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Tropical cyclone (TC) translation speed is an important parameter. In the context of TC–ocean interaction, faster translation speed can contribute to less TC-induced ocean cooling and thus enables more air–sea enthalpy flux supply to favor TC intensification. In 2018, Kossin published an interesting paper in Nature, reporting a global slow-down of TC translation speed since the 1950s. However, upon close inspection, in the last two decades, TC translation speed actually increased over the western North Pacific (WNP) and neighboring seas. Thus, we are interested to see which sub-region in the WNP and neighboring seas had the largest increase during the last two decades, and whether such increases contribute to TC intensification. Our results found statistically significant translation speed increases (~0.8 ms−1 per decade) over the South China Sea. Ruling out other possible factors that may influence TC intensity (i.e., changes in atmospheric vertical wind shear, pre-TC sea surface temperature or subsurface thermal condition), we suggest, in this research, the possible contribution of TC translation speed increases to the observed TC intensity increases over the South China Sea in the last two decades (1998–2017).
Ya-Ting Chang; I-I Lin; Hsiao-Ching Huang; Yi-Chun Liao; Chun-Chi Lien. The Association of Typhoon Intensity Increase with Translation Speed Increase in the South China Sea. Sustainability 2020, 12, 939 .
AMA StyleYa-Ting Chang, I-I Lin, Hsiao-Ching Huang, Yi-Chun Liao, Chun-Chi Lien. The Association of Typhoon Intensity Increase with Translation Speed Increase in the South China Sea. Sustainability. 2020; 12 (3):939.
Chicago/Turabian StyleYa-Ting Chang; I-I Lin; Hsiao-Ching Huang; Yi-Chun Liao; Chun-Chi Lien. 2020. "The Association of Typhoon Intensity Increase with Translation Speed Increase in the South China Sea." Sustainability 12, no. 3: 939.
On 23 August, 2017, Typhoon Hato rapidly intensified by 10 kt within 3 h just prior to landfall in the city of Macau along the South China coast. Hato’s surface winds in excess of 50 m s−1 devastated the city, causing unprecedented damage and social impact. This study reveals that anomalously warm ocean conditions in the nearshore shallow water (depth < 30 m) likely played a key role in Hato’s fast intensification. In particular, cooling of the sea surface temperature (SST) generated by Hato at the critical landfall point was estimated to be only 0.1–0.5 °C. The results from both a simple ocean mixing scheme and full dynamical ocean model indicate that SST cooling was minimized in the shallow coastal waters due to a lack of cool water at depth. Given the nearly invariant SST in the coastal waters, we estimate a large amount of heat flux, i.e., 1.9k W m−2, during the landfall period. Experiments indicate that in the absence of shallow bathymetry, and thus, if nominal cool water had been available for vertical mixing, the SST cooling would have been enhanced from 0.1 °C to 1.4 °C, and sea to air heat flux reduced by about a quarter. Numerical simulations with an atmospheric model suggest that the intensity of Hato was very sensitive to air-sea heat flux in the coastal region, indicating the critical importance of coastal ocean hydrography.
Iam-Fei Pun; Johnny Chan; I.-I. Lin; Kelvin Chan; James Price; Dong Ko; Chun-Chi Lien; Yu-Lun Wu; Hsiao-Ching Huang. Rapid Intensification of Typhoon Hato (2017) over Shallow Water. Sustainability 2019, 11, 3709 .
AMA StyleIam-Fei Pun, Johnny Chan, I.-I. Lin, Kelvin Chan, James Price, Dong Ko, Chun-Chi Lien, Yu-Lun Wu, Hsiao-Ching Huang. Rapid Intensification of Typhoon Hato (2017) over Shallow Water. Sustainability. 2019; 11 (13):3709.
Chicago/Turabian StyleIam-Fei Pun; Johnny Chan; I.-I. Lin; Kelvin Chan; James Price; Dong Ko; Chun-Chi Lien; Yu-Lun Wu; Hsiao-Ching Huang. 2019. "Rapid Intensification of Typhoon Hato (2017) over Shallow Water." Sustainability 11, no. 13: 3709.
Supertyphoon Megi (2010) left behind two very contrasting SST cold-wake cooling patterns between the Philippine Sea (1.5°C) and the South China Sea (7°C). Based on various radii of radial winds, the authors found that the size of Megi doubles over the South China Sea when it curves northward. On average, the radius of maximum wind (RMW) increased from 18.8 km over the Philippine Sea to 43.1 km over the South China Sea; the radius of 64-kt (33 m s−1) typhoon-force wind (R64) increased from 52.6 to 119.7 km; the radius of 50-kt (25.7 m s−1) damaging-force wind (R50) increased from 91.8 to 210 km; and the radius of 34-kt (17.5 m s−1) gale-force wind (R34) increased from 162.3 to 358.5 km. To investigate the typhoon size effect, the authors conduct a series of numerical experiments on Megi-induced SST cooling by keeping other factors unchanged, that is, typhoon translation speed and ocean subsurface thermal structure. The results show that if it were not for Megi’s size increase over the South China Sea, the during-Megi SST cooling magnitude would have been 52% less (reduced from 4° to 1.9°C), the right bias in cooling would have been 60% (or 30 km) less, and the width of the cooling would have been 61% (or 52 km) less, suggesting that typhoon size is as important as other well-known factors on SST cooling. Aside from the size effect, the authors also conduct a straight-track experiment and find that the curvature of Megi contributes up to 30% (or 1.2°C) of cooling over the South China Sea.
Iam-Fei Pun; I.-I. Lin; Chun-Chi Lien; Chun-Chieh Wu. Influence of the Size of Supertyphoon Megi (2010) on SST Cooling. Monthly Weather Review 2018, 146, 661 -677.
AMA StyleIam-Fei Pun, I.-I. Lin, Chun-Chi Lien, Chun-Chieh Wu. Influence of the Size of Supertyphoon Megi (2010) on SST Cooling. Monthly Weather Review. 2018; 146 (3):661-677.
Chicago/Turabian StyleIam-Fei Pun; I.-I. Lin; Chun-Chi Lien; Chun-Chieh Wu. 2018. "Influence of the Size of Supertyphoon Megi (2010) on SST Cooling." Monthly Weather Review 146, no. 3: 661-677.
Hurricane Patricia formed on 20 October 2015 in the Eastern Pacific and, in less than 3 days, rapidly intensified from a Tropical Storm to a record‐breaking hurricane with maximum sustained winds measured around 185 knots. It is almost 15 knots higher than 2013's supertyphoon Haiyan (the previous strongest tropical cyclone (TC) ever observed). This research focuses on analyzing the air‐sea enthalpy flux conditions that contributed to Hurricane Patricia's rapid intensification, and comparing them to supertyphoon Haiyan's. Despite a stronger cooling effect, a higher enthalpy flux supply is found during Patricia, in particular due to warmer pre‐TC sea surface temperature conditions. This resulted in larger temperature and humidity differences at the air‐sea interface, contributing to larger air‐sea enthalpy heat fluxes available for Patricia's growth (24% more than for Haiyan). In addition, air‐sea fluxes simulations were performed for Hurricane Patricia under different climate conditions to assess specifically the impact of local and large‐scale conditions on storm intensification associated with six different phases and types of El Niño Southern Oscillation (ENSO) and long‐term climatological summer condition. We found that the Eastern Pacific El Niño developing and decaying summers, and the Central Pacific El Niño developing summer are the three most favorable ENSO conditions for storm intensification. This still represents a 37% smaller flux supply than in October 2015, suggesting that Patricia extraordinary growth is not achievable under any of these typical ENSO conditions but rather the result of the exceptional environmental conditions associated with the buildup of the strongest El Niño ever recorded.
Hsiao-Ching Huang; Julien Boucharel; I.-I. Lin; Fei-Fei Jin; Chun-Chi Lien; Iam-Fei Pun. Air-sea fluxes for Hurricane Patricia (2015): Comparison with supertyphoon Haiyan (2013) and under different ENSO conditions. Journal of Geophysical Research: Oceans 2017, 122, 6076 -6089.
AMA StyleHsiao-Ching Huang, Julien Boucharel, I.-I. Lin, Fei-Fei Jin, Chun-Chi Lien, Iam-Fei Pun. Air-sea fluxes for Hurricane Patricia (2015): Comparison with supertyphoon Haiyan (2013) and under different ENSO conditions. Journal of Geophysical Research: Oceans. 2017; 122 (8):6076-6089.
Chicago/Turabian StyleHsiao-Ching Huang; Julien Boucharel; I.-I. Lin; Fei-Fei Jin; Chun-Chi Lien; Iam-Fei Pun. 2017. "Air-sea fluxes for Hurricane Patricia (2015): Comparison with supertyphoon Haiyan (2013) and under different ENSO conditions." Journal of Geophysical Research: Oceans 122, no. 8: 6076-6089.
The thermocline shoals in the South China Sea (SCS) relative to the tropical northwest Pacific Ocean (NWP), as required by geostrophic balance with the Kuroshio. The present study examines the effect of this difference in ocean state on the response of sea surface temperature (SST) and chlorophyll concentration to tropical cyclones (TCs), using both satellite-derived measurements and three-dimensional numerical simulations. In both regions, TC-produced SST cooling strongly depends on TC characteristics (including intensity as measured by the maximum surface wind speed, translation speed, and size). When subject to identical TC forcing, the SST cooling in the SCS is more than 1.5 times that in the NWP, which may partially explain weaker TC intensity on average observed in the SCS. Both a shallower mixed layer and stronger subsurface thermal stratification in the SCS contribute to this regional difference in SST cooling. The mixed layer effect dominates when TCs are weak, fast-moving, and/or small; and for strong and slow-moving TCs or strong and large TCs, both factors are equally important. In both regions, TCs tend to elevate surface chlorophyll concentration. For identical TC forcing, the surface chlorophyll increase in the SCS is around 10 times that in the NWP, a difference much stronger than that in SST cooling. This large regional difference in the surface chlorophyll response is at least partially due to a shallower nutricline and stronger vertical nutrient gradient in the SCS. The effect of regional difference in upper-ocean density stratification on the surface nutrient response is negligible. The total annual primary production increase associated with the TC passage estimated using the vertically generalized production model in the SCS is nearly 3 times that in the NWP (i.e., 6.4 ± 0.4 × 1012 versus 2.2 ± 0.2 × 1012 g C), despite the weaker TC activity in the SCS.
Wei Mei; Chun-Chi Lien; I-I Lin; Shang-Ping Xie. Tropical Cyclone–Induced Ocean Response: A Comparative Study of the South China Sea and Tropical Northwest Pacific*,+. Journal of Climate 2015, 28, 5952 -5968.
AMA StyleWei Mei, Chun-Chi Lien, I-I Lin, Shang-Ping Xie. Tropical Cyclone–Induced Ocean Response: A Comparative Study of the South China Sea and Tropical Northwest Pacific*,+. Journal of Climate. 2015; 28 (15):5952-5968.
Chicago/Turabian StyleWei Mei; Chun-Chi Lien; I-I Lin; Shang-Ping Xie. 2015. "Tropical Cyclone–Induced Ocean Response: A Comparative Study of the South China Sea and Tropical Northwest Pacific*,+." Journal of Climate 28, no. 15: 5952-5968.
With the extra‐ordinary intensity of 170 kts, super‐typhoon Haiyan devastated the Philippines in November 2013. This intensity is among the highest ever observed for tropical cyclones (TCs) globally, 35 kts well above the threshold of the existing highest category of 5. Though there is speculation to associate global warming with such intensity, existing research indicate that we have been in a warming hiatus period, with the hiatus attributed to the La Niña‐like multi‐decadal phenomenon. It is thus intriguing to understand why Haiyan can occur during hiatus. It is suggested that as the western Pacific manifestation of the La Niña‐like phenomenon is to pile up warm subsurface water to the west, the western North Pacific experienced evident subsurface warming and created a very favorable ocean pre‐condition for Haiyan. Together with its fast travelling speed, the air‐sea flux supply was 158% as compared to normal for intensification.
I.‐I. Lin; Iam‐Fei Pun; Chun-Chi Lien. “Category‐6” supertyphoon Haiyan in global warming hiatus: Contribution from subsurface ocean warming. Geophysical Research Letters 2014, 41, 8547 -8553.
AMA StyleI.‐I. Lin, Iam‐Fei Pun, Chun-Chi Lien. “Category‐6” supertyphoon Haiyan in global warming hiatus: Contribution from subsurface ocean warming. Geophysical Research Letters. 2014; 41 (23):8547-8553.
Chicago/Turabian StyleI.‐I. Lin; Iam‐Fei Pun; Chun-Chi Lien. 2014. "“Category‐6” supertyphoon Haiyan in global warming hiatus: Contribution from subsurface ocean warming." Geophysical Research Letters 41, no. 23: 8547-8553.
[1] Timely and accurate forecasts of tropical cyclones (TCs, i.e., hurricanes and typhoons) are of great importance for risk mitigation. Although in the past two decades there has been steady improvement in track prediction, improvement on intensity prediction is still highly challenging. Cooling of the upper ocean by TC‐induced mixing is an important process that impacts TC intensity. Based on detail in situ air‐deployed ocean and atmospheric measurement pairs collected during the Impact of Typhoons on the Ocean in the Pacific (ITOP) field campaign, we modify the widely used Sea Surface Temperature Potential Intensity (SST_PI) index by including information from the subsurface ocean temperature profile to form a new Ocean coupling Potential Intensity (OC_PI) index. Using OC_PI as a TC maximum intensity predictor and applied to a 14 year (1998–2011) western North Pacific TC archive, OC_PI reduces SST_PI‐based overestimation of archived maximum intensity by more than 50% and increases the correlation of maximum intensity estimation from r2 = 0.08 to 0.31. For slow‐moving TCs that cause the greatest cooling, r2 increases to 0.56 and the root‐mean square error in maximum intensity is 11 m s−1. As OC_PI can more realistically characterize the ocean contribution to TC intensity, it thus serves as an effective new index to improve estimation and prediction of TC maximum intensity.
I.‐I. Lin; Peter G Black; James F Price; C.‐Y. Yang; Shuyi S Chen; Chun-Chi Lien; Patrick A Harr; N.‐H. Chi; Chun-Chieh Wu; E. A. D'asaro. An ocean coupling potential intensity index for tropical cyclones. Geophysical Research Letters 2013, 40, 1878 -1882.
AMA StyleI.‐I. Lin, Peter G Black, James F Price, C.‐Y. Yang, Shuyi S Chen, Chun-Chi Lien, Patrick A Harr, N.‐H. Chi, Chun-Chieh Wu, E. A. D'asaro. An ocean coupling potential intensity index for tropical cyclones. Geophysical Research Letters. 2013; 40 (9):1878-1882.
Chicago/Turabian StyleI.‐I. Lin; Peter G Black; James F Price; C.‐Y. Yang; Shuyi S Chen; Chun-Chi Lien; Patrick A Harr; N.‐H. Chi; Chun-Chieh Wu; E. A. D'asaro. 2013. "An ocean coupling potential intensity index for tropical cyclones." Geophysical Research Letters 40, no. 9: 1878-1882.
I-I Lin; Eric A D'asaro; Peter Black; James F. Price; Chao-Yuan Yang; Shuyi S. Chen; Chun-Chi Lien; P. A. Harr; Nan-Hsiung Chi; Chun-Chieh Wu. An ocean cooling potential intensity index for tropical cyclones. Geophysical Research Letters 2012, 1 .
AMA StyleI-I Lin, Eric A D'asaro, Peter Black, James F. Price, Chao-Yuan Yang, Shuyi S. Chen, Chun-Chi Lien, P. A. Harr, Nan-Hsiung Chi, Chun-Chieh Wu. An ocean cooling potential intensity index for tropical cyclones. Geophysical Research Letters. 2012; ():1.
Chicago/Turabian StyleI-I Lin; Eric A D'asaro; Peter Black; James F. Price; Chao-Yuan Yang; Shuyi S. Chen; Chun-Chi Lien; P. A. Harr; Nan-Hsiung Chi; Chun-Chieh Wu. 2012. "An ocean cooling potential intensity index for tropical cyclones." Geophysical Research Letters , no. : 1.
[1] In May 2003, a phytoplankton bloom of chlorophyll‐a (Chl‐a) concentration of 0.3–0.4 mgm−3 was observed at the centre of northern South China Sea (SCS) by NASA's Sea‐viewing Wide Field‐of‐View sensor. As this region is remote and known to be oligotrophic in spring (Chl‐a concentration typically at ∼0.05–0.08 mgm−3), it is intriguing to explore this unusual happening. Based on six different remote sensing data and numerical modelling, the results suggest that the injection of an ocean eddy is the most likely cause of the bloom. Due to long‐range transport of a large (700 × 500 km) anti‐cyclonic ocean eddy, coastal nutrients and plankton could be brought across hundreds of kilometres to the centre of northern SCS and impact the biogeochemistry. The open ocean part of the northern SCS basin has long been considered generally free from coastal influences. This work provides new evidence that proves otherwise. Moreover, from the perspective of physical oceanography, it is interesting to observe that, outside the monsoon seasons, there can be well‐defined anti‐cyclonic ocean circulation existing in the SCS without the prevailing monsoonal wind.
I-I Lin; Chun-Chi Lien; Chau-Ron Wu; George T. F. Wong; Chih-Wei Huang; Tzu-Ling Chiang. Enhanced primary production in the oligotrophic South China Sea by eddy injection in spring. Geophysical Research Letters 2010, 37, 1 .
AMA StyleI-I Lin, Chun-Chi Lien, Chau-Ron Wu, George T. F. Wong, Chih-Wei Huang, Tzu-Ling Chiang. Enhanced primary production in the oligotrophic South China Sea by eddy injection in spring. Geophysical Research Letters. 2010; 37 (16):1.
Chicago/Turabian StyleI-I Lin; Chun-Chi Lien; Chau-Ron Wu; George T. F. Wong; Chih-Wei Huang; Tzu-Ling Chiang. 2010. "Enhanced primary production in the oligotrophic South China Sea by eddy injection in spring." Geophysical Research Letters 37, no. 16: 1.
[1] Using 4 years' of aerosol optical thickness (AOT) and chlorophyll‐a (Chl‐a) concentration data from the NASA/MODIS and SeaWiFS sensors, this work systematically explores the role that atmospheric aerosols play in the biogeochemistry of the South China Sea (SCS). The results suggest that the further away from the coastline, the greater the potential role for atmospheric aerosols would be as a nutrient source to stimulate the biological activities because the chances of having other sources of nutrient inputs (e.g., river run‐off or upwelling) are lower. It is found that the highest correlated area (R ∼ 0.7) of the Chl‐a and AOT time series is in the southern centre of the SCS basin, typically between 111–113°E and 8–10°N. Away from the basin centre, the correlation between the two time series is typically low, with R ∼ 0.2–0.3. It is found that since there are other more prominent nutrient sources (e.g., monsoon‐induced upwelling and convective‐overturn) to support the biological activities, atmospheric aerosols become less critical as a nutrient source in regions away from the basin centre.
I.-I. Lin; George T. F. Wong; Chun-Chi Lien; Chin-Ying Chien; Chih-Wei Huang; Jen-Ping Chen. Aerosol impact on the South China Sea biogeochemistry: An early assessment from remote sensing. Geophysical Research Letters 2009, 36, 1 .
AMA StyleI.-I. Lin, George T. F. Wong, Chun-Chi Lien, Chin-Ying Chien, Chih-Wei Huang, Jen-Ping Chen. Aerosol impact on the South China Sea biogeochemistry: An early assessment from remote sensing. Geophysical Research Letters. 2009; 36 (17):1.
Chicago/Turabian StyleI.-I. Lin; George T. F. Wong; Chun-Chi Lien; Chin-Ying Chien; Chih-Wei Huang; Jen-Ping Chen. 2009. "Aerosol impact on the South China Sea biogeochemistry: An early assessment from remote sensing." Geophysical Research Letters 36, no. 17: 1.
Data from the MODerate Resolution Imaging Spectro-radiometer (MODIS) and other satellite sensors in 2002–2004 indicate that, in addition to locally produced sea-salt particles, aerosols from various remote sources also find their ways to the South China Sea, including industrial/urban pollution in eastern China, wind-blown dust from Asian deserts and biomass burning in Sumatra and Borneo. Among these sources, anthropogenic aerosols from eastern China are produced year round while desert dusts are produced primarily between February and April and biomass burning smoke from August to October. In terms of size of aerosols, sea salt and dust predominate the coarse mode while pollution and smoke predominate the fine-mode particles. Our study suggests that the aerosol input to the South China Sea come from different remote sources dependent upon the season, as opposed to a single dust source as previously anticipated. In the winter monsoon season from November to April, the prevailing northeasterly carries anthropogenic aerosols mixed with dust during dust outbreaks to the northern South China Sea. In the summer monsoon season from June to September, the prevailing southwesterly favours the transporting of smoke particles associated with biomass burning in Borneo and Sumatra to the southern South China Sea. The variety of remote aerosol sources associated with strong spatial and temporal variability of transporting aerosols to the region shows the complexity of atmospheric impact on the biogeochemistry in the South China Sea. Hence, an integrated research approach is deemed critical to assess the biogeochemical impact of these aerosols to the South China Sea.
I-I Lin; Jen-Ping Chen; George T.F. Wong; Chih-Wei Huang; Chun-Chi Lien. Aerosol input to the South China Sea: Results from the MODerate Resolution Imaging Spectro-radiometer, the Quick Scatterometer, and the Measurements of Pollution in the Troposphere Sensor. Deep Sea Research Part II: Topical Studies in Oceanography 2007, 54, 1589 -1601.
AMA StyleI-I Lin, Jen-Ping Chen, George T.F. Wong, Chih-Wei Huang, Chun-Chi Lien. Aerosol input to the South China Sea: Results from the MODerate Resolution Imaging Spectro-radiometer, the Quick Scatterometer, and the Measurements of Pollution in the Troposphere Sensor. Deep Sea Research Part II: Topical Studies in Oceanography. 2007; 54 (14-15):1589-1601.
Chicago/Turabian StyleI-I Lin; Jen-Ping Chen; George T.F. Wong; Chih-Wei Huang; Chun-Chi Lien. 2007. "Aerosol input to the South China Sea: Results from the MODerate Resolution Imaging Spectro-radiometer, the Quick Scatterometer, and the Measurements of Pollution in the Troposphere Sensor." Deep Sea Research Part II: Topical Studies in Oceanography 54, no. 14-15: 1589-1601.
The existence of quasi-stationary alongshore atmospheric fronts typically located 30–70 km off the east coast of Taiwan is demonstrated by analyzing synthetic aperture radar (SAR) images of the sea surface acquired by the European Remote Sensing Satellites ERS-1 and ERS-2. For the data interpretation, cloud images from the Japanese Geostationary Meteorological Satellite GMS-4 and the American Terra satellite, rain-rate maps from ground-based weather radars, sea surface wind data from the scatterometer on board the Quick Scatterometer (QuikSCAT) satellite, and meteorological data from weather maps and radiosonde ascents have also been used. It is shown that these atmospheric fronts are generated by the collisions of the two airflows from opposing directions: one is associated with a weak easterly synoptic-scale wind blowing against the high coastal mountain range at the east coast of Taiwan and the other with a local offshore wind. At the convergence zone where both airflows collide, air is forced to move upward, which often gives rise to the formation of coast-parallel cloud bands. There are two hypotheses about the origin of the offshore wind. The first one is that it is a thermally driven land breeze/katabatic wind, and the second one is that it is wind resulting from recirculated airflow from the synoptic-scale onshore wind. Air blocked by the mountain range at low Froude numbers is recirculated and flows at low levels back offshore. Arguments in favor of and against the two hypotheses are presented. It is argued that both the recirculation of airflow and land breeze/katabatic wind contribute to the formation of the offshore atmospheric front but that land breeze/katabatic wind is probably the main cause.
Werner Alpers; Jen-Ping Chen; I-I. Lin; Chun-Chi Lien. Atmospheric Fronts along the East Coast of Taiwan Studied by ERS Synthetic Aperture Radar Images. Journal of the Atmospheric Sciences 2007, 64, 922 -937.
AMA StyleWerner Alpers, Jen-Ping Chen, I-I. Lin, Chun-Chi Lien. Atmospheric Fronts along the East Coast of Taiwan Studied by ERS Synthetic Aperture Radar Images. Journal of the Atmospheric Sciences. 2007; 64 (3):922-937.
Chicago/Turabian StyleWerner Alpers; Jen-Ping Chen; I-I. Lin; Chun-Chi Lien. 2007. "Atmospheric Fronts along the East Coast of Taiwan Studied by ERS Synthetic Aperture Radar Images." Journal of the Atmospheric Sciences 64, no. 3: 922-937.