Surface waves have a considerable effect on vertical mixing in the upper ocean.In the past two decades,the vertical mixing induced through nonbreaking surface waves has been used in ocean and climate models to improve...Surface waves have a considerable effect on vertical mixing in the upper ocean.In the past two decades,the vertical mixing induced through nonbreaking surface waves has been used in ocean and climate models to improve the simulation of the upper ocean.Thus far,several nonbreaking wave-induced mixing parameterization schemes have been proposed;however,no quantitative comparison has been performed among them.In this paper,a one-dimensional ocean model was used to compare the performances of five schemes,including those of Qiao et al.(Q),Hu and Wang(HW),Huang and Qiao(HQ),Pleskachevsky et al.(P),and Ghantous and Babanin(GB).Similar to previous studies,all of these schemes can decrease the simulated sea surface temperature(SST),increase the subsurface temperature,and deepen the mixed layer,thereby alleviating the common thermal deviation problem of the ocean model for upper ocean simulation.Among these schemes,the HQ scheme exhibited the weakest wave-induced mixing effect,and the HW scheme exhibited the strongest effect;the other three schemes exhibited roughly the same effect.In particular,the Q and P schemes exhibited nearly the same effect.In the simulation based on observations from the Ocean Weather Station Papa,the HQ scheme exhibited the best performance,followed by the Q scheme.In the experiment with the HQ scheme,the root-mean-square deviation of the simulated SST from the observations was 0.43℃,and the mixed layer depth(MLD)was 2.0 m.As a contrast,the deviations of the SST and MLD reached 1.25℃ and 8.4 m,respectively,in the experiment without wave-induced mixing.展开更多
Future potential sea level change in the South China Sea （SCS） is estimated by using 24 CMIP5 models under different representative concentration pathway （RCP） scenarios. By the end of the 21st century （2081–210...Future potential sea level change in the South China Sea （SCS） is estimated by using 24 CMIP5 models under different representative concentration pathway （RCP） scenarios. By the end of the 21st century （2081–2100 relative to 1986–2005）, the multimodel ensemble mean dynamic sea level （DSL） is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise （SLR） of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level （SSL） rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21st century, compared with the north and southwest shelves.展开更多
The influence of the nonbreaking surface wave-induced mixing under the mixed layer on the oceanic cir- culation was investigated using an isopycnal-coordinate oceanic circulation model. The effect of the wave- induced...The influence of the nonbreaking surface wave-induced mixing under the mixed layer on the oceanic cir- culation was investigated using an isopycnal-coordinate oceanic circulation model. The effect of the wave- induced mixing within the mixed layer was eliminated via a bulk mixed layer model. The results show that the wave-induced mixing can penetrate through the mixed layer and into the oceanic interior. The wave- induced mixing under the mixed layer has an important effect on the distribution of temperature of the upper ocean at middle and high latitudes in summer, especially the structure of the seasonal thermocline. Moreover, the wave-induced mixing can affect the oceanic circulation, such as western boundary currents and the North Equatorial Currents through changes of sea surface height associated with the variation of the thermal structure of the upper ocean.展开更多
Compared with observations,the simulated upper ocean heat content(OHC)determined from climate models shows an underestimation bias.The simulation bias of the average annual water temperature in the upper 300 m is 0.2...Compared with observations,the simulated upper ocean heat content(OHC)determined from climate models shows an underestimation bias.The simulation bias of the average annual water temperature in the upper 300 m is 0.2℃lower than the observational results.The results from our two numerical experiments,using a CMIP5 model,show that the non-breaking surface wave-induced vertical mixing can reduce this bias.The enhanced vertical mixing increases the OHC in the global upper ocean(65°S–65°N).Using non-breaking surface wave-induced vertical mixing reduced the disparity by 30%to 0.14℃.The heat content increase is not directly induced by air-sea heat fluxes during the simulation period,but is the legacy of temperature increases in the first 150 years.During this period,additional vertical mixing was initially included in the climate model.The non-breaking surface wave-induced vertical mixing improves the OHC by increasing the air-sea heat fluxes in the first 150 years.This increase in air-sea heat fluxes warms the upper ocean by 0.05–0.06℃.The results show that the incorporation of vertical mixing induced by nonbreaking surface waves in our experiments can improve the simulation of OHC in the global upper ocean.展开更多
Insufficient vertical mixing in the upper ocean during summer is a common problem of oceanic circulation and climate models.The turbulence associated with non-breaking waves is widely believed to effectively solve thi...Insufficient vertical mixing in the upper ocean during summer is a common problem of oceanic circulation and climate models.The turbulence associated with non-breaking waves is widely believed to effectively solve this problem.In many studies,non-breaking surface wave processes are attributed to the effects of Langmuir circulations(LCs).In the present work,the influences of LCs on the upper-ocean thermal structure are examined by using one-and three-dimensional ocean circulation,as well as climate,models.The results indicated that the effect of vertical mixing enhanced by LCs is limited to the upper ocean.The models evaluated,including those considering LC effects alone and the combined effects of LCs and wave breaking,failed to produce a reasonable summertime thermocline,resulting in a large cold bias in the subsurface layer.Therefore,while they can slightly reduce the biases of mixed layer depths and sea surface temperatures in models,LCs are insufficient to solve the problem of insufficient vertical mixing.Moreover,restriction of non-breaking surface wave-induced processes in LCs may be questionable.展开更多
The influence of horizontal mixing on the thermal structure of the equatorial Pacific Ocean is examined based on a sigma coordinate model. In general, the distributions of the temperature and currents simulated by the...The influence of horizontal mixing on the thermal structure of the equatorial Pacific Ocean is examined based on a sigma coordinate model. In general, the distributions of the temperature and currents simulated by the sigma coordinate model are very close to the climatology. However, the simulated thermocline along the equator is slightly diffusive so that there is a cold bias above the main thermocline, while there is a warm bias under the main thermocline. Both horizontal diffusivity and viscosity have important effects on the upper thermal structure in the equatorial Pacific Ocean, while their detailed dynamics are different. Horizontal diffusivity affects the thermal structure in the upper ocean mainly through regulating the vertical diffusivity, while the horizontal viscosity does mainly through regulating directly the circulate system. A large horizontal diffusivity or a small horizontal viscosity can be in favor of simulating a more realistically thermal structure in the equatorial Pacific Ocean.展开更多
基金supported by the Laoshan Laboratory(No.LSKJ202201600)the National Key Research and Development Program of China(No.2022YFC2808304).
文摘Surface waves have a considerable effect on vertical mixing in the upper ocean.In the past two decades,the vertical mixing induced through nonbreaking surface waves has been used in ocean and climate models to improve the simulation of the upper ocean.Thus far,several nonbreaking wave-induced mixing parameterization schemes have been proposed;however,no quantitative comparison has been performed among them.In this paper,a one-dimensional ocean model was used to compare the performances of five schemes,including those of Qiao et al.(Q),Hu and Wang(HW),Huang and Qiao(HQ),Pleskachevsky et al.(P),and Ghantous and Babanin(GB).Similar to previous studies,all of these schemes can decrease the simulated sea surface temperature(SST),increase the subsurface temperature,and deepen the mixed layer,thereby alleviating the common thermal deviation problem of the ocean model for upper ocean simulation.Among these schemes,the HQ scheme exhibited the weakest wave-induced mixing effect,and the HW scheme exhibited the strongest effect;the other three schemes exhibited roughly the same effect.In particular,the Q and P schemes exhibited nearly the same effect.In the simulation based on observations from the Ocean Weather Station Papa,the HQ scheme exhibited the best performance,followed by the Q scheme.In the experiment with the HQ scheme,the root-mean-square deviation of the simulated SST from the observations was 0.43℃,and the mixed layer depth(MLD)was 2.0 m.As a contrast,the deviations of the SST and MLD reached 1.25℃ and 8.4 m,respectively,in the experiment without wave-induced mixing.
基金The National Basic Research Program(973 Program)of China under contract No.2010CB950501the National Natural Science Foundation of China under contract No.41276035the National Natural Science Foundation of China–Shandong Province Joint Fund of Marine Science Research Centers under contract No.U1406404
文摘Future potential sea level change in the South China Sea （SCS） is estimated by using 24 CMIP5 models under different representative concentration pathway （RCP） scenarios. By the end of the 21st century （2081–2100 relative to 1986–2005）, the multimodel ensemble mean dynamic sea level （DSL） is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise （SLR） of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level （SSL） rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21st century, compared with the north and southwest shelves.
基金Basic Scientific Funds for National Public Research Institues of China under contract No.GY02-2009G24Public Science and Technology Research Funds Projects of Ocean under contract No.201105019the Sino-US International Cooperation Project under contract No.S2011GR0348
文摘The influence of the nonbreaking surface wave-induced mixing under the mixed layer on the oceanic cir- culation was investigated using an isopycnal-coordinate oceanic circulation model. The effect of the wave- induced mixing within the mixed layer was eliminated via a bulk mixed layer model. The results show that the wave-induced mixing can penetrate through the mixed layer and into the oceanic interior. The wave- induced mixing under the mixed layer has an important effect on the distribution of temperature of the upper ocean at middle and high latitudes in summer, especially the structure of the seasonal thermocline. Moreover, the wave-induced mixing can affect the oceanic circulation, such as western boundary currents and the North Equatorial Currents through changes of sea surface height associated with the variation of the thermal structure of the upper ocean.
基金Supported by the International Cooperation Project on the China-Australia Research Centre for Maritime Engineering of Ministry of Science and Technology,China(No.2016YFE0101400)the Basic Scientific Fund for National Public Research Institutes of China(No.2018S03)+4 种基金the National Natural Science Foundation of China(Nos.41821004,41776038)the NSFC-Shandong Joint Fund for Marine Science Research Centers(No.U1606405)the International Cooperation Project of Indo-Pacific Ocean Environment Variation and Air-Sea Interaction(No.GASI-IPOVAI-05)the IOC/WESTPAC OFS Project,the Ao Shan Talents Cultivation Excellent Scholar Program Supported by Qingdao National Laboratory for Marine Science and Technology(No.2017ASTCP-ES04)the China-Korea Cooperation Project on the Prediction of North-West Pacific Climate Change
文摘Compared with observations,the simulated upper ocean heat content(OHC)determined from climate models shows an underestimation bias.The simulation bias of the average annual water temperature in the upper 300 m is 0.2℃lower than the observational results.The results from our two numerical experiments,using a CMIP5 model,show that the non-breaking surface wave-induced vertical mixing can reduce this bias.The enhanced vertical mixing increases the OHC in the global upper ocean(65°S–65°N).Using non-breaking surface wave-induced vertical mixing reduced the disparity by 30%to 0.14℃.The heat content increase is not directly induced by air-sea heat fluxes during the simulation period,but is the legacy of temperature increases in the first 150 years.During this period,additional vertical mixing was initially included in the climate model.The non-breaking surface wave-induced vertical mixing improves the OHC by increasing the air-sea heat fluxes in the first 150 years.This increase in air-sea heat fluxes warms the upper ocean by 0.05–0.06℃.The results show that the incorporation of vertical mixing induced by nonbreaking surface waves in our experiments can improve the simulation of OHC in the global upper ocean.
基金the National Key Research and Development Program of China(No.2017YFC1404000)the Basic Scientific Fund for National Public Research Institutes of China(No.2018S03)+1 种基金the National Natural Science Foundation of China(Nos.41776038 and 41376036)Dr.Fangli Qiao was supported by the Natural Science Foundation of China(Nos.41821004).
文摘Insufficient vertical mixing in the upper ocean during summer is a common problem of oceanic circulation and climate models.The turbulence associated with non-breaking waves is widely believed to effectively solve this problem.In many studies,non-breaking surface wave processes are attributed to the effects of Langmuir circulations(LCs).In the present work,the influences of LCs on the upper-ocean thermal structure are examined by using one-and three-dimensional ocean circulation,as well as climate,models.The results indicated that the effect of vertical mixing enhanced by LCs is limited to the upper ocean.The models evaluated,including those considering LC effects alone and the combined effects of LCs and wave breaking,failed to produce a reasonable summertime thermocline,resulting in a large cold bias in the subsurface layer.Therefore,while they can slightly reduce the biases of mixed layer depths and sea surface temperatures in models,LCs are insufficient to solve the problem of insufficient vertical mixing.Moreover,restriction of non-breaking surface wave-induced processes in LCs may be questionable.
基金The National Natural Science Foundation of China under contract Nos 40806017 and 40730842the National Basic Research Program (973 Program) of China under contract No.2010CB950500
文摘The influence of horizontal mixing on the thermal structure of the equatorial Pacific Ocean is examined based on a sigma coordinate model. In general, the distributions of the temperature and currents simulated by the sigma coordinate model are very close to the climatology. However, the simulated thermocline along the equator is slightly diffusive so that there is a cold bias above the main thermocline, while there is a warm bias under the main thermocline. Both horizontal diffusivity and viscosity have important effects on the upper thermal structure in the equatorial Pacific Ocean, while their detailed dynamics are different. Horizontal diffusivity affects the thermal structure in the upper ocean mainly through regulating the vertical diffusivity, while the horizontal viscosity does mainly through regulating directly the circulate system. A large horizontal diffusivity or a small horizontal viscosity can be in favor of simulating a more realistically thermal structure in the equatorial Pacific Ocean.
