Land surface model performance using cosmic-ray and point-scale soil moisture measurements for calibration

Iwema, Joost; Rosolem, Rafael; Rahman, Mostaquimur; Blyth, Eleanor ORCID: https://orcid.org/0000-0002-5052-238X; Wagener, Thorsten. 2017 Land surface model performance using cosmic-ray and point-scale soil moisture measurements for calibration. Hydrology and Earth System Sciences, 21 (6). 2843-2861. 10.5194/hess-21-2843-2017

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Abstract/Summary

At very high resolution scale (i.e. grid cells of 1 km2), land surface model parameters can be calibrated with eddy-covariance flux data and point-scale soil moisture data. However, measurement scales of eddy-covariance and point-scale data differ substantially. In our study, we investigated the impact of reducing the scale mismatch between surface energy flux and soil moisture observations by replacing point-scale soil moisture data with observations derived from Cosmic-Ray Neutron Sensors (CRNSs) made at larger spatial scales. Five soil and evapotranspiration parameters of the Joint UK Land Environment Simulator (JULES) were calibrated against point-scale and Cosmic-Ray Neutron Sensor soil moisture data separately. We calibrated the model for 12 sites in the USA representing a range of climatic, soil, and vegetation conditions. The improvement in latent heat flux estimation for the two calibration solutions was assessed by comparison to eddy-covariance flux data and to JULES simulations with default parameter values. Calibrations against the two soil moisture products alone did show an advantage for the cosmic-ray technique. However, further analyses of two-objective calibrations with soil moisture and latent heat flux showed no substantial differences between both calibration strategies. This was mainly caused by the limited effect of calibrating soil parameters on soil moisture dynamics and surface energy fluxes. Other factors that played a role were limited spatial variability in surface fluxes implied by soil moisture spatio-temporal stability, and data quality issues.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/hess-21-2843-2017
UKCEH and CEH Sections/Science Areas:	Reynard
ISSN:	1027-5606
Additional Information. Not used in RCUK Gateway to Research.:	Open Access paper - full text available via Official URL link.
NORA Subject Terms:	Agriculture and Soil Science Atmospheric Sciences
Date made live:	08 Aug 2017 09:10 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/517491

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