scholarly journals Integral quantification of seasonal soil moisture changes in farmland by cosmic-ray neutrons

2011 ◽  
Vol 15 (12) ◽  
pp. 3843-3859 ◽  
Author(s):  
C. A. Rivera Villarreyes ◽  
G. Baroni ◽  
S. E. Oswald
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
Meteorological Data ◽  
Cosmic Ray ◽  
Winter Period ◽  
Agricultural Field ◽  
Substantial Impact ◽  
Hill Slope ◽  
Measurement Methodology ◽  
Crop Biomass

Abstract. Soil moisture at the plot or hill-slope scale is an important link between local vadose zone hydrology and catchment hydrology. However, so far only a few methods are on the way to close this gap between point measurements and remote sensing. One new measurement methodology that could determine integral soil moisture at this scale is the aboveground sensing of cosmic-ray neutrons, more precisely of ground albedo neutrons. The present study performed ground albedo neutron sensing (GANS) at an agricultural field in northern Germany. To test the method it was accompanied by other soil moisture measurements for a summer period with corn crops growing on the field and a later autumn-winter period without crops and a longer period of snow cover. Additionally, meteorological data and aboveground crop biomass were included in the evaluation. Hourly values of ground albedo neutron sensing showed a high statistical variability. Six-hourly values corresponded well with classical soil moisture measurements, after calibration based on one reference dry period and three wet periods of a few days each. Crop biomass seemed to influence the measurements only to minor degree, opposed to snow cover which has a more substantial impact on the measurements. The latter could be quantitatively related to a newly introduced field neutron ratio estimated from neutron counting rates of two energy ranges. Overall, our study outlines a procedure to apply the ground albedo neutron sensing method based on devices now commercially available, without the need for accompanying numerical simulations and suited for longer monitoring periods after initial calibration.

scholarly journals Integral quantification of seasonal soil moisture changes in farmland by cosmic-ray neutrons

2011 ◽  
Vol 8 (4) ◽  
pp. 6867-6906 ◽  
Author(s):  
C. A. Rivera Villarreyes ◽  
G. Baroni ◽  
S. E. Oswald
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
Meteorological Data ◽  
Cosmic Ray ◽  
Winter Period ◽  
Agricultural Field ◽  
Substantial Impact ◽  
Hill Slope ◽  
First Time ◽  
Crop Biomass

Abstract. The measurement of soil moisture at the plot or hill-slope scale is an important link between local vadose zone hydrology and catchment hydrology. However, so far only a few methods are on the way to close this gap between point measurements and remote sensing. One method that could determine an integral soil moisture at this scale is the so called cosmic ray sensing that was introduced to soil hydrology very recently the first time. The present study performed cosmic ray sensing at an agricultural field in a Central European lowland. To test the method it was accompanied by other soil moisture measurements for a summer period with corn crops growing on the field and a later autumn-winter period without crops and a longer period of snow cover. Additionally, meteorological data and above-ground crop biomass was included into the evaluation. Hourly values of cosmic ray sensing showed a high statistical variability. Six-hourly values corresponded well with classical soil moisture measurements, after calibration based on one dry and three wet periods of a few days each. Crop biomass seemed to influence the measurements only to minor degree, opposed to snow cover which has a more substantial impact on the measurements. The latter could be quantitatively related to count rates in two different variants of cosmic ray counters. Overall, our study outlines a procedure to apply the cosmic ray sensing method based on devices now commercially available, without the need for accompanying numerical simulations and suited for longer monitoring periods after initial calibration.

scholarly journals Calibration approaches of cosmic-ray neutron sensing for soil moisture measurement in cropped fields

2013 ◽  
Vol 10 (4) ◽  
pp. 4237-4274 ◽  
Author(s):  
C. A. Rivera Villarreyes ◽  
G. Baroni ◽  
S. E. Oswald
Keyword(s):  
Soil Moisture ◽  
Cosmic Ray ◽  
Fast Neutrons ◽  
Winter Rye ◽  
Moisture Profile ◽  
Hill Slope ◽  
Vadose Zone Hydrology ◽  
Classical Point ◽  
Soil Moisture Measurement ◽  
Single Set

Abstract. Measurement of soil moisture at the plot or hill-slope scale is an important link between local vadose-zone hydrology and catchment hydrology. This study evaluates the applicability of the cosmic-ray neutron sensing for soil moisture in cropped fields. Measurements of cosmic-ray neutrons (fast neutrons) were performed at a lowland farmland in Bornim (Brandenburg, Germany) cropped with sunflower and winter rye. Three field calibration approaches and four different ways of integration the soil moisture profile to an integral value for cosmic-ray neutron sensing were evaluated in this study. The cosmic-ray sensing (CRS) probe was calibrated against a network of classical point-scale soil moisture measurements. A large CRS parameter variability was observed by choosing calibration periods within the different growing stages of sunflower and winter rye. Therefore, it was not possible to identify a single set of parameters perfectly estimating soil moisture for both sunflower and winter rye periods. On the other hand, CRS signal and its parameter variability could be understood by some crop characteristics and by predicting the attenuated neutrons by crop presence. This study proves the potentiality of the cosmic-ray neutron sensing at the field scale; however, its calibration needs to be adapted for seasonal vegetation in cropped fields.

scholarly journals Soil moisture observation in a forested headwater catchment: combining a dense cosmic-ray neutron sensor network with roving and hydrogravimetry at the TERENO site Wüstebach

2021 ◽  
Author(s):  
Maik Heistermann ◽  
Heye Bogena ◽  
Till Francke ◽  
Andreas Güntner ◽  
Jannis Jakobi ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Sensor Network ◽  
Root Zone ◽  
Water Storage ◽  
Cosmic Ray ◽  
Water Dynamics ◽  
Catchment Scale ◽  
Small Catchment ◽  
Hill Slope ◽  
The Hill

Abstract. Cosmic Ray Neutron Sensing (CRNS) has become an effective method to measure soil moisture at a horizontal scale of hundreds of meters and a depth of decimeters. Recent studies proposed to operate CRNS in a network with overlapping footprints in order to cover root-zone water dynamics at the small catchment scale, and, at the same time, to represent spatial heterogeneity. In a joint field campaign from September to November 2020 (JFC-2020), five German research institutions deployed 15 CRNS sensors in the 0.4 km2 Wüstebach catchment (Eifel mountains, Germany). The catchment is dominantly forested (but includes a substantial fraction of open vegetation), and features a topographically distinct watershed. In addition to the dense CRNS coverage, the campaign featured a unique combination of additional instruments and techniques: hydro-gravimetry (to detect water storage dynamics also below the root zone); ground-based and, for the first time, airborne CRNS roving; an extensive wireless soil sensor network, supplemented by manual measurements; and six weighable lysimeters. Together with comprehensive data from the long-term local research infrastructure, the published dataset (available at https://doi.org/10.23728/b2share.afb20a34a6ac429ca6b759238d842765) will be a valuable asset in various research contexts: to advance the retrieval of landscape water storage from CRNS, wireless soil sensor networks, or hydrogravimetry; to identify scale-specific combinations of sensors and methods to represent soil moisture variability; to improve the understanding and simulation of land-atmosphere exchange as well as hydrological and hydrogeological processes at the hill-slope and the catchment scale; and to support the retrieval soil water content from airborne and spaceborne remote sensing platforms.

Influence of autumn soil moisture on erosion-accumulation processes in the Krasnoyarsk forest-steppe

2021 ◽  
pp. 130-142
Author(s):  
I.A. Golubev ◽  
◽  
A.V. Kozhukhovsky ◽  
O.I. Ivanova ◽  
◽  
...  
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
Water Permeability ◽  
Soil Surface ◽  
Winter Period ◽  
Forest Steppe ◽  
Field Observations ◽  
Runoff Formation ◽  
Northern Zone ◽  
Hydrometeorological Conditions

The results of field observations of erosion-accumulation processes caused by meltwater in the northern zone of the Krasnoyarsk forest-steppe in 2009-2017 are discussed. Hydrometeorological conditions of melt runoff formation during the study period and their influence on the values of washout and accumulation are analyzed. Data on snow cover, soil moisture in the pre-winter period, meltwater flow to the soil surface, and spring and autumn runoff are compared. Attention is focused on the autumn soil moisture. The correlation between the values of washout and preceding autumn moisture is revealed. Other things being equal, among all hydrometeorological factors on the territory of the Krasnoyarsk forest-steppe, pre-winter soil moisture has a significant impact on the intensity of erosion-accumulation processes. Keywords: soil washout, erosion, autumn moisture, hydrometeorological factors, runoff, snow cover, humidity, freezing, water permeability

scholarly journals Temporal stability of soil moisture patterns measured by proximal ground-penetrating radar

2013 ◽  
Vol 10 (4) ◽  
pp. 4063-4097 ◽  
Author(s):  
J. Minet ◽  
N. E. C. Verhoest ◽  
S. Lambot ◽  
M. Vanclooster
Keyword(s):  
Soil Moisture ◽  
Real Time ◽  
Ground Penetrating Radar ◽  
Meteorological Data ◽  
Single Point ◽  
Temporal Stability ◽  
Soil Core ◽  
Agricultural Field ◽  
Ground Penetrating ◽  
Field Area

Abstract. We analyzed the temporal stability of soil moisture patterns acquired using a proximal ground-penetrating radar (GPR) in a 2.5 ha agricultural field at five different dates over three weeks. The GPR system was mounted on a mobile platform, allowing for real-time mapping of soil moisture with a high spatial resolution (2–5 m). The spatio-temporal soil moisture patterns were in accordance with the meteorological data and with soil moisture measurements from soil core sampling. Time-stable areas showing the field-average moisture could be revealed by two methods: (1) by the computation of temporal stability indicators based on relative differences of soil moisture to the field-average and (2) by the spatial intersection of the areas showing the field-average. Locations where the mean relative difference was below 0.02 m3 m−3 extended up to 10% of the field area whereas the intersection of areas showing the field-average within a tolerance of 0.02 m3 m−3 covered 5% of the field area. Compared to most of the previous studies about temporal stability of soil moisture, time-stable areas and their spatial patterns could be revealed instead of single point locations, owing to the advanced GPR method for real-time mapping. It is believed that determining spatially coherent time-stable areas is more informative rather than determining time-stable points. Other acquisitions over larger time periods would be necessary to assert the robustness of the time-stable areas.

scholarly journals Regression Models for Soil Water Storage Estimation Using the ESA CCI Satellite Soil Moisture Product: A Case Study in Northeast Portugal

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 37
Author(s):  
Tomás de Figueiredo ◽  
Ana Caroline Royer ◽  
Felícia Fonseca ◽  
Fabiana Costa de Araújo Schütz ◽  
Zulimar Hernández
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Regression Models ◽  
Meteorological Data ◽  
Water Storage ◽  
Model Performance ◽  
Soil Water Balance ◽  
Soil Water Storage ◽  
The Relationship

The European Space Agency Climate Change Initiative Soil Moisture (ESA CCI SM) product provides soil moisture estimates from radar satellite data with a daily temporal resolution. Despite validation exercises with ground data that have been performed since the product’s launch, SM has not yet been consistently related to soil water storage, which is a key step for its application for prediction purposes. This study aimed to analyse the relationship between soil water storage (S), which was obtained from soil water balance computations with ground meteorological data, and soil moisture, which was obtained from radar data, as affected by soil water storage capacity (Smax). As a case study, a 14-year monthly series of soil water storage, produced via soil water balance computations using ground meteorological data from northeast Portugal and Smax from 25 mm to 150 mm, were matched with the corresponding monthly averaged SM product. Linear (I) and logistic (II) regression models relating S with SM were compared. Model performance (r2 in the 0.8–0.9 range) varied non-monotonically with Smax, with it being the highest at an Smax of 50 mm. The logistic model (II) performed better than the linear model (I) in the lower range of Smax. Improvements in model performance obtained with segregation of the data series in two subsets, representing soil water recharge and depletion phases throughout the year, outlined the hysteresis in the relationship between S and SM.

Moisture and humidity dependence of the above-ground cosmic-ray neutron intensity revised

2021 ◽  
Author(s):  
Markus Köhli ◽  
Jannis Weimar ◽  
Benjamin Fersch ◽  
Roland Baatz ◽  
Martin Schrön ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Soil Moisture ◽  
Count Rate ◽  
Cosmic Ray ◽  
Mathematical Treatment ◽  
Specific Response ◽  
Parameter Equation ◽  
Neutron Count ◽  
Dry Conditions ◽  
Humidity Dependence

<p>The novel method of Cosmic-ray neutron sensing (CRNS) allows non-invasive soil moisture measurements at a hectometer scaled footprint. Up to now, the conversion of soil moisture to a detectable neutron count rate relies mainly on the equation presented by Desilets et al. (2010). While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterisation needs to be revised for two reasons. Firstly, a rigorous mathematical treatment reveals that the values of the four parameters are ambiguous because their values are not independent. We find a 3-parameter equation with unambiguous values of the parameters which is equivalent in any other respect to the 4-parameter equation. Secondly, high-resolution Monte-Carlo simulations revealed a systematic deviation of the count rate to soil moisture relation especially for extremely dry conditions as well as very humid conditions. That is a hint, that a smaller contribution to the intensity was forgotten or not adequately treated by the conventional approach. Investigating the above-ground neutron flux by a broadly based Monte-Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies including the effect of different hydrogen pools and the detector-specific response function. The new relationship has been tested at three exemplary measurement sites and its remarkable performance allows for a promising prospect of more comprehensive data quality in the future.</p>

Soil moisture assessment based on Sentinel 1/2 and in-situ data: The vineyard case study

2021 ◽  
Author(s):  
Maria Paula Mendes ◽  
Ana Paula Falcão ◽  
Magda Matias ◽  
Rui Gomes
Keyword(s):  
Soil Moisture ◽  
Climate Models ◽  
Root Zone ◽  
Irrigation Management ◽  
Management Strategies ◽  
Winter Period ◽  
Classification Algorithms ◽  
Precipitation Regime ◽  
Terrain Attributes ◽  
Sentinel 2

<p>Vineyards are crops whose production has a major economic impact in the Portuguese economy (~750 million euros) being exported worldwide. As the climate models project a larger variability in precipitation regime, the water requirements of vineyards can change and drip irrigation can be responsible for salt accumulation in the root zone, especially when late autumn and winter precipitation is not enough to leach salts from the soil upper horizons, turning the soil unsuitable for grape production.</p><p>The aim of this work is to present a methodology to map surface soil moisture content (SMC) in a vineyard, (40 hectares) based on the application of two classification algorithms to satellite imagery (Sentinel 1 and Sentinel 2). Two vineyard plots were considered and three field campaigns (December 2017, January 2018 and May 2018) were conducted to measure soil moisture contents (SMC). A geostatistical method was used to estimate the SM class probabilities according to a threshold value, enlarging the training set (i.e., SMC data of the two plots) for the classification algorithms. Sentinel-1 and Sentinel-2 images and terrain attributes fed the classification algorithms. Both methods, Random Forest and Logistic Regression, classified the highest SMC areas, with probabilities above 14%, located close to a stream at the lower altitudes.</p><p>RF performed very well in classifying the topsoil zones with lower SMC during the autumn-winter period (F-measure=0.82).</p><p>This delineation allows the prevention of the occurrence of areas affected by salinization, indicating which areas will need irrigation management strategies to control the salinity, especially under climate change, and the expected increase in droughts.</p>

scholarly journals The Strengthening Relationship between Eurasian Snow Cover and December Haze Days in Central North China after the Mid-1990s

2017 ◽  
Author(s):  
Zhicong Yin ◽  
Huijun Wang
Keyword(s):  
Soil Moisture ◽  
Snow Cover ◽  
North China ◽  
Surface Wind ◽  
Surface Radiation ◽  
Radiative Cooling ◽  
Atmospheric Circulations ◽  
Haze Pollution ◽  
The Relationship ◽  
Haze Days

Abstract. The haze pollution in December has become increasingly serious over recent decades and imposes damage on society, ecosystems, and human health. In addition to anthropogenic emissions, climate change and variability were conducive to haze in China. In this study, the relationship between the snow cover over East Europe and West Siberia (SCES) and the number of haze days in December in central North China was analyzed. This relationship significantly strengthened after the mid-1990s, which is attributed to the effective connections between the SCES and the Eurasian atmospheric circulations. During 1998–2016, the SCES significantly influenced the soil moisture and land surface radiation, and then, the combined underlying drivers of enhanced soil moisture and radiative cooling moved the East Asia jet stream northward and induced anomalous, anti-cyclonic circulation over central North China. Modulated by such atmospheric circulations, the local lower boundary layer, the decreased surface wind and the more humid air were conducive to the worsening dispersion conditions and frequent haze occurrences. In contrast, from 1979 to 1997, the linkage between the SCES and soil moisture was negligible. Furthermore, the correlated radiative cooling was distributed narrowly and far from the key area of snow cover. The associated atmospheric circulations with the SCES were not significantly linked with the ventilation conditions over central North China. Consequently, the relationship between the SCES and the number of hazy days in central North China was insignificant before the mid-1990s but has strengthened and has become significant since then.

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