The Experts below are selected from a list of 57363 Experts worldwide ranked by ideXlab platform
Johann H. Jungclaus - One of the best experts on this subject based on the ideXlab platform.
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high atmospheric Horizontal Resolution eliminates the wind driven coastal warm bias in the southeastern tropical atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
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High atmospheric Horizontal Resolution eliminates the wind‐driven coastal warm bias in the southeastern tropical Atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
Jay F. Shriver - One of the best experts on this subject based on the ideXlab platform.
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On Eddy Viscosity, Energy Cascades, and the Horizontal Resolution of Gridded Satellite Altimeter Products*
Journal of Physical Oceanography, 2013Co-Authors: Brian K. Arbic, Kurt L. Polzin, Robert B. Scott, James G. Richman, Jay F. ShriverAbstract:Motivated by the recent interest in ocean energetics, the widespread use of Horizontal eddy viscosity in models, and the promise of high Horizontal Resolution data from the planned wide-swath satellite altimeter, this paper explores the impacts of Horizontal eddy viscosity and Horizontal grid Resolution on geostrophic turbulence, with a particular focus on spectral kinetic energy fluxes P(K) computed in the isotropic wavenumber (K) domain. The paper utilizes idealized two-layer quasigeostrophic (QG) models, realistic highResolution ocean general circulation models, and present-generation gridded satellite altimeter data. Adding Horizontal eddy viscosity to the QG model results in a forward cascade at smaller scales, in apparent agreement with results from present-generation altimetry. Eddy viscosity is taken to roughly represent coupling of mesoscale eddies to internal waves or to submesoscale eddies. Filtering the output of either the QG or realistic models before computing P(K) also greatly increases the forward cascade. Such filtering mimics the smoothing inherent in the construction of present-generation gridded altimeter data. It is therefore difficult to say whether the forward cascades seen in present-generation altimeter data are due to real physics (represented here by eddy viscosity) or to insufficient Horizontal Resolution. The inverse cascade at larger scales remains in the models even after filtering, suggesting that its existence in the models and in altimeterdata is robust.However,themagnitudeofthe inverse cascadeis affectedbyfiltering,suggestingthat the wide-swath altimeter will allow a more accurate determination of the inverse cascade at larger scales as well as providing important constraints on smaller-scale dynamics.
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On Eddy Viscosity, Energy Cascades, and the Horizontal Resolution of Gridded Satellite Altimeter
Journal of Physical Oceanography, 2013Co-Authors: Brian K. Arbic, Kurt L. Polzin, Robert B. Scott, James G. Richman, Jay F. ShriverAbstract:Motivated by the recent interest in ocean energetics, the widespread use of Horizontal eddy viscosity in models, and the promise of high Horizontal Resolution data from the planned wide-swath satellite altimeter, this paper explores the impacts of Horizontal eddy viscosity and Horizontal grid Resolution on geostrophic turbulence, with a particular focus on spectral kinetic energy fluxes Π(K) computed in the isotropic wavenumber (K) domain. The paper utilizes idealized two-layer quasigeostrophic (QG) models, realistic high-Resolution ocean general circulation models, and present-generation gridded satellite altimeter data. Adding Horizontal eddy viscosity to the QG model results in a forward cascade at smaller scales, in apparent agreement with results from present-generation altimetry. Eddy viscosity is taken to roughly represent coupling of mesoscale eddies to internal waves or to submesoscale eddies. Filtering the output of either the QG or realistic models before computing Π(K) also greatly increases the forward cascade. Such filtering mimics the smoothing inherent in the construction of present-generation gridded altimeter data. It is therefore difficult to say whether the forward cascades seen in present-generation altimeter data are due to real physics (represented here by eddy viscosity) or to insufficient Horizontal Resolution. The inverse cascade at larger scales remains in the models even after filtering, suggesting that its existence in the models and in altimeter data is robust. However, the magnitude of the inverse cascade is affected by filtering, suggesting that the wide-swath altimeter will allow a more accurate determination of the inverse cascade at larger scales as well as providing important constraints on smaller-scale dynamics.
Jürgen Bader - One of the best experts on this subject based on the ideXlab platform.
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high atmospheric Horizontal Resolution eliminates the wind driven coastal warm bias in the southeastern tropical atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
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High atmospheric Horizontal Resolution eliminates the wind‐driven coastal warm bias in the southeastern tropical Atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
Sebastian Milinski - One of the best experts on this subject based on the ideXlab platform.
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high atmospheric Horizontal Resolution eliminates the wind driven coastal warm bias in the southeastern tropical atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
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High atmospheric Horizontal Resolution eliminates the wind‐driven coastal warm bias in the southeastern tropical Atlantic
Geophysical Research Letters, 2016Co-Authors: Sebastian Milinski, Jürgen Bader, Helmuth Haak, Angela Cheska Siongco, Johann H. JungclausAbstract:We investigate the strong warm bias in sea surface temperatures (SST) of the southeastern tropical Atlantic that occurs in most of the current global climate models. We analyse this bias in the Max Planck Institute Earth System Model at different Horizontal Resolutions ranging from 0.1° to 0.4° in the ocean and 0.5° to 1.8° in the atmosphere. High atmospheric Horizontal Resolution eliminates the SST bias close to the African coast, due to an improved representation of surface wind-stress near the coast. This improvement affects coastal upwelling and Horizontal ocean circulation, as confirmed with dedicated sensitivity experiments. The wind-stress improvements are partly caused by the better represented orography at higher Horizontal Resolution in the spectral atmospheric model. The reductions of the coastal SST bias obtained through higher Horizontal Resolution do not, however, translate to a reduction of the large-scale bias extending westward from the African coast into the southeastern tropical Atlantic.
Christopher E. Holloway - One of the best experts on this subject based on the ideXlab platform.
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Role of atmospheric Horizontal Resolution in simulating tropical and subtropical South American precipitation in HadGEM3-GC31
Geoscientific Model Development, 2020Co-Authors: Paul-arthur Monerie, Amulya Chevuturi, Peter Cook, Nick Klingaman, Christopher E. HollowayAbstract:Abstract. We assess the effect of increasing Horizontal Resolution on simulated precipitation over South America in a climate model. We use atmosphere-only simulations, performed with HadGEM3-GC31 at three Horizontal Resolutions: N96 (∼130 km; 1.88∘×1.25∘), N216 (∼60 km; 0.83∘×0.56∘), and N512 (∼25 km; 0.35∘×0.23∘). We show that all simulations have systematic biases in annual mean and seasonal mean precipitation over South America (e.g. too wet over the Amazon and too dry in the northeast). Increasing Horizontal Resolution improves simulated precipitation over the Andes and northeast Brazil. Over the Andes, improvements from Horizontal Resolution continue to ∼25 km, while over northeast Brazil, there are no improvements beyond ∼60 km Resolution. These changes are primarily related to changes in atmospheric dynamics and moisture flux convergence. Over the Amazon Basin, precipitation variability increases at higher Resolution. We show that some spatial and temporal features of daily South American precipitation are improved at high Resolution, including the intensity spectra of rainfall. Spatial scales of daily precipitation features are also better simulated, suggesting that higher Resolution may improve the representation of South American mesoscale convective systems.
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Role of atmospheric Horizontal Resolution in simulating tropical and subtropical South American precipitation in HadGEM3-GC31
2020Co-Authors: Paul-arthur Monerie, Amulya Chevuturi, Peter Cook, Nick Klingaman, Christopher E. HollowayAbstract:Abstract. We assess the effect of increasing Horizontal Resolution on simulated precipitation over South America in a climate model. We use atmosphere-only simulations, performed with HadGEM3-GC31 at three Horizontal Resolutions: N96 (~ 130 km, 1.88° × 1.25°), N216 (~ 60 km, 0.83° × 0.56°), and N512 (~25 km, 0.35° × 0.23°). We show that all simulations have systematic biases in annual mean and seasonal mean precipitation over South America (e.g. too wet over the Amazon and too dry in northeast). Increasing Horizontal Resolution improves simulated precipitation over the Andes and north-east Brazil. Over the Andes, improvements from Horizontal Resolution continue to ~ 25 km, while over north-east Brazil, there are no improvements beyond ~ 60 km Resolution. These changes are primarily related to changes in atmospheric dynamics and moisture flux convergence. Over the Amazon basin, precipitation variability increases at higher Resolution. We show that some spatial and temporal features of daily South American precipitation are improved at high Resolution, including the intensity spectra of rainfall. Spatial scales of daily precipitation features are also better simulated, suggesting that higher Resolution may improve the representation of South American mesoscale convective systems.
