中文摘要：

随着气候场重建数据在揭示气候动力机制以及与数值模式模拟相结合等方面的应用,它在气候变化研究领域中的实用性和重要性已得到广泛认可.因此,关于空间格局重建方法的研究也就显得尤为重要.本文提出了一种新的气候场重建方法,即模态逼近的经验正交函数分解方法.该方法利用代用资料与器测资料不同空间模态之间的协调性,采用模态逐次逼近,从而实现对过去无器测资料覆盖的气候场的重建.基于该方法,本文利用549个树轮序列重建了北半球（22.5°N以北）公元1250年以来的地表气温空间场.为验证该方法的有效性,设计了多组验证试验,结果均表明该重建方法能够较好的再现器测数据的年代际尺度变率特征.最终重建结果表明,与已有研究结果相比,该方法重建出的北半球小冰期（1400～1700年）平均气候状态的空间格局特征与基于多组气候模式集合平均在该时段的模拟结果更为接近.另外,为体现重建结果对外强迫的响应特征,本文比较了在不同强度（强、中等、弱）典型火山年的空间格局差异,发现高纬度地区对火山外强迫相比于中低纬地区更加敏感,这与已有的基于数值模式模拟研究的结论基本一致.综合以上讨论,证明了该方法在气候场重建方面的有效性和应用潜力.

英文摘要：

As the climate field reconstruction （CFR） data have been used for important dynamical insights and its utility and significance is widely recognized, more research on CFR methodologies is therefore urgently needed. In this paper, a new technique for climate field reconstruction was developed, i.e. Mode Approached Empirical Orthogonal Function （MA-EOF） method. This method allowed appropriate modes being preserved at different iteration steps, which utilized the intrinsic connections of EOFs, so that the reconstructed data over earlier times was approaching to the ＂true state＂ step by step. We collected the tree-ring data mainly from the International Tree-Ring Data Bank （ITRDB） and PAGES 2k network, and screened them by the correlation coefficients with the observed annual temperature in their respective neighboring grids （exceeding the threshold values at 95% significance level）. Finally, 549 temperature sensitivetree-ring chronologies were screened out, including 269 records from ITRDB, 267 from PAGES 2k network, 7 from China Meteorological Science Data Sharing Service Network and 6 from some published literatures related on regional temperature signal. The screened chronologies were divided into 17 groups according to their covered period and the starting year of the groups were set every 50 years from 1800A.D. to 1000A.D. The validation results verified the reliability of the reconstructions based on 1 -12 group, and demonstrated the efficiency of the MA-EOF method particularly in reconstructing decadal variability of the instrumental data. Therefore, the gridded reconstructions of the first twelve groups were averaged as spatial pattern of the extratropical Northern Hemisphere 1850A.D. based on the MA-EOF method. the final gridded reconstruction, i.e. we reconstructed the （22.5°- 90°N） temperature during the period 1250 -1850A.D. based on the MA-EOF method. In order to highlight the performance of different methods using for large-scale temperature spatial pattern reconstruction,