Seasonal variations in the Indian Ocean along 110°E. III. Chlorophylls a and c

1969 ◽  
Vol 20 (1) ◽  
pp. 55 ◽  
Author(s):  
GF Humphrey ◽  
JD Kerr
Keyword(s):  
Regression Analysis ◽  
Indian Ocean ◽  
Water Column ◽  
Chlorophyll A ◽  
Seasonal Variations ◽  
The Indian Ocean ◽  
The Mean

The mean concentrations for all samples analysed were 0.17 �g/l for chlorophyll a and 0.22 �g/I. for chlorophyll c; there were 27 mg/m² of a and 35 mg/m² of c in the water column to 150 m. June-August gave the highest values. The model depth at which concentrations were greatest was 75 m. Diagrams of regression surfaces fitted to the results are given. Regression analysis showed that depth, latitude, and season affected the concentration of chlorophylls; latitude and season affected the column amount of chlorophylls.

Seasonal variations in the Indian Ocean along 110°E. II. Particulate carbon

1969 ◽  
Vol 20 (1) ◽  
pp. 51 ◽  
Author(s):  
BS Newell
Keyword(s):  
Indian Ocean ◽  
Seasonal Variations ◽  
Combustion Method ◽  
Particulate Material ◽  
Particulate Carbon ◽  
The Indian Ocean

Particulate carbon at 0, 50, 100, 150, and 200 m was measured by a combustion method. Mineral carbon appeared to be negligible. Some particulate material escaped the Whatman GF/C filters used. The amount of suspended carbon decreased with depth at most stations from values of 20 �g/l, or more at 0 and 50 m, to 15 �g/l, at 150 m, and 10�g/l, at 150 and 200m. Higher values were found at all depths at the two southernmost stations (25-30 �g/I. at 0 and 50 m decreasing to 15 �gll. at 150 and 200 m ) and at shallow depths at the northernmost stations (20-25 �g/l. at 0 and 50m). At all stations and at all depths, least carbon occurred in March.

scholarly journals Dynamics of the seasonal variations in the Indian Ocean from TOPEX/POSEIDON sea surface height and an ocean model

1998 ◽  
Vol 25 (11) ◽  
pp. 1915-1918 ◽  
Author(s):  
Jiayan Yang ◽  
Lisan Yu ◽  
Chester J. Koblinsky ◽  
David Adamec
Keyword(s):  
Indian Ocean ◽  
Seasonal Variations ◽  
Sea Surface Height ◽  
Ocean Model ◽  
Sea Surface ◽  
The Indian Ocean

scholarly journals Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 3190-3209 ◽  
Author(s):  
Lisan Yu ◽  
Xiangze Jin ◽  
Robert A. Weller
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Seasonal Cycle ◽  
Arabian Sea ◽  
Heat Fluxes ◽  
The Other ◽  
Net Heat Flux ◽  
The Indian Ocean ◽  
The Mean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

scholarly journals COMPARISON OF INDONESIAN TUNA LONGLINE FISHING PERFORMANCE WITHIN AND OUTSIDE INDONESIA EXCLUSIVE ECONOMIC ZONE (EEZ)

2017 ◽  
Vol 23 (1) ◽  
pp. 1
Author(s):  
Bram Setyadji ◽  
Irwan Jatmiko
Keyword(s):  
Indian Ocean ◽  
Bluefin Tuna ◽  
T Test ◽  
Exclusive Economic Zone ◽  
Southern Bluefin Tuna ◽  
The Indian Ocean ◽  
The Mean ◽  
Economic Zone ◽  
Tuna Longline ◽  
High Seas

Indonesian tuna longline fleets have been fishing in the Exclusive Economic Zone (EEZ) and high seas of the Indian Ocean for quite some time. However, effort has never been made to separate catch from the EEZ and the high seas as it important for fisheries management. A total of 2,430 set-by-set longline fishing data had been collected by scientific observers based in the Research Institute of Tuna Fishery in Bali since August 2005 to December 2014 on which present analysis was made. The research aims to compare between trend of tuna catch of the EEZ and of the high seas of Indian Ocean. The results show that the mean hook rate of both catches of big eye tuna (BET) and southern Bluefin tuna (SBT) caught in the high seas was significantly higher than that the EEZ (two sample t-test, p<0.05), while for yellow fin tuna (YFT) it was in the opposite direction (two sample t-test, p<0.05). As for albacore (ALB), the mean hook rate value was statistically similar in both fishing grounds (two sample t-test, p>0.05).

Seasonal variations in the Indian Ocean along 110°E. IV. Primary production

1969 ◽  
Vol 20 (1) ◽  
pp. 65 ◽  
Author(s):  
HR Jitts
Keyword(s):  
Indian Ocean ◽  
Primary Production ◽  
Seasonal Variations ◽  
High Productivity ◽  
Photosynthetic Organisms ◽  
South Indian ◽  
Daily Rate ◽  
Deep Layers ◽  
Equatorial Upwelling ◽  
The Indian Ocean

Mean productivity (light saturated photosynthesis), Ps, for the meridian rose from 50 mg C/(hr m²) in August 1962 to a maximum of 62 in October, then fell to a minimum of 4 in January, whereafter it rose slowly to 25 in April-May, then sharply to 45 in late May, and remained at that level till August 1963. Mean Ps for the year was 37 mg C/(hr m²). The depth of the layer of photosynthetic organisms varied between 130 m in October and 60 m in January, with a mean of 85 m. Maximum Ps occurred at 25 m in 36% of the stations, at 0 m in 29 %, and at 50 m in 24%. In January-February the whole meridian was occupied by waters of low productivity, approximately 4 mg C/(hr m²) from the centre of the south Indian Ocean. In April-May the Ps remained uniform along the meridian but rose to 24. At other times four latitudinal intervals along the meridian, with distinctive seasonal variations of productivity characteristics, were found. From 9 to 15°S., waters with high Ps (69 mg C/(hr m²)), and sharp stratification at 50 m, caused by equatorial upwelling, occurred from May to October. From 15 to 24 and 24 to 30°S., waters with high Ps (60 mg Cl(hr m²) and (100 m) deep layers of photosynthetic organisms were found during October-November and May-July respectively. From 30 to 32�S., waters of high productivity (70 mg C/(hr m²)) and a deep layer (100 m) were found in the period July-August. The daily rate of primary production, Pa, of the whole meridian varied from 0.13 g C/(day m²) in August to 0.08 from October to early May, rising sharply in late May to 0.18 and again in early August to 0.27. The depth of the euphotic layer varied between 76 m in October and 63 m in July-August, with a mean of 68 m.

scholarly journals Strong Intraseasonal Variability of Meridional Currents near 5°N in the Eastern Indian Ocean: Characteristics and Causes

2017 ◽  
Vol 47 (5) ◽  
pp. 979-998 ◽  
Author(s):  
Gengxin Chen ◽  
Weiqing Han ◽  
Yuanlong Li ◽  
Michael J. McPhaden ◽  
Ju Chen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Rossby Waves ◽  
Intraseasonal Variability ◽  
Upper Ocean ◽  
Mean Flow ◽  
Eastern Boundary ◽  
Typical Period ◽  
The Indian Ocean ◽  
The Mean

AbstractThis paper reports on strong, intraseasonal, upper-ocean meridional currents observed in the Indian Ocean between the Bay of Bengal (BOB) and the equator and elucidates the underlying physical processes responsible for them. In situ measurements from a subsurface mooring at 5°N, 90.5°E reveal strong intraseasonal variability of the meridional current with an amplitude of ~0.4 m s−1 and a typical period of 30–50 days in the upper 150 m, which by far exceeds the magnitudes of the mean flow and seasonal cycle. Such prominent intraseasonal variability is, however, not seen in zonal current at the same location. Further analysis suggests that the observed intraseasonal flows are closely associated with westward-propagating eddylike sea surface height anomalies (SSHAs) along 5°N. The eddylike SSHAs are largely manifestations of symmetric Rossby waves, which result primarily from intraseasonal wind stress forcing in the equatorial waveguide and reflection of the equatorial Kelvin waves at the eastern boundary. Since the wave signals are generally symmetric about the equator, similar variability is also seen at 5°S but with weaker intensity because of the inclined coastline at the eastern boundary. The Rossby waves propagate westward, causing pronounced intraseasonal SSHA and meridional current in the upper ocean across the entire southern BOB between 84° and 94°E. They greatly weaken in the western Indian Basin, but zonal currents near the equator remain relatively strong.

The concentration of chlorophylls a and c in the south-east Indian Ocean

1966 ◽  
Vol 17 (2) ◽  
pp. 135 ◽  
Author(s):  
GF Humphrey
Keyword(s):  
Indian Ocean ◽  
Water Column ◽  
Chlorophyll A ◽  
The South ◽  
Average Amount ◽  
East Indian ◽  
Similar Work ◽  
East Indian Ocean

Samples were collected in 1959-62, usually at 0, 25, 50, 75, 100, and 150 m, in the region between 90 and 140� E., and 10� N. and 50�S. At 0 m (and 150 m) the regional average for chlorophyll a was 0.08 (and 0.09) �p/l in summer and 0.12 (and 0.09) �p/l in winter; for chlorophyll c the values were 0.17 (and 0.21) �p/l in summer and 0.21 (and 0.21) �p/l in winter. Most samples had chlorophyll c/a ratios between 1 and 2. The average amount of chlorophyll a in the water column to 150 m was 15 mg/m² in summer and 23 in winter; for chlorophyll c the values were 29 mg/m² in both summer and winter. At most stations the maximum amounts of chlorophyll were at 75 m, often near density and temperature discontinuities. At 75 m the regional average for chlorophyll a was 0.14 �pll in summer and 0.19 in winter; for chlorophyll c the values were 0.35 and 0.24. The results of the present and similar work show that the amounts of the chlorophylls in the water column under 1 m² are similar for all oceans.

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