Holocene East Asian Summer Monsoon Rainfall Variability in Taiwan

Abstract

Characterizing the spatiotemporal variability of the East Asian summer monsoon (EASM) advances our understanding of its rhythm, dynamics, and future impacts. East Asian summer monsoon variations during the Holocene have been reconstructed from a variety of geological archives and proxies. However, the spatiotemporal heterogeneity of EASM rainfall during the Holocene remains controversial. Taiwan is geographically suitable for studying the EASM history, through its geological archives. Herein, we synthesize the reported lake and peat sedimentary records of the entire Holocene, in addition to the records of mass-wasting and on-land deposition from cores collected from Taiwan to illustrate the EASM induced hydroclimate changes in Taiwan throughout the Holocene. Records from Taiwan indicate that the EASM rainfall maximum occurred during the early Holocene, concurring with other EASM records from monsoon regions in southern China. We suggest that the early Holocene EASM rainfall maximum in southern China was mainly forced by the higher Northern Hemisphere summer insolation and sea surface temperatures (SSTs) in the Western Pacific Warm Pool (WPWP). A synthesis of EASM rainfall records from across China shows that the timing of the Holocene EASM rainfall maximum occurred progressively later than that from southern to northern China. This time-transgressive EASM rainfall maximum may be due to the latitudinal shift of the westerlies and Western Pacific subtropical high (WPSH) that was induced by changes of interhemispheric temperature gradients (T N−S) and the northern high latitude ice volume. Moreover, records from Taiwan suggest a significant collapse of the EASM in Taiwan at ∼4-2 ka BP. Based on the records from Taiwan, coastal East Asia, and the Tropical Pacific, we propose that the SSTs of the WPWP and/or El Niño-Southern Oscillation activity may have exerted a strong influence on the EASM rainfall changes during the late Holocene. Moreover, increased EASM rainfall in southern China during the last 2 ka was likely caused by a southward shift of WPSH, which is associated with gradual decreases in T N−S during the late Holocene.

Facies variations in response to tectonic evolution, climate and sea-level changes since the Late Cretaceous in Wuhu region, Eastern China

“…in sea level (Figure 9). The increase in Mz and L* during the period 8.2-11.55 ka BP with the SST and PJJA records (Ding et al, 2020) suggests that the regional sedimentary record during this period is less sensitive to the effects of global climate change, but can still reflect solid climatic fluctuations. The early part of MIS 1 (8.75-11.55 ka BP) has a warmer and wetter climate and can be identified as a period of marginal beach deposition and floodplain accretion.…”

“…In addition, combined with climate-sea level change records, precipitation, temperature, and sporulation records from Chaohu Lake (Wang et al, 2008) are found around 8.75 ka BP, indicating the onset of a rapid temperature rise synoptic event at this time and a significant sea level rise in eastern China (Zheng, 2018), consistent with regional alluvial phase deposition under strong hydrodynamic conditions. In contrast, the d 18 O of NGRIP, d 18 O of Dongge Cave, SST, and PJJA records highlight the Younger Dryas impact hypothesis event at 11.2 ka BP, with a sharp drop in temperature, with cold-dry climate and a brief drop in sea level (Zhang et al, 2004;Praetorius et al, 2015;Ding et al, 2020;Walczak et al, 2020).…”

Correspondence of Drought Occurrences at Multi‐Temporal Scales Between North China and Upper Hanjiang River

“…The precipitation in most parts of China is influenced by the Asian monsoon (divided into two subsystems, the East Asian Monsoon and the Indian Monsoon), especially the East Asian summer monsoon (Ding et al, 2008). NC and the UH are located in the main rain bands of the East Asian summer monsoon; the advance and retreat of the East Asian summer monsoon are accompanied by the movement of the rain bands, which influences the changes in precipitation, droughts and floods in NC and the UH (Ding et al, 2020). It was found that during the period of the 1950s-1970s, when the East Asian summer monsoon was abnormally strong, China's rain bands moved northwards, and NC was relatively wet; after the late 1970s, the East Asian summer monsoon weakened significantly, the rain bands moved southwards, and NC was relatively dry (Gong & Ho, 2002;Zhai et al, 2005).…”

Late Holocene Orbital Forcing and Solar Activity on the Kuroshio Current of Subtropical North Pacific at Different Timescales

“…Within the age uncertainty estimates, our IMF6+7 + 8 record of Core CF1 is broadly consistent with the abovementioned proxy evidence and suggests a slow-down of the KC during the period of 4.6-2.0 ka, followed by quickly enhanced KC and attaining the highest level at approximately 0.5 ka (Figure 6A). Additionally, climate records from the Taiwan Island (Selvaraj et al, 2007;Ding et al, 2020), SST of Core ZY2 (Wang et al, 2011). (C) ESNO events per 100-years (Moy et al, 2002).…”