scholarly journals Spatiotemporal Variation of Cold Eddies in the Upwelling Zone off Northeastern Taiwan Revealed by the Geostationary Satellite Imagery of Ocean Color and Sea Surface Temperature

2019 ◽  
Vol 11 (24) ◽  
pp. 6979
Author(s):  
Hsiao-Wei Chung ◽  
Cheng-Chien Liu
Keyword(s):  
Hot Spots ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
Ocean Eddies ◽  
The North ◽  
Mesoscale Ocean Eddies ◽  
Temporal And Spatial ◽  
Major Factors ◽  
The Kuroshio ◽  
The North Pacific

The upwelling zone off northeastern Taiwan (UZONT) is one of the hot spots with mesoscale ocean eddies (MOEs) and eddy-induced transports in the north Pacific Ocean. We start from the temporal and spatial variations in MOEs in the UZONT, based on the Himawari-8 SST product and the GOCI chlorophyll-a product time series, respectively. Their relationship with three major factors, including the Kuroshio, typhoon, and El Niño/La Niña events, are then investigated. The spatiotemporal variations in MOEs serve as ideal indicators by which to understand the influences on the UZONT due to interannual environmental factors and climate change.

scholarly journals Neural Network Approach to Retrieving Ocean Subsurface Temperatures from Surface Parameters Observed by Satellites

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 388
Author(s):  
Hao Cheng ◽  
Liang Sun ◽  
Jiagen Li
Keyword(s):  
Neural Network ◽  
Pacific Ocean ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
Satellite Measurements ◽  
Surface Parameters ◽  
The North ◽  
The North Pacific ◽  
Bpnn Model

The extraction of physical information about the subsurface ocean from surface information obtained from satellite measurements is both important and challenging. We introduce a back-propagation neural network (BPNN) method to determine the subsurface temperature of the North Pacific Ocean by selecting the optimum input combination of sea surface parameters obtained from satellite measurements. In addition to sea surface height (SSH), sea surface temperature (SST), sea surface salinity (SSS) and sea surface wind (SSW), we also included the sea surface velocity (SSV) as a new component in our study. This allowed us to partially resolve the non-linear subsurface dynamics associated with advection, which improved the estimated results, especially in regions with strong currents. The accuracy of the estimated results was verified with reprocessed observational datasets. Our results show that the BPNN model can accurately estimate the subsurface (upper 1000 m) temperature of the North Pacific Ocean. The corresponding mean square errors were 0.868 and 0.802 using four (SSH, SST, SSS and SSW) and five (SSH, SST, SSS, SSW and SSV) input parameters and the average coefficients of determination were 0.952 and 0.967, respectively. The input of the SSV in addition to the SSH, SST, SSS and SSW therefore has a positive impact on the BPNN model and helps to improve the accuracy of the estimation. This study provides important technical support for retrieving thermal information about the ocean interior from surface satellite remote sensing observations, which will help to expand the scope of satellite measurements of the ocean.

Recent intensified influence of the winter North Pacific sea surface temperature on the withdrawal date of Meiyu

2021 ◽  
pp. 1-53
Author(s):  
Hua Li ◽  
Shengping He ◽  
Ke Fan ◽  
Yong Liu ◽  
Xing Yuan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Interannual Variability ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
The North ◽  
Time Period ◽  
The North Pacific ◽  
Sst Anomalies

AbstractThe Meiyu withdrawal date (MWD) is a crucial indicator of flood/drought conditions over East Asia. It is characterized by a strong interannual variability, but its underlying mechanism remains unknown. We investigated the possible effects of the winter sea surface temperature (SST) in the North Pacific Ocean on the MWD on interannual to interdecadal timescales. Both our observations and model results suggest that the winter SST anomalies associated with the MWD are mainly contributed by a combination of the first two leading modes of the winter SST in the North Pacific, which have a horseshoe shape (the NPSST). The statistical results indicate that the intimate linkage between the NPSST and the MWD has intensified since the early 1990s. During the time period 1990–2016, the NPSST-related SST anomalies persisted from winter to the following seasons and affected the SST over the tropical Pacific in July. Subsequently, the SST anomalies throughout the North Pacific strengthened the southward migration of the East Asian jet stream (EAJS) and the southward and westward replacement of the western North Pacific subtropical high (WPSH), leading to an increase in Meiyu rainfall from July 1 to 20. More convincingly, the anomalous EAJS and WPSH induced by the SST anomalies can be reproduced well by numerical simulations. By contrast, the influence of the NPSST on the EASJ and WPSH were not clear between 1961 and 1985. This study further illustrates that the enhanced interannual variability of the NPSST may be attributed to the more persistent SST anomalies during the time period 1990–2016.

scholarly journals Investigating the Role of Ocean–Atmosphere Coupling in the North Pacific Ocean

2014 ◽  
Vol 27 (2) ◽  
pp. 592-606 ◽  
Author(s):  
Dimitry Smirnov ◽  
Matthew Newman ◽  
Michael A. Alexander
Keyword(s):  
North Pacific ◽  
Climate Model ◽  
North Pacific Ocean ◽  
Global Climate Model ◽  
The North ◽  
Sst Variability ◽  
Oceanic Forcing ◽  
Noise Forcing ◽  
The Kuroshio ◽  
The North Pacific

Abstract Air–sea interaction over the North Pacific is diagnosed using a simple, local coupled autoregressive model constructed from observed 7-day running-mean sea surface temperature (SST) and 2-m air temperature TA anomalies during the extended winter from the 1° × 1° objectively analyzed air–sea fluxes (OAFlux) dataset. Though the model is constructed from 1-week lag statistics, it successfully reproduces the observed anomaly evolution through lead times of 90 days, allowing an estimation of the relative roles of coupling and internal atmospheric and oceanic forcing upon North Pacific SSTs. It is found that east of the date line, SST variability is maintained by, but has little effect on, TA variability. However, in the Kuroshio–Oyashio confluence and extension region, about half of the SST variability is independent of TA, driven instead by SST noise forcing internal to the ocean. Including surface zonal winds in the analysis does not alter this conclusion, suggesting TA adequately represents the atmosphere. Repeating the analysis with the output of two control simulations from a fully coupled global climate model (GCM) differing only in their ocean resolution yields qualitatively similar results. However, for the simulation employing the coarse-resolution (1°) ocean model, all SST variability depends upon TA, apparently caused by a near absence of ocean-induced noise forcing. Collectively, these results imply that a strong contribution from internal oceanic forcing drives SST variability in the Kuroshio–Oyashio region, which may be used as a justification for atmospheric GCM experiments forced with SST anomalies in that region alone. This conclusion is unaffected by increasing the dimensionality of the model to allow for intrabasin interaction.

Why Does Global Warming Weaken the Gulf Stream but Intensify the Kuroshio?

2019 ◽  
Vol 32 (21) ◽  
pp. 7437-7451 ◽  
Author(s):  
Changlin Chen ◽  
Guihua Wang ◽  
Shang-Ping Xie ◽  
Wei Liu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
North Atlantic ◽  
North Pacific ◽  
Gulf Stream ◽  
Sea Surface ◽  
Surface Warming ◽  
The North ◽  
The Kuroshio ◽  
The North Pacific

ABSTRACT The Kuroshio and Gulf Stream, the subtropical western boundary currents of the North Pacific and North Atlantic, play important roles in meridional heat transport and ocean–atmosphere interaction processes. Using a multimodel ensemble of future projections, we show that a warmer climate intensifies the upper-layer Kuroshio, in contrast to the previously documented slowdown of the Gulf Stream. Our ocean general circulation model experiments show that the sea surface warming, not the wind change, is the dominant forcing that causes the upper-layer Kuroshio to intensify in a warming climate. Forced by the sea surface warming, ocean subduction and advection processes result in a stronger warming to the east of the Kuroshio than to the west, which increases the isopycnal slope across the Kuroshio, and hence intensifies the Kuroshio. In the North Atlantic, the Gulf Stream slows down as part of the Atlantic meridional overturning circulation (AMOC) response to surface salinity decrease in the high latitudes under global warming. The distinct responses of the Gulf Stream and Kuroshio to climate warming are accompanied by different regional patterns of sea level rise. While the sea level rise accelerates along the northeastern U.S. coast as the AMOC weakens, it remains close to the global mean rate along the East Asian coast as the intensifying Kuroshio is associated with the enhanced sea level rise offshore in the North Pacific subtropical gyre.

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