in slowing down the warming trends and decreasing precipitation trends after 2050. All these findings imply that member countries of mainland SEA need to prepare for appropriate adaptation measures in response to the changing climate.

scholarly journals Bycatch composition of cutlassfish trawlers during fishing season in Bushehr and Hormozgan, Persian Gulf, Iran

2018 ◽  
Vol 19 (6) ◽  
pp. 2275-2282
Author(s):  
AHMAD FOULADI SABET ◽  
SEYED YOUSEF PAIGHAMBARI ◽  
MOJTABA POULADI ◽  
HADI RAEISI ◽  
REZA ABBASPOUR NADERI
Keyword(s):  
Data Collection ◽  
Persian Gulf ◽  
Mesh Size ◽  
Similarity Analysis ◽  
Fishing Season ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
Catch Composition

Fouladi Sabet A, Paighambari SY, Pouladi M, Raeisi H, Abbaspour Naderi R. 2018. Bycatch composition of cutlassfish trawlers during fishing season in Bushehr and Hormozgan, Persian Gulf, Iran. Biodiversitas 19: 2275-2282. This investigation was conducted to determine the bycatch composition of cutlassfish (Trichiurus lepturus) trawlers in Bushehr and Hormozgan waters during fishing season 2013. Data collection was carried out in the summer for Bushehr and in the autumn for Hormozgan province for one month. All trawler vessels were equipped with a 36 m head rope and 75 mm stretched mesh size in the codend and 90 to 200 mm stretched mesh size in the panel. 47 species included 35 species of teleosts, 9 species of elasmobranches and 3 species of invertebrates were identified in Bushehr. Also, 48 species included 38 species of teleosts, 7 species of elasmobranches and 3 species of invertebrates were identified in Hormozgan. The weight and numerical averages of bycatch species were 25.41 (kg h-1) and 205.9 (n h-1) in Bushehr, and 92.58 (kg h-1) and 440.4 (n h-1) in Hormozagan. I. megaloptera, S. tumbil, N. japonicus, D. acuta, C. sexfasciatus, L. equulus in Bushehr and P. sextarius, I. megalopteran, M. cinereus, P. macrophthalmus, N. japonicus and S. tumbil in Hormozgan had highest catch weight. Based on the weight and number, PCA and nMDS methods were indicative of two different assemblages in hunting places. Furthermore, ANOSIM similarity analysis confirmed the results of PCA and nMDS and showed a significant difference in the catch composition of two fishing zones.

scholarly journals Influence of the ENSO and Monsoonal Season on Long-Term Wind Energy Potential in Malaysia

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2965 ◽  
Author(s):  
Aliashim Albani ◽  
Mohd Ibrahim ◽  
Kim Yong
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
El Nino ◽  
Southwest Monsoon ◽  
Capacity Factor ◽  
Wind Data ◽  
Northeast Monsoon ◽  
Energy Potential ◽  
Wind Energy Potential

This paper assesses the long-term wind energy potential at three selected sites, namely Mersing and Kijal on the east coast of peninsular Malaysia and Kudat in Sabah. The influence of the El Niño-Southern Oscillation on reanalysis and meteorological wind data was assessed using the dimensionless median absolute deviation and wavelet coherency analysis. It was found that the wind strength increases during La Niña events and decreases during El Niño events. Linear sectoral regression was used to predict the long-term wind speed based on the 35 years of extended Climate Forecast System Reanalysis data and 10 years of meteorological wind data. The long-term monthly energy production was computed based on the 1.5 MW Goldwind wind turbine power curve. The measured wind data were extrapolated to the selected wind turbine default hub height (70 m.a.s.l) by using the site-specific power law indexed. The results showed that the capacity factor is higher during the Northeast monsoon (21.32%) compared to the Southwest monsoon season (3.71%) in Mersing. Moreover, the capacity factor in Kijal is also higher during the Northeast monsoon (10.66%) than during the Southwest monsoon (5.19%). However, in Kudat the capacity factor during the Southwest monsoon (36.42%) is higher compared to the Northeast monsoon (24.61%). This is due to the tail-effect of tropical storms that occur during this season in the South China Sea and Pacific Ocean.

scholarly journals Low-Frequency Currents from Deep Moorings in the Southern Bay of Bengal

2016 ◽  
Vol 46 (10) ◽  
pp. 3209-3238 ◽  
Author(s):  
H. W. Wijesekera ◽  
W. J. Teague ◽  
D. W. Wang ◽  
E. Jarosz ◽  
T. G. Jensen ◽  
...  
Keyword(s):  
Bay Of Bengal ◽  
Low Frequency ◽  
Southwest Monsoon ◽  
Naval Research ◽  
Northeast Monsoon ◽  
Intraseasonal Oscillations ◽  
The Indian Ocean ◽  
Inertial Currents ◽  
Large Eddies ◽  
Measurement Period

AbstractHigh-resolution currents and hydrographic fields were measured at six deep-water moorings in the southern Bay of Bengal (BoB) by the Naval Research Laboratory as part of an international effort focused on the dynamics of the Indian Ocean. Currents, temperature, and salinity were sampled over the upper 500 m for 20 months between December 2013 and August 2015. One of the major goals is to understand the space–time scales of the currents and physical processes that contribute to the exchange of water between the BoB and the Arabian Sea. The observations captured Southwest and Northeast Monsoon Currents, seasonally varying large eddies including a cyclonic eddy, the Sri Lanka dome (SLD), and an anticyclonic eddy southeast of the SLD. The observations further showed intraseasonal oscillations with periods of 30–70 days, near-inertial currents, and tides. Monthly averaged velocities commonly exceeded 50 cm s−1 near the surface, and extreme velocities exceeded 150 cm s−1 during the southwest monsoon. Tides were small and dominated by the M2 component with velocities of about 3 cm s−1. The average transport into the BoB over the measurement period was 2 Sv (1 Sv ≡ 106 m3 s−1) but likely exceeded 15 Sv during summer of 2014. This study suggests the water exchange away from coastal boundaries, in the interior of the BoB, may be largely influenced by the location and strength of the two eddies that modify the path of the Southwest Monsoon Current. In addition, there is a pathway below 200 m for transport of water into the BoB throughout the year.

scholarly journals Spatial Interpolation of Historical Seasonal Rainfall Indices over Peninsular Malaysia

2018 ◽  
Vol 34 ◽  
pp. 02048
Author(s):  
Zulkarnain Hassan ◽  
Ahmad Haidir ◽  
Farah Naemah Mohd Saad ◽  
Afizah Ayob ◽  
Mustaqqim Abdul Rahim ◽  
...  
Keyword(s):  
Spatial Interpolation ◽  
Rainfall Intensity ◽  
Southwest Monsoon ◽  
Peninsular Malaysia ◽  
Seasonal Rainfall ◽  
Seasonal Patterns ◽  
Northeast Monsoon ◽  
Rainfall Characteristics ◽  
Distance Weighted ◽  
Inverse Distance

The inconsistency in inter-seasonal rainfall due to climate change will cause a different pattern in the rainfall characteristics and distribution. Peninsular Malaysia is not an exception for this inconsistency, in which it is resulting extreme events such as flood and water scarcity. This study evaluates the seasonal patterns in rainfall indices such as total amount of rainfall, the frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity in Peninsular Malaysia. 40 years (1975-2015) data records have been interpolated using Inverse Distance Weighted method. The results show that the formation of rainfall characteristics are significance during the Northeast monsoon (NEM), as compared to Southwest monsoon (SWM). Also, there is a high rainfall intensity and frequency related to extreme over eastern coasts of Peninsula during the NEM season.

Soil moisture effects on cellulose decomposition in a Mediterranean ecosystem of Attica, Greece

2009 ◽  
Vol 55 (1) ◽  
pp. 63-76 ◽  
Author(s):  
Effimia Sotiriou ◽  
Margarita Arianoutsou
Keyword(s):  
Soil Moisture ◽  
Mass Loss ◽  
Eastern Mediterranean ◽  
Irrigation Treatment ◽  
Mesh Size ◽  
Mediterranean Ecosystem ◽  
Limiting Factor ◽  
Monthly Basis ◽  
Cellulose Decomposition ◽  
Significant Difference

Water is the most critical limiting factor for decomposition processes in Mediterranean climate ecosystems. The aim of this study was to investigate the effects of increased soil moisture levels upon cellulose mass loss in an eastern Mediterranean ecosystem. We used a split plot experimental design to evaluate the effect of seasonality on the decomposition process by manipulating water availability in situ during different seasons. Nylon litterbags of mesh size 20 μm and 1 mm were filled with cellulose filter paper and placed on the plots during each season. The treatment consisted of a systematic uniform watering of the plots with 7 L/m2/week. Litterbags were randomly removed from each plot on a monthly basis. Cellulose mass loss showed differences between treatment and control plots and between seasons but was significant only in the spring. Cellulose mass loss was significantly affected by irrigation treatment, season, and their interaction, while moisture seemed to be affected only by season. There was no significant difference in cellulose mass loss due to different mesh sizes.

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