scholarly journals Hyperspectral measurements of wet, dry and saline soils from the McMurdo Dry Valleys: soil moisture properties from remote sensing

2014 ◽  
Vol 26 (5) ◽  
pp. 565-572 ◽  
Author(s):  
Joseph Levy ◽  
Anne Nolin ◽  
Andrew Fountain ◽  
James Head
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Thermal State ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Non Invasive ◽  
High Concentrations ◽  
Remote Sensing Techniques ◽  
Moisture Conditions ◽  
Chloride Salts

AbstractSoil moisture is a spatially heterogeneous quantity in the McMurdo Dry Valleys of Antarctica that exerts a large influence on the biological community and on the thermal state of Dry Valleys permafrost. The goal of this project was to determine whether hyperspectral remote sensing techniques could be used to determine soil moisture conditions in the Dry Valleys. We measured the spectral reflectance factors of wetted soil samples from the Dry Valleys under natural light conditions and related diagnostic spectral features to surface layer soil moisture content. Diagnostic water absorption features in the spectra at 1.4 µm and 1.9 µm were present in all samples, including samples doped with high concentrations of chloride salts. The depth of the 1.4 µm absorption is shown to increase linearly with increasing gravimetric water content. These results suggest that airborne hyperspectral imaging of the Dry Valleys could generate soil moisture maps of this environment over large spatial areas using non-invasive remote-sensing techniques.

Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica

2021 ◽  
pp. 1-15
Author(s):  
Joseph Levy
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Mcmurdo Dry Valleys ◽  
Limiting Factor ◽  
High Humidity ◽  
Dry Valleys ◽  
Surface Soils ◽  
Basin Scale ◽  
Soil Reflectance

Abstract Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.

scholarly journals Land-Cover Dependent Relationships between Fire and Soil Moisture

Fire ◽  
2019 ◽  
Vol 2 (4) ◽  
pp. 55 ◽  
Author(s):  
Alexander J. Schaefer ◽  
Brian I. Magi
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Land Cover ◽  
Remote Sensing Data ◽  
Sensing Data ◽  
Fire Activity ◽  
Steep Decline ◽  
Human Use ◽  
Moisture Conditions ◽  
In Fire

For this study, we characterized the dependence of fire counts (FCs) on soil moisture (SM) at global and sub-global scales using 15 years of remote sensing data. We argue that this mathematical relationship serves as an effective way to predict fire because it is a proxy for the semi-quantitative fire–productivity relationship that describes the tradeoff between fuel availability and climate as constraints on fire activity. We partitioned the globe into land-use and land-cover (LULC) categories of forest, grass, cropland, and pasture to investigate how the fire–soil moisture (fire–SM) behavior varies as a function of LULC. We also partitioned the globe into four broadly defined biomes (Boreal, Grassland-Savanna, Temperate, and Tropical) to study the dependence of fire–SM behavior on LULC across those biomes. The forest and grass LULC fire–SM curves are qualitatively similar to the fire–productivity relationship with a peak in fire activity at intermediate SM, a steep decline in fire activity at low SM (productivity constraint), and gradual decline as SM increases (climate constraint), but our analysis highlights how forests and grasses differ across biomes as well. Pasture and cropland LULC are a distinctly human use of the landscape, and fires detected on those LULC types include intentional fires. Cropland fire–SM curves are similar to those for grass LULC, but pasture fires are evident at higher SM values than other LULC. This suggests a departure from the expected climate constraint when burning is happening at non-optimal flammability conditions. Using over a decade of remote sensing data, our results show that quantifying fires relative to a single physical climate variable (soil moisture) is possible on both cultivated and uncultivated landscapes. Linking fire to observable soil moisture conditions for different land-cover types has important applications in fire management and fire modeling.

Thermal properties of Antarctic soils: wetting controls subsurface thermal state

2016 ◽  
Vol 28 (5) ◽  
pp. 361-370 ◽  
Author(s):  
Joseph S. Levy ◽  
Logan M. Schmidt
Keyword(s):  
Soil Moisture ◽  
Thermal Diffusivity ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Thermal State ◽  
Thermal Characteristics ◽  
Field Measurements ◽  
Dry Valleys ◽  
Ground Ice ◽  
Mineral Soils

AbstractMineral soils in the McMurdo Dry Valleys (MDV), Antarctica, are commonly considered to be dry, and therefore to be good insulators with low thermal diffusivity values (~0.2 mm2s-1). However, field measurements of soil moisture profiles with depth, coupled with observations of rapid ground ice melt, suggest that the thermal characteristics of MDV soils, and thus their resistance to thaw, may be spatially variable and strongly controlled by soil moisture content. The thermal conductivity, heat capacity and thermal diffusivity of 17 MDV soils were measured over a range of soil moisture conditions from dry to saturated. We found that thermal diffusivity varied by a factor of eight for these soils, despite the fact that they consist of members of only two soil groups. The thermal diffusivity of the soils increased in all cases with increasing soil moisture content, suggesting that permafrost and ground ice thaw in mineral soils may generate a positive thawing feedback in which wet soils conduct additional heat to depth, enhancing rates of permafrost thaw and thermokarst formation.

scholarly journals GEOMATICS TECHNOLOGIES IN THE FRAMEWORK OF MULTIDISCIPLINARY PROJECT FOR INTEGRATED MANAGEMENT OF CULTURAL HERITAGE SITES

2020 ◽  
Vol XLIII-B2-2020 ◽  
pp. 1477-1484
Author(s):  
C. Moise ◽  
A.-M. Lazar ◽  
C. E. Mihalache ◽  
L. A. Dedulescu ◽  
I. F. Dana Negula ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Cultural Heritage ◽  
Integrated Management ◽  
Heritage Sites ◽  
Non Invasive ◽  
Aerial Mapping ◽  
Remote Sensing Techniques ◽  
Complex Project ◽  
The Right ◽  
Photorealistic Models

Abstract. Cultural heritage represents the link between past and present civilizations, contributing to the right appreciation of the present-day by understanding the historical evolution of different human communities that are shaping our world. Preservation of the cultural heritage and mitigating potential risks on invaluable artifacts or objectives is key to conserving the identity of present and future generations. Our complex project is dedicated to monitoring, conservation, protection and promotion of the Romanian cultural heritage. It addresses the challenge of better safeguarding the cultural heritage by developing a multidisciplinary approach.The combined use of Synthetic Aperture Radar and multispectral satellite imagery represent a non-invasive investigation instrument that enable multitemporal analysis, contributing with valuable insights regarding cultural heritage sites. Remote sensing techniques were used to generate geospatial products such as displacement maps, urban sprawl evolution maps, urban heat island maps and many more.For protecting important artifacts, innovative recipes based on nanotechnologies were developed. In order to promote these artifacts, 3D photorealistic models were created using 3D reconstruction technology. For selected cultural heritage objectives, an integrated LiDAR aerial mapping system has enabled the creation of a high accuracy 3D model.This paper illustrates how different technologies, ranging from remote sensing to nanotechnology, could be used for safeguarding and promoting the Romanian cultural heritage and represents a first step in establishing and consolidating a multidisciplinary team involved in this domain.

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