Tree‐ring‐based precipitation reconstruction in the source region of Weihe River, northwest China since AD 1810

Abstract

A tree‐ring width chronology of Picea purpurea Mast from Mt. Shouyang in the source region of Weihe River (SWR), northwest China, was developed in this study. Correlation analysis showed that the precipitation from previous August to current July was the limiting climate factor of tree growth. Using a reliable and stable linear regression model, which explained 42.6% of the variance of the actual precipitation during the calibration period from 1958 to 2014, a 205‐year long precipitation series was reconstructed for the SWR. The dry years in the reconstruction were well supported by historical documents, and famous historical droughts were also recorded in the dry periods of a low‐frequency scale of the reconstructed precipitation. As demonstrated by the spatial correlation patterns, the reconstructed series compared well with other hydroclimate records for northwest China, indicating that it could represent large‐scale hydroclimate changes. The 2–8‐year interannual cycles and the interdecadal quasiperiods of 15.9 years and 18.6 years revealed that the precipitation in this region was probably affected by the El Niño‐Southern Oscillation and North Atlantic Oscillation. The dry/wet years corresponded well with the El Niño/La Niña events and the SWR commonly experienced droughts during the low periods of North Atlantic Oscillation.

Anthropogenic Aerosols Cause Recent Pronounced Weakening of Asian Summer Monsoon Relative to Last Four Centuries

“…Shoulu, Mt. Shouyang, Zunisi, and Tulugou (two chronologies at the site) were previously published data (Liu, Lei, Sun, Song, & Li, , Liu, Lei, Sun, Song, & Sun, ; Song et al, ; Sun et al, ). Chronologies from Mt.…”

“…Cores from a minimum of 20 individual trees were collected using increment borers at each site. Each chorology has a strong local precipitation signal (Fang et al, ; Liu et al, , Liu, Lei, Sun, Song, & Li, , Liu, Lei, Sun, Song, & Sun, , Liu, Sun, et al, ; Ma et al, ; Song & Liu, ; Song et al, ; Sun et al, ), and the correlation coefficients among them are statistically significant (Table S2). LINTAB system was used to measure tree ring widths of each core with an accuracy up to 0.001 mm.…”

“…(c) Comparison of reconstructed (red line) by tree rings and the observed (black line) precipitation data of P JJ during 1952-2013 CE. Li, 2013Song et al, 2017;Sun et al, 2018). Chronologies from Mt.…”

Documentary data and the study of past droughts: a global state of the art

“…The term "drought" encompasses a complex phenomenon; it is used to express a prolonged period of negative deviation in water balance compared to the climatological norm in a given area (Wilhite and Pulwarty, 2018). Drought is a normal, recurrent feature of climate that occurs in virtually all climate zones (Svoboda and Fuchs, 2018). One of the related environmental phenomena associated with more frequent and severe drought can be desertification, which not only has an impact on the environment but may also have severe consequences for human society (e.g.…”

“…Drought may be defined in terms of several different characteristics and indices (e.g. Heim, 2000Heim, , 2002Keyantash and Dracup, 2002;Svoboda and Fuchs, 2018). SPI (Standardized Precipitation Index;McKee et al, 1993) is one of those frequently employed in examinations of meteorological drought.…”