TY  - JOUR
A1  - Cao, Xianyong
A1  - Tian, Fang
A1  - Telford, Richard J.
A1  - Ni, Jian
A1  - Xu, Qinghai
A1  - Chen, Fahu
A1  - Liu, Xingqi
A1  - Stebich, Martina
A1  - Zhao, Yan
A1  - Herzschuh, Ulrike
T1  - Impacts of the spatial extent of pollen-climate calibration-set on the absolute values, range and trends of reconstructed Holocene precipitation
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Pollen-based quantitative reconstructions of past climate variables is a standard palaeoclimatic approach. Despite knowing that the spatial extent of the calibration-set affects the reconstruction result, guidance is lacking as to how to determine a suitable spatial extent of the pollen-climate calibration-set. In this study, past mean annual precipitation (P-ann) during the Holocene (since 11.5 cal ka BP) is reconstructed repeatedly for pollen records from Qinghai Lake (36.7 degrees N, 100.5 degrees E; north-east Tibetan Plateau), Gonghai Lake (38.9 degrees N, 112.2 degrees E; north China) and Sihailongwan Lake (42.3 degrees N, 126.6 degrees E; north-east China) using calibration-sets of varying spatial extents extracted from the modern pollen dataset of China and Mongolia (2559 sampling sites and 168 pollen taxa in total). Results indicate that the spatial extent of the calibration-set has a strong impact on model performance, analogue quality and reconstruction diagnostics (absolute value, range, trend, optimum). Generally, these effects are stronger with the modern analogue technique (MAT) than with weighted averaging partial least squares (WA-PLS). With respect to fossil spectra from northern China, the spatial extent of calibration-sets should be restricted to radii between ca. 1000 and 1500 km because small-scale calibration-sets (<800 km radius) will likely fail to include enough spatial variation in the modern pollen assemblages to reflect the temporal range shifts during the Holocene, while too broad a scale calibration-set (>1500 km radius) will include taxa with very different pollen-climate relationships. (C) 2017 Elsevier Ltd. All rights reserved.
KW  - Analogue quality
KW  - Statistical significance
KW  - Cross-validation
KW  - Holocene
KW  - Climate reconstruction
KW  - WA-PLS
KW  - MAT
Y1  - 2017
U6  - https://doi.org/10.1016/j.quascirev.2017.10.030
SN  - 0277-3791
VL  - 178
SP  - 37
EP  - 53
PB  - Elsevier
CY  - Oxford
ER  -