Pollen-Based Quantitative Reconstruction of Holocene Climate Changes in the Daihai Lake Area, Inner Mongolia, China

Abstract

Vegetation around the Daihai Lake, northern China, is very sensitive to climate changes. In this paper, pollen-based quantitative climate reconstructions using three methods [weighted averaging partial least squares method (WAPLS), modern analog technique (MAT), and pollen response surface method (PRS)] were conducted to obtain robust reconstructions of Holocene climate changes in the Daihai Lake area. The result obtained by the three methods all consistently show the annual precipitation to have been 50-100 mm lower in the early Holocene, 100-200 mm higher in the Mid-Holocene, and 50-100 mm lower again in the late Holocene than at present. The WAPLS and the MAT methods also show quasi-synchronous oscillations of the mean annual temperature (Ta); 18-28C lower in the Early Holocene and 18-38C higher in the MidHolocene than today. The time period from 6200 to 5100 cal yr BP was the wettest and the warmest interval, with an annual precipitation (Pa) greater than 550 mm and mean annual temperature Ta higher than 6.58C. Several cold and dry events can be identified to occur about 8200, 6000, and 4400 cal yr BP, with an annual precipitation less than 400 mm and a mean annual temperature colder than 4.58C, respectively. The mean temperature of the warmest month (Tw) as reconstructed using both WAPLS and MAT methods was relatively stable during the Holocene, fluctuating about 628C relative to the present level, but the PRS method suggests more varied Tw values in both amplitude and frequency. After 1500 cal yr BP, no consistent pattern can be observed from these three different analyses, probably because of the impact of intensified human disturbances on the natural vegetation. The fluctuations of annual precipitation (Pa) correspond to that observed in Dongge Cave in southern China. The differences might be linked to Indian monsoon and East Asia monsoon climates or caused by the different degree of dating precision, different temporal resolution, and different sensitive response of climate proxies to the climate variations.

Biome changes in Asia since the mid-Holocene – an analysis of different transient Earth system model simulations

“…The biome change in the forest-steppe transition zone is reflected by the record from Lake Daihai in Inner Mongolia (China; 40.5 • N, 112.5 • E; 1225 m a.s.l. ; Xu et al, 2010) that is in line with other records in north-central China , and references therein). To better compare the simulated biome distribution, these records were biomised in accordance with the BIOME4 biome classification.…”

“…Shown is also the present-day extent of the Asian summer monsoon region (light blue) based on the observed mean 2 mm/day summer isohyet (taken from GPCP data; Adler et al, 2003). Red numbers mark the location of the pollen sites: 1 is Lake Daihai (40.5 • N, 112.5 • E; Xu et al, 2010) and 2 is small lake on southern Taymyr Peninsula 72.4 • N, 102.29 • E; Klemm et al, 2016). tribution but also for the analysis of Holocene vegetation changes.…”

The MILLENNIA peat cohort model: predicting past, present and future soil carbon budgets and fluxes under changing climates in peatlands

“…However, such data are available for other regions across the globe at similar latitudes, mainly based on pollen records (e.g. Xu et al 2009). These data show rapid warming and increased precipitation around 10k years ago and subsequently some variability in mean climate parameters, with certain periods of significant change (e.g.…”

“…We used (1) a combination of 2 North American (NA) datasets (Gajewski et al 2004, Bunbury et al 2006), but adjusted the onset of major change to 10k years ago to reflect UK conditions; (2) a reconstruction based on Oak Ridge National Laboratory (ORNL) information (www.esd. ornl.gov/projects/qen/nercEUROPE.html) using records for China (Xu et al 2009) as an indication of the magnitude of changes; and (3) a constant present climate (4.75°C and 1922 mm) based on elevation-corrected MetOffice (gap free) records from 1931 to 2005 (Clark et al 2010, this Special). Crucially, such data include MAT and MAP, which can be used to derive AET using a simple equation (Turc 1954); although more sophisticated equations exist, the necessary input data are currently not available for the Holocene, although future projects might deliver much better Holocene climate reconstructions (e.g.…”

A chironomid-based record of temperature variability during the past 4000 years in northern China and its possible societal implications

“…During the past few decades, various studies have reconstructed temper-ature change on different timescales in northern China, using for example pollen (e.g. Wen et al, 2010;Xu et al, 2010), glycerol dialkyl glycerol tetraethers (GDGTs; e.g. Gao et al, 2012;Jia et al, 2013;Peterse et al, 2014), stalagmites (Tan et al, 2003) and historical archives (Ge et al, 2003).…”