scholarly journals Toward an open-access of high-frequency lake modelling and statistics data for scientists and practitioners. The case of Swiss Lakes using Simstrat v2.1

2019 ◽  
Author(s):  
Adrien Gaudard ◽  
Love Råman Vinnå ◽  
Fabian Bärenbold ◽  
Martin Schmid ◽  
Damien Bouffard
Keyword(s):  
Open Access ◽  
High Frequency ◽  
Thermal Structure ◽  
Regional Scale ◽  
Easy Access ◽  
Strong Wind ◽  
Long Term Effects ◽  
Output Data ◽  
Data Platform ◽  
Wind Events

Abstract. One-dimensional hydrodynamic lake models are nowadays widely recognized as key tools. They offer the possibility to study processes at high frequency, here referring to hourly time scale, to analyse scenarios and test hypothesizes. Yet, simulation outputs are mainly used by the modellers themselves and often not easily reachable for the outside community. We have developed an openly accessible web-based platform for visualization and promotion of easy access to lake model output data updated in near real time (https://simstrat.eawag.ch/). This platform was developed for 54 lakes in Switzerland with potential for adaptation to other regional areas or even at global worldwide scale using appropriate forcing input data. The benefit of this data platform is here practically illustrated with two examples. First we show that the output data allows for assessing the long term effects of past climate change on the thermal structure of a lake. In the second case, we demonstrate how the data platform can be used to study and compare the role of episodic strong wind events for different lakes on a regional scale and especially how they temporary destabilize their thermal structure. With this open access data platform we demonstrate the path forward for scientists and practitioners promoting a cross-exchange of expertise through openly sharing of in-situ and model data.

scholarly journals Toward an open access to high-frequency lake modeling and statistics data for scientists and practitioners – the case of Swiss lakes using Simstrat v2.1

2019 ◽  
Vol 12 (9) ◽  
pp. 3955-3974 ◽  
Author(s):  
Adrien Gaudard ◽  
Love Råman Vinnå ◽  
Fabian Bärenbold ◽  
Martin Schmid ◽  
Damien Bouffard
Keyword(s):  
Open Access ◽  
High Frequency ◽  
Thermal Structure ◽  
Regional Scale ◽  
Easy Access ◽  
Strong Wind ◽  
Long Term Effects ◽  
Output Data ◽  
Data Platform ◽  
Wind Events

Abstract. One-dimensional hydrodynamic models are nowadays widely recognized as key tools for lake studies. They offer the possibility to analyze processes at high frequency, here referring to hourly timescales, to investigate scenarios and test hypotheses. Yet, simulation outputs are mainly used by the modellers themselves and often not easily reachable for the outside community. We have developed an open-access web-based platform for visualization and promotion of easy access to lake model output data updated in near-real time (http://simstrat.eawag.ch, last access: 29 August 2019). This platform was developed for 54 lakes in Switzerland with potential for adaptation to other regions or at global scale using appropriate forcing input data. The benefit of this data platform is practically illustrated with two examples. First, we show that the output data allows for assessing the long-term effects of past climate change on the thermal structure of a lake. The study confirms the need to not only evaluate changes in all atmospheric forcing but also changes in the watershed or throughflow heat energy and changes in light penetration to assess the lake thermal structure. Then, we show how the data platform can be used to study and compare the role of episodic strong wind events for different lakes on a regional scale and especially how their thermal structure is temporarily destabilized. With this open-access data platform, we demonstrate a new path forward for scientists and practitioners promoting a cross exchange of expertise through openly sharing in situ and model data.

scholarly journals The dynamic-thermal structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing

2020 ◽  
Author(s):  
Yunyan Jiang ◽  
Jinyuan Xin ◽  
Ying Wang ◽  
Guiqian Tang ◽  
Yuxin Zhao ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Diurnal Variation ◽  
Planetary Boundary Layer ◽  
Large Scale ◽  
Coupling Effect ◽  
Thermal Structure ◽  
Regional Scale ◽  
Vertical Shear ◽  
Strong Wind ◽  
Vertical Coupling

Abstract. Synoptic circulations play important roles in meteorological conditions and air quality within the planetary boundary layer (PBL). Based on Lamb-Jenkinson weather typing and multiple field measurements, this study reveals the mechanism of how the coupling effects of multiscale circulations influence PBL structure and pollution. Due to the topographic blocking in the daytime, pollutants accumulate in the plain areas horizontally. The sinking divergent flows overlying on the rising convergent flows within the PBL inhibit the continuously upward dispersion of aerosols vertically. At night, the horizontal and vertical coupling mechanisms synergistically worsen the pollution. The large-scale environmental winds and regional-scale breezes affect the pollution directly via the horizontal coupling effect, which generates a pollution convergent zone of different directional flows. The relative strength of flows causes the severely polluted area to move around horizontally from 39° N to 41° N. In addition, the multiscale circulations regulate the mixing and diffusion of pollutants indirectly via the vertical coupling effect, which changes the PBL dynamic-thermal structure. The warm advection transported by the upper environmental winds overlies the cold advection transported by the lower regional breezes, generating strong wind direction shear and advective inversion. The capping inversion and the convergent sinking motion within the PBL suppress massive pollutants below the zero speed zone. The multilayer PBL under cyclonic circulation has no diurnal variation. Weak ambient winds strengthen the mountain breezes observably at night, the temperature inversion can reach 900 m. The nocturnal shallower PBL, consistent with the zero velocity zone between ambient and mountain winds, can reach 600 m. By contrast, the PBL under southwesterly circulation is a mono-layer with obvious diurnal variation, reaching 2000 m in the daytime. The strong winds circulations restrain the development of regional breezes, the zero speed zone is located at 400 m and the inversion is lower than 200 m at night. The PBL under westerly circulation has a hybrid structure with both multiple aerosol layers and diurnal variation. The inversion is generated by the vertical shear of zonal winds. Clean and strong north winds are dominated under anticyclone circulation, the vertical shear and the diurnal variation of thermal field disappear because of strong turbulent mixing, and there is no significant PBL structure. Our results imply that the algorithm of atmospheric environmental capacity under synoptic circulations, such as the cyclonic type, with a multilayer PBL needs to be improved.

scholarly journals The intensity of slope and fluvial processes after a catastrophic windthrow event in small catchments in the Tatra Mountains

2021 ◽  
Vol 18 (6) ◽  
pp. 1405-1423
Author(s):  
Dariusz Strzyżowski ◽  
Elżbieta Gorczyca ◽  
Kazimierz Krzemień ◽  
Mirosław Żelazny
Keyword(s):  
Environmental Changes ◽  
Bedload Transport ◽  
Strong Wind ◽  
Tatra Mountains ◽  
Salvage Logging ◽  
Fluvial Processes ◽  
Wind Events ◽  
And Control ◽  
The Tatra Mountains ◽  
The Impact

AbstractStrong wind events frequently result in creating large areas of windthrow, which causes abrupt environmental changes. Bare soil surfaces within pits and root plates potentially expose soil to erosion. Absence of forest may alter the dynamics of water circulation. In this study we attempt to answer the question of whether extensive windthrows influence the magnitude of geomorphic processes in 6 small second- to third-order catchments with area ranging from 0.09 km2 to 0.8 km2. Three of the catchments were significantly affected by a windthrow which occurred in December 2013 in the Polish part of the Tatra Mountains, and the other three catchments were mostly forested and served as control catchments. We mapped the pits created by the windthrow and the linear scars created by salvage logging operations in search of any signs of erosion within them. We also mapped all post-windthrow landslides created in the windthrow-affected catchments. The impact of the windthrow on the fluvial system was investigated by measuring a set of channel characteristics and determining bedload transport intensity using painted tracers in all the windthrow-affected and control catchments. Both pits and linear scars created by harvesting tend to become overgrown by vegetation in the first several years after the windthrow. The only signs of erosion were observed in 10% of the pits located on convergent slopes. During the period from the windthrow event in 2013 until 2019, 5 very small (total area <100 m2) shallow landslides were created. The mean distance of bedload transport was similar (t-test, p=0.05) in most of the windthrow-affected and control catchments. The mapping of channels revealed many cases of root plates fallen into a channel and pits created near a channel. A significant amount of woody debris delivered into the channels influenced the activity of fluvial processes by creating alternating zones of erosion and accumulation.

scholarly journals A methodology to conduct wind damage field surveys for high-impact weather events of convective origin

2020 ◽  
Vol 20 (5) ◽  
pp. 1513-1531 ◽  
Author(s):  
Oriol Rodríguez ◽  
Joan Bech ◽  
Juan de Dios Soriano ◽  
Delia Gutiérrez ◽  
Salvador Castán
Keyword(s):  
Field Studies ◽  
High Impact ◽  
Strong Wind ◽  
Field Surveys ◽  
Weather Events ◽  
Straight Line ◽  
High Impact Weather ◽  
Strong Winds ◽  
Wind Events ◽  
The One

Abstract. Post-event damage assessments are of paramount importance to document the effects of high-impact weather-related events such as floods or strong wind events. Moreover, evaluating the damage and characterizing its extent and intensity can be essential for further analysis such as completing a diagnostic meteorological case study. This paper presents a methodology to perform field surveys of damage caused by strong winds of convective origin (i.e. tornado, downburst and straight-line winds). It is based on previous studies and also on 136 field studies performed by the authors in Spain between 2004 and 2018. The methodology includes the collection of pictures and records of damage to human-made structures and on vegetation during the in situ visit to the affected area, as well as of available automatic weather station data, witness reports and images of the phenomenon, such as funnel cloud pictures, taken by casual observers. To synthesize the gathered data, three final deliverables are proposed: (i) a standardized text report of the analysed event, (ii) a table consisting of detailed geolocated information about each damage point and other relevant data and (iii) a map or a KML (Keyhole Markup Language) file containing the previous information ready for graphical display and further analysis. This methodology has been applied by the authors in the past, sometimes only a few hours after the event occurrence and, on many occasions, when the type of convective phenomenon was uncertain. In those uncertain cases, the information resulting from this methodology contributed effectively to discern the phenomenon type thanks to the damage pattern analysis, particularly if no witness reports were available. The application of methodologies such as the one presented here is necessary in order to build homogeneous and robust databases of severe weather cases and high-impact weather events.

The Design of Avionics System Interfaces Emulation and Verification Platform Based on QAR Data

2014 ◽  
Vol 668-669 ◽  
pp. 879-883 ◽  
Author(s):  
Yi Gang Sun ◽  
Li Sun
Keyword(s):  
Mathematical Modeling ◽  
Theoretical Data ◽  
Environmental Data ◽  
Input Output ◽  
Output Data ◽  
Running Performance ◽  
Excitation Signal ◽  
Data Platform ◽  
System Verification ◽  
System Interfaces

In order to avoid the complex mathematical modeling and ensure the reliability of avionics system verification, this paper has designed an interfaces emulation and verification platform of avionics system based on QAR data. Platform includes 2 parts: Emulator and Simulator. Simulator generates the flight environmental data which is come from QAR and transforms the data into excitation signal of devices. Emulator emulates the interface features of avionic devices according to the ICD and can be replaced with real devices. By comparing the actual input-output data of devices with QAR theoretical data, this platform can evaluate the running performance of avionic systems or devices and the rationality of the ICD.

Lessons learnt at the Met Office from the Great Storm of 1987 - a comparison with recent strong wind events

Weather ◽  
2012 ◽  
Vol 67 (10) ◽  
pp. 268-273 ◽  
Author(s):  
Alexander Fox ◽  
Rebekah Sherwin ◽  
Fraser Ralston
Keyword(s):  
Strong Wind ◽  
Lessons Learnt ◽  
Wind Events

scholarly journals A High-Speed, Light-Weight Scalar Magnetometer Bird for km Scale UAV Magnetic Surveying: On Sensor Choice, Bird Design, and Quality of Output Data

2021 ◽  
Vol 13 (4) ◽  
pp. 649
Author(s):  
Arne Døssing ◽  
Eduardo Lima Simoes da Silva ◽  
Guillaume Martelet ◽  
Thorkild Maack Rasmussen ◽  
Eric Gloaguen ◽  
...  
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Regional Scale ◽  
Weather Conditions ◽  
Light Weight ◽  
Output Data ◽  
Efficient Manner ◽  
Flexible System ◽  
Scalar Data

Magnetic surveying is a widely used and cost-efficient remote sensing method for the detection of subsurface structures at all scales. Traditionally, magnetic surveying has been conducted as ground or airborne surveys, which are cheap and provide large-scale consistent data coverage, respectively. However, ground surveys are often incomplete and slow, whereas airborne surveys suffer from being inflexible, expensive and characterized by a reduced signal-to-noise ratio, due to increased sensor-to-source distance. With the rise of reliable and affordable survey-grade Unmanned Aerial Vehicles (UAVs), and the developments of light-weight magnetometers, the shortcomings of traditional magnetic surveying systems may be bypassed by a carefully designed UAV-borne magnetometer system. Here, we present a study on the development and testing of a light-weight scalar field UAV-integrated magnetometer bird system (the CMAGTRES-S100). The idea behind the CMAGTRES-S100 is the need for a high-speed and flexible system that is easily transported in the field without a car, deployable in most terrain and weather conditions, and provides high-quality scalar data in an operationally efficient manner and at ranges comparable to sub-regional scale helicopter-borne magnetic surveys. We discuss various steps in the development, including (i) choice of sensor based on sensor specifications and sensor stability tests, (ii) design considerations of the bird, (iii) operational efficiency and flexibility and (iv) output data quality. The current CMAGTRES-S100 system weighs ∼5.9 kg (including the UAV) and has an optimal surveying speed of 50 km/h. The system was tested along a complex coastal setting in Brittany, France, targeting mafic dykes and fault contacts with magnetite infill and magnetite nuggets (skarns). A 2.0 × 0.3 km area was mapped with a 10 m line-spacing by four sub-surveys (due to regulatory restrictions). The sub-surveys were completed in 3.5 h, including >2 h for remobilisation and the safety clearance of the area. A noise-level of ±0.02 nT was obtained and several of the key geological structures were mapped by the system.

scholarly journals Design of a scanning laser meter for monitoring the spatio-temporal evolution of snow depth and its application in the Alps and in Antarctica

2016 ◽  
Vol 10 (4) ◽  
pp. 1495-1511 ◽  
Author(s):  
Ghislain Picard ◽  
Laurent Arnaud ◽  
Jean-Michel Panel ◽  
Samuel Morin
Keyword(s):  
Spatial Variability ◽  
Snow Depth ◽  
Laser Scanning ◽  
Single Point ◽  
Measurement Techniques ◽  
Strong Wind ◽  
Slow Increase ◽  
Automatic Instrument ◽  
Spatio Temporal ◽  
Wind Events

Abstract. Although both the temporal and spatial variations of the snow depth are usually of interest for numerous applications, available measurement techniques are either space-oriented (e.g. terrestrial laser scans) or time-oriented (e.g. ultrasonic ranging probe). Because of snow heterogeneity, measuring depth in a single point is insufficient to provide accurate and representative estimates. We present a cost-effective automatic instrument to acquire spatio-temporal variations of snow depth. The device comprises a laser meter mounted on a 2-axis stage and can scan  ≈  200 000 points over an area of 100–200 m2 in 4 h. Two instruments, installed in Antarctica (Dome C) and the French Alps (Col de Porte), have been operating continuously and unattended over 2015 with a success rate of 65 and 90 % respectively. The precision of single point measurements and long-term stability were evaluated to be about 1 cm and the accuracy to be 5 cm or better. The spatial variability in the scanned area reached 7–10 cm (root mean square) at both sites, which means that the number of measurements is sufficient to average out the spatial variability and yield precise mean snow depth. With such high precision, it was possible for the first time at Dome C to (1) observe a 3-month period of regular and slow increase of snow depth without apparent link to snowfalls and (2) highlight that most of the annual accumulation stems from a single event although several snowfall and strong wind events were predicted by the ERA-Interim reanalysis. Finally the paper discusses the benefit of laser scanning compared to multiplying single-point sensors in the context of monitoring snow depth.

scholarly journals Dissolved iron (II) in the Baltic Sea surface water and implications for cyanobacterial bloom development

2009 ◽  
Vol 6 (2) ◽  
pp. 3803-3850 ◽  
Author(s):  
E. Breitbarth ◽  
J. Gelting ◽  
J. Walve ◽  
L. J. Hoffmann ◽  
D. R. Turner ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Surface Waters ◽  
Cyanobacterial Bloom ◽  
Euphotic Zone ◽  
Strong Wind ◽  
Ferrous Ions ◽  
The Baltic Sea ◽  
High Concentrations ◽  
Wind Events ◽  
The Baltic

Abstract. Iron chemistry measurements were conducted during summer 2007 at two distinct locations in the Baltic Sea (Gotland Deep and Landsort Deep) to evaluate the role of iron for cyanobacterial bloom development in these estuarine waters. Depth profiles of Fe(II) were measured by chemiluminescent flow injection analysis (CL-FIA) and reveal several origins of Fe(II) to the water column. Photoreduction of Fe(III)-complexes and deposition by rain are main sources of Fe(II) (up to 0.9 nmol L−1) in light penetrated surface waters. Indication for organic Fe(II) complexation resulting in prolonged residence times in oxygenated water was observed. Surface dwelling heterocystous cyanobacteria where mainly responsible for Fe(II) consumption in comparison to other phytoplankton. The significant Fe(II) concentrations in surface waters apparently play a major role in cyanobacterial bloom development in the Baltic Sea and are a major contributor to the Fe requirements of diazotrophs. Second, Fe(II) concentrations up to 1.44 nmol L−1 were observed at water depths below the euphotic zone, but above the oxic anoxic interface. Finally, all Fe(III) is reduced to Fe(II) in anoxic deep water. However, only a fraction thereof is present as ferrous ions (up to 28 nmol L−1) and was detected by the CL-FIA method applied. Despite their high concentrations, it is unlikely that ferrous ions originating from sub-oxic waters could be a temporary source of bioavailable iron to the euphotic zone since mixed layer depths after strong wind events are not deep enough in summer time.

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