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1 edition of The sensitivity of ageostrophic circulations to model resolution found in the catalog.

The sensitivity of ageostrophic circulations to model resolution

James Berdeguez

The sensitivity of ageostrophic circulations to model resolution

a case study using NGM forecasts of ERICA IOP-4

by James Berdeguez

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Published by Naval Postgraduate School, Available from the National Technical Information Service in Monterey, Calif, Springfield, Va .
Written in English


Edition Notes

ContributionsPauley, Patricia M.
The Physical Object
Pagination138 p. ;
Number of Pages138
ID Numbers
Open LibraryOL25507250M

submesoscale density fronts and ageostrophic circulations about them in the weakly stratified surface boundary layer. Here the high-resolution simulations are further analyzed from the per-spective of the kinetic energy (KE) spectrum shape and spectral energy fluxes in the mesoscale-to-submesoscale range in the upper ocean. A diagnostic analysis is made for the ageostrophic secondary circulation, buoyancy flux and frontogenetic tendency (SCFT) in upper-ocean submesoscale fronts and dense filaments under the combined influences of boundary-layer turbulent mixing, surface wind stress and surface gravity waves. The low-over-high version is a good model of a jet streak, which is discussed in Chapter 6 of the book(see Figs. , and ). As can be seen from the figures above, the high-over-low version is a good model for blocking, and this subject is explored in Matlab problem M, which uses the QG model and diagnostic package that come with.   As demonstrated in Fig. 3, between 30° S and 60° S the model-derived zonally averaged EKE differs from the altimetry-derived zonally averaged EKE by a factor of on is a reasonable match compared to coarser resolution eddy-permitting models used to study heat transport. For example, Jayne and Marotzke reported that EKE in 1/4° resolution Parallel Ocean Climate Model .

  The sensitivity analysis is based on 11 values per parameter, linearly increasing between minimum and maximum values, for a total of model runs per analysis. The wind-jumps range between m s −1, and initial ABL depth from m (rural) and m (urban).


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The sensitivity of ageostrophic circulations to model resolution by James Berdeguez Download PDF EPUB FB2

Calhoun: The NPS Institutional Archive Theses and Dissertations Thesis Collection The sensitivity of ageostrophic circulations to model resolution: a case study using NGM forecasts of. The Sensitivity of Ageostrophic Circulations to Model Resolution: A Case Study Using NGM Forecasts of ERICA IOP-4 by James Berdeguez Lieutenant, United States Navy B.S., United States Naval Academy, Submitted in partial fulfillment of the requirements The sensitivity of ageostrophic circulations to model resolution book the degree of MASTER OF SCIENCE IN METEOROLOGY AND PHYSICAL OCEANOGRAPHY from theAuthor: James Berdeguez.

Approved for public release; distribution is unlimitedThe effect of model resolution on the ageostrohic circulations and dynamics of a rapidly deepening extratropical cyclone that occurred during the Intensive Observing Period (IOP) 4 ( January ) of the Experiment on Rapidly Intensifying Cyclones over the Atlantic (ERICA) is examined using the psi-vector technique proposed by Keyser, et al.

().Author: James Berdeguez. Finally, the presence of the forcing D dr means that the ageostrophic circulations in the MABL are not stationary and this result was confirmed by an analysis of the convective clouds evolution performed from the Meteosat and Advanced Very High Resolution Radiometer satellital images (Lambert et al.

).Cited by: AVHRR pixels are gathered to obtain temperature retrieval at the resolution of our global model of ref-erence: Action de Recherche Petite Echelle Grande Echelle (ARPEGE), 30 ϫ 30 km 2 in the area.

General Circulation Models (GCMs) are rapidly assuming widespread use as powerful tools for predicting global events on time scales of months to decades, such as the onset of EL Nino, monsoons, soil moisture saturation indices, global warming estimates, and even snowfall predictions.

While GCMs have been praised for helping to foretell the current El Nino and its impact on droughts in. Jiang and Raymond () studied both balanced and unbalanced circulations in a mature mesoscale convective system by using a nonlinear balance model.

As a complement to their work, the present study uses the semigeostrophic system, which retains ageostrophic advection and a vector vorticity equation, to provide additional dynamical insights.

1. Introduction. Most diagnostic studies based on data from quasi-synoptic oceanographic surveys are undertaken in the framework of quasi-geostrophic (Q-G) dynamics (e.g., Tintoré et al., ; Pollard and Regier, ; Allen et al., ).A main reason is that, within this framework, not only geostrophic fields but also some features of the ageostrophic circulation can be diagnosed from.

The generalized formulation of the Omega equation 1 allows to diagnose the impact of the various dynamical terms from model data or direct in situ measurements that include both the 3‐D density and full horizontal velocity fields (namely both the geostrophic and the ageostrophic components).

Conversely, it cannot be used to estimate the. Section 3 The sensitivity of ageostrophic circulations to model resolution book all the high-resolution cases considered for different mixing parameterizations and surface forcing, and Section 4 summarizes the results.

Method Physical model. The equations of the SG frontal model used in this study are identical to those presented by Nagai et al. The results again show that the eddy convergence term is the most important ageostrophic term, and can be as important as the geostrophic effect.

The mean vorticity equation budget shows a similar sensitivity to the horizontal resolution and zero heat capacity atmospheric model. As predicted by the Ekman transport calculation, the ageostrophic current direction deviates by 90 ° clockwise to the wind direction. This is not the case for the geostrophic component.

The intensity of the ageostrophic current ranges from 25% to 50% of the total current. A three-dimensional ocean model has been utilized to study circulation and its seasonal variation in the South China Sea (SCS) in response to the forcing of the Asian monsoon and the Kuroshio intrusion.

The SCS ocean model has a resolution of approximately 10 km horizontal spacing and 30 vertical levels with a realistic bottom topography.

Formulations for the ageostrophic winds have included calculating this quantity as a residual, which then is dependent upon how geostrophy itself is defined (e.g., Phillips ; Blackburn ).Various alternative formulations for ageostrophic motions relating ageostrophic circulations to geostrophy have also been used in the examination of the three-dimensional circulations associated.

The trend in operational numerical weather prediction (NWP) since the implementation of the six-layer primitive equation model (Shuman and Hovermale ) has been toward improving horizontal resolution and the attendant modelthe forecast component of the National Centers for Environmental Prediction (NCEP, formerly NMC) Regional Analysis and Forecast System (RAFS.

The ageostrophic wind is an essential component of the synoptic-scale and mesoscale atmospheric environments, yet is often overlooked. A review of the. underlying theory is presented, along with a. This could initiate the release of CSI or accentuate slantwise ageostrophic circulations.

sensitivity to the initial configuration of the disturbances, especially their position relative to the baroclinic jet axis, will be analyzed. Impact of surface properties and model resolution, Quarterly Journal of the Royal Meteorological Society.

Provides a comprehensive view of the role of clouds and water vapor in helping control the past, present, and future large-scale circulations, with impacts on climate sensitivity Includes thorough assessments of current understanding and future opportunities enabled by field experiments, new and prospective technologies, and emerging synthesis.

A three-dimensional ocean model has been utilized to study circulation and its seasonal variation in the South China Sea (SCS) in response to the forcing of the Asian monsoon and the Kuroshio intrusion. The SCS ocean model has a resolution of approximately 10 km horizontal spacing and 30 vertical levels with a realistic bottom topography.

The model is forced with time-dependent wind stress and. The primary dataset used in this study is a collection of aircraft dropsonde profiles of which met our criteria from 24 flight transects through 15 different ARs obtained during intensive observing periods (IOPs) conducted in the northeastern Pacific over a 5-yr period ().These IOPs and their aircraft include the NOAA G-IV for CalWater –15 and two Cs from the U.S.

Air Force. Sensitivity of Tropical Cyclone Formation to Resolution‐Dependent and Independent Tracking Schemes in High‐Resolution Climate Model Simulations. tracking schemes in the reanalysis data and in a high‐resolution climate model with interannually varying sea surface temperatures.

detects the circulations that have the potential for TC. ageostrophic circulations is a cross-front Ekman advection of density, leading to a destabilization of 99 the water column, frontal intensification, and subduction on the dense side of the front. The sensitivity to the model grid resolution is surprisingly minor.

Considerable differences between the individual stations suggest that local surface conditions such as roughness length, albedo or soil moisture may play an important role in the observed mismatch between model simulations and observations. However, the contribution to the total current of its ageostrophic component forced by the surface winds is significant, with a correlation coefficient varying from to Ó Elsevier Ltd.

In this paper, the mechanism and model-representation of a late-spring severe blizzard event on eastern Romania are studied.

The mechanism relies on the coupled contribution of the tropospheric ageostrophic circulations associated to jet streaks. These circulations: (1) interact under local and regional forcing (sea surface temperature, topography and latent heat) and (2) feedback on enhancing.

The F Ronts 87 project was a European experiment to make mesoscale observations to deduce the dynamics of active cold fronts approaching north‐west Europe, with a minimum of orographic influences. In this paper data from dropsoundings made by the Meteorological Office's C‐ research aircraft are analysed.

The aircraft flew a pattern with 4 or 5 runs oriented approximately at right angles. high vertical resolution of about m in the lower troposphere is required to obtain well-formed slantwise circulations near the cloud head and to make the distinction between cold-conveyor-belt jet and sting jet.

In contrast, when the surface cyclone is initialized on. Frontal circulations in the presence of small viscous moist symmetric stability and weak forcing. Sensitivity to potential vorticity, Mesoscale ageostrophic circulations of two fronts observed during the fronts87 experiment: Diagnosis and interpretation, Meteorology and Atmospheric Physics, /BF configuration of a high-resolution mesoscale numerical model.

The initial setup ageostrophic circulations. Most of our knowledge on sting jets is based on observations or section 3 concerns the sensitivity to the initial configurat ion of the synoptic disturbances.

Finally, section 4. An analysis of the Richardson number is used to evaluate the change in instability as a result of the ageostrophic circulations. The Richardson number prior to the deep mixing event is given by Ri = N 2 /(S 2 /f) 2.

The perturbation of b and u g due to ageostrophic circulations (denoted by b a and u a) are given as (from Eqs. The northwestern Mediterranean Sea (NWM hereafter – Fig. 1b) is a key location for studying intense air–sea exchanges.

Both coastal and offshore ocean processes contribute significantly to the circulation in the GoL area, which is characterized by a continental shelf ending with a very steep slope and several submarine canyons (Fig.

1b).The Mistral and Tramontane, which are generally. Humphrey W. Lean, Peter A. Clark, The effects of changing resolution on mesocale modelling of line convection and slantwise circulations in FASTEX IOP16, Quarterly Journal of the Royal Meteorological Society, /qj, (), ().

Extreme precipitation and flood episodes in the Himalayas are oftentimes traced to synoptic situations involving connections between equatorward advancing upper level extratropical circulations and moisture-laden tropical monsoon circulation. While previous studies have documented precipitation characteristics in the Himalayan region during severe storm cases, a comprehensive.

The study concerns the anelastic nonhydrostatic model EULAG as a prospective candidate for the new dynamical core of a high-resolution NWP model. Such an application requires a series of benchmark.

ageostrophic secondary circulations (ASCs) on the three-dimensional (3-D) dispersal of dissolved cesium (Cs) released from the Fukushima Daiichi Nuclear Power Plant (FNPP1). Extensive model-data com-parison demonstrated that the innermost high-resolution model, with a lateral grid resolution of 1 km.

The resolution of the model was set to km in latitude/longitude, with 23 levels along the vertical in addition to six levels in the boundary layer. The MABL model used is the medium range forecast model (MRF [Hong and Pan, ]), which was used in MM5 for many years. Introduction. The boundary current along the coast of the Catalano-Balearic (CB) Sea (Fig 1) constitutes a part of the Western Mediterranean cyclonic circulation flows southward along the topographic slope zone with a maximum speed of approximately ms-1 within the upper m layer along the main jet axis, decreasing gradually to ms-1 at m to result in a total downstream.

In particular, model resolution has increased (in winter the ECMWF system has horizontal resolution T which corresponds to about 16 km grid) and precipitation forecast improved (e.g. Andersson et al. A better description of IG circulations on the mesoscale, in the middle atmosphere and in the.

Regional downscaling has proven useful in adding details to the global solution. However, the parameterized physical processes can systematically deviate the large‐scale features in.

The ROMS configuration consists of triple-nested model domains with an off-line, one-way nesting technique that downscales from 5 km horizontal resolution for the U.

West Coast (L0), to 1 km resolution for the SCB (L1), to m horizontal resolution. This study estimated the sensitivity of rainfall characteristics (rainfall amount, rainfall frequency, rainfall intensity, and rainfall extremes based on min intervals) to land-surface conditions over Southeast Asia, which has a wet land surface during the rainy season.

To obtain the regional difference in sensitivity and simulate basic cloud-precipitation systems, we used a high-resolution.The MESO-NH Atmospheric Model Atmospheric simulations were performed with the non-hydrostatic mesoscale MESO-NH model (13).

The same model configuration as in Lebeaupin et al. () is used with two interactive nested grids running at horizontal resolution of km and km respectively (Figure 1), centered over the mesoscale system with.The intrusions were largely density compensated but their position corresponded to a narrow filament of intense cyclonic vorticity at the surface.

We showed that the intrusions were generated by the wind-stress that intensified the ageostrophic circulations at the large-scale frontogenetic front by driving a cross-front Ekman buoyancy flux.