Title
Estimating Time Series Soil Moisture by Applying Recurrent Nonlinear Autoregressive Neural Networks to Passive Microwave Data over the Heihe River Basin, China.
Abstract
A method using a nonlinear auto-regressive neural network with exogenous input (NARXnn) to retrieve time series soil moisture (SM) that is spatially and temporally continuous and high quality over the Heihe River Basin (HRB) in China was investigated in this study. The input training data consisted of the X-band dual polarization brightness temperature (TB) and the Ka-band V polarization TB from the Advanced Microwave Scanning Radiometer II (AMSR2), Global Land Satellite product (GLASS) Leaf Area Index (LAI), precipitation from the Tropical Rainfall Measuring Mission (TRMM) and the Global Precipitation Measurement (GPM), and a global 30 arc-second elevation (GTOPO-30). The output training data were generated from fused SM products of the Japan Aerospace Exploration Agency (JAXA) and the Land Surface Parameter Model (LPRM). The reprocessed fused SM from two years (2013 and 2014) was inputted into the NARXnn for training; subsequently, SM during a third year (2015) was estimated. Direct and indirect validations were then performed during the period 2015 by comparing with in situ measurements, SM from JAXA, LPRM and the Global Land Data Assimilation System (GLDAS), as well as precipitation data from TRMM and GPM. The results showed that the SM predictions from NARXnn performed best, as indicated by their higher correlation coefficients (R >= 0.85 for the whole year of 2015), lower Bias values (absolute value of Bias <= 0.02) and root mean square error values (RMSE <= 0.06), and their improved response to precipitation. This method is being used to produce the NARXnn SM product over the HRB in China.
Year
DOI
Venue
2017
10.3390/rs9060574
REMOTE SENSING
Keywords
Field
DocType
soil moisture (SM),time series,neural network of nonlinear auto-regressive models with exogenous input (NARXnn),Heihe River Basin (HRB)
Leaf area index,Global Precipitation Measurement,Satellite,Brightness temperature,Remote sensing,Mean squared error,Data assimilation,Geology,Precipitation,Radiometer
Journal
Volume
Issue
ISSN
9
6
2072-4292
Citations 
PageRank 
References 
0
0.34
15
Authors
8
Name
Order
Citations
PageRank
Zheng Lu101.69
linna chai233.20
Shaomin Liu33515.19
Huizhen Cui401.01
Yanghua Zhang500.68
Lingmei Jiang610834.89
Rui Jin79016.41
Ziwei Xu822.29