A method to separate temperature and precipitation signals encoded in tree-ring widths for the western Tien Shan Mountains, northwest China

Abstract

Separating temperature and precipitation signals encoded in tree rings is a complicated issue. Here, we present a separation method by combining two tree-ring width chronologies of Schrenk's spruce (Picea schrenkiana) from the upper and lower timberlines in the western Tien Shan Mountains, northwest China. Correlation analyses show that both chronologies correlate positively with precipitation. However, temperature correlates positively with the chronology from the upper timberline, while negatively with the chronology from the lower timberline. This suggests that the two chronologies contain similar precipitation information but opposite temperature signals. In light of this, we calculated the average and difference of the two chronologies, and found that each of them has a much stronger correlation with precipitation or temperature alone. Finally, we reconstructed local precipitation and temperature variations over the past 201 years by using the average and difference of the two chronologies. The two reconstructions do not have a significant correlation, but they have significant positive and negative relationships on the high-and low-frequency band, respectively.

Climate–growth relationships of Schrenk spruce (Picea schrenkiana) along an altitudinal gradient in the western Tianshan mountains, northwest China

“…The Tianshan Mountains are considered as an area sensitive to global climate change (Sang et al 2007). There are a growing number of dendrochronological studies being conducted in this region (e.g., Yuan and Li 1999;Yuan et al 2000;Yuan et al 2001;Zhu et al 2004;Wang et al 2005;Li et al 2006;Chen et al 2010;Chen et al 2013;Wu et al 2013b;Liu et al 2015;Wu et al 2015). The Schrenk spruce (Picea schrenkiana) forests are distributed across a wide altitudinal range in the Tianshan Mountains, and play a vital role in local ecosystems.…”

A 333-year record of the mean minimum temperature reconstruction in the Western Tianshan Mountains, China

“…Streamflow reconstructions have focused mainly on the central and western regions of the Tianshan Mountains, such as the Manas River, Jinghe River, Urumqi River and Guxiang River (Yuan et al, 2007;Chen and Yuan, 2016;Zhang et al, 2016). Precipitation reconstructions have been distributed throughout the Tianshan Mountains, especially in the western Tianshan Mountains (Yuan et al, 2001;Shang et al, 2010;Zhang et al, 2013a;Liu et al, 2015;Zhang et al, 2015;Chen et al, 2017). Drought reconstructions have been concentrated in the central and eastern Tianshan Mountains based on the Palmer drought severity index (PDSI), but fewer drought reconstructions have been based on the better Standardized Precipitation Evapotranspiration Index (SPEI) (containing precipitation, temperature, relative humidity, solar radiation, water vapour pressure, and wind speed) (Chen et al, 2013(Chen et al, , 2016Xu et al, 2015a;Xu et al, 2015b;Jiang et al, 2017).…”