Toward Convective-Scale Prediction within the Next Generation Global Prediction System

AbstractThe Geophysical Fluid Dynamics Laboratory (GFDL) has developed a new variable-resolution global model with the ability to represent convective-scale features that serves as a prototype of the Next Generation Global Prediction System (NGGPS). The goal of this prediction system is to maintain the skill in large-scale features while simultaneously improving the prediction skill of convectively driven mesoscale phenomena. This paper demonstrates the new capability of this model in convective-scale prediction relative to the current operational Global Forecast System (GFS). This model uses the stretched-grid functionality of the Finite-Volume Cubed-Sphere Dynamical Core (FV3) to refine the global 13-km uniform-resolution model down to 4-km convection-permitting resolution over the contiguous United States (CONUS), and implements the GFDL single-moment 6-category cloud microphysics to improve the representation of moist processes. Statistics gathered from two years of simulations by the GFS and select configurations of the FV3-based model are carefully examined. The variable-resolution FV3-based model is shown to possess global forecast skill comparable with that of the operational GFS while quantitatively improving skill and better representing the diurnal cycle within the high-resolution area compared to the uniform mesh simulations. Forecasts of the occurrence of extreme precipitation rates over the southern Great Plains are also shown to improve with the variable-resolution model. Case studies are provided of a squall line and a hurricane to demonstrate the effectiveness of the variable-resolution model to simulate convective-scale phenomena.

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Evaluation of Tropical Cyclone Forecasts in the Next Generation Global Prediction System

Monthly Weather Review ◽

10.1175/mwr-d-18-0227.1 ◽

2019 ◽

Vol 147 (9) ◽

pp. 3409-3428 ◽

Cited By ~ 6

Author(s):

Jan-Huey Chen ◽

Shian-Jiann Lin ◽

Linjiong Zhou ◽

Xi Chen ◽

Shannon Rees ◽

...

Keyword(s):

Tropical Cyclone ◽

False Alarm ◽

Cloud Microphysics ◽

Lead Times ◽

Prediction System ◽

Next Generation ◽

Microphysics Scheme ◽

Great Opportunity ◽

Dynamical Core ◽

Intensity Prediction

Abstract A new global model using the GFDL nonhydrostatic Finite-Volume Cubed-Sphere Dynamical Core (FV3) coupled to physical parameterizations from the National Centers for Environmental Prediction’s Global Forecast System (NCEP/GFS) was built at GFDL, named fvGFS. The modern dynamical core, FV3, has been selected for the National Oceanic and Atmospheric Administration’s Next Generation Global Prediction System (NGGPS) due to its accuracy, adaptability, and computational efficiency, which brings a great opportunity for the unification of weather and climate prediction systems. The performance of tropical cyclone (TC) forecasts in the 13-km fvGFS is evaluated globally based on 363 daily cases of 10-day forecasts in 2015. Track and intensity errors of TCs in fvGFS are compared to those in the operational GFS. The fvGFS outperforms the GFS in TC intensity prediction for all basins. For TC track prediction, the fvGFS forecasts are substantially better over the northern Atlantic basin and the northern Pacific Ocean than the GFS forecasts. An updated version of the fvGFS with the GFDL 6-category cloud microphysics scheme is also investigated based on the same 363 cases. With this upgraded microphysics scheme, fvGFS shows much improvement in TC intensity prediction over the operational GFS. Besides track and intensity forecasts, the performance of TC genesis forecast is also compared between the fvGFS and operational GFS. In addition to evaluating the hit/false alarm ratios, a novel method is developed to investigate the lengths of TC genesis lead times in the forecasts. Both versions of fvGFS show higher hit ratios, lower false alarm ratios, and longer genesis lead times than those of the GFS model in most of the TC basins.

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Level of Detail and Multi-Resolution Modeling Techniques for Virtual Design and Prototyping

10.1115/imece1999-0154 ◽

1999 ◽

Author(s):

Zhigeng Pan ◽

Kun Zhou ◽

Chiyi Cheng ◽

Mingmin Zhang

Keyword(s):

Virtual Reality ◽

Large Scale ◽

Level Of Detail ◽

Data Sets ◽

Virtual Design ◽

Variable Resolution ◽

Modeling Techniques ◽

Resolution Model ◽

Cad Models ◽

Representation Scheme

Abstract Reconciling scene realism with interactivity has emerged as one of the most important areas in making virtual reality feasible for large-scale CAD data sets consisting of several millions of primitives. Level of detail (LoD) and multi-resolution modeling techniques in virtual reality can be used to speedup the process of virtual design and virtual prototyping. In this paper we present an automatic LoD generation and rendering algorithm which is suitable for CAD models and propose a new multi-resolution representation scheme called MRM (multi-resolution model), which can support efficient extraction of fixed resolution and variable resolution for multiple objects in the same scene. MRM scheme supports unified selective simplifications and selective refinements over the mesh. Furthermore, LoD and multi-resolution models may be used to support real-time geometric transmission in collaborative virtual design and prototyping.

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Operational Convective-Scale Numerical Weather Prediction with the COSMO Model: Description and Sensitivities

Monthly Weather Review ◽

10.1175/mwr-d-10-05013.1 ◽

2011 ◽

Vol 139 (12) ◽

pp. 3887-3905 ◽

Cited By ~ 571

Author(s):

Michael Baldauf ◽

Axel Seifert ◽

Jochen Förstner ◽

Detlev Majewski ◽

Matthias Raschendorfer ◽

...

Keyword(s):

Numerical Weather Prediction ◽

Weather Prediction ◽

Cloud Microphysics ◽

Squall Line ◽

Model Description ◽

Small Scale ◽

Shallow Convection ◽

Numerical Weather ◽

Advection Schemes ◽

Convective Scale

Abstract Since April 2007, the numerical weather prediction model, COSMO (Consortium for Small Scale Modelling), has been used operationally in a convection-permitting configuration, named COSMO-DE, at the Deutscher Wetterdienst (DWD; German weather service). Here the authors discuss the model changes that were necessary for the convective scale, and report on the experience from the first years of operational application of the model. For COSMO-DE the ability of the numerical solver to treat small-scale structures has been improved by using a Runge–Kutta method, which allows for the use of higher-order upwind advection schemes. The one-moment cloud microphysics parameterization has been extended by a graupel class, and adaptations for describing evaporation of rain and stratiform precipitation processes were made. Comparisons with a much more sophisticated two-moment scheme showed only minor differences in most cases with the exception of strong squall-line situations. Whereas the deep convection parameterization was switched off completely, small-scale shallow convection was still parameterized by the appropriate part of the Tiedtke scheme. During the first year of operational use, convective events in synoptically driven situations were satisfactorily simulated. Also the daily cycles of summertime 10-m wind and 1-h precipitation sums were well captured. However, it became evident that the boundary layer description had to be adapted to enhance convection initiation in airmass convection situations. Here the asymptotic Blackadar length scale l∞ had proven to be a sensitive parameter.

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The Value of a Variable Resolution Approach to Numerical Weather Prediction

Monthly Weather Review ◽

10.1175/2009mwr3077.1 ◽

2010 ◽

Vol 138 (4) ◽

pp. 1026-1042 ◽

Cited By ~ 7

Author(s):

Roberto Buizza

Keyword(s):

Numerical Weather Prediction ◽

Forecast Error ◽

Weather Prediction ◽

Model Error ◽

Prediction System ◽

Variable Resolution ◽

Numerical Weather ◽

Idealized Model ◽

Resolution System ◽

Resolution Model

Abstract It is shown that a numerical weather prediction system with variable resolution, higher in the early forecast range and lower afterward, provides more skilful forecasts than a system with constant resolution. Results indicate that the advantage can be detected also beyond the time when the resolution is truncated (truncation time). Forecasts generated with a T399 spectral truncation up to forecast day 3 and a T255 truncation from day 3 to day 8 (VAR3) are compared with forecasts generated with a constant T319 truncation. First, forecasts are verified in an idealized model error (IME) scenario against higher resolution, T799 simulations. In this scenario, VAR3 outperforms the T319 system beyond the day-3 truncation time for the entire 8-day forecast range, with differences statistically significant at the 5% level. Second, forecasts are verified in a realistic scenario against T799 analyses. In this case, although the advantage of VAR3 can still be detected beyond day 3, it is less evident and not statistically significant. Forecast error spectra indicate that using a higher-resolution model during the first forecast days improves the forecasts of the large scales, thus helping to maintain the advantage of the variable resolution system beyond the truncation time. VAR3 and T319 ensembles are also compared with forecasts with a T255, T399, and T799 constant resolution. The predictability “gain” of all ensemble configurations is measured with respect to the reference constant T255 configuration. Results show that, in the realistic scenario, VAR3 gives gains 50%–75% higher than T319 and 50%–75% lower than T799.

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Influences of Large-Scale Flow Variations on the Track Evolution of Typhoons Morakot (2009) and Megi (2010): Simulations with a Global Variable-Resolution Model

Monthly Weather Review ◽

10.1175/mwr-d-16-0363.1 ◽

2017 ◽

Vol 145 (5) ◽

pp. 1691-1716 ◽

Cited By ~ 5

Author(s):

Ching-Yuang Huang ◽

You Zhang ◽

William C. Skamarock ◽

Li-Huan Hsu

Keyword(s):

Large Scale ◽

Extreme Rainfall ◽

Mountain Range ◽

Variable Resolution ◽

The North ◽

Positive Vorticity ◽

Resolution Model ◽

Global Variable ◽

Southern Taiwan ◽

Large Scale Flow

Abstract Influences of large-scale flow variations on the track evolution of two typhoons, moderate Morakot (2009) and superintense Megi (2010), are investigated using the global variable-resolution model MPAS with a higher-resolution region of 15 km for the simulated typhoons. For Morakot, the associated track and extreme rainfall over southern Taiwan captured by MPAS compared well with the regional WRF simulations. To isolate the influences of various large-scale flows, three modes are filtered out from global reanalysis: the synoptic-scale mode, quasi-biweekly oscillation (QBW) mode, and the Madden–Julian oscillation (MJO) mode. In the absence of QBW or MJO, the simulated Morakot moves westward across Taiwan without the observed north turn after landfall. When the intensity of the MJO mode is increased by 50% in the experiment (MJO+50%), a much earlier northward turn is induced. The simulated Morakot under the observed MJO lies in between MJO+50% and MJO−50% results. The MJO variations also show similar impacts on the track evolution of Typhoon Megi. The wavenumber-1 decompositions of vorticity budget terms are shown to highlight important contributions to the vorticity tendency and typhoon translation with and without the MJO. The northward turn of both typhoons in the presence of the MJO is mainly in response to positive horizontal vorticity advection to the north of the typhoon center. However, vorticity tilting is relatively more important for Morakot due to its slantwise structure. Furthermore, positive vorticity stretching and vertical advection are significant in the vicinity of southern Taiwan due to the effects of the Central Mountain Range and tend to retard the departing Morakot.

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Next-Generation Sequencing: An Emerging Tool for Drug Designing

Current Pharmaceutical Design ◽

10.2174/1381612825666190911155508 ◽

2019 ◽

Vol 25 (31) ◽

pp. 3350-3357 ◽

Cited By ~ 1

Author(s):

Pooja Tripathi ◽

Jyotsna Singh ◽

Jonathan A. Lal ◽

Vijay Tripathi

Keyword(s):

Next Generation Sequencing ◽

High Throughput ◽

Large Scale ◽

Massively Parallel Sequencing ◽

Genomic Research ◽

Biological Research ◽

Next Generation ◽

Human Welfare ◽

Drug Designing ◽

Generation Sequencing

Background: With the outbreak of high throughput next-generation sequencing (NGS), the biological research of drug discovery has been directed towards the oncology and infectious disease therapeutic areas, with extensive use in biopharmaceutical development and vaccine production. Method: In this review, an effort was made to address the basic background of NGS technologies, potential applications of NGS in drug designing. Our purpose is also to provide a brief introduction of various Nextgeneration sequencing techniques. Discussions: The high-throughput methods execute Large-scale Unbiased Sequencing (LUS) which comprises of Massively Parallel Sequencing (MPS) or NGS technologies. The Next geneinvolved necessarily executes Largescale Unbiased Sequencing (LUS) which comprises of MPS or NGS technologies. These are related terms that describe a DNA sequencing technology which has revolutionized genomic research. Using NGS, an entire human genome can be sequenced within a single day. Conclusion: Analysis of NGS data unravels important clues in the quest for the treatment of various lifethreatening diseases and other related scientific problems related to human welfare.

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Tropical Cyclone Count Forecasting Using a Dynamical Seasonal Prediction System: Sensitivity to Improved Ocean Initialization

Journal of Climate ◽

10.1175/2010jcli3585.1 ◽

2011 ◽

Vol 24 (12) ◽

pp. 2963-2982 ◽

Cited By ~ 16

Author(s):

Andrea Alessandri ◽

Andrea Borrelli ◽

Silvio Gualdi ◽

Enrico Scoccimarro ◽

Simona Masina

Keyword(s):

Tropical Cyclone ◽

Indian Ocean ◽

Wind Shear ◽

Large Scale ◽

Initial Conditions ◽

North Pacific Ocean ◽

Convective Available Potential Energy ◽

Seasonal Prediction ◽

Boreal Summer ◽

Prediction System

Abstract This study investigates the predictability of tropical cyclone (TC) seasonal count anomalies using the Centro Euro-Mediterraneo per i Cambiamenti Climatici–Istituto Nazionale di Geofisica e Vulcanologia (CMCC-INGV) Seasonal Prediction System (SPS). To this aim, nine-member ensemble forecasts for the period 1992–2001 for two starting dates per year were performed. The skill in reproducing the observed TC counts has been evaluated after the application of a TC location and tracking detection method to the retrospective forecasts. The SPS displays good skill in predicting the observed TC count anomalies, particularly over the tropical Pacific and Atlantic Oceans. The simulated TC activity exhibits realistic geographical distribution and interannual variability, thus indicating that the model is able to reproduce the major basic mechanisms that link the TCs’ occurrence with the large-scale circulation. TC count anomalies prediction has been found to be sensitive to the subsurface assimilation in the ocean for initialization. Comparing the results with control simulations performed without assimilated initial conditions, the results indicate that the assimilation significantly improves the prediction of the TC count anomalies over the eastern North Pacific Ocean (ENP) and northern Indian Ocean (NI) during boreal summer. During the austral counterpart, significant progresses over the area surrounding Australia (AUS) and in terms of the probabilistic quality of the predictions also over the southern Indian Ocean (SI) were evidenced. The analysis shows that the improvement in the prediction of anomalous TC counts follows the enhancement in forecasting daily anomalies in sea surface temperature due to subsurface ocean initialization. Furthermore, the skill changes appear to be in part related to forecast differences in convective available potential energy (CAPE) over the ENP and the North Atlantic Ocean (ATL), in wind shear over the NI, and in both CAPE and wind shear over the SI.

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Large-scale vortices in rapidly rotating Rayleigh–Bénard convection

Journal of Fluid Mechanics ◽

10.1017/jfm.2014.542 ◽

2014 ◽

Vol 758 ◽

pp. 407-435 ◽

Cited By ~ 55

Author(s):

Céline Guervilly ◽

David W. Hughes ◽

Chris A. Jones

Keyword(s):

Large Scale ◽

Reynolds Numbers ◽

Spectral Space ◽

Small Scale ◽

Convective Velocity ◽

Onset Of Convection ◽

Convective Structures ◽

Convective Scale ◽

Domain Of Existence ◽

Convective Motions

AbstractUsing numerical simulations of rapidly rotating Boussinesq convection in a Cartesian box, we study the formation of long-lived, large-scale, depth-invariant coherent structures. These structures, which consist of concentrated cyclones, grow to the horizontal scale of the box, with velocities significantly larger than the convective motions. We vary the rotation rate, the thermal driving and the aspect ratio in order to determine the domain of existence of these large-scale vortices (LSV). We find that two conditions are required for their formation. First, the Rayleigh number, a measure of the thermal driving, must be several times its value at the linear onset of convection; this corresponds to Reynolds numbers, based on the convective velocity and the box depth, $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}{\gtrsim }100$. Second, the rotational constraint on the convective structures must be strong. This requires that the local Rossby number, based on the convective velocity and the horizontal convective scale, ${\lesssim }0.15$. Simulations in which certain wavenumbers are artificially suppressed in spectral space suggest that the LSV are produced by the interactions of small-scale, depth-dependent convective motions. The presence of LSV significantly reduces the efficiency of the convective heat transport.

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