On the Adjustment Toward Balance in Primitive Equation Weather Prediction Models

Økland, Hans

doi:10.1175/1520-0493(1970)098<0271:otatbi>2.3.co;2

Cited by 17 publications

(5 citation statements)

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“…As verified by more complex theories and by numerical experiments with non-linear models (0kland, 1970;Anthes, 1974;Hoke and Anthes, 1976;Hoke and Anthes, 1977), the above results are surprisingly general, applying to a two-dimensional barotropic atmosphere and to stably stratified baroclinic atmospheres. For the latter, the results apply if L R = c g If where cg is the phase speed of internal gravity waves…”

Section: Adjustment Of Models To Cosmic Mass Field Data As Predicted supporting

confidence: 59%

Applications of COSMIC to Meteorology and Climate

Anthes¹,

Rocken²,

Kuo³

2000

Terr. Atmos. Ocean. Sci.

178

111

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Section: Adjustment Of Models To Cosmic Mass Field Data As Predicted supporting

confidence: 59%

Applications of COSMIC to Meteorology and Climate

Anthes¹,

Rocken²,

Kuo³

2000

Terr. Atmos. Ocean. Sci.

178

111

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“…Vector wind errors appear to increase at the same rate as virtual temperature errors decrease (Figs. 23 and 24), possibly due in part to mass-field dominance in the model adjustment process on the mesoscale in response to shallow modes forced by surface heating/cooling errors (e.g., Okland 1970;Stauffer and Seaman 1990). Of the four time periods investigated above, one compares a cold start with continuation times of less than 24 h after the cold start and the other three compare cold starts with continuation times of greater than 24 h. In all three of the cases where the continuation run is evaluated at times greater than 24 h after its cold start, the reinitialization showed, on average, better statistical skill than the continuation, even despite the detrimental effects of model spinup associated with the global model initialization in the reinitialization runs.…”

Section: ) Rrnps Accuracy Versus Length Of Nowcast Sequencementioning

confidence: 99%

An Automated High-Resolution, Rapidly Relocatable Meteorological Nowcasting and Prediction System

Schroeder

Stauffer

Seaman

et al. 2006

Monthly Weather Review

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An automated, rapidly relocatable nowcasting and prediction system, whose cornerstone is the fullphysics, nested-grid, nonhydrostatic fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5), has been under development at the Pennsylvania State University since the late 1990s. In the applications presented in this paper, the Rapidly Relocatable Nowcast-Prediction System (RRNPS) provides a continuous stream of highly detailed nowcasts, defined here as gridded meteorological fields produced by a high-resolution mesoscale model assimilating available observations and staying just ahead of the clock to provide immediately available current meteorological conditions. The RRNPS, configured to use 36-, 12-, and 4-km nested domains, is applied over the Great Plains for 18 case days in August 2001, over the East Coast region for 8 case days in April 2002, and for 12 case days during the winter and summer of 2003. The performance of the RRNPS is evaluated using subjective and statistical methods for runs with and without the use of continuous fourdimensional data assimilation (FDDA). A statistical evaluation of the dependence of RRNPS skill on the length of model integration yields further insight into the value added by FDDA in RRNPS nowcasts. It must be emphasized that unlike typical operational analysis systems, none of the current data are used in the nowcasts since the nowcasts are made available just ahead of the clock for immediate use. Because none of the verification data are assimilated into the RRNPS at the time of verification, this evaluation is a true test of the time-integrated effects of previous FDDA on current model solutions. Furthermore, the statistical evaluations also utilize independent data completely withheld from the system at all times.Evaluation of the RRNPS versus observations on the 4-and 12-km grids shows that there is little difference in statistical skill between the two resolutions for the two application regions. However, subjective case evaluations indicate that mesoscale detail is added to the wind and mass fields on the 4-km domain of the RRNPS as compared to the coarser 12-km domain. Statistics suggest that 4-km resolution provides slightly more accurate meteorology for the domain including complex terrain and coastlines. The statistics also show that the use of continuous FDDA in a high-resolution mesoscale model improves the accuracy of the RRNPS nowcasts, and that this unique nowcast prediction system provides immediately available forecast-analysis products that are comparable or superior to those produced at operational centers, especially for the surface and the boundary layer. Finally, the RRNPS is also designed to run locally and on demand in a highly automated mode on modest computing platforms (e.g., a dual-processor PC) with potentially very limited data resources and nonstandard data communications.

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“…Vol. 49, Special Issue (Washington, 1964 ;0kland, 1970). The faster the phase speed, the longer the critical wavelength.…”

Section: Discussionmentioning

confidence: 99%

“…The adjustment procedure in the model atmosphere does, however, emphasize the role of external inertio-gravitational waves the phase speed of which is several hundred meters per second, a nd hence the velocity field usually takes the initiative in change, with the mass field close..; ly following it, until balance is attained between them. (Washington, 1964, Nitta, 1969, 0kland, 1970 As far as external gravity waves are allowed to exist in the model atmospher e with the scale height, say 10 km, the situation may be unchanged. Gambo (personal communication) conducted a simple numerical experiment with an incompressible homogeneous fluid with rotation, and confirmed that for a reduced scale height the initiative of mutual adj ustment changed from the velocity to the mass field.…”

Section: Introductionmentioning

confidence: 99%

Response of a Dynamical Model to Partially Produced Imbalance in Meteorological Fields

Nitta

1971

Journal of the Meteorological Society of Japan

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Starting from a set of meteorological data, the response of a dynamical model to the artificially produced imbalance in the mass field is pursued by making use of the pseudo-forecast initialization procedure. A three-level primitive equation model in the a-coordinate system is used as the computational model. The imbalance is produced over a subdomain located near the center of the whole region as follows: Case A : The surface pressure is replaced within the sub domain by its area average over the same subdomain. Case B: The same as case A, but for the geopotential height at the middle level of the troposphere. Case C: A constant value (i.e., 5°C) is added to the temperature field at the lowest level. Case D: The same constant value is added to the temperature fields at all the information levels. As the wind field, the geostrophic wind is used, which is estimated from the geopotential height with the variable Coriolis parameter. During the iterative calculation mutual adjustment toward the quasi-geostrophic equilibrium is expected to take place between the mass and velocity fields. For the imbalance extending throughout the total air column (cases A and D), the recovery of the pattern from the unbalanced state to the original one was rapid and sufficient. The result may be explained by the essential role of the external inertiogravitational wave in the adjustment procedure. When it is deep, the imbalance is rapidly dissolved by the external mode because of the fast phase speed of the high frequency wave. The a djustment is then mostly performed under the initiative of the velocity field. Thus the restoration to the original pattern is sufficient. On the other hand, for the imbalance located within the air column (cases Band C), ffie convergence to the original was slow and worse than in the previous cases. In the latter cases, the internal mode of the gravity-inertia wave played the main role. Thus the adjustment procedure was dull, and initiative was given neither to the mass field nor to the wind field to yield a different state of balance from the original. Although the implications of the present experiment are limited, the result may be applicable to the processing of asynoptic data in weather analysis and may account for the influence of erroneous meteorological information upon numerical prediction.

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On the Adjustment Toward Balance in Primitive Equation Weather Prediction Models

Cited by 17 publications

References 0 publications

Applications of COSMIC to Meteorology and Climate

Applications of COSMIC to Meteorology and Climate

An Automated High-Resolution, Rapidly Relocatable Meteorological Nowcasting and Prediction System

Response of a Dynamical Model to Partially Produced Imbalance in Meteorological Fields

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