Recent ecological responses to climate variability and human impacts in the Nianbaoyeze Mountains (eastern Tibetan Plateau) inferred from pollen, diatom and tree-ring data

2013 ◽  
Vol 51 (2) ◽  
pp. 287-302 ◽  
Author(s):  
Juliane Wischnewski ◽  
Ulrike Herzschuh ◽  
Kathleen M. Rühland ◽  
Achim Bräuning ◽  
Steffen Mischke ◽  
...  
2016 ◽  
Author(s):  
Xiaoxia Li ◽  
Eryuan Liang ◽  
Jozica Gricar ◽  
Sergio Rossi ◽  
Katarina Cufar ◽  
...  

ABSTRACTPhysiological and ecological mechanisms that define treelines are still debated. It is suggested that the absence of trees above the treeline is caused by the low temperature that limits growth. Thus, we raise the hypothesis that there is a critical minimum temperature (CTmin) preventing xylogenesis at treeline. We tested this hypothesis by examining weekly xylogenesis across three and four growing seasons in two natural Smith fir (Abies georgei var. smithii) treeline sites on the south-eastern Tibetan Plateau. Despite differences in the timing of cell differentiation among years, minimum air temperature was the dominant climatic variable associated with xylem growth; the critical minimum temperature (CTmin) for the onset and end of xylogenesis occurred at 0.7±0.4 °C. A process-based-modeled chronology of tree-ring formation using this CTmin was consistent with actual tree-ring data. This extremely low CTmin permits Smith fir growing at treeline to complete annual xylem production and maturation and provides both support and a mechanism for treeline formation.


2007 ◽  
Vol 3 (1) ◽  
pp. 119-128 ◽  
Author(s):  
O. Solomina ◽  
G. Wiles ◽  
T. Shiraiwa ◽  
R. D'Arrigo

Abstract. Tree ring, ice core and glacial geologic histories for the past several centuries offer an opportunity to characterize climate variability and to identify the key climate parameters forcing glacier expansion in Kamchatka over the past 400 years. A newly developed larch ring-width chronology (AD 1632–2004) is presented that is sensitive to past summer temperature variability. Individual low growth years in the larch record are associated with several known and proposed volcanic events from the Northern Hemisphere. The comparison of ring width minima and those of Melt Feature Index of Ushkovsky ice core helps confirm a 1–3 year dating accuracy~for this ice core series over the late 18th to 20th centuries. Decadal variations of low summer temperatures (tree-ring record) and high annual precipitation (ice core record) are broadly consistent with intervals of positive mass balances measured and estimated at several glaciers in 20th century, and with moraine building. According to the tree-ring data the 1860s–1880s were the longest coldest interval in the last 350 years. The latest part of this period (1880s) coincided with the positive anomaly in accumulation. This coincidence led to a positive mass balance, which is most likely responsible for glacier advances and moraine deposition of the end of 19th-early 20th centuries. As well as in some other high latitude regions (Spitsbergen, Polar Urals, Franz Jozef Land etc.) in Kamchatka these advances marked the last millennium glacial maximum. In full agreement with subsequent summer warming trend, inferred both from instrumental and tree ring data, glacier advances since 1880s have been less extensive. The late 18th century glacier expansion coincides with the inferred summer temperature decrease recorded by the ring width chronology. However, both the advance and the summer temperature decrease were less prominent that in the end of 19th century. Comparisons of the glacier history in Kamchatka with records from Alaska and the Canadian Rockies suggests broadly consistent intervals of glacier expansion and inferred summer cooling during solar irradiance minima.


2013 ◽  
Vol 9 (6) ◽  
pp. 2451-2458 ◽  
Author(s):  
J. Duan ◽  
L. Wang ◽  
L. Li ◽  
Y. Sun

Abstract. A large number of glaciers in the Tibetan Plateau (TP) have experienced wastage in recent decades. And the wastage is different from region to region, even from glacier to glacier. A better understanding of long-term glacier variations and their linkage with climate variability requires extending the presently observed records. Here we present the first tree-ring-based glacier mass balance (MB) reconstruction in the TP, performed at the Hailuogou Glacier in southeastern TP during 1868–2007. The reconstructed MB is characterized mainly by ablation over the past 140 yr, and typical melting periods occurred in 1910s–1920s, 1930s–1960s, 1970s–1980s, and the last 20 yr. After the 1900s, only a few short periods (i.e., 1920s–1930s, the 1960s and the late 1980s) were characterized by accumulation. These variations can be validated by the terminus retreat velocity of Hailuogou Glacier and the ice-core accumulation rate in Guliya and respond well to regional and Northern Hemisphere temperature anomaly. In addition, the reconstructed MB is significantly and negatively correlated with August–September all-India monsoon rainfall (AIR) (r1871-2008 = −0.342, p < 0.0001). These results suggest that temperature variability is the dominant factor for the long-term MB variation at the Hailuogou Glacier. Indian summer monsoon precipitation does not affect the MB variation, yet the significant negative correlation between the MB and the AIR implies the positive effect of summer heating of the TP on Indian summer monsoon precipitation.


Tellus B ◽  
2017 ◽  
Vol 69 (1) ◽  
pp. 1391663 ◽  
Author(s):  
Chenxi Xu ◽  
Xuemei Shao ◽  
Wenling An ◽  
Takeshi Nakatsuka ◽  
Yong Zhang ◽  
...  

2003 ◽  
Vol 30 (14) ◽  
Author(s):  
Qi-Bin Zhang ◽  
Guodong Cheng ◽  
Tandong Yao ◽  
Xingcheng Kang ◽  
Jianguo Huang

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 738
Author(s):  
Jianping Duan ◽  
Peili Wu ◽  
Zhuguo Ma

Volcanic eruptions are a major factor influencing global climate variability, usually with a cooling effect. The magnitudes of post-volcanic cooling from historical eruptions estimated by tree-ring reconstructions differ considerably with the current climate model simulations. It remains controversial on what is behind such a discrepancy. This study investigates the role of internal climate variability (i.e., El Niño/Southern Oscillation (ENSO) warm phase) with a regional focus on the Tibetan Plateau (TP), using tree-ring density records and long historical climate simulations from the fifth Coupled Model Intercomparsion Project (CMIP5). We found that El Niño plays an important role behind the inconsistencies between model simulations and reconstructions. Without associated El Niño events, model simulations agree well with tree-ring records. Divergence appears when large tropical eruptions are followed by an El Niño event. Model simulations, on average, tend to overestimate post-volcanic cooling during those periods as the occurrence of El Niño is random as part of internal climate variability.


Sign in / Sign up

Export Citation Format

Share Document