General circulation of the atmosphere

Abstract

latitude direct cells.This basic view of the general circulation of the atmosphere has not changed during the last 4 yr. However, during this time there has been a considerable increase in our understanding of the processes involved, through a combination of observational studies, theoretical studies, numerical simulation experiments, and laboratory experiments. In particular, there have been extensive compilations of observed data yielding better general circulation statistics, many theoretical investigations of nonlinear processes in planetary fluid dynamics, and continued development of comprehensive general circulation models and their extensive use for simulation experiments.Many important topics are not fully covered here, but are being treated by other reviewers as, for example, tropical disturbances, polar meteorology, planetary boundary layer, air-sea interaction, long-term climate changes and climate modeling, upper atmosphere, and numerical weather prediction. OBSERVATIONAL STUDIES Mean values, variances, and transports. Oort and Rasrnusson [1971] have derived extensive zonally averaged monthly statistics of the northern hemisphere general circulation, using as their principal data set the 'Massachusetts Institute of Technology (MIT) General Circulation Data Library,' which consists of daily aerological observations for the 5-yr period from May 1958 through April 1963, mainly from northern hemisphere stations, collected and processed by the Traveler's Research Center for V. P. Starr of Massachusetts Institute of Technology. The zonally averaged mean values, variances, and meridional transports of the wind components, temperature, geopotential, and specific humidity are presented for each month as a function of latitude between 10øS and 75øN and of height between the earth's surface and 50 mbar. The vertical transports by the stationary eddies and by the mean meridional circulation are also given. In separate papers, Oort and Rasrnusson [1970], Oort [1971] and Rasrnusson [1972] discuss the annual variations of the mean meridional circulation, the meridional energy transport, and the meridional water vapor transport in detail. Newell and his associates have extended the studies by Kidson et at. [1969] and Newell et at. [1970] in a twovolume book [Newell et at., 1972, 1974a] which contains extensive compilations of seasonal statistics of the tropical and extratropical general circulation. The data from virtually all radiosonde and radar wind stations between 45øS and 35øN for the period from July 1957 through December 1964 were included in the compilation. For latitudes between 45øS and 45øN and levels between the earth's surface and 100 mbar the book presents seasonal mean values of wind components and temperature, variances of wind components, and meridional transports of momentum and heat in terms of local values at each longitude as well as their zonal averages. The book also contains chapters on the monthly statistics of tropical humidity parameters [Rasrnusson, 1972], distributions of radiative heat...

Role of Microphysics and Convective Autoconversion for the Better Simulation of Tropical Intraseasonal Oscillations (MISO and MJO)

“…One of the major challenges in CGCMs for the simulation of MJO as well as ISO is the poor representation of cloud processes in the parameterization scheme (Hazra, Chaudhari, Saha, & Pokhrel, 2017; Hazra, Chaudhari, Saha, Pokhrel, & Goswami, 2017; Lee et al., 2003; Maloney, 2002; Maloney & Hartmann, 2001). This is because they are convectively coupled phenomena and cloud feedback plays an important role in those processes (Arakawa 1975, 2004; Frank, 1983; Randall et al., 2003). The biases in the mean rainfall structure in the Indian Ocean (Sperber & Annamalai, 2008) and unrealistic Ocean‐atmospheric coupling (Hendon, 2000; Waliser et al., 1999) are also responsible in this connection.…”