ADVANCES IN CLIMATE CHANGE RESEARCH 2(1): 38–42, 2011 www.climatechange.cn DOI: 10.3724/SP.J.1248.2011.00038 ARTICLE
Test Calibration of the Paleoclimatic Proxy Data with Chinese Historical Records De’er Zhang National Climate Center, China Meteorological Administration, Beijing 100081, China
Abstract The calibration of paleoclimate proxies is one of the key problems in the study of paleoclimate at present. Historical documentary records of climate are suitable for calibration on dating and the climatic implication of the proxy data in a climatological sense. A test calibration on correcting the Delingha tree ring precipitation series using Chinese historical documentary records shows that among the 44 extreme dry cases in 1401–1950 AD, 42 cases (or 95.5%) are believable. Thus the long series of Delingha rings-denoted precipitation is highly reliable. Another test to validate the monsoon intensity proxy data based on the Zhanjiang Huguangyan sediments using historical records indicates that the years of Lake Maar Ti content series-designated winter monsoon intensities are entirely opposite to historical documentsdepicted years of harsh winters in 800–900 AD. As a result, serious doubt is raised about the climatic implication of this paleo-monsoon proxy series. Keywords: proxy data; calibration; paleoclimate; historical documentary records of climate Citation: Zhang, D., 2011: Test calibration of the paleoclimatic proxy data with Chinese historical records. Adv. Clim. Change Res., 2(1), doi: 10.3724/SP.J.1248.2011.00038.
1 Introduction
surements have been drastically increased, and many high-resolution proxies have been published one after another. But the inconsistency and even contradiction among them has become a disturbing issue in ongoing studies of paleoclimate. Historical documentary records of climate characterized by accurate and reliable recording of time (to year, even to month or day), and by the certainty of locations and understandable implication of climatic elements (temperature, rainfall, etc.) make it possible to compare them to the proxy data for calibration on dating and the implication of the proxy data in a climatological sense. Early encouraging attempts include a comparison of the curve of δ 18 O ratios of ice core of Dunde in the Qilianshan Mountains published in 1991 [Yao et al., 1991] with the 500-year winter temperature series of Shanghai derived from historical records and reported
Any proxy dataset obtained from natural sources (e.g., lake sediments, stalagmite, and tree rings) has to be compared with data obtained from other sources (including instrumental and historical documentary records), in order to confirm the correctness of interpreted climate implication involved in these proxy data, the precision of measured or induced data, and the accuracy in dating. This is an indispensable step in determining the usefulness of such scientific records. The author believes that the calibration of paleoclimate proxies is one of the key problems in the study of paleoclimate today. In recent years, rapid progress has been made in studies of paleoclimate, the approaches to obtain paleoclimate proxies have been expanded, data acquired from field samples and laboratory meaReceived: 17 December 2010 Corresponding author: De’er Zhang,
[email protected]
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De’er Zhang / Test Calibration of the Paleoclimatic Proxy Data with Chinese Historical Records
by Zhang [1980] (Fig.1), which showed their conformity on a 10-year scale [Zhang, 1995]. In addition, the comparison of the curve of dust depositing events in Chinese history [Zhang, 1983] published in 1982 with the later reported content of fine particles in ice cores in Western China [Yao et al., 1995] and with that in the Greenland Site-J ice core [Tegen and Rind, 2000](figure is omitted), indicated consistency between historical and natural records. These results provided us with confidence in the proxy data.
Figure 1
Comparison of δ 18 O series of Dunde ice cord
[Yao et al., 1991] and winter temperature series of Shanghai inferred from the Chinese ancient documents [Zhang, 1980] for the last 500 years (redrawn from [Zhang, 1995])
2 Calibration of dating with Chinese historical records Proxy data of rainfall derived from tree rings have a temporal resolution of a year, that can be employed to make comparison with historical record inferred dry/wet climate regimes. The inconsistency between them either provides clues for further investigation of the historical records or corrects the dating of tree ring series. More importantly, of course, the consistency in their intercomparison will provide convincing evidence for the accuracy of these scientific data. Test calibration was performed on the Delingha tree ring-denoted precipitation series in 1001–2000 AD using Chinese historical documentary records. This yearly rainfall series was constructed by use of interring width in well-replicated samples from 7 sites including Delingha and Wulan of Qinghai province and the reconstructed series is equivalent to the annual pre-
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cipitation in a general sense [Shao et al., 2004]. The series (1001–2000 AD) has an annual mean precipitation of 132 mm, and a standard deviation σ=34 mm. If the annual precipitation anomaly at 1.7σ (=75 mm) is set for the extreme dry year, then such years of R
