Data Oceanografi

8/9/2019 Data Oceanografi

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Oceanography around study area

1. Hidro Oceanography

South Halmahera Sea waters are coupled to the Pacific Ocean in the north, Seram Sea and

Banda Sea in the south. The intensive oceanographic research programs through

ARL!"O program #ArusLintas ndonesia$ or T% program #ndonesian Through %low

program$ or !STA!T #nternational !usantara Stratification and Transport program$

showed that a large volume of water mass #a&out '.( Sv is e)uivalent to '.( * '+ m -sec$

has &een passing through these waters. Schematicall/ the Arlindo flow is depicted in %igure

(.

The presence of the moving mass of water throughout the /ear from the Pacific Ocean to

the ndian Ocean which is part of the current world circulation or 0reat 1onve/or Belt. This

phenomenon led to the high change of mass of water #flushing rate$ in eastern ndonesia

waters, including the mass of water in the waters around the island of O&i which is part of

the South Halmahera Archipelago.

%igure '. Halmahera Sea water is one of the shortcuts of ndonesian Traffic %low #T%$ thatmoves from the Pacific Ocean to the ndian Ocean



2. Bathymetry

n general, the depths of the ocean in South Halmahera waters can &e seen in %igure &elow.

The straits which separate one island with another island have ver/ deep waters. A depth of

'+++ m can &e found not far from the &eaches of the small islands that constitute the South

Halmahera. South Halmahera waters is flan2ed &/ astrait in &oth the left and right, has

&een e*plained a&ove, that is apath of the ARL!"O.

%igure 3. The Bath/metr/ of the waters around South Halmahera Province



4hen viewed in more detail, the depth condition of the sea around the small islands of

South Halmahera region can provide interesting insight, especiall/ in the areas protected

from large waves and have high flushing rate. n such straits can &e developed marine

culture activities such as seaweed, pearl o/sters and various 2inds of fish farming that have

important economic value.

%igure - shows the depth of the sea of the west coast of the island of O&i 5a6or. The west

coast of O&i 5a6or, &/ the presence of small islands,is relativel/ protected from strong winds

and &ig waves.

%igure 7 shows the Line8' is the ntersection sperpendicular to the shoreline, and Line83

drawn from the shoreline to the middle of the Ocean. t can &e o&served from line8' that the

depth of the sea -.'( 9m from the Shore Line is up to '-m, where as line83 shows that the

depth of the sea -.'( 9m from the Shore line is up to ':m.

%igure -. Bath/metr/ of waters around O&i 5a/or sland

%igure 7. The depth of the Sea -.'( 9m from the Shore Line



llfbDlUbn3111a4ltbnJltkm(lHim.Tlfbn(.1413. Sea

Water Temperature

0enerall/, sea surface water temperature in ndonesian waters varies with the season, also

including sea surface temperature in the waters of South Halmahera. %igure ' shows the

differences in the distri&ution of sea surface water temperature &etween south eastern

season and north eastern season. n the south eastern season the surface water

temperatures around South Halmahera waters ranged &etween 3:83;⁰1, this value is lower

than with the value of sea surface temperature during north eastern season which higher

than -+⁰1. These lower temperature phenomenon is caused &/ upwelling phenomenon

appeared in the waters of the Banda Sea during South eastern season, where during which

up flow of the low8temperature sea water mass from the &ottom la/er occurs and is replaced

&/ a higher densit/ of water mass originating from Pacific Ocean. n the north eastern

season this phenomenon does not occur, even hot temperature water masses that is piled

on the western side of the Pacific ocean tends to have stronger influence on raising

temperature in the Halmahera Sea waters.

%igure (. Sea Surface 4ater Temperature



The distri&ution of Sea Surface Temperature #SST < Sea Surface Temperature$ during

South eastern monsoon #=une to August$ and during !orth eastern monsoon #"ecem&er to

%e&ruar/$.

The results of sea surface temperature measurements made &/ the P3O8LP #3++($ in the

waters surrounding South Halmahera get the results that sea surface temperature ranged

from 3>.>3?183:.;?1. The sea water temperature of surface la/er up to a depth of (+ mis

warmer than the la/er &elow it.

4. Sea Water Salinity

Because the water of the South Halmahera Sea ndonesia is part of the general influence of

season still pla/ a role. The season significantl/ influence can &e seen from the distri&ution

of average salinit/ &etween %e&ruar/ as the pea2 season in the east #west season if the

=ava Sea$ and south eastern season. The salinit/ in the waters around South Halmahera in

%e&ruar/ #-7.+$ is lower than in August #-7.7$. The high salinit/ is not independent of the

position of the South Halmahera waters opposite the Pacific Ocean. Salinit/ in !orth

5alu2u waters include waters of the South Halmahera show a high enough value. The

results of temperature measurements made &/ the P3O 8 LP #3++($ showed the value of

-7 per mil salinit/ reached. At deeper depths, salinities value higher than the la/ers a&ove

it.

5. Tidal Wave

The phenomenon of rise and fall of sea level caused &/ periodic gravit/ of the heavenl/

&odies, especiall/ the moon and sun on the sea level on @arth raises tides. 4aters of the

&a/ are open to the Pacific Ocean lead to the phenomenon of tidal waters in South



Halmahera is a tidal wave propagation that occurs in the Pacific. 0eographical distri&ution of

the t/pes of tidal waters is the t/pe of tidal mi*8leaning dou&le tide #tide prevailing mi*ed

semidiurnal$, meaning that in one da/ happened twice ups and downs twice &ut sea levels

from tide does not same. The same condition is also derived from the results predicted &/

counting !um&ers %ormahl #%$ of the four main tidal components #9', O', 53 and S3$, its

% value is +.7.

6. Sea Water Surace !urrent

The pattern of surface currents around the island of Halmahera is also influenced &/ season

s/stem that occurred in the area. =une to August surface current end to move in a cloc2

wise direction, starting mass of water entering through the South Halmahera east and then

turn north after circling the island at speeds up to>( cmsec. n "ecem&er currents appear to

move opposite to =une of August with a speed of 3( cmsec. n %e&ruar/ of the current

&egins to &e seen moving north.

". Surace Wave

Based on the st/le of generating waves in the ocean an occur due to wind #wea2, medium

and strong$, tectonic processes #tsunami$, planetar/8scale waves #wave Ross &/ and 9elvin$

and due to the tidal waves #wave length$. "escription of this time onl/ discussed the waves

generated &/ the wind #4ind84aves$. Besides the fetch length, wind #speed and duration$ is

the main factor generating surface waves. Based on the wind data recorded in along time

scale almost '+ /ears, &etween seasons two seasons mentioned a&ove turns out to have a

dominant wind direction is different. This means that the direction of the waves that occur in

the waters around Halmahera also follow the direction of the wind. The following data is

presented in the form of wind roses wind #wind rose$ from averaging over the last '+ /ears.

n general, large waves that occur in the waters around South Halmahera seen in the

months of =une to August with an average altitude ranging &etween '.83.+ m, where as in

the other months the average was onl/ +.: m.

8.Beach !ondition

n general it can &e said that the north west coast of the island of O&i has a high diversit/.

The &each consists of non8mangrove vegetation, which consists of coastal mangroves, fine

su&strate &each with the composition of the dominant white sand &each and found too

rough ranging from gravel to roc2/.



#. Wind $irection

n the month of =anuar/ to April and !ovem&e rto "ecem&er winds moving to the !orth at

speeds ranging from 78> 2nots. n the month of 5a/ to Octo&er the windis moving to the

south at its fastest speed in Septem&er of > '+ 2nots. @ast wind directionis more varied

than the other seasons. "ifferent speeds of 4inds from the !orth west direction are

encountered in the transitional season8' #5arch 8 5a/$ and west monsoon #=une to August$,

while in season of transition83 #Septem&er8!ovem&er$ the wind direction moving toward

Southeast.

South Halmahera region has two seasons #western monsoon and eastern monsoon$.

4estern monsoon is generall/ characteried &/ high sea waves, while the @astern monsoon

is mar2ed &/ wea2 ocean waves. 4estern monsoon is usuall/ followed &/ a rain/ season

#"ecem&er 8 5arch$. At the pea2 of the west season the residents in the O&i sland are

una&le to sail due to &ad weather. @ast monsoon #dr/ season$ is starting from 5a/ to

Septem&er.

n general, almost the entire area of South Halmahera receives great wind e*posure #wave

generation$ during @astern monsoon, e*ceptin the waters along the west coast of

%igure . 4ind "irection



Halmahera #4est 0ane$. "uring 4estern monsoon, generall/, in the northern part ofSouth

Halmahera and some portion of southern areas #0uraici slands$ receive greater wind

e*posure than other regions. n the Transitional seasons ' and 3, the west coast of South

Halmahera region and most of the west coast of the island of O&i that is facing to north

west, receive great wind #wave$ evenis smaller.

The climate conditions in South Halmahera region is mostl/ influenced &/ the wind pressure

fluctuation coming from Seram Sea and 5olucca Sea.

There are two wind seasons occur in O&i island, 4est wind season and @ast wind season,

so that there are two transition periods interlude of &oth wind seasons.

The west wind season generall/ ta2es place in month of "ecem&er until 5arch, and April is

a transition period that is usuall/ a dr/ season, while the south wind season generall/ lasts

for si* months starting from 5a/ to Octo&er, and !ovem&er is the transition period that is

usuall/ a rain/ season.

The average wind speed during the transition periods of April and !ovem&er is of '+.3

2mhour with the greatest speed of '7.- 2mhour, while the average rainfall is of -++8(++

mm/ear with the num&er of :+8'(+ rain/ da/s.

South Halmahera "istrict is situated &etween ++ -+ C 8 3+ ++ C !orth latitude and that is ver/

close to the latitude of the e)uator. t has a tropical climate with average temperatures

ranging &etween 3>⁰18-+?1.

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Data Oceanografi