784 research outputs found
Temporal continuos drone-based thermal infrared data
No full textThe data are raw data recorded during a drone flight. Yet, instead of flying the drone hovered over a predefined location (31.576516°, 35.415775°) recording the very same location for a period for 167 seconds at approximately 5Hz. Thus, the data consist of 670 single thermal infrared images recorded with a long-wave infrared camera core (FLIR Tau2), which is an uncooled VOx Microbolometer with a 19mm lens and a 640x512 focal plane array. The intention was to exploit spatiotemporal continuous thermal infrared data to outline and investigate submarine groundwater discharge and deduce possible discharge behavior. The here presented raw data are the basis for the study Mallast, U. and Siebert, C.: Combining continuous spatial and temporal scales for SGD investigations using UAV-based thermal infrared measurements, Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-361, in review, 2018
Localisation and temporal variability of groundwater discharge into the Dead Sea using thermal satellite data
No full textThe semi-arid region of the Dead Sea heavily relies on groundwater resources. This dependence is exacerbated by both population growth and agricultural activities and demands a sustainable groundwater management. Yet, information on groundwater discharge as one main component for a sustainable management varies significantly in this area. Moreover, discharge locations, volume and temporal variability are still only partly known. A multi-temporal thermal satellite approach is applied to localise and semi-quantitatively assess groundwater discharge along the entire coastline. The authors use 100 Landsat ETM + band 6.2 data, spanning the years between 2000 and 2011. In the first instance, raw data are transformed to sea surface temperature (SST). To account for groundwater intermittency and to provide a seasonally independent data set a dagger T (maximum SST range) per-pixel within biennial periods is calculated subsequently. Groundwater affected areas (GAA) are characterised by a dagger T < 8.5 A degrees C. Unaffected areas exhibit values > 10 A degrees C. This allows the exact identification of 37 discharge locations (clusters) along the entire Dead Sea coast, which spatially correspond to available in situ discharge observations. Tracking the GAA extents as a direct indicator of groundwater discharge volume over time reveals (1) a temporal variability correspondence between GAA extents and recharge amounts, (2) the reported rigid ratios of discharge volumes between different spring areas not to be valid for all years considering the total discharge, (3) a certain variability in discharge locations as a consequence of the Dead Sea level drop, and finally (4) the assumed flushing effect of old Dead Sea brines from the sedimentary body to have occurred at least during the two series of 2000-2001 and 2010-2011
Airborne Thermal Data Identifies Groundwater Discharge at the North-Western Coast of the Dead Sea
No full textA qualitative and quantitative monitoring of groundwater discharge was conducted based on an airborne thermal campaign undertaken along the north-western coast of the Dead Sea in January 2011 to contribute to the relatively scarce information on groundwater discharge to date in the region. The application of airborne thermal data exploits thermal contrasts that exist between discharging groundwater and background sea surface temperatures of the Dead Sea. Using these contrasts, 72 discharge sites were identified from which only 42 were known from previous in situ measurements undertaken at terrestrial springs by the Israel Hydrological Service. Six of these sites represent submarine springs and at a further 24 locations groundwater appears to seep through the sediment. Although the abundance of groundwater seepage sites suggests a significant, but so far unknown groundwater source, the main contribution appears to originate from terrestrial springs. In an attempt to provide a quantitative approach for terrestrial springs, a linear bootstrap regression model between in situ spring discharge and respective thermal discharge plumes (r2 = 0.87 p < 0.001) is developed and presented here. While the results appear promising and could potentially be applied to derive discharge values at unmonitored sites, several influence factors need to be clarified before a robust and reliable model to efficiently derive a complete quantitative picture of groundwater discharge can be proposed
ULF vlny/fluktuace ve forešoku: Statistický přístup
No full textTitle: ULF waves/fluctuations in the foreshock: Statistical approach Author: Anna Mita Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc., Department of Surface and Plasma Science Abstract: The thesis deals with ultra-low frequency (ULF) wave activity in the terrestrial foreshock, a turbulent region upstream of the bow shock that plays a crucial role in the interaction of the solar wind with the magnetosphere. In the thesis, we analyze some aspects of the behavior of ULF waves/fluctuations of the magnetic field, using a statistical point of view. We focused (i) on the boundary between the pure solar wind and wave activity region represented by enhanced ULF fluctuations, and on the changes of the boundary position with solar wind conditions and interplanetary magnetic field orientation; and (ii) on growth rates of foreshock ULF fluctuations at different distances from the bow shock with a special highlight on a region close to the Moon. In both statistical studies, we use THEMIS/ARTEMIS data and describe the behavior of fluctuations by the standard deviations in the ULF range of 0.0017-0.17 Hz. We present a novel coordinate system, determine so-called "foreshock ULF boundary" and report its realistic shape that is consistent with the theory of the foreshock...Název práce: ULF vlny/fluktuace ve forešoku: Statistický přístup Autor: Anna Mita Katedra: Katedra fyziky povrchů a plazmatu Vedoucí disertační práce: Prof. RNDr. Jana Šafránková, DrSc., Katedra fyziky povrchů a plazmatu Abstrakt: Předložená práce se zabývá ULF (Ultra Low Frequency) fluktuacemi v turbulentní oblasti před rázovou vlnou (forešok), která hraje klíčovou roli v interakci slunečního větru s magnetosférou Země. V práci analyzujeme některé aspekty chování ULF vln/fluktuací magnetického pole s využitím statistického zpracování dat naměřených dvěma družicemi projektu THEMIS/ARTEMIS. Zaměřili jsme se (i) na hranici mezi neporušeným slunečním větrem a oblastí charakterizovanou vysokými ULF fluktuacemi a na změny polohy této hranice v závislosti na podmínkách ve slunečním větru a na orientaci meziplanetárního magnetického pole; a (ii) na rychlost růstu nebo tlumení ULF vln/fluktuací v různých vzdálenostech od rázové vlny se zvláštním zřetelem na oblast blízko Měsíce. Ve statistických studiích popisujeme chování fluktuací pomocí směrodatných odchylek v rozsahu 0,0017-0,17 Hz. V práci představujeme nový souřadnicový systém umožňující určit tzv. "foreshock ULF boundary", diskutujeme nalezený tvar a ukazujeme, že je v souladu s teorií formování forešoku. Ve druhé studii se soustřeďujeme na růst (případně...Katedra fyziky povrchů a plazmatuDepartment of Surface and Plasma ScienceFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult
ULF waves/fluctuations in the foreshock: Statistical approach
No full textTitle: ULF waves/fluctuations in the foreshock: Statistical approach Author: Anna Mita Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Jana Šafránková, DrSc., Department of Surface and Plasma Science Abstract: The thesis deals with ultra-low frequency (ULF) wave activity in the terrestrial foreshock, a turbulent region upstream of the bow shock that plays a crucial role in the interaction of the solar wind with the magnetosphere. In the thesis, we analyze some aspects of the behavior of ULF waves/fluctuations of the magnetic field, using a statistical point of view. We focused (i) on the boundary between the pure solar wind and wave activity region represented by enhanced ULF fluctuations, and on the changes of the boundary position with solar wind conditions and interplanetary magnetic field orientation; and (ii) on growth rates of foreshock ULF fluctuations at different distances from the bow shock with a special highlight on a region close to the Moon. In both statistical studies, we use THEMIS/ARTEMIS data and describe the behavior of fluctuations by the standard deviations in the ULF range of 0.0017-0.17 Hz. We present a novel coordinate system, determine so-called "foreshock ULF boundary" and report its realistic shape that is consistent with the theory of the foreshock..
Dream on, but with your eyes open: An obituary for Ulf Kadritzke (1943-2020)
No full textUlf Kadritzke war der PROKLA als Autor und Mitglied des Redaktionsbeirats viele Jahre eng verbunden. Mit seinen Ideen und seinem Engagement hat er nicht nur die PROKLA bereichert und geprägt. Am 14. November 2020 verstarb Ulf Kadritzke überraschend.Ulf Kadritzke was closely associated with PROKLA for many years as an author and a member of the editorial advisory board. With his ideas and commitment, he enriched and shaped not only PROKLA. Ulf Kadritzke passed away unexpectedly on November 14, 2020
Ulf eta Cornelia: Berlingo maitasun istorio bat
No full text“Ulf and Cornelia: A Berlin love story” is part of the PhD thesis Berlin fin de millenium: An Experiment in Corporeal Ethnography, carried out between 1998 and 2003. In this article, the author puts into practice his investigative endeavor as a discovery process, narrating his encounters with Ulf and Cornelia, two bodies in transit in a Berlin characterized by its dramatic urban transformation. The focus of the ethnography is Ulf’s enamored experience. Using wonder as a knowledge technique, we will dive in the realm previous to the formation of stable identities, meaning the domain of corporeal stimulus and unconscious impulses. The subjects that appear in the scenes of this article, the author himself and the city where they live are in construction.“Ulf y Cornelia: una historia de amor berlinesa” es un apartado que pertenece a la tesis Berlín fin de milenio: un experimento en la etnografía corporal, realizada entre 1998 y 2003. En este artículo, el autor lleva a cabo una labor de investigación puesta en práctica como un proceso de descubrimientos, relatando sus encuentros con Ulf y Cornelia, dos cuerpos en tránsito en un Berlín sumido en una dramática transformación urbana. La etnografía está enfocada particularmente en la experiencia de enamoramiento de Ulf. Utilizando la capacidad de asombro como técnica para el conocimiento, nos sumergiremos en el ámbito anterior a la formación de identidades estables, es decir, en el dominio de estímulos corporales e impulsos inconscientes. Se trata, pues, de un artículo donde tanto los sujetos en escena como el propio autor y la ciudad en la que viven están en proceso de construcción.“Ulf eta Cornelia: maitasun istorio bat Berlinen”, 1999-2003 urteen artean garatutako Berlin fin de millenium: gorputz etnografíaren gaineko esperimentu bat tesiaren ataletako bat da. Artikulu honetan, autoreak, Ulfekin eta Corneliarekin, Berlin behin behineko bizilekutzat duten bi gorputzekin, bizitako uneak kontatzen dizkigu. Zehazki, Ulfen maitemintzea izango da etengabeko aurkikuntza prozesuan oinarritutako etnografía honen ardatza. Lilurarako gaitasuna ezagutzarako teknika bezala erabiliaz, nortasun egonkorrak eratu aurretiko eremura eramango gaitu, hau da, gorputz-estimulu eta bulkada inkontzienteen mundura. Azpimarratu behar da, artikulu honetan protagonista diren pertsonak, autorea bera eta bizi diren hiria eraikuntza prozesuan daudela
Current status and long-term insights into the western Dead Sea groundwater system using multi-sensoral remote sensing
No full textArid regions, that have a terrestrial share of 30 %, heavily rely on groundwater for do-mestic, industrial and irrigation purposes. The reliance on groundwater has partly turned into a dependency in areas where the increasing population number and the expansion of irrigated agricultural areas demand more groundwater than is naturally replenished. Yet, spatial and temporal information on groundwater are often scarce induced by the facts that groundwater is given a low priority in many national budgets and numerous (semi-) arid regions in the world encompass large and inaccessible areas. Hence, there is an urgent need to provide low-cost alternatives that in parallel cover large spatial and temporal scales to gain information on the groundwater system.
Remote sensing holds a tremendous potential to represent this alternative. The main objective of this thesis is the improvement of existing and the development of novel remote sensing applications to infer information on the scarce but indispensable resource groundwater at the example of the Dead Sea. The background of these de-velopments relies mainly on freely available satellite data sets. I investigate 1) the pos-sibility to infer potential groundwater flow-paths from digital elevation models, 2) the applicability of multi-temporal thermal satellite data to identify groundwater discharge locations, 3) the suitability of multi-temporal thermal satellite data to derive information on the long-term groundwater discharge behaviour, and 4) the differences of thermal data in terms of groundwater discharge between coarse-scaled satellite data and fine-scaled airborne data including a discharge quantification approach.
1) I develop a transparent, reproducible and objective semi-automatic approach us-ing a combined linear filtering and object based classification approach that bases on a medium resolution (30 m ground sampling distance) digital elevation model to extract lineaments. I demonstrate that the obtained lineaments have both, a hydrogeological and groundwater significance, that allow the derivation of potential groundwater flow-paths. These flow-paths match results of existing groundwater flow models remarkably well that validate the findings and shows the possibility to infer potential groundwater flow-paths from remote sensing data.
2) Thermal satellite data enable to identify groundwater discharge into open water bodies given a temperature contrast between groundwater and water body. Integrating a series of thermal data from different periods into a multi-temporal analysis accounts for the groundwater discharge intermittency and hence allows obtaining a representa-tive discharge picture. I analyse the constraints that arise with the multi-temporal anal-ysis (2000-2002) and show that ephemeral surface-runoff causes similar thermal anomalies as groundwater. To exclude surface-runoff influenced data I develop an au-tonomously operating method that facilitates the identification. I calculate on the re-maining surface-runoff uninfluenced data series different statistical measures on a per pixel basis to amplify groundwater discharge induced thermal anomalies. The results reveal that the range and standard deviation of the data series perform best in terms of anomaly amplification and spatial correspondence to in-situ determined spring dis-charge locations. I conclude on the reason that both mirror temperature variability that is stabilized and therefore smaller at areas where spatio-temporal constant groundwater discharge occurs.
3) The application of the before developed method on a thermal satellite data set spanning the years 2000 to 2011 enables to localise specific groundwater discharge sites and to semi-quantitatively analyse the temporal variability of the thermal anomalies (termed groundwater affected area - GAA). I identify 37 groundwater discharge sites along the entire Dead Sea coastline that refine the so far coarsely given spring areas to specific locations. All spatially match independent in-situ groundwater discharge observations and additionally indicate 15 so far unreported discharge sites. Comparing the variability of the GAA extents over time to recharge behaviour reveals analogous curve progressions with a time-shift of two years. This observation suggests that the thermally identified GAAs directly display the before only assumed groundwater discharge volume. This finding provides a serious alternative to monitor groundwater discharge over large temporal and spatial scales that is relevant for different scientific communities. From the results I furthermore conclude to observe the before only assumed and modelled groundwater discharge share from flushing of old brines during periods with an above average Dead Sea level drop. This observation implies the need to not only consider discharge from known terrestrial and submarine springs, but also from flushing of old-brines in order to calculate the total Dead Sea water budget.
4) I present a complementary airborne thermal data set recorded in 01/2011 over the north-western part of the Dead Sea coast. The higher spatial resolution allows to refine the satellite-based GAA to 72 specific groundwater discharge sites and even to specify the so far unknown abundance of submarine springs to six sites with a share of <10 % to the total groundwater discharge. A larger contribution stems from newly iden-tified seeping spring type (24 sites) where groundwater emerges diffusively either ter-restrial or submarine close to the land/water interface with a higher share to the total discharge than submarine springs provide. The major groundwater contribution origi-nates from the 42 identified terrestrial springs. For this spring type, I demonstrate that 93 % of the discharge volume can be modelled with a linear ordinary least square re-gression (R2=0.88) based on the thermal plume extents and in-situ measured discharge volumes from the Israel Hydrological Service. This result implies the possibility to determine discharge volumes at unmonitored sites along the Dead Sea coast as well that can provide a complete physically-based picture of groundwater discharge magni-tude to the Dead Sea for the first time.:1 Introduction
1.1 Remote sensing applications on groundwater
1.1.1 Classical aspects
1.1.2 Modern aspects
1.2 Motivation and main objectives
1.3 Why the western catchment of the Dead Sea?
1.4 Overview
2 The western catchment of the Dead Sea
2.1 Geological and Structural Overview
2.2 Groundwater system
2.3 Groundwater inputs
2.4 Dead Sea
3 Groundwater flow-paths
3.1 Prologue
4 Method development for groundwater discharge identification
4.1 Prologue
5 Localisation and temporal variability of groundwater discharge
5.1 Prologue
6 Qualitative and quantitative refinement of groundwater discharge
6.1 Prologue
7 Conclusion and Outlook
7.1 Main results and implications
7.2 Outlook
References
Appendi
Simulation of Bounce Resonance ULF Wave-Particle Interactions
No full textPoloidal mode ultra-low-frequency (ULF) waves with high azimuthal mode number (high-m) are common throughout Earth's magnetosphere. The electric fields in these waves are on the order of tens of millivolts per meter, and are large enough to energize ions and electrons via drift- and drift-bounce wave-particle resonance. In this article, we present full orbit test-particle simulations of drift-bounce resonance using a numerical model of ULF waves. The model uses a dipole magnetic field and can accommodate a realistic ionosphere with height-resolved Pedersen and Hall conductivity. It is demonstrated that second-harmonic poloidal mode waves can energize ions to tens of keV depending on the wave amplitude. The test-particle simulations also predict ion flux oscillations that have energy dispersion similar to many satellite observations. It will be shown that features in the energy dispersion are in agreement with theoretical considerations.CPCI-S(ISTP)[email protected]; [email protected]
THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events
No full textSudden impulses (SIs) are an important source of ultra low frequency (ULF) wave activity throughout the Earth's magnetosphere. Most SI-induced ULF wave events have been reported in the dayside magnetosphere; it is not clear when and how SIs drive ULF wave activity in the nightside plasma sheet. We examined the ULF response of the nightside plasma sheet to SIs using an ensemble of 13 SI events observed by THEMIS (Timed History of Events and Macroscale Interactions during Substorms) satellites (probes). Only three of these events resulted in ULF wave activity. The periods of the waves are found to be 3.3, 6.0, and 7.6 min. East-west magnetic and radial electric field perturbations, which typically indicate the toroidal mode, are found to be stronger and can have phase relationships consistent with standing waves. Our results suggest that the two largest-amplitude ULF responses to SIs in the nightside plasma sheet are tailward-moving vortices, which have previously been reported, and the dynamic response of cross-tail currents in the magnetotail to maintain force balance with the solar wind, which has not previously been reported as a ULF wave driver. Both mechanisms could potentially drive standing Alfven waves (toroidal modes) observed via the field-line resonance mechanism. Furthermore, both involve frequency selection and a preference for certain driving conditions that can explain the small number of ULF wave events associated with SIs in the nightside plasma sheet. Citation: Shi, Q. Q., et al. (2013), THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events, J. Geophys. Res. Space Physics, 118, 284-298, doi:10.1029/2012JA017984.Astronomy & AstrophysicsSCI(E)10ARTICLE1284-29811
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