scholarly journals The oceanographic contribution of James Croll

2021 ◽  
pp. 1-7
Author(s):  
Alastair DAWSON
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
First Principles ◽  
Heat Supply ◽  
Real Data ◽  
Ocean Currents ◽  
Ice Ages ◽  
Scientific Exploration ◽  
The Many

ABSTRACT The research of James Croll on the nature of Ice Ages led him into a detailed investigation of ocean currents. By the early 1870s he had calculated from first principles the quantities of heat delivered by ocean currents to high latitude areas and he understood how this heat supply may have altered drastically during ice ages. The publication of his many papers on ocean currents as well as his book, Climate and Time, coincided with Challenger expedition that, in 1872, embarked on a 4-year voyage of scientific exploration of the world's oceans. The expedition was crucially important for Croll since it enabled him to test his theories of ocean circulation using real data. His novel theories of ocean circulation based on this information conflicted with the established views popularly advocated by William Carpenter but they ultimately prevailed. In the many writings of Croll on ocean currents, we encounter, as with other areas of his research, numerous remarkable ideas many decades ahead their time.

scholarly journals Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jussi Hovikoski ◽  
Michael B. W. Fyhn ◽  
Henrik Nøhr-Hansen ◽  
John R. Hopper ◽  
Steven Andrews ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
High Latitude ◽  
Seismic Reflection ◽  
Arctic Region ◽  
Climatic Conditions ◽  
The Arctic ◽  
Early Eocene ◽  
Subaerial Exposure ◽  
Thermal Maximum ◽  
Volcanic Facies

AbstractThe paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins. We identify Paleocene–Eocene uplift that culminated in widespread regression, volcanism, and subaerial exposure during the Ypresian. We reconstruct the paleogeography of the northeast Atlantic–Arctic region and propose that this uplift led to fragmentation of the Norwegian–Greenland seaway during this period. We suggest that the seaway became severely restricted between about 56 and 53 million years ago, effectively isolating the Arctic from the Atlantic ocean during the Paleocene–Eocene thermal maximum and the early Eocene.

scholarly journals Buried Ancient Forest and Implications for Paleoclimate Since the Mid-Holocene in South China

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1411-1421 ◽  
Author(s):  
C D Shen ◽  
P Ding ◽  
N Wang ◽  
W X Yi ◽  
X F Ding ◽  
...  
Keyword(s):  
South China ◽  
High Latitude ◽  
Silty Clay ◽  
Historical Evolution ◽  
Ice Ages ◽  
Climate Fluctuations ◽  
Ancient Forest ◽  
Clay Layers

The historical evolution of an ancient forest that developed at Gaoyao, south China, can be divided into 4 stages of radiocarbon intervals (1.1–1.5, 2.0–3.5, 3.6–4.0, and 4.3–4.9 ka) in which the last 3 stages all developed in a wetland and formed humic layers of 2.0, 0.5, and 0.7 m depth, respectively. The humic layers were interrupted by 2 white-gray silty clay layers that most likely formed during climate fluctuations. Four drought events were identified during the evolution of the ancient forest, occurring around 4.3, 3.6, 2.0, and 1.1 ka, respectively, with durations of ∼1000 14C yr. These events are consistent with other records both in low- and high-latitude areas, in particular with the little ice ages occurring since the mid-Holocene. Precipitation likely increased from 5.0 to 3.6 ka in south China, then decreased, which is probably the main cause for the development as well as the demise of the ancient forest.

scholarly journals Upper-Bound General Circulation of the Ocean: a Theoretical Exposition

2021 ◽  
Author(s):  
Hsien-Wang Ou
Keyword(s):  
Ocean Circulation ◽  
Upper Bound ◽  
First Principles ◽  
General Circulation ◽  
Large Scale ◽  
Companion Paper ◽  
Jet Stream ◽  
Equatorial Undercurrent ◽  
Macroscopic Motion ◽  
Dynamical Principle

This paper considers the general ocean circulation within the thermodynamical closure of our climate theory, which aims to deduce the generic climate state from first principles. The preceding papers of the theory have reduced planetary fluids to warm/cold masses and determined their bulk thermal properties, which provide prior constraints for the derivation of the upper-bound circulation when the potential vorticity is homogenized in moving masses. In a companion paper on the atmosphere, this upper bound is seen to reproduce the prevailing wind, forsaking therefore previous discordant explanations of the easterly trade and the polar jet stream. In this paper on the ocean, we again show that this upper bound may replicate broad features of the observed circulation, including a western-intensified subtropical gyre and a counter-rotating tropical gyre feeding the equatorial undercurrent. Together, we posit that PV homogenization may provide a unifying dynamical principle of the large-scale planetary circulation, which may be interpreted as the maximum macroscopic motion extractable by microscopic stirring --- within the confine of the thermal differentiation.

scholarly journals <i>Brief communication</i> "The 2013 Erebus Glacier tongue calving event"

2013 ◽  
Vol 7 (2) ◽  
pp. 1749-1760
Author(s):  
C. L. Stevens ◽  
P. Sirguey ◽  
G. H. Leonard ◽  
T. G. Haskell
Keyword(s):  
Ocean Circulation ◽  
Ocean Currents ◽  
Mcmurdo Sound ◽  
Glacier Tongue ◽  
Surface Ocean ◽  
Fast Ice

Abstract. The Erebus Glacier Tongue, a~small floating glacier in southern McMurdo Sound, is one of the best-studied ice tongues in Antarctica. Despite this, its calving on the 27 February 2013 (UTC) was around 10 yr earlier than previously predicted. The calving was likely a result of ocean currents and the absence of fast ice. The subsequent trajectory of the newly-created iceberg supports previous descriptions of the surface ocean circulation in southern McMurdo Sound.

scholarly journals A Non-Linear Autoregressive Model for Indoor Air-Temperature Predictions in Smart Buildings

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 979 ◽  
Author(s):  
Alessandro Aliberti ◽  
Lorenzo Bottaccioli ◽  
Enrico Macii ◽  
Santa Di Cataldo ◽  
Andrea Acquaviva ◽  
...  
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Decisive Role ◽  
Real Data ◽  
Total Energy Consumption ◽  
Innovative Methodology ◽  
Non Linear ◽  
Temperature Forecasting ◽  
Iot Devices ◽  
The Many

In recent years, the contrast against energy waste and pollution has become mandatory and widely endorsed. Among the many actors at stake, the building sector energy management is one of the most critical. Indeed, buildings are responsible for 40 % of total energy consumption only in Europe, affecting more than a third of the total pollution produced. Therefore, energy control policies of buildings (for example, forecast-based policies such as Demand Response and Demand Side Management) play a decisive role in reducing energy waste. On these premises, this paper presents an innovative methodology based on Internet-of-Things (IoT) technology for smart building indoor air-temperature forecasting. In detail, our methodology exploits a specialized Non-linear Autoregressive neural network for short- and medium-term predictions, envisioning two different exploitation: (i) on realistic artificial data and (ii) on real data collected by IoT devices deployed in the building. For this purpose, we designed and optimized four neural models, focusing respectively on three characterizing rooms and on the whole building. Experimental results on both a simulated and a real sensors dataset demonstrate the prediction accuracy and robustness of our proposed models.

scholarly journals Can the Subtropical North Atlantic permanent thermocline be observed from space?

2002 ◽  
Vol 82 (5) ◽  
pp. 709-728 ◽  
Author(s):  
Robin Pingree ◽  
Yu-Heng Kuo ◽  
Carlos Garcia-Soto
Keyword(s):  
Sea Level ◽  
Ocean Circulation ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Remotely Sensed ◽  
Ocean Currents ◽  
Maximum Temperature ◽  
Altimeter Data ◽  
Sea Level Anomaly

The analysis of remotely sensed altimeter data and in situ measurements shows that ERS 2 radar can monitor the ocean permanent thermocline from space. The remotely sensed sea level anomaly data account for ∼2/3 of the temperature variance or vertical displacement of isotherms at a depth of ∼550 m in the Subtropical North Atlantic Ocean near 32·5°N. This depth corresponds closely to the region of maximum temperature gradient in the permanent thermocline where near semi-annual internal vertical displacements reach 200 to 300 m. The gradient of the altimeter sea level anomaly data correlates well with measured ocean currents to a depth of 750 m. It is shown that observations from space can account for ∼3/4 of the variance of ocean currents measured in situ in the permanent thermocline over a 2-y period. The magnification of the permanent thermocline displacement with respect to the displacement of the sea surface was determined as −×650 and gives a measure of the ratio of barotropic to baroclinic decay scale of geostrophic current with depth. The overall results are used to interpret an eight year altimeter data time series in the Subtropical North Atlantic at 32·5°N which shows a dominant wave or eddy period near 200 days, rather than semi-annual and increases in energy propagating westward in 1995 (west of 25°W). The effects of rapid North Atlantic Oscillation climate change on ocean circulation are discussed. The altimeter data for the Atlantic were Fourier analysed. It is shown how the annual and semi-annual components relate to the seasonal maximum cholorophyll-a SeaWiFS signal in tropical and equatorial regions due to the lifting of the thermocline caused by seasonally varying ocean currents forced by wind stress.

The quantum second virial coefficient of 3He at low density in the temperature range 0.005–10 K

2017 ◽  
Vol 95 (12) ◽  
pp. 1208-1214 ◽  
Author(s):  
O.T. Al-Obeidat ◽  
A.S. Sandouqa ◽  
B.R. Joudeh ◽  
H.B. Ghassib ◽  
M.M. Hawamdeh
Keyword(s):  
First Principles ◽  
Virial Coefficient ◽  
Scattering Length ◽  
Second Virial Coefficient ◽  
Repulsive Interaction ◽  
Saturation Curve ◽  
Low Density ◽  
S Wave ◽  
Temperature Range ◽  
The Many

The quantum second virial coefficient Bq for 3He is calculated from first principles at low density in the temperature range 0.005–10 K. By “first principles”, it is meant that the many-body phase shifts are first determined within the Galitskii–Migdal–Feynman formalism; they are then plugged into the Beth–Uhlenbeck formula for Bq. A positive Bq corresponds to an overall repulsive interaction; a negative Bq represents an overall attractive interaction. The s-wave scattering length a0 is calculated quite accurately as a function of the temperature T. The effect of the (low-density) medium on Bq is studied. Bq is then used to determine the volume of 3He at the saturation curve. The compressibility is evaluated as a measure of the non-ideality of the system.

scholarly journals Computer Simulations of the Influence of Ocean Currents on Fraser River Sockeye Salmon (Oncorhynchus nerka) Return Times

1994 ◽  
Vol 51 (2) ◽  
pp. 441-449 ◽  
Author(s):  
Keith A. Thomson ◽  
W. James Ingraham Jr. ◽  
Michael C. Healey ◽  
Paul H. LeBlond ◽  
Cornelius Groot ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Return Migration ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Vancouver Island ◽  
Ocean Currents ◽  
Fraser River ◽  
Return Times ◽  
Gyre Circulation ◽  
Model Fish

We hypothesized that the interannual variability of the northeast Pacific Ocean circulation affects the return times of Fraser River sockeye salmon (Oncorhynchus nerka). Homeward migrations were simulated for 1982 (with a relatively weak Alaska Gyre circulation) and 1983 (with a relatively strong circulation) in the context of three sequential return migration phases: a nondirected oceanic phase, a directed oceanic phase, and a directed coastal phase. Passive drifters were simulated to examine the influence of ocean currents during the nondirected oceanic phase: model fish south of 48°N were advected closer to Vancouver Island in 1983 compared with 1982; those north of 48°N were advected closer to Vancouver Island in 1982 than in 1983. Fish were simulated during the directed oceanic phase using a variety of behaviour scenarios: model fish starting south of 50°N had earlier return times in 1983 than in 1982; those starting north of 50°N had return times in 1983 that were generally the same as or later than in 1982. We inferred that ocean currents would modulate the environmental influences on return times during the directed coastal migration phase, by deflecting sockeye salmon into different oceanographic domains along the British Columbia coast.

scholarly journals Heterogeneous resource allocation can change social hierarchy in public goods games

2017 ◽  
Vol 4 (3) ◽  
pp. 170092 ◽  
Author(s):  
Sandro Meloni ◽  
Cheng-Yi Xia ◽  
Yamir Moreno
Keyword(s):  
Public Goods ◽  
First Principles ◽  
Pareto Distribution ◽  
Wealth Distribution ◽  
Real Data ◽  
Group Interactions ◽  
Classical Formulation ◽  
Public Goods Games ◽  
Typical Shape ◽  
Key Features

Public goods games (PGGs) represent one of the most useful tools to study group interactions. However, even if they could provide an explanation for the emergence and stability of cooperation in modern societies, they are not able to reproduce some key features observed in social and economical interactions. The typical shape of wealth distribution—known as Pareto Law—and the microscopic organization of wealth production are two of them. Here, we introduce a modification to the classical formulation of PGGs that allows for the emergence of both of these features from first principles. Unlike traditional PGGs, where players contribute equally to all the games in which they participate, we allow individuals to redistribute their contribution according to what they earned in previous rounds. Results from numerical simulations show that not only a Pareto distribution for the pay-offs naturally emerges but also that if players do not invest enough in one round they can act as defectors even if they are formally cooperators. Our results not only give an explanation for wealth heterogeneity observed in real data but also point to a conceptual change on cooperation in collective dilemmas.

scholarly journals A many-particle approach to the gyro-kinetic theory

2007 ◽  
Vol 73 (5) ◽  
pp. 757-772 ◽  
Author(s):  
ALEXEY MISHCHENKO ◽  
AXEL KÖNIES
Keyword(s):  
Kinetic Equation ◽  
Kinetic Theory ◽  
First Principles ◽  
Conventional Approach ◽  
The Self ◽  
Collision Term ◽  
Lie Transform ◽  
Self Consistent ◽  
The Many ◽  
Particle Approach

AbstractA systematic first-principles approach to the many-particle formulation of the gyro-kinetic theory is suggested. The gyro-kinetic many-particle Hamiltonian is derived using the Lie transform technique. The generalized gyro-kinetic equation is obtained following the Born–Bogoliubov–Green–Kirkwood–Yvon approach. The microscopic expression for the self-consistent potential and the polarization density is obtained. It is shown that new terms appear in the gyro-kinetic polarization that can not be derived in the conventional approach. An expression for the collision term is obtained in the Landau approximation.

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