多年冻土区土壤湿度的动态变化及影响
陈珊珊, 臧淑英, 孙 丽

(哈尔滨师范大学 寒区地理环境监测与空间信息服务黑龙江省重点实验室, 哈尔滨 150025)

土壤湿度; 时空变化; 植被; 东北多年冻土区

Dynamic Variation of Soil Moisture and Impact in Permafrost Regions in Northeast China
CHEN Shanshan, ZANG Shuying, SUN Li

(Heilongjiang Province Key Laboratory of Geographical Environment Monitoring and Spatial Information Service in Cold Regions, Harbin Normal University, Harbin 150025, China)

soil moisture; spatiotemporal variation; vegetation; permafrost region in northeastern China

备注

气候变暖导致高纬度多年冻土退化,引起多年冻土区冻融过程和土壤水热过程发生变化,土壤湿度变化对气候和生态系统产生重要影响。运用ERA-Interim再分析的土壤湿度数据,结合气象数据,采用数理统计方法,分析了1979—2017年东北多年冻土区土壤湿度的年际、季节和空间变化,土壤湿度变化的影响因子及土壤湿度变化所带来的影响。研究表明:年际变化上1979—2017年,东北多年冻土区7 cm和28 cm深度年均土壤湿度呈下降趋势,并且年平均土壤湿度在2008年达到最低; 在季节变化上,不同深度土壤湿度在夏秋季节会达到一年中的最大值,7 cm和28 cm深度处土壤湿度呈现两个峰值(4月份、8月份),土壤湿度最大值出现在8月份; 在空间变化上,东北多年冻土区中部土壤湿度在1979—2017年变化最大,且为土壤湿度下降明显区。在气候变暖和降水持续减少的背景下,土壤水分可能成为影响东北多年冻土区植被生长的主要因子,使东北多年冻土区植被生态系统发生变化,分析东北多年冻土区土壤湿度的时空变化对进一步理解该区生态系统变化和多年冻土碳反馈效应具有重要意义。

Climate warming leads to permafrost degradation in the high latitudes, causing changes of freeze-thaw processes of active layer and soil hydrothermal processes in permafrost regions. Soil moisture is a key variable in the climate system. Its variation would cause impact on the climate system and vegetation ecosystems. Using mathematical statistics method and the EAR-Interim, we reanalyzed soil moisture data set to examine the spatial-temporal characteristics of soil moisture. On the basis, meteorological data were used to explain the reasons of soil moisture change and its changes would lead to the influence on the environment and ecology in the permafrost regions in Northeastern China. The results show that: from 1979 to 2017, the mean annual soil moisture in the permafrost regions of northeast China had been decreasing in 7 cm, and 28 cm depths, and the annual soil moisture was the lowest in 2008; in terms of seasonal changes, soil moisture had reached the maximum in the summer and autumn; the soil moisture in 7 cm and 28 cm depths had two peaks, namely, the peaks occurred in April and August, the maximum soil moisture occurred in August; in terms of spatial variation, the soil moisture had changed significantly in the central zone of the permafrost region in northeast China, and soil moisture had been decreasing in the entire permafrost region. Under the background of global climate warming and precipitation reduction, soil moisture may become the main factor affecting vegetation growth and other ecosystem processes in the permafrost regions of northeast China. Research for the spatial and temporal changes of soil moisture is of great significance to further understand the ecosystem changes and permafrost carbon feedback effects in the permafrost region in northeastern China.