Barotropic Primitive Equation Model Research Articles

A Variable-Resolution Finite-Element Technique for Regional Forecasting with the Primitive Equations

A barotropic primitive-equation model using the finite-element method of space discretization is generalized to allow variable resolution. The overhead incurred in going from a uniform mesh to a variable mesh having the same number of degrees of freedom is found to be approximately 20% overall. The variable-mesh model is used with several grid configurations, each having uniform high resolution over a specified area of interest and lower resolution elsewhere to produce short-term forecasts over this area without the necessity of high resolution everywhere. It is found that the forecast produced on a uniform high-resolution mesh can be essentially reproduced for a limited time over the limited area by a variable-mesh model having only a fraction of the number of degrees of freedom and requiring significantly less computer time. As expected, the period of validity of forecasts on variable meshes can be lengthened by refining the mesh in the outer region. It is concluded that from the point of view of efficiency, accuracy and stability the variable-mesh finite-element technique appears to be well-suited to the practical problem of limited area/time forecasting.

Numerical experiment with primitive equation barotropic model using quasi-Lagrangian advection scheme to predict the movement of monsoon depression and tropical cyclone

A limited-area primitive equation barotropic model using quasi-Lagrangian advection scheme has been integrated upto 48 hours with wind as input to predict the movement of a monsoon depression and a tropical cyclone in the Indian region. The vector error in the forecast of the centre of the monsoon depression is 55 km in 24 hr and 220 km in 48 hr. The cortesponding errors in the case of the tropical cyclone are 0 km and 80 km respectively. Verification statistics for the predicted u and v fields are presented and discussed.

On the application of a primitive equation barotropic Model for the prediction of storm tracks In the Indian region

Methods of prediction of storm tracks in the Arabian Sea and the Bay of Bengal by the use of a limited area primitive equation barotropic model have been discussed with case-studies, They are (i) the total flow direct integration method. {ii) the point vortex method in which the basic flow is separated from the disturbance and integrated, treating the vortex as a point and advecting the same at each time step by the basic field and (iii) the modified point vortex method in which the interaction of the disturbance flow with the basic flow is taken into account in the method in (ii).

A Semi-Implicit Finite-Element Barotropic Model

Abstract A barotropic primitive equation model using the finite-element method of space discretization is presented. The semi-implicit method of time discretization is implemented by taking a suitable form of the governing equations. Finite-element forecasts are then compared with those from both finite-difference and spectral models. From the point of view of both efficiency and accuracy it is concluded that the finite-element method of space discretization appears to he viable for the practical problem of numerical weather prediction.

Numerical experiments with a primitive equation barotropic model for the prediction of movement of monsoon depressions and tropical cyclones : SINGH S. S. and KSHUDIRAM SAHA, 1976 J. appl. Met., 15 (8): 805–810

Numerical experiments with a primitive equation barotropic model for the prediction of movement of monsoon depressions and tropical cyclones : SINGH S. S. and KSHUDIRAM SAHA, 1976 J. appl. Met., 15 (8): 805–810

Numerical Experiments with a Primitive Equation Barotropic Model for the Prediction of Movement of Monsoon Depressions and Tropical Cyclones

Abstract A limited-area primitive equation barotropic model with wind as input has been integrated up to 72 h to predict the movement of a monsoon depression and a tropical cyclone in the Indian region. The forecast up to 48 h is satisfactory in both cases whereas that beyond this period appears to deteriorate rapidly.

Application of a Primitive Equation Barotropic Model to Predict Movement of “Western Disturbances”

Abstract A primitive equation, limited-area, barotropic model with east-west cyclic boundary conditions is used to predict the movement of “Western Disturbances” in the Asian subtropics in two cases. Forecast and verification charts up to 72 hr and relevant error statistics are presented. Results are encouraging enough for the study of more such cases, and for the application of the model for low-latitude monsoon depressions and tropical cyclones.

DEVELOPMENT OF A LIMITED AREA FINE-MESH PREDICTION MODEL

A limited area, fine-mesh, primitive equation barotropic model has been integrated using data observed at 500 mb. The lateral boundary conditions used in the model required that no change occur on the boundary during the 24-hr forecast. The predictions compare favorably with those obtained with the barotropic and baroclinic models in operational use at the National Meteorological Center.