On the Joint Role of Subtropical Atmospheric Variability and Equatorial Subsurface Heat Content Anomalies in Initiating the Onset of ENSO Events

2007 ◽  
Vol 20 (8) ◽  
pp. 1593-1599 ◽  
Author(s):  
Bruce T. Anderson
Keyword(s):  
Sea Level ◽  
North Pacific ◽  
Heat Content ◽  
Equatorial Pacific ◽  
Boreal Winter ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
Enso Events ◽  
Western Equatorial Pacific ◽  
Central North Pacific

Abstract Previous research has shown that seasonal mean variations in both the subtropical/extratropical sea level pressures over the central North Pacific and the subsurface heat content anomalies in the western equatorial Pacific are significantly related to the state of the El Niño–Southern Oscillation (ENSO) 12–18 months later. Here we find that positive (negative) subsurface temperature anomalies in the western equatorial Pacific during boreal summer/fall, followed by negative (positive) anomalies in the sea level pressure fields over the subtropical central North Pacific during boreal winter, tend to result in positive (negative) mature ENSO events 12–15 months later (i.e., during the following boreal winter). When the intervening sea level pressure anomalies are of the same sign as the preceding heat-content anomalies, the correlation between the heat-content anomalies and the following boreal-winter ENSO state disappears. There is still some relation between the boreal-winter sea level pressure anomalies and the ENSO state the following year when the two precursor patterns are of the same sign; however, the correlation is smaller and the ENSO events tend to be weaker. Additional analysis indicates that the two precursor fields are related to one another; however, the sea level pressure variations contain more unique information about, and provide better predictability of, the state of the following ENSO system than do the heat content anomalies.

scholarly journals New Insights into Annual and Semiannual Cycles of Sea Level Pressure

2012 ◽  
Vol 140 (4) ◽  
pp. 1347-1355 ◽  
Author(s):  
Ge Chen ◽  
Chengcheng Qian ◽  
Caiyun Zhang
Keyword(s):  
Sea Level ◽  
Southern Oscillation ◽  
Global Ocean ◽  
Boreal Winter ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
Dominant Feature ◽  
The One ◽  
The North Pacific

Sea level pressure (SLP) acts, on the one hand, as a “bridge parameter” to which geophysical properties at the air–sea interface (e.g., wind stress and sea surface height) are linked, and on the other hand, as an “index parameter” by which major atmospheric oscillations, including the well-known Southern Oscillation, are defined. Using 144 yr (1854–1997) of extended reconstructed SLP data, seasonal patterns of its variability are reinvestigated in detail. New features on fundamental structure of its annual and semiannual cycles are revealed in two aspects. First, the spatiotemporal patterns of yearly and half-yearly SLPs are basically determined by a network of “amphidromes,” which are surrounded by rotational variations. Fourteen cyclonic and anticyclonic annual SLP amphidromes (half each and often in pair) are found in the global ocean, while the numbers of the two types of semiannual amphidrome are 11 and 9, respectively. The second dominant feature in SLP variability is the pattern of oscillation or seesaw for both annual and semiannual components. At least eight oscillation zones are identified for the annual cycle, which can be categorized into a boreal winter mode and an austral winter mode. As for the semiannual cycle, the seesaw pattern is geographically divided into three regimes: the North Pacific regime, the North Atlantic regime, and the Southern Ocean regime. These findings serve as a new contribution to characterizing and understanding the seasonality of the global ocean–atmosphere system.

scholarly journals The Victoria mode in the North Pacific linking extratropical sea level pressure variations to ENSO

2015 ◽  
Vol 120 (1) ◽  
pp. 27-45 ◽  
Author(s):  
Ruiqiang Ding ◽  
Jianping Li ◽  
Yu-heng Tseng ◽  
Cheng Sun ◽  
Yipeng Guo
Keyword(s):  
Sea Level ◽  
North Pacific ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
The North Pacific

scholarly journals Future changes in Beijing haze events under different anthropogenic aerosol emission scenarios

2021 ◽  
Vol 21 (10) ◽  
pp. 7499-7514
Author(s):  
Lixia Zhang ◽  
Laura J. Wilcox ◽  
Nick J. Dunstone ◽  
David J. Paynter ◽  
Shuai Hu ◽  
...  
Keyword(s):  
Sea Level ◽  
Atmospheric Circulation ◽  
North Pacific ◽  
Anthropogenic Aerosol ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
Aerosol Emission ◽  
Circulation Patterns ◽  
The North Pacific

Abstract. Air pollution is a major issue in China and one of the largest threats to public health. We investigated future changes in atmospheric circulation patterns associated with haze events in the Beijing region and the severity of haze events during these circulation conditions from 2015 to 2049 under two different aerosol scenarios: a maximum technically feasible aerosol reduction (MTFR) and a current legislation aerosol scenario (CLE). In both cases greenhouse gas emissions follow the Representative Concentration Pathway 4.5 (RCP4.5). Under RCP4.5 with CLE aerosol the frequency of circulation patterns associated with haze events increases due to a weakening of the East Asian winter monsoon via increased sea level pressure over the North Pacific. The rapid reduction in anthropogenic aerosol and precursor emissions in MTFR further increases the frequency of circulation patterns associated with haze events, due to further increases in the sea level pressure over the North Pacific and a reduction in the intensity of the Siberian high. Even with the aggressive aerosol reductions in MTFR periods of poor visibility, represented by above-normal aerosol optical depth (AOD), still occur in conjunction with haze-favorable atmospheric circulation. However, the winter mean intensity of poor visibility decreases in MTFR, so that haze events are less dangerous in this scenario by 2050 compared to CLE and relative to the current baseline. This study reveals the competing effects of aerosol emission reductions on future haze events through their direct contribution to pollutant source and their influence on the atmospheric circulation. A compound consideration of these two impacts should be taken in future policy making.

The North Pacific Climate Transitions of the Winters of 1976/77 and 1988/89

2011 ◽  
Vol 24 (4) ◽  
pp. 1170-1183 ◽  
Author(s):  
Sang-Wook Yeh ◽  
Yune-Jung Kang ◽  
Yign Noh ◽  
Arthur J. Miller
Keyword(s):  
Sea Level ◽  
North Pacific ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
The North ◽  
Sst Variability ◽  
Transition Project ◽  
Climate Transition ◽  
The Tropics ◽  
The North Pacific

Abstract This paper examines characteristic changes in North Pacific sea surface temperature (SST) variability during the boreal winter (December–February) for two subperiods (1956–88 and 1977–2009) during which the 1976/77 and the 1988/89 climate transitions occurred. It is found that the Pacific decadal oscillation (PDO)-like SST variability plays a dominant role in the 1976/77 climate transition, while both the North Pacific Gyre Oscillation (NPGO)-like and PDO-like SST variability contribute to the 1988/89 climate transition. Furthermore, the leading mode changes from PDO-like SST variability during the period 1956–88 to NPGO-like SST variability during the period 1977–2009, indicative of an enhancement of NPGO-like SST variability since 1988. Changes in sea level pressure across the 1976/77 climate transition project strongly onto the Aleutian low pressure system. But sea level pressure changes across the 1988/89 climate transition project primarily onto the North Pacific Oscillation, which is associated with remote changes in the Arctic Oscillation over the polar region as well. This contributes to enhancing the NPGO-like SST variability after 1988. The authors also analyze the output from an ensemble of Tropical Ocean and Global Atmosphere (TOGA) experiments in which the observed SSTs are inserted only at grid points in the tropics between 20°S and 20°N. The results indicate that the changes in the North Pacific atmosphere in the 1976/77 climate transition are mostly due to the tropics, whereas those in the 1988/89 climate transition are not.

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