检索结果-南通市图书馆

同方期刊数据库

Mechanisms of shelf-break frontogenesis

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2008年第Z1期27卷 9-20页

作者： chen dake State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012 China Lamont-Doherty Earth Observatory of Columbia University Palisades New York USA

The shelf-break front is an omnipresent phenomenon in coastal oceans all over the world, but there is still no definitive explanation for the genesis of such a front. It is possible that different mechanisms are operative at different times and locations, but all of them should have something to do with the sharp change of bottom topography near the shelf-break. A couple of recently proposed mechanisms of shelf-break frontogenesis are dicussed. One of them invokes a flow convergence produced by local air-sea interaction over sloping topography, whereas the other relies on the depth dependence of wind-induced shear dispersion. These novel ideas are based on new observational evidences and previous theoretical studies, and they are demonstrated here using an idealized ocean-atmosphere coupled model and a stand-alone ocean model. The air-sea interaction mechanism seems plausible for the shelf-break front in the East China Sea, and the shear dispersion mechanism is likely to be applicable to the shelf-break front off the northeastern United States.

关键词： shelf-break front air-sea interaction shear dispersion

The ocean's role in climate variability

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2008年第Z1期27卷 1-8页

作者： chen dake State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012 China Lamont - Doherty Earth Observatory of Columbia University Palisades New York USA

Because of its vast volume and heat capacity, the ocean contains most of the memory of the earth's ocean-atmosphere coupled system. It has been suggested that the ocean may delay global warming by absorbing large amounts of heat, that it may cause abrupt climate change due to its disrupted thermohaline circulation, and that it may set the time-scales for various climate oscillations. Although the slow pace and persistence of oceanic variations give hope to long-range prediction, there still exist large uncertainties in climate predictability. Presently available observations and models are generally inadequate for studying and predicting long-term climate changes. However, some short-term fluctuations such as ENSO have been well studied and shown to be highly predictable even with simplified models.

关键词： ocean climate variability predictability.

Polar climate system modeling in China: Recent progress and future challenges

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2019年第7期62卷 1076-1091页

作者： Zhaomin WANG dake chen College of Oceanography Hohai University International Polar Environment Research Laboratory Hohai University State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography

The first fully coupled atmosphere-ocean-sea ice model developed in China was released in the mid-1990s. Since then, significant advances in climate system model developments have been achieved by improving the representations of major physical processes, increasing resolutions, and including an ice-shelf component. There have also been many modeling studies in China on the polar climate system, including weather and sea-ice numerical forecasts to meet the national needs of polar scientific expeditions, assessments of the state-of-the-art coupled model performance, and process-oriented studies. Future model developments and modeling activities will need to address several big scientific questions originating from the polar climate system: i) How will polar ice mass balance evolve and affect global sea level? ii) How can we properly simulate openocean deep convection and quantify its role in driving the lower branch of the global overturning circulation? iii) How are Arctic and Antarctic connected and what caused the contrasting sea ice trends in the two polar regions over the last decades? To address these questions, polar climate system modelers will need to analyze extended observational datasets on a global scale and work together with other polar researchers to develop a more comprehensive and sustainable observation system in the polar regions.

关键词： Polar climate system Modeling Progress Challenges

Spatiotemporal modes of global sea surface temperature variability

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2017年第3期60卷 508-516页

作者： ZHANG XiangMing chen chen LIAN Tao chen dake State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyHangzhou 310012China Lamont-Doherty Earth Observatory of Columbia University New York 10027USA

This study identifies the salient global modes of sea surface temperature variability based on 145 years of HadlSST *** the traditional mode identification by EOF analysis,a combination of wavelet and EOF analysis is used to extract the leading modes at distinct time *** spatial patterns of some well-known regional modes are recovered,with the global connection and frequency content of these modes being *** analysis indicates that,in terms of global influence,the Pacific Ocean is the major player,and the tropical Pacific is the center of action on various time *** Atlantic Ocean has its own outstanding modes,but their global impacts are not as strong as those from the *** Indian Ocean generally shows a passive response to the Pacific,with a basin-wide pattern in the *** some preliminary theoretical attempts,how to elucidate the dynamics underlying the global modes of sea surface temperature variability is still an open question.

关键词： Global mode Wavelet EOF

Interaction of western-Pacific tropical cyclones with El Nio diversity

在线全文

学校读者我要写书评

暂无评论

National Science Review 2018年第6期5卷 803-804页

作者： dake chen Tao Lian State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography Lamont-Doherty Earth Observatory of Columbia University

Tropical cyclones (TCs) and El NioSouthern Oscillation (ENSO) are both high-impact phenomena, and their interaction is a subject of great scientific interest and practical importance. It is now widely accepted that ... 详细信息

关键词： El Interaction of western-Pacific tropical cyclones with El Ni o diversity

Genesis of the 2014–2016 El Nio events

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2017年第9期60卷 1589-1600页

作者： LIAN Tao chen dake TANG YouMin State Key Lab of Satellite Ocean Environment Dynamics Second Institute of Oceanography Environmental Science and Engineering University of Northern British Columbia

The 2015/2016 El Nio was one of the strongest El Nio events in history, and this strong event was preceded by a weak El Nio in 2014. This study systematically analyzed the dynamical processes responsible for the genesis of these events. It was found that the weak 2014 El Nio had two warming phases, the spring-summer warming was produced by zonal advection and downwelling Kelvin waves driven by westerly wind bursts(WWBs), and the autumn-winter warming was produced by meridional advection, surface heating as well as downwelling Kelvin waves. The 2015/2016 extreme El Nio, on the other hand, was primarily a result of sustained zonal advection and downwelling Kelvin waves driven by a series of WWBs, with enhancement from the Bjerknes positive feedback. The vast difference between these two El Nio events mainly came from the different amount of WWBs in 2014 and 2015. As compared to the 1982/1983 and 1997/1998 extreme El Nio events, the 2015/2016 El Nio exhibited some distinctive characteristics in its genesis and spatial pattern. We need to include the effects of WWBs to the theoretical framework of El Nio to explain these characteristics, and to improve our understanding and prediction of El Nio.

关键词： El Nio WWBs Upper ocean heat content

Upper ocean response to tropical cyclone wind forcing: A case study of typhoon Rammasun(2008)

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2015年第9期58卷 1623-1632页

作者： PEI YuHua ZHANG RongHua chen dake College of Physical and Environmental Oceanography Ocean University of China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyState Oceanic Administration Key Laboratory of Ocean Circulation and Waves Institute of Oceanology Chinese Academy of Sciences

The characteristics of the upper ocean response to tropical cyclone wind （TCW） forcing in the northwestern Pacific were in- vestigated using satellite and Argo data, as well as an ocean general circulation model. In particular, a case study was carried out on typhoon Rammasun, which passed through our study area during May 6-13, 2008. It is found that the local response fight under the TCW forcing is characterized by a quick deepening of the surface mixed layer, a strong latent heat loss to the atmosphere, and an intense upwelling near the center of typhoon, leading to a cooling of the oceanic surface layer that persists as a cold wake along the typhoon track. More interestingly, the upper ocean response exhibits a four-layer thermal structure, including a cooling layer near the surface and a warming layer right below, accompanied by another pair of cooling/warming layers in the thermocline. The formation of the surface cooling/warming layers can be readily explained by the strong vertical mixing induced by TCW forcing, while the thermal response in the thermocline is probably a result of the cyclone-driven upwelling and the associated advective processes.

关键词： tropical cyclone wind forcing upper ocean response satellite and Argo data ocean modeling

Roles of different physical processes in upper ocean responses to Typhoon Rammasun(2008)-induced wind forcing

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2019年第4期62卷 684-692页

作者： Yuhua PEI Rong-Hua ZHANG dake chen State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural Resources CAS Key Laboratory of Ocean Circulation and Waves Institute of Oceanology Chinese Academy of Sciences Qingdao National Laboratory for Marine Science and Technology University of Chinese Academy of Sciences

This study investigates the roles of different physical processes in the oceanic response to tropical cyclones(TCs) in the Pacific, using an ocean general circulation model with several numerical experiments. A case study is focused on Typhoon Rammasun, which passed through the northwestern tropical Pacific in May 2008. TC-induced wind stress fields are extracted using a locally-weighted regression(Loess) method from a six-hourly Cross-Calibrated Multi-Platform satellite scatterometer wind product. By comparing model experiments with TC wind forcing being explicitly included or not, the effects of TC on the ocean are isolated in a clean way. The local oceanic response is characterized by a cooling in the surface layer that persists along the typhoon track as a cold wake, and a deepening of the mixed layer(ML). The TC-induced wind can affect the ocean through the momentum effects, the ML processes(the stirring effect on the ML depth), and heat flux(via wind speed), *** of numerical experiments with these different underlying processes explicitly represented or not indicate that vertical mixing and upwelling are dominant processes responsible for surface cooling, while the surface heat flux also plays a nonnegligible role. Specifically, vertical mixing, upwelling and surface heat flux account for respectively ～53%, ～31% and ～16% of the sea surface temperature cooling. However, for the ML response, the vertical mixing and surface heat flux are dominant processes for the ML deepening, while the contribution from upwelling process is negligible. This study provides new insights into how TC-indcued wind forcing affects the ocean by isolating each different individual process in a clear way, which differs from previous direct heat budget analyses.

关键词： Ocean response to typhoon Ocean modeling Vertical mixing The tropical Pacific

The evolving ENSO observing system

在线全文

学校读者我要写书评

暂无评论

National Science Review 2018年第6期5卷 805-807页

作者： dake chen Neville Smith William Kessler State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography

El Nio–Southern Oscillation (ENSO)is by far the most energetic and influential short-term climate variability on our planet, originating from an instability of the large-scale ocean-atmosphere interaction in the tr... 详细信息

关键词： The evolving ENSO observing system TAO