Inter-model variability of projected sea level changes in the western North Pacific in CMIP3 coupled climate models

2012 ◽  
Vol 68 (4) ◽  
pp. 533-543 ◽  
Author(s):  
Masakazu Sueyoshi ◽  
Tamaki Yasuda
Keyword(s):  
Sea Level ◽  
North Pacific ◽  
Western North Pacific ◽  
Climate Models ◽  
Sea Level Changes ◽  
Coupled Climate Models ◽  
Model Variability

scholarly journals Variability of the Western North Pacific Subtropical High in the CMIP5 Coupled Climate Models

Atmosphere ◽  
2016 ◽  
Vol 26 (4) ◽  
pp. 687-696 ◽  
Author(s):  
Eunjin Kim ◽  
MinHo Kwon ◽  
Kang-Jin Lee
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Climate Models ◽  
Subtropical High ◽  
Coupled Climate Models

scholarly journals Interdecadal Baroclinic Sea Level Changes in the North Pacific Based on Historical Ocean Hydrographic Observations

2015 ◽  
Vol 28 (11) ◽  
pp. 4585-4594 ◽  
Author(s):  
Tatsuo Suzuki ◽  
Masayoshi Ishii
Keyword(s):  
Sea Level ◽  
Wind Stress ◽  
North Pacific ◽  
Water Mass ◽  
Mass Density ◽  
Baroclinic Mode ◽  
Sea Level Changes ◽  
The North ◽  
Basin Scale ◽  
The North Pacific

Abstract Using historical ocean hydrographic observations, decadal to multidecadal sea level changes from 1951 to 2007 in the North Pacific were investigated focusing on vertical density structures. Hydrographically, the sea level changes could reflect the following: changes in the depth of the main pycnocline, density gradient changes across the pycnocline, and modification of the water mass density structure within the pycnocline. The first two processes are characterized as the first baroclinic mode. The changes in density stratification across the pycnocline are sufficiently small to maintain the vertical profile of the first baroclinic mode in this analysis period. Therefore, the first mode should represent mainly the dynamical response to the wind stress forcing. Meanwhile, changes in the composite of all modes of order greater than 1 (remaining baroclinic mode) can be attributed to water mass modifications above the pycnocline. The first baroclinic mode is associated with 40–60-yr fluctuations in the subtropical gyre and bidecadal fluctuations of the Kuroshio Extension (KE) in response to basin-scale wind stress changes. In addition to this, the remaining baroclinic mode exhibits strong variability around the recirculation region south of the KE and regions downstream of the KE, accompanied by 40–60-yr and bidecadal fluctuations, respectively. These fluctuations follow spinup/spindown of the subtropical gyre and meridional shifts of the KE shown in the first mode, respectively. A lag correlation analysis suggests that interdecadal sea level changes due to water mass density changes are a secondary consequence of changes in basin-scale wind stress forcing related to the ocean circulation changes associated with the first mode.

scholarly journals Intraseasonal variability of sea level in the Western North Pacific

2021 ◽  
Author(s):  
Haolang Liu ◽  
Xiangbo Feng ◽  
Aifeng Tao ◽  
wei Zhang
Keyword(s):  
Sea Level ◽  
North Pacific ◽  
Western North Pacific ◽  
Intraseasonal Variability

Projected sea-level changes in the marginal seas near China based on dynamical downscaling

2021 ◽  
pp. 1-52
Author(s):  
Yi Jin ◽  
Xuebin Zhang ◽  
John A. Church ◽  
Xianwen Bao
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Climate Models ◽  
Dynamical Downscaling ◽  
Global Climate Models ◽  
Open Boundary ◽  
Open Boundary Conditions ◽  
Sea Level Changes ◽  
Marginal Seas ◽  
The Pacific

AbstractProjections of future sea-level changes are usually based on global climate models (GCMs). However, the changes in shallow coastal regions, like the marginal seas near China, cannot be fully resolved in GCMs. To improve regional sea-level simulations, a high-resolution (~8 km) regional ocean model is set up for the marginal seas near China for both the historical (1994-2015) and future (2079-2100) periods under representative concentration pathways (RCPs) 4.5 and 8.5. The historical ocean simulations are evaluated at different spatiotemporal scales, and the model is then integrated for the future period, driven by projected monthly climatological climate change signals from 8 GCMs individually via both surface and open boundary conditions. The downscaled ocean changes derived by comparing historical and future experiments reveal greater spatial details than those from GCMs, e.g., a low dynamic sea level (DSL) centre of -0.15 m in the middle of the South China Sea (SCS). As a novel test, the downscaled results driven by the ensemble mean forcings are almost identical with the ensemble average results from individually downscaled cases. Forcing of the DSL change and increased cyclonic circulation in the SCS are dominated by the climate change signals from the Pacific, while the DSL change in the East China marginal seas is caused by both local atmosphere forcing and signals from the Pacific. The method of downscaling developed in this study is a useful modelling protocol for adaptation and mitigation planning for future oceanic climate changes.

scholarly journals Tropical Pacific spatial trend patterns in observed sea level: internal variability and/or anthropogenic signature?

2012 ◽  
Vol 8 (2) ◽  
pp. 787-802 ◽  
Author(s):  
B. Meyssignac ◽  
D. Salas y Melia ◽  
M. Becker ◽  
W. Llovel ◽  
A. Cazenave
Keyword(s):  
Sea Level ◽  
Climate Models ◽  
Internal Variability ◽  
Tropical Pacific ◽  
External Forcing ◽  
Spatial Trend ◽  
Trend Pattern ◽  
Coupled Climate Models ◽  
Sea Level Trend ◽  
The Tropical Pacific

Abstract. In this study we focus on the sea level trend pattern observed by satellite altimetry in the tropical Pacific over the 1993–2009 time span (i.e. 17 yr). Our objective is to investigate whether this 17-yr-long trend pattern was different before the altimetry era, what was its spatio-temporal variability and what have been its main drivers. We try to discriminate the respective roles of the internal variability of the climate system and of external forcing factors, in particular anthropogenic emissions (greenhouse gases and aerosols). On the basis of a 2-D past sea level reconstruction over 1950–2009 (based on a combination of observations and ocean modelling) and multi-century control runs (i.e. with constant, preindustrial external forcing) from eight coupled climate models, we have investigated how the observed 17-yr sea level trend pattern evolved during the last decades and centuries, and try to estimate the characteristic time scales of its variability. For that purpose, we have computed sea level trend patterns over successive 17-yr windows (i.e. the length of the altimetry record), both for the 60-yr long reconstructed sea level and the model runs. We find that the 2-D sea level reconstruction shows spatial trend patterns similar to the one observed during the altimetry era. The pattern appears to have fluctuated with time with a characteristic time scale of the order of 25–30 yr. The same behaviour is found in multi-centennial control runs of the coupled climate models. A similar analysis is performed with 20th century coupled climate model runs with complete external forcing (i.e. solar plus volcanic variability and changes in anthropogenic forcing). Results suggest that in the tropical Pacific, sea level trend fluctuations are dominated by the internal variability of the ocean–atmosphere coupled system. While our analysis cannot rule out any influence of anthropogenic forcing, it concludes that the latter effect in that particular region is stillhardly detectable.

scholarly journals Atmospheric circulation changes and their impact on extreme sea levels around Australia

2019 ◽  
Vol 19 (5) ◽  
pp. 1067-1086 ◽  
Author(s):  
Frank Colberg ◽  
Kathleen L. McInnes ◽  
Julian O'Grady ◽  
Ron Hoeke
Keyword(s):  
Sea Level ◽  
Large Scale ◽  
Climate Models ◽  
Tide Gauge ◽  
Austral Summer ◽  
Sea Level Changes ◽  
Sea Level Variability ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
Coastal Sea

Abstract. Projections of sea level rise (SLR) will lead to increasing coastal impacts during extreme sea level events globally; however, there is significant uncertainty around short-term coastal sea level variability and the attendant frequency and severity of extreme sea level events. In this study, we investigate drivers of coastal sea level variability (including extremes) around Australia by means of historical conditions as well as future changes under a high greenhouse gas emissions scenario (RCP 8.5). To do this, a multi-decade hindcast simulation is validated against tide gauge data. The role of tide–surge interaction is assessed and found to have negligible effects on storm surge characteristic heights over most of the coastline. For future projections, 20-year-long simulations are carried out over the time periods 1981–1999 and 2081–2099 using atmospheric forcing from four CMIP5 climate models. Changes in extreme sea levels are apparent, but there are large inter-model differences. On the southern mainland coast all models simulated a southward movement of the subtropical ridge which led to a small reduction in sea level extremes in the hydrodynamic simulations. Sea level changes over the Gulf of Carpentaria in the north are largest and positive during austral summer in two out of the four models. In these models, changes to the northwest monsoon appear to be the cause of the sea level response. These simulations highlight a sensitivity of this semi-enclosed gulf to changes in large-scale dynamics in this region and indicate that further assessment of the potential changes to the northwest monsoon in a larger multi-model ensemble should be investigated, together with the northwest monsoon's effect on extreme sea levels.

scholarly journals Future Change in Tropical Cyclone Activity over the Western North Pacific in CORDEX-East Asia Multi-RCMs Forced by HadGEM2-AO

2019 ◽  
Vol 32 (16) ◽  
pp. 5053-5067 ◽  
Author(s):  
Hyeonjae Lee ◽  
Chun-Sil Jin ◽  
Dong-Hyun Cha ◽  
Minkyu Lee ◽  
Dong-Kyou Lee ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
East Asia ◽  
North Pacific ◽  
Western North Pacific ◽  
Climate Models ◽  
Regional Climate ◽  
Vertical Wind Shear ◽  
Coastal Regions ◽  
The Future ◽  
Cordex East Asia

AbstractFuture changes in tropical cyclone (TC) activity over the western North Pacific (WNP) are analyzed using four regional climate models (RCMs) within the Coordinated Regional Climate Downscaling Experiment (CORDEX) for East Asia. All RCMs are forced by the HadGEM2-AO under the historical and representative concentration pathway (RCP) 8.5 scenarios, and are performed at about 50-km resolution over the CORDEX-East Asia domain. In the historical simulations (1980–2005), multi-RCM ensembles yield realistic climatology for TC tracks and genesis frequency during the TC season (June–November), although they show somewhat systematic biases in simulating TC activity. The future (2024–49) projections indicate an insignificant increase in the total number of TC genesis (+5%), but a significant increase in track density over East Asia coastal regions (+17%). The enhanced TC activity over the East Asia coastal regions is mainly related to vertical wind shear weakened by reduced meridional temperature gradient and increased sea surface temperature (SST) at midlatitudes. The future accumulated cyclone energy (ACE) of total TCs increases significantly (+19%) because individual TCs have a longer lifetime (+6.6%) and stronger maximum wind speed (+4.1%) compared to those in the historical run. In particular, the ACE of TCs passing through 25°N increases by 45.9% in the future climate, indicating that the destructiveness of TCs can be significantly enhanced in the midlatitudes despite the total number of TCs not changing greatly.

Changes in the Past and Projected Western North Pacific Tropical Cyclone Activity in a Warmed Climate

2020 ◽  
Author(s):  
Liang Wu
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Large Scale ◽  
Climate Models ◽  
Rapid Development ◽  
Current Trend ◽  
Coupled Model ◽  
Rcp 8.5 ◽  
Projected Changes

<p><span>Two high-resolution climate models (the HiRAM and MRI-AGCM3.2) are used to simulate present-day western North Pacific (WNP) tropical cyclone (TC) activity and investigate </span><span>the </span><span>projected changes for the late 21<sup>st</sup> century. Compared </span><span>to</span><span>observation</span><span>s</span><span>, the models </span><span>are</span><span> able to realistically simulate many basic features of </span><span>the WNP</span><span> TC activity </span><span>climatolog</span><span>y. Future projections </span><span>with the coupled model inter-comparison project phase 5 (CMIP5) under Representative Concentration Pathway (RCP) 8.5 scenario</span><span> show a tendency for decreases in the number of WNP TCs</span><span>,</span> <span>and of</span><span> increase</span><span>s</span> <span>in the</span> <span>more intense </span><span>TCs. It is unknown to what cause this inverse variation with number and intensity should be generally linked to similar large-scale environmental conditions. To examine the WNP TC genesis and intensity with environmental variables, we show that most of the current trend of decreasing genesis of TCs can be attributed to weakened dynamic environments and the current trend of increasing intensity of TCs might be linked to increased thermodynamic environments. Thus, the future climate warms under RCP 8.5 will likely lead to strong reductions in TC genesis frequency over the WNP, with project decreases of 36-63% by the end of the twenty-first century, but lead to greater TC intensities with rapid development of thermodynamic environments.</span></p>

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