Tseng Yu-Heng

No Thumbnail Available
Last Name
Tseng
First Name
Yu-Heng
ORCID
0000-0002-4816-4974

Filters

2015 - 2019 2 2020 - 2021 2
4
4
Reset filters

Settings

Search Results

Now showing 1 - 4 of 4
  • Article
    Coupled ocean–atmosphere modeling and predictions
    (Sears Foundation for Marine Research, 2017-05-01) Miller, Arthur J. ; Collins, Matthew ; Gualdi, Silvio ; Jensen, Tommy G. ; Misra, Vasu ; Pezzi, Luciano Ponzi ; Pierce, David W. ; Putrasahan, Dian ; Seo, Hyodae ; Tseng, Yu-Heng
    Key aspects of the current state of the ability of global and regional climate models to represent dynamical processes and precipitation variations are summarized. Interannual, decadal, and global-warming timescales, wherein the influence of the oceans is relevant and the potential for predictability is highest, are emphasized. Oceanic influences on climate occur throughout the ocean and extend over land to affect many types of climate variations, including monsoons, the El Niño Southern Oscillation, decadal oscillations, and the response to greenhouse gas emissions. The fundamental ideas of coupling between the ocean-atmosphere-land system are explained for these modes in both global and regional contexts. Global coupled climate models are needed to represent and understand the complicated processes involved and allow us to make predictions over land and sea. Regional coupled climate models are needed to enhance our interpretation of the fine-scale response. The mechanisms by which large-scale, low-frequency variations can influence shorter timescale variations and drive regionalscale effects are also discussed. In this light of these processes, the prospects for practical climate predictability are also presented.
  • Article
    Could the North Pacific Oscillation be modified by the initiation of the East Asian winter monsoon?
    (American Meteorological Society, 2020-02-21) Tseng, Yu-Heng ; Ding, Ruiqiang ; Zhao, Sen ; Kuo, Yi-chun ; Liang, Yu-Chiao
    This study investigates the modulation of North Pacific Oscillation (NPO) variability upon initiation of the East Asian winter monsoon (EAWM). The data show that the initiation of EAWM in the Philippine Sea strongly connects to the southern lobe variability of the NPO in January followed by a basin-scale oceanic Victoria mode pattern. No apparent connection was found for the northern lobe of the NPO when the ENSO signals are removed. The strengthening of the EAWM in November interacts with the Kuroshio front and generates a low-level heating source in the Philippine Sea. Significant Rossby wave sources are then formed in the lower to midtroposphere. Wave ray tracing analyses confirm the atmospheric teleconnection established by the Rossby wave propagation in the mid- to upper troposphere. Analyses of the origin of wave trajectories from the Philippine Sea show a clear eastward propagating pathway that affects the southern lobe of the NPO from the southern lobe of the western Pacific pattern at 500 hPa and above on the time scale of 20 days. No ray trajectories from the lower troposphere can propagate eastward to influence the central-eastern subtropical Pacific. The wave propagation process is further supported by the coupled model experiments.
  • Article
    Mean structure and fluctuations of the Kuroshio east of Taiwan from in situ and remote observations
    (The Oceanography Society, 2015-12) Yang, Yiing-Jang ; Jan, Sen ; Chang, Ming-Huei ; Wang, Joe ; Mensah, Vigan ; Kuo, Tien-Hsia ; Tsai, Cheng-Ju ; Lee, Chung-Yaung ; Andres, Magdalena ; Centurioni, Luca R. ; Tseng, Yu-Heng ; Liang, Wen-Der ; Lai, Jian-Wu
    The Kuroshio is important to climate, weather prediction, and fishery management along the northeast coast of Asia because it transports tremendous heat, salt, and energy from east of the Philippines to waters southeast of Japan. In the middle of its journey northward, the Kuroshio’s velocity mean and its variability east of Taiwan crucially affect its downstream variability. To improve understanding of the Kuroshio there, multiple platforms were used to collect intensive observations off Taiwan during the three-year Observations of the Kuroshio Transports and their Variability (OKTV) program (2012–2015). Mean Kuroshio velocity transects show two velocity maxima southeast of Taiwan, with the primary velocity core on the onshore side of the Kuroshio exhibiting a mean maximum velocity of ~1.2 m s–1. The two cores then merge and move at a single velocity maximum of ~1 m s–1 east of Taiwan. Standard deviations of both the directly measured poleward (v) and zonal (u) velocities are ~0.4 m s–1 in the Kuroshio main stream. Water mass exchange in the Kuroshio east of Taiwan was found to be complicated, as it includes water of Kuroshio origin, South China Sea Water, and West Philippine Sea Water, and it vitally affects heat, salt, and nutrient inputs to the East China Sea. Impinging eddies and typhoons are two of the principal causes of variability in the Kuroshio. This study’s models are more consistent with the observed Kuroshio than with high-frequency radar measurements.
  • Article
    Terrestrial water storage anomalies emphasize interannual variations in global mean sea level during 1997-1998 and 2015-2016 El Nino Events
    (American Geophysical Union, 2021-09-07) Kuo, Yan-Ning ; Lo, Min-Hui ; Liang, Yu-Chiao ; Tseng, Yu-Heng ; Hsu, Chia-Wei
    Interannual variations in global mean sea level (GMSL) closely correlate with the evolution of El Niño-Southern Oscillation. However, GMSL differences occur in extreme El Niños; for example, in the 2015–2016 and 1997–1998 El Niños, the peak GMSL during the mature stage of the former (9.00 mm) is almost 2.5 times higher than the latter (3.72 mm). Analyses from satellite and reanalysis data sets show that the disparity in GMSL is primarily due to barystatic (ocean mass) changes. We find that the 2015–2016 event developed not purely as an Eastern Pacific El Niño event but with Central Pacific (CP) El Niño forcing. CP El Niños contribute to a stronger negative anomaly of global terrestrial water storage and subsequent higher barystatic heights. Our results suggest that the mechanism of hydrology-related interannual variations of GMSL should be further emphasized, as more CP El Niño events are projected to occur.