This comprehensive text and reference work on numerical weather prediction, first published in 2002, covers not only methods for numerical modeling, but also the important related areas of data assimilation and predictability. It incorporates all aspects of environmental computer modeling including an historical overview of the subject, equations of motion and their approximations, a modern and clear description of numerical methods, and the determination of initial conditions using weather observations (an important science known as data assimilation). Finally, this book provides a clear discussion of the problems of predictability and chaos in dynamical systems and how they can be applied to atmospheric and oceanic systems. Professors and students in meteorology, atmospheric science, oceanography, hydrology and environmental science will find much to interest them in this book, which can also form the basis of one or more graduate-level courses.

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Atmospheric Modeling, Data Assimilation and Predictability

(2005). Atmospheric Modeling, Data Assimilation, and Predictability. Technometrics: Vol. 47, No. 4, pp. 521-521.

Atmospheric Modeling, Data Assimilation, and Predictability

The three-dimensional Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) has been developed by the Naval Research Laboratory COAMPS consists of an atmospheric data assimilation system comprising data quality control, analysis, initialization, and nonhydrostatic forecast model components, as well as a hydrostatic ocean model The models can be integrated simultaneously so that the surface fluxes of heat, momentum, and moisture are exchanged across the air–water interface every time step Optionally, either the atmospheric or ocean model can be used as a stand-alone system The atmospheric component of COAMPS was used for operational support for the America3 team in the 1995 America’s Cup races Results of these forecasts indicated the necessity of data assimilation to reduce model spinup in the first 6 h of the forecast Accurate forecasts of the low-level wind in the coastal race area was accomplished by utilizing triply nested grids to attain the necessary high resolution to resolve 

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The Naval Research Laboratory’s Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS)

The Meso-NH Atmospheric Simulation Sys- tem is a joint eAort of the Centre National de Recher- ches Meteorologiques and Laboratoire d'Aerologie. It comprises several elements; a numerical model able to simulate the atmospheric motions, ranging from the large meso-alpha scale down to the micro-scale, with a comprehensive physical package, a flexible file manager, an ensemble of facilities to prepare initial states, either idealized or interpolated from meteorological analyses or forecasts, a flexible post-processing and graphical facility to visualize the results, and an ensemble of interactive procedures to control these functions. Some of the distinctive features of this ensemble are the following: the model is currently based on the Lipps and Hemler form of the anelastic system, but may evolve towards a more accurate form of the equations system. In the future, it will allow for simultaneous simulation of several scales of motion, by the so-called ''interactive grid-nesting technique''. It allows for the in-line com- putation and accumulation of various terms of the budget of several quantities. It allows for the transport and diAusion of passive scalars, to be coupled with a chemical module. It uses the relatively new Fortran 90 compiler. It is tailored to be easily implemented on any UNIX machine. Meso-NH is designed as a research tool for small and meso-scale atmospheric processes. It is freely accessible to the research community, and we have tried to make it as ''user-friendly'' as possible, and as general as possible, although these two goals sometimes appear contradictory. The present paper presents a general description of the adiabatic formulation and some of the basic validation simulations. A list of the currently available physical parametrizations and ini- tialization methods is also given. A more precise description of these aspects will be provided in a further paper.

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The Meso-NH Atmospheric Simulation System. Part I: adiabatic formulation and control simulations

¶The nonhydrostatic model LM was developed for small scale operational predictions. Advances in computer development will give the possibility of operational models of a rather fine scale, which will cover the meso-gamma scale. The LM is currently applied at a scale of 7 km and an increase of the operational resolution to 2.5 km is planned for the next few years. Predictions of such high resolution require to abandon the hydrostatic assumption, which is used with most current operational weather prediction models. The LM was designed to cover all resolutions from 50 m to 50 km with an efficiency making it suitable for operational use. It is a fully elastic model, using second order centred finite differences. The time integration is done using the Klemp–Wilhelmson method, treating the slow modes by a larger time step than the fast modes. The vertical propagation of the fast waves is done implicitly. After describing the design of the LM, this paper gives examples of model predictions at the meso-γ scale. Some results of the current operational application at the resolution 7 km are presented. Deficiencies in the localisation of model generated precipitation are investigated using an idealised bell shaped mountain and applying different resolutions. In this way the convergence to the correct solution can be investigated. From these results it is concluded, that orographic filtering is necessary and the effect of such filtering on precipitation forecasts is investigated. Finally, the prediction of a squall line over northern Germany is shown in order to demonstrate the potential of the model in forecasting the meso-γ scale.

Meso-gamma scale forecasts using the nonhydrostatic model LM

On the use of a coordinate transformation for the solution of the Navier-Stokes equations

Numerical solution of the navier-stokes equations with topography

A three-dimensional numerical cloud model has been used to test a method for retrieving temperature and pressure deviation fields from detailed wind and water fields in deep convective clouds. A comparison of the retrieved fields with the output from the numerical model was used to test the validity of the theoretical treatment and accuracy of the programming. The local time derivatives of each of the velocity components are known to be potential problem sources in using Doppler radar data, and a test was done with this derivative estimated over a 4 min time span rather than 30 s, resulting in excellent agreement with the original solution for this data set. When the local derivative was eliminated, the solution was judged useful for general temperature patterns. Errors due to the inability to measure cloudwater mixing ratio and inaccuracies in rainwater mixing ratio were found to be significant, but not so severe as in the turbulence and steady-state sensitivity tests.

Retrieval of Thermodynamic Variables within Deep Convective Clouds: Experiments in Three Dimensions

Pressure, buoyancy and virtual potential temperature perturbations are calculated from wind fields derived from Doppler radar data taken in a surface cold front. The dynamics of the front are similar to a density current This hypothesis is also suggested by accompanying numerical simulations of cold air outflows. The updraft at the leading edge of the cold air mass is maintained in conjunction with an upward directed pressure force. The average maximum updraft is in excess of 7 m s−1 without any appreciable potential instability present in the “undisturbed” warm-sector sounding. The buoyancy and virtual potential temperature data reveal a front with a substantial fraction of the cooling taking place within the first 2 km of a frontal zone. Thus, the aspect ratio (width/depth) of the front, even after the filtering associated with the interpolation and retrieval process, is slightly less than one. The frontogenesis for the shear in the along-front wind and the thermal gradient are discussed. The g...

A Severe Frontal Rainband. Part III: Derived Thermodynamic Structure

Droplet pairs collision efficiencies and coalescence parameters, computing flow fields from nonlinear time dependent Navier-Stokes equations

Tzvi Gal-Chen

Papers

On the use of a coordinate transformation for the solution of the Navier-Stokes equations

Numerical solution of the navier-stokes equations with topography

Retrieval of Thermodynamic Variables within Deep Convective Clouds: Experiments in Three Dimensions

A Severe Frontal Rainband. Part III: Derived Thermodynamic Structure

A Numerical Study of Collision Efficiencies and Coalescence Parameters for Droplet Pairs with Radii up to 300 Microns