Daily Dynamic Change of Soil Moisture in the Forestlands with Typical Vegetation Forms before and after Rainfall in the Mountainous Area of West Hunan

The problem of groundwater is very prominent in super-long tunnel construction, which brings serious potential safety hazards and economic losses to the project. The knowledge of dynamic change characteristics of groundwater and prediction of water inflow is the key to ensure rational design and safe construction in super-long tunnel. In this paper, numerical simulation and in situ observation are conducted to investigate dynamic change characteristics of groundwater and the prediction of water inflow based on the Daxiangling tunnel in Sichuan Province of China. The results show that the numerical model established with detailed geological data and validated with field monitoring data can effectively analyze dynamic change characteristics of groundwater, as well as predict water inflow. The initial state of groundwater is steady when the tunnel is unexcavated. Tunnel excavation has a significant influence on the distribution of groundwater. The flow direction of groundwater will change, and the contour lines of groundwater will be intensive at the tunnel face. These changes will be more obvious and dramatic when the tunnel is excavated into the fault zone, which is a signal that the water inrush is more likely to occur in the fault zone because of a lot of joints and fractures. A connected linear cavity is formed with tunnel holing-through and groundwater begins to flow vertically downwards to the tunnel. As far as the prediction of water inflow is concerned, the numerical method can more precisely calculate the value of water inflow with less than 15 percent relative error compared with the groundwater dynamics method.

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Combined use of Sentinel SAR and optical data for soil moisture estimation

10.5194/egusphere-egu2020-722 ◽

2020 ◽

Author(s):

Giulia Graldi ◽

Simone Bignotti ◽

Marco Bezzi ◽

Alfonso Vitti

Keyword(s):

Land Use ◽

Soil Moisture ◽

Case Studies ◽

Agricultural Land ◽

Physiological State ◽

European Space Agency ◽

Irrigation Scheduling ◽

Optical Data ◽

Agricultural Land Use ◽

Mountainous Area

This work investigates the performance of two soil moisture retrieval methods using optical and radar satellite data. The study was conducted in areas with predominant agricultural land use since soil moisture is one of the parameters of interest in a wider study for water resource optimization in agricultural practices such as irrigation scheduling. The two methods considered are based on the identification of changes in the investigated parameter between two acquisition dates. The implemented methods have been applied to study areas characterized by different orographic complexity and land use heterogeneity. Data from the European Space Agency (ESA) Sentinel 1 and Sentinel 2 missions were used, and results were validated with field measurements from the International Soil Moisture Network (ISMN). At first, the methods were applied in a mountainous area of an irrigation consortium in Trentino (Italy), where the results pointed out the complexity of the study and the limitations of the current models in these contexts. Factors such as orographic complexity, type and physiological state of crops make the reduction of SAR data particularly complex to model. The methods were then tested in a simpler orographic context such as that of the Po Valley in Bologna (Italy), also characterized by agricultural land use. Finally, the methods were applied in a lowland with agricultural vocation located in Spain, for which an extended archive of soil moisture measurements distributed by the ISMN is available. In this context, the models were analyzed and were evaluated both functional and parametric adjustments of the models on the basis of the previous case studies. Some of the results obtained are of high quality, while others highlight the complexity of the problem faced and the need for further investigation: increasing the number of case studies and using optical or SAR vegetation index different from the mainly used NDVI, could enhanced the models used for soil moisture retrieval.

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An evaluation of ASCAT surface soil moisture products with in-situ observations in Southwestern France

Hydrology and Earth System Sciences ◽

10.5194/hess-13-115-2009 ◽

2009 ◽

Vol 13 (2) ◽

pp. 115-124 ◽

Cited By ~ 158

Author(s):

C. Albergel ◽

C. Rüdiger ◽

D. Carrer ◽

J.-C. Calvet ◽

N. Fritz ◽

...

Keyword(s):

Soil Moisture ◽

Surface Soil ◽

Mountainous Area ◽

Surface Soil Moisture ◽

Water Index ◽

In Situ Observations ◽

Weather Stations ◽

Term Data

Abstract. A long term data acquisition effort of profile soil moisture is currently underway at 13 automatic weather stations located in Southwestern France. In this study, the soil moisture measured in-situ at 5 cm is used to evaluate the normalised surface soil moisture (SSM) estimates derived from coarse-resolution (25 km) active microwave data of the ASCAT scatterometer instrument (onboard METOP), issued by EUMETSAT for a period of 6 months (April–September) in 2007. The seasonal trend is removed from the satellite and in-situ time series by considering scaled anomalies. One station (Mouthoumet) of the ground network, located in a mountainous area, is removed from the analysis as very few ASCAT SSM estimates are available. No correlation is found for the station of Narbonne, which is close to the Mediterranean sea. On the other hand, nine stations present significant correlation levels. For two stations, a significant correlation is obtained when considering only part of the ASCAT data. The soil moisture measured in-situ at those stations, at 30 cm, is used to estimate the characteristic time length (T) of an exponential filter applied to the ASCAT product. The best correlation between a soil water index derived from ASCAT and the in-situ soil moisture observations at 30 cm is obtained with a T-value of 14 days.

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The Diurnal Cycle of Land–Atmosphere Interactions across Oklahoma’s Winter Wheat Belt

Monthly Weather Review ◽

10.1175/mwr-2842.1 ◽

2005 ◽

Vol 133 (1) ◽

pp. 120-130 ◽

Cited By ~ 15

Author(s):

Matthew J. Haugland ◽

Kenneth C. Crawford

Keyword(s):

Soil Moisture ◽

Winter Wheat ◽

Surface Pressure ◽

Diurnal Cycle ◽

Wheat Crop ◽

Near Surface ◽

Diurnal Cycles ◽

Dewpoint Temperature ◽

Before And After ◽

The Impact

Abstract This manuscript documents the impact of Oklahoma’s winter wheat belt (WWB) on the near-surface atmosphere by comparing the diurnal cycle of meteorological conditions within the WWB relative to conditions in adjacent counties before and after the wheat harvest. To isolate the impact of the winter wheat belt on the atmosphere, data from several meteorological parameters were averaged to create a diurnal cycle before and after the wheat harvest. Observations from 17 Oklahoma Mesonet sites within the WWB (during a period of 9 yr) were compared with observations from 22 Mesonet sites in adjacent counties outside the winter wheat belt. The average diurnal cycles of dewpoint, temperature, and surface pressure exhibited patterns that revealed a distinct mesoscale impact of the wheat fields. The diurnal patterns were consistent with the status of the wheat crop and the grassland in adjacent counties. The impact of the WWB was shown to be more significant during a month when soil moisture was abundant, and minimal during a month when soil moisture was limited. Statistically significant, hydrostatically consistent afternoon surface pressure anomalies suggest that there is a strong possibility of weak mesoscale circulations induced by the WWB.

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Research on geo-ecological restoration of mountain towns upon the influence of earthquake disaster. A case study of 4.20 Lushan Earthquake

Proceedings of the 56th ISOCARP World Planning Congress ◽

10.47472/lzak8080 ◽

2020 ◽

Author(s):

Na An ◽

◽

Wei Zeng ◽

Binman Yang ◽

◽

...

Keyword(s):

Ecological Restoration ◽

Ecological Footprint ◽

Comprehensive Evaluation ◽

Evaluation Model ◽

Dynamic Change ◽

Lushan Earthquake ◽

Ecological Environment ◽

Destructive Effect ◽

Factors Affecting ◽

Before And After

Earthquakes have a great destructive effect on the geo-ecological environment of mountain towns, and the restoration of the geo-ecological environment after the disaster is of great significance to the sustainable development of mountain towns. This paper applies the improved ecological footprint method to build a geo-ecological restoration footprint evaluation model from the aspects of factors affecting the geological ecology. Moreover, Comprehensive evaluation of geo-ecology were selected to analyse the dynamic change process of geological ecology before and after the Lushan earthquake in 2010-2017. The results show that earthquake disasters have a long-term and dual impact on the geo-ecological environment of mountainous towns. Earthquake disasters can change the geo-ecological footprint by reducing the output of ecological products, changing the population composition, diet structure and even the fuel ratio, thereby affecting the geo-ecological restoration process for a long time. On the one hand, the effect of sustainable restoration of the ecology after the disaster in Lushan County has achieved initial results, the geo-ecological deficit has been reduced by more than 43%. But on the other hand, the comprehensive evaluation of ecological restoration in Lushan County is in an unsustainable state and the geo-ecological environment is facing tremendous pressure. Based on this, this article considers the degree of geoecological restoration in Lushan County, and proposes a countermeasure for future geological and ecological restoration in Lushan County.

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Atrazine Adsorption on Soil as Influenced by Temperature, Moisture Content and Electrolyte Concentration

Weed Science ◽

10.1017/s004317450004995x ◽

1978 ◽

Vol 26 (3) ◽

pp. 303-308 ◽

Cited By ~ 37

Author(s):

T. H. Dao ◽

T. L. Lavy

Keyword(s):

Soil Moisture ◽

Moisture Content ◽

Soil Solution ◽

Adsorption Isotherms ◽

Soil Moisture Content ◽

Electrolyte Concentration ◽

Thermodynamic Quantities ◽

Endothermic Reaction ◽

Freundlich Equation ◽

Before And After

The adsorption of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] was measured on soil at water:soil ratio of 5:1 and 0.4:1. The adsorption isotherms for atrazine were described by the Freundlich equation. A decrease in water:soil ratio and in soil moisture content led to an increased adsorption of the herbicide. Increasing the concentration of electrolytes in the soil solution by adding solutions up to 0.1M CaCl2increased atrazine adsorption. Greater amounts of atrazine were adsorbed at 30 than at 5 C on four soils at 0.1 bar moisture content. This indicates an endothermic reaction which was observed both before and after correction for differential atrazine solubility due to temperature. Thermodynamic quantities associated with the adsorption reaction were calculated to characterize the adsorption of atrazine on soil.

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Winter wheat and maize under varying soil moisture: from leaf to canopy

10.5194/egusphere-egu21-11716 ◽

2021 ◽

Author(s):

Thuy Huu Nguyen ◽

Matthias Langensiepen ◽

Thomas Gaiser ◽

Heidi Webber ◽

Hella Ahrends ◽

...

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Winter Wheat ◽

Leaf Area ◽

Dynamic Change ◽

Crop Growth ◽

Leaf Water ◽

Area Index ◽

Canopy Transpiration ◽

Stomatal Responses

Drought is one of the most detrimental factors limiting crop growth and production of important staple crops such as winter wheat and maize. For both crops, stomatal regulation and change of canopy structure responses to water stress can be observed. A substantial range of stomatal behavior in regulating water loss was recently reported while the crop growth and morphological responses to drought stress depend on the intensity and duration of the imposed stress. Insights into the responses from leaf to the canopy are important for crop modeling and soil-vegetation-atmosphere models (SVAT). Stomatal responses and effects of soil water deficit on the dynamic change of canopy photosynthesis and transpiration, and seasonal crop growth of winter wheat and maize are investigated based on data collected from field-grown conditions with varying soil moisture treatments (sheltered, rainfed, irrigated) in 2016, 2017, and 2018. A reduction of leaf net photosynthesis (An), stomatal conductance (Gs), transpiration (E), and leaf water potential (LWP) was observed in the sheltered plot as compared to the rainfed and irrigated plots in winter wheat in 2016, indicating anisohydric stomatal responses. Maize showed seasonal isohydric behaviour with the minimum LWP from -1.5 to -2 MPa in 2017 and -2 to -2.7 MPa in the extremely hot and dry year in 2018. Crop growth (biomass, leaf area index, and yield) was substantially reduced under drought conditions, particularly for maize in 2018. Leaf water use efficiency (An/E) and crop WUE (total dry biomass/canopy transpiration) were not significantly different among treatments in both crops. The reduction of tiller number (in winter wheat) and leaf-rolling and plant size (in maize) resulted in a reduction of canopy transpiration, assimilation rate, and thus biomass. The seasonal isohydry in maize and the seasonal variability of LWP in winter wheat suggest a possibility to use the same critical LWP thresholds for maize and wheat to simulate the stomatal control in process-based crop and SVAT models. The canopy response such as dynamically reducing leaf area under water stress adds complexity in simulating gas exchange and crop growth rate that needs adequate consideration in the current modeling approaches.

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Evaluation of the regional climate model RegCM4.7 over the Carpathian region for very wet and average years

10.5194/egusphere-egu2020-330 ◽

2020 ◽

Author(s):

Tímea Kalmár ◽

Ildikó Pieczka ◽

Rita Pongrácz

Keyword(s):

Soil Moisture ◽

Regional Climate Model ◽

Land Surface ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Cloud Microphysics ◽

Mountainous Area ◽

Model Version ◽

Carpathian Region

Precipitation is one of the most important climate variables in many aspects due to its key impact on agriculture, water management, etc. However, it remains a challenge for climate models to realistically simulate the regional patterns, temporal variations, and intensity of precipitation. The difficulty arises from the complexity of precipitation processes within the atmosphere stemming from cloud microphysics, cumulus convection, large-scale circulations, planetary boundary layer (PBL) processes, and many others. This is especially true for heterogeneous surfaces with complex orography such as the Carpathian region. &#160;Thus, the Carpathian Basin, with its surrounding mountains, requires higher model resolution, along with different parameterizations, compared to more homogenous regions. The aim of the study is to reproduce the historical precipitation pattern through testing the parameterization of surface processes. The appropriate representations of land surface component in climate models are essential for the simulation of surface and subsurface runoff, soil moisture, and evapotranspiration. Furthermore, PBL strongly influences temperature, moisture, and wind through the turbulent transfer of air mass. The current study focuses on the newest model version of RegCM (RegCM4.7), with which we carry out simulations using different parameterization schemes over the Carpathian region. We investigate the effects of land-surface schemes (i.e. BATS - Biosphere-Atmosphere Transfer Scheme and CLM4.5 - Community Land Model version 4.5) in the regional climate model. Studies over different regions have shown that CLM offers improvements in terms of land&#8211;atmosphere exchanges of moisture and energy and associated surface climate feedbacks compared with BATS. Our aim includes evaluating whether this is the case for the Carpathian region.Four 1-year-long experiments both for 1981 and 2010 (excluding the spin-up time) are completed using the same domain, initial and lateral atmospheric boundary data conditions (i.e. ERA-Interim), with a 10 km spatial resolution. These years were chosen because 1981 was a normal year in terms of precipitation, while 2010 was the wettest year in Hungary from the beginning of the 20th century. We carry out a detailed analysis of RegCM outputs focusing not only on standard climatological variables (precipitation and temperature), but also on additional meteorological variables, which have important roles in the water cycle (e.g. soil moisture, evapotranspiration). The simulations are compared with the CARPATCLIM observed, homogenised, gridded dataset and other databases (ESA CCI Soil Moisture Product New Version Release (v04.5) and Surface Solar Radiation Data Set - Heliosat (SARAH)). It is found that the simulated near-surface temperature and precipitation are better represented in the CLM scheme than in the BATS when compared with observations, both over the lowland and mountainous area. The model simulations also show that the precipitation is overestimated more over mountainous area in 2010 than in 1981.&#160;&#160;

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Flood Effects on the Phytoplankton Diversity of Bega River (Banat, Romania)

Transylvanian Review of Systematical and Ecological Research ◽

10.2478/trser-2013-0042 ◽

2013 ◽

Vol 15 (3) ◽

pp. 207

Author(s):

Hanelore Muntean ◽

Laura Alexoaie

Keyword(s):

Water Body ◽

Nutrient Balance ◽

Water System ◽

Mountainous Area ◽

Phytoplankton Diversity ◽

Before And After ◽

High Precipitation ◽

Local Water ◽

Flooded Area ◽

Water Administration

ABSTRACT Situated on the Western Plains of Romania, the Banat region has an adverse natural condition that makes it a frequently-flooded area. A lack of natural drainage due to a low slope, shallow gound water, slow-moving water course densities, and precipitation in this close, mountainous area all contribute to periodic flood events. Water courses in the region have snake-like river beds and swamps present in the area before the XVIIIth century (Griselini, 1979) also create a tendency toward flood activity. The Bega is a river in the Timiș- Bega water system, originating from Poiana Rusca Mountains and the lower basin becomes channeled before entering Timișoara City. Seasonal floods and overall water quality influence the quantity and quality of phytoplankton and macrozoobenthos in the Bega River. Phytoplankton obtains energy through the process of photosynthesis and must therefore live in the well-lit surface layer of a water body. Crucially dependent on minerals, phytoplankton primarily subsist on macronutrients such as nitrate, phosphate or silicic acid, which are governed by the balance between the socalled biological pump and the upwelling of deep, nutrient-rich waters. After floods the balance of nutrients in a river is changed and the effects can be observed by discerning differences in phytoplankton biomass and families living in the water body before and after the flood event (Muzaffar, 2007). In this study, based on the information from local water administration, we provide data about the flood in 2005 and its effects on the biodiversity in the river. The measurements were made at 2 sites, one before the Bega River enters Timișoara and the other at Otelec station, 45.5 km downstream from Timișoara. The runoff in 2005, caused by high precipitation in the upper basin, disturbed the nutrient balance in the river by transporting debris and sediment discharge from upstream, and carrying the local macrozoobenthos out of their normal habitat. Upstream from Timișoara, phytoplankton is dominated by species of diatomes like Diatoma sp., Synedra sp., Navicula sp., Fragilaria sp., Rhoicospahenia sp., Gyrosigma sp., Cymatopleura sp. and Amphora sp. During floods the flow and speed of the water increases, which dilutes the water and modifies the concentration of nutrients and pollutants in the affected area, therefore changing the processes at a biological level. This specific process is important for the possibility of selfpurification in water bodies.

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