
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 evolution of East Asian seasonality. Our studies have concentrated on the monsoon paleoclimate (orbital-scale change), climate variability, and future projections. In general, we use empirical data analysis and climate modeling to pinpoint the process mechanisms of research objects such as geographical impact on seasonal dramatic changes, individual and combined effects of orbital parameters, and volcanic contribution to seasonal decadal change.
The targeted projects have recently shifted to focus more on the coexistence and changes of the monsoon, Hadley circulation, and Walker circulation, as well as the extent to which extratropical perturbations would contribute. We investigated whether the changes were caused by natural or anthropogenic factors. The general challenge is to determine how sensitive the studied regional seasonal climate issues are when compared to a global zonal mean. We've also become interested in the sensitivity of climate distribution, with the goal to enhance understanding of climate predictability and climate change attribution (bias).
Representative Publications
Wu, C. H.*, and P. C. Tsai, (2025): East Asian synoptic climatology linked to Atlantic multidecadal variability. J Environ Manage, 373, 123549. https://doi.org/10.1016/j.jenvman.2024.123549
Wu, C. H.*, S. Y. Lee, J. C. H. Chiang, and P. C. Tsai, (2023): Role of precession on the transition seasons of the Asian monsoon. npj Clim Atmos Sci, 6, 95. https://doi.org/10.1038/s41612-023-00426-y
Wu, C. H.*, C. J. Shiu, Y. Y. Chen, I. C. Tsai, and S. Y. Lee, (2023): Climatological changes in East Asian winter monsoon circulation in a warmer future. Atmospheric Research, 284, 106593. https://doi.org/10.1016/j.atmosres.2022.106593
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, 59, 1969-1980. 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. Sci Rep, 11, 24089. https://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. https://doi.org/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. https://doi.org/10.1007/s00382-010-0879-y
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. https://doi.org/10.1007/s00382-017-3686-x
Wu, C. H.*, (2017): Thermodynamic and dynamic influences in the Far East-Okhotsk region on stagnant Meiyu-Baiu. J. Geophys. Res. Atmos, 122, 7276-7288. https://doi.org/10.1002/2017JD026558
Highlights
We explored Topographic effects over Asian monsoon region.
We indicated substantial effects of mesoscale mountains on large-scale seasonal characteristics;
We demonstrated remote controls of the seasonal Meiyu–Baiu evolution, including the contribution of the Himalayas and the Far East-Okhotsk region;
We learned that the obliquity contribution to the monsoon changes might be crippled because of the existence of the Tibetan Plateau and Maritime Continent;
We considered the Tibetan Plateau mechanical effect on 'northerly' as a driving factor of East Asian summer monsoon—a complementary thought to the southerly mechanical effect;
We indicated inevitable drawbacks when the Asian monsoon is simulated at a horizontal resolution that is too low to resolve topographic effects and sub-grid processes.
Paleo-monsoon evolution in response to orbital changes | How to determine seasonal dynamics and the extent to which Milankovitch timescales (eccentricity, precession, and obliquity) may be dominant remain debated, despite evidence from multiple paleoclimate proxy records and numerical modeling firmly establishing monsoon changes on orbital scales. We aided in understanding these two bottlenecks by conducting a series of data-model synthesis studies:
Over Afro–Asia–Pacific region, the contribution of obliquity in late summer (with tropical/oceanic origin) can be comparable to the inland/highland origin of precessional control. Some obliquity-driven changes weaken and even disappear when greenhouse gases concentrations increase.
With a superimposed effect of precession, the eccentricity-induced "dry-gets-wetter" condition could be related to the Green Sahara. Over the western Pacific, the tropical response to eccentricity may have been competitive in terms of what an extremely high obliquity could have caused.
We observed the coevolution of Holocene Afro–Asian summer monsoons and proposed an orbitally-related mechanism for the abrupt change in the middle Holocene; the mechanism adequately interprets the seasonal evolution of continental and maritime paleo-monsoons.
We explored how precession affects the transitional seasons of boreal spring and autumn. Strong precessional influence on Earth's glacial–interglacial cycles may lead to a quasi-stationarity of the oceanic monsoon.
Decadal change and predictability:
We investigated the South Asian high decadal changes and provided atypical insight into a growing midlatitude influence on the early Asian summer monsoon in the mid-1990s; in this regard, the continental thermal control, which was previously thought to be the primary driver of summer monsoons is comparable.
With a focus on decadal changes in global dry–wet patterns in seasons, we figured out why the mid-1990s changes happened so rapidly in winter and late spring. We investigated how much the Atlantic Multidecadal Oscillation (AMO) influenced historical macro weathers in East Asia, as a precursor or forcing on decadal changes. We considered AMO-related changes as a function of any driver, regardless of the cause. The dynamical links between the AMO and winter cold surges (and summer typhoons) climate distribution were investigated.timescales.
(02) 2787-5934
chhwu