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example, the released latent heat is one of the major sources driving the atmospheric general circulation as well as the circulation within the tropics (e.g., Ramage 1968 ; Chang and Lau 1982 ), and the Rossby wave trains that emanate from the convection distort atmospheric flow patterns at higher latitudes (e.g., Stan et al. 2017 ; Yang et al. 2019 ). Numerous field experiments have been conducted that have greatly improved understanding of the convective activity and associated circulations over
example, the released latent heat is one of the major sources driving the atmospheric general circulation as well as the circulation within the tropics (e.g., Ramage 1968 ; Chang and Lau 1982 ), and the Rossby wave trains that emanate from the convection distort atmospheric flow patterns at higher latitudes (e.g., Stan et al. 2017 ; Yang et al. 2019 ). Numerous field experiments have been conducted that have greatly improved understanding of the convective activity and associated circulations over
justifies the use of υyQ 0 as a reasonable approximation for the moisture meridional advection υ Q ¯ y . It also gives the meridional moisture advection term the same form as the Coriolis term under the equatorial β -plane approximation, and allows Eq. (4) to preserve its symmetry about the equator in all terms. b. Reduction to a second-order ODE for υ We assume plane wave solutions proportional to exp[ i ( kx − ωt )] for u , υ , ϕ , and q , where k is the nondimensional planetary
justifies the use of υyQ 0 as a reasonable approximation for the moisture meridional advection υ Q ¯ y . It also gives the meridional moisture advection term the same form as the Coriolis term under the equatorial β -plane approximation, and allows Eq. (4) to preserve its symmetry about the equator in all terms. b. Reduction to a second-order ODE for υ We assume plane wave solutions proportional to exp[ i ( kx − ωt )] for u , υ , ϕ , and q , where k is the nondimensional planetary
passage of the MJO. They partitioned the heating into convective, stratiform, and radiative components, and found that with the onset of the MJO, the stratiform rainfall anomalies lagged the convective anomalies by a few days. In most numerical weather or climate models, the diabatic heating is calculated as an explicit potential temperature tendency. Depending on the formulation of the model, the heating will arise from the microphysics scheme, the cumulus scheme, the planetary boundary layer scheme
passage of the MJO. They partitioned the heating into convective, stratiform, and radiative components, and found that with the onset of the MJO, the stratiform rainfall anomalies lagged the convective anomalies by a few days. In most numerical weather or climate models, the diabatic heating is calculated as an explicit potential temperature tendency. Depending on the formulation of the model, the heating will arise from the microphysics scheme, the cumulus scheme, the planetary boundary layer scheme
the NESC have not been adequately explored so far. The seasonal variability of the Pacific equatorial subsurface currents has been studied by Lukas and Firing (1985) , Kessler and McCreary (1993) , and Marin et al. (2010) , showing that the annual reversal of the Equatorial Intermediate Current is controlled by vertical propagation of baroclinic Rossby waves. Using Argo parking depth trajectory measurements, Cravatte et al. (2012) showed that the largely one cycle per year variations of the
the NESC have not been adequately explored so far. The seasonal variability of the Pacific equatorial subsurface currents has been studied by Lukas and Firing (1985) , Kessler and McCreary (1993) , and Marin et al. (2010) , showing that the annual reversal of the Equatorial Intermediate Current is controlled by vertical propagation of baroclinic Rossby waves. Using Argo parking depth trajectory measurements, Cravatte et al. (2012) showed that the largely one cycle per year variations of the
, we chose MT instead of pure MRG waves ( Matsuno 1966 ) in this study. Table 1. The range of planetary zonal wavenumber, period, and equivalent depth chosen for filtering waves and their corresponding reference. Positive (negative) planetary zonal wavenumber indicates eastward (westward) propagation. MJO and MT do not follow the dispersion curve so the equivalent depths are not calculated. c. Diurnal cycle analysis To analyze the diurnal variation of precipitation, the dates are separated into
, we chose MT instead of pure MRG waves ( Matsuno 1966 ) in this study. Table 1. The range of planetary zonal wavenumber, period, and equivalent depth chosen for filtering waves and their corresponding reference. Positive (negative) planetary zonal wavenumber indicates eastward (westward) propagation. MJO and MT do not follow the dispersion curve so the equivalent depths are not calculated. c. Diurnal cycle analysis To analyze the diurnal variation of precipitation, the dates are separated into
1. Introduction The Madden–Julian oscillation (MJO) is the dominant intraseasonal variability in the tropical atmosphere. It can be described as a tropical planetary-scale circulation system coupled with a multiscale convective complex and propagating eastward slowly with a rearward tilted vertical structure and a mixed Kelvin–Rossby wave horizontal structure ( Madden and Julian 1972 ; Wheeler and Kiladis 1999 ; Wheeler et al. 2000 ; Kiladis et al. 2005 ; Wang 2012 ). The planetary
1. Introduction The Madden–Julian oscillation (MJO) is the dominant intraseasonal variability in the tropical atmosphere. It can be described as a tropical planetary-scale circulation system coupled with a multiscale convective complex and propagating eastward slowly with a rearward tilted vertical structure and a mixed Kelvin–Rossby wave horizontal structure ( Madden and Julian 1972 ; Wheeler and Kiladis 1999 ; Wheeler et al. 2000 ; Kiladis et al. 2005 ; Wang 2012 ). The planetary
, S.-K. Yang , J. J. Hnilo , M. Fiorino , and G. L. Potter , 2002 : NCEP–DOE AMIP-II Reanalysis (R-2) . Bull. Amer. Meteor. Soc. , 83 , 1631 – 1644 , https://doi.org/10.1175/BAMS-83-11-1631 . 10.1175/BAMS-83-11-1631 Kodera , K. , H. Mukougawa , and S. Itoh , 2008 : Tropospheric impact of reflected planetary waves from the stratosphere . Geophys. Res. Lett. , 35 , L16806 , https://doi.org/10.1029/2008GL034575 . 10.1029/2008GL034575 Lee , S. , T. Gong , N
, S.-K. Yang , J. J. Hnilo , M. Fiorino , and G. L. Potter , 2002 : NCEP–DOE AMIP-II Reanalysis (R-2) . Bull. Amer. Meteor. Soc. , 83 , 1631 – 1644 , https://doi.org/10.1175/BAMS-83-11-1631 . 10.1175/BAMS-83-11-1631 Kodera , K. , H. Mukougawa , and S. Itoh , 2008 : Tropospheric impact of reflected planetary waves from the stratosphere . Geophys. Res. Lett. , 35 , L16806 , https://doi.org/10.1029/2008GL034575 . 10.1029/2008GL034575 Lee , S. , T. Gong , N
characterized by a zonally planetary length scale with global wavenumber 1–2 ( Wang and Rui 1990 ; Li and Zhou 2009 ), a Kelvin wave and Rossby wave couplet pattern ( Rui and Wang 1990 ; Wang and Li 1994 ; Li and Wang 1994 ; Adames and Wallace 2014 ), and a vertically tilted structure in vertical velocity and moisture fields ( Sperber 2003 ; Hsu and Li 2012 ). Table 1. List of acronyms. Most MJO events initiate in the west Indian Ocean ( Matthews 2008 ; Zhao et al. 2013 ; Straub 2013 ), weaken over
characterized by a zonally planetary length scale with global wavenumber 1–2 ( Wang and Rui 1990 ; Li and Zhou 2009 ), a Kelvin wave and Rossby wave couplet pattern ( Rui and Wang 1990 ; Wang and Li 1994 ; Li and Wang 1994 ; Adames and Wallace 2014 ), and a vertically tilted structure in vertical velocity and moisture fields ( Sperber 2003 ; Hsu and Li 2012 ). Table 1. List of acronyms. Most MJO events initiate in the west Indian Ocean ( Matthews 2008 ; Zhao et al. 2013 ; Straub 2013 ), weaken over
baroclinic models to show extratropical responses to tropical heating as a Rossby wave train propagating out of the tropics in the upper troposphere (e.g., Hoskins and Karoly 1981 ; Jin and Hoskins 1995 ). Ferranti et al. (1990) studied tropical–extratropical interaction associated with the 30–60-day oscillation and its impact on medium- and extended-range prediction. The anomalous upper-tropospheric divergence associated with tropical heating acts as a Rossby wave source for poleward dispersing
baroclinic models to show extratropical responses to tropical heating as a Rossby wave train propagating out of the tropics in the upper troposphere (e.g., Hoskins and Karoly 1981 ; Jin and Hoskins 1995 ). Ferranti et al. (1990) studied tropical–extratropical interaction associated with the 30–60-day oscillation and its impact on medium- and extended-range prediction. The anomalous upper-tropospheric divergence associated with tropical heating acts as a Rossby wave source for poleward dispersing
1. Introduction The Madden–Julian oscillation (MJO) is the dominant planetary-scale convective structure and intraseasonal mode in the tropics ( Zhang et al. 2020 ). The MJO generally propagates eastward from the Indian Ocean to the central Pacific Ocean with a speed of ∼5 m s −1 , recurring at Earth’s equator every 30–90 days ( Xie et al. 1963 ; Madden and Julian 1971 , 1972 ; Li et al. 2018 ). The anomalous convection of the MJO as a diabatic heating source excites poleward
1. Introduction The Madden–Julian oscillation (MJO) is the dominant planetary-scale convective structure and intraseasonal mode in the tropics ( Zhang et al. 2020 ). The MJO generally propagates eastward from the Indian Ocean to the central Pacific Ocean with a speed of ∼5 m s −1 , recurring at Earth’s equator every 30–90 days ( Xie et al. 1963 ; Madden and Julian 1971 , 1972 ; Li et al. 2018 ). The anomalous convection of the MJO as a diabatic heating source excites poleward
