Multiscale Variability and the Comparison of Ground and Satellite Radar Based Measures of Peatland Surface Motion for Peatland Monitoring

Peatland surface motion is highly diagnostic of peatland condition. Interferometric Synthetic Aperture Radar (InSAR) can measure this at the landscape scale but requires ground validation. This necessitates upscaling from point to areal measures (80 × 90 m) but is hampered by a lack of data regarding the spatial variability of peat surface motion characteristics. Using a nested precise leveling approach within two areas of upland and low-lying blanket peatland within the Flow Country, Scotland, we examine the multiscale variability of peat surface motion. We then compare this with InSAR timeseries data. We find that peat surface motion varies at multiple scales within blanket peatland with decreasing dynamism with height above the water table e.g., hummocks < lawn < hollows. This trend is dependent upon a number of factors including ecohydrology, pool size/density, peat density, and slope. At the site scale motion can be grouped into central, marginal, and upland peatlands with each showing characteristic amplitude, peak timing, and response to climate events. Ground measurements which incorporate local variability show good comparability with satellite radar derived timeseries. However, current limitations of phase unwrapping in interferometry means that during an extreme drought/event InSAR readings can only qualitatively replicate peat movement in the most dynamic parts of the peatland e.g., pool systems, quaking bog.

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Drought: The Silent Harm of Migration From Central America During the Period 1990 to 2019

10.20944/preprints202106.0612.v1 ◽

2021 ◽

Author(s):

Sazcha Olivera ◽

María del Pilar Fuerte-Celis ◽

Bernardo Bolaños

Keyword(s):

Central America ◽

Human Mobility ◽

Stochastic Frontier ◽

Drought Event ◽

Stochastic Frontier Model ◽

Climate Factors ◽

Place Of Origin ◽

Climate Events ◽

The Relationship ◽

Rain Precipitation

The worldwide number of migrants has had a rapid increase during the last fifteen years. Despite the extensive research studies that elucidate the increase in migrants' recipient countries, we know little about the relationship between the climate factors and human mobility in the countries of origin. Hence, this study focuses on the effects of weather and the propensity of individuals to leave a territory by measuring the importance of rain precipitation or the lack of it in one of the critical food corridors of Central America, formed by El Salvador, Honduras, and Guatemala. To study the mobility process, we develop a stochastic frontier model; the main result shows a greater propensity to migrate when there is a significant drought event in the place of origin. Some other factors that motivate people to leave their homeland are the effect of other climate events measured through the control system (ENSO), homicide levels, economic performance, and exchange rate. The findings allow differentiating between drought and excess precipitation on a population and mobility to other territories. In addition, these results permit us to derive observable implications of the different effects of flooding and drought and create public policies of prevention, mitigation, and resilience.

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On the surface motion characteristics in a single layered half-space excited by bulk waves

Acta Mechanica ◽

10.1007/s00707-017-1868-6 ◽

2017 ◽

Vol 228 (9) ◽

pp. 3329-3344 ◽

Cited By ~ 1

Author(s):

Pankaj Kumar ◽

Anirvan DasGupta ◽

Ranjan Bhattacharyya

Keyword(s):

Half Space ◽

Surface Motion ◽

Bulk Waves ◽

Motion Characteristics ◽

Layered Half Space

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Comparison of Full-Scale Measurements With Calculated Motion Characteristics of a West of Africa FPSO

Volume 1: Offshore Technology; Ocean Space Utilization ◽

10.1115/omae2003-37182 ◽

2003 ◽

Author(s):

Radboud R. T. van Dijk ◽

Vale´rie Quiniou-Ramus ◽

Guillaume Le-Marechal

Keyword(s):

Loading Condition ◽

Transfer Functions ◽

Diffraction Theory ◽

Full Scale ◽

Test Results ◽

Wave Direction ◽

Roll Damping ◽

Motion Characteristics ◽

One Year ◽

Scale Motion

Full-scale measurements of the motions of the Girassol FPSO are available over a one-year period. During this same period also vessel draft, wave height and wave direction have been recorded. This allows the calculation of motion transfer functions as function of the FPSO loading condition. A comparison has been made between the measured motion transfer functions and the calculated motion transfer functions based on diffraction theory, taking into account the measured wave spreading. Viscous roll damping has been added in the calculation to obtain maximum agreement between measured and calculated RAO’s. The results show that wave spreading is a very important factor on how the vessel behaves and should be taken into account when evaluating measured full-scale motion RAO’s. This paper addresses the full-scale monitoring campaign in some detail and the related issues. Furthermore it describes the technique how measured wave spreading is taken into account in the calculation of theoretical motion RAO’s. It is shown that the agreement between calculated and measured RAO’s is greatly improved by the use of measured wave spreading in the calculation. The levels of viscous roll damping found in this tuning process can be described as function of loading condition and sea state. The viscous roll damping found in this process also shows good agreement to model test results performed earlier on this same FPSO.

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Use of Surface Motion Characteristics Determined by InSAR to Assess Peatland Condition

Journal of Geophysical Research Biogeosciences ◽

10.1029/2018jg004953 ◽

2020 ◽

Vol 125 (1) ◽

Cited By ~ 2

Author(s):

Lubna Alshammari ◽

Doreen S. Boyd ◽

Andrew Sowter ◽

Chris Marshall ◽

Roxane Andersen ◽

...

Keyword(s):

Surface Motion ◽

Motion Characteristics

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Identification of typical eco-hydrological behaviours using InSAR allows landscape-scale mapping of peatland condition

10.5194/esurf-2021-58 ◽

2021 ◽

Author(s):

Andrew Vincent Bradley ◽

Roxane Andersen ◽

Chris Marshall ◽

Andrew Sowter ◽

David James Large

Keyword(s):

Bimodal Distribution ◽

Global Scale ◽

Landscape Scale ◽

Gas Content ◽

Surface Motion ◽

Vegetation Communities ◽

Peatland Restoration ◽

Blanket Bog ◽

Satellite Radar ◽

Topographic Gradients

Abstract. Better tools for rapid and reliable assessment of global peatland extent and condition are urgently needed to support action to prevent their further decline. Peatland surface motion is a response to changes in the water and gas content of a peat body regulated by the ecology and hydrology of a peatland system. Surface motion is therefore a sensitive measure of ecohydrological condition but has traditionally been impossible to measure at the landscape scale. Here we examine the potential of surface motion metrics derived from InSAR satellite radar to map peatland condition in a blanket bog landscape. We show that the timing of maximum seasonal swelling of the peat is characterized by a bimodal distribution. The first maximum is typical of steeper topographic gradients, peatland margins, degraded peatland and more often associated with ‘shrub’-dominated vegetation communities. The second maximum is typically associated with low topographic gradients often featuring pool systems, and Sphagnum dominated vegetation communities. Specific conditions associated with ‘Sphagnum’ and ‘shrub’ communities are also determined by the amplitude of swelling and average multiannual motion. Peatland restoration currently follows a re-wetting strategy, however our approach highlights that landscape setting appears to determine the optimal endpoint for restoration. Aligning expectation for restoration outcomes with landscape setting might optimise peatland stability and carbon storage. Importantly, deployment of this approach, based on surface motion dynamics, could support peatland mapping and management on a global scale.

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Determining regional scale carbon losses from tropical peatlands using ISBAS-InSAR

10.5194/egusphere-egu2020-4715 ◽

2020 ◽

Author(s):

Martha Ledger ◽

Sofie Sjögersten ◽

Andrew Sowter ◽

David Large ◽

Chris Evans ◽

...

Keyword(s):

Forest Canopy ◽

Surface Deformation ◽

Regional Scale ◽

Surface Motion ◽

Tropical Peatland ◽

Se Asia ◽

Tropical Peatlands ◽

Peat Surface ◽

Carbon Losses ◽

The Impact

80% of peatlands in Indonesia and Malaysia (15% of Earth's soil carbon) are now drained for production of pulp wood and palm oil. Associated increased peat decomposition and large-scale forest fires are now significant contributors to global greenhouse gas emissions. However, carbon losses from these processes and the impact of peatland drainage remain poorly quantified across SE Asia because of the challenging scale and inaccessibility of dense tropical peatland forests.Space-based platforms offer the opportunity for regular and efficient pan-regional monitoring and overcome inaccessibility of tropical peatland environments. A development in satellite&#160;interferometric synthetic aperture radar (InSAR) in monitoring surface motion has the potential to solve this problem. A new &#8216;intermittent small baseline subset&#8217;&#160;(ISBAS) modelling technique provides excellent coverage across almost all land surfaces irrespective of ground cover, enabling long-term measurement of peatland surface motion across whole catchments, regions and countries. Importantly, the ISBAS technique is able to determine surface deformation under tropical forest canopy using C-band&#160;InSAR, enabling continuous&#160;monitoring of surface motion ranging from 0.1&#8211;40cm/yr&#160;at spatial scales&#160;&#8805;90x90m.This project aims to determine whether rate of subsidence of the peat surface measured by&#160;ISBAS-InSAR&#160;is a proxy for rate of carbon loss in&#160;tropical peatlands in SE Asia. ISBAS-InSAR&#160;time series and field measurements of subsidence&#160;will be used to monitor and characterise seasonal tropical peat surface oscillations over time and field radar experiments will investigate C-band radar signal attenuation with the peat surface at different moisture contents.

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Large-scale Motion of Solar Filaments

International Astronomical Union Colloquium ◽

10.1017/s0252921100064502 ◽

2000 ◽

Vol 179 ◽

pp. 205-208

Author(s):

Pavel Ambrož ◽

Alfred Schroll

Keyword(s):

Magnetic Flux ◽

Proper Motion ◽

Time Scale ◽

Large Scale ◽

Accuracy Of Measurements ◽

Solar Filaments ◽

General Movement ◽

Scale Motion ◽

Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

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The IBM-PC in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165525 ◽

1996 ◽

Vol 54 ◽

pp. 612-613

Author(s):

James F. Mancuso

Keyword(s):

Head Start ◽

Image Acquisition ◽

Cost Effective ◽

Financial Applications ◽

Number Of Factors ◽

Instrument Control ◽

The Cost ◽

Training And Support ◽

Control Image ◽

Ibm Pc

IBM PC compatible computers are widely used in microscopy for applications ranging from control to image acquisition and analysis. The choice of IBM-PC based systems over competing computer platforms can be based on technical merit alone or on a number of factors relating to economics, availability of peripherals, management dictum, or simple personal preference.IBM-PC got a strong “head start” by first dominating clerical, document processing and financial applications. The use of these computers spilled into the laboratory where the DOS based IBM-PC replaced mini-computers. Compared to minicomputer, the PC provided a more for cost-effective platform for applications in numerical analysis, engineering and design, instrument control, image acquisition and image processing. In addition, the sitewide use of a common PC platform could reduce the cost of training and support services relative to cases where many different computer platforms were used. This could be especially true for the microscopists who must use computers in both the laboratory and the office.

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