Spatial and Temporal Soil Moisture Variations over China from Simulations and Observations

Jun Wen,Xiaokang Shi,Xin Lai,Sixian Cen,Hui Tian,Xi Huang

doi:10.1155/2016/4587687

Abstract

The Community Land Model version 4.0 (CLM4.0) driven by the forcing data of Princeton University was used to simulate soil moisture (SM) from 1961 to 2010 over China. The simulated SM was compared to the in situ SM measurements from International Soil Moisture Network over China, National Centers for Environmental Prediction (NCEP) Reanalysis data, a new microwave based multiple-satellite surface SM dataset (SM-MW), and European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA Interim/Land) SM data. The results showed that CLM4.0 simulation is capable of capturing characteristics of the spatial and temporal variations of SM. The simulated, NCEP, SM-MW, and ERA Interim/Land SM products are reasonably consistent with each other; based on the simulated SM of summer, it can be concluded that the spatial distribution in every layer was characterized by a gradually increasing pattern from the northwest to southeast. The SM increased from surface layer to deeper layer in general. The variation trends basically showed consistencies at all depths. The simulated SM of summer demonstrated different responses to the precipitation variation. The variation distribution of SM and measured precipitation had consistencies. The humid region significantly responded to precipitation, while the semiarid and arid regions were ranked second.

Highlights

Soil moisture (SM) is one of the most important geophysical variables for characterizing the status of the land surface, and it is an important variable that controls the landatmosphere interaction
The simulated SM was compared to the ground observations, National Centers for Environmental Prediction (NCEP) Reanalysis data, and SMMW and ERA Interim/Land SM data
The simulated SM was compared to the ground observations, NCEP Reanalysis, SM-MW, and ERA Interim/Land SM data

Summary

Introduction

Soil moisture (SM) is one of the most important geophysical variables for characterizing the status of the land surface, and it is an important variable that controls the landatmosphere interaction. By running the Community Land Model (CLM3.5) over China from 1993 to 2002 using the reanalysis-based precipitation and air temperature and in situ observations in the meteorological forcing dataset, Wang and Zeng [6] discussed the effects of the quality of meteorological forcing data (such as precipitation and temperature) on the simulations of variables in the land surface water cycle. Li et al [1] generated an atmospheric field (ObsFC) for the Community Land Model version 3.5 (CLM3.5) with the support from ground station observations, and SM was simulated over China from 1951 to 2008. The spatial and temporal variations of SM and its response to climate change over China during 1961–2010 will be explored, the shortage of CLM4.0 simulation over China will be summarized and discussed, and the future improvements of the scheme will be prospected

Model and Data

Data Description

Validation of Simulations

Discussion

Conclusion