scholarly journals Interglacials, Milankovitch Cycles, Solar Activity, and Carbon Dioxide

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Gerald E. Marsh
Keyword(s):  
Carbon Dioxide ◽  
Solar Activity ◽  
North Atlantic ◽  
Atmospheric Carbon Dioxide ◽  
Milankovitch Cycles ◽  
The North ◽  
The Pacific ◽  
Carbon Dioxide Concentrations ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions.

scholarly journals The influence of solar activity on action centres of atmospheric circulation in North Atlantic

2015 ◽  
Vol 33 (2) ◽  
pp. 207-215 ◽  
Author(s):  
L. Sfîcă ◽  
M. Voiculescu ◽  
R. Huth
Keyword(s):  
Solar Activity ◽  
Sea Level ◽  
North Atlantic ◽  
High Solar Activity ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
The Pacific ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract. We analyse the response of sea level pressure and mid-tropospheric (500 hPa) geopotential heights to variations in solar activity. We concentrate on the Northern Hemisphere and North Atlantic in the period 1948–2012. Composite and correlation analyses point to a strengthening of the North Atlantic Oscillation and weakening (i.e. becoming more zonal) of the Pacific/North American pattern. The locations of points with lowest and highest sea level pressure in the North Atlantic change their positions between low and high solar activity.

scholarly journals Multi-decadal uptake of carbon dioxide into subtropical mode water of the North Atlantic Ocean

2011 ◽  
Vol 8 (6) ◽  
pp. 12451-12476 ◽  
Author(s):  
N. R. Bates
Keyword(s):  
Carbon Dioxide ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Dissolved Inorganic Carbon ◽  
Mode Water ◽  
Subtropical Mode Water ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract. Natural climate variability impacts the multi-decadal uptake of anthropogenic carbon dioxide (Cant) into the North Atlantic Ocean subpolar and subtropical gyres. Previous studies have shown that there is significant uptake of CO2 into the subtropical mode water (STMW) that forms south of the Gulf Stream in winter and constitutes the dominant upper-ocean water mass in the subtropical gyre of the North Atlantic Ocean. Observations at the Bermuda Atlantic Time-series Study (BATS) site near Bermuda show an increase in dissolved inorganic carbon (DIC) of +1.51 ± 0.08 μmol kg−1 yr−1 between 1988 and 2011. It is estimated that the sink of CO2 into STMW was 0.985 ± 0.018 Pg C (Pg = 1015 g C) between 1988 and 2011 (~70 % of which is due to uptake of Cant). However, the STMW sink of CO2 was strongly coupled to the North Atlantic Oscillation (NAO) with large uptake of CO2 into STMW during the 1990s (NAO positive phase). In contrast, uptake of CO2 into STMW was much reduced in the 2000s during the NAO neutral/negative phase. Thus, NAO induced variability of the STMW CO2 sink is important when evaluating multi-decadal changes in North Atlantic Ocean CO2 sinks.

On the Role of Atmospheric Teleconnections in Climate

2008 ◽  
Vol 21 (12) ◽  
pp. 2990-3001 ◽  
Author(s):  
Anastasios A. Tsonis ◽  
Kyle L. Swanson ◽  
Geli Wang
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Recent Application ◽  
The North ◽  
The Pacific ◽  
Atmospheric Teleconnections ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Tropics

Abstract In a recent application of networks to 500-hPa data, it was found that supernodes in the network correspond to major teleconnection. More specifically, in the Northern Hemisphere a set of supernodes coincides with the North Atlantic Oscillation (NAO) and another set is located in the area where the Pacific–North American (PNA) and the tropical Northern Hemisphere (TNH) patterns are found. It was subsequently suggested that the presence of atmospheric teleconnections make climate more stable and more efficient in transferring information. Here this hypothesis is tested by examining the topology of the complete network as well as of the networks without teleconnections. It is found that indeed without teleconnections the network becomes less stable and less efficient in transferring information. It was also found that the pattern chiefly responsible for this mechanism in the extratropics is the NAO. The other patterns are simply a linear response of the activity in the tropics and their role in this mechanism is inconsequential.

scholarly journals Atmospheric and Ocean Dynamics May Explain Cycles in Oceanic Oscillations

Climate ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 77
Author(s):  
Knut L. Seip ◽  
Øyvind Grøn
Keyword(s):  
North Atlantic ◽  
Southern Oscillation ◽  
Distinct Pattern ◽  
Ocean Dynamics ◽  
Cyclic Pattern ◽  
The North ◽  
The Pacific ◽  
Cycle Lengths ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

What causes cycles in oceanic oscillations, and is there a change in the characteristics of oscillations in around 1950? Characteristics of oceanic cycles and their sources are important for climate predictability. We here compare cycles generated in a simple model with observed oceanic cycles in the great oceans: The North Atlantic Oscillation (NAO), El Niño, the Southern Oscillation Index (SOI), and the Pacific Decadal Oscillation (PDO). In the model, we let a stochastic movement in one oceanic oscillation cause a similar but lagging movement in another oceanic oscillation. The two interacting oscillations show distinct cycle lengths depending upon how strongly one oscillation creates lagging cycles in the other. The model and observations both show cycles around two to six, 13 to 16, 22 to 23, and 31 to 32 years. The ultimate cause for the distinct cycles is atmospheric and oceanic “bridges” that connect the ocean basins, but the distinct pattern in cycle lengths is determined by properties of statistical distributions. We found no differences in the leading or lagging strength between well separated basins (the North Atlantic and the Pacific) and overlapping ocean basins (both in the Pacific). The cyclic pattern before 1950 appears to be different from the cyclic pattern after 1950.

Variability of the North Atlantic response to sudden stratospheric warming events in a simplified atmospheric model

2020 ◽  
Author(s):  
Hilla Afargan-Gerstman ◽  
Bernat Jiménez-Esteve ◽  
Daniela I.V. Domeisen
Keyword(s):  
North Atlantic ◽  
Atmospheric Model ◽  
Negative Phase ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Large Variability ◽  
The North ◽  
The Pacific ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

<p>Sudden stratospheric warming (SSW) events are often followed by a surface impact, most commonly by a negative phase of the North Atlantic Oscillation (NAO). Recent work has emphasized the large variability among the tropospheric response after these events, showing that only about two thirds of the SSWs are dominated by this canonical negative NAO response. In this study, we use an idealized atmospheric model forced with seasonally varying sea surface temperatures to examine the influence of the pre-existing tropospheric conditions on the North Atlantic response to stratospheric forcing. In the model, the negative phase of the NAO is found to be the most common response to SSWs, occurring after ~85% of the SSWs (under climatological SST forcing).  For the remaining ~15% of the SSW events, the response is associated with a positive phase of the NAO. In the search for the origin of the different tropospheric response in the North Atlantic, the role of synoptic wave propagation from the eastern Pacific on the downward response to SSWs is investigated. By systematically varying the strength of the North Pacific circulation, we are able to assess the sensitivity of the downward response to tropospheric variability in the Pacific, and shed light on its contribution to the persistence of the downward impact of SSWs in the idealized model.</p>

scholarly journals On the Structure and Teleconnections of North Atlantic Decadal Variability

2011 ◽  
Vol 24 (9) ◽  
pp. 2209-2223 ◽  
Author(s):  
Francisco J. Álvarez-García ◽  
María J. OrtizBevia ◽  
William D. CabosNarvaez
Keyword(s):  
North Atlantic ◽  
Time Scale ◽  
Decadal Variability ◽  
The North ◽  
The Pacific ◽  
Tropical North Atlantic ◽  
Decadal Variations ◽  
The Pacific Ocean ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Decadal variability in the North Atlantic has been associated in the literature with a tripolar pattern of sea surface temperature (SST) anomalies that show one sign in the western midlatitudinal North Atlantic and the opposite in the subpolar and tropical North Atlantic. The present analysis of observed SST from 1870 to 2009 leads to the dissection of the SST tripole into two components, each with a different time scale in the decadal band and different teleconnections in the Atlantic basin; while the subpolar and tropical poles present quasi-decadal variations with a period of about 9 years, essentially uncorrelated with other parts of the basin, the center of action in the western midlatitudes is characterized by a longer time scale of about 14 years and significant correlations with the tropical South Atlantic and the Norwegian and North Sea(s). The 9-yr period variations are associated with an atmospheric configuration resembling the east Atlantic pattern, whereas the 14-yr period fluctuations seem to be related to the North Atlantic Oscillation pattern. Each component also bears a different relationship with the decadal variability in the Pacific Ocean.

Sign in / Sign up

Export Citation Format

Share Document