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Professor/Dr. Chung-Ru Ho received his Ph.D. in Applied Ocean Science from the University of Delaware, USA in 1994. He is now a professor in the Department of Marine Environmental Informatics, National Taiwan Ocean University, Taiwan. He was a Deputy Director General of National Museum of Marine Science and Technology, Taiwan. He is currently serving as a Committee Member of the Committee on Space Research (COSPAR) and International Union of Geodesy and Geophysics (IUGG). His research interests include eddy-current interaction, typhoon-ocean interaction, global change and climate variability, and ocean dynamics.
Sea surface currents observed by high-frequency (HF) radars have been widely used in ocean circulation research. In this study, hourly sea surface currents observed by the Taiwan Coastal Ocean Dynamics Applications Radar (CODAR) system from 2015 to 2019 were analyzed by the empirical orthogonal function (EOF) analysis to reveal the characteristics of the sea surface currents around Taiwan Island. The study area is divided into two regions, the Kuroshio region east of Taiwan Island and the Taiwan Strait west of Taiwan Island. In the Kuroshio region, the first EOF mode shows that the Kuroshio is characterized by higher current speeds with greater variability in summer. The second and third EOF modes present a dipole eddy pair and single eddy impingement on the Kuroshio during different periods. The seasonal variation of the dipole eddy pair indicates that the cyclonic/anticyclonic eddy on the north/south side appears more frequently in summer. Single eddy impingement occurs at multiple periods, including daily, intraseasonal, interseasonal, and annual periods. For the Taiwan Strait, the first EOF mode displays the tide signals. The tides enter the Taiwan Strait from the north and south, forming strong sea surface currents around the northern tip of Taiwan Island and the Penghu Archipelago. The second EOF mode exhibits the seasonal changes of the sea surface currents driven by the monsoon winds. The sea surface currents in the northern Taiwan Strait are relatively strong, possibly due to the narrow and shallow terrain there. The high spatiotemporal resolution of sea surface currents derived from CODAR observations provide more detailed characteristics of sea surface circulation around Taiwan Island.
Yu-Hao Tseng; Ching-Yuan Lu; Quanan Zheng; Chung-Ru Ho. Characteristic Analysis of Sea Surface Currents around Taiwan Island from CODAR Observations. Remote Sensing 2021, 13, 3025 .
AMA StyleYu-Hao Tseng, Ching-Yuan Lu, Quanan Zheng, Chung-Ru Ho. Characteristic Analysis of Sea Surface Currents around Taiwan Island from CODAR Observations. Remote Sensing. 2021; 13 (15):3025.
Chicago/Turabian StyleYu-Hao Tseng; Ching-Yuan Lu; Quanan Zheng; Chung-Ru Ho. 2021. "Characteristic Analysis of Sea Surface Currents around Taiwan Island from CODAR Observations." Remote Sensing 13, no. 15: 3025.
Evidence of the rapid degradation of the Earth’s natural environment has grown in recent years
Yuei-An Liou; Yuriy Kuleshov; Chung-Ru Ho; Kim-Anh Nguyen; Steven Reising. Preface: Earth Observations for Environmental Sustainability for the Next Decade. Remote Sensing 2021, 13, 2871 .
AMA StyleYuei-An Liou, Yuriy Kuleshov, Chung-Ru Ho, Kim-Anh Nguyen, Steven Reising. Preface: Earth Observations for Environmental Sustainability for the Next Decade. Remote Sensing. 2021; 13 (15):2871.
Chicago/Turabian StyleYuei-An Liou; Yuriy Kuleshov; Chung-Ru Ho; Kim-Anh Nguyen; Steven Reising. 2021. "Preface: Earth Observations for Environmental Sustainability for the Next Decade." Remote Sensing 13, no. 15: 2871.
The barrier layer (BL) is a layer of water separating the thermocline from the density mixed layer in the upper ocean, which has the capability of reducing the negative feedback effect caused by tropical cyclone (TC) acting on the upper ocean and back on the TC itself. This study analyzed in-situ Argo floats measurements, data-assimilated HYCOM/NCODA reanalysis, and the longer-term (1961–2010) variations of Ocean Reanalysis System 4 (ORAS4) based BL in the TC main development region (MDR) to characterize the BL in the western North Pacific (WNP) for different temporal scales and to understand its role in resisting TC induced sea surface cooling. First, the result indicates that the effect of BL on TC enhancement in the MDR of WNP might be overestimated. Further analysis based on partial correlation shows that the BL plays a key role in resisting the cooling response only while BL is strong (BL thickness ≥ 5 m) and TC wind forcing is weak. Meanwhile, the distribution of BL demonstrates markedly the mesoscale characteristic. BL with thickness 0–5 m occupies the highest proportion (~67.55%), while thicker BL (BL thickness (BLT) larger than 5 m) takes up about 25–30%. Besides, there are ~3% with BL thicker than 30 m. For life length, BLT with 0–5 m is limited to 5 days, while BL with thickness more than 30 m can persist for more than 30 days. The scenario is attributed to diverse processes that result in different characteristic temporal scales of BL. Additionally, the analysis of coverage region and average BLT in the recent decade shows a serious situation: both the spatial coverage and BLT increase sharply from 2001 to 2010, which implies that TC–BL interactions might occur more frequently and more vigorously in future if the changing trend of BL remains unchanged.
Ding-Rong Wu; Zhe-Wen Zheng; Ganesh Gopalakrishnan; Chung-Ru Ho; Quanan Zheng. Barrier Layer Characteristics for Different Temporal Scales and Its Implication to Tropical Cyclone Enhancement in the Western North Pacific. Sustainability 2021, 13, 3375 .
AMA StyleDing-Rong Wu, Zhe-Wen Zheng, Ganesh Gopalakrishnan, Chung-Ru Ho, Quanan Zheng. Barrier Layer Characteristics for Different Temporal Scales and Its Implication to Tropical Cyclone Enhancement in the Western North Pacific. Sustainability. 2021; 13 (6):3375.
Chicago/Turabian StyleDing-Rong Wu; Zhe-Wen Zheng; Ganesh Gopalakrishnan; Chung-Ru Ho; Quanan Zheng. 2021. "Barrier Layer Characteristics for Different Temporal Scales and Its Implication to Tropical Cyclone Enhancement in the Western North Pacific." Sustainability 13, no. 6: 3375.
The Kuroshio Current has its origin in the northwestern Pacific, flowing northward to the east of Taiwan and the northern part of Luzon Island. As the Kuroshio Current flows northward, it quasi-periodically intrudes (hereafter referred to as Kuroshio intrusion (KI)) into the northern South China Sea (SCS) basin through the Luzon Strait. Despite the complex generation mechanisms of KI, the purpose of this study is to improve our understanding of the effects of KI through the Luzon Strait on the regional atmospheric and weather variations. Long-term multiple satellite observations, including absolute dynamic topography, absolute geostrophic currents, sea surface winds by ASCAT, multi-scale ultra-high resolution sea surface temperature (MURSST) level-four analysis, and research-quality three-hourly TRMM multi-satellite precipitation analysis (TMPA), was used to systematically examine the aforementioned scientific problem. Analysis indicates that the KI is interlinked with the consequential anomalous precipitation off southwestern Taiwan. This anomalous precipitation would lead to ~560 million tons of freshwater influx during each KI event. Subsequently, independent moisture budget analysis suggests that moisture, mainly from vertical advection, is the possible source of the precipitation anomaly. Additionally, a bulk formula analysis was applied to understand how KI can trigger the precipitation anomaly through vertical advection of moisture without causing an evident change in the low-level flows. These new research findings might reconcile the divisiveness on why winds are not showing a synchronous response during the KI and consequential anomalous precipitation events.
Wen-Pin Fang; Ding-Rong Wu; Zhe-Wen Zheng; Ganesh Gopalakrishnan; Chung-Ru Ho; Quanan Zheng; Chen-Fen Huang; Hua Ho; Min-Chuan Weng. Impacts of the Kuroshio Intrusion through the Luzon Strait on the Local Precipitation Anomaly. Remote Sensing 2021, 13, 1113 .
AMA StyleWen-Pin Fang, Ding-Rong Wu, Zhe-Wen Zheng, Ganesh Gopalakrishnan, Chung-Ru Ho, Quanan Zheng, Chen-Fen Huang, Hua Ho, Min-Chuan Weng. Impacts of the Kuroshio Intrusion through the Luzon Strait on the Local Precipitation Anomaly. Remote Sensing. 2021; 13 (6):1113.
Chicago/Turabian StyleWen-Pin Fang; Ding-Rong Wu; Zhe-Wen Zheng; Ganesh Gopalakrishnan; Chung-Ru Ho; Quanan Zheng; Chen-Fen Huang; Hua Ho; Min-Chuan Weng. 2021. "Impacts of the Kuroshio Intrusion through the Luzon Strait on the Local Precipitation Anomaly." Remote Sensing 13, no. 6: 1113.
The waters in the north of Taiwan are located at the southern end of the East China Sea (ECS), adjacent to the Taiwan Strait (TS), and the Kuroshio region. To understand the physical dynamic process of ocean currents and the temporal and spatial distribution of the ocean chlorophyll concentration in the north of Taiwan, hourly coastal ocean dynamics applications radar (CODAR) flow field data and geostationary ocean color imager (GOCI) data are analyzed here. According to data from December 2014 to May 2020, the water in the TS flows along the northern coast of Taiwan into the Kuroshio region with a velocity of 0.13 m/s in spring and summer through the ECS. In winter, the Kuroshio invades the ECS shelf, where the water flows into the TS through the ECS with a velocity of 0.08 m/s. The seasonal variation of ocean chlorophyll concentration along the northwestern coast of Taiwan is obvious, where the average chlorophyll concentration from November to January exceeds 2.0 mg/m3, and the lowest concentration in spring is 1.4 mg/m3. It is apparent that the tidal currents in the north of Taiwan flow eastward and westward during ebb and flood periods, respectively. Affected by the background currents, the flow velocity exhibits significant seasonal changes, namely, 0.43 m/s in summer and 0.27 m/s in winter during the ebb period and is 0.26 m/s in summer and 0.45 m/s in winter during the flood period. The chlorophyll concentration near the shore is also significantly affected by the tidal currents. Based on CODAR data, virtual drifter experiments, and GOCI data, this research provides novel and important knowledge of ocean current movement process in the north of Taiwan and indicates diurnal to seasonal variations in the ocean chlorophyll concentration, facilitating future research on the interaction between the TS, ECS, and Kuroshio.
Po-Chun Hsu; Ching-Yuan Lu; Tai-Wen Hsu; Chung-Ru Ho. Diurnal to Seasonal Variations in Ocean Chlorophyll and Ocean Currents in the North of Taiwan Observed by Geostationary Ocean Color Imager and Coastal Radar. Remote Sensing 2020, 12, 2853 .
AMA StylePo-Chun Hsu, Ching-Yuan Lu, Tai-Wen Hsu, Chung-Ru Ho. Diurnal to Seasonal Variations in Ocean Chlorophyll and Ocean Currents in the North of Taiwan Observed by Geostationary Ocean Color Imager and Coastal Radar. Remote Sensing. 2020; 12 (17):2853.
Chicago/Turabian StylePo-Chun Hsu; Ching-Yuan Lu; Tai-Wen Hsu; Chung-Ru Ho. 2020. "Diurnal to Seasonal Variations in Ocean Chlorophyll and Ocean Currents in the North of Taiwan Observed by Geostationary Ocean Color Imager and Coastal Radar." Remote Sensing 12, no. 17: 2853.
Tidal current‐induced cyclonic eddies cause cold‐water upwelling and periodic sea surface temperature (SST) drops around the coral reef area in Nanwan Bay, which is located at the southern tip of Taiwan. This study used Himawari‐8 satellite data and tide gauge and coastal ocean dynamics application radar (CODAR) data to analyze the characteristics of the SST drops and cyclonic eddy propagation and used an oceanic general circulation model (OGCM) to simulate the tidal current flowing process. According to the CODAR data analysis, the mixed primary semidiurnal tide had an average current velocity of 0.3–0.4 m s‐1 throughout the bay, and the average life cycle of a cyclonic eddy is 6.6 hr, with a propagation speed of 0.35 m s‐1. The SST drop during the spring tide period was greater than that during the neap tide period, and the SST dropped in both summer and winter. The average daily SST drop in the summer reached 2 °C with a maximum observed value of 4.7 °C, and the SST drop rate was 0.3–0.5 °C hr‐1. The annual mean chlorophyll‐a concentration was 0.25 mg m‐3. This study explored the special properties of the Nanwan Bay coral reef area from the perspective of ocean physics to allow ecologists to facilitate the implementation of long‐term conservation and monitoring programs.
Po‐Chun Hsu; Hung‐Jen Lee; Quanan Zheng; Jian‐Wu Lai; Feng‐Chun Su; Chung‐Ru Ho. Tide‐Induced Periodic Sea Surface Temperature Drops in the Coral Reef Area of Nanwan Bay, Southern Taiwan. Journal of Geophysical Research: Oceans 2020, 125, 1 .
AMA StylePo‐Chun Hsu, Hung‐Jen Lee, Quanan Zheng, Jian‐Wu Lai, Feng‐Chun Su, Chung‐Ru Ho. Tide‐Induced Periodic Sea Surface Temperature Drops in the Coral Reef Area of Nanwan Bay, Southern Taiwan. Journal of Geophysical Research: Oceans. 2020; 125 (4):1.
Chicago/Turabian StylePo‐Chun Hsu; Hung‐Jen Lee; Quanan Zheng; Jian‐Wu Lai; Feng‐Chun Su; Chung‐Ru Ho. 2020. "Tide‐Induced Periodic Sea Surface Temperature Drops in the Coral Reef Area of Nanwan Bay, Southern Taiwan." Journal of Geophysical Research: Oceans 125, no. 4: 1.
Dynamics of ocean current-induced island wake has been an important issue in global oceanography. Green Island, a small island located off southeast of Taiwan on the Kuroshio path was selected as the study area to more understand the spatial structure and temporal variation of well-organized vortices formed by the interaction between the Kuroshio and the island. Sea surface temperature (SST) and chlorophyll-a (Chl-a) concentration data derived from the Himawari-8 satellite and the second generation global imager (SGLI) of global change observation mission (GCOM-C) were used in this study. The spatial SST and Chl-a variations in designed observation lines and the cooling zone transitions on the left and right sides of the vortices were investigated using 250 m spatial resolution GCOM-C data. The Massachusetts Institute of Technology general circulation model (MITgcm) simulation confirmed that the positive and negative vortices were sequentially detached from each other in a few hours. In addition, totals of 101 vortexes from July 2015 to December 2019 were calculated from the 1-h temporal resolution Himawari-8 imagery. The average vortex propagation speed was 0.95 m/s. Totals of 38 cases of two continuous vortices suggested that the average vortex shedding period is 14.8 h with 1.15 m/s of the average incoming surface current speed of Green Island, and the results agreed to the ideal Strouhal-Reynolds number fitting curve relation. Combined with the satellite observation and numerical model simulation, this study demonstrates the structure of the wake area could change quickly, and the water may mix in different vorticity states for each observation station.
Po-Chun Hsu; Chia-Ying Ho; Hung-Jen Lee; Ching-Yuan Lu; Chung-Ru Ho. Temporal Variation and Spatial Structure of the Kuroshio-Induced Submesoscale Island Vortices Observed from GCOM-C and Himawari-8 Data. Remote Sensing 2020, 12, 883 .
AMA StylePo-Chun Hsu, Chia-Ying Ho, Hung-Jen Lee, Ching-Yuan Lu, Chung-Ru Ho. Temporal Variation and Spatial Structure of the Kuroshio-Induced Submesoscale Island Vortices Observed from GCOM-C and Himawari-8 Data. Remote Sensing. 2020; 12 (5):883.
Chicago/Turabian StylePo-Chun Hsu; Chia-Ying Ho; Hung-Jen Lee; Ching-Yuan Lu; Chung-Ru Ho. 2020. "Temporal Variation and Spatial Structure of the Kuroshio-Induced Submesoscale Island Vortices Observed from GCOM-C and Himawari-8 Data." Remote Sensing 12, no. 5: 883.
As climate change has been of great concern worldwide for many years, addressing global climate challenges is the most significant task for humanity
Yuei-An Liou; Yuriy Kuleshov; Chung-Ru Ho; Jean-Pierre Barriot; Chyi-Tyi Lee. Preface: Earth Observations for Addressing Global Challenges. Remote Sensing 2020, 12, 841 .
AMA StyleYuei-An Liou, Yuriy Kuleshov, Chung-Ru Ho, Jean-Pierre Barriot, Chyi-Tyi Lee. Preface: Earth Observations for Addressing Global Challenges. Remote Sensing. 2020; 12 (5):841.
Chicago/Turabian StyleYuei-An Liou; Yuriy Kuleshov; Chung-Ru Ho; Jean-Pierre Barriot; Chyi-Tyi Lee. 2020. "Preface: Earth Observations for Addressing Global Challenges." Remote Sensing 12, no. 5: 841.
Katabatic winds generally flow from mountains or hills down to their lee side in the paths of depression. If the mountain or hill is near a coast, the katabatic winds may cause imprints on the sea surface. The katabatic wind pattern shown on a synthetic aperture radar (SAR) image is a bright-dark region that mirrors the coastal mountain topography. In this study, bright regions on SAR images caused by katabatic winds are found in the west of Hengchun Peninsula where is located in the southern Taiwan. The katabatic winds cause the sea state variations and then the sea surface temperature changes. Relationships between normalized radar cross section (NRCS) and sea surface temperature (SST) as well as the temperature difference between air and sea in the west of Hengchun Peninsula are investigated to find out the air-sea heat transfer. The results show that 1) the SST decreases when the NRCS increases, that is, the higher wind speed would cause the SST lower; and 2) the gradient of linear relationship between NRCS and SST is related to the temperature difference between air and sea, that is, the higher temperature difference could increase the release of heat from the ocean to the atmosphere.
Chung-Ru Ho; Fei Lai. Sea surface temperature changes with katabatic winds observed from IR and SAR images. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019 2019, 11150, 1115014 .
AMA StyleChung-Ru Ho, Fei Lai. Sea surface temperature changes with katabatic winds observed from IR and SAR images. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019. 2019; 11150 ():1115014.
Chicago/Turabian StyleChung-Ru Ho; Fei Lai. 2019. "Sea surface temperature changes with katabatic winds observed from IR and SAR images." Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019 11150, no. : 1115014.
This study uses the MODIS-Aqua satellite data provided by the National Aeronautics and Space Administration (NASA) and matches with the time and location of the chlorophyll-a concentration data measured by SeaBASS to select the satellite data time and observation area. The number of matched data is 924. Firstly, remote sensing reflectance (Rrs) is used to classify satellite remote sensing data into different water bodies, and then the best chlorophyll-a concentration algorithm is established. The results show that the mean percentage difference (MPD) in Case 2 water is 131.2% through comparing the percentage of chlorophyll-a provided by MODIS with the in-situ observations. In addition, the chlorophyll-a concentration of the new algorithm compared with the in-situ chlorophyll-a concentration are also calculated. The mean percentage difference in Case 2 water is 26.6%, and the average chlorophyll-a is 6.16 mg/m3 , which is much closer to the in-situ value,7.22 mg/m3 than the average chlorophyll-a of MODIS, 13.7 mg/m3. The chlorophyll-a concentration deduced by the new algorithm of this study is consistent with the in-situ values in Case 2 water, and it is much more convergent than the data of MODIS. Obviously, the new algorithm established in this study can be used to improve the chlorophyll-a concentration estimation results in Case 2 water. When the new algorithm is applied to calculate the chlorophyll-a concentration of the marginal Northwestern Pacific, the value is still higher than the offshore waters. Additionally, the chlorophyll-a concentration calculated by this new algorithm is lower than the value provided by MODIS, but the difference between them in the offshore waters is small. However, the algorithm of this study can improve the overestimation of the original MODIS value.
Shih-Jen Huang; Chung-Ru Ho; Yao-Tsai Lo. Satellite-based estimating chlorophyll-a concentration in the marginal Northwest Pacific. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019 2019, 11150, 111501B .
AMA StyleShih-Jen Huang, Chung-Ru Ho, Yao-Tsai Lo. Satellite-based estimating chlorophyll-a concentration in the marginal Northwest Pacific. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019. 2019; 11150 ():111501B.
Chicago/Turabian StyleShih-Jen Huang; Chung-Ru Ho; Yao-Tsai Lo. 2019. "Satellite-based estimating chlorophyll-a concentration in the marginal Northwest Pacific." Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2019 11150, no. : 111501B.
This study examines a Kuroshio main path (KMP) cut-off event east of Taiwan Island occurred in fall-winter 2013–2014 and its impacts on the South China Sea (SCS) by analyzing satellite altimetry and mooring observations. Satellite altimeter sea level anomaly (SLA) images reveal a complete process that a huge cyclonic eddy (CE) from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014. Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82% from 17×106 m3/s in September to 3×106 m3/s in November 2013. The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait. Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event.
Quanan Zheng; Chung-Ru Ho; Lingling Xie; Mingming Li. A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014. Acta Oceanologica Sinica 2019, 38, 12 -19.
AMA StyleQuanan Zheng, Chung-Ru Ho, Lingling Xie, Mingming Li. A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014. Acta Oceanologica Sinica. 2019; 38 (4):12-19.
Chicago/Turabian StyleQuanan Zheng; Chung-Ru Ho; Lingling Xie; Mingming Li. 2019. "A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014." Acta Oceanologica Sinica 38, no. 4: 12-19.
When the Kuroshio passes Green Island off Taiwan, well-organized wakes are formed by the interaction between the Kuroshio and the island. The vertical mixing in the wake produces cold water, which entrains from the mixed layer below the surface and results in relatively colder and saltier waters with a higher chlorophyll-a concentration on the sea surface to the lee of the island. The meander of the Kuroshio maximum velocity axis has a major influence on the island wake. The shift of the Kuroshio in front of Green Island not only weakens the flow velocity but also affects the development of the wake. In the Green Island wake, the density overturns with a Thorpe scale between 2.9 m and 20.5 m and the turbulent kinetic energy dissipation rate is 0.2×10−6–8.5×10−5 Wkg−1, which corresponds to an eddy diffusivity in the range of 0.01–0.23 m2s−1. The spatial distribution patterns of the sea surface temperature (SST) in the island wake are classified into four distinct types, as obtained from moderate-resolution imaging spectroradiometer (MODIS) SST images. The most frequently occurring type is of the wake alone, which accounts for 86.7% of the island wake patterns. The other three types are a wake with a tail stretching downstream (4.0%), a wake with a small cyclonic cold core but no tail stretching downstream (6.8%) and an S-shaped meandering wake (2.5%).
Po-Chun Hsu; Kai-Ho Cheng; Sen Jan; Hung-Jen Lee; Chung-Ru Ho. Vertical structure and surface patterns of Green Island wakes induced by the Kuroshio. Deep Sea Research Part I: Oceanographic Research Papers 2018, 143, 1 -16.
AMA StylePo-Chun Hsu, Kai-Ho Cheng, Sen Jan, Hung-Jen Lee, Chung-Ru Ho. Vertical structure and surface patterns of Green Island wakes induced by the Kuroshio. Deep Sea Research Part I: Oceanographic Research Papers. 2018; 143 ():1-16.
Chicago/Turabian StylePo-Chun Hsu; Kai-Ho Cheng; Sen Jan; Hung-Jen Lee; Chung-Ru Ho. 2018. "Vertical structure and surface patterns of Green Island wakes induced by the Kuroshio." Deep Sea Research Part I: Oceanographic Research Papers 143, no. : 1-16.
The interaction of coastal water in I-Lan Bay, a bay near northeast Taiwan, and the Kuroshio Current is studied using the data from hydrologic survey and satellite remote sensing. An index for water mass distinguished is used for clarifying the origin of water mass in I-Lan Bay. The velocity profile from acoustic Doppler current profile data indicates a countercurrent that flows southward along the northeast coast of Taiwan toward I-Lan Bay with a speed around 0.1–0.2 m/s. The index of water mass indicates that the water of I-Lan Bay is mainly affected by the northern shelf waters of Taiwan and mixed with Kuroshio nearshore water, thus forming a clear ocean front between these two areas. The near surface water temperature in the I-Lan Bay is about 2 °C lower than that in the Kuroshio region. The seasonal average near surface salinity of I-Lan Bay can exist 0.4 psu fresher than the Kuroshio area. From the analysis of dynamic process, the coastal countercurrent in I-Lan Bay is primarily affected by 1) the occurrence of cold dome in northeast of Taiwan mainly occurs in summer, and 2) the wind-driven current from the Taiwan Strait along the north coast and the northeast coast of Taiwan caused by the southwesterly monsoon makes the countercurrents strongly in summer. The dynamics of the countercurrent occurrence can be explained by the Ekman transport theory.
Po-Chun Hsu; Quanan Zheng; Ching-Yuan Lu; Kai-Ho Cheng; Hung-Jen Lee; Chung-Ru Ho. Interaction of coastal countercurrent in I-Lan Bay with the Kuroshio northeast of Taiwan. Continental Shelf Research 2018, 171, 30 -41.
AMA StylePo-Chun Hsu, Quanan Zheng, Ching-Yuan Lu, Kai-Ho Cheng, Hung-Jen Lee, Chung-Ru Ho. Interaction of coastal countercurrent in I-Lan Bay with the Kuroshio northeast of Taiwan. Continental Shelf Research. 2018; 171 ():30-41.
Chicago/Turabian StylePo-Chun Hsu; Quanan Zheng; Ching-Yuan Lu; Kai-Ho Cheng; Hung-Jen Lee; Chung-Ru Ho. 2018. "Interaction of coastal countercurrent in I-Lan Bay with the Kuroshio northeast of Taiwan." Continental Shelf Research 171, no. : 30-41.
Underwater gliders are used to investigate the variations on the ocean surface and subsurface during the 14 typhoons that passed over the Kuroshio region near Taiwan in 2010–2013. Typhoon-induced subsurface layer warming, which was formed on the basis of the heat pump effect of the vertical mixing process, is observed in this study. In addition, the gliders observe the variations in salinity during the passage of the typhoons. Typhoons, accompanied by heavy rainfall, introduce a considerable amount of fresh water into the upper ocean, diluting the surface salinity. The diluted salinity accompanied deepening of the mixed layer which moved downward to the subsurface by vertical mixing, supplying fresh water to both the surface and subsurface layers. Additionally, because of vertical mixing, maximum temperature variations occur at the bottom of the mixed layer or at a level deeper than the mixed layer. Changes of the heat content show that a series of vertical mixing events occurs in the upper ocean. Pairs of salinity profiles indicate comprehensive vertical mixing in the upper ocean and yield schematics to compare typhoons with or without heavy rainfall. Higher sustained wind speeds may contribute to a considerable drop in sea surface temperature, but possibly not to the magnitude of the subsurface warming. The upper ocean thermocline gradient before a typhoon is an important factor to determine the magnitude of subsurface warming. This study concludes a glider observational result that typhoons cause subsurface layer warming and freshening in the Kuroshio region near Taiwan.
Po-Chun Hsu; Chung-Ru Ho. Typhoon-induced ocean subsurface variations from glider data in the Kuroshio region adjacent to Taiwan. Journal of Oceanography 2018, 75, 1 -21.
AMA StylePo-Chun Hsu, Chung-Ru Ho. Typhoon-induced ocean subsurface variations from glider data in the Kuroshio region adjacent to Taiwan. Journal of Oceanography. 2018; 75 (1):1-21.
Chicago/Turabian StylePo-Chun Hsu; Chung-Ru Ho. 2018. "Typhoon-induced ocean subsurface variations from glider data in the Kuroshio region adjacent to Taiwan." Journal of Oceanography 75, no. 1: 1-21.
Shih-Jen Huang; Yun-Chan Tsai; Yao-Tsai Lo; Nan-Jung Kuo; Chung-Ru Ho. The influence of tide on sea surface temperature in the marginal sea of northwest Pacific Ocean. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017 2017, 57 .
AMA StyleShih-Jen Huang, Yun-Chan Tsai, Yao-Tsai Lo, Nan-Jung Kuo, Chung-Ru Ho. The influence of tide on sea surface temperature in the marginal sea of northwest Pacific Ocean. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017. 2017; ():57.
Chicago/Turabian StyleShih-Jen Huang; Yun-Chan Tsai; Yao-Tsai Lo; Nan-Jung Kuo; Chung-Ru Ho. 2017. "The influence of tide on sea surface temperature in the marginal sea of northwest Pacific Ocean." Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017 , no. : 57.
Po-Chun Hsu; Chen-Chih Lin; Shih-Jen Huang; Chung-Ru Ho. Satellite observations of rainfall effect on sea surface salinity in the waters adjacent to Taiwan. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017 2017, 39 .
AMA StylePo-Chun Hsu, Chen-Chih Lin, Shih-Jen Huang, Chung-Ru Ho. Satellite observations of rainfall effect on sea surface salinity in the waters adjacent to Taiwan. Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017. 2017; ():39.
Chicago/Turabian StylePo-Chun Hsu; Chen-Chih Lin; Shih-Jen Huang; Chung-Ru Ho. 2017. "Satellite observations of rainfall effect on sea surface salinity in the waters adjacent to Taiwan." Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2017 , no. : 39.
Po-Chun Hsu; Ming-Huei Chang; Chen-Chih Lin; Shih-Jen Huang; Chung-Ru Ho. Investigation of the island-induced ocean vortex train of the Kuroshio Current using satellite imagery. Remote Sensing of Environment 2017, 193, 54 -64.
AMA StylePo-Chun Hsu, Ming-Huei Chang, Chen-Chih Lin, Shih-Jen Huang, Chung-Ru Ho. Investigation of the island-induced ocean vortex train of the Kuroshio Current using satellite imagery. Remote Sensing of Environment. 2017; 193 ():54-64.
Chicago/Turabian StylePo-Chun Hsu; Ming-Huei Chang; Chen-Chih Lin; Shih-Jen Huang; Chung-Ru Ho. 2017. "Investigation of the island-induced ocean vortex train of the Kuroshio Current using satellite imagery." Remote Sensing of Environment 193, no. : 54-64.
In this study, satellite sea surface temperature (SST) dataset is used to study the wakes formed by the Kuroshio flows past Green Island, a small island located off southeast of Taiwan. Satellite thermal Infrared Imagery usually has missing data due to cloud coverage. This situation is difficult for further analyzing. To fill up the missing data and to obtain long-term information, Data Interpolating Empirical Orthogonal Functions is used in the study. These SST images without missing data are then analyzed by the Empirical Orthogonal Function (EOF) method. The first EOF mode explains 99.95% of the total variance and clearly shows a cooling area behind Green Island. Using the gradient EOF method, each mode indicates different wake features, including direction, range, and extended length of the wake. During the data period, the percentage of the wake occurrence was 59%. The average cooling SST was about 0.91±0.15°C. For the extended range of the island wake, there is 63% shorter than 20 km, and only 8% longer than 30 km. In addition, the wake area has 1–3 times higher than surrounding area in chlorophyll-a concentration due to the island mass effect.
Kai-Ho Cheng; Chung-Ru Ho; Po-Chun Hsu. Analyses of Green Island wake caused by Kuroshio from satellite imagery. 2016 Techno-Ocean (Techno-Ocean) 2017, 109 -112.
AMA StyleKai-Ho Cheng, Chung-Ru Ho, Po-Chun Hsu. Analyses of Green Island wake caused by Kuroshio from satellite imagery. 2016 Techno-Ocean (Techno-Ocean). 2017; ():109-112.
Chicago/Turabian StyleKai-Ho Cheng; Chung-Ru Ho; Po-Chun Hsu. 2017. "Analyses of Green Island wake caused by Kuroshio from satellite imagery." 2016 Techno-Ocean (Techno-Ocean) , no. : 109-112.
This study examined the statistical features of eddies approaching the Kuroshio east of Taiwan Island and Luzon Island. In total, 315 eddies (138 anticyclonic and 177 cyclonic eddies) were detected from 19.5 years of satellite altimeter sea-level data, with more than 95% of these eddies being generated in the ocean west of the Mariana Islands. Eddy trajectory statistics indicated that eddies frequently intrude into the Kuroshio regime at two latitude bands, namely 18°N–19°N and 22°N–23°N, with periods of 146 ± 62 and 165 ± 46 days, respectively. The interaction time is longer within the two active bands (33 ± 10 days at 18°N–19°N and 45 ± 17 days at 22°N–23°N) than at other latitudes. These two eddy-intrusion bands are associated with the northern and southern Subtropical Countercurrents (STCCs). These STCCs have a vertically reversed sign of the meridional potential vorticity gradient, thus providing a key energy source for eddy generation. In addition, when westward-propagating eddies approach the Ryukyu Islands, the southwestward recirculation flow east of the island chain as well as topographic effects cause some eddies to head southwestward to the east of Taiwan and intrude into the Kuroshio at 22°N–23°N, rather than to dissipate directly. Therefore, we suggest that the STCCs play a key role in inducing the eddies to frequently intrude into the Kuroshio at 18°N–19°N and 22°N–23°N. In addition, the Ryukyu Islands are responsible for concentrating the eddies within 22°N–23°N.
Yu-Hsin Cheng; Chung-Ru Ho; Quanan Zheng; Bo Qiu; Jianyu Hu; Nan-Jung Kuo. Statistical features of eddies approaching the Kuroshio east of Taiwan Island and Luzon Island. Journal of Oceanography 2017, 73, 427 -438.
AMA StyleYu-Hsin Cheng, Chung-Ru Ho, Quanan Zheng, Bo Qiu, Jianyu Hu, Nan-Jung Kuo. Statistical features of eddies approaching the Kuroshio east of Taiwan Island and Luzon Island. Journal of Oceanography. 2017; 73 (4):427-438.
Chicago/Turabian StyleYu-Hsin Cheng; Chung-Ru Ho; Quanan Zheng; Bo Qiu; Jianyu Hu; Nan-Jung Kuo. 2017. "Statistical features of eddies approaching the Kuroshio east of Taiwan Island and Luzon Island." Journal of Oceanography 73, no. 4: 427-438.
In this study, we analyze the influence of coastal upwelling off southeast Vietnam (CUEV) on local wind field using numerical simulations based on atmospheric model of Weather Research and Forecasting (WRF). Several scenarios are simulated by forcing identical model configurations with different SST fields. Based on simulation results, the relationship between CUEV and reduction of wind forcing is numerically evidenced. With the influence of a typical cold patch with a temperature drop of 3–5 °C, the local wind speeds can drop to less than 70% of original level. We find that the mechanism of response of the wind reduction to CUEV is enhancement of sea-breeze induced wind modulation. Onshore sea-breeze will enhance, while the contrast between land and sea is even more striking due to the contribution of a distinct coastal upwelling. This implies that air-sea-land interaction dominates the process of local wind system modulation in response to transient CUEV. This result sheds a new light on the air-sea interaction process within the SCS basin.
Zhe-Wen Zheng; Quanan Zheng; Yi-Chun Kuo; Ganesh Gopalakrishnan; Chia-Ying Lee; Chung-Ru Ho; Nan-Jung Kuo; Shih-Jen Huang. Impacts of coastal upwelling off east Vietnam on the regional winds system: An air-sea-land interaction. Dynamics of Atmospheres and Oceans 2016, 76, 105 -115.
AMA StyleZhe-Wen Zheng, Quanan Zheng, Yi-Chun Kuo, Ganesh Gopalakrishnan, Chia-Ying Lee, Chung-Ru Ho, Nan-Jung Kuo, Shih-Jen Huang. Impacts of coastal upwelling off east Vietnam on the regional winds system: An air-sea-land interaction. Dynamics of Atmospheres and Oceans. 2016; 76 ():105-115.
Chicago/Turabian StyleZhe-Wen Zheng; Quanan Zheng; Yi-Chun Kuo; Ganesh Gopalakrishnan; Chia-Ying Lee; Chung-Ru Ho; Nan-Jung Kuo; Shih-Jen Huang. 2016. "Impacts of coastal upwelling off east Vietnam on the regional winds system: An air-sea-land interaction." Dynamics of Atmospheres and Oceans 76, no. : 105-115.