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stratospheric extratropical wave breaking ( Holton et al. 1995 ) and perhaps in the strength of the Hadley circulation ( Plumb and Eluszkiewicz 1999 ). At intraseasonal time scales, there is increasing evidence that tropical tropopause temperature fluctuations are associated with Kelvin waves. Zhou and Holton (2002) found that the cooling of the cold-point tropopause in the tropics is associated with the Madden–Julian oscillation (MJO; Madden and Julian 1971 ), and they attributed this cooling to the
stratospheric extratropical wave breaking ( Holton et al. 1995 ) and perhaps in the strength of the Hadley circulation ( Plumb and Eluszkiewicz 1999 ). At intraseasonal time scales, there is increasing evidence that tropical tropopause temperature fluctuations are associated with Kelvin waves. Zhou and Holton (2002) found that the cooling of the cold-point tropopause in the tropics is associated with the Madden–Julian oscillation (MJO; Madden and Julian 1971 ), and they attributed this cooling to the
given the special name of the “Kelvin wave” because of many striking similarities to the coastally trapped waves analyzed by Lord Kelvin in the nineteenth century ( Thomson 1880 ). The Kelvin wave has enormous practical importance as reviewed in sources as diverse as Chapman and Lindzen (1970) , Majda (2003) , and Andrews et al. (1987) . Longuet-Higgins (1968) carried out a magisterial study of the Hough functions in general and the Kelvin wave in particular nearly 40 years ago. Even so, there
given the special name of the “Kelvin wave” because of many striking similarities to the coastally trapped waves analyzed by Lord Kelvin in the nineteenth century ( Thomson 1880 ). The Kelvin wave has enormous practical importance as reviewed in sources as diverse as Chapman and Lindzen (1970) , Majda (2003) , and Andrews et al. (1987) . Longuet-Higgins (1968) carried out a magisterial study of the Hough functions in general and the Kelvin wave in particular nearly 40 years ago. Even so, there
; Kawamura et al. 2001 ; Trenberth et al. 2002 ; Chou et al. 2003 ; Sakai and Kawamura 2009 ). ENSO theories emphasize the role of wave dynamics on the initiation of ENSO, which involves both oceanic and atmospheric Kelvin waves and equatorial Rossby waves. On the other hand, ENSO-related changes in the ambient flow and thermal forcing would have an impact on equatorial waves in the atmosphere since a number of observational studies have shown that the zonal flow and convective forcing significantly
; Kawamura et al. 2001 ; Trenberth et al. 2002 ; Chou et al. 2003 ; Sakai and Kawamura 2009 ). ENSO theories emphasize the role of wave dynamics on the initiation of ENSO, which involves both oceanic and atmospheric Kelvin waves and equatorial Rossby waves. On the other hand, ENSO-related changes in the ambient flow and thermal forcing would have an impact on equatorial waves in the atmosphere since a number of observational studies have shown that the zonal flow and convective forcing significantly
1994 ; Pires et al. 1997 ; Wheeler and Kiladis 1999 , hereafter WK99 ; Wheeler et al. 2000 , hereafter WKW00 ). For instance, Straub and Kiladis (2002 , 2003 , hereafter SK02 and SK03 ) show that Kelvin waves are primary modulators of convective activity within the Pacific ITCZ, and that their structures resemble theoretical Kelvin waves. These equatorially trapped waves organize mesoscale convective elements into larger-scale structures within the Tropics, and as such they might
1994 ; Pires et al. 1997 ; Wheeler and Kiladis 1999 , hereafter WK99 ; Wheeler et al. 2000 , hereafter WKW00 ). For instance, Straub and Kiladis (2002 , 2003 , hereafter SK02 and SK03 ) show that Kelvin waves are primary modulators of convective activity within the Pacific ITCZ, and that their structures resemble theoretical Kelvin waves. These equatorially trapped waves organize mesoscale convective elements into larger-scale structures within the Tropics, and as such they might
1. Introduction Convectively coupled atmospheric Kelvin waves (hereafter “Kelvin waves”) form a substantial part of the subscale anatomy of the Madden–Julian oscillation (MJO; Zhang 2005 ; Madden and Julian 1994 ). The MJO modulates the background state of the atmosphere through which Kelvin waves travel, thereby allowing it to influence their structures and propagation. Within the local active convective phase of the MJO (hereafter just “active MJO”), Kelvin waves tend to propagate more
1. Introduction Convectively coupled atmospheric Kelvin waves (hereafter “Kelvin waves”) form a substantial part of the subscale anatomy of the Madden–Julian oscillation (MJO; Zhang 2005 ; Madden and Julian 1994 ). The MJO modulates the background state of the atmosphere through which Kelvin waves travel, thereby allowing it to influence their structures and propagation. Within the local active convective phase of the MJO (hereafter just “active MJO”), Kelvin waves tend to propagate more
1. Introduction The Kelvin wave is one of the fundamental waves in geophysical fluid dynamics and is involved in many atmospheric and oceanic phenomena on the Earth ( LeBlond and Mysak 1978 ; Gill 1982 ; Holton 2004 ). The Kelvin wave is a type of gravity wave and is formed by the interaction of Earth’s rotation and a lateral boundary. In the ocean, Kelvin waves are trapped against the coastline or the equator and propagate along these boundaries. Because the Southern Ocean has no meridional
1. Introduction The Kelvin wave is one of the fundamental waves in geophysical fluid dynamics and is involved in many atmospheric and oceanic phenomena on the Earth ( LeBlond and Mysak 1978 ; Gill 1982 ; Holton 2004 ). The Kelvin wave is a type of gravity wave and is formed by the interaction of Earth’s rotation and a lateral boundary. In the ocean, Kelvin waves are trapped against the coastline or the equator and propagate along these boundaries. Because the Southern Ocean has no meridional
1. Introduction A substantial fraction of the synoptic-scale convective variability in the tropics is associated with equatorial atmospheric disturbances (e.g., Takayabu 1994 ; Wheeler and Kiladis 1999 ; Wheeler et al. 2000 ; Kiladis et al. 2009 and references therein). The structure of these equatorial waves was predicted by the linear equatorial beta-plane shallow water theory of Matsuno (1966) . One of these equatorially trapped waves is the Kelvin wave and observations show that it is
1. Introduction A substantial fraction of the synoptic-scale convective variability in the tropics is associated with equatorial atmospheric disturbances (e.g., Takayabu 1994 ; Wheeler and Kiladis 1999 ; Wheeler et al. 2000 ; Kiladis et al. 2009 and references therein). The structure of these equatorial waves was predicted by the linear equatorial beta-plane shallow water theory of Matsuno (1966) . One of these equatorially trapped waves is the Kelvin wave and observations show that it is
1. Introduction a. Background Oceanic Kelvin waves are a dominant mode of variability in the equatorial Pacific ( Knox and Halpern 1982 ; Johnson and McPhaden 1993 ; Cravatte et al. 2003 ). The apparent relationships between the Madden–Julian oscillation (MJO; Madden and Julian 1994 ; Zhang 2001 ), oceanic Kelvin waves, and the El Niño–Southern Oscillation (ENSO) have been the subjects of much recent debate (e.g., Zhang and Gottschalck 2002 ). Each of these processes are characterized by
1. Introduction a. Background Oceanic Kelvin waves are a dominant mode of variability in the equatorial Pacific ( Knox and Halpern 1982 ; Johnson and McPhaden 1993 ; Cravatte et al. 2003 ). The apparent relationships between the Madden–Julian oscillation (MJO; Madden and Julian 1994 ; Zhang 2001 ), oceanic Kelvin waves, and the El Niño–Southern Oscillation (ENSO) have been the subjects of much recent debate (e.g., Zhang and Gottschalck 2002 ). Each of these processes are characterized by
1. Introduction A significant part of the synoptic-scale convective variability in the tropics is associated with equatorially trapped waves (e.g., Wheeler and Kiladis 1999 , hereafter WK99 ). This includes Kelvin waves that are treated theoretically by Matsuno (1966) and confirmed by observational studies (e.g., Takayabu 1994 ; WK99 ). This study is concerned with investigating the nature and variability of convectively coupled Kelvin waves that impact convection and rainfall over
1. Introduction A significant part of the synoptic-scale convective variability in the tropics is associated with equatorially trapped waves (e.g., Wheeler and Kiladis 1999 , hereafter WK99 ). This includes Kelvin waves that are treated theoretically by Matsuno (1966) and confirmed by observational studies (e.g., Takayabu 1994 ; WK99 ). This study is concerned with investigating the nature and variability of convectively coupled Kelvin waves that impact convection and rainfall over
, and references therein)]. The eastward propagating Kelvin wave is special in that the meridional wave velocity vanishes identically. For nonzero meridional velocity, there exists an infinite number of equatorial waves with trapping scales of the same order as that for the Kelvin waves, that is, the Rossby radius of deformation ( Matsuno 1966 ; Blandford 1966 ; Munk and Moore 1968 ). The main focus of the present study is the mean drift induced by internal equatorial Kelvin waves. Such waves
, and references therein)]. The eastward propagating Kelvin wave is special in that the meridional wave velocity vanishes identically. For nonzero meridional velocity, there exists an infinite number of equatorial waves with trapping scales of the same order as that for the Kelvin waves, that is, the Rossby radius of deformation ( Matsuno 1966 ; Blandford 1966 ; Munk and Moore 1968 ). The main focus of the present study is the mean drift induced by internal equatorial Kelvin waves. Such waves
