scholarly journals Space-borne radar observation of near-surface wind effect on anomalously highly-directional backscattering of radio waves from Aeolian processes of sand and dust transporting in desert regions

2020 ◽  
pp. 4-8
Author(s):  
Dmitro Bychkov ◽  
Viktor Ivanov ◽  
Aleksandr Matveyev ◽  
Valeriy Tsymbal ◽  
Sergey Yatsevich
Keyword(s):  
Remote Sensing ◽  
Surface Wind ◽  
Transport Processes ◽  
Dust Particles ◽  
Radio Waves ◽  
Near Surface ◽  
Radar Remote Sensing ◽  
Aeolian Processes ◽  
Dust Transport ◽  
Desert Regions

Aeolian process of sand and dust transporting is known to form the near-ground surface structures over vast territories and fill the atmosphere up with suspended aerosols-like dust particles which are spread then by winds over long distances. The presence of atmospheric dust in the planet's environment is one of the factors affecting the temperature and climatic conditions of vast regions of the Earth. A number of publications (Ivanov et al., 2015; Ivanov et al., 2016; Ivanov et al., 2016; Ivanov et al., 2018) analyze the revealed effect of anomalously highly(narrow) directed backscattering of radio waves which manifests itself in radar remote sensing (in range of local irradiation angles θ ≈ 31°÷32°) in areas covered with deep sand. At the same time, there is no specific data available from published studies investigating the impact of the near-surface wind on anomalously highly-directional backscattering of radio waves based on the results of radar remote sensing researches of Aeolian sand and dust transport processes in desert regions that, in turn, could have been used later to determine the parameters of such transport process. This article presents the results of analysis of the data obtained from long-term studies of desert regions of El-Djuf, Akshar and Trarza in Mauritania by means of space-borne SAR Envisat-1. The purpose of the analysis was actually to identify the specifics of the effect that the near-surface wind has on the anomalously highly-directional backscattering of radio waves which is identified by radar based researches of Aeolian processes of sand and dust transport in desert regions, so can be used for remote determination of such transportation parameters.

Radar remote sensing of springtime near-surface soil thaw events at mid-latitudes

2011 ◽  
Vol 32 (23) ◽  
pp. 8555-8574 ◽  
Author(s):  
Lijian Han ◽  
Atsushi Tsunekawa ◽  
Mitsuru Tsubo
Keyword(s):  
Remote Sensing ◽  
Surface Soil ◽  
Near Surface ◽  
Radar Remote Sensing

scholarly journals Adaptive Thermal Image Velocimetry of spatial wind movement on landscapes using near target infrared cameras

2021 ◽  
Author(s):  
Benjamin Schumacher ◽  
Marwan Katurji ◽  
Jiawei Zhang ◽  
Peyman Zawar-Reza ◽  
Benjamin Adams ◽  
...  
Keyword(s):  
Spatial Information ◽  
Turbulent Transport ◽  
Surface Wind ◽  
Infrared Camera ◽  
Thermal Image ◽  
Transport Processes ◽  
Near Surface ◽  
Remote Sensing Technique ◽  
Sonic Anemometers ◽  
Image Velocimetry

Abstract. Thermal Image Velocimetry (TIV) is a near-target remote sensing technique for estimating two- dimensional near-surface wind velocity based on spatiotemporal displacement of fluctuations in surface brightness temperature captured by an infrared camera. The addition of an automated parameterization and the combination of ensemble TIV results into one output made the method more suitable to changing meteorological conditions and less sensitive to noise stemming from the airborne sensor platform. Three field campaigns were carried out to evaluate the algorithm over turf, dry grass and wheat stubble. The derived velocities were validated with independently acquired observations from fine wire thermocouples and sonic anemometers. It was found that the TIV technique correctly derives atmospheric flow patterns close to the ground. Moreover, the modified method resolves wind speed statistics close to the surface at a higher resolution than the traditional measurement methods. Adaptive Thermal Image Velocimetry (A-TIV) is capable of providing contact-less spatial information about near-surface atmospheric motion and can help to be a useful tool in researching turbulent transport processes close to the ground.

scholarly journals Measurement Report: Determination of aerosol vertical features on different time-scales over East Asia based on CATS aerosol products

2020 ◽  
Author(s):  
Yueming Cheng ◽  
Tie Dai ◽  
Jiming Li ◽  
Guangyu Shi
Keyword(s):  
Seasonal Variation ◽  
Tibetan Plateau ◽  
East Asia ◽  
North China ◽  
Surface Wind ◽  
Diurnal Variations ◽  
Dust Particles ◽  
The Tibetan Plateau ◽  
Anthropogenic Aerosols ◽  
Near Surface

Abstract. The Cloud-Aerosol Transport System (CATS) lidar, on board the International Space Station (ISS), provides a new opportunity for studying aerosol vertical distributions, especially the diurnal variations from space observations. In this study, we investigate the seasonal variations and diurnal cycles of the vertical aerosol extinction coefficients (AECs) over East Asia by taking advantage of 32 months of the continuous and uniform aerosol measurements from the CATS lidar. Over the Tibetan Plateau, a belt of AECs approximately 6 km between 30° N and 38° N persistently exists in all seasons with an obviously seasonal variation. In summer, the aerosols at 6 km are identified as a mixture of both anthropogenic aerosols transported from India and coarse dust particles from Asian dust sources. In addition, the high AECs up to 8 km in summer over the Tibetan Plateau are caused by smoke aerosols from thermal dynamic processes. In fall and winter, the north slope of the plateau is continuously influenced by both dust aerosols and polluted aerosols transported upslope from the cities located in northwestern Asia at lower elevations. The diurnal variation of AECs in North China is mainly related to the diurnal variations of the transported dust and local polluted aerosols. Below 2 km, the AEC profiles in North China at 06:00 local Time (LT) and 12:00 LT are significantly higher than those at 00:00 LT and 18:00 LT, reaching the maximum at midday. The aerosol vertical profiles over the Tarim desert region in summer have obvious diurnal variations with the AECs at 12:00 LT and 18:00 LT being significantly higher than those at 00:00 LT and 06:00 LT, which are induced by the strongly diurnal variations in near-surface wind speeds. In addition, the peak of the AEC profiles has a significant seasonal variation, which is mainly determined by the boundary layer height.

IDENTIFYING NEAR SURFACE SALT DIAPIRS IN ARID ENVIRONMENTS USING OPTICAL AND RADAR REMOTE SENSING

2018 ◽  
Author(s):  
Hannah G. Pankratz ◽  
◽  
Mohamed Sultan ◽  
Saleh Al Sefry ◽  
Hassan Al-Harbi ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Arid Environments ◽  
Near Surface ◽  
Radar Remote Sensing

scholarly journals Measurement Report: Determination of aerosol vertical features on different timescales over East Asia based on CATS aerosol products

2020 ◽  
Vol 20 (23) ◽  
pp. 15307-15322
Author(s):  
Yueming Cheng ◽  
Tie Dai ◽  
Jiming Li ◽  
Guangyu Shi
Keyword(s):  
Seasonal Variation ◽  
Tibetan Plateau ◽  
East Asia ◽  
North China ◽  
Surface Wind ◽  
Diurnal Variations ◽  
Dust Particles ◽  
The Tibetan Plateau ◽  
Anthropogenic Aerosols ◽  
Near Surface

Abstract. The Cloud-Aerosol Transport System (CATS) lidar, on board the International Space Station (ISS), provides a new opportunity for studying aerosol vertical distributions, especially the diurnal variations, from space observations. In this study, we investigate the seasonal variations and diurnal cycles in the vertical aerosol extinction coefficients (AECs) over East Asia by taking advantage of 32 months of continuous and uniform aerosol measurements from the CATS lidar. Over the Tibetan Plateau, a belt of AECs at approximately 6 km between 30 and 38∘ N persistently exists in all seasons with an obvious seasonal variation. In summer, the aerosols at 6 km are identified as a mixture of both anthropogenic aerosols transported from India and coarse dust particles from Asian dust sources. In addition, the high AECs up to 8 km in summer over the Tibetan Plateau are caused by smoke aerosols from thermal dynamic processes. In fall and winter, the northern slope of the plateau is continuously influenced by both dust aerosols and polluted aerosols transported upslope from cities located at lower elevations in northwestern Asia. The diurnal variation in AECs in North China is mainly related to the diurnal variations in the transported dust and local polluted aerosols. Below 2 km, the AEC profiles in North China at 06:00 and 12:00 CST (China standard time) are significantly higher than those at 00:00 and 18:00 CST, reaching a maximum at midday. The aerosol vertical profiles over the Tarim Desert region in summer have obvious diurnal variations, and the AECs at 12:00 and 18:00 CST are significantly higher than those at 00:00 and 06:00 CST, which are induced by the strong diurnal variations in near-surface wind speeds. In addition, the peak in the AEC profiles has a significant seasonal variation, which is mainly determined by the boundary layer height.

Saturn's E, G and F rings: modulated by the plasma sheet

1984 ◽  
Vol 75 ◽  
pp. 597
Author(s):  
E. Grün ◽  
G.E. Morfill ◽  
T.V. Johnson ◽  
G.H. Schwehm
Keyword(s):  
Solar Wind ◽  
Direct Contact ◽  
Transport Processes ◽  
Time Variable ◽  
Dust Particles ◽  
Spatial Diffusion ◽  
Drag Forces ◽  
Orbit Perturbation ◽  
Time Variations ◽  
F Ring

ABSTRACTSaturn's broad E ring, the narrow G ring and the structured and apparently time variable F ring(s), contain many micron and sub-micron sized particles, which make up the “visible” component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. It is suggested that the extent of the E ring and the braided, kinky structure of certain portions of the F rings as well as possible time variations are a result of plasma induced electromagnetic perturbations and drag forces. The G ring, in this scenario, requires some form of shepherding and should be akin to the F ring in structure. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 102to 104years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

Recurrence Characteristics Analysis of Near-Surface Wind Speed Signal with Different Sampling Frequencies

2014 ◽  
Vol 599-601 ◽  
pp. 1605-1609 ◽  
Author(s):  
Ming Zeng ◽  
Zhan Xie Wu ◽  
Qing Hao Meng ◽  
Jing Hai Li ◽  
Shu Gen Ma
Keyword(s):  
Wind Speed ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Recurrence Plot ◽  
Sampling Frequency ◽  
Near Surface ◽  
Gas Leakage ◽  
Time Period ◽  
Characteristics Analysis ◽  
Quantification Analysis

The wind is the main factor to influence the propagation of gas in the atmosphere. Therefore, the wind signal obtained by anemometer will provide us valuable clues for searching gas leakage sources. In this paper, the Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) are applied to analyze the influence of recurrence characteristics of the wind speed time series under the condition of the same place, the same time period and with the sampling frequency of 1hz, 2hz, 4.2hz, 5hz, 8.3hz, 12.5hz and 16.7hz respectively. Research results show that when the sampling frequency is higher than 5hz, the trends of recurrence nature of different groups are basically unchanged. However, when the sampling frequency is set below 5hz, the original trend of recurrence nature is destroyed, because the recurrence characteristic curves obtained using different sampling frequencies appear cross or overlapping phenomena. The above results indicate that the anemometer will not be able to fully capture the detailed information in wind field when its sampling frequency is lower than 5hz. The recurrence characteristics analysis of the wind speed signals provides an important basis for the optimal selection of anemometer.

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