Contribuições do segundo e do terceiro modos internos de gravidade para a resposta do movimento vertical

In earlier papers of a series of real data integrations of the National Center for Atmospheric Research Community Climate Model with tropical heat anomalies display regions of pronounced subsidence and drying located several thousand kilometers westward poleward of the heating for cases of tropical Atlantic heating and tropical east Pacific heating. This highly predictable sinking response is established within the first five days of these integrations. The normal-modes of a set of adiabatic primitive equations linearized about a basic state at rest are used to partition model response into gravity-inertia and Rossby modes. The most important contribution for the vertical motion response comes from the gravity modes added for all vertical modes. The principal emphasis is given upon the contributions of the second and third internal vertical modes (with equivalent depths on the order of a fews hundred meters) for the vertical motion response

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Uma revisão: contribuições dos modos de gravidade e de Kelvin para a resposta do movimento vertical

Anuário do Instituto de Geociências - UFRJ ◽

10.11137/2009_2_9-13 ◽

2009 ◽

Vol 32 (2) ◽

pp. 9-13

Author(s):

Julio Buchmann

Keyword(s):

Climate Model ◽

Normal Modes ◽

Vertical Motion ◽

Real Data ◽

Primitive Equations ◽

Tropical Atlantic ◽

Partition Model ◽

Atmospheric Research ◽

East Pacific ◽

Model Response

In earlier papers of a series of real data integrations of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM) with tropical heat anomalies display regions of pronounced subsidence and drying located several thousand kilometers westward poleward of the heating for cases of tropical Atlantic heating and tropical east Pacific heating. This highly predictable sinking response is established within the first five days of these integrations. The normal-modes of a set of nonlinear primitive equations for an atmosphere: Adiabatic, hydrostatic, incompressible, dry, without friction and viscosity are linearized about a basic state at rest and used to partition model response into gravity-inertia and Rossby modes. The emphasis of this review is given upon the contributions of the gravity and Kelvin modes for the vertical motion response.

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The aerosol-climate model ECHAM5-HAM

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-1125-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 1125-1156 ◽

Cited By ~ 787

Author(s):

P. Stier ◽

J. Feichter ◽

S. Kinne ◽

S. Kloster ◽

E. Vignati ◽

...

Keyword(s):

Size Distribution ◽

Climate Model ◽

Normal Modes ◽

Anthropogenic Activity ◽

Climate Modelling ◽

Extensive Evaluation ◽

Wide Range ◽

Log Normal ◽

Year 2000

Abstract. The aerosol-climate modelling system ECHAM5-HAM is introduced. It is based on a flexible microphysical approach and, as the number of externally imposed parameters is minimised, allows the application in a wide range of climate regimes. ECHAM5-HAM predicts the evolution of an ensemble of microphysically interacting internally- and externally-mixed aerosol populations as well as their size-distribution and composition. The size-distribution is represented by a superposition of log-normal modes. In the current setup, the major global aerosol compounds sulfate (SU), black carbon (BC), particulate organic matter (POM), sea salt (SS), and mineral dust (DU) are included. The simulated global annual mean aerosol burdens (lifetimes) for the year 2000 are for SU: 0.80 Tg(S) (3.9 days), for BC: 0.11 Tg (5.4 days), for POM: 0.99 Tg (5.4 days), for SS: 10.5 Tg (0.8 days), and for DU: 8.28 Tg (4.6 days). An extensive evaluation with in-situ and remote sensing measurements underscores that the model results are generally in good agreement with observations of the global aerosol system. The simulated global annual mean aerosol optical depth (AOD) is with 0.14 in excellent agreement with an estimate derived from AERONET measurements (0.14) and a composite derived from MODIS-MISR satellite retrievals (0.16). Regionally, the deviations are not negligible. However, the main patterns of AOD attributable to anthropogenic activity are reproduced.

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Comparison of the land surface climatology of the National Center for Atmospheric Research community climate model 2 at R15 and T42 resolutions

Journal of Geophysical Research Atmospheres ◽

10.1029/94jd00424 ◽

1994 ◽

Vol 99 (D5) ◽

pp. 10357 ◽

Cited By ~ 8

Author(s):

Gordon B. Bonan

Keyword(s):

Land Surface ◽

Climate Model ◽

Research Community ◽

Atmospheric Research ◽

Community Climate Model ◽

Community Climate

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Climate statistics from the National Center for Atmospheric Research community climate model CCM2

Journal of Geophysical Research Atmospheres ◽

10.1029/94jd01570 ◽

1994 ◽

Vol 99 (D10) ◽

pp. 20785 ◽

Cited By ~ 53

Author(s):

J. J. Hack ◽

B. A. Boville ◽

J. T. Kiehl ◽

P. J. Rasch ◽

D. L. Williamson

Keyword(s):

Climate Model ◽

Research Community ◽

Atmospheric Research ◽

Community Climate Model ◽

Climate Statistics ◽

Community Climate

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Correction to “A description of the global sulfur cycle and its controlling processes in the National Center for Atmospheric Research Community Climate Model, Version 3” by P. J. Rasch et al.

Journal of Geophysical Research Atmospheres ◽

10.1029/2000jd900036 ◽

2000 ◽

Vol 105 (D5) ◽

pp. 6783-6783 ◽

Cited By ~ 3

Author(s):

Philip J. Rasch ◽

Mary C. Barth ◽

Jeffrey T. Kiehl ◽

Stephen E. Schwartz ◽

Carmen M. Benkovitz

Keyword(s):

Climate Model ◽

Research Community ◽

Sulfur Cycle ◽

Atmospheric Research ◽

Community Climate Model ◽

Model Version ◽

Controlling Processes ◽

Community Climate Model Version ◽

Community Climate

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The Effect of Moist Convection on the Tropospheric Response to Tropical and Subtropical Zonally Asymmetric Torques

Journal of the Atmospheric Sciences ◽

10.1175/jas-d-13-041.1 ◽

2013 ◽

Vol 70 (12) ◽

pp. 4089-4111 ◽

Cited By ~ 5

Author(s):

William R. Boos ◽

Tiffany A. Shaw

Keyword(s):

Vertical Motion ◽

Static Stability ◽

Moist Convection ◽

Motion Response ◽

Clear Sky ◽

Double Itcz ◽

Highly Sensitive ◽

Equatorial Wave ◽

Meridional Overturning ◽

Basic States

Abstract Tropospheric winds can be altered by vertical transfers of momentum due to orographic gravity waves and convection. Previous work showed that, in dry models, such zonally asymmetric torques produce a pattern of tropical ascent that is well described by linear dynamics, together with meridional shifts of the midlatitude jet. Here a series of idealized models is used to understand the effects of moisture on the tropospheric response to tropical and subtropical zonally asymmetric, upper-tropospheric torques. The vertical motion response to a torque is shown to be amplified by the reduction in effective static stability that occurs in moist convecting atmospheres. This amplification occurs only in precipitating regions, and the magnitude of subsidence in nonprecipitating regions saturates when clear-sky radiative cooling balances induced adiabatic warming. For basic states in which precipitation is concentrated in an intertropical convergence zone (ITCZ), most of the vertical motion response is thus confined within the basic-state ITCZ, even when the torque is remote from the ITCZ. Tropical and subtropical torques perturb the extratropical baroclinic eddy field and the convectively coupled equatorial wave field. Resulting changes in momentum flux convergence by transient eddies induce secondary meridional overturning circulations that modify the zonal-mean response to a torque. The net effect allows tropical torques to merge a double ITCZ into a single equatorial ITCZ. The response of tropical transient eddies is highly sensitive to the representation of convection, so the zonal-mean response to a torque is similarly sensitive, even when the torque is located in the subtropics.

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How detailed do cloud microphysics need to be in climate models?

10.5194/egusphere-egu21-7115 ◽

2021 ◽

Author(s):

Ulrike Proske ◽

Sylvaine Ferrachat ◽

David Neubauer ◽

Ulrike Lohmann

Keyword(s):

Radiative Forcing ◽

Climate Models ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Computing Time ◽

Cloud Microphysics ◽

Model Response ◽

Microphysical Processes ◽

Improved Accuracy

Clouds are of major importance for the climate system, but the radiative forcing resulting from their interaction with aerosols remains uncertain. To improve the representation of clouds in climate models, the parameterisations of cloud microphysical processes (CMPs) have become increasingly detailed. However, more detailed climate models do not necessarily result in improved accuracy for estimates of radiative forcing (Knutti and Sedl&#225;&#269;ek, 2013; Carslaw et al., 2018). On the contrary, simpler formulations are cheaper, sufficient for some applications, and allow for an easier understanding of the respective process' effect in the model.This study aims to gain an understanding which CMP parameterisation complexity is sufficient through simplification. We gradually phase out processes such as riming or aggregation from the global climate model ECHAM-HAM, meaning that the processes are only allowed to exhibit a fraction of their effect on the model state. The shape of the model response as a function of the artificially scaled effect of a given process helps to understand the importance of this process for the model response and its potential for simplification. For example, if partially removing a process induces only minor alterations in the present day climate, this process presents as a good candidate for simplification. This may be then further investigated, for example in terms of computing time. The resulting sensitivities to CMP complexity are envisioned to guide CMP model simplifications as well as steer research towards those processes where a more accurate representation proves to be necessary.&#160; Carslaw, Kenneth, Lindsay Lee, Leighton Regayre, and Jill Johnson (Feb. 2018). &#8220;Climate Models Are Uncertain, but We Can Do Something About It&#8221;. In: Eos 99. doi: 10.1029/2018EO093757Knutti, Reto and Jan Sedl&#225;&#269;ek (Apr. 2013). &#8220;Robustness and Uncertainties in the New CMIP5 Climate Model Projections&#8221;. In: Nature Climate Change 3.4, pp. 369&#8211;373. doi: 10.1038/nclimate1716

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The Impact of Sea Surface Temperature Biases on North American Precipitation in a High-Resolution Climate Model

Journal of Climate ◽

10.1175/jcli-d-19-0417.1 ◽

2020 ◽

Vol 33 (6) ◽

pp. 2427-2447 ◽

Cited By ~ 1

Author(s):

Nathaniel C. Johnson ◽

Lakshmi Krishnamurthy ◽

Andrew T. Wittenberg ◽

Baoqiang Xiang ◽

Gabriel A. Vecchi ◽

...

Keyword(s):

North America ◽

Surface Temperature ◽

North Atlantic ◽

North American ◽

North Pacific ◽

Climate Model ◽

Sea Surface ◽

Tropical Atlantic ◽

Western North America ◽

The North

AbstractPositive precipitation biases over western North America have remained a pervasive problem in the current generation of coupled global climate models. These biases are substantially reduced, however, in a version of the Geophysical Fluid Dynamics Laboratory Forecast-Oriented Low Ocean Resolution (FLOR) coupled climate model with systematic sea surface temperature (SST) biases artificially corrected through flux adjustment. This study examines how the SST biases in the Atlantic and Pacific Oceans contribute to the North American precipitation biases. Experiments with the FLOR model in which SST biases are removed in the Atlantic and Pacific are carried out to determine the contribution of SST errors in each basin to precipitation statistics over North America. Tropical and North Pacific SST biases have a strong impact on northern North American precipitation, while tropical Atlantic SST biases have a dominant impact on precipitation biases in southern North America, including the western United States. Most notably, negative SST biases in the tropical Atlantic in boreal winter induce an anomalously strong Aleutian low and a southward bias in the North Pacific storm track. In boreal summer, the negative SST biases induce a strengthened North Atlantic subtropical high and Great Plains low-level jet. Each of these impacts contributes to positive annual mean precipitation biases over western North America. Both North Pacific and North Atlantic SST biases induce SST biases in remote basins through dynamical pathways, so a complete attribution of the effects of SST biases on precipitation must account for both the local and remote impacts.

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Dry and moist dynamics shape regional patterns of extreme precipitation sensitivity

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1913584117 ◽

2020 ◽

Vol 117 (16) ◽

pp. 8757-8763 ◽

Cited By ~ 1

Author(s):

Ji Nie ◽

Panxi Dai ◽

Adam H. Sobel

Keyword(s):

Global Warming ◽

Extreme Precipitation ◽

Large Scale ◽

Climate Model ◽

Regional Scale ◽

Vertical Motion ◽

Precipitable Water ◽

Small Scale ◽

Climate Projections ◽

Regional Patterns

Responses of extreme precipitation to global warming are of great importance to society and ecosystems. Although observations and climate projections indicate a general intensification of extreme precipitation with warming on global scale, there are significant variations on the regional scale, mainly due to changes in the vertical motion associated with extreme precipitation. Here, we apply quasigeostrophic diagnostics on climate-model simulations to understand the changes in vertical motion, quantifying the roles of dry (large-scale adiabatic flow) and moist (small-scale convection) dynamics in shaping the regional patterns of extreme precipitation sensitivity (EPS). The dry component weakens in the subtropics but strengthens in the middle and high latitudes; the moist component accounts for the positive centers of EPS in the low latitudes and also contributes to the negative centers in the subtropics. A theoretical model depicts a nonlinear relationship between the diabatic heating feedback (α) and precipitable water, indicating high sensitivity of α (thus, EPS) over climatological moist regions. The model also captures the change of α due to competing effects of increases in precipitable water and dry static stability under global warming. Thus, the dry/moist decomposition provides a quantitive and intuitive explanation of the main regional features of EPS.

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