Impact of atmospheric model resolution on simulation of ENSO feedback processes: a coupled model study

Abstract. In alpine regions, wind-induced snow transport strongly influences the spatio-temporal evolution of the snow cover throughout the winter season. To gain understanding on the complex processes that drive the redistribution of snow, a new numerical model is developed. It couples directly the detailed snowpack model Crocus with the atmospheric model Meso-NH. Meso-NH/Crocus simulates snow transport in saltation and in turbulent suspension and includes the sublimation of suspended snow particles. A detailed representation of the first meters of the atmosphere allows a fine reproduction of the erosion and deposition process. The coupled model is evaluated against data collected around the experimental site of Col du Lac Blanc (2720 m a.s.l., French Alps). For this purpose, a blowing snow event without concurrent snowfall has been selected and simulated. Results show that the model captures the main structures of atmospheric flow in alpine terrain, the vertical profile of wind speed and the snow particles fluxes near the surface. However, the horizontal resolution of 50 m is found to be insufficient to simulate the location of areas of snow erosion and deposition observed by terrestrial laser scanning. When activated, the sublimation of suspended snow particles causes a reduction in deposition of 5.3%. Total sublimation (surface + blowing snow) is three times higher than surface sublimation in a simulation neglecting blowing snow sublimation.

Download Full-text

The co-influence of the sea breeze and the coastal upwelling at Cabo Frio: a numerical investigation using coupled models

Brazilian Journal of Oceanography ◽

10.1590/s1679-87592011000200002 ◽

2011 ◽

Vol 59 (2) ◽

pp. 131-144 ◽

Cited By ~ 5

Author(s):

Flávia Noronha Dutra Ribeiro ◽

Jacyra Soares ◽

Amauri Pereira de Oliveira

Keyword(s):

Positive Feedback ◽

Coastal Upwelling ◽

Coupled Model ◽

Sea Breeze ◽

Atmospheric Model ◽

Breeze Circulation ◽

Coupled Models ◽

Initial Field ◽

Oceanic Model ◽

Cabo Frio

A coupled atmospheric-oceanic model was used to investigate whether there is a positive feedback between the coastal upwelling and the sea breeze at Cabo Frio - RJ (Brazil). Two experiments were performed to ascertain the influence of the sea breeze on the coastal upwelling: the first one used the coupled model forced with synoptic NE winds of 8 m s-1 and the sign of the sea breeze circulation was set by the atmospheric model; the second experiment used only the oceanic model with constant 8 m s-1 NE winds. Then, to study the influence of the coastal upwelling on the sea breeze, two more experiments were performed: one using a coastal upwelling representative SST initial field and the other one using a constant and homogeneous SST field of 26°C. Finally, two more experiments were conducted to verify the influence of the topography and the spatial distribution of the sea surface temperature on the previous results. The results showed that the sea breeze can intensify the coastal upwelling, but the coastal upwelling does not intensify the sea breeze circulation, suggesting that there is no positive feedback between these two phenomena at Cabo Frio.

Download Full-text

Introduction to A Regional Coupled Forecasting System

10.5194/egusphere-egu2020-12626 ◽

2020 ◽

Author(s):

Mingkui Li ◽

Shaoqing Zhang

Keyword(s):

National Laboratory ◽

Coupled Model ◽

Ocean Model ◽

Asia Pacific ◽

Model Resolution ◽

Coupled Models ◽

Regional Ocean Model System ◽

Extended Range ◽

Coupled Data Assimilation ◽

The Impact

<p>A regional coupled prediction system for the Asia-Pacific area (AP-RCP) has been established. The AP-RCP system consists of WRF-ROMS (Weather Research and Forecast and Regional Ocean Model System) coupled models combined with local observing information through dynamically downscaling coupled data assimilation. The system generates 18-day atmospheric and oceanic environment forecasts on a daily quasi-operational schedule at Qingdao Pilot National Laboratory for Marine Science and Technology (QNLM). The AP-RCP system mainly includes 2 different coupled model resolutions: 27km WRF coupled with 9km ROMS, and 9km WRF coupled with 3km ROMS. This study evaluates the impact of enhancing coupled model resolution on the extended-range forecasts, focusing on forecasts of typhoon onset, and improved precipitation and typhoon intensity forecasts. Results show that enhancing coupled model resolution is a necessary step to realize the extended-range predictability of the atmosphere and ocean environmental conditions that include a plenty of local details. The next challenges include improving the planetary boundary physics and the representation of air-sea and air-land interactions when the model can resolve the kilometer or sub-kilometer processes.</p>

Download Full-text

Sensitivity of the Aerosol Indirect Effect to Subgrid Variability in the Cloud Parameterization of the GFDL Atmosphere General Circulation Model AM3

Journal of Climate ◽

10.1175/2010jcli3945.1 ◽

2011 ◽

Vol 24 (13) ◽

pp. 3145-3160 ◽

Cited By ~ 81

Author(s):

Jean-Christophe Golaz ◽

Marc Salzmann ◽

Leo J. Donner ◽

Larry W. Horowitz ◽

Yi Ming ◽

...

Keyword(s):

General Circulation Model ◽

Indirect Effect ◽

General Circulation ◽

Coupled Model ◽

Circulation Model ◽

Atmospheric Model ◽

Radiation Balance ◽

Cloud Drop ◽

Aerosol Indirect Effect ◽

Alternate Model

Abstract The recently developed GFDL Atmospheric Model version 3 (AM3), an atmospheric general circulation model (GCM), incorporates a prognostic treatment of cloud drop number to simulate the aerosol indirect effect. Since cloud drop activation depends on cloud-scale vertical velocities, which are not reproduced in present-day GCMs, additional assumptions on the subgrid variability are required to implement a local activation parameterization into a GCM. This paper describes the subgrid activation assumptions in AM3 and explores sensitivities by constructing alternate configurations. These alternate model configurations exhibit only small differences in their present-day climatology. However, the total anthropogenic radiative flux perturbation (RFP) between present-day and preindustrial conditions varies by ±50% from the reference, because of a large difference in the magnitude of the aerosol indirect effect. The spread in RFP does not originate directly from the subgrid assumptions but indirectly through the cloud retuning necessary to maintain a realistic radiation balance. In particular, the paper shows a linear correlation between the choice of autoconversion threshold radius and the RFP. Climate sensitivity changes only minimally between the reference and alternate configurations. If implemented in a fully coupled model, these alternate configurations would therefore likely produce substantially different warming from preindustrial to present day.

Download Full-text

Future sea-level rise due to projected ocean warming beneath the Filchner Ronne Ice Shelf: A coupled model study

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2015.09.013 ◽

2015 ◽

Vol 431 ◽

pp. 217-224 ◽

Cited By ~ 16

Author(s):

Malte Thoma ◽

Jürgen Determann ◽

Klaus Grosfeld ◽

Sebastian Goeller ◽

Hartmut H. Hellmer

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Coupled Model ◽

Ocean Warming ◽

Ice Shelf ◽

Model Study

Download Full-text

A coupled model study on the intensification of the Asian summer monsoon in IPCC SRES Scenarios

Advances in Atmospheric Sciences ◽

10.1007/bf02918680 ◽

2005 ◽

Vol 22 (6) ◽

pp. 798-806 ◽

Cited By ~ 7

Author(s):

Min Wei

Keyword(s):

Summer Monsoon ◽

Asian Summer Monsoon ◽

Coupled Model ◽

Model Study ◽

Asian Summer ◽

Sres Scenarios ◽

Ipcc Sres ◽

Ipcc Sres Scenarios

Download Full-text

The New GFDL Global Atmosphere and Land Model AM2–LM2: Evaluation with Prescribed SST Simulations

Journal of Climate ◽

10.1175/jcli-3223.1 ◽

2004 ◽

Vol 17 (24) ◽

pp. 4641-4673 ◽

Cited By ~ 617

Keyword(s):

Climate Model ◽

Southern Oscillation ◽

Coupled Model ◽

Atmospheric Model ◽

Stomatal Resistance ◽

Cold Bias ◽

Geophysical Fluid Dynamics Laboratory ◽

Latent Heat Storage ◽

Reliable Assessment ◽

And Performance

Abstract The configuration and performance of a new global atmosphere and land model for climate research developed at the Geophysical Fluid Dynamics Laboratory (GFDL) are presented. The atmosphere model, known as AM2, includes a new gridpoint dynamical core, a prognostic cloud scheme, and a multispecies aerosol climatology, as well as components from previous models used at GFDL. The land model, known as LM2, includes soil sensible and latent heat storage, groundwater storage, and stomatal resistance. The performance of the coupled model AM2–LM2 is evaluated with a series of prescribed sea surface temperature (SST) simulations. Particular focus is given to the model's climatology and the characteristics of interannual variability related to E1 Niño– Southern Oscillation (ENSO). One AM2–LM2 integration was performed according to the prescriptions of the second Atmospheric Model Intercomparison Project (AMIP II) and data were submitted to the Program for Climate Model Diagnosis and Intercomparison (PCMDI). Particular strengths of AM2–LM2, as judged by comparison to other models participating in AMIP II, include its circulation and distributions of precipitation. Prominent problems of AM2– LM2 include a cold bias to surface and tropospheric temperatures, weak tropical cyclone activity, and weak tropical intraseasonal activity associated with the Madden–Julian oscillation. An ensemble of 10 AM2–LM2 integrations with observed SSTs for the second half of the twentieth century permits a statistically reliable assessment of the model's response to ENSO. In general, AM2–LM2 produces a realistic simulation of the anomalies in tropical precipitation and extratropical circulation that are associated with ENSO.

Download Full-text

Fast responses on pre-industrial climate from present-day aerosols in a CMIP6 multi-model study

10.5194/acp-2019-1201 ◽

2020 ◽

Author(s):

Prodromos Zanis ◽

Dimitris Akritidis ◽

Aristeidis K. Georgoulias ◽

Robert J. Allen ◽

Susanne E. Bauer ◽

...

Keyword(s):

Northern Hemisphere ◽

Radiative Forcing ◽

General Circulation ◽

Coupled Model ◽

General Circulation Models ◽

The Arctic ◽

Model Study ◽

Southward Shift ◽

Temperature Responses ◽

Circulation Changes

Abstract. In this work, we use Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations from 10 Earth System Models (ESMs) and General Circulation Models (GCMs) to study the fast climate responses on pre-industrial climate, due to present-day aerosols. All models carried out two sets of simulations; a control experiment with all forcings set to the year 1850 and a perturbation experiment with all forcings identical to the control, except for aerosols with precursor emissions set to the year 2014. In response to the pattern of all aerosols effective radiative forcing (ERF), the fast temperature responses are characterised by cooling over the continental areas, especially in the Northern Hemisphere, with the largest cooling over East Asia and India, sulfate being the dominant aerosol surface temperature driver for present-day emissions. In the Arctic there is a warming signal for winter in the ensemble mean of fast temperature responses, but the model-to-model variability is large, and it is presumably linked to aerosol induced circulation changes. The largest fast precipitation responses are seen in the tropical belt regions, generally characterized by a reduction over continental regions and a southward shift of the tropical rain belt. This is a characteristic and robust feature among most models in this study, associated with a southward shift of the Intertropical convergence zone (ITCZ) and a weakening of the monsoon systems around the globe (Asia, Africa and America) in response to hemispherically asymmetric cooling from a Northern Hemisphere aerosol perturbation, leading the ITCZ and tropical precipitation to shift away from the cooled hemispheric pattern. An interesting feature in aerosol induced circulation changes is a characteristic dipole pattern with intensification of the Icelandic Low and an anticyclonic anomaly over Southeastern Europe, inducing warm air advection towards the northern polar latitudes in winter.

Download Full-text