Tropical-Extratropical Geopotential Height Teleconnections during the Northern Hemisphere Winter

Mo, Kingtse C.; Livezey, Robert E.

doi:10.1175/1520-0493(1986)114<2488:teghtd>2.0.co;2

Cited by 209 publications

(149 citation statements)

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“…In the Northern Hemisphere extratropics, anomalous cyclonic circulations coincide with the regions of negative sensitivity over central Asia, the north Pacific, United States, and the north Atlantic. The north Pacific and United States circulations agree well with ENSOassociated upper-troposphere height anomalies observed by Mo and Livezey (1986) and Trenberth et al (1998). Similar cyclonic circulations aligned with negative sensitivity in the Southern Hemisphere are seen over the southern Pacific Ocean and over the southern tip of South America.…”

Section: Changes In Advectionsupporting

confidence: 75%

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

2016

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Abstract. We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Niño Southern Oscillation (ENSO) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Niño 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9-year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes.

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Section: Changes In Advectionsupporting

confidence: 75%

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

2016

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“…[22] The principal patterns of atmospheric circulation variability have been analyzed and described in numerous studies [Rogers and Van Loon, 1979;Wallace and Gutzler, 1981;Mo and Livezey, 1986;Barnston and Livezey, 1987]. These atmospheric circulation patterns affect the climate of large areas of the Northern Hemisphere [e.g., Trenberth, 1990;Zorita et al, 1992;Hurrell, 1995;Hurrell and Van Loon, 1997;Gershunov and Barnett, 1998].…”

Section: Atmospheric Circulation Patterns In the Northern Hemispherementioning

confidence: 99%

Role of atmospheric circulation with respect to the interannual variability in the date of snow cover disappearance over northern latitudes between 1988 and 2003

Vicente‐Serrano¹,

Grippa²,

Toan³

et al. 2007

J. Geophys. Res.

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[1] This paper analyzes the main spatial patterns in the dates of snow cover disappearance variability over northern latitudes between 1988 and 2003. The dates of snow cover disappearance were calculated using satellite passive microwave data from the Special Sensor Microwave/Imager. Spatial and temporal patterns were obtained using principal components analysis in the S mode. We identified eight components, each representing a large region characterized by homogeneous interannual variability in the dates of snow cover disappearance. We found that atmospheric circulation, summarized by means of teleconnection indices, had an important impact on the date of snow cover disappearance for most of these regions. A role is played by the Arctic Oscillation in western Siberia, the spring east Atlantic/west Russian pattern in central Siberia, and the Pacific North American pattern in southern Canada, while the El Niño-Southern Oscillation phenomenon and the west Pacific pattern are significantly related to variability in the date of snow cover disappearance in the northernmost areas of America. For the regions where we found no relationship between the interannual variability in the date of snow cover disappearance and the teleconnection indices, a direct relationship with some spatial patterns of sea level pressures, which are not well summarized by the teleconnection indices, was found.

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“…Two modes having large impact on the circulation and rainfall anomalies over North America are the Pacific-North American (PNA) mode (Wallace and Giutzler, 1981) and the Tropical Northern Hemisphere (NH) mode (Mo and Livezey, 1986;Barnston and Livezey, 1987). They are represented by wave trains extending from the tropical Pacific into North America.…”

Section: Introductionmentioning

confidence: 99%

The Pacific–South American modes and their downstream effects

Paegle

2001

Intl Journal of Climatology

Self Cite

327

228

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There are two pervasive modes of atmospheric variability in the Southern Hemisphere (SH) that influence circulation and rainfall anomalies over South America. They appear as leading empirical orthogonal functions (EOFs) of 500-hPa height or 200-hPa streamfunction anomalies and are found from intraseasonal to decadal time scales. Both patterns exhibit wave 3 hemispheric patterns in mid to high latitudes, and a well-defined wave train with large amplitude in the Pacific-South American (PSA) sector. Therefore, they are referred to as the PSA modes (PSA1 and PSA2).PSA1 is related to sea surface temperature anomalies (SSTAs) over the central and eastern Pacific at decadal scales, and it is the response to El Niñ o-Southern Oscillation (ENSO) in the interannual band. The associated rainfall summer pattern shows rainfall deficits over northeastern Brazil and enhanced rainfall over southeastern South America similar to rainfall anomalies during ENSO. PSA2 is associated with the quasi-biennial component of ENSO, with a period of 22-28 months and the strongest connections occur during the austral spring. The associated rainfall pattern shows a dipole pattern with anomalies out of phase between the South Atlantic Convergence Zone (SACZ) extending from central South America into the Atlantic and the subtropical plains centred at 35°S.These two modes are also apparent in tropical intraseasonal oscillations for both summer and winter. Eastward propagation of enhanced convection from the Indian Ocean through the western Pacific to the central Pacific is accompanied by a wave train that appears to originate in the convective regions. The positive PSA1 pattern is associated with enhanced convection over the Pacific from 150°E to the date line. The convection pattern associated with PSA2 is in quadrature with that of PSA1. Both PSA modes are influenced by the Madden Julian Oscillation and influence rainfall over South America.

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Tropical-Extratropical Geopotential Height Teleconnections during the Northern Hemisphere Winter

Cited by 209 publications

References 0 publications

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

Role of atmospheric circulation with respect to the interannual variability in the date of snow cover disappearance over northern latitudes between 1988 and 2003

The Pacific–South American modes and their downstream effects

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