气候变化领域集成服务门户(CCPortal): A new multivariable benchmark for Last Glacial Maximum climate simulations

CCPortal

DOI	10.5194/cp-16-699-2020
	A new multivariable benchmark for Last Glacial Maximum climate simulations
	Cleator S.F.; Harrison S.P.; Nichols N.K.; Colin Prentice I.; Roulstone I.
发表日期	2020
ISSN	18149324
起始页码	699
结束页码	712
卷号	16 期号:2
英文摘要	We present a new global reconstruction of seasonal climates at the Last Glacial Maximum (LGM, 21 000 years BP) made using 3-D variational data assimilation with pollen-based site reconstructions of six climate variables and the ensemble average of the PMIP3 - CMIP5 simulations as a prior (initial estimate of LGM climate). We assume that the correlation matrix of the uncertainties in the prior is both spatially and temporally Gaussian, in order to produce a climate reconstruction that is smoothed both from month to month and from grid cell to grid cell. The pollen-based reconstructions include mean annual temperature (MAT), mean temperature of the coldest month (MTCO), mean temperature of the warmest month (MTWA), growing season warmth as measured by growing degree days above a baseline of 5 °C (GDD5), mean annual precipitation (MAP), and a moisture index (MI), which is the ratio of MAP to mean annual potential evapotranspiration. Different variables are reconstructed at different sites, but our approach both preserves seasonal relationships and allows a more complete set of seasonal climate variables to be derived at each location. We further account for the ecophysiological effects of low atmospheric carbon dioxide concentration on vegetation in making reconstructions of MAP and MI. This adjustment results in the reconstruction of wetter climates than might otherwise be inferred from the vegetation composition. Finally, by comparing the uncertainty contribution to the final reconstruction, we provide confidence intervals on these reconstructions and delimit geographical regions for which the palaeodata provide no information to constrain the climate reconstructions. The new reconstructions will provide a benchmark created using clear and defined mathematical procedures that can be used for evaluation of the PMIP4-CMIP6 entry-card LGM simulations and are available at https://doi.org/10.17864/1947.244 (Cleator et al., 2020b). © 2020 Author(s).
语种	英语
scopus关键词	carbon dioxide; CMIP; data assimilation; growing season; Last Glacial Maximum; reconstruction; simulation
来源期刊	Climate of the Past
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146723
作者单位	Department of Mathematics, University of Surrey, Guildford, GU2 7XH, United Kingdom; School of Archaeology, Geography and Environmental Science, University of Reading, Whiteknights, Reading, RG6 6AH, United Kingdom; Department of Mathematics and Statistics, University of Reading, Whiteknights, Reading, RG6 6AX, United Kingdom; AXA Chair in Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, United Kingdom
推荐引用方式 GB/T 7714	Cleator S.F.,Harrison S.P.,Nichols N.K.,et al. A new multivariable benchmark for Last Glacial Maximum climate simulations[J],2020,16(2).
APA	Cleator S.F.,Harrison S.P.,Nichols N.K.,Colin Prentice I.,&Roulstone I..(2020).A new multivariable benchmark for Last Glacial Maximum climate simulations.Climate of the Past,16(2).
MLA	Cleator S.F.,et al."A new multivariable benchmark for Last Glacial Maximum climate simulations".Climate of the Past 16.2(2020).