A new climate scenario for assessing the climate change impacts on soil moisture over the Huang–Huai–Hai Plain region of China

摘要

To assess the impacts of temperature and precipitation changes on surface soil moisture (SSM) in the Huang–Huai–Hai Plain (3H) region of China, the approach of conditional nonlinear optimal perturbation related to parameters (CNOP-P) and the Common Land Model are employed. Based on the CNOP-P method and climate change projections derived from 22 global climate models from CMIP5 under a moderate emissions scenario (RCP4.5), a new climate change scenario that leads to the maximal change magnitudes of SSM is acquired, referred to as the CNOP-P type temperature or precipitation change scenario. Different from the hypothesized climate change scenario, the CNOP-P-type scenario considers the variation of the temperature or precipitation variability. Under the CNOP-P-type temperature change, the SSM changes in the last year of the study period mainly fluctuate in the range from ?0.014 to?+0.012?m~(3)?m~(?3) (?5.0% to?+10.0%), and from?+0.005 to?+0.018?m~(3)?m~(?3) (+1.5% to?+9.6%) under the CNOP-P-type precipitation change scenario. By analyzing the difference of the SSM changes between different types of climate change scenarios, it is found that this difference associated with SSM is obvious only when precipitation changes are considered. Besides, the greater difference mainly occurs in north of 35°N, where the semi-arid zone is mainly situated. It demonstrates that, in the semi-arid region, SSM is more sensitive to the precipitation variability. Compared with precipitation variability, temperature variability seems to play little role in the variations of SSM.摘要本文基于CNOP-P方法、CoLM模式以及22个CMIP5模式对RCP4.5情景下未来气候变化的预估，提出了CNOP-P类型气候变化方案，以探究在我国3H地区SSM对气候变化的潜在最大响应。与传统的假定类型气候变化方案不同，CNOP-P类型气候变化方案考虑了气候变率的变化，并引起研究区域内SSM的最大变化幅度。通过对比假定类型和CNOP-P类型气候变化方案下SSM变化的差异，我们发现，仅当降水改变时，这种差异才比较明显，且该差异主要集中在3H地区北部的半干旱区域。这表明在半干旱地区SSM对降水变率更为敏感。