Variations in soil moisture over the ‘Huang-Huai-Hai Plain’ in China due to temperature change using the CNOP-P method and outputs from CMIP5

Abstract

In this study, the variations in surface soil liquid water (SSLW) due to future climate change are explored in the ‘Huang-Huai-Hai Plain’ (‘3H’) region in China with the Common Land Model (CoLM). To evaluate the possible maximum response of SSLW to climate change, the combination of the conditional nonlinear optimal perturbation related to the parameter (CNOP-P) approach and projections from 10 general circulation models (GCMs) of the Coupled Model Intercomparison Project 5 (CMIP5) are used. The CNOP-P-type temperature change scenario, a new type of temperature change scenario, is determined by using the CNOP-P method and constrained by the temperature change projections from the 10 GCMs under a high-emission scenario (the Representative Concentration Pathway 8.5 scenario). Numerical results have shown that the response of SSLW to the CNOP-P-type temperature scenario is stronger than those to the 11 temperature scenarios derived from the 10 GCMs and from their ensemble average in the entire ‘3H’ region. In the northern region, SSLW under the CNOP-P-type scenario increases to 0.1773 m3 m‒3; however, SSLW in the scenarios from the GCMs fluctuates from 0.1671 to 0.1748 m3 m‒3. In the southern region, SSLW decreases, and its variation (–0.0070 m3 m‒3) due to the CNOP-P-type scenario is higher than each of the variations (–0.0051 to –0.0026 m3 m‒3) due to the scenarios from the GCMs.