Unprecedented recent late-summer warm extremes recorded in tree-ring density on the Tibetan Plateau

Abstract

Tree-ring records have shown a significant upward trend of late summer temperatures over the Tibetan Plateau (TP) in recent decades. More detailed instrumental observations over the TP have also shown an increase in warm extremes, especially in the high-altitude area. It is not clear whether the recent increase in occurrence of warm extremes on the TP reflects an amplification of recent temperature fluctuations or it relates to the long-term climate trend. This study aims to address the above question by analyzing long-term late summer (August-September) temperature extremes over the TP using temperature reconstructions derived from tree-ring maximum latewood density. Our results show that the recent frequency of late summer warm extremes was unprecedented over the past four centuries, while the occurrence of cold extremes in the instrumental interval was minimal. However, after the removal of long-term trend, the frequencies of both warm and cold extremes in the instrumental period are actually smaller than the pre-instrumental period, indicating a decreased variability of late summer temperatures. Thus, we conclude that the recent observed increase in warm extremes is related to the long-term warming trend, rather than an amplification of temperature variability. This finding implies that the persistent warming on the TP in the future might trigger much more frequent warm extremes with potential ecological and environmental effects.

The Climate-Growth Relationship between Picea smithiana (Wall.) Boiss. and Abies pindrow (Royle ex D.Don) Royle along the Latitudinal Gradient in Northern Pakistan

“…The Velmex measurement system was used to measure the width of tree-rings with a minor count (precision) of up to 0.001 mm (Velmex, Bloomfield, NY, USA). The COFFECHA program was used to check the quality of tree-ring measurement and the exact date of ring formation for each core, termed cross-dating [76,77]. Ring samples of the same tree species collected from different sites can be cross-dated by matching annual rings between the different cores.…”

Spatiotemporal Trends of Extreme Temperature Events Along the Qinghai‐Tibet Plateau Transportation Corridor From 1981 to 2019 Based on Estimated Near‐Surface Air Temperature

“…As a significant traffic corridor in China, the Qinghai‐Tibet Plateau Transportation Corridor (QTPTC) faces tremendous threats from multiple potential disasters, such as landslides (Bian et al., 2021), extreme temperatures, and extreme rainfalls (J. Zhang et al., 2021). Nearly all warming indicators on the Tibetan Plateau (where the corridor is located) exhibit greater intensity and frequency than those in the eastern region or indeed the whole of China (Yin et al., 2019), and this persistent warming phenomenon might trigger more frequent extreme events in the future (J. Duan et al., 2020). Studying the extreme temperature events trends along the QTPTC offers crucial guidance to policymakers on regional safety, albeit research in this field remains limited.…”

“…Nearly all warming indicators on the Tibetan Plateau (where the corridor is located) exhibit greater intensity and frequency than those in the eastern region or indeed the whole of China (Yin et al, 2019), and this persistent warming phenomenon might trigger more frequent extreme events in the future (J. Duan et al, 2020). Studying the extreme temperature events trends along the QTPTC offers crucial guidance to policymakers on regional safety, albeit research in this field remains limited.…”