中文摘要：

近年来，众多研究报道了华北平原土壤有机碳具有明确地显著增加的趋势，表现出“碳汇”的效应，但是，华北平原土壤有机碳对气候变化的响应尚未明确。基于已有研究结果的基础上，利用河北平原区多目标区域地球化学调查的20029个土壤分析数据和河北省各气象站多年年均温度和年降水量资料，采用多元线性回归模型的方法，分析探讨了土壤有机碳密度及其变化量在不同年均温度和年降水量带下对气候变化的响应。结果表明，研究区年均温度变化为0.29℃/10a，年降水变化为-25.99 mm/10a。河北平原区表层土壤有机碳密度为0.18-18.72 kg/m2，平均为（2.19±0.78） kg/m2，其空间分布呈由西向东递减的趋势，土壤有机碳储量的变化量为39.17 Mt。相关分析结果表明，温度是河北平原区土壤有机碳密度及其变化量的主控气候因素，但是，其受到降水量的制约。但研究区土壤有机碳及其变化与年均温度、年降水量并不服从简单的依变关系，还存在其他因素的影响，而农业活动很可能就是气候因素之外影响土壤有机碳的重要因素。研究表明，充分考虑到研究区的年均温度和年降水量分带等因素，可以有效地分析大尺度区域范围内的气候因素对土壤有机碳的影响。

英文摘要：

Recently, a signiifcant increase in soil organic carbon storage in the North China Plain has been reported as carbon sinks by a number of studies, while the corresponding relationship of soil organic carbon with climate change remains uncertain. Based on the previous studies, a total of 20 029 surface soil samples of national multipurpose regional geochemical survey and the data of annual average temperature and annual precipitation of the related weather stations were used to analyze the relationships between topsoil organic carbon density and annual average temperature and annual precipitation by applying the multiple linear regression in Hebei Plains. The different zones characterised by the temperature and precipitation were also taken into consideration in the present study. The results show that the changes of annual average temperature and annual precipitation are 0.29℃per 10 years and-25.99 mm per 10 years, respectively. The average soil organic carbon density in the study area is （2.19 ± 0.78） kg/m2, with a range of 0.18-18.72 kg/m2, decreasing from West to East spatially. The change of soil organic carbon storage is 39.17 Mt. According to the linear regression modeling with climatic factors as predictors, the soil organic carbon density in the study area is mainly＆amp;nbsp;controlled by the change of temperature, and is restricted by precipitation as well. However, the soil organic carbon and its change depend on not only the annual average temperature and annual precipitation, but also other factors, such as agricultural activities, which inlfuence the soil organic carbon in the study area. Our results indicate that the inlfuence of climatic factors on soil organic carbon at large scales can be effectively illustrated by taking full account of the annual average temperature and annual precipitation zones.