Zeng Qingcun

Simultaneous non-linear retrieval of atmospheric temperature and absorbing constituent profiles from satellite infrared sounder radiances

Based on Zengs theory (1974), a successive linearized form of radiative transfer equation (RTE) is derived for simultaneous retrieval of atmospheric temperature and absorbing constituent profiles from satellite infrared observations. It contains the temperature component weighting function and absorbing constituent (H2O, O3, CH4 etc.) component weighting functions. All these weighting functions reach maximum at their own “optimum information levels”, and make the remote sensing equations well-conditional. Then the atmospheric profiles are derived by Newtons non-linear iteration method. Experiments of retrieval from both TIROS-N operational High Resolution Infrared Sounder (HIRS) and the simulated Atmospheric InfRared Sounder (AIRS) show an significant improvement.

Evolution of large scale disturbances and their interaction with mean flow in a rotating barotropic atmosphere—Part II

The problems on evolution of large-scale disturbances and their interaction with mean flow recently attract much effort of meteorologists due to their practical importance in weather and limate predictions. In this paper, some theoretical results obtained in current investigations of these problems will be reviewed. A barotropic atmosphere is taken in this paper, and the baroclinic atmosphere is left in our second paper.The following aspects are reviewed: First, the general properties of two-dimensional barotropic motion both in the nonlinear and linearized equations and both in the quasi-geostrophic and non-geostrophic models. Second, the evolution and the structure of Rossby wave packet superimposed on a zonal or nonzonal basic flow.In this part, only the above two problems are reviewed. The remanent problems, i.e., the normal modes and continuous spectra of both quasi-geostrophic and non-geostrophic models, weakly nonlinear theory and the fully nonlinear theory will be discussed in part II (another paper).

Criteria for the nonlinear stability of three—dimensional quasi—geostrophic motions

Some more proper criteria for the nonlinear stability of three–dimensional quasi–geostrophic motions are given by combining variational principle with a prior estimates method. The criteria are suitable for perturbations of initial condition as well as parameters in the model. The basic flow can be steady or unsteady. Particularly the difficulty due to the nonlinear boundary condition is completely overcome by the use of our method.

Nonlinear baroclinic haurwitz waves

A family of nonlinear wave solutions, with Haurwitz waves as their zero-order approximations, to the baroclinic primitive equations is derived and the corresponding calculating system is presented. Numerical experiments with a two-level global model developed by ourselves confirm the validity of the theoretical results to a great extent.A family of nonlinear wave solutions, with Haurwitz waves as their zero-order approximations, to the baroclinic primitive equations is derived and the corresponding calculating system is presented. Numerical experiments with a two-level global model developed by ourselves confirm the validity of the theoretical results to a great extent.

On the generation and maintenance of atmospheric disturbances

Blocking is one of the intensive atmospheric disturbances which can maintain for a long time. In this paprer we investigate the general conditions favorable for the generation and maintenance of the intensive disturbances. First, the evolutional process of disturbances superimposed on a jet-like zonal flow is studied by using the wave-packet representation and the WKBJ method. Second, the mechanism for generation and maintenance of disturbances is investigated by using the nonlinear equations and the general physical laws. Finally, some numerical experiments are given for illustration, showing the rapid absorption of disturbances by the jet-like zonal flow in one case and the maintenance of disturbances for a long time in the other case.

Numerical simulation of the Mindanao Eddy and Tropical Currents of Pacific Ocean

Results of numerical simulation of currents in the western North Tropical Pacific Ocean by using a barotropic primitive equation model with fine horizontal resolution agreed well with observations and showed that the Mindanao Cyclonic Eddy located north of the equator and east of Mindanao Island exists during most of the year with monthly (and large seasonal) variations in scope, strength and central location. In June, an anticyclonic eddy occurs northeast of Halmahera Island, strength-circulation systems such as the North Equatorial Current, the Mindanao Current and the North Equatorial Countercurrent are all very well reproduced in the simulations.

The propagation of inertia-gravity waves and their influence on zonal mean flow part two: Wave breaking and critical levels

The gravity wave breaking is crucial to the large-scale circulation of middle atmosphere. In this paper, we follow Lindzen (1981) to draw out the parameterization of two-dimensional gravity wave breaking including inertial effect. Also we present some properties of critical levels and inertial critical levels.

The advances in the studies on general circulation and large-scale dynamics, and their prospects for the year of 2000

In this paper, we review the progress made in the studies on general circulation and large-scale dynamics. We divide the advances in the studies on the atmospheric circulation and large-scale dynamics into 4 stages, i.e., the studies on atmospheric wave dynamics; the studies on the observational facts of general circulation; the numerical studies on general circulation; and the studies on planetary wave dynamics, wave-mean flow interaction and nonlinear dynamics. Moreover, the prospects of the studies on the atmospheric circulation and large-scale dynamics for the future are also made in this paper.In this paper, we review the progress made in the studies on general circulation and large-scale dynamics. We divide the advances in the studies on the atmospheric circulation and large-scale dynamics into 4 stages, i.e., the studies on atmospheric wave dynamics; the studies on the observational facts of general circulation; the numerical studies on general circulation; and the studies on planetary wave dynamics, wave-mean flow interaction and nonlinear dynamics. Moreover, the prospects of the studies on the atmospheric circulation and large-scale dynamics for the future are also made in this paper.