Response of Subantarctic microbes to new versus regenerated Fe in a cold-core eddy

2021 ◽  
Author(s):  
Marion Fourquez ◽  
Robert Strzepek ◽  
Michael J Ellwood ◽  
Christel Hassler ◽  
Damien Cabanes ◽  
...  
Keyword(s):  
Cold Core

scholarly journals Air-Sea Interactions over Eddies in the Brazil-Malvinas Confluence

2021 ◽  
Vol 13 (7) ◽  
pp. 1335
Author(s):  
Ronald Souza ◽  
Luciano Pezzi ◽  
Sebastiaan Swart ◽  
Fabrício Oliveira ◽  
Marcelo Santini
Keyword(s):  
Latent Heat ◽  
Large Scale ◽  
Surface Wind ◽  
Heat Fluxes ◽  
Lower Atmosphere ◽  
Meteorological Variables ◽  
Global Ocean ◽  
Study Region ◽  
Cold Core

The Brazil–Malvinas Confluence (BMC) is one of the most dynamical regions of the global ocean. Its variability is dominated by the mesoscale, mainly expressed by the presence of meanders and eddies, which are understood to be local regulators of air-sea interaction processes. The objective of this work is to study the local modulation of air-sea interaction variables by the presence of either a warm (ED1) and a cold core (ED2) eddy, present in the BMC, during September to November 2013. The translation and lifespans of both eddies were determined using satellite-derived sea level anomaly (SLA) data. Time series of satellite-derived surface wind data, as well as these and other meteorological variables, retrieved from ERA5 reanalysis at the eddies’ successive positions in time, allowed us to investigate the temporal modulation of the lower atmosphere by the eddies’ presence along their translation and lifespan. The reanalysis data indicate a mean increase of 78% in sensible and 55% in latent heat fluxes along the warm eddy trajectory in comparison to the surrounding ocean of the study region. Over the cold core eddy, on the other hand, we noticed a mean reduction of 49% and 25% in sensible and latent heat fluxes, respectively, compared to the adjacent ocean. Additionally, a field campaign observed both eddies and the lower atmosphere from ship-borne observations before, during and after crossing both eddies in the study region during October 2013. The presence of the eddies was imprinted on several surface meteorological variables depending on the sea surface temperature (SST) in the eddy cores. In situ oceanographic and meteorological data, together with high frequency micrometeorological data, were also used here to demonstrate that the local, rather than the large scale forcing of the eddies on the atmosphere above, is, as expected, the principal driver of air-sea interaction when transient atmospheric systems are stable (not actively varying) in the study region. We also make use of the in situ data to show the differences (biases) between bulk heat flux estimates (used on atmospheric reanalysis products) and eddy covariance measurements (taken as “sea truth”) of both sensible and latent heat fluxes. The findings demonstrate the importance of short-term changes (minutes to hours) in both the atmosphere and the ocean in contributing to these biases. We conclude by emphasizing the importance of the mesoscale oceanographic structures in the BMC on impacting local air-sea heat fluxes and the marine atmospheric boundary layer stability, especially under large scale, high-pressure atmospheric conditions.

scholarly journals Observation of Oceanic Eddy in the Northeastern Arabian Sea Using Multisensor Remote Sensing Data

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
R. K. Sarangi
Keyword(s):  
Remote Sensing ◽  
Arabian Sea ◽  
Chlorophyll Concentration ◽  
Climatic Conditions ◽  
Late Winter ◽  
Surrounding Water ◽  
Noaa Avhrr ◽  
Oceanic Eddy ◽  
Remote Sensing Satellite ◽  
Cold Core

An oceanic eddy of size about 150 kilometer diameter observed in the northeastern Arabian Sea using remote sensing satellite sensors; IRS-P4 OCM, NOAA-AVHRR and NASA Quickscat Scatterometer data. The eddy was detected in the 2nd week of February in Indian Remote Sensing satellite (IRS-P4) Ocean Color Monitor (OCM) sensor retrieved chlorophyll image on 10th February 2002, between latitude 16°90′–18°50′N and longitude 66°05′–67°60′E. The chlorophyll concentration was higher in the central part of eddy (~1.5 mg/m3) than the peripheral water (~0.8 mg/m3). The eddy lasted till 10th March 2002. NOAA-AVHRR sea surface temperature (SST) images generated during 15th February-15th March 2002. The SST in the eddy’s center (~23°C) was lesser than the surrounding water (~24.5°C). The eddy was of cold core type with the warmer water in periphery. Quickscat Scatterometer retrieved wind speed was 8–10 m/sec. The eddy movement observed southeast to southwest direction and might helped in churning. The eddy seemed evident due to convective processes in water column. The processes like detrainment and entrainment play role in bringing up the cooler water and the bottom nutrient to surface and hence the algal blooming. This type of cold core/anti-cyclonic eddy is likely to occur during late winter/spring as a result of the prevailing climatic conditions.

scholarly journals Horizontal refraction modeling of warm and cold core eddies

1978 ◽  
Vol 63 (S1) ◽  
pp. S71-S72 ◽  
Author(s):  
P. Scully‐Power ◽  
P. Nysen
Keyword(s):  
Horizontal Refraction ◽  
Cold Core

scholarly journals Footprints of triggering in large area surveys of the nearby ISM and YSOs

2006 ◽  
Vol 2 (S237) ◽  
pp. 124-127
Author(s):  
L. Viktor Tóth ◽  
Zoltán T. Kiss
Keyword(s):  
Star Formation ◽  
Stellar Evolution ◽  
Large Area ◽  
Large Sample ◽  
Low Mass ◽  
Cold Core

AbstractOur goal is to evaluate the role of triggering effects on the star formation and early stellar evolution by presenting a statistically large sample of cloud and low-mass YSO data. We conducted large area surveys (ranging from 400 square-degree to 10800 square-degree) in optical, NIR and FIR. The distribution of the ISM and low-mass YSOs were surveyed. A relative excess was found statistically in the number of dense and cold core bearing clouds and low mass YSOs in the direction of the FIR loop shells indicating a possible excess in their formation.

Copepods size structure in various phases of a cold-core eddy - Normalised Abundance Size Spectra (NASS) approach.

2020 ◽  
Vol 206 ◽  
pp. 104197
Author(s):  
L. Jagadeesan ◽  
T.N.R. Srinivas ◽  
A. Surendra ◽  
G. Sampath Kumar ◽  
M.P Aswindev ◽  
...  
Keyword(s):  
Size Structure ◽  
Size Spectra ◽  
Cold Core

scholarly journals Phytoplankton Increase Along the Kuroshio Due to the Large Meander

2021 ◽  
Vol 8 ◽  
Author(s):  
Daniel Andres Lizarbe Barreto ◽  
Ricardo Chevarria Saravia ◽  
Takeyoshi Nagai ◽  
Takafumi Hirata
Keyword(s):  
Chlorophyll A ◽  
Mixed Layer Depth ◽  
Local Environment ◽  
Trophic Levels ◽  
Large Meander ◽  
The Mean ◽  
Western Side ◽  
The Kuroshio ◽  
Cold Core ◽  
Kuroshio Region

The Kuroshio Large Meander (LM) is known to be highly aperiodic and can last from 1 to 10 years. Since a stationary cold core formed between the Kuroshio and the southern coast of Japan off Enshu-Nada and approaching warm saltier water on the eastern side of the LM changes the local environment drastically, many commercially valuable fish species distribute differently from the non-LM period, impacting local fisheries. Despite this importance of the LM, the influences of the LM on the low trophic levels such as phytoplankton and zooplankton have still been unclear. In this study, satellite daily sea surface chlorophyll data are analyzed in relation to the LM. The results show positive anomalies of the chlorophyll-a concentration along the Kuroshio path during the LM periods, 2004–2005 and 2017–2019, from the upstream off Shikoku to the downstream (140°E). These positive anomalies are started by the triggering meander generated off south of Kyushu, which then slowly propagates to the downstream LM region in both the LM periods. Even though the detailed patterns along the Kuroshio region in the two LM periods were different, similar formations of the positive anomalies on the western side of the LM with shallower mixed layer depth are observed. Furthermore, we found clear relationships between the minimum distance from several stations along the coast to the Kuroshio axis and the mean chlorophyll-a anomaly, with significant correlations with the distance from different stations.

scholarly journals C$^\mathsf{18}$O (3–2) observations of the Cometary Globule CG 12: a cold core and a C$^\mathsf{18}$O hot spot

2006 ◽  
Vol 454 (2) ◽  
pp. L71-L74 ◽  
Author(s):  
L. K. Haikala ◽  
M. Juvela ◽  
J. Harju ◽  
K. Lehtinen ◽  
K. Mattila ◽  
...  
Keyword(s):  
Hot Spot ◽  
Cold Core

A cyclone-centered perspective on the drivers of asymmetric patterns in the atmosphere and sea ice during Arctic cyclones

2021 ◽  
pp. 1-47
Author(s):  
Robin Clancy ◽  
Cecilia M. Bitz ◽  
Edward Blanchard-Wrigglesworth ◽  
Marie C. McGraw ◽  
Steven M. Cavallo
Keyword(s):  
Sea Ice ◽  
Spatial Patterns ◽  
The West ◽  
Sea Ice Concentration ◽  
Sea Ice Thickness ◽  
Ice Concentration ◽  
Primary Driver ◽  
The Impact ◽  
Cold Core ◽  
East West

AbstractArctic cyclones are an extremely common, year-round phenomenon, with substantial influence on sea ice. However, few studies address the heterogeneity in the spatial patterns in the atmosphere and sea ice during Arctic cyclones. We investigate these spatial patterns by compositing on cyclones from 1985-2016 using a novel, cyclone-centered approach that reveals conditions as functions of bearing and distance from cyclone centers. An axisymmetric, cold core model for the structure of Arctic cyclones has previously been proposed, however, we show that the structure of Arctic cyclones is comparable to those in the mid-latitudes, with cyclonic surface winds, a warm, moist sector to the east of cyclones and a cold, dry sector to the west. There is no consensus on the impact of Arctic cyclones on sea ice, as some studies have shown that Arctic cyclones lead to sea ice growth and others to sea ice loss. Instead, we find that sea ice decreases to the east of Arctic cyclones and increases to the west, with the greatest changes occurring in the marginal ice zone. Using a sea ice model forced with prescribed atmospheric reanalysis, we reveal the relative importance of the dynamic and thermodynamic forcing of Arctic cyclones on sea ice. The dynamic and thermodynamic responses of sea ice concentration to cyclones are comparable in magnitude, however dynamic processes dominate the response of sea ice thickness and are the primary driver of the east-west difference in the sea ice response to cyclones.

Heat

2020 ◽  
pp. 1687-1689
Author(s):  
Michael A. Stroud
Keyword(s):  
Physical Activity ◽  
Body Temperature ◽  
Supportive Care ◽  
Physiological Responses ◽  
Heat Stroke ◽  
Heat Exposure ◽  
High Humidity ◽  
Heat Exhaustion ◽  
Clinical Presentations ◽  
Cold Core

Rising body temperature triggers behavioural and physiological responses including reduction in physical activity, alterations of clothing, skin vasodilatation, and sweating. Heat-related illness is relatively common, especially with high humidity or prolonged physical activity. Risk can be reduced by acclimatization with repeated heat exposure, but some individuals seem to be particularly susceptible. Clinical presentations of heat-related illness include (1) ‘heat exhaustion’—the commonest manifestation, with symptoms including nausea, weakness, headache, and thirst. Patients appear dehydrated, complain of being hot, and are flushed and sweaty. Treatment requires rest and fluids, given orally or (in severe cases) intravenously. (2) ‘Heat stroke’ victims often complain of headache, may be drowsy or irritable, and may claim to feel cold. Core temperature is usually 38–41°C, but the patient is shivering with dry, vasoconstricted skin. Treatment requires (a) aggressive rapid cooling; (b) close biochemical monitoring; (c) supportive care for organ failure. There is significant mortality.

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