Wu, Chi-Hua吳奇樺

Associate Research Fellow

Research Interests

My research lies in the field of monsoon, with a longstanding interest in the origin and sensitivity of East Asian seasonality. My projects have, step by step, explored changes in climatology that may be orbitally or anthropogenically driven. The focused researches have improved our understanding of monsoon paleoclimate, climate variability, and future projection. In general, we perform empirical data analysis and climate modeling together to pinpoint process mechanisms of research object, e.g., geographical impact on seasonal dramatic changes, individual and combined effects of orbital parameters, volcanic contribution to seasonal decadal change. Recently, we have been interested in the topic of (monsoon) climate predictability. We may have proposed to understand the extent to which monsoon decadal dynamics might be biased in climate projection.

Representative Publications

Wu, C. H.*P. C. Tsai, W. R. Huang, and S. Y. Wang, (2022): Winter-summer contrast of the 1990s decadal change in relation to Afro-Asian monsoons. Climate Dynamics. https://doi.org/10.1007/s00382-022-06191-7

Wu, C. H.*, S. Y. Lee, and P. C. Tsai, (2021): Role of eccentricity in early Holocene African and Asian summer monsoons. Scientific Reports, 11, 24089https://doi.org/10.1038/s41598-021-03525-z

Wu, C. H.*, (2021): Seasonal adjustment of particulate matter pollution in coastal East Asia during the 2020 COVID lockdown. Environ. Res. Lett., 16, 124023. https://doi.org/10.1088/1748-9326/ac343c

Wu, C. H.*, and P. C. Tsai, (2021): Impact of orbitally-driven seasonal insolation changes on Afro-Asian summer monsoons through the Holocene. Commun Earth Environ 2, 4. https://doi.org/10.1038/s43247-020-00073-8

Wu, C. H.*, and P. C. Tsai, (2020): Obliquity-driven changes in East Asian seasonality. Global and Planetary Change, 189, 103161. https://doi.org/10.1016/j.gloplacha.2020.103161

Wu, C. H.*, P. C. Tsai, and N. Freychet, (2020): Changing dynamical control of early Asian summer monsoon in the mid-1990s. Climate Dynamics, 54(1), 85-98. doi:10.1007/s00382-019-04989-6

Wu, C. H.*, I. C. Tsai, P. C. Tsai, and Y. S. Tung, (2019): Large-scale seasonal control of air quality in Taiwan. Atmospheric Environment, 214, 116868. https://doi.org/10.1016/j.atmosenv.2019.116868

Wu, C. H.*, S. Y. Wang, and H. H. Hsu, (2018): Large-scale control of the Arabian Sea monsoon inversion in August. Climate Dynamics, 51(7), 2581-2592. DOI: 10.1007/s00382-017-4029-7

Wu, C. H.*, S. Y. Lee, and J. C. H. Chiang, (2018): Relative influence of precession and obliquity in the early Holocene: topographic modulation of subtropical seasonality during the Asian summer monsoon. Quaternary Science Reviews, 191, 238-255. https://doi.org/10.1016/j.quascirev.2018.05.021

Wu, C. H.*, M. D. Chou, and Y. H. Fong, (2018): Impact of the Himalayas on the Meiyu-Baiu migration. Climate Dynamics, 50(3), 1307-1319. DOI: 10.1007/s00382-017-3686-x



The role of Indochina Peninsula topography in East Asian seasonality Stage–wise precipitation over East Asia, primarily from spring to summer, is influenced by nearby monsoons and can be topographically driven. Our modeling works pointed to the role of the topographical processes of the Indochina Peninsula in driving the rapid monsoonal transitions, which correspond to the early summer vertical circulation coupling over the Bay of Bengal–Indochina Peninsula and the late–July WNP monsoon onset. Therefore, asymmetric characteristics of East Asian seasonality could be partly attributed to the existence of Indochina Peninsula.

Decadal climate changes The present-day monsoon area may have expanded in timescales of short-term climate, and in some regions the result is comparable with paleoclimate records. It is instructive to understand how sensitive of the large-scale dry-wet patterns to climate variability and even macroclimate change. Whether decadal changes could be considered a changing climatology may be a further challenge. In the 1990s, observations have confirmed a changing dynamical control of the Asian summer monsoon, with a novel insight into a growing midlatitude influence on the early Asian summer monsoon; with this regard, the continental thermal control as thought a dominant driver of summer monsoon can be comparable.

Seasonal perspective on the role of precession and obliquity in the early Holocene On orbital timescales, higher summer insolation is thought to strengthen the continental monsoon while weakening the maritime monsoon in the northern hemisphere. Presently, interior Asian continental heating drives the South and East Asian monsoons in late spring–early summer. The broad-scale monsoonal circulation further expands zonally in July–August, corresponding to the development of summer monsoons in West Africa and oceanic regions. Tropical and oceanic heating becomes crucial in late summer. With this seasonal regard, our modeling results suggested that precession dominates the atmospheric heating change over the Tibetan Plateau–Himalayas and Maritime Continent, whereas obliquity is responsible for the heating change over the equatorial Indian Ocean. Thus, precession and obliquity can play contrasting roles in driving the monsoons on orbital timescales.

Coordinated evolution of the Holocene Afro–Asian summer monsoons The asynchronous Holocene evolution of Afro–Asian summer monsoons provides valuable insight into climate dynamics and changes. Although still a matter of debate, monsoons changed somewhat abruptly in the mid-Holocene. By investigating data–model synthesis, with the major focus on the differential seasonal responses of solar insolation and monsoons to orbital changes, we observed coordinated and stepwise seasonal evolution of summer monsoons across the mid-Holocene. Prior to the mid-Holocene, insolation had decreased considerably during the early summer; the continental monsoons migrated southeastward, which corresponded to a more pronounced rainy season in coastal East Asia. By contrast, late-summer insolation did not decrease until the mid-Holocene. The continued weakening of the continental monsoons, combined with weakened insolation, accelerated a large-scale migration of monsoons.

  • Ph.D.
    Atmospheric Sciences
    National Taiwan University, Taiwan (2010)
  • B.S.
    Earth Sciences
    National Taiwan Normal University, Taiwan (2001)
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