Atmospheric GCM Response to Extratropical SST Anomalies: Synthesis and Evaluation*

Kushnir, Yochanan; Robinson, Walter A.; Bladé, Ileana; Hall, Nicholas M. J.; Peng, Shiling; Sutton, Rowan

doi:10.1175/1520-0442(2002)015<2233:agrtes>2.0.co;2

Cited by 581 publications

(614 citation statements)

References 110 publications

(174 reference statements)

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“…This suggests a pathway via which SST anomalies may influence the development of synoptic systems: SST anomalies influence thickness anomalies, which in turn alters thickness gradients, thermal wind, and the potential for systems to develop. Similar relationships based on SST's and their gradients have been articulated in observational (Kushnir et al, 2002) and modeling studies (Frederiksen and Balgovind, 1994;Kushnir et al, 2002;Ummenhofer et al, 2008).…”

Section: Enso/iod Classificationsupporting

confidence: 59%

Characteristics and variability of synoptic features associated with cool season rainfall in southeastern Australia

Risbey

Pook

McIntosh

et al. 2008

Intl Journal of Climatology

140

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Cool season rainfall variability in southeastern Australia is investigated via classification and characterization of the predominant types of synoptic systems occurring in the region. These types are frontal systems, cut-off low systems, and other systems. Rainfall in the region is dominated by cut-off systems and these systems are the main influence on the interannual variability of rainfall. Both cut-off systems and frontal systems display an enhancement of thermal (thickness) gradient as rainfall increases, but the mechanisms for intensification differ. Cut-off systems intensify in the region in association with local increases in baroclinicity and the subtropical jet, whereas frontal systems tend to intensify via a confluence of subtropical and polar jets. Interannual rainfall variability is examined for groupings of years based on both clustering of continental rainfall patterns and on El Nino/Southern Oscillation (ENSO)/Indian Ocean Dipole (IOD) years. Cut-off systems exhibit consistent enhancements of thermal gradients for groupings of years in which they produce more rainfall. For ENSO/IOD groupings, the cut-off thermal gradients are consistent with the underlying sea surface temperature (SST) anomalies. Wet years in southeastern Australia are usually produced by cut-off systems, but can also be produced by frontal systems. In those cases the mid-tropospheric flow pattern is reminiscent of the negative Southern Annular Mode (SAM) pattern. The positive SAM pattern is also associated with enhanced rainfall in the southeast via local intensification of blocking and cut-off systems.

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Section: Enso/iod Classificationsupporting

confidence: 59%

Characteristics and variability of synoptic features associated with cool season rainfall in southeastern Australia

Risbey

Pook

McIntosh

et al. 2008

Intl Journal of Climatology

140

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“…The opposite is true for positive SSTA. This is one of the salient features of observed extratropical SSTA and their associated atmospheric patterns, as described in Frankignoul [1985] and Kushnir et al [2002].…”

Section: Horizontal Structure Of the Air-sea System During Wwr And Nomentioning

confidence: 62%

“…Overall, the SSTA shows continuous decreases (increases) in the positive (negative) non-WWR years without WWR (Figure 2c and 2d). Thus, the differences between 1951, 1956, 1965, 1966, 1968, 1971, 1974Negative 1959, 1960, 1977, 1978, 1983, 1985, 1986, 1994, 1996, 1998, 1999Non-WWR Positive 1950, 1952, 1953, 1954, 1955, 1957, 1962, 1963, 1967, 1969, 1972, 1976, 1982, 1989, 1990, 1991, 1993, 2000, 2002Negative 1958, 1961, 1964, 1970, 1973, 1975, 1979, 1980, 1981, 1984, 1987, 1988, 1992, 1995, 2001…”

Section: Methodsologymentioning

confidence: 99%

“…Alexander and Deser [1995] examined this hypothesis in greater detail and termed it the reemergence mechanism. Subsequent studies have shown that this reemergence mechanism occurs across much of the North Pacific [Alexander et al, 1999;Kushnir et al, 2002;Deser et al, 2003]. In addition, other dynamic oceanic processes, such as advection, may impact the persistence of the mixed layer temperature anomalies in the North Pacific [Sugimoto and Hanawa, 2005].…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Winter‐to‐winter recurrence and non‐winter‐to‐winter recurrence of SST anomalies in the central North Pacific

Zhao¹,

Li²

2012

J. Geophys. Res.

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[1] All previous studies of the winter-to-winter recurrence (WWR) of sea surface temperature anomalies (SSTA) have focused on mean climatic characteristics. Here, interannual variability of the SSTA WWR in the central North Pacific (CNP) is studied. The SSTA WWR displays a strong interannual variability in the CNP. The relative roles of atmospheric forcing and the oceanic reemergence mechanism are investigated by comparing SSTA WWR years and non-WWR years. Oceanic reemergence mechanism operates every year, the SSTA in the following winter, however, depends not only on the oceanic entrainment but also the atmospheric forcing, which exhibits substantial interannual variability. During SSTA WWR years, atmospheric circulation anomalies also exhibit the WWR phenomenon. Atmospheric forcing as well as the oceanic reemergence mechanism can act synergistically to create SSTA in the following winter with the same sign. During SSTA non-WWR years, winter atmospheric circulation anomalies do not recur in the following winter, and the following winter has opposing atmospheric forcing on SSTA. Although the reemergence mechanism is likely still operating, the anomalous heating supplied by the oceanic reemergence mechanism is smaller than that coming through the atmospheric forcing. Overall, the WWR in the CNP is an evolutional characteristic of the whole air-sea system with the seasons, and the WWR of atmospheric circulation anomalies and its forcing play an important role in the SSTA WWR.Citation: Zhao, X., and J. Li (2012), Winter-to-winter recurrence and non-winter-to-winter recurrence of SST anomalies in the central North Pacific,

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“…A long-standing question has been the extent to which anomalous extra-tropical SSTs feed back to affect the atmosphere (e.g. Rodwell et al, 1999;Robinson, 2000;Kushnir et al, 2002). It has been shown that AGCMs forced with observed SST anomalies can reproduce the annular mode behaviour that induced these extra-tropical SST anomalies (Rodwell et al, 1999).…”

Section: Goga Model-data Comparisonmentioning

confidence: 99%

The global footprint of persistent extra‐tropical drought in the instrumental era

Herweijer

Seager

2008

Intl Journal of Climatology

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The major North American droughts as per instrumental records are shown to be part of a larger, global pattern of low‐frequency drought variability. Drought in western North America during the 1850s–1860s, 1870s, 1890s, 1930s and 1950s, is shown to coincide with the occurrence of prolonged dry spells in parts of Europe, southern South America and western Australia. Tropical land regions are mostly wet during these periods, with the exception of central east Africa, southern India and Sri Lanka, which are dry. The recent 1998–2003 period of drought in western North America reveals a similar global hydroclimatic ‘footprint’ with the exception of a wet southern South America and continued dry conditions in the Sahel. Common to each of the six droughts is the persistence of anomalously cool east central tropical Pacific sea surface temperatures (SSTs). For the 1998–2003 case, the warming of SSTs everywhere outside of the east central tropical Pacific may be influencing precipitation and masking the influence of persistent precipitation anomalies driven from the tropical Pacific alone. In general, examination of these major historical extra‐tropical droughts reveals a hemispherically and, in the extra‐tropics, a zonally symmetric pattern consistent with forcing from the Tropics.Ensembles of model simulations forced by observed SSTs globally (Global Ocean Global Atmosphere, GOGA) and only within the tropical Pacific (Pacific Ocean Global Atmosphere‐Mixed Layer, POGA‐ML) are both able to capture the global pattern of the persistent extra‐tropical drought regimes since the mid‐nineteenth century. This implies that the recently demonstrated link between SST forcing and drought in North America is in fact only one part of a global hydroclimatic response to the persistence of cool SST anomalies in the tropical Pacific. Indian Ocean SST forcing is required to capture the droughts in central east Africa. Over Europe, the modelled, low‐frequency precipitation signal is unrealistically ENSO dominated, as the model does not faithfully reproduce the observed history of low‐frequency NAO variability. Overall, our results suggest that the global pattern of persistent drought appears to be a low‐frequency version of interannual ENSO‐forced variability. Copyright © 2008 Royal Meteorological Society

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Atmospheric GCM Response to Extratropical SST Anomalies: Synthesis and Evaluation*

Cited by 581 publications

References 110 publications

Characteristics and variability of synoptic features associated with cool season rainfall in southeastern Australia

Characteristics and variability of synoptic features associated with cool season rainfall in southeastern Australia

Winter‐to‐winter recurrence and non‐winter‐to‐winter recurrence of SST anomalies in the central North Pacific

The global footprint of persistent extra‐tropical drought in the instrumental era

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