scholarly journals OBSERVATION OF COASTAL FRONT AND CIRCULATION IN THE NORTHEASTERN JAVA SEA, INDONESIA

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Agus S. Atmadipoera ◽  
Edi Kusmanto ◽  
Adi Purwandana ◽  
I Wayan Nurjaya
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
River Estuary ◽  
Acoustic Doppler Current Profiler ◽  
Water Source ◽  
Observation Time ◽  
Joint Research ◽  
Current Profiler ◽  
Java Sea ◽  
Coastal Front

<p><em>The structure and spatial extent of a coastal front and circulation in the shallow (&lt;55 m depth) northeastern Java Sea in Indonesia was investigated with a new dataset of high-resolution conductivity-temperature-depth (CTD) and along-track shipboard acoustic Doppler current profiler (SADCP) during a DIKTI-LIPI 2010 joint research cruise on R.V. Baruna Jaya 8.  The coastal front separates fresh warm coastal water derived mainly from Barito River discharge and the saline, cool Java Sea water.  The surface fresh water plume extends approximately 760 km from the Barito River estuary to the south, and its thickness varies from the surface to 10 m and 20 m depth, depending on its proximity to the fresh water source.  The front is aligned a northeast and east direction, probably related to a meandering of strong northeastward monsoon current in the eastern part of the Java Sea during the observation time.</em></p> <p><em> </em></p> <p><strong><em>Keywords:</em></strong><em> hydrographic measurement, coastal front, Matasiri Islands, Barito River, the northwest</em><em> monsoon current</em></p>

scholarly journals OBSERVATION OF COASTAL FRONT AND CIRCULATION IN THE NORTHEASTERN JAVA SEA, INDONESIA

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Agus S. Atmadipoera ◽  
Edi Kusmanto ◽  
Adi Purwandana ◽  
I Wayan Nurjaya
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
River Estuary ◽  
Acoustic Doppler Current Profiler ◽  
Water Source ◽  
Observation Time ◽  
Joint Research ◽  
Current Profiler ◽  
Java Sea ◽  
Coastal Front

The structure and spatial extent of a coastal front and circulation in the shallow (<55 m depth) northeastern Java Sea in Indonesia was investigated with a new dataset of high-resolution conductivity-temperature-depth (CTD) and along-track shipboard acoustic Doppler current profiler (SADCP) during a DIKTI-LIPI 2010 joint research cruise on R.V. Baruna Jaya 8.  The coastal front separates fresh warm coastal water derived mainly from Barito River discharge and the saline, cool Java Sea water.  The surface fresh water plume extends approximately 760 km from the Barito River estuary to the south, and its thickness varies from the surface to 10 m and 20 m depth, depending on its proximity to the fresh water source.  The front is aligned a northeast and east direction, probably related to a meandering of strong northeastward monsoon current in the eastern part of the Java Sea during the observation time. Keywords: hydrographic measurement, coastal front, Matasiri Islands, Barito River, the northwest monsoon current

scholarly journals Sea-ice growth and water-mass modification in the Mertz Glacier polynya, East Antarctica, during winter

2001 ◽  
Vol 33 ◽  
pp. 399-406 ◽  
Author(s):  
N. L. Bindoff ◽  
G. D. Williams ◽  
I. Allison
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Fresh Water ◽  
Acoustic Doppler Current Profiler ◽  
Water Masses ◽  
Surface Velocity ◽  
Return Flow ◽  
Shelf Water ◽  
Ice Growth ◽  
Current Profiler

AbstractIn July-September 1999, an extensive oceanographic survey (87 conductivity-, temperature-and depth-measuring stations) was conducted in the Mertz Glacier polynya over the Adélie Depression off the Antarctic coast between 145° and 150° E. We identify and describe four key water masses in this polynya: highly modified circumpolar deep water (HMCDW), winter water (WW), ice-shelf water (ISW) and high-salinity shelf water (HSSW). Combining surface velocity data (from an acoustic Doppler current-profiler) with three hydrographic sections, we found the HMCDW to be flowing westward along the shelf break (0.7 Sv), the WW and HSSW flowing eastwards underneath Mertz Glacier (2.0 Sv) and that there was a westward return flow of ISW against the continent (1.2 Sv). Using a simple box model for the exchanges of heat and fresh water between the principal water masses, we find that the polynya was primarily a latent-heat polynya with 95% of the total heat flux caused by sea-ice formation. This heat flux results from a fresh-water-equivalent sea-ice growth rate of 4.9−7.7 cm d−1 and a mass exchange between HMCDW and WW of 1.45 Sv The inferred ocean heat flux is 8−14 W m−2 and compares well with other indirect estimates.

Flow and Stratification in a Bedrock Confined Estuary

2021 ◽  
Author(s):  
Amanda Wild ◽  
Eva Kwoll
Keyword(s):  
River Estuary ◽  
Acoustic Doppler Current Profiler ◽  
Limited Information ◽  
Cross Sectional ◽  
Current Profiler ◽  
Hydrodynamic Processes ◽  
Ongoing Development ◽  
Skeena River ◽  
The Impact ◽  
Temperature Depth

&lt;p&gt;This research describes the impact of the bedrock island structure on the circulation and stratification of a macrotidal, partially mixed estuary in northwestern Canada (the Skeena River Estuary). Due to ongoing development in this formerly remote region, pressures have increased within the Skeena River Estuary over the past decade. However, there is still limited understanding of the estuary's morphodynamics due to its deviation from a 'typical' estuarine morphology. Located along an emergent, fjordal coastline, the Skeena Estuary River drains into a basin confined by bedrock and interrupted by multiple, irregular bedrock islands. Observations suggest that a subaqueous delta, associated facies, and the surface plume are split between several bedrock passages with limited information on the governing hydrodynamic processes. To overcome this, Acoustic Doppler current profiler cross-sectional transects and conductivity, temperature, depth, and turbidity profiles were taken in the nearshore (under 40 m) at locations across the estuary over two different (by ~1000 m&lt;sup&gt;3&lt;/sup&gt;s&lt;sup&gt;-1&lt;/sup&gt;) river stages. Over multiple dates with various river inflows, the tidal ratio to river inflow produces varied stratification patterns at a given site. During one point in time and river stage, bedrock passages are disproportionally exposed to marine and fluvial inflows, creating spatially diverse stratification patterns across the estuary. Stratification and passage morphology interactions determine the characteristics of tidal slack transitions, with horizontal and vertical separation occurring during well-mixed conditions and stratified conditions, respectively.&lt;/p&gt;

scholarly journals Sea Water Characterization at Ujung Kulon Coastal Depth as Raw Water Source for Desalination and Potential Energy

2018 ◽  
Vol 31 ◽  
pp. 02005 ◽  
Author(s):  
Dan Mugisidi ◽  
Okatrina Heriyani
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Chemical Properties ◽  
Water Source ◽  
Sodium Sulphate ◽  
Raw Water ◽  
Energy Potential ◽  
Allowable Level ◽  
Physical And Chemical ◽  
And Chemical Properties

Fresh water is basic need for life while the source is limited. Therefore, sea water is used as fresh water through desalination process. Sea water has different physical and chemical properties ranging from the surface to the seabed. The energy potential that can be obtained from the hydrostatic pressure also changes according to the depth. As part of the research of the utilization of sea water into fresh water, the aim of this study is to know the characteristics of sea water in the depth that can be utilized as source of fresh water. The sea water samples were taken at 11km from Ujung Kulon beach with depth of 0m, 20m, 40m, 60m, 80m, and 100m under the surface. The results showed that the physical properties at every depth were below the maximum allowable drinking water except for the amount of dissolved solids. Chemical characteristics at any depth above allowable level were fluoride, hardness (CaCo3), chloride, sodium, sulphate, and (KMnO4). In addition to the properties, pressure is one of the considerations in this study to determine the depth of sea water as sources for desalination. Pressure increased by 36.11% as the depth of the sea increased.

scholarly journals Mixing and Entrainment in the Red Sea Outflow Plume. Part II: Turbulence Characteristics

2005 ◽  
Vol 35 (5) ◽  
pp. 584-600 ◽  
Author(s):  
Hartmut Peters ◽  
William E. Johns
Keyword(s):  
Red Sea ◽  
Sea Water ◽  
Acoustic Doppler Current Profiler ◽  
Bottom Layer ◽  
Small Sample ◽  
Interfacial Stress ◽  
Salt Flux ◽  
Turbulent Dissipation ◽  
Eddy Diffusivities ◽  
Current Profiler

Abstract South of the Strait of Bab el Mandeb, saline Red Sea Water flows downslope into the Gulf of Aden mainly along the narrow 130-km-long “Northern Channel” (NC) and the shorter and wider “Southern Channel” (SC). In the NC, the Red Sea plume simultaneously exhibited weak entrainment into a 35–120-m-thick, weakly stratified bottom layer while a 35–285-m-thick interfacial layer above showed signs of vigorous mixing, overturns up to 30 m thick, and extensive zones of gradient Richardson numbers below 1/4. Turbulent overturning scales, or Thorpe scales, are extracted from regular CTD profiles and equated to Ozmidov scales. On this basis, interfacial mixing is quantified in terms of estimated turbulent dissipation rates, vertical turbulent salt flux, and interfacial stress. Even though these estimates are subject to significant uncertainty, they demonstrate the intensity of mixing during strong winter outflow in terms of eddy diffusivities Kρ on the order of 10−2 m2 s−1. The large Kρ occur in strong stratification such that vertical turbulent salt fluxes are also large. Along the NC, relative maxima of Kρ correspond to maxima in the bulk Froude number. Direct short-term measurements of the Reynolds stress just above the seafloor at two locations, one in the NC and one in the SC, allow comparisons of the bottom stress τb with the interfacial turbulent stress τi. The ratio τi/τb shows large scatter in a small sample, with maximum values on the order of 1. An appendix outlines procedures of making and reducing lowered acoustic Doppler current profiler measurements optimized for observing descending plumes.

scholarly journals Direct Observations of Along-Isopycnal Upwelling and Diapycnal Velocity at a Shelfbreak Front*

2004 ◽  
Vol 34 (3) ◽  
pp. 543-565 ◽  
Author(s):  
John A. Barth ◽  
Dave Hebert ◽  
Andrew C. Dale ◽  
David S. Ullman
Keyword(s):  
Three Dimensional ◽  
Internal Tide ◽  
Acoustic Doppler Current Profiler ◽  
Density Field ◽  
Strong Mixing ◽  
Optical Fields ◽  
Direct Observations ◽  
Current Profiler ◽  
Southern Flank ◽  
Coastal Front

Abstract By mapping the three-dimensional density field while simultaneously tracking a subsurface, isopycnal float, direct observations of upwelling along a shelfbreak front were made on the southern flank of Georges Bank. The thermohaline and bio-optical fields were mapped using a towed undulating vehicle, and horizontal velocity was measured with a shipboard acoustic Doppler current profiler. A subsurface isopycnal float capable of measuring diapycnal flow past the float was acoustically tracked from the ship. The float was released near the foot of the shelfbreak front (95–100-m isobath) and moved 15 km seaward as it rose from 80 to 50 m along the sloping frontal isopycnals over a 2-day deployment. The float's average westward velocity was 0.09 m s−1, while a drifter drogued at 15 m released at the same location moved westward essentially alongfront at 0.18 m s−1. The float measured strong downward vertical velocities (in excess of 0.02 m s−1) associated with propagation of internal tidal solibores in the onbank direction from their formation near the shelf break. The float measured large upward vertical velocities (in excess of 0.001 m s−1 ≃ 100 m day−1) as the pycnocline rebounded adiabatically after the passage of the internal tide solibore. The directly measured mean along-isopycnal vertical velocity was 17.5 m day−1. Intense mixing events lasting up to 2 hours were observed in the shelfbreak front at the boundary between cold, fresh shelf water and warm, salty slope water. Diapycnal velocities of up to 3 × 10−3 m s−1 were measured, implying a diapycnal thermal diffusivity as large as 10−2 m2 s−1, indicative of strong mixing events in this coastal front.

scholarly journals Calculated Potential Bedload Versus Real Transported Sands along the Guadiana River Estuary (Spain–Portugal)

2019 ◽  
Vol 7 (11) ◽  
pp. 393
Author(s):  
Juan A. Morales ◽  
Claudio Lozano ◽  
Mouncef Sedrati
Keyword(s):  
Bottom Water ◽  
River Estuary ◽  
Acoustic Doppler Current Profiler ◽  
Bedload Transport ◽  
Cohesive Sediments ◽  
Coastal System ◽  
Deep Channel ◽  
Current Profiler ◽  
Comparison Of The Results ◽  
Guadiana Estuary

The Guadiana estuary is a coastal system located in the southwest of the Iberian Peninsula and is the natural border between Portugal and Spain. It is a rock-bounded estuary which extends along more than 40 km and is characterized by a semidiurnal mesotidal regime. This paper represents an approach to the bedload transport across two flow sections located in the fluvial and marine domains. In the fluvial profile, the most frequent bedform is the plane bed. In the marine area the bed of the deep channel is composed of well-sorted sand, while a lateral bar displays partially cohesive sediments with dominant fine sands in a matrix of clayey silts. Data were acquired during spring and neap tides. Near-bottom water velocities were registered by an acoustic Doppler current profiler (ADCP). Density and bed rugosity were determined in sediment samples. These data were employed using Bagnold’s equation (1963) to quantify the potential bedload (Qb). Further, real bedload values (Sb) were obtained by using Poliakoff traps. The comparison of the results of Qb under both ebb and flood conditions demonstrated a clear river-to-sea net transport in both sectors. The values of Sb were lower than those of Qb in every condition. The sand input across the fluvial estuary cannot supply the potential bedload in the lower domain of the channel, thereby causing a deficit that explains this lack of agreement between potential and real transport.

Aplikasi metode tahanan jenis dalam studi geologi karst Gua Seropan di Gunung Kidul, Yogyakarta

2017 ◽  
Vol 12 (2) ◽  
pp. 105-116
Author(s):  
Pulung A. Pranantya ◽  
Nurlia Sadikin
Keyword(s):  
Fresh Water ◽  
Ground Surface ◽  
Water Source ◽  
Raw Water ◽  
Limited Information ◽  
Resistivity Method ◽  
Central Java ◽  
Underground River ◽  
Initial Exploration

In terms of geology, most areas in south of the Gunungkidul District in Central Java consist of the Wonosari formation limestone. The land is generally very dry and source of raw water is also difficult to reach. Findings on the existence of underground river in caves, however, indicate the potential amount of water within the area, especially in the eastern part of the Gunungkidul District. Although limited information available, some fishermen have discovered that Seropan cave contains fresh water source. This cave is situated at 65 m below the cliff. Initial exploration, which done using a multichannel resistivity method, confirmed the availability of freshwater in the cave and underground river. The isopach of cave depth is found in ranges of 80 200 m below the ground surface. The water of Seropan cave can be utilized by implementing pipeline or by drilling at the suggested point based on the interpretation results, i.e. 110o2223.6388 EL 8o42.874 SL. [DY1][PP2][DY1]Perbaiki grammarIn terms of geology, most areas in south of Gunungkidul District in Central Java consist of the Wonosari formation limestone. The land is generally very dry and source of raw water is also difficult to reach. Findings on the exixtence of underground river in caves, however, indicate potential amount of water within the area especially in eastern part of Gunungkidul District. Although limited information available, some fishermans has discovered that Seropan cave contain fresh water source. This cave is situated at 65 m below the cliff. Initial exploration, which done using multichannel resistivity method, confirmed the availability of freshwater in the cave and underground river. The iso pach of cave depth is found in ranges of 80 200 m below the ground surface. The water of Seropan cave can be utilized by implementing pipeline or by drilling at the suggested point based on the interpretation results i.e. 110o2223.6388 EL 8o42.874 SL.[PP2]Sudah diperbaiki

Investigational Studies on Quantity of Salinity in Netravati River Estuary Sand-Coastal Karnataka

2018 ◽  
Vol 6 (6) ◽  
pp. 46
Author(s):  
Raveesha P ◽  
K. E. Prakash ◽  
B. T. Suresh Babu
Keyword(s):  
Brackish Water ◽  
Sea Water ◽  
Salt Water ◽  
Construction Material ◽  
Salt Content ◽  
River Estuary ◽  
Sand Sample ◽  
River Sand ◽  
Natural Aggregates

The salt water mixes with fresh water and forms brackish water. The brackish water contains some quantity of salt, but not equal to sea water. Salinity determines the geographic distribution of the number of marshes found in estuary. Hence salinity is a very important environmental factor in estuary system. Sand is one major natural aggregate, required in construction industry mainly for the manufacture of concrete. The availability of good river sand is reduced due to salinity. The quality of sand available from estuarine regions is adversely affected due to this reason. It is the responsibility of engineers to check the quality of sand and its strength parameters before using it for any construction purpose. Presence of salt content in natural aggregates or manufactured aggregates is the cause for corrosion in steel. In this study the amount of salinity present in estuary sand was determined. Three different methods were used to determine the salinity in different seasonal variations. The sand sample collected nearer to the sea was found to be high in salinity in all methods.  It can be concluded that care should be taken before we use estuary sand as a construction material due to the presence of salinity.

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