本研究中，我們分析了北臺灣三個地點：臺北、鞍部及彭佳嶼的冬季長期資料(2008-2017年)。主要研究目的是利用Mann-Kendall檢定法及Sen斜率推估法，以雨水採樣品中無機成分之濃度特徵，探討這些採樣點的降水化學特性、時空分布上的長期趨勢與降雨類型對雨水採樣的影響。
在這段分析期間，臺北、鞍部及彭佳嶼的平均雨水酸鹼值分別為4.91、4.73和4.70，而雨水樣品的酸鹼值主要與NO3-、nss-SO42-、NH4+、K+、Mg2+和Ca2+等有密切相關。長期趨勢發現總體酸鹼值有上升趨勢，此現象可歸因於Ca2+增加，而鞍部、彭佳嶼兩處nss-SO42-之濃度下降也可能使雨水酸鹼值下降，但臺北則因都市排放而有不同變化；由於採樣位置差異及降水性不同，使得彭佳嶼的海鹽離子、NO3-和nss-SO42-均高於另外兩個採樣點。
此外，人為排放的變化與氣團在區域傳輸的狀態也會影響分析結果。而不同的降水類型議會影響化學分析結果，由東北季風所帶來的降水，其樣品中的離子濃度會較鋒面系統所引起的降水來得大，但數值差異不大，因此可推測影響降雨化學的主因來自於人為活動。最後，透過Ca2+的分析結果，可將事件分為兩類：96%為長程傳輸與人為排放混合事件，以及4%的單純沙塵傳送事件。霾害事件則在當中扮演重要角色，因其對於人為排放的垂直混合具有負面影響。

In this study, the long-term (2008-2017) winter precipitation chemistry at three sites in northern Taiwan, including Pengjia islet, Anbu, and Taipei, was analyzed. The major aims of this study are: report the characterization of inorganic component concentrations in rainwater, discuss the spatial distribution, and evaluate the long-term trends of the precipitation chemistry and the effect of weather type on rainfall composition at these sampling locations. The Mann-Kendall test and Sen’s estimation of the slope were employed to detect the long-term trends. Over the entire period, a mean pH of 4.91, 4.73, and 4.70 was found at Taipei, Anbu, and Pengjia islet, respectively. pH of the rainwater samples was strongly related to the concentration of NO3-, non-sea-salt (nss-) SO42- and acid-neutralizing compounds such as NH4+, K+, Mg2+, and Ca2+. Sea salt ions, NO3-, and nss-SO42- were all higher at Pengjia islet than Anbu and Taipei. This can, in part, be explained by the difference in sampling location as well as characteristics of the precipitation. Long-term trends in the precipitation chemistry indicated a significant increase in pH at all sites and could be attributed to a significant increase in Ca2+. At Pengjia islet and Anbu, the decrease in nss-SO42- concentration may have also contributed to the increase in pH, while Taipei showed a different pattern likely due to the impact of local emission. In addition, changes in anthropogenic emissions and the regional transport pattern of air masses may have contributed as well, impacting the precipitation chemistry at all three sites. Rainfall type also contributed to the difference in precipitation chemistry. Precipitation caused by the North-east monsoon (NE) showed a greater ion concentration than precipitation caused by frontal systems (FS) because of the lower precipitation amount in the former. Even so, the contribution fraction of major ions was similar between precipitation stemming from these two types of weather systems, suggesting similar anthropogenic emission sources during both. Effects on precipitation chemistry from the long-range transport of dust at Anbu was assessed through examining high Ca2+ events analysis. Two types of events are classified: 96% of events are associated with the mixing of dust and anthropogenic emission during transport and 4% of events may be considered as pure dust transportation. A haze event can be considered as a factor contributing to the difference between the two event types because of its negative effect on vertical mixing of anthropogenic emissions.

Acid deposition monitoring network in East Asia (EANET). 2016: Third periodic reported on the state of acid deposition in East Asia, part 3 executive summary. ISSN 2432-8324.
Acid deposition monitoring network in East Asia (EANET). 2016: Third periodic reported on the state of acid deposition in East Asia, part 2 national assessments. ISSN 2432-8324.
An integrated assessment; National Acid Precipitation Program (NAPP) report to congress, National Science and Technology Council, 2005.
Andreae, M.O., 2009: Correlation between cloud condensation nuclei concentration and aerosol optical thickness in remote and polluted regions. Atmos. Chem. Phys. 9, 543-556.
Beverland, I.J., Crowther, J.M., Srinivas, M.S.N., Heal, M.R. 1998: The influence of meteorology and atmospheric transport patterns on the chemical composition of rainfall in South-East England. Atmos. Environ. 32, 1039–1048.
Bhatti, N. 1992: Acid rain in asia. Environ. Manag. 16, 541-562.
Calvo, A.I., Pont, V., Olmo, F.J., Castro, A., Alados-Arboledas, L., Vicente, A.M., Fernández-Raga, M., Fraile, R. 2012: Air masses and weather types: a useful tool for characterizing precipitation chemistry and wet deposition. Aerosol and Air Quality Research 12, 856-878
Chang, Ken-Hui., Jeng, Fu-Tien., Tsai, Ya-Ling., Lin, Pay-Liam. 2000: Modeling of long-range transport on Taiwan’s acid deposition under different weather conditions. Atmospheric Environment 34, 3281-3295.
Charron, A., Plaisance, H., Sauvage, S., Coddeville, P., Galloo, J. C., & Guillermo, R. 2002: A study of the source-receptor relationships influencing the acidity of precipitation collected at a rural site in France. Atmos. Environ., 34, pp. 3665-3674.
Cheng, Yu-Chih., Liang, Chi-Sung., Syu, Jin-Yuan., Chang, Yuan-Yi., Yan, Yeou-Lih., Chen, Shui-Jen., Chen, Chih-Chieh., Lin, Wen-Yinn. 2015: Characteristics of Aerosol Extinction Coefficient in Taipei Metropolitan Atmosphere. Aerosol and Air Quality Research, 15, 1823–1835.
Chuang, Ming-Tung., Chang, Shuenn-Chin., Lin, Neng-Huei., Wang, Jia-Lin., Sheu, Guey-Rong., Chang, You-Jia., Lee, Chung-Te. 2013: Aerosol chemical properties and related pollutants measured in Dongsha Island in the northern South China Sea during 7 SEAS/Dongsha Experiment. Atmospheric Environment. 78, 82 – 92.
Chuang, Ming-Tung., Lee, Chung-Te., Charles C.-K. Chou., Lin, Neng-Huei., Sheu, Guey-Rong., Wang, Jia-Lin., Chang, Shuenn-Chin., Wang, Sheng-Hsiang., Chi, Kai Hsien., Young , Chea-Yuan., Huang Hill., Chen, Horng-Wen., Weng, Guo-Hau., Lai, Sin-Yu., Hsu, Shao-Peng., Chang, Yu-Jia., Chang, Jia-Hon., Wu, Xyue-Chang. 2014: Carbonaceous aerosols in the air masses transported from Indochina to Taiwan: Long-term observation at Mt. Lulin. Atmospheric Environment,89, 507-516
Chung, Y.S., Kim, T.K., Kim, K.H. 1996: Temporal variation and cause of acidic precipitation from a monitoring network in Korea, Atmos. Environ. 30, 2429-2435.
Chung-Te Chang, Chiao-Ping Wang, Jr-Huang Chuan, Lih-Jih Wang, Chiung-Pin Liu, LinTeng-Chiu. 2017: Trends of two decadal precipitation chemistry in a subtropical rainforest in East Asia. Science of the Total Environment, 605–606, 88–98.
Das, S.K., Jayaraman, A., 2012: Long-range transportation of anthropogenic aerosols over
eastern coastal region of India: investigation of sources and impact on regional climate change. Atmos. Res. 118, 68–83.
Dayan, U., Lamb, D. 2003: Meteorological indicators of summer precipitation chemistry in Central Pennsylvania. Atmos. Environ. 37, 1045–1055.
Duan, L., Yu, Q., Zhang, Q., Wang, Z., Pan, Y., Larssen, T., Tang, J., Mulder, J. 2016: Acid deposition in Asia: Emissions, deposition, and ecosystem effects Atmos. Environ., 146, pp. 55-69
Fowler, D., Pilegaard, K., Sutton, M.A., Ambus, P., Raivonen, M., Duyzer, J., Simpson, D., Fagerli, J., Fuzzi, S., Schjoerring, J.K., Granier, C., Neftel, A., Isaksen, I.S.A., Laj, P., Maione, M., 2009: Atmospheric composition change: ecosystems-atmosphere interactions. Atmos. Environ. 43, 5193–5267.
Fu, Congbin and X. Teng, 1988: The relationship between ENSO and climate anomaly in China during the summertime. Scientia Atmospherica Sinica, Special Issue, 133-141
Fujita, Shin-ichi., Takahashi, Akira., Wen, Jian-Hua., Huan, Lian-Fen., Kim, Hui-Kang., Li, Cheng Kang., Huang, Frank T.C.., Jeng, Fu-Tien. 2000: Precipitation chemistry in East Asia. Atmospheric Environment 34, 525-537.
Galloway, J.N. and Gaudry, A. 1984: The Composition of Precipitation on Amsterdam Island, Indian Ocean. Atmos. Environ. 18: 2649–2656.
Galloway, J.N., Likens, G.E., Keene, W.C., Miller, J.M. 1982: The composition of precipitation in remote areas of the world. Journal of Geophysical Research 87, 8771-8786.
Galloway, J.N., Zhao, D.W., Xiong, J.L., Likens, G.E. 1987: Acid rain: China, United States and a remote area. Science 236, 1559-1962.
Gong Hainan., Lin Wang., Wen Zhou., Wen Chen., Renguang Wu., Lin Liu., Debashis Nath., and Marco Y.-T. Leung. 2018: Revisiting the Northern Mode of East Asian Winter Monsoon Variation and Its Response to Global Warming. American Meteorological Society. 31, 9001-9014.
Hara, H. 1997: Precipitation chemistry in Japan, Chem. Soc. Jpn. 11, 733-748.
Hara, H., Kitamura, M., Mori, A., Noguchi, I., Ohizumi, T., Seto, S., Takeuchi, T., Deguchi, T. 1995: Precipitation chemistry in Japan 1989–1993. Water Air Soil Pollut. 85, 2307 2312.
Huang Kan., Zhuang Guoshun., Xu Chang., Wang Ying., Tang Aohan. 2008: The chemistry of the severe acidic precipitation in Shanghai, China. Atmospheric Research. 89, 149–160.
Huang, Ronghui and Y. Wu, 1989: The influence of ENSO on the summer climate change in China and its mechanisms. Adv. Atmos. Sci., 6, 21
Itahashi, S., Uno, I., Hayami, H., and Fujita, S. 2015: variation of the ratio of nitrate to non-seasalt sulfate in precipitation over East Asia with emissions from China, Atmos. Environ., 118, 87–97.
Itahashi, S., Yumimoto, K., Uno, I., Hayami, H., Fujita, S.-I., Pan, Y., and Wang, Y. 2018: A 15-year record (2001–2015) of the ratio of nitrate to non-sea-salt sulfate in precipitation over East Asia. Atmos. Chem. Phys., 18, 2835-2852.
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deavan, D., Iredell, M., Saha, S., White, G., Woolen, J., Zhu, Y., Leetmaa, A., Reynolds, R., Chelliah, M., Ebisuzaki, W., Higgins, W., Janowiak, H., Mo, K.C., Ropelewski, C., Wang, J., Jenne, R., Joseph, D. 1996: The NCEP/NCAR 40-year reanalysis project. Bulletin of the American Meteorological Society 77, 437-471.
Keene, W.C., Pszenny, A.A.P., Galloway, J.N., Hawley, M.E. 1986: Sea-salt corrections and interpretation of constituent ratios in marine precipitation. J. Geophys. Res. 91 (D6), 6647-6658
Klemm, Otto and Lin, Neng¬-Huei. 2016; What Causes Observed Fog Trends: Air Quality or Climate Change? Aerosol and Air Quality Research, 16: 1131–1142.
Klemm, Otto., Tseng, Wei-Ti., Lin, Chia-Ching., Kerstin I. Klemm., Lin, Neng-Huei (George). 2015: pH Control in Fog and Rain in East Asia: Temporal Advection of Clean Air Masses to Mt. Bamboo, Taiwan. Atmosphere, 6, 1785-1800.
Kuo, Pei-Hsuan & Tsuang, Ben-Jei. 2005: Successful air quality management program in central Taiwan. Atmospheric Sciences and Air Quality Conferences, Session 9, Air Quality programs.
Lee, B., Hong, S., Lee, D., 2000: Chemical composition of precipitation and wet deposition of major ions on the Korean peninsula. Atmospheric Environment. 34, 563–575
Lee, B.K., Hong, S.H., Lee, D.S. 2000: Chemical composition of precipitation and wet deposition of major ions on the Korean peninsula. Atmos. Environ. 34, 563–575.
Lee Chung-Te, Chuang Ming-Tung, Lin Neng-Huei, Wang Jia-Lin, Sheu Guey-Rong, Chang Shuenn-Chin, Wang Sheng-Hsiang, Huang Hill, Chen Horng-Wen, Liu Yuan-Liang, Weng Guo-Hau, Lai Hsin-Yo, Hsu Shao-Peng. 2011: The enhancement of PM2.5 mass and water-soluble ions of biosmoke transported from Southeast Asia over the Mountain Lulin site in Taiwan. Atmospheric Environment, 45, 5784-5794.
Li Jia, Mihály Pósfai, Peter V. Hobbs, Peter R. Buseck. 2003: Individual aerosol particles from biomass burning in southern Africa: Compositions and size distributions of carbonaceous particles, Journal of geophysical research. Vol. 108, No. D13, 8483.
Li, Y., XL, Y., Cheng, H.B., Lin, W.L., Tang, J., Wang, S.F. 2010: Chemical characteristics of precipitation at three Chinese regional background stations from 2006 to 2007. Atmos. Res. 96, 173–183.
Lin, Neng¬-Huei and Peng, Chi-Ming. 1999: Estimates of the contribution of Below-cloud Scavenging to the Pollution loadings of Rain in Taipei, Taiwan. Tao, vol.10, no.4, 693-704.
Lin, Neng¬-Huei., Lee H.-M., Chang M.-B. 1999: Evaluation of the characteristics of acid precipitation in Taipei, Taiwan using cluster analysis. Water, Air, and Soil Pollution, 113, 241–260.
Lynch, J.A., Bowersox, V.C., Grimm, J.W. 2000: Changes in sulfate deposition in eastern U.S. following implementation of phase I of title IV of the clean air act amendments of 1990. Atmos. Environ. 34, 1665-1680
Marchetto, A., Rogora, M., Arisci, S., 2013: Trend analysis of atmospheric deposition data: a comparison of statistical approaches. Atmos. Environ. 64, 95-102.
Marinoni A, Laj P, Sellegri K & Mailhot G. 2004: Cloud chemistry at the Puy de Dome: variability and relationships with environmental factors. Atmos Chem Phys 4: 715–728
Monks, P.S., Granier, C., Fuzzi, S., Stohl, A., Williams, M.L., Akimoto, H., Amann, M.,
Baklanov, A., Baltensperger, U., Bey, I., Blake, N., Blake, R.S., Carslaw, K., Cooper, O.R., Dentener, F., Fowler, D., Fragkou, E., Frost, G.J., Generoso, S., Ginoux, P., Grewe, V., Guenther, A., Hansson, H.C., Henne, S., Hjorth, J., Hofzumahaus, A., Huntrieser, H., Isaksen, I.S.A., Jenkin, M.E., Kaiser, J., Kanakidou, M., Klimont, Z., Kulmala, M., Laj, P., Lawrence, M.G., Lee, J.D., Liousse, C., Maione, M., McFiggans, G., Metzger, A., Mieville, A., Moussiopoulos, N., Orlando, J.J., O’Dowd, C.D., Palmer, P.I., Parrish, D.D., Petzold, A., Platt, U., Poschl, U., Prevot, A.S.H., Reeves, C.E., Reimann, S., Rudich, Y., Sellegri, K., Steinbrecher, R., Simpson, D., ten Brink, H., Theloke, J., van der Werf, G.R., Vautard, R., Vestreng, V., Vlachokostas, C., von Glasow, R., 2009. Atmospheric composition change - global and regional air quality. Atmos. Environ. 43 (33), 5268 - 5350
Okuda, T., Iwase, T., Uedaa, H., Suda, Y., Tanaka, S., Dokiya, Y., Fushimi, K., Hosoe, M., 2005: Long-term trend of chemical constituents in precipitation in Tokyo metropolitan area, Japan, from 1990 to 2002. Science of the Total Environment. 339, 127–141.
Pani, Shantanu Kumar., Lee, Chung-Te., Charles., Chou, C.-K., Shimada Kojiro., Hatakeyama Shiro., Takami Akinori., Wang, Sheng-Hsiang., Lin, Neng-Huei. 2017: Chemical Characterization of Wintertime Aerosols over Islands and Mountains in East Asia: Impacts of the Continental Asian Outflow. Aerosol and Air Quality Research, 17: 3006–3036.
Pascaud, A., Sauvage, S., Coddeville, P., Nicolas, M., Croisé, L., Mezdour, A., Probst, A. 2016: Contrasted spatial and long-term trends in precipitation chemistry and deposition fluxes at rural stations in France. Atmos. Environ., 146, pp. 28-43.
Pathak, R.K., Wu, W.S., Wang, T., 2009: Summertime PM2.5 ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere. Atmos. Chem. Phys. 9, 1711–1722.
Pu Weiwei., Quan Weijun., Ma Zhiqiang., Shi Xuefeng., Zhao Xiujuan., Zhang Linna.,
Wang Zhenfa., Wang Wenyan. 2017: Long-term trend of chemical composition of atmospheric precipitation at a regional background station in Northern China. 580, 1340-1350.
Rodhe, H., F. Dentener, and M. Schulz. 2002: The global distribution of acidifying wet deposition, Environ. Sci. Tech., 36, 4382–4388.
Schindler, D.W. 1988: Effects of acid rain on freshwater ecosystems. Science, 239, 149-157.
Schwede, D.B., Lear, G.G. 2014: A novel hybrid approach for estimating total deposition in the United States. Atmospheric Environment, 92, pp. 207-220.
Seinfeld, J.H, and Pandis, S.N. 2005: Atmospheric chemistry and Physics, from air pollution to climate change, second edition, 954.
Sheu, Guey-Rong., Lin, Neng-Huei. 2011: Mercury in cloud water collected on Mt. Bamboo in northern Taiwan during the northeast monsoon season. Atmospheric Environment 45, 4454-4462.
Sheu, Guey-Rong., Lin, Neng-Huei. 2013: Characterizations of wet mercury deposition to a remote islet (Pengjiayu) in the subtropical Northwest Pacific Ocean. Atmospheric Environment 77, 474-481.
Simon Stefan., Klemm Otto., Madany, Tarek El., Oschka, J Walk., Amelung Katharina., Lin, Po Hsiung., Chang, Shih-Chieh., Lin, Neng-Huei., Engling Guenter., Hsu, Shih-Chieh., Wey, Tsong-Huei., Wang, Ya-Nan., Lee,Yu-Chi. 2016: Chemical Composition of Fog Water at Four Sites in Taiwan. Aerosol and Air Quality Research, 16: 618–631.
Stein, A.F., Draxler, R.R., Rolph, G.D., Stunder, B.J.B., Cohen, M.D., and Ngan, F. 2015: NOAA's HYSPLIT atmospheric transport and dispersion modeling system. Bull. Am. Meteor. Soc., 96, pp. 2059-2077.
Streets, D. G., Bond, T. C., Carmichael, G. R., Fernandes, S. D., Fu, Q., He, D., Klimont, Z., Nelson, S. M., Tsai, N. Y., Wang, M. Q., Woo, J.-H., and Yarber, K. F. 2003: An inventory of gaseous and primary aerosol emissions in Asia in the year 2000. J. Geophys. Res., 108(D21), 8809.
Tang, A., Zhuang, G., Wang, Y., Yuan, H., Sun, Y. 2005: The chemistry of precipitation and its relation to aerosol in Beijing. Atmospheric Environment, 39, 3397-3406.
Tanner, P.A. 1999: Analysis of Hong Kong daily bulk and wet deposition data from 1994 to 1995. Atmos. Environ. 33, 1757–1766.
Tanner, P.A., Won, A.Y.S., 2000: Soluble trace metals and major ionic species in the bulk deposition and atmosphere of Hong Kong. Water Air Soil Pollut. 122, 261–279.
Valenzuela and Kingsmill. 2017: Terrain-Trapped Airflows and Orographic Rainfall along the Coast of Northern California. Part I: Kinematic Characterization Using a Wind Profiling Radar. American Meteorological Society, 145, 2993-3008.
Varma, G.S. 1989: Background trends of pH of precipitation over India. Atmos. Environ. 23, 747-751.
Vet, R., Artz, R.S., Carou, S., Shaw, M., Ro, C.-U., Aas, W., Baker, A., (...), Reid, N.W. 2014: A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus. Atmospheric Environment, 93, pp. 3-100.
Wai, K. M., N.-H. Lin, S.-H. Wang, and Y. Dokiya. 2008: Rainwater chemistry at a high-altitude station, Mt. Lulin, Taiwan: Comparison with a background station, Mt. Fuji, J. Geophys. Res., 113, D06305, doi:10.1029/2006JD008248.
Wang Jiandong., Wang Shuxiao., Jiang Jingkun., Ding Aijun., Zheng Mei., Zhao Bin., Wong, David.C., Zhou Wei., Zheng Guangjie., Wang Long., Jonathan E Pleim., Hao Jiming. 2014: Impact of aerosol–meteorology interactions on fine particle pollution during China’s severe haze episode in January 2013. Environ. Res. Lett. 9, 094002 (7pp).
Wang, S.X., Zhao, B., Cai, S.Y., Klimont, Z., Nielsen, C.P., Morikawa, T., Woo, J.H., Kim, Y., Fu, X., Xu, J.Y., Hao, J.M., He, K.B., 2014: Emission trends and mitigation options for air pollutants in East Asia. Atmos. Chem. Phys. 14, 6571 - 6603.
Wang, Sheng-Hsiang., Lin, Neng-Huei., OuYang, Chang‐Feng ., Wang, Jia‐Lin., James R. Campbell., Peng, Chi-Ming, Lee, Chung-Te., Sheu, Guey-Rong., Tsay, Si‐Chee. 2010: Impact of Asian dust and continental pollutants on cloud chemistry observed in northern Taiwan during the experimental period of ABC/EAREX 2005. Journal of geophysical research. Vol 115, D00K24.
Willey, J.D., Kieber, R.J., Brooks Avery, G. 2006: Changing chemical composition of precipitation in Wilmington, North Carolina, U.S.A. Environ. Sci. Technol. 40, 5675–5680.
Wu, C.C., Kou, W.S., Yang, C.S., 1991. A study on long-range transport of air pollutants over East Asia. Proc. 8th Conf. Air Pollut. Control and Technol., Taipei, Taiwan, pp. 277-287.
Xie Yuanyuan., Ye Xingnan., Ma Zhen., Tao Ye., Wang Ruyu., Zhang Ci., Yang Xin., Chen Jianmin., and Chen Hong. 2017: Insight into winter haze formation mechanisms based on aerosol hygroscopicity and effective density measurements. Atmos. Chem. Phys., 17, 7277 7290
Yang Yiru., Liu Xingang., Qu Yu., Wang Jingli., An Junling., Zhang Yuanhangi., Zhang Fang. 2015, Formation mechanism of continuous extreme haze episodes in the megacity Beijing, China, in January 2013. Atmospheric Research. 155,192–203.
Yin, Zhicong and Wang, Huijun. 2017: Role of atmospheric circulations in haze pollution in December 2016. Atmos. Chem. Phys., 17, 11673–11681.
Zhang Xiuying., Zhao Limin., Cheng Miaomiao., Liu Hongling., Wang Zhen., Wu Xiaodi., Yu Hua. 2018: Long-term changes in wet nitrogen and sulfur deposition in Nanjing. Atmospheric Environment, 195,104–111.
Zhao, D.W., Sun, B.Z.1986: Air pollution and acid rain in China. Ambio 15, 2-5
Zhao, D.W., Xiong, J.L., Xu, Y., Chan, W.H. 1988: Acid-rain in Southwestern China. Atmos. Environ. 22, 349– 358.
Zhaojie Yu, Shiming Wan, Christophe Colin, Hong Yan, Lucile Bonneau, Zhifei Liu, Lina Song, Hanjie Sun, Zhaokai Xu, Xuejun Jiang, Anchun Li, Tiegang Li. 2016: Co-evolution of monsoonal precipitation in East Asia and the tropical Pacific ENSO system since 2.36 Ma: New insights from high-resolution clay mineral records in the West Philippine Sea. Earth and Planetary Science Letters 446, 45–55.