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Wintertime Local Wind Dynamics from Scanning Doppler Lidar and Air Quality in the Arve River Valley
摘要： Air quality issues are frequent in urbanized valleys, particularly in wintertime when a temperature inversion forms and the air within the valley is stably stratified over several days. In addition to pollutant sources, local winds can have a significant impact on the spatial distribution and temporal evolution of pollutant concentrations. They can be very complex and difficult to represent in numerical weather prediction models, particularly under stable conditions. Better knowledge of these local winds from observations is also a prerequisite to improving air quality prediction capability. This paper analyses local winds during the Passy-2015 field experiment that took place in a section of the Arve river valley, near Chamonix–Mont-Blanc. This location is one of the worst places in France regarding air quality. The wind analysis, which is mainly based on scanning Doppler lidar data sampling a persistent temperature inversion episode, reveals features consistent with the higher pollutant concentrations observed in this section of the valley as well as their spatial heterogeneities. In particular, an elevated down-valley jet is observed at night in the northern half of the valley, which, combined with a weak daytime up-valley wind, leads to very poor ventilation of the lowest layers. A northeast–southwest gradient in ventilation is observed on a daily-average, and is consistent with the PM10 heterogeneities observed within the valley.
关键词： scanning Doppler wind lidar,Passy-2015 field experiment,cold air pool,local wind dynamics,air quality,alpine valley
更新于2025-09-23 15:23:52
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Results from the validation campaign of the ozone radiometer GROMOS-C at the NDACC station of La Réunion Island
摘要： Ozone is a species of primary interest as it performs a key role in the middle atmosphere and its monitoring is thus necessary. At the Institute of Applied Physics of the University of Bern, Switzerland, we built a new ground based microwave radiometer, GROMOS-C (GRound based Ozone MOnitoring System for Campaigns). It has a compact design and can be operated at remote places with very little maintenance requirements, being therefore suitable for remote deployments. It has been conceived to measure the vertical distribution of ozone in the middle atmosphere, by observing pressure broadened emission spectra at a frequency of 110.836 GHz. In addition, meridional and zonal wind profiles can be retrieved, based on the Doppler shift of the ozone line measured in the 4 directions of observation (North-East-South-West). In June 2014 the radiometer was installed in the Ma?do observatory, on La Réunion Island (21.2°S, 55.5°E). High resolution ozone spectra were continuously recorded during 7 months. Vertical profiles of ozone have been retrieved through an optimal estimation inversion process, using the Atmospheric Radiative Transfer Simulator ARTS2 as the forward model. The best estimate of the vertical profile is done by means of the optimal estimation method. The validation is performed against ozone profiles from the Microwave Limb Sounder (MLS) on the Aura satellite, the ozone lidar located in the observatory and with ozone profiles from weekly radiosondes. Zonal and meridional winds retrieved from GROMOS-C data are validated against another wind radiometer located in situ, WIRA. In addition, we compare both ozone and winds with ECMWF model data. Results show that GROMOS-C provides reliable ozone profiles between 30 to 0.02 hPa. The comparison with lidar shows a very good agreement at all levels. The accordance with MLS is within less than 10% for pressure levels between 25 and 0.2 hPa.
关键词： ozone,validation,wind profiles,microwave radiometer,middle atmosphere,GROMOS-C
更新于2025-09-23 15:23:52
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Simulated and observed horizontal inhomogeneities of optical thickness of Arctic stratus
摘要： Two-dimensional (2D) horizontal fields of cloud optical thickness derived from airborne measurements of solar spectral radiance during the Vertical Distribution of Ice in Arctic Clouds (VERDI) campaign (carried out in Inuvik, Canada in April/May 2012) are compared with semi-idealized Large Eddy Simulations (LES) of Arctic stratus performed with the COnsortium for Small-Scale MOdeling (COSMO) atmospheric model. The input for the LES is obtained from collocated airborne dropsonde observations. Four consecutive days of a persistent Arctic stratus observed above the sea-ice free Beaufort Sea are selected for the comparison. Macrophysical cloud properties such as cloud top altitude and vertical extent are well captured by COSMO. Cloud horizontal inhomogeneity quantified by the standard deviation and one-dimensional (1D) inhomogeneity parameters show that COSMO produces only half of the measured horizontal cloud inhomogeneities, while the directional structure of the cloud inhomogeneity is well represented by the model. Differences between the individual cases are mainly associated with the wind shear near cloud top and the vertical structure of the atmospheric boundary layer. A sensitivity study changing the wind velocity in COSMO by a vertically constant scaling factor shows that the directional cloud inhomogeneity structures strongly depend on the mean wind speed. A threshold wind velocity is identified, which determines when the cloud inhomogeneity stops increasing with increasing wind velocity.
关键词： airborne measurements,COSMO model,horizontal inhomogeneity,wind speed sensitivity,Large Eddy Simulation,Arctic stratus,cloud optical thickness
更新于2025-09-23 15:23:52
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InSight Auxiliary Payload Sensor Suite (APSS)
摘要： NASA’s InSight mission to Mars will measure seismic signals to determine the planet’s interior structure. These highly sensitive seismometers are susceptible to corruption of their measurements by environmental changes. Magnetic fields, atmosphere pressure changes, and local winds can all induce apparent changes in the seismic records that are not due to propagating ground motions. Thus, InSight carries a set of sensors called the Auxiliary Payload Sensor Suite (APSS) which includes a magnetometer, an atmospheric pressure sensor, and a pair of wind and air temperature sensors. In the case of the magnetometer, knowledge of the amplitude of the fluctuating magnetic field at the InSight lander will allow the separation of seismic signals from potentially interfering magnetic signals of either natural or spacecraft origin. To acquire such data, a triaxial fluxgate magnetometer was installed on the deck of the lander to obtain magnetic records at the same cadence as the seismometer. Similarly, a highly sensitive pressure sensor is carried by InSight to enable the removal of local ground-surface tilts due to advecting pressure perturbations. Finally, the local winds (speed and direction) and air temperature are estimated using a hot-film wind sensor with heritage from REMS on the Curiosity rover. When winds are too high, seismic signals can be ignored or discounted. Herein we describe the APSS sensor suite, the test programs for its components, and the possible additional science investigations it enables.
关键词： Wind,Magnetometer,Spacecraft,Pressure,Temperature,Instruments
更新于2025-09-23 15:23:52
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Consideration of the Impact of the Environmental Conditions when Designing Heat-Receiving Systems of the Solar Cylindrical Parabolic Modules
摘要： The aerohydrodynamic and heat exchange characteristics in the cylindrical heat receiver of a solar cylindrical parabolic concentrating module are investigated. The mathematical model is based on the Navier-Stokes equation system for a laminar flow in a channel. The model is implemented using the control volume method. The created computer algorithm allows carrying out parametric studies and revealing the most rational geometric, dynamic, and power parameters of the process. The proposed model describes the general physical outlines of the heat exchange in a cylindrical heat receiver which allows estimating the influence of the environment—wind velocity, ambient temperature, etc.—on it.
关键词： cylindrical heat receiver,rational geometric, dynamic, and power parameters,solar cylindrical parabolic module,wind velocity,Navier-Stokes equation system,ambient temperature,control volume method
更新于2025-09-23 15:23:52
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Integrated sizing of hybrid PV-wind-battery system for remote island considering the saturation of each renewable energy resource
摘要： The proliferation of renewable energy particularly the combination of solar-wind power and storage bank, is likely to be occupied throughout the world, to mitigate the local energy concerns, improve the energy supply opportunities for off-grid communities and vitiate environmental pollution concerns as well as ease the intensity of energy consumption. To mitigate the disharmony between renewable energy (RE) generation and supply, a cost-optimal autonomous hybrid renewable energy system is developed and comparatively analyzed, considering the saturation level of each involved RE source based on various technical and economic key indicators. This study proposes a mathematical model to comprehensively analyze the effect of varying saturation, i.e. increasing the saturation of one resource meanwhile decreasing the ratio of other resource, on battery bank size, state of charge (SOC), loss of power supply, excess energy, net present cost, levelized cost of energy (COE) and payback time. A saturation factor is introduced, from 0 to 1 value with step size 0.02, where zero represents the wind-only system and one represents the solar-only system. Three different systems are considered, with different wind turbine sizes (total 150 configurations), to comparatively analyze the different energy systems and the result reveals that smaller wind turbine size (2 kW) with 90% saturation of wind energy is the most cost-effective system for the proposed remote island. In addition, the solar-alone and wind-alone systems are compared, showing that the wind-only system can provide good performance as compare to solar-only. Furthermore, the effects of the saturation factor on COE, battery bank size, SOC, excess energy, system reliability and different load demands are analyzed. Energy balance analysis of whole year and simulation performance of the system is accomplished to verify the system reliability. Sensitivity analysis reveals that wind energy, battery cost and load has a significant impact on COE than other factors.
关键词： Hybrid Renewable system reliability,Cost of energy,Net present cost,Renewable energy saturation,Energy balance,Solar-wind-battery system
更新于2025-09-23 15:23:52
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Complementarity between Solar and Wind Energy Potentials in Benin Republic
摘要： This paper presents a study to show the complementarity between solar and wind energy potentials in Benin Republic. Daily wind speed data in the coast of Cotonou city, precisely in Cadjehoun district, has been used to assess wind energy potential. Solar potential is evaluated using spatio temporal daily solar radiation data covering the country. In this research, we have found the locations offering optimal complementarity between solar and wind energy. The complementarity is measured with Pearson correlation coefficient, which is used as objective function to be minimized. The optimization method used is Particle Swarm Optimization (PSO), which has been implemented in Matlab?. We showed that an optimal complementarity is obtained between the coast of Cotonou in the ‘Littoral’ department and the central part of the country in the ‘Collines’ department.
关键词： solar,wind energy,Pearson coefficient,Complementarity
更新于2025-09-23 15:23:52
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[IEEE 2018 2nd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Saratov, Russia (2018.10.8-2018.10.10)] 2018 2nd School on Dynamics of Complex Networks and their Application in Intellectual Robotics (DCNAIR) - Autonomous Power Supply System of Magnetron Generators Group
摘要： The issues which emerge at autonomous power supply system development are considered. The objects of power supply are magnetron generators groups as part of technological complex with a distributed supply of microwave energy.
关键词： solar panels,wind generator,power supply system,diesel generator,magnetron
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Wind Direction Ambiguity Removal Using Along-Track Insar: A Case Study
摘要： The main problem in wind retrieval using SAR imagery is the lack of the wind direction information. A few methods have been proposed to extract the wind direction from SAR images. The main limitation of these methods is the 180o ambiguity in the direction. Usually, an external source of wind direction is used to remove this ambiguity. This study exploits the Along-track Interferometric SAR (ATI-SAR) phase to demonstrate its usefulness to tackle this problem. A method is proposed to remove the wind direction ambiguity using the ATI-SAR phase information. This is based on the fact that the interferometric phase is related to the sea surface motion direction. Depending on the sign convention, the phase is positive/negative for advancing/receding target respectively. This effect is used to assist the wind extraction algorithm to select the most plausible direction. The results show a very good agreement with atmospheric model and visual investigation.
关键词： InSAR,TerraSAR-X,wind direction,ocean surface wind
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Validation of Wave and Wind Product of the New Phase Saral Using Buoys Data
摘要： Since July 4th 2016, the SARAL/Altika has been moved in a new orbit, and it has continuously provided wave height measurements for more than 1 year. Before using these data, the measurements need to be validated. Based on the in-situ buoys from the National Data Buoy Center (NDBC), the SARAL Ka-band significant wave height (SWH) and Sea Surface Wind (SSW) measurements were validated and have been corrected using a linear regression with in-situ measurements. Compared with NDBC data, the validation results of SARAL show a RMS (Root Mean Square) of 0.28 m for SARAL SWH measurements and RMS of 1.30m/s for SARAL SSW speed indicating capability of AltiKa providing SWH and wind speed products with reliable accuracy. Therefore the accuracy of SARAL SWH products is higher than that of Jason-1/2 SWH data, and does not require any correction.
关键词： Sea Surface Wind,SARAL/AltiKa,Validation,Root Mean Square,Significant Wave Height
更新于2025-09-23 15:22:29