scholarly journals Improving climate model simulation of tropical Atlantic sea surface temperature: The importance of enhanced vertical atmosphere model resolution

2015 ◽  
Vol 42 (7) ◽  
pp. 2401-2408 ◽  
Author(s):  
Jan Harlaß ◽  
Mojib Latif ◽  
Wonsun Park
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Model Simulation ◽  
Sea Surface ◽  
Tropical Atlantic ◽  
Model Resolution ◽  
Climate Model Simulation ◽  
Atmosphere Model

Local and remote causes of the equatorial Pacific cold sea surface temperature bias in the Kiel Climate Model

2020 ◽  
Author(s):  
Yuming Zhang ◽  
Tobias Bayr ◽  
Mojib Latif ◽  
Zhaoyang Song ◽  
Wonsun Park ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Ocean Circulation ◽  
Climate Model ◽  
Coupled Model ◽  
Equatorial Pacific ◽  
Ocean Dynamics ◽  
Sea Surface ◽  
Sst Bias ◽  
Atmosphere Model

<p>We investigate the origin of the equatorial Pacific cold sea surface temperature (SST) bias and its link to wind biases, local and remote, in the Kiel Climate Model (KCM) with dedicated coupled and stand-alone atmosphere model experiments. In the coupled experiments, the National Centers for Environmental Prediction Climate Forecast System Reanalysis (NCEP/CFSR) wind stress is prescribed over four different spatial domains: globally, over the equatorial Pacific (EP), the northern Pacific (NP) and southern Pacific (SP). The corresponding cold SST bias over the equatorial Pacific is reduced by 94%, 48%, 11% and 22%, respectively. Thus, the equatorial Pacific SST bias is mainly attributed to the wind bias over the EP region, with small but not negligible contributions from the SP and NP regions. Biases in the ocean dynamics cause the EP SST bias, while the atmospheric thermodynamics counteract it.</p><p>To examine the origin of wind biases, we force the atmospheric component of the KCM in stand-alone mode by observed SSTs and simulated SSTs from the coupled experiments with the KCM. The results show that wind biases over the EP, NP and SP regions are initially generated in the atmosphere model and further enhanced by the biased SST in the coupled model.</p><p>We conclude that the cold SST bias over the equatorial Pacific originates from biases in the ocean circulation that are forced by the biased surface winds over the EP, NP and SP regions. On the other hand, the cold equatorial Pacific SST bias amplifies the wind biases over the EP, NP and SP regions, which in turn enhances the cold SST bias by ocean-atmosphere coupling.</p>

scholarly journals Free and Forced Variability of the Tropical Atlantic Ocean: Role of the Wind–Evaporation–Sea Surface Temperature Feedback

2010 ◽  
Vol 23 (22) ◽  
pp. 5958-5977 ◽  
Author(s):  
Salil Mahajan ◽  
R. Saravanan ◽  
Ping Chang
Keyword(s):  
Atlantic Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Coupled Model ◽  
Sea Surface ◽  
Tropical Atlantic ◽  
Wes Feedback ◽  
Meridional Mode

Abstract The role of the wind–evaporation–sea surface temperature (WES) feedback in the low-frequency natural variability of the tropical Atlantic is studied using an atmospheric global climate model—the NCAR Community Climate Model, version 3 (CCM3)—thermodynamically coupled to a slab ocean model (SOM). The coupled model is modified to suppress the WES feedback and is compared to a control run. Singular value decomposition (SVD) analysis over the tropical Atlantic reveals that the coupled meridional mode of the Atlantic Ocean is amplified in the presence of the WES feedback. In its absence, the meridional mode still exists, but with a weaker amplitude. A feedback mechanism that involves the near-surface specific humidity is proposed to sustain the weaker Atlantic meridional mode in the absence of the WES feedback. Similar analysis of coupled model integrations when forced with an artificial El Niño–Southern Oscillation (ENSO)-like SST cycle in the Pacific reveals that in the presence of the WES feedback, the meridional mode is the preferred mode of response of the tropical Atlantic to ENSO forcing. In the absence of the WES feedback, the tropical Atlantic response is unlike the meridional mode and the effects of tropospheric warming and subsidence dominate. Regression analysis over the tropical Atlantic reveals that the meridional mode response to ENSO peaks in the spring and begins to decay in the fall in the coupled model in the presence of the WES feedback. The WES feedback also appears to be responsible for the northward migration of the ITCZ during ENSO events.

Oligocene sea-surface temperature gradients in the Southern Ocean related to Tasmanian Gateway widening: New TEX86 paleothermometry, dinoflagellate cyst data and climate model comparisons

2021 ◽  
Author(s):  
Frida Hoem ◽  
Suning Hou ◽  
Matthew Huber ◽  
Francesca Sangiorgi ◽  
Henk Brinkhuis ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Temperature Gradients ◽  
Ocean Currents ◽  
Sea Surface ◽  
Dinoflagellate Cyst ◽  
Frontal Systems ◽  
Dsdp Site

<p>The opening of the Tasmanian Gateway during the Eocene and further deepening in the Oligocene is hypothesized to have reorganized ocean currents, preconditioning the Antarctic Circumpolar Current (ACC) to evolve into place. However, fundamental questions still remain on the past Southern Ocean structure. We here present reconstructions of latitudinal temperature gradients and the position of ocean frontal systems in the Australian sector of the Southern Ocean during the Oligocene. We generated new sea surface temperature (SST) and dinoflagellate cyst data from the West Tasman margin, ODP Site 1168. We compare these with other records around the Tasmanian Gateway, and with climate model simulations to analyze the paleoceanographic evolution during the Oligocene. The novel organic biomarker TEX<sub>86</sub>- SSTs from ODP Site 1168, range between 19.6 – 27.9°C (± 5.2°C, using the linear calibration by Kim et al., 2010), supported by temperate and open ocean dinoflagellate cyst assemblages. The data compilation, including existing TEX<sub>86</sub>-based SSTs from ODP Site 1172 in the Southwest Pacific Ocean, DSDP Site 274 offshore Cape Adare, DSDP Site 269 and IODP Site U1356 offshore the Wilkes Land Margin and terrestrial temperature proxy records from the Cape Roberts Project (CRP) on the Ross Sea continental shelf, show synchronous variability in temperature evolution between Antarctic and Australian sectors of the Southern Ocean. The SST gradients are around 10°C latitudinally across the Tasmanian Gateway throughout the early Oligocene, and increasing in the Late Oligocene. This increase can be explained by polar amplification/cooling, tectonic drift, strengthening of atmospheric currents and ocean currents. We suggest that the progressive cooling of Antarctica and the absence of mid-latitude cooling strengthened the westerly winds, which in turn could drive an intensification of the ACC and strengthening of Southern Ocean frontal systems.</p>

scholarly journals The impact of climate model sea surface temperature biases on tropical cyclone simulations

2018 ◽  
Vol 53 (1-2) ◽  
pp. 173-192 ◽  
Author(s):  
Wei-Ching Hsu ◽  
Christina M. Patricola ◽  
Ping Chang
Keyword(s):  
Tropical Cyclone ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Sea Surface ◽  
The Impact

Ozone and temperature response of a chemistry climate model to the solar cycle and sea surface temperature

2010 ◽  
Vol 115 ◽  
Author(s):  
Yousuke Yamashita ◽  
Kei Sakamoto ◽  
Hideharu Akiyoshi ◽  
Masaaki Takahashi ◽  
Tatsuya Nagashima ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Climate Model ◽  
Temperature Response ◽  
Sea Surface
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