scholarly journals Preliminary Findings on Distribution of Bali Sardinella (Sardinella lemuru) in Relation to Oceanographic Conditions during Southeast Monsoon in Bali Strait Using Remotely Sensed Data

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Achmad Fachruddin Syah ◽  
Nurul Setyowati ◽  
Eko Susilo

Bali sardinella (Sardinella lemuru) is the main fishing catches in Bali Strait. The distribution of S. lemuru and its preferred oceanographic condition were investigated from remotely sensed data. The objectives of this study were to elucidate the distribution of S. lemuru and the preferred oceanographic condition of S. lemuru in Bali Strait using remotely sensed data. Sea surface temperature (SST) and sea surface chlorophyll-a (chl-a) were downloaded from ocean colour website meanwhile the fishing location generated from daily Visible Infrared Imaging Radiometer Suite (VIIRS) boat detection (VDB), downloaded from NOAA website. The results showed that at the beginning of southeast monsoon (April), most of the fishing location appeared in the north part of Bali Strait, and moved to south part of Bali Strait at the end of the southeast monsoon (September). The results also revealed that most of fishing location of S. lemuru located in SST value of 26 – 30 °C and chl-a value of 0.3 – 0.8 mg/m3. Integration VDB data and oceanographic condition generated from remotely sensed data could form the basis for fisheries management and information system, such as S. lemuru in Bali Strait, in the future.

2005 ◽  
Vol 62 (3) ◽  
pp. 319-327 ◽  
Author(s):  
Jeffrey J. Polovina ◽  
Evan A. Howell

Abstract Satellite remotely sensed oceanographic data provide reliable global ocean coverage of sea surface temperature, sea surface height, surface winds, and ocean colour, with relatively high spatial and temporal resolution. We illustrate approaches to use these data to construct indicators that describe aspects of ecosystem dynamics in the North Pacific. Specifically, altimetry data are used to construct regional indicators of the ocean vertical structure, ocean colour data to describe the temporal chlorophyll dynamics of the coastal zone, ocean colour, sea surface temperature, and altimetry data to develop indices of biologically important ocean features, and finally altimetry data to drive a larval transport model and develop an index of larval retention. Recent changes in the North Pacific based on these indices are discussed.


2020 ◽  
Vol 5 (1) ◽  
pp. 62-70
Author(s):  
Achmad Fachruddin-Syah ◽  
Jonson Lumban Gaol ◽  
Mukti Zainuddin ◽  
Nadela Rista Apriliya ◽  
Dessy Berlianty ◽  
...  

Bigeye tuna (Thunnus obesus) is one of the commercially important pelagic species that caught mostly in the eastern Indian Ocean. This species prefers to stay close, and is usually below the thermocline layer. Remotely sensed data was used to determine the characteristics of Bigeye tuna fishing areas at a depth of 155 meter. Fishing vessels for Bigeye tuna were obtained from vessel monitoring systems (VMS) from January through December, 2015-2016. Daily data on sub-surface temperature (SST), sub-surface chlorophyll-a concentration (SSC), and sub-surface salinity (SSS) were obtained from the INDESO Project website. All oceanographic parameter data were selected at a depth of 155 m. The position of Bigeye tuna and oceanographic data were then grouped into 2 group monsoon, southeast monsoon (April – September) and northwest monsoon (October – March). The results showed that, during the southeast and northwest monsoon, Bigeye tuna mostly found in SSC of 0.03 – 0.05 mg/m3, SST of 16° - 18°C and salinity of 34 psu. These results showed that at depth of 155 m, Bigeye Tuna prefers to stay in small chl-a (0.03 – 0.04 mg/m3), low SST (16° - 18°C) and salinity of 34 psu. These information were essential and could be used to support fisheries management decisions especially for Bigeye Tuna in the eastern Indian Ocean.


2020 ◽  
Vol 12 (24) ◽  
pp. 4139
Author(s):  
Ruirui Wang ◽  
Wei Shi ◽  
Pinliang Dong

The nighttime light (NTL) on the surface of Earth is an important indicator for the human transformation of the world. NTL remotely sensed data have been widely used in urban development, population estimation, economic activity, resource development and other fields. With the increasing use of artificial lighting technology in agriculture, it has become possible to use NTL remote sensing data for monitoring agricultural activities. In this study, National Polar Partnership (NPP)-Visible Infrared Imaging Radiometer Suite (VIIRS) NTL remote sensing data were used to observe the seasonal variation of artificial lighting in dragon fruit cropland in Binh Thuan Province, Vietnam. Compared with the statistics of planted area, area having products and production of dragon fruit by district in the Statistical Yearbook of Binh Thuan Province 2018, values of the mean and standard deviation of NTL brightness have significant positive correlations with the statistical data. The results suggest that the NTL remotely sensed data could be used to reveal some agricultural productive activities such as dragon fruits production accurately by monitoring the seasonal artificial lighting. This research demonstrates the application potential of NTL remotely sensed data in agriculture.


2004 ◽  
Vol 61 (5) ◽  
pp. 804-816 ◽  
Author(s):  
S Belviso ◽  
C Moulin ◽  
L Bopp ◽  
J Stefels

A method is developed to estimate sea-surface particulate dimethylsulfoniopropionate (DMSPp) and dimethylsulfide (DMS) concentrations from sea-surface concentrations of chlorophyll a (Chl a). When compared with previous studies, the 1° × 1° global climatology of oceanic DMS concentrations computed from 4 years (1998–2001) of Chl a measurements derived from SeaWiFS (satellite-based, sea-viewing wide field of view sensor) exhibits lower seasonal variability in the southern hemisphere than in the northern hemisphere. A first evaluation of the method shows that it reasonably well represents DMSPp and DMS in the North Atlantic subtropical gyre, in large blooms of mixed populations of diatoms and Phaeocystis spp., and in massive blooms of Phaeocystis spp. but fails for large, almost pure blooms of diatoms. DMSPp and DMS concentrations derived from SeaWiFS were also compared with spatially and temporally coincident in situ measurements acquired independently in the Atlantic between 39°N and 45°N and in subtropical and subantarctic Indian Ocean surface waters. Moderate spring and summer phytoplankton blooms there exhibited similar trends in DMSPp and DMS levels vs. moderate blooms of mixed populations of prymnesiophytes and dinoflagellates investigated by others. Measured DMS largely exceeded simulated DMS concentrations, whereas measured and simulated DMSPp levels were in close agreement. DMS accumulation is tentatively attributed to dinoflagellate DMSP lyase activity.


2010 ◽  
Vol 10 (11) ◽  
pp. 27283-27320
Author(s):  
M. S. Johnson ◽  
N. Meskhidze ◽  
V. P. Kiliyanpilakkil ◽  
S. Gassó

Abstract. The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of Northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system) elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of Northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem), implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble iron, while a dust/biota assessment tool (Boyd et al., 2010) is applied to evaluate the amount of bioavailable iron formed through the slow and sustained leaching of dust in the ocean mixed layer. The effect of iron-laden mineral dust supply on surface ocean biomass is investigated by comparing predicted surface chlorophyll-a concentration ([Chl-a]) to remotely-sensed data. As the dust transport episodes examined here represent large summertime outflows of mineral dust from South American continental sources, this study suggests that (1) atmospheric fluxes of mineral dust from Patagonia are not likely to be the major source of bioavailable iron to ocean regions characterized by high primary productivity; (2) even if Patagonian dust plumes may not cause visible algae blooms, they could still influence background [Chl-a] in the South Atlantic sector of the Southern Ocean.


Author(s):  
R. Doerffer ◽  
W. Puls ◽  
D. Pan ◽  
H.-H. Essen ◽  
K.-W. Gurgel ◽  
...  

2012 ◽  
Vol 9 (8) ◽  
pp. 10087-10120 ◽  
Author(s):  
I. Borrione ◽  
R. Schlitzer

Abstract. South Georgia phytoplankton blooms are amongst the largest of the Southern Ocean and are associated with a rich ecosystem and strong atmospheric carbon drawdown. Both aspects depend on the intensity of blooms, but also on their regularity. Here we use data from 12 yr of SeaWiFS ocean colour imagery and calculate the frequency of bloom occurrence (FBO) to re-examine spatial and temporal bloom distributions. We find that upstream of the island and outside the borders of the Georgia Basin, blooms occurred in less than 4 out of the 12 yr (FBO < 4). In contrast, FBO was mostly greater than 8 downstream of the island, i.e. to the north and northwest, and in places equal to 12, indicating that blooms occurred every year. The typical bloom area, defined as the region where blooms occurred in at least 8 out of the 12 yr, covers the entire Georgia Basin and the northern shelf of the island. The time series of surface chlorophyll-a (chl-a) concentrations averaged over the typical bloom area shows that phytoplankton blooms occurred in every year between September 1997 and September 2010, and that chl-a values followed a clear seasonal cycle, with concentration peaks around December followed in many years by a second peak during late austral summer or early autumn, suggesting a bi-modal bloom pattern. The bloom regularity we describe here is in contrast with results of Park et al. (2010) who used a significantly different study area including regions that almost never exhibit bloom conditions.


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