A recent change in the mean state of the Pacific basin climate: Observational evidence and atmospheric and oceanic responses

1996 ◽  
Vol 101 (C9) ◽  
pp. 20483-20499 ◽  
Author(s):  
Richard Kleeman ◽  
Robert A. Colman ◽  
Neville R. Smith ◽  
Scott B. Power
Keyword(s):  
Recent Change ◽  
Observational Evidence ◽  
Pacific Basin ◽  
The Pacific ◽  
Change In The Mean ◽  
The Mean ◽  
Mean State

Interdecadal changes in the interannual variability of the summer temperature over Northeast Asia

2021 ◽  
pp. 1-50
Author(s):  
Ruidan Chen ◽  
Zhiping Wen ◽  
Riyu Lu ◽  
Wenjun Liu
Keyword(s):  
Interannual Variability ◽  
Northeast Asia ◽  
Tropical Indian Ocean ◽  
Summer Temperature ◽  
Atmospheric Variability ◽  
The Pacific ◽  
The Mean ◽  
Southeastern Tropical Indian Ocean ◽  
Interdecadal Changes ◽  
Mean State

AbstractThis study reveals the interdecadal changes in the interannual variability of the summer temperature over Northeast Asia (NEA), which presents an enhancement around the early 1990s and a reduction after the mid-2000s. The stronger NEA temperature variability after the early 1990s is favored by the enhanced influence of the Pacific–Japan (PJ) teleconnection, which is remotely modulated by the southeastern tropical Indian Ocean (SETIO). After the early 1990s, the mean state over the SETIO presents relatively warmer SST and ascending motion, favoring a good relationship between the local SST and convection. Therefore, the SETIO SST could prominently influence the local convection and subsequently modulate the convection over the western North Pacific (WNP) via a cross-equatorial overturning circulation. The abnormal convection over the WNP further triggers the PJ teleconnection to influence NEA. However, these ocean–atmosphere processes disappear before the early 1990s. In this period, the mean state over the SETIO features relatively colder SST and subsiding motion, accompanied by a poor relationship between the local SST and convection. Therefore, the variability of convection over the SETIO is weak, thus the atmospheric variability over the WNP is also weakened and the PJ teleconnection presents a different distribution that could not influence NEA. The reduced variability of NEA temperature after the mid-2000s is related to the feeble influence of the PJ teleconnection and the reduced variability of the SETIO SST, which is modulated by the SST over the tropical central–eastern Pacific during the preceding winter to spring.

scholarly journals Relations between Annular Modes and the Mean State: Southern Hemisphere Winter

2007 ◽  
Vol 64 (9) ◽  
pp. 3328-3339 ◽  
Author(s):  
Francis Codron
Keyword(s):  
Southern Hemisphere ◽  
Low Frequency ◽  
Stationary Waves ◽  
Annular Modes ◽  
The Pacific ◽  
Latitudinal Shift ◽  
The Indian Ocean ◽  
The Mean ◽  
Hemisphere Winter ◽  
Mean State

Abstract In a zonally symmetric climatology with a single eddy-driven jet, such as prevails in the Southern Hemisphere summer, the midlatitude variability is dominated by fluctuations of the jet around its mean position, as described by the Southern Hemisphere annular mode (SAM). To study whether this result holds for a zonally asymmetric climatology, the observed variability of the Southern Hemisphere winter is analyzed. The mean state in this case is characterized by relatively weak stationary waves; yet there exist significant zonal variations in the mean strength and meridional structure of the subtropical jet stream. As in summer, the winter SAM signature is annular in shape and the corresponding wind anomalies are dipolar; but it is associated with two different behaviors of the eddy-driven jet in different longitudinal ranges. Over the Indian Ocean, the SAM is associated primarily with a latitudinal shift of the jet around its mean position. Over the Pacific sector, it is instead characterized by a seesaw in the wind speed between two distinct latitudes, corresponding to the positions of the midlatitude and subtropical jets. Composites of eddy forcing and baroclinicity over both sectors appear consistent with the two different behaviors. As in the zonal-mean case, high-frequency eddies both force and maintain the low-frequency wind anomalies associated with the SAM. The positive feedback by eddies is, however, not local: changes in the eddy forcing are influenced most strongly by zonal wind anomalies located upstream.

The intelligence of six-year-olds in Hong Kong

1989 ◽  
Vol 21 (4) ◽  
pp. 461-464 ◽  
Author(s):  
Jimmy Chan ◽  
Richard Lynn
Keyword(s):  
United States ◽  
Hong Kong ◽  
Ethnic Minorities ◽  
The United States ◽  
Chinese Children ◽  
Pacific Basin ◽  
The Pacific ◽  
The Us ◽  
The Mean ◽  
The Uk

SummaryEvidence has accumulated to suggest that the mean IQs of Orientals in the United States and in the countries of the Pacific Basin are higher than those of Whites (Caucasoids) in the United States and Britain. This paper presents evidence from IQ tests on 4858 6-year-old Chinese children in Hong Kong. On the Coloured Progressive Matrices these children obtained a mean IQ of 116. Samples from Australia, Czechoslovakia, Germany, Romania, the UK and the US obtain IQs in the range 95–102. It is suggested that these results pose difficulties for the environmentalist explanations commonly advanced to explain the low mean IQs obtained by some ethnic minorities in the United States.

scholarly journals Relative Roles of Circumnavigating Waves and Extratropics on the MJO and Its Relationship with the Mean State*

2013 ◽  
Vol 70 (3) ◽  
pp. 876-893 ◽  
Author(s):  
Pallav Ray ◽  
Tim Li
Keyword(s):  
Annual Cycle ◽  
General Circulation ◽  
Phase Relationship ◽  
Moisture Convergence ◽  
Prognostic Variables ◽  
Sensitivity Experiment ◽  
Budget Analysis ◽  
Change In The Mean ◽  
The Mean ◽  
Mean State

Abstract A set of atmospheric general circulation model (GCM) experiments is designed to explore the relative roles of the circumnavigating waves and the extratropics on the Madden–Julian oscillation (MJO). In a “control” simulation, the model is forced by the climatological monthly sea surface temperature for 20 yr. In the first sensitivity experiment, model prognostic variables are relaxed in the tropical Atlantic region (20°S–20°N, 80°W–0°) toward the “controlled” climatological annual cycle to suppress the influences from the circumnavigating waves. In the second sensitivity experiment, model prognostic variables are relaxed in the 20°–30° latitude zones toward the controlled climatological annual cycle to suppress the influences from the extratropics (or the tropics–extratropics interactions). The numerical results demonstrate that the extratropics play a more important role in maintaining the MJO variance than the circumnavigating waves. The simulations further show that both the tropical mean precipitation and the intraseasonal precipitation variability are reduced when the extratropical influences are suppressed. The in-phase relationship is primarily attributed to the effect of the mean state on perturbations. A moisture budget analysis indicates that a positive feedback to the mean precipitation by the anomalous moisture convergence is offset by a negative feedback due to the anomalous moisture advection. The change in the mean precipitation in the absence of extratropical influences is primarily determined by the change in the mean moisture convergence, which in turn is due to the change in circulation. This study is the first attempt to quantitatively separate the effects of the circumnavigating waves and the extratropics on the MJO. Implications and limitations of this study are discussed.

Diagnosing Northern Hemisphere Jet Portrayal in 17 CMIP3 Global Climate Models: Twentieth-Century Intermodel Variability

2013 ◽  
Vol 26 (14) ◽  
pp. 4910-4929 ◽  
Author(s):  
Sharon C. Delcambre ◽  
David J. Lorenz ◽  
Daniel J. Vimont ◽  
Jonathan E. Martin
Keyword(s):  
Twentieth Century ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Jet Stream ◽  
The Pacific ◽  
Ensemble Mean ◽  
The Mean ◽  
Upper Level ◽  
Mean State

Abstract The present study focuses on diagnosing the intermodel variability of nonzonally averaged NH winter jet stream portrayal in 17 global climate models (GCMs) from phase three of the Coupled Model Intercomparison Project (CMIP3). Relative to the reanalysis, the ensemble-mean 300-hPa Atlantic jet is too zonally extended and located too far equatorward in GCMs. The Pacific jet varies significantly between modeling groups, with large biases in the vicinity of the jet exit region that cancel in the ensemble mean. After seeking relationships between twentieth-century model wind biases and 1) the internal modes of jet variability or 2) tropical sea surface temperatures (SSTs), it is found that biases in upper-level winds are strongly related to an ENSO-like pattern in winter-mean tropical Pacific Ocean SST biases. The spatial structure of the leading modes of variability of the upper-level jet in the twentieth century is found to be accurately modeled in all 17 GCMs. Also, it is shown that Pacific model biases in the longitude of EOFs 1 and 2 are strongly linked to the modeled longitude of the Pacific jet exit, indicating that the improved characterization of the mean state of the Pacific jet may positively impact the modeled variability. This work suggests that improvements in model portrayal of the tropical Pacific mean state may significantly advance the portrayal of the mean state of the Pacific and Atlantic jets, which will consequently improve the modeled jet stream variability in the Pacific. To complement these findings, a companion paper examines the twenty-first-century GCM projections of the nonzonally averaged NH jet streams.

scholarly journals A 10–15-Yr Modulation Cycle of ENSO Intensity

2009 ◽  
Vol 22 (7) ◽  
pp. 1718-1735 ◽  
Author(s):  
Fengpeng Sun ◽  
Jin-Yi Yu
Keyword(s):  
El Niño ◽  
El Nino ◽  
Surface Wind ◽  
Tropical Pacific ◽  
La Niña ◽  
Central Pacific ◽  
La Nina ◽  
The Pacific ◽  
The Mean ◽  
Mean State

Abstract This study examines the slow modulation of El Niño–Southern Oscillation (ENSO) intensity and its underlying mechanism. A 10–15-yr ENSO intensity modulation cycle is identified from historical and paleoclimate data by calculating the envelope function of boreal winter Niño-3.4 and Niño-3 sea surface temperature (SST) indices. Composite analyses reveal interesting spatial asymmetries between El Niño and La Niña events within the modulation cycle. In the enhanced intensity periods of the cycle, El Niño is located in the eastern tropical Pacific and La Niña in the central tropical Pacific. The asymmetry is reversed in the weakened intensity periods: El Niño centers in the central Pacific and La Niña in the eastern Pacific. El Niño and La Niña centered in the eastern Pacific are accompanied with basin-scale surface wind and thermocline anomalies, whereas those centered in the central Pacific are accompanied with local wind and thermocline anomalies. The El Niño–La Niña asymmetries provide a possible mechanism for ENSO to exert a nonzero residual effect that could lead to slow changes in the Pacific mean state. The mean state changes are characterized by an SST dipole pattern between the eastern and central tropical Pacific, which appears as one leading EOF mode of tropical Pacific decadal variability. The Pacific Walker circulation migrates zonally in association with this decadal mode and also changes the mean surface wind and thermocline patterns along the equator. Although the causality has not been established, it is speculated that the mean state changes in turn favor the alternative spatial patterns of El Niño and La Niña that manifest as the reversed ENSO asymmetries. Using these findings, an ENSO–Pacific climate interaction mechanism is hypothesized to explain the decadal ENSO intensity modulation cycle.

Genetic and Morphological Diversity in Aphis gossypii Glover (Hemiptera: Aphididae) in the Pacific Basin

2019 ◽  
Vol 73 (3) ◽  
pp. 367
Author(s):  
Ross H. Miller ◽  
Robert G. Foottit ◽  
Eric Maw ◽  
Keith S. Pike
Keyword(s):  
Aphis Gossypii ◽  
Morphological Diversity ◽  
Pacific Basin ◽  
The Pacific ◽  
Aphis Gossypii Glover

Supplemental material: Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

2006 ◽  
Author(s):  
J.K. Madsen ◽  
D.J. Thorkelson ◽  
R.M. Friedman ◽  
D.D. Marshall
Keyword(s):  
North America ◽  
Pacific Basin ◽  
Western North America ◽  
File Size ◽  
Tectonic Model ◽  
Ridge Subduction ◽  
The Pacific ◽  
Northwestern North America ◽  
Slab Window

Geosphere, February 2006, v. 2, p. 11-34, doi: 10.1130/GES00020.1. Movie 1 - Tectonic model for the Pacific Basin and northwestern North America from 53 Ma to 39 Ma. The file size is 1.3 MB.

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