scholarly journals Avaliação de Parametrizações de Camada Limite Planetária do Modelo WRF na Costa Norte do Nordeste do Brasil

2019 ◽  
Vol 34 (1) ◽  
pp. 9-21
Author(s):  
Natanael Vieira de Sousa ◽  
Adaiana Francisca Gomes da Silva ◽  
Gilberto Ferno Fisch ◽  
João Bosco Verçosa Leal Junior ◽  
Roberto Fernando da Fonseca Lyra ◽  
...  
Keyword(s):  
Convective Model

Resumo Este trabalho tem como objetivo avaliar duas simulações do modelo WRF que diferem em sua parametrização da Camada Limite Planetária (CLP). Foram utilizados dados de 72 radiossondas lançadas em Fortaleza (CE) entre 5 e 25 de Abril de 2011 nos horários sinóticos. A altura da CLP foi a variável avaliada e os valores observados, calculados pelo método do gradiente vertical da temperatura potencial, foram de 245±28 m para o período noturno e de 925±63 m para o período diurno. As parametrizações de CLP avaliadas foram Asymmetric Convective Model V2 e Mellor Yamada Nakanish and Niino 2.5. O desempenho destas foi avaliado por comparação estatística com dados observados, utilizando-se o Erro Médio Absoluto (EMA) e o índice refinado de concordância de Willmott (dr). Para a ACM2 obtiveram-se valores de EMA iguais a 282 m e 519 m e dr de 0,53 e 0,37, respectivamente, para os períodos noturno e diurno. Com MYNN2,5, foram encontrados valores de EMA entre 312 m e 266 m, com dr entre 0,59 e 0,56 para os períodos noturno ediurno, respectivamente. A parametrização MYNN2,5 mostrou-se mais eficiente, considerando ambas as métricas. No entanto, somente para 00UTC, a ACM2 apresentou melhor desempenho.

An investigation of Pluto’s troposphere using stellar occultation light curves and an atmospheric radiative–conductive–convective model

Icarus ◽  
2011 ◽  
Vol 214 (2) ◽  
pp. 685-700 ◽  
Author(s):  
Angela M. Zalucha ◽  
Xun Zhu ◽  
Amanda A.S. Gulbis ◽  
Darrell F. Strobel ◽  
J.L. Elliot
Keyword(s):  
Light Curves ◽  
Stellar Occultation ◽  
Convective Model

Sensitivity Analysis of a Radiative-Convective Model by the Adjoint Method

1982 ◽  
Vol 39 (9) ◽  
pp. 2038-2050 ◽  
Author(s):  
Matthew C. G. Hall ◽  
Dan G. Cacuci ◽  
Michael E. Schlesinger
Keyword(s):  
Sensitivity Analysis ◽  
Adjoint Method ◽  
Convective Model

Closure to “Convective Model of Longitudinal Dispersion”

1978 ◽  
Vol 104 (1) ◽  
pp. 129-132
Author(s):  
Raul S. McQuivey ◽  
Thomas N. Keefer
Keyword(s):  
Longitudinal Dispersion ◽  
Convective Model

scholarly journals A finite-difference convective model for Jupiter's equatorial jet

2006 ◽  
Vol 2 (S239) ◽  
pp. 230-232 ◽  
Author(s):  
Kwing L. Chan
Keyword(s):  
Reynolds Number ◽  
Numerical Model ◽  
Finite Difference ◽  
Spherical Shell ◽  
Reynolds Stress ◽  
Momentum Equation ◽  
Momentum Balance ◽  
Zonal Momentum Balance ◽  
Zonal Momentum ◽  
Convective Model

AbstractWe present results of a numerical model for studying the dynamics of Jupiter's equatorial jet. The computed domain is a piece of spherical shell around the equator. The bulk of the region is convective, with a thin radiative layer at the top. The shell is spinning fast, with a Coriolis number = ΩL/V on the order of 50. A prominent super-rotating equatorial jet is generated, and secondary alternating jets appear in the higher latitudes. The roles of terms in the zonal momentum equation are analyzed. Since both the Reynolds number and the Taylor number are large, the viscous terms are small. The zonal momentum balance is primarily between the Coriolis and the Reynolds stress terms.

scholarly journals Model-dependence of the CO<sub>2</sub> threshold for melting the hard Snowball Earth

2011 ◽  
Vol 7 (1) ◽  
pp. 17-25 ◽  
Author(s):  
Y. Hu ◽  
J. Yang ◽  
F. Ding ◽  
W. R. Peltier
Keyword(s):  
Surface Temperature ◽  
Greenhouse Effect ◽  
Surface Albedo ◽  
Snowball Earth ◽  
Pressure Broadening ◽  
Near Surface ◽  
Induced Absorption ◽  
Cloud Forcing ◽  
Clear Sky ◽  
Convective Model

Abstract. One of the critical issues of the Snowball Earth hypothesis is the CO2 threshold for triggering the deglaciation. Using Community Atmospheric Model version 3.0 (CAM3), we study the problem for the CO2 threshold. Our simulations show large differences from previous results (e.g. Pierrehumbert, 2004, 2005; Le Hir et al., 2007). At 0.2 bars of CO2, the January maximum near-surface temperature is about 268 K, about 13 K higher than that in Pierrehumbert (2004, 2005), but lower than the value of 270 K for 0.1 bar of CO2 in Le Hir et al. (2007). It is found that the difference of simulation results is mainly due to model sensitivity of greenhouse effect and longwave cloud forcing to increasing CO2. At 0.2 bars of CO2, CAM3 yields 117 Wm−2 of clear-sky greenhouse effect and 32 Wm−2 of longwave cloud forcing, versus only about 77 Wm−2 and 10.5 Wm−2 in Pierrehumbert (2004, 2005), respectively. CAM3 has comparable clear-sky greenhouse effect to that in Le Hir et al. (2007), but lower longwave cloud forcing. CAM3 also produces much stronger Hadley cells than that in Pierrehumbert (2005). Effects of pressure broadening and collision-induced absorption are also studied using a radiative-convective model and CAM3. Both effects substantially increase surface temperature and thus lower the CO2 threshold. The radiative-convective model yields a CO2 threshold of about 0.21 bars with surface albedo of 0.663. Without considering the effects of pressure broadening and collision-induced absorption, CAM3 yields an approximate CO2 threshold of about 1.0 bar for surface albedo of about 0.6. However, the threshold is lowered to 0.38 bars as both effects are considered.

scholarly journals Convection and Dynamo in Newly Born Neutron Stars

2022 ◽  
Vol 924 (2) ◽  
pp. 75
Author(s):  
Youhei Masada ◽  
Tomoya Takiwaki ◽  
Kei Kotake
Keyword(s):  
Spherical Shell ◽  
Neutron Stars ◽  
Large Scale ◽  
Convection Zone ◽  
Turbulent Transport ◽  
Mean Field ◽  
Magnetic Component ◽  
Large Scale Structures ◽  
Scale Structures ◽  
Convective Model

Abstract To study properties of magnetohydrodynamic (MHD) convection and resultant dynamo activities in proto-neutron stars (PNSs), we construct a “PNS in a box” simulation model and solve the compressible MHD equation coupled with a nuclear equation of state (EOS) and simplified leptonic transport. As a demonstration, we apply it to two types of PNS model with different internal structures: a fully convective model and a spherical-shell convection model. By varying the spin rate of the models, the rotational dependence of convection and the dynamo that operate inside the PNS is investigated. We find that, as a consequence of turbulent transport by rotating stratified convection, large-scale structures of flow and thermodynamic fields are developed in all models. Depending on the spin rate and the depth of the convection zone, various profiles of the large-scale structures are obtained, which can be physically understood as steady-state solutions to the “mean-field” equation of motion. Additionally to those hydrodynamic structures, a large-scale magnetic component of  ( 10 15 ) G is also spontaneously organized in disordered tangled magnetic fields in all models. The higher the spin rate, the stronger the large-scale magnetic component grows. Intriguingly, as an overall trend, the fully convective models have a stronger large-scale magnetic component than that in the spherical-shell convection models. The deeper the convection zone extends, the larger the size of the convective eddies becomes. As a result, rotationally constrained convection seems to be more easily achieved in the fully convective model, resulting in a higher efficiency of the large-scale dynamo there. To gain a better understanding of the origin of the diversity of a neutron star’s magnetic field, we need to study the PNS dynamo in a wider parameter range.

Closure to “Convective Model of Longitudinal Dispersion”

1979 ◽  
Vol 105 (4) ◽  
pp. 419-420
Author(s):  
Raul S. McQuivey ◽  
Thomas N. Keefer
Keyword(s):  
Longitudinal Dispersion ◽  
Convective Model
Sign in / Sign up

Export Citation Format

Share Document