Toward Cloud Resolving Modeling of Large-Scale Tropical Circulations: A Simple Cloud Microphysics Parameterization

Grabowski, Wojciech W.

doi:10.1175/1520-0469(1998)055<3283:tcrmol>2.0.co;2

Cited by 189 publications

(255 citation statements)

References 37 publications

Supporting

Mentioning

248

Contrasting

Order By: Relevance

“…If more emphasis is placed on the analysis of mesoscale convective features (Yamasaki 2006), the implementation is likely to be significant. We used a cloud microphysics scheme (Grabowski 1998) that treats two classes of solid phases consisting of cloud ice and snow. Major improvements in the physical schemes from the previous version of the model ) include an upgraded version of the turbulent boundary layer scheme (Nakanishi and Niino 2004), in which the thermodynamical effects of the subgrid scale condensation were incorporated (Noda et al 2008).…”

Section: Methodsmentioning

confidence: 99%

A Simulated Preconditioning of Typhoon Genesis Controlled by a Boreal Summer Madden-Julian Oscillation Event in a Global Cloud-system-resolving Model

Oouchi

Noda

Satoh

et al. 2009

SOLA

View full text Add to dashboard Cite

A preconditioning of a typhoon genesis over the North Western Pacific by an Madden-Julian Oscillation (MJO) event is simulated in a boreal summer numerical experiment conducted using a global cloud-systemresolving model. The simulation highlights the importance of the following processes in the typhoon genesis that were not clearly captured in the conventional general circulation models: as the MJO propagates over that region, the easterly shear (with an enhanced lowlevel westerly) of the western branch of the MJO's circulation moderates the climatological westerly shear that is otherwise persistent and inhibits cyclogenesis there. Meanwhile, its attendant cyclonic vorticity from the westerly region migrates northward, causing the genesis to occur. The trough in the upper troposphere at 15° 20°N is found to contribute to the genesis. The result demonstrates the performance of a global cloudsystem-resolving model at predicting tropical cyclogenesis associated with the MJO in the North Western Pacific during the active typhoon season in boreal summer. IntroductionImproving the prediction of tropical cyclogenesis has broad socioeconomic impacts. The need for improvement has been high in the weather forecasting field and will be higher in the future, greenhousewarmed climate condition, when tropical cyclones are projected to become more intense (IPCC 2007) and destructive. Our current understanding of the genesis process remains fragmentary despite the expanded observational network in the tropics after a seminal article (Yanai 1964) on the issue. It was in the past few decades that observational studies suggested a possible link between the MJO, a planetary-scale and quasi-periodic tropical weather event, and statistics of tropical cyclogenesis over some oceanic basins, including the North Western Pacific (Nakazawa 1986).In terms of the modeling approach, both the MJO (Lin et al. 2006) and tropical cyclogenesis are elusive factors. Clouds drive both phenomena, and difficulty in handling a cloud spanning less than the grid spacing of a given model has always hampered our understanding of the phenomena. Atmospheric general circulation models (GCMs) typically use a grid spacing of O (100 km) or so to cover the globe, and the simulated cloud disturbances are too fuzzy to pick up anything as small as a tropical cyclone in the genesis stage and the clouds embedded in an MJO. A way to avoid this difficulty is cumulus convection parameterisation, which was typically subject to uncertainties when implemented in conventional GCMs. The most compelling difficulty is its inability to represent mechanisms associated with mesoscale convection, a key convective element of O (10 km) scale in tropical cyclones (Yamasaki 1986(Yamasaki , 2006) and the MJO (Oouchi and Yamasaki 2001).Alternatively, a "global" cloud-system-resolving model (GCSRM) was suggested. The advent of the Earth Simulator facilitated this computationally intensive calculation. The Nonhydrostatic ICosahedral Atmospheric Model (NICAM) Tomita and Satoh 2004) i...

show abstract

Section: Methodsmentioning

confidence: 99%

A Simulated Preconditioning of Typhoon Genesis Controlled by a Boreal Summer Madden-Julian Oscillation Event in a Global Cloud-system-resolving Model

Oouchi

Noda

Satoh

et al. 2009

SOLA

View full text Add to dashboard Cite

show abstract

“…However, given the physical reasoning discussed above and the support of this reasoning based on observations and theoretical work, it is probably unreasonable to expect that these relationships even qualitatively describe the relationship between the local values of the shape parameter and droplet concentrations within clouds. Instead, it appears that parameterizations such as the one proposed by Grabowski (1998) (dashed gray line in Fig. 7a) are more suitable for largeeddy simulations.…”

Section: Implication For Parameterizationsmentioning

confidence: 98%

“…With this relationship, D n can be solved for if n is known. However, in single-and double-moment bulk microphysics schemes, n is not known, and must be set to some constant value or diagnosed in some other way (Grabowski 1998;Rotstayn and Liu 2003;Morrison and Grabowski 2007;Thompson et al 2008;Geoffroy et al 2010). On the other hand, triplemoment schemes (Milbrandt and Yau 2005b;Shipway and Hill 2012;Loftus and Cotton 2014), which additionally predict the sixth moment of the distribution, can explicitly solve for this remaining parameter of the gamma distribution.…”

Section: Introductionmentioning

confidence: 99%

The Importance of the Shape of Cloud Droplet Size Distributions in Shallow Cumulus Clouds. Part I: Bin Microphysics Simulations

Igel

Heever

2017

Journal of the Atmospheric Sciences

View full text Add to dashboard Cite

In this two-part study, the relationships between the width of the cloud droplet size distribution and the microphysical processes and cloud characteristics of nonprecipitating shallow cumulus clouds are investigated using large-eddy simulations. In Part I, simulations are run with a bin microphysics scheme and the relative widths (standard deviation divided by mean diameter) of the simulated cloud droplet size distributions are calculated. They reveal that the value of the relative width is higher and less variable in the subsaturated regions of the cloud than in the supersaturated regions owing to both the evaporation process itself and enhanced mixing and entrainment of environmental air. Unlike in some previous studies, the relative width is not found to depend strongly on the initial aerosol concentration or mean droplet concentration. Nonetheless, local values of the relative width are found to positively correlate with local values of the droplet concentrations, particularly in the supersaturated regions of clouds. In general, the distributions become narrower as the local droplet concentration increases, which is consistent with the difference in relative width between the supersaturated and subsaturated cloud regions and with physically based expectations. Traditional parameterizations for the relative width (or shape parameter, a related quantity) of cloud droplet size distributions in bulk microphysics schemes are based on cloud mean values, but the bin simulation results shown here demonstrate that more appropriate parameterizations should be based on the relationship between the local values of the relative width and the cloud droplet concentration.

show abstract

“…The model in Eq. 10 already incorporates a number of key features at large scales in a CRM method for the equatorial wave guide (7)(8)(9). The CRM approach on the coarse-grained large scales would involve additional nonlinear advection terms in Eq.…”

Section: The Equatorial Primitive Equationsmentioning

confidence: 99%

“…therein). A particularly promising emerging approach to address these issues is cloud-resolving modeling (CRM), where idealized highly resolved two-dimensional simulations of clouds are coupled to largerscale dynamics in a variety of ways (7)(8)(9), utilizing massively parallel computer architecture. Nevertheless, only very crude resolution of the large-scale interaction is possible with the current generation of computers.…”

mentioning

confidence: 99%

A numerical strategy for efficient modeling of the equatorial wave guide

Majda¹

2001

Proceedings of the National Academy of Sciences

View full text Add to dashboard Cite

Convection in the tropics is observed to involve a wide-ranging hierarchy of scales from a few kilometers to the planetary scales and also has a profound impact on short-term climate. The mechanisms responsible for this behavior present a major unsolved problem. A promising emerging approach to address these issues is cloudresolving modeling. Here a family of numerical models is introduced specifically to model the feedback of small-scale deep convection on tropical planetary waves and tropical circulation in a highly efficient manner compatible with the approach through cloud-resolving modeling. Such a procedure is also useful for theoretical purposes. The basic idea in the approach is to use low-order truncation in the meriodonal direction through Gauss-Hermite quadrature projected onto a simple discrete radiation condition. In this fashion, the cloudresolving modeling of equatorially trapped planetary waves reduces to the solution of a small number of purely zonal two-dimensional wave systems along a few judiciously chosen meriodonal layers that are coupled only by some additional source terms. The approach is analyzed in detail with full mathematical rigor for linearized equatorial primitive equations with source terms.C onvection in the tropics has a profound impact on short-term climate. Observational data indicate that tropical deep convection is organized on a hierarchy of scales ranging from cumulus clouds over a few kilometers to interseasonal oscillations over planetary scales of order 40,000 km (1-3). The mechanisms for this behavior present a major unsolved problem, despite the fact that there has been extensive research over the last few decades on these topics through parameterization of convection in general circulation models (4) as well as theory (refs. 5 and 6 and refs. therein). A particularly promising emerging approach to address these issues is cloud-resolving modeling (CRM), where idealized highly resolved two-dimensional simulations of clouds are coupled to largerscale dynamics in a variety of ways (7-9), utilizing massively parallel computer architecture. Nevertheless, only very crude resolution of the large-scale interaction is possible with the current generation of computers. Here a hierarchy of numerical models is introduced specifically to model the feedback of small-scale deep convection on the tropical planetary waves and tropical circulation in a highly efficient manner compatible with the CRM approach. Besides its efficiency, this numerical strategy also makes a direct link with many of the observed larger-scale patterns in the equatorial wave guide such as Kelvin, Yanai, and equatorial Rossby waves (3, 10, 11), so that observations, theory, and CRM simulations can be compared in an interactive fashion.The basic idea in the approach is to use low-order truncation in the meriodonal direction through Hermite polynomials combined with Gauss-Hermite quadrature in a meriodonal Galerkin approximation projected onto a simple discrete radiation condition. In this fashion, for example, ...

show abstract

Toward Cloud Resolving Modeling of Large-Scale Tropical Circulations: A Simple Cloud Microphysics Parameterization

Cited by 189 publications

References 37 publications

A Simulated Preconditioning of Typhoon Genesis Controlled by a Boreal Summer Madden-Julian Oscillation Event in a Global Cloud-system-resolving Model

A Simulated Preconditioning of Typhoon Genesis Controlled by a Boreal Summer Madden-Julian Oscillation Event in a Global Cloud-system-resolving Model

The Importance of the Shape of Cloud Droplet Size Distributions in Shallow Cumulus Clouds. Part I: Bin Microphysics Simulations

A numerical strategy for efficient modeling of the equatorial wave guide

Contact Info

Product

Resources

About