Journal ArticleDOI
Convectively Coupled Equatorial Waves: Analysis of Clouds and Temperature in the Wavenumber–Frequency Domain
Reads0
Chats0
TLDR
In this article, a wavenumber-frequency spectrum analysis is performed for all longitudes in the domain 158S−158N using a long (;18 years) twice-daily record of satellite-observed outgoing longwave radiation (OLR), a good proxy for deep tropical convection.Abstract:
A wavenumber-frequency spectrum analysis is performed for all longitudes in the domain 158S‐158N using a long (;18 years) twice-daily record of satellite-observed outgoing longwave radiation (OLR), a good proxy for deep tropical convection. The broad nature of the spectrum is red in both zonal wavenumber and frequency. By removing an estimated background spectrum, numerous statistically significant spectral peaks are isolated. Some of the peaks correspond quite well to the dispersion relations of the equatorially trapped wave modes of shallow water theory with implied equivalent depths in the range of 12‐50 m. Cross-spectrum analysis with the satellite-based microwave sounding unit deep-layer temperature data shows that these spectral peaks in the OLR are ‘‘coupled’’ with this dynamical field. The equivalent depths of the convectively coupled waves are shallower than those typical of equatorial waves uncoupled with convection. Such a small equivalent depth is thought to be a result of the interaction between convection and the dynamics. The convectively coupled equatorial waves identified correspond to the Kelvin, n 5 1 equatorial Rossby, mixed Rossby-gravity, n 5 0 eastward inertiogravity, n 5 1 westward inertio-gravity (WIG), and n 5 2 WIG waves. Additionally, the Madden‐Julian oscillation and tropical depression-type disturbances are present in the OLR spectra. These latter two features are unlike the convectively coupled equatorial waves due to their location away from the equatorial wave dispersion curves in the wavenumber-frequency domain. Extraction of the different convectively coupled disturbances in the time‐longitude domain is performed by filtering the OLR dataset for very specific zonal wavenumbers and frequencies. The geographical distribution of the variance of these filtered data gives further evidence that some of the spectral peaks correspond to particular equatorial wave modes. The results have implications for the cumulus parameterization problem, for the excitation of equatorial waves in the lower stratosphere, and for extended-range forecasting in the Tropics.read more
Citations
More filters
Journal ArticleDOI
Intraseasonal and Seasonally Persisting Patterns of Indian Monsoon Rainfall
V. Krishnamurthy,Jagadish Shukla +1 more
TL;DR: The space-time structure of the active and break periods of the Indian monsoon has been studied using 70-yr-long high-resolution gridded daily rainfall data over India as discussed by the authors.
Journal ArticleDOI
State of the Climate in 2015
Jessica Blunden,Derek S. Arndt +1 more
TL;DR: The State of the Climate for 2016 as discussed by the authors is a very low-resolution file and it can be downloaded in a few minutes for a high-resolution version of the report to download.
Journal ArticleDOI
LMDZ5B: the atmospheric component of the IPSL climate model with revisited parameterizations for clouds and convection
Frédéric Hourdin,Jean-Yves Grandpeix,Catherine Rio,Sandrine Bony,Arnaud Jam,Frédérique Cheruy,Nicolas Rochetin,Laurent Fairhead,Abderrahmane Idelkadi,Ionela Musat,Jean-Louis Dufresne,Alain Lahellec,Marie-Pierre Lefebvre,Romain Roehrig +13 more
TL;DR: In this paper, a new version of the LMDZ atmospheric general circulation model has been developed that corresponds to a complete recasting of the parameterization of turbulence, convection and clouds.
Journal ArticleDOI
Stratiform Precipitation, Vertical Heating Profiles, and the Madden Julian Oscillation
TL;DR: In this article, the observed profile of heating through the troposphere in the Madden-Julian oscillation (MJO) is found to be very top heavy: more so than seasonal-mean heating and systematically more than all of the seven models for which intraseasonal heating anomaly profiles have been published.
Journal ArticleDOI
An Idealized Semi-Empirical Framework for Modeling the Madden–Julian Oscillation
Adam H. Sobel,Eric D. Maloney +1 more
TL;DR: In this article, a simple semi-empirical model is presented to explore the hypothesis that the Madden-Julian oscillation can be represented as a moisture mode destabilized by surface flux and cloud-radiative feedbacks.
References
More filters
Journal ArticleDOI
The NCEP/NCAR 40-Year Reanalysis Project
Eugenia Kalnay,Masao Kanamitsu,Robert Kistler,William D. Collins,D.G. Deaven,L. S. Gandin,M. Iredell,Suranjana Saha,Glenn H. White,John S. Woollen,Yuejian Zhu,Muthuvel Chelliah,Wesley Ebisuzaki,Wayne Higgins,John E. Janowiak,Kingtse C. Mo,Chester F. Ropelewski,Julian X. L. Wang,Ants Leetmaa,Richard W. Reynolds,Roy L. Jenne,Dennis Joseph +21 more
TL;DR: The NCEP/NCAR 40-yr reanalysis uses a frozen state-of-the-art global data assimilation system and a database as complete as possible, except that the horizontal resolution is T62 (about 210 km) as discussed by the authors.
Journal ArticleDOI
Quasi-geostrophic motions in the equatorial area
TL;DR: In this article, a single layer of homogeneous incompressible fluid with free surface is treated, where the Coriolis parameter is assumed to be proportional to the latitude, and a strong east-west current was formed along the equator.
Journal ArticleDOI
Observations of the 40-50-day tropical oscillation - a review
Roland A. Madden,Paul R. Julian +1 more
TL;DR: The 40-50-day cyclone oscillation is the result of large-scale circulation cells oriented in the equatorial plane that move eastward from at least the Indian Ocean to the central Pacific as discussed by the authors.
Journal ArticleDOI
TOGA COARE: The Coupled Ocean-Atmosphere Response Experiment.
Peter J. Webster,Roger Lukas +1 more
TL;DR: In this article, the authors present a simulation of the western Pacific warm pool, the region of the warmest sea surface temperature in the open oceans, which coexists with the largest annual precipitation and latent heat release in the atmosphere.