Moisture variation inferred from tree rings in north central China and its links with the remote oceans

Abstract

In this study we presented a composite standard chronology, spanning 1635–2018 to reconstruct May–July moisture variation in north central China. Our reconstruction revealed four severe dry epochs and five pronounced wet epochs. Additionally, spatial correlation analysis of our reconstruction with the actual self-calibrating Palmer drought severity index showed that our reconstruction was representative of large-scale May–July moisture changes. Both the severe dry and pronounced wet epochs showed one-to-one correspondence with other reconstructions nearby during their common periods, which demonstrated the reliability of our reconstruction backwards in time. Spectral analysis showed that significant spectral peaks were found at 2.1–3.8 years, which fell within the overall bandwidth of the El Niño-Southern Oscillations (ENSO). The spatial correlation patterns between our reconstruction and sea surface temperature (SST) in the equatorial eastern Pacific further confirmed the link between regional moisture and ENSO, with warm-phase ENSO resulting in low moisture and vice-versa. However, this link was time-dependent during the past four centuries, and was modulated by different phases of SST in the tropical Indian Ocean. Additionally, significant peaks at 24.9–46.5 years and spatial correlation patterns indicated that the Pacific Decadal Oscillation and the North Atlantic Oscillation may be the possible forcing factors of regional moisture at lower frequencies.

Growth Response of Thai Pine (Pinus latteri) to Climate Drivers in Tak Province of Northwestern Thailand

“…Previous studies showed that a lower temperature and higher rainfall are associated with El Niño events and vice versa for La Niña events [17][18][19][20]. Dendrochronological analyses (i.e., tree ring studies) serve as important tools that can be used to investigate the influence of climatic forces on tree growth [27][28][29][30][31][32][33] and are widely used for climatic reconstructions in many regions [34][35][36][37][38][39], particularly Asia [40][41][42][43][44][45][46]. The understanding of Thai tree-growth dynamics has been limited in space and time due to the scarcity of long-term tree-growth data (e.g., [47]).…”

Understanding the Natural Variability of Still Water Levels in the San Francisco Bay Over the Past 500 yr: Implications for Future Coastal Flood Risk

“…In this study, we explore multi‐timescale natural variability in coastal flooding through innovative uses of the paleorecord to reconstruct plausible sequences of water levels and the likelihood of coastal flood events. Past studies have used a combination of tree rings and marine and nearshore paleo proxies, including geochemical proxies, to reconstruct total seasonal precipitation (Chen et al., 2015; Neukom et al., 2014; Williams et al., 2021), extreme precipitation (Borkotoky et al., 2021; Steinschneider et al., 2016, 2018), regional moisture transport (Mukhopadhyay et al., 2018; Zheng et al., 2021), drought (Baek et al., 2019; McCabe et al., 2008; Woodhouse et al., 2010), global surface temperature (Osman et al., 2021), terrestrial climate (Krapp et al., 2021), SSTs (Emile‐Geay et al., 2013, 2015; Freund et al., 2019), and sea surface salinity (Nurhati et al., 2011). These studies rely on robust relationships between environmental signals embedded within networks of paleo‐proxies and large‐scale oceanic and atmospheric conditions that determine the likelihood of those environmental responses.…”