Simulation of salinity variability and the related freshwater flux forcing in the tropical Pacific: An evaluation using the Beijing normal university earth system model (BNU-ESM)

2015 ◽  
Vol 32 (11) ◽  
pp. 1551-1564 ◽  
Author(s):  
Hai Zhi ◽  
Rong-Hua Zhang ◽  
Pengfei Lin ◽  
Lanning Wang
Keyword(s):  
Tropical Pacific ◽  
Earth System Model ◽  
System Model ◽  
Freshwater Flux ◽  
Earth System ◽  
Salinity Variability ◽  
Normal University ◽  
The Tropical Pacific

Impact of chlorophyll bias on the tropical Pacific mean climate in an earth system model

2017 ◽  
Vol 51 (7-8) ◽  
pp. 2681-2694 ◽  
Author(s):  
Hyung-Gyu Lim ◽  
Jong-Yeon Park ◽  
Jong-Seong Kug
Keyword(s):  
Tropical Pacific ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Mean Climate ◽  
The Tropical Pacific

scholarly journals Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model

2012 ◽  
Vol 9 (3) ◽  
pp. 1159-1172 ◽  
Author(s):  
A. Gnanadesikan ◽  
J. P. Dunne ◽  
J. John
Keyword(s):  
Global Warming ◽  
Dissolved Oxygen ◽  
Lateral Diffusion ◽  
Earth System Model ◽  
System Model ◽  
Oxygen Solubility ◽  
Earth System ◽  
Eddy Transport ◽  
Term Analysis ◽  
The Tropical Pacific

Abstract. Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic) waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters.

scholarly journals El Niño–Like Physical and Biogeochemical Ocean Response to Tropical Eruptions

2019 ◽  
Vol 32 (9) ◽  
pp. 2627-2649 ◽  
Author(s):  
Yassir A. Eddebbar ◽  
Keith B. Rodgers ◽  
Matthew C. Long ◽  
Aneesh C. Subramanian ◽  
Shang-Ping Xie ◽  
...  
Keyword(s):  
El Niño ◽  
El Nino ◽  
Tropical Pacific ◽  
Earth System Model ◽  
Global Climate Models ◽  
System Model ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Earth System ◽  
Surface Cooling ◽  
Volcanic Forcing

AbstractThe oceanic response to recent tropical eruptions is examined in Large Ensemble (LE) experiments from two fully coupled global climate models, the Community Earth System Model (CESM) and the Geophysical Fluid Dynamics Laboratory Earth System Model (ESM2M), each forced by a distinct volcanic forcing dataset. Following the simulated eruptions of Agung, El Chichón, and Pinatubo, the ocean loses heat and gains oxygen and carbon, in general agreement with available observations. In both models, substantial global surface cooling is accompanied by El Niño–like equatorial Pacific surface warming a year after the volcanic forcing peaks. A mechanistic analysis of the CESM and ESM2M responses to Pinatubo identifies remote wind forcing from the western Pacific as a major driver of this El Niño–like response. Following eruption, faster cooling over the Maritime Continent than adjacent oceans suppresses convection and leads to persistent westerly wind anomalies over the western tropical Pacific. These wind anomalies excite equatorial downwelling Kelvin waves and the upwelling of warm subsurface anomalies in the eastern Pacific, promoting the development of El Niño conditions through Bjerknes feedbacks a year after eruption. This El Niño–like response drives further ocean heat loss through enhanced equatorial cloud albedo, and dominates global carbon uptake as upwelling of carbon-rich waters is suppressed in the tropical Pacific. Oxygen uptake occurs primarily at high latitudes, where surface cooling intensifies the ventilation of subtropical thermocline waters. These volcanically forced ocean responses are large enough to contribute to the observed decadal variability in oceanic heat, carbon, and oxygen.

Ice-shelf Basal Melt Rates in the Energy Exascale Earth System Model (E3SM)

2021 ◽  
Author(s):  
Darin Comeau ◽  
Xylar Asay-Davis ◽  
Carolyn Begeman ◽  
Matthew Hoffman ◽  
Wuyin Lin ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ice Sheet ◽  
High Sensitivity ◽  
Ocean Model ◽  
Earth System Model ◽  
System Model ◽  
Freshwater Flux ◽  
Earth System ◽  
Ice Shelf ◽  
The Antarctic

<p>The processes responsible for freshwater flux from the Antarctic Ice Sheet (AIS) -- ice-shelf basal melting and iceberg calving -- are generally poorly represented in current Earth System Models (ESMs). Here, we document the first effort to date at simulating the ocean circulation and exchanges of heat and freshwater within ice-shelf cavities in a coupled ESM, the Department of Energy's Energy Exascale Earth System Model (E3SM). As a step towards full ice-sheet coupling, we implemented static Antarctic ice-shelf cavities and the ability to calculate ice-shelf basal melt rates from the heat and freshwater fluxes computed by the ocean model. In addition, we added the capability to prescribe forcing from iceberg melt, allowing us to realistically represent the other dominant mass loss process from the AIS. In global, low resolution (i.e., non-eddying ocean) simulations, we find high sensitivity of modeled ocean/ice shelf interactions to the ocean state, which can result in a tipping point to high melt regimes under certain ice shelves, presenting a significant challenge to representing the ocean/ice shelf system in a coupled ESM. We show that inclusion of a spatially dependent parameterization of eddy-induced transport reduces biases in water mass properties on the Antarctic continental shelf. With these improvements, E3SM produces realistic and stable ice-shelf basal melt rates across the continent under pre-industrial climate forcing. We also show preliminary results using an ocean/sea-ice grid that makes use of E3SM’s regional-refinement capability, where increased resolution (down to 12km) is placed in the Southern Ocean around Antarctica, bypassing the need for parameterization of eddy-induced transport in this region. The accurate representation of these processes within a coupled ESM is an important step towards reducing uncertainties in projections of the Antarctic response to climate change and Antarctica's contribution to global sea-level rise.</p>

scholarly journals Description and basic evaluation of Beijing Normal University Earth System Model (BNU-ESM) version 1

2014 ◽  
Vol 7 (5) ◽  
pp. 2039-2064 ◽  
Author(s):  
D. Ji ◽  
L. Wang ◽  
J. Feng ◽  
Q. Wu ◽  
H. Cheng ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Climate Model ◽  
Southern Oscillation ◽  
Surface Air Temperature ◽  
Earth System Model ◽  
Meridional Overturning Circulation ◽  
System Model ◽  
Global Ocean ◽  
Earth System ◽  
Normal University

Abstract. An earth system model has been developed at Beijing Normal University (Beijing Normal University Earth System Model, BNU-ESM); the model is based on several widely evaluated climate model components and is used to study mechanisms of ocean-atmosphere interactions, natural climate variability and carbon-climate feedbacks at interannual to interdecadal time scales. In this paper, the model structure and individual components are described briefly. Further, results for the CMIP5 (Coupled Model Intercomparison Project phase 5) pre-industrial control and historical simulations are presented to demonstrate the model's performance in terms of the mean model state and the internal variability. It is illustrated that BNU-ESM can simulate many observed features of the earth climate system, such as the climatological annual cycle of surface-air temperature and precipitation, annual cycle of tropical Pacific sea surface temperature (SST), the overall patterns and positions of cells in global ocean meridional overturning circulation. For example, the El Niño-Southern Oscillation (ENSO) simulated in BNU-ESM exhibits an irregular oscillation between 2 and 5 years with the seasonal phase locking feature of ENSO. Important biases with regard to observations are presented and discussed, including warm SST discrepancies in the major upwelling regions, an equatorward drift of midlatitude westerly wind bands, and tropical precipitation bias over the ocean that is related to the double Intertropical Convergence Zone (ITCZ).

scholarly journals Description and basic evaluation of BNU-ESM version 1

2014 ◽  
Vol 7 (2) ◽  
pp. 1601-1647 ◽  
Author(s):  
D. Ji ◽  
L. Wang ◽  
J. Feng ◽  
Q. Wu ◽  
H. Cheng ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Climate Model ◽  
Southern Oscillation ◽  
Surface Air Temperature ◽  
Earth System Model ◽  
Meridional Overturning Circulation ◽  
System Model ◽  
Global Ocean ◽  
Earth System ◽  
Normal University

Abstract. An earth system model has been developed at Beijing Normal University (Beijing Normal University Earth System Model, BNU-ESM); the model is based on several widely evaluated climate model components and is used to study mechanisms of ocean–atmosphere interactions, natural climate variability and carbon-climate feedbacks at interannual to interdecadal time scales. In this paper, the model structure and individual components are described briefly. Further, results for the CMIP5 (Coupled Model Intercomparison Project phase 5) pre-industrial control and historical simulations are presented to demonstrate the model's performance in terms of the mean model state and the internal variability. It is illustrated that BNU-ESM can simulate many observed features of the earth climate system, such as the climatological annual cycle of surface air temperature and precipitation, annual cycle of tropical Pacific sea surface temperature (SST), the overall patterns and positions of cells in global ocean meridional overturning circulation. For example, the El Niño-Southern Oscillation (ENSO) simulated in BNU-ESM exhibits an irregular oscillation between 2 and 5 years with the seasonal phase locking feature of ENSO. Important biases with regard to observations are presented and discussed, including warm SST discrepancies in the major upwelling regions, an equatorward drift of midlatitude westerly wind bands, and tropical precipitation bias over the ocean that is related to the double Intertropical Convergence Zone (ITCZ).

Sensitivity of ENSO variability to Pacific freshwater flux adjustment in the Community Earth System Model

2014 ◽  
Vol 31 (5) ◽  
pp. 1009-1021 ◽  
Author(s):  
Xianbiao Kang ◽  
Ronghui Huang ◽  
Zhanggui Wang ◽  
Rong-Hua Zhang
Keyword(s):  
Earth System Model ◽  
System Model ◽  
Freshwater Flux ◽  
Earth System ◽  
Enso Variability ◽  
Community Earth System Model ◽  
Flux Adjustment

Korea Institute of Ocean Science and Technology Earth System Model and Its Simulation Characteristics

2021 ◽  
Author(s):  
Gyundo Pak ◽  
Yign Noh ◽  
Myong-In Lee ◽  
Sang-Wook Yeh ◽  
Daehyun Kim ◽  
...  
Keyword(s):  
Science And Technology ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Ocean Science
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