scholarly journals Using the satellite images for the territory of Ukraine

2020 ◽  
pp. 24-36
Author(s):  
M. M. Koman
Keyword(s):  
Wind Speed ◽  
Brightness Temperature ◽  
Wind Direction ◽  
Satellite Images ◽  
Satellite Image ◽  
Time Interval ◽  
Direction Vector ◽  
Air Masses ◽  
Forecast Models ◽  
Tracking Module

The purpose of this article is to identify the wind direction and speed using the images from geostationary satellites and through application of two-dimensional wind vectors, the magnitude and direction of which corresponds to the speed and direction of cloud masses, on a satellite image. The results may be used for making a short-term forecast of dangerous weather events within the territory of Ukraine. To make the technique work, it is necessary to select cloud areas on a satellite image using the threshold method. Then, based on the brightness temperature distribution between two tracking modules (parts of an image based on which two consecutive satellite images are compared), the maximum correlation coefficient for infrared brightness temperature is to be determined. The coefficient corresponds to the movement of cloud masses and sets the beginning and end of the wind direction vector. To determine the optimum application of the  technique for the territory of Ukraine, the analysis of accuracy of tracking modules of different sizes was also performed. The analysis revealed that the accuracy of determining the wind vector direction depends on the tracking module size: the larger it is, the more accurate is the direction vector found, but given that the time interval between images is 15 minutes, the optimum algorithm to be used in Ukraine is the one with 5x5 pixel tracking module. The technique performance was also compared with the data of ICON and GFS forecast models. The results of the applied algorithm showed that the direction of air masses was more reliable than the data retrieved from the above-mentioned forecast models, because the algorithm analyzes the real-time movement of air masses while the forecast models assess the formation and movement of air masses in advance (with an interval of several hours up to dozens of hours). Numerical wind speed forecast of ICON and GFS models is more accurate, because the algorithm determines the wind speed based on the movement of cloud masses on satellite images whereas the forecast models consider several factors (pressure fields, development and subsequent evolution of cyclones, anticyclones, geographical characteristics etc.) which makes them more realistic.

scholarly journals Wind Characteristics Investigation on The Roofs of Three Adjacent High-Rise Buildings in a Coastal Area during Typhoon Meranti

2019 ◽  
Vol 9 (3) ◽  
pp. 367 ◽  
Author(s):  
Chequan Wang ◽  
Zhengnong Li ◽  
Qizhi Luo ◽  
Lan Hu ◽  
Zhefei Zhao ◽  
...  
Keyword(s):  
Wind Speed ◽  
Turbulence Intensity ◽  
Wind Direction ◽  
Time Interval ◽  
Integral Scale ◽  
High Rise ◽  
Wind Turbulence ◽  
Mean Wind Speed ◽  
The Mean ◽  
Gust Factors

This paper presents the study of the pulsating characteristics of three adjacent high-rise buildings A, B, and C under typhoon ‘Moranti’ (2016) based on the measurement of the actual top wind speed. The studied pulsating characteristics included mean wind speed and direction, turbulence intensity, gust factor, turbulence integral scale, wind speed spectrum and correlation. The relationships between each pulsating parameter and the relationship between the pulsating parameter and gust duration have been investigated. Results show that the mean wind speed and wind direction of three buildings are close. When U ≥ 10 m/s in three different sites at the same time, the turbulence intensity variation of three buildings is consistent and decreases when mean wind speed increases. Once only two locations are acquired simultaneously and the wind angle between 35° and 45°, the mean values of the along-wind and cross-wind turbulence of building A and building C are close. The along-wind turbulence of the three buildings is greater than the predicted Chinese codes for various terrains. The turbulence intensity and gust factors obtained through the analysis of the samples with the mean wind speed U ≥ 10 m/s are reasonable. The turbulence integral scales of buildings A and C are equal to the predicted values of ASCE-7 and AIJ-2004, whereas the turbulent integral scale of building B is evidently small. The gust factors of three buildings increase when the turbulence intensity increases; these two characteristics have a linear relationship. At the same time interval, building B has the maximum along-wind turbulence intensity and gust factors during the low wind speed period and building C achieves the minimum values. Building A acquires the maximum and building C obtains the minimum values in the high wind speed period. The turbulence intensity and gust factors of building B show a certain pulsation. Results show that turbulence intensity and gust factors are mainly affected by the short-term fluctuation of wind. The longitudinal wind speed spectrum of three buildings conforms well to the von Karman model. The correlation of along-wind speed depends on the wind speed, whereas the correlation of cross-wind direction is independent of wind speeds. The measured data and statistical parameters provide useful information for the wind resistance design of high-rise buildings in typhoon-prone areas.

Off-Nadir SFMR Brightness Temperature Measurements in High-Wind Conditions

2018 ◽  
Vol 35 (9) ◽  
pp. 1865-1879 ◽  
Author(s):  
Heather M. Holbach ◽  
Eric W. Uhlhorn ◽  
Mark A. Bourassa
Keyword(s):  
Wind Speed ◽  
Brightness Temperature ◽  
Wind Direction ◽  
Wave Breaking ◽  
Surface Brightness ◽  
Surface Wind ◽  
Ocean Surface ◽  
Temperature Measurements ◽  
High Wind ◽  
Wide Range

AbstractWind and wave-breaking directions are investigated as potential sources of an asymmetry identified in off-nadir remotely sensed measurements of ocean surface brightness temperatures obtained by the Stepped Frequency Microwave Radiometer (SFMR) in high-wind conditions, including in tropical cyclones. Surface wind speed, which dynamically couples the atmosphere and ocean, can be inferred from SFMR ocean surface brightness temperature measurements using a radiative transfer model and an inversion algorithm. The accuracy of the ocean surface brightness temperature to wind speed calibration relies on accurate knowledge of the surface variables that are influencing the ocean surface brightness temperature. Previous studies have identified wind direction signals in horizontally polarized radiometer measurements in low to moderate (0–20 m s−1) wind conditions over a wide range of incidence angles. This study finds that the azimuthal asymmetry in the off-nadir SFMR brightness temperature measurements is also likely a function of wind direction and extends the results of these previous studies to high-wind conditions. The off-nadir measurements from the SFMR provide critical data for improving the understanding of the relationships between brightness temperature, surface wave–breaking direction, and surface wind vectors at various incidence angles, which is extremely useful for the development of geophysical model functions for instruments like the Hurricane Imaging Radiometer (HIRAD).

scholarly journals Spectral and statistical analysis of wind spectrum for Ali Al-Gharbi area in Iraq

2019 ◽  
pp. 1649-1657
Author(s):  
Taghreed Ali Abbas ◽  
Monim Hakim Khalaf ◽  
Amani I. Altmimi
Keyword(s):  
Fourier Transform ◽  
Statistical Analysis ◽  
Wind Speed ◽  
Spectral Density ◽  
Wind Direction ◽  
Time Interval ◽  
Night Time ◽  
The North ◽  
Specific Parameter ◽  
One Year

The spectrum known represented as a relationship that’s plotted between the magnitudes or energy for a specific parameter vs. its frequency, the wind spectrum is presented as the sum of wind speed created by events divided either in space, in time, or both. This paper presents a wind speed spectrum demonstration inAli Al-Gharbi location in Iraq. The aim of the present paper is to analysis the wind speed and direction by employing the FFT (Fast Fourier Transform) therefore field measurement of wind speed and direction were collected for one year from Dec 2014 to Dec 2015 in the time interval of 10 minutes at heights of 10, 30 and 50meters. From the performance of the FFT it was found that the values of the peak which contains the highest spectral density was (226236.282 m/sec) at the frequency of (2 Hz) on the 50 m height level throughout the night time but the lowest was (115863.7 m/sec) at the frequency of (2 Hz) at the 10 m height throughout the night time. The dominant wind direction at the area was from west-Northwest and the north-Northwest. The wind speed during morning hours was higher than that at the night time.

scholarly journals Detection of Parking Cars in Stereo Satellite Images

2020 ◽  
Vol 12 (13) ◽  
pp. 2170 ◽  
Author(s):  
Sebastian Zambanini ◽  
Ana-Maria Loghin ◽  
Norbert Pfeifer ◽  
Elena Màrmol Soley ◽  
Robert Sablatnig
Keyword(s):  
Satellite Images ◽  
Satellite Image ◽  
Static Condition ◽  
Surface Model ◽  
Time Interval ◽  
Digital Surface Model ◽  
Parking Space ◽  
Stereo Images ◽  
Car Detection ◽  
Depth Analysis

In this paper, we present a Remote Sens. approach to localize parking cars in a city in order to enable the development of parking space availability models. We propose to use high-resolution stereo satellite images for this problem, as they provide enough details to make individual cars recognizable and the time interval between the stereo shots allows to reason about the moving or static condition of a car. Consequently, we describe a complete processing pipeline where raw satellite images are georeferenced, ortho-rectified, equipped with a digital surface model and an inclusion layer generated from Open Street Model vector data, and finally analyzed for parking cars by means of an adapted Faster R-CNN oriented bounding box detector. As a test site for the proposed approach, a new publicly available dataset of the city of Barcelona labeled with parking cars is presented. On this dataset, a Faster R-CNN model directly trained on the two ortho-rectified stereo images achieves an average precision of 0.65 for parking car detection. Finally, an extensive empirical and analytical evaluation shows the validity of our idea, as parking space occupancy can be broadly derived in fully visible areas, whereas moving cars are efficiently ruled out. Our evaluation also includes an in-depth analysis of the stereo occlusion problem in view of our application scenario as well as the suitability of using a reconstructed Digital Surface Model (DSM) as additional data modality for car detection. While an additional adoption of the DSM in our pipeline does not provide a beneficial cue for the detection task, the stereo images provide essentially two views of the dynamic scene at different timestamps. Therefore, for future studies, we recommend a satellite image acquisition geometry with smaller incidence angles, to decrease occlusions by buildings and thus improve the results with respect to completeness.

scholarly journals 2.5D Flexible Wind Sensor Using Differential Plate Capacitors

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3101
Author(s):  
Yu Wan ◽  
Zhenxiang Yi
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Parallel Plate ◽  
Electrode Array ◽  
Copper Electrode ◽  
Windward Side ◽  
Leeward Side ◽  
Electrode Layer ◽  
Young’S Moduli ◽  
Speed Up

In this paper, a novel 2.5-dimensional (2.5D) flexible wind sensor is proposed based on four differential plate capacitors. This design consists of a windward pillar, two electrode layers, and a support layer, which are all made of polydimethylsiloxane (PDMS) with different Young’s moduli. A 2 mm × 2 mm copper electrode array is located on each electrode layer, forming four parallel plate capacitors as the sensitive elements. The wind in the xy-plane tilts the windward pillar, decreasing two capacitances on the windward side and increasing two capacitances on the leeward side. The wind in the z-axis depresses the windward pillar, resulting in an increase of all four capacitances. Experiments demonstrate that this sensor can measure the wind speed up to 23.9 m/s and the wind direction over the full 360° range of the xy-plane. The sensitivities of wind speed are close to 4 fF·m−1·s and 3 fF·m−1·s in the xy-plane and z-axis, respectively.

Movement of Large Convective Rainstorms in Relation to Winds Aloft

1958 ◽  
Vol 39 (3) ◽  
pp. 129-136 ◽  
Author(s):  
C. W. Newton ◽  
Sey Katz
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Rainfall Data ◽  
Squall Lines ◽  
Hourly Rainfall ◽  
The Difference ◽  
Strong Winds

By means of hourly rainfall data from the Hydroclimatic Network, the motions of large rainstorms, of the kind associated with squall lines, are examined in relation to the winds aloft. Very little correlation is found between the speed of movement of the rainstorms and the wind speed at any level, although the fastest moving storms were associated with strong winds aloft. Significant correlation is found between direction of motion of rainstorms, and wind direction at 700 mb or higher levels. On the average, the rainstorms move with an appreciable component toward right of the wind direction. The difference between these results, and those from other studies based on small precipitation areas, is ascribed to propagation. The mechanism involved is discussed briefly.

scholarly journals Surface gas pollutants in Lhasa, a highland city of Tibet – current levels and pollution implications

2014 ◽  
Vol 14 (19) ◽  
pp. 10721-10730 ◽  
Author(s):  
L. Ran ◽  
W. L. Lin ◽  
Y. Z. Deji ◽  
B. La ◽  
P. M. Tsering ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Fossil Fuels ◽  
Trace Gases ◽  
Early Morning ◽  
Current Status ◽  
Urban Site ◽  
Large Variability ◽  
Mixing Ratios ◽  
Low Wind Speed

Abstract. Through several years of development, the city of Lhasa has become one of the most populated and urbanized areas on the highest plateau in the world. In the process of urbanization, current and potential air quality issues have been gradually concerned. To investigate the current status of air pollution in Lhasa, various gas pollutants including NOx, CO, SO2, and O3, were continuously measured from June 2012 to May 2013 at an urban site (29.40° N, 91.08° E, 3650 m a.s.l.). The seasonal variations of primary gas pollutants exhibited a peak from November to January with a large variability. High mixing ratios of primary trace gases almost exclusively occurred under low wind speed and showed no distinct dependence on wind direction, implying local urban emissions to be predominant. A comparison of NO2, CO, and SO2 mixing ratios in summer between 1998 and 2012 indicated a significant increase in emissions of these gas pollutants and a change in their intercorrelations, as a result of a substantial growth in the demand of energy consumption using fossil fuels instead of previously widely used biomass. The pronounced diurnal double peaks of primary trace gases in all seasons suggested automobile exhaust to be a major emission source in Lhasa. The secondary gas pollutant O3 displayed an average diurnal cycle of a shallow flat peak for about 4–5 h in the afternoon and a minimum in the early morning. Nighttime O3 was sometimes completely consumed by the high level of NOx. Seasonally, the variations of O3 mixing ratios displayed a low valley in winter and a peak in spring. In autumn and winter, transport largely contributed to the observed O3 mixing ratios, given its dependence on wind speed and wind direction, while in spring and summer photochemistry played an important role. A more efficient buildup of O3 mixing ratios in the morning and a higher peak in the afternoon was found in summer 2012 than in 1998. An enhancement in O3 mixing ratios would be expected in the future and more attention should be given to O3 photochemistry in response to increasing precursor emissions in this area.

Numerical Investigation of Thermal Flow Field of Air-Cooled Condensers for Yongshou Plant

2012 ◽  
Vol 248 ◽  
pp. 391-394
Author(s):  
Wen Zhou Yan ◽  
Wan Li Zhao ◽  
Qiu Yan Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Power Plant ◽  
Flow Field ◽  
Wind Direction ◽  
Rotational Speed ◽  
Power Plants ◽  
Thermal Flow ◽  
Air Cooled Condensers

By using the computational fluid dynamics code, FLUENT, Numerically simulation is investigated for Youngshou power plant. Under the constant ambient temperature, the effects of different wind speed and wind direction on the thermal flow field are qualitatively considered. It was found that when considering about the existing and normally operating power plants, the thermal flow field is more sensitive to wind direction and wind speed. Based on the above results, three improved measures such as: increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively improving the thermal flow field, and enhanced the heat dispersal of ACC.

Time scale dependence of wind speed patterns - implications for wind power site assessment

2021 ◽  
Author(s):  
Cristian Suteanu
Keyword(s):  
Wind Speed ◽  
Wind Power ◽  
Practical Importance ◽  
Sampling Rate ◽  
Fluctuation Analysis ◽  
Time Interval ◽  
Time Averaging ◽  
Time Intervals ◽  
Site Assessment ◽  
Wind Pattern

<p>Characterizing properties of wind speed variability and their dependence on the temporal scale is important: from sub-second intervals (for the design and monitoring of wind turbines) to longer time scales – months, years (for the evaluation of the wind power potential). Wind speed data are usually reported as averages over time intervals of various length (minutes, days, months, etc). The research project presented in this paper addressed the following questions: What aspects of the wind pattern are changed, in what ways and to what extent, in the process of producing time-averaged values? What precautions should be considered when time-averaged values are used in the assessment of wind variability? What are the conditions to be fulfilled for a meaningful comparison of wind pattern characteristics obtained in distinct studies? Our research started from wind speed records sampled at 0.14 second intervals, which were averaged over increasingly longer time intervals. Variability evaluation was based on statistical moments, L-moments, and detrended fluctuation analysis. We present the change suffered by characteristics of temporal variability as a function of sampling rate and the averaging time interval. In particular, the height dependence of wind speed variability, which is of theoretical and practical importance, is shown to be progressively erased when averaging intervals are increased. The paper makes recommendations regarding the interpretation of wind pattern characteristics obtained at different sites as a function of sampling rate and time-averaging intervals.</p>

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