气候变化领域集成服务门户(CCPortal): Seasonal reconstructions coupling ice core data and an isotope-enabled climate model - Methodological implications of seasonality; climate modes and selection of proxy data

CCPortal

DOI	10.5194/cp-16-1737-2020
	Seasonal reconstructions coupling ice core data and an isotope-enabled climate model - Methodological implications of seasonality; climate modes and selection of proxy data
	Sjolte J.; Adolphi F.; Vinther B.M.; Muscheler R.; Sturm C.; Werner M.; Lohmann G.
发表日期	2020
ISSN	18149324
起始页码	1737
结束页码	1758
卷号	16 期号:5
英文摘要	The research area of climate field reconstructions has developed strongly during the past 20 years, motivated by the need to understand the complex dynamics of the earth system in a changing climate. Climate field reconstructions aim to build a consistent gridded climate reconstruction of different variables, often from a range of climate proxies, using either statistical tools or a climate model to fill the gaps between the locations of the proxy data. Commonly, large-scale climate field reconstructions covering more than 500 years are of annual resolution. In this method study, we investigate the potential of seasonally resolved climate field reconstructions based on oxygen isotope records from Greenland ice cores and an isotope-enabled climate model. Our analogue-type method matches modeled isotope patterns in Greenland precipitation to the patterns of ice core data from up to 14 ice core sites. In a second step, the climate variables of the best-matching model years are extracted, with the mean of the best-matching years comprising the reconstruction. We test a range of climate reconstructions, varying the definition of the seasons and the number of ice cores used. Our findings show that the optimal definition of the seasons depends on the variability in the target season. For winter, the vigorous variability is best captured when defining the season as December-February due to the dominance of large-scale patterns. For summer, which has weaker variability, albeit more persistent in time, the variability is better captured using a longer season of May-October. Motivated by the scarcity of seasonal data, we also test the use of annual data where the year is divided during summer, that is, not following the calendar year. This means that the winter variability is not split and that the annual data then can be used to reconstruct the winter variability. In particularly when reconstructing the sea level pressure and the corresponding main modes of variability, it is important to take seasonality into account, because of changes in the spatial patterns of the modes throughout the year. Targeting the annual mean sea level pressure for the reconstruction lowers the skill simply due to the seasonal geographical shift of the circulation modes. Our reconstructions based on ice core data also show skill for the North Atlantic sea surface temperatures, in particularly during winter for latitudes higher than 50 N. In addition, the main modes of the sea surface temperature variability are qualitatively captured by the reconstructions. When testing the skill of the reconstructions using 19 ice cores compared to the ones using eight ice cores, we do not find a clear advantage of using a larger data set. This could be due to a more even spatial distribution of the eight ice cores. However, including European tree-ring data to further constrain the summer temperature reconstruction clearly improves the skill for this season, which otherwise is more difficult to capture than the winter season. © Author(s) 2020.
语种	英语
scopus关键词	climate modeling; ice core; numerical model; proxy climate record; reconstruction; seasonal variation; seasonality
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/146671
作者单位	Department of Geology - Quaternary Science, Lund University, Sölvegatan 12, Lund, 22362, Sweden; Swedish Meteorological and Hydrological Institute, 60176 Norrköping, Sweden; Climate and Environmental Physics and Oeschger Centre for Climate Change Research, Physics Institute, University of Bern, Sidlerstrasse 5, Bern, 3012, Switzerland; Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark; Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Sciences, Bussestr 24, Bremerhaven, 27515, Germany
推荐引用方式 GB/T 7714	Sjolte J.,Adolphi F.,Vinther B.M.,et al. Seasonal reconstructions coupling ice core data and an isotope-enabled climate model - Methodological implications of seasonality; climate modes and selection of proxy data[J],2020,16(5).
APA	Sjolte J..,Adolphi F..,Vinther B.M..,Muscheler R..,Sturm C..,...&Lohmann G..(2020).Seasonal reconstructions coupling ice core data and an isotope-enabled climate model - Methodological implications of seasonality; climate modes and selection of proxy data.Climate of the Past,16(5).
MLA	Sjolte J.,et al."Seasonal reconstructions coupling ice core data and an isotope-enabled climate model - Methodological implications of seasonality; climate modes and selection of proxy data".Climate of the Past 16.5(2020).