Vertical distribution and population structure of Calanus finmarchicus at station India (59°N, 19°W) during the passage of the great salinity anomaly, 1971–1975

2000 ◽  
Vol 47 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Xabier Irigoien
Keyword(s):  
Population Structure ◽  
Vertical Distribution ◽  
Calanus Finmarchicus ◽  
Salinity Anomaly ◽  
Great Salinity Anomaly

Impact of Great Salinity Anomalies on the Low-Frequency Variability of the North Atlantic Climate

2006 ◽  
Vol 19 (3) ◽  
pp. 470-482 ◽  
Author(s):  
Rong Zhang ◽  
Geoffrey K. Vallis
Keyword(s):  
Surface Temperature ◽  
North Atlantic ◽  
Temperature Anomaly ◽  
Low Frequency ◽  
Sea Surface ◽  
The North ◽  
Sea Surface Temperature Anomaly ◽  
Salinity Anomaly ◽  
Great Salinity Anomaly ◽  
The North Atlantic

Abstract In this paper, it is shown that coherent large-scale low-frequency variabilities in the North Atlantic Ocean—that is, the variations of thermohaline circulation, deep western boundary current, northern recirculation gyre, and Gulf Stream path—are associated with high-latitude oceanic Great Salinity Anomaly events. In particular, a dipolar sea surface temperature anomaly (warming off the U.S. east coast and cooling south of Greenland) can be triggered by the Great Salinity Anomaly events several years in advance, thus providing a degree of long-term predictability to the system. Diagnosed phase relationships among an observed proxy for Great Salinity Anomaly events, the Labrador Sea sea surface temperature anomaly, and the North Atlantic Oscillation are also discussed.

Using a first-order autonomous dynamical system to evaluate residence time of the Greenland freshwater anomaly in the Subpolar Gyre

2020 ◽  
Author(s):  
Dmitry Dukhovskoy
Keyword(s):  
Steady State ◽  
Residence Time ◽  
North Atlantic ◽  
Thermohaline Circulation ◽  
Discharge Rate ◽  
Subpolar Gyre ◽  
The North ◽  
Salinity Anomaly ◽  
Great Salinity Anomaly ◽  
Autonomous Dynamical System

<p>Increasing Greenland discharge has contributed more than 5000 km<sup>3</sup> of surplus fresh water to the Subpolar North Atlantic since the early 1990s. The volume of this freshwater anomaly is projected to cause freshening in the North Atlantic leading to changes in the intensity of deep convection and thermohaline circulation in the subpolar North Atlantic. This is roughly half of the freshwater volume of the Great Salinity Anomaly of the 1970s that caused notable freshening in the Subpolar North Atlantic. In analogy with the Great Salinity Anomaly, it has been proposed that, over the years, this additional Greenland freshwater discharge might have a great impact on convection driving thermohaline circulation in the North Atlantic with consequent impact on climate. Previous numerical studies demonstrate that roughly half of this Greenland freshwater anomaly accumulates in the Subpolar Gyre. However, time scales over which the Greenland freshwater anomaly can accumulate in the subpolar basins is not known. This study estimates the residence time of the Greenland freshwater anomaly in the Subpolar Gyre by approximating the process of the anomaly accumulation in the study domain with a first order autonomous dynamical system forced by the Greenland freshwater anomaly discharge. General solutions are obtained for two types of the forcing function. First, the Greenland freshwater anomaly discharge is a constant function imposed as a step function. Second, the surplus discharge is a linearly increasing function. The solutions are deduced by utilizing results from the numerical experiments that tracked spreading of the Greenland fresh water with a passive tracer. The residence time of the freshwater anomaly is estimated to be about 10–15 years. The main differences in the solutions is that under the linearly increasing discharge rate, the volume of the accumulated Greenland freshwater anomaly in the Subpolar Gyre does not reach a steady state. By contrast, solution for the constant discharge rate reaches a steady state quickly asymptoting the new steady state value for time exceeding the residence time. Estimated residence time is compared with the numerical experiments and observations.</p>

scholarly journals The Vertical Distribution of Marine Macroplankton. XII. Some Observations on the Vertical Distribution of Calanus finmarchicus in Relation to Light Intensity.

1934 ◽  
Vol 19 (2) ◽  
pp. 569-584 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Light Intensity ◽  
Vertical Distribution ◽  
Calanus Finmarchicus ◽  
Upper Limit ◽  
Electric Measurement ◽  
The Vertical Distribution

1. Observations are given on the vertical distribution of adult Calanus finmarchicus in the daytime off Plymouth in July and August, 1931, as a result of collections made simultaneously with the photo-electric measurement of submarine illumination.2. A series of nets, usually six, was towed simultaneously in such a manner that the depth of each net was known approximately.3. The female Calanus in July preferred higher intensities of light than did the females in August; this change was coincident with a change in the Calanus population as shown by size measurements. A similar change in distribution and in population was shown by the males.4. The females in July were living in intensities of 20,000 m.c. and more; but those in August were avoiding such high intensities. The males in July avoided intensities of 40,000 m.c. and over, while in August their upper limit was about 10,000 m.c.

scholarly journals The Vertical Distribution of Marine Macroplankton IV. The Apparent Importance of Light Intensity as a Controlling Factor in the Behaviour of Certain Species in the Plymouth Area.

1926 ◽  
Vol 14 (2) ◽  
pp. 415-440 ◽  
Author(s):  
F. S. Russell
Keyword(s):  
Light Intensity ◽  
Vertical Distribution ◽  
Laboratory Experiments ◽  
External Factor ◽  
Controlling Factor ◽  
Calanus Finmarchicus ◽  
Different Depths ◽  
The Vertical Distribution

Results of collections with the ring-trawl to obtain evidence on the vertical distribution of plankton animals in daylight at different times of the year and at night are given.The vertical distribution of Calanus finmarchicus and Cosmelira pilosella is discussed in relation to the distribution of light intensity in the sea.Results show that light intensity is apparently the external factor of greatest importance in determining the vertical distribution of these plankton animals in this region.Many more observations at sea correlated with simultaneous records of light intensity at different depths are required, together with laboratory experiments on the effects of various factors on the behaviour of plankton animals kept under different conditions of light intensity.

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