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- Title
Investigating temporal field sampling strategies for site-specific calibration of three soil moisture -- neutron intensity parameterisation methods.
- Authors
Iwema, J.; Rosolem, R.; Baatz, R.; Wagener, T.; Bogena, H. R.
- Abstract
The Cosmic-Ray Neutron Sensor (CRNS) can provide soil moisture information at scales relevant to hydrometeorological modeling applications. Site-specific calibration is needed to translate CRNS neutron intensities into sensor footprint average soil moisture contents. We investigated temporal sampling strategies for calibration of three CRNS parameterisations (modified N0, HMF, and COSMIC) by assessing the effects of the number of sampling days and soil wetness conditions on the performance of the calibration results, for three sites with distinct climate and land use: a semi-arid site, a temperate grassland and a temperate forest. When calibrated with a year of data, COSMIC performed relatively good at all three sites, and the modified N0 method per- formed best at the two humid sites. It is advisable to collect soil moisture samples on more than a single day regardless of which parameterisation is used. In any case, sampling on more than ten days would, despite the strong increase in work effort, improve calibration results only little. COSMIC needed the least number of days at each site. At the semi-arid site, the N0mod method was calibrated better under average wetness conditions, whereas HMF and COSMIC were calibrated better under drier conditions. Average soil wetness condition gave better calibration results at the two humid sites. The calibration results for the HMF method were better when calibrated with combinations of days with similar soil wetness conditions, opposed to N0mod and COSMIC, which profited from using days with distinct wetness conditions. The outcomes of this study can be used by researchers as a CRNS calibration strategy guideline.
- Subjects
COSMIC ray neutrons; HYDROMETEOROLOGY; HYDROLOGIC models; CLIMATE change; HUMIDITY; PARAMETER estimation
- Publication
Hydrology & Earth System Sciences Discussions, 2015, Vol 12, Issue 2, p2349
- ISSN
1812-2108
- Publication type
Article
- DOI
10.5194/hessd-12-2349-2015