FESSTVaL: Field Experiment on sub-mesoscale spatio-temporal variability in Lindenberg – the campaign 2021 an its predecessors

Measuring submesoscale variability is the core task of the field campaign FESSTVaL (Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg).&#160; FESSTVaL focuses on three sources of submesoscale variability: cold pools, wind gusts and boundary layer pattern. It took place in the summer months of 2021 at the Meteorological Observatory Lindenberg &#8211; Richard-A&#223;mann-Observatory (MOL-RAO) of the German Weather Service (DWD) near Berlin and was initiated by the Hans-Ertel-Center for Weather Research (HErZ).In order to capture phenomena at the submesoscale (500 m &#8211; 5 km), generally not captured by conventional measurement network, a hierarchical measurement strategy is adopted. This includes wind profiling stations with a coordinated scanning strategy of several Doppler Lidars, two mobile profilers to measure thermodynamic properties and precipitation, more than 100 stations with near-surface measurements of air temperature, pressure and soil moisture, more than 20 automatic weather stations, an X-Band radar, and a number of energy balance stations. This equipment is augmented by the extensive ground-based remote sensing array at the MOL-RAO, operated by DWD and by flights operated by Unmanned Aerial Systems. Complementing to this, the benefit of a citizen-science measurement network is investigated during the campaign with &#8220;Internet-of-things&#8221; based technology and low-cost sensors built and maintained by citizens. The measurements are supplemented by high-resolution large-eddy simulations (ICON-LES).Originally planned for the summer 2020, FESSTVaL had to be postponed to 2021 and replaced by three local individual campaigns, conducted in Bayern, Lindenberg and Hamburg in 2020. Those three test campaigns demonstrated the ability of the envisionned measurement strategy and planned instruments to capture submesoscale variability and submesoscale weather phenomean. This talk will give a brief overview on the results of these three campaigns, as a foretaste to FESSTVaL, together with some of the very first measurements taken during FESSTVaL.

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Sub-mesoscale observations of cold pools during FESSTVaL

10.5194/egusphere-egu2020-9779 ◽

2020 ◽

Author(s):

Bastian Kirsch ◽

Felix Ament ◽

Cathy Hohenegger ◽

Daniel Klocke

Keyword(s):

Low Cost ◽

Cold Pool ◽

Density Currents ◽

Horizontal Structure ◽

Cold Pools ◽

Meteorological Observatory ◽

First Results ◽

Spatio Temporal ◽

Operational Networks ◽

Measurement Strategies

Cold pools are areas of cool downdraft air that form through evaporation underneath precipitating clouds and spread on the surface as density currents. Their importance for the development and maintenance of convection is long known. Modern Large-Eddy simulations with a grid spacing of 1 km or less are able to explicitly resolve cold pools, however, they lack reference data for an adequate validation. Available point measurements from operational networks are too coarse and, therefore, miss the horizontal structure and dynamics of cold pools.The upcoming measurement campaign FESSTVaL (Field Experiment on Sub-mesocale Spatio-Temporal Variability in Lindenberg) aims to test novel measurement strategies for the observation of previously unresolved sub-mesoscale boundary layer structures and phenomena, such as cold pools. The key component of the experiment during this summer will be a dense network of ground-based measurements within 15 km around the Meteorological Observatory Lindenberg near Berlin. The network of 100 low-cost APOLLO (Autonomous cold POoL LOgger) stations allows to record air pressure and temperature with a spatial and temporal resolution of 100 m and 1 s, respectively. We present first results from a test campaign during last summer that successfully demonstrated the ability of the proposed network stations to observe cold pool dynamics on the sub-mesoscale.

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FESSTVaL: Field Experiment on sub-mesoscale spatio-temporal variability in Lindenberg – Übersicht der Messkampagne und erste Ergebnisse

10.5194/dach2022-237 ◽

2021 ◽

Author(s):

Kristina Lundgren ◽

Felix Ament ◽

Cathy Hohenegger ◽

Frank Beyrich ◽

Ulrich Löhnert ◽

...

Keyword(s):

Field Experiment ◽

Data Center ◽

Temporal Variability ◽

Doppler Lidar ◽

Climate Data ◽

Cold Pools ◽

X Band ◽

Large Eddy ◽

Erste Ergebnisse ◽

Spatio Temporal

Die FESSTVaL-Messkampagne (Field Experiment on sub-mesoscale spatio-temporal variability in Lindenberg) wurde im Sommer 2021 als eine gro&#223;e Kooperation mit gut zwei Dutzend Forschenden in der Umgebung des Meteorologischen Observatoriums Lindenberg des Deutschen Wetterdienstes durchgef&#252;hrt. Im Rahmen des Projektes stehen sommerliche Wetterereignisse im Fokus, um die Entstehung von &#8222;Cold Pools&#8220; und Windb&#246;en in der konvektiven Grenzschicht sowie deren Wechselwirkung besser zu verstehen. Aufgrund der kleinskaligen Natur dieser Wetterph&#228;nomene, k&#246;nnen sie nur bedingt von konventionellen Bodenmessungen erfasst werden, k&#246;nnen aber nichts-desto-trotz gro&#223;en Schaden anrichten. Einzigartig f&#252;r diese Kampagne ist daher die hohe Dichte der durchgef&#252;hrten Bodenmessungen mit &#252;ber 100 bodennahen Messungen hinsichtlich Temperatur und Druck und 20 automatischen Wetterstationen sowie ein dichtes Bodenfeuchtemessnetz. Ein X-Band Radar und mehrere Energiebilanzstationen wurden ebenfalls eingesetzt. Des Weiteren wurden in Kooperation mit externen Partnern am KIT und DLR neun Doppler-Lidar-Systeme f&#252;r Messungen des Windprofils und von Turbulenzvariablen bis in mehrere Kilometer H&#246;he koordiniert getestet. Durch ein Messnetz von vier Mikrowellenradiometern und weiteren &#8222;Profilern&#8220; wurden thermodynamische Eigenschaften der Grenzschicht sowie von Wolken und Niederschlag gemessen. Zus&#228;tzlich dazu wurden Messfl&#252;ge mit unbemannten und ferngesteuerten Flugzeugen durch die Universit&#228;t T&#252;bingen und das DLR durchgef&#252;hrt, um weitere Informationen in der Vertikalen zu erzielen und um die bodengebundene Fernerkundungssysteme zu evaluieren. Als Erg&#228;nzung zu diesen Messungen wird im Rahmen des Projektes der Informationsgewinn durch ein Citizen Science Messnetzes untersucht. Die Messungen werden au&#223;erdem durch hoch-aufgel&#246;ste large-eddy Simulationen (ICON-LES) erg&#228;nzt. Die Ergebnisse des Projektes sollen unter anderem dazu dienen, die Darstellung solcher kleinskaligen Prozesse in der numerischen Wettervorhersage zu verbessern und neue Messstrategien zu definieren. Die Datenprodukte der Kampagne werden unter dem FAIR-Prinzip behandelt und werden &#252;ber einer Plattform am Integrated Climate Data Center der Universit&#228;t Hamburg zur Verf&#252;gung gestellt. Dieser Beitrag wird die Messstrategie von FESSTVaL n&#228;her beleuchten, erste Erkenntnisse und Ergebnisse zusammenfassen sowie einen Einblick in die Datenverf&#252;gbarkeit und deren Verwertungsperspektive geben.

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Untersuchungen zur Ableitung von Windböen aus Doppler-Lidar-Messungen

10.5194/dach2022-48 ◽

2021 ◽

Author(s):

Carola Detring ◽

Eileen Päschke ◽

Julian Steinheuer ◽

Ronny Leinweber ◽

Markus Kayser ◽

...

Keyword(s):

Field Experiment ◽

Temporal Variability ◽

Surface Wind ◽

Doppler Lidar ◽

Signal To Noise ◽

Observation Volume ◽

Wind Gusts ◽

Die Profile ◽

Spatio Temporal

Mit Hilfe von Doppler-Lidar-Systemen, lassen sich die Profile von Windgeschwindigkeit und -richtung in der Atmosph&#228;rischen Grenzschicht (AGS) auf der Basis klassischer Messstrategien wie einem VAD-24 Scan (Velocity Azimuth Display mit 24 Strahlrichtungen) zuverl&#228;ssig bestimmen (P&#228;schke et al., 2015). F&#252;r praktische Anwendungen von gro&#223;em Interesse sind jedoch neben dem mittleren Windprofil auch kurzzeitige Fluktuationen des Windes, wie sie zum Beispiel in Verbindung mit Windb&#246;en auftreten. Untersuchungen zu Windb&#246;en waren ein wesentlicher Aspekt der Messkampagne FESSTVaL (Field Experiment on Sub-Mesoscale Spatio-Temporal Variability in Lindenberg, www.fesstval.de).Eine Studie von Suomi et al. (2017) hat gezeigt, dass eine Ableitung von Windb&#246;en aus Doppler Lidar Messungen prinzipiell m&#246;glich ist. Allerdings wird mit &#252;blichen Messstrategien die hierf&#252;r erforderliche hohe zeitliche Aufl&#246;sung in der Ermittlung des Windvektors nicht erreicht, so dass mit Skalierungsans&#228;tzen unter Verwendung von in-situ Windmessungen eine Korrektur der aus den Lidar-Daten abgeleiteten B&#246;enwerte erfolgen muss.Im Rahmen der vorliegenden Arbeit wurde eine alternative Messstrategie f&#252;r Doppler-Lidar-Systeme vom Typ &#8222;Streamline&#8220; (Halo Photonics) entwickelt und &#252;ber mehrere Monate in den Jahren 2020/21 auf dem Grenzschichtmessfeld Falkenberg des DWD erprobt. Die B&#246;enableitung basiert auf einem sog. Continous Scan Mode (CSM); dabei werden die w&#228;hrend einer vollst&#228;ndigen Rotation des Lidar-Scan-Kopfes kontinuierlich durchgef&#252;hrten Messungen 10-11 Strahlrichtungen zugeordnet und die Radialwindgeschwindigkeiten wiederum mit dem VAD-Verfahren ermittelt. Die Dauer eines Scans betr&#228;gt etwa 3.4s, damit kann eine Zeitaufl&#246;sung erreicht werden, die der heute weit verbreiteten Definition einer Windb&#246; entspricht (3s gleitendes Mittel; WMO (2018)).Diese neue Konfiguration bringt Herausforderungen an die Datenverarbeitung mit sich. Im CSM muss mit vergleichsweise wenigen Lidar-Pulsen pro Messstrahl gearbeitet werden, so dass klassische Ans&#228;tze der Datenfilterung (Signal-to-Noise Schwellwert, Consensus Filterung) nicht verwendet werden k&#246;nnen. Es wird ein alternatives Verfahren f&#252;r die Prozessierung der Lidar-Rohdaten vorgeschlagen. Die Ergebnisse der Ableitung sowohl des mittleren Windvektors als auch der jeweiligen maximalen Windb&#246; in einem 10-Minuten-Mittelungsintervall werden mit Sonic-Messungen in 90m H&#246;he verglichen.&#160;Im Rahmen des FESSTVaL Experimentes wurde diese neue Messkonfiguration an drei Standorten, die ein ann&#228;hernd gleichseitiges Dreieck mit einer Kantenl&#228;nge von etwa 5 km bildeten, genutzt. Es werden Fallbeispiele aus der FESSTVaL Kampagne f&#252;r die Variabilit&#228;t im Auftreten von Windb&#246;en gezeigt.ReferenzenP&#228;schke, E., Leinweber, R., and Lehmann, V. (2015): An assessment of the performance of a 1.5 &#956;m Doppler lidar for operational vertical wind profiling based on a 1-year trial, Atmos. Meas. Tech., 8, 2251&#8211;2266, https://doi.org/10.5194/amt-8-2251-2015Suomi, I., Gryning, S.&#8208;E., O'Connor, E.J. and Vihma, T. (2017): Methodology for obtaining wind gusts using Doppler lidar. Q.J.R. Meteorol. Soc., 143: 2061-2072. https://doi.org/10.1002/qj.3059World Meteorological Organization (WMO) (2018): Measurement of surface wind. In Guide to Meteorological Instruments and Methods of Observation, Volume I -Measurement of Meteorological Variables, No.8: 196&#8211;213, URL: https://library.wmo.int/doc_num.php?explnum_id=10616 (accessed November 2021)

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Assessment of Low-Cost Unmanned Aerial Systems for Engineering Surveys

Lecture Notes in Civil Engineering - Proceedings of UASG 2019 ◽

10.1007/978-3-030-37393-1_2 ◽

2020 ◽

pp. 11-18

Author(s):

Amit Rana ◽

Inshu Chauhan ◽

Gaurav Bhatt

Keyword(s):

Low Cost ◽

Unmanned Aerial Systems ◽

Aerial Systems

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Accuracy of 3D Landscape Reconstruction without Ground Control Points Using Different UAS Platforms

Drones ◽

10.3390/drones4020013 ◽

2020 ◽

Vol 4 (2) ◽

pp. 13 ◽

Cited By ~ 4

Author(s):

Margaret Kalacska ◽

Oliver Lucanus ◽

J. Pablo Arroyo-Mora ◽

Étienne Laliberté ◽

Kathryn Elmer ◽

...

Keyword(s):

Low Cost ◽

Ground Control ◽

Unmanned Aerial Systems ◽

Control Points ◽

Model Errors ◽

Positional Accuracy ◽

Ground Control Points ◽

Digital Elevation ◽

High Level ◽

Aerial Systems

The rapid increase of low-cost consumer-grade to enterprise-level unmanned aerial systems (UASs) has resulted in the exponential use of these systems in many applications. Structure from motion with multiview stereo (SfM-MVS) photogrammetry is now the baseline for the development of orthoimages and 3D surfaces (e.g., digital elevation models). The horizontal and vertical positional accuracies (x, y and z) of these products in general, rely heavily on the use of ground control points (GCPs). However, for many applications, the use of GCPs is not possible. Here we tested 14 UASs to assess the positional and within-model accuracy of SfM-MVS reconstructions of low-relief landscapes without GCPs ranging from consumer to enterprise-grade vertical takeoff and landing (VTOL) platforms. We found that high positional accuracy is not necessarily related to the platform cost or grade, rather the most important aspect is the use of post-processing kinetic (PPK) or real-time kinetic (RTK) solutions for geotagging the photographs. SfM-MVS products generated from UAS with onboard geotagging, regardless of grade, results in greater positional accuracies and lower within-model errors. We conclude that where repeatability and adherence to a high level of accuracy are needed, only RTK and PPK systems should be used without GCPs.

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A Framework for Multiple Ground Target Finding and Inspection Using a Multirotor UAS

Sensors ◽

10.3390/s20010272 ◽

2020 ◽

Vol 20 (1) ◽

pp. 272 ◽

Cited By ~ 2

Author(s):

Ajmal Hinas ◽

Roshan Ragel ◽

Jonathan Roberts ◽

Felipe Gonzalez

Keyword(s):

Target Detection ◽

Low Cost ◽

Target Position ◽

Position Estimation ◽

Quality Data ◽

Unmanned Aerial Systems ◽

Modular Software ◽

Ground Target ◽

High Level ◽

Aerial Systems

Small unmanned aerial systems (UASs) now have advanced waypoint-based navigation capabilities, which enable them to collect surveillance, wildlife ecology and air quality data in new ways. The ability to remotely sense and find a set of targets and descend and hover close to each target for an action is desirable in many applications, including inspection, search and rescue and spot spraying in agriculture. This paper proposes a robust framework for vision-based ground target finding and action using the high-level decision-making approach of Observe, Orient, Decide and Act (OODA). The proposed framework was implemented as a modular software system using the robotic operating system (ROS). The framework can be effectively deployed in different applications where single or multiple target detection and action is needed. The accuracy and precision of camera-based target position estimation from a low-cost UAS is not adequate for the task due to errors and uncertainties in low-cost sensors, sensor drift and target detection errors. External disturbances such as wind also pose further challenges. The implemented framework was tested using two different test cases. Overall, the results show that the proposed framework is robust to localization and target detection errors and able to perform the task.

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Assessing the Accuracy of Digital Surface Models Derived from Optical Imagery Acquired with Unmanned Aerial Systems

Drones ◽

10.3390/drones3010015 ◽

2019 ◽

Vol 3 (1) ◽

pp. 15 ◽

Cited By ~ 18

Author(s):

Salvatore Manfreda ◽

Petr Dvorak ◽

Jana Mullerova ◽

Sorin Herban ◽

Pietro Vuono ◽

...

Keyword(s):

3D Model ◽

Low Cost ◽

Three Dimensional ◽

Careful Consideration ◽

Ground Control ◽

Unmanned Aerial Systems ◽

Control Points ◽

Earthen Dam ◽

Ground Control Points ◽

Aerial Systems

Small unmanned aerial systems (UASs) equipped with an optical camera are a cost-effective strategy for topographic surveys. These low-cost UASs can provide useful information for three-dimensional (3D) reconstruction even if they are equipped with a low-quality navigation system. To ensure the production of high-quality topographic models, careful consideration of the flight mode and proper distribution of ground control points are required. To this end, a commercial UAS was adopted to monitor a small earthen dam using different combinations of flight configurations and by adopting a variable number of ground control points (GCPs). The results highlight that optimization of both the choice and combination of flight plans can reduce the relative error of the 3D model to within two meters without the need to include GCPs. However, the use of GCPs greatly improved the quality of the topographic survey, reducing error to the order of a few centimeters. The combined use of images extracted from two flights, one with a camera mounted at nadir and the second with a 20° angle, was found to be beneficial for increasing the overall accuracy of the 3D model and especially the vertical precision.

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Detection of Conflicts Between ADS-B-Equipped Aircraft and Unmanned Aerial Systems

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198119900645 ◽

2020 ◽

Vol 2674 (1) ◽

pp. 197-204

Author(s):

John H. Mott ◽

Zachary A. Marshall ◽

Mark A. Vandehey ◽

Mike May ◽

Darcy M. Bullock

Keyword(s):

High Performance ◽

Low Cost ◽

Federal Aviation Administration ◽

Unmanned Aircraft ◽

Sensor Technology ◽

Unmanned Aerial Systems ◽

Aircraft Flight ◽

Flight Operations ◽

Aerial Systems ◽

Operational Simplicity

Versatile unmanned aerial system (UAS) platforms have grown significantly in popularity by virtue of their low cost relative to manned aircraft, high performance, and operational simplicity. While the Federal Aviation Administration (FAA) currently regulates the operating altitudes, speeds, weights, pilot qualifications, and locations of drones, a lack of capacity and technology prohibits sufficient enforcement of these restrictions. To assess the frequency and severity of manned and unmanned aircraft separation incidents, and to examine the emerging sensor technology available to facilitate such assessment, flight operations in controlled airspace around Orlando Melbourne International Airport (KMLB) were monitored. One sensor system deployed at KMLB reported UAS locations, altitudes, and flight durations, while a second system reported manned aircraft positions, altitudes, and timestamps using ADS-B signals. Evaluation of flight operations data in the vicinity of KMLB revealed eight potential drone incursions over a 2-week period. Aircraft flight paths were retroactively tracked to map these unmanned and manned aerial conflicts; aircraft identification information was also researched to contextualize the incidents. The frequency and magnitude of identified events suggest the need for additional research to further explore the problem scope and potential solutions.

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