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Sensors and sensory systems
Published in You-Lin Xu, Jia He, Smart Civil Structures, 2017
Based on the usage of electromagnetic (EM) signals, Doppler radar wind profilers (see Figure 3.4a) can be employed to remotely sense winds aloft. Propagation of radar signals through the atmosphere is strongly dependent on local meteorological conditions, especially in the atmospheric boundary layer (Srinivasulu et al. 2006). Due to their small aperture, ultra-high-frequency (UHF) profilers operating around 900–1300 MHz are most suitable for measuring winds in the boundary layer and lower troposphere regions. Unlike the very high-frequency (VHF) wind profiling radars, UHF radars are very sensitive for hydrometeors due to the small wavelength used. With the utilisation of sound waves, the Doppler sodar wind profiler (see Figure 3.4b) is capable of measuring wind speed at various heights above the ground and the thermodynamic structure of the lower layer of the atmosphere. These sodar profilers can be categorised as mono-static systems, in which the same antenna is used for transmitting and receiving signals, and bi-static systems, in which separate antennas are used. In mono-static systems, the atmospheric scattering is caused by temperature fluctuations, whereas in bi-static systems such scattering is caused by both temperature and wind velocity fluctuations. The GPS dropsonde contains a GPS receiver, along with temperature, humidity and pressure sensors to capture thermodynamic data and atmospheric profiles. The first Omega-based dropsonde system was developed by the Atmospheric Technology Division of the National Center for Atmospheric Research (NCAR) in the early 1970s (Cole et al. 1973). In the following years, a dropsonde based on GPS satellite navigation was further developed. The NCAR GPS dropsonde represents a major advance in both accuracy and resolution for atmospheric measurements over data-sparse oceanic areas of the globe, providing wind accuracies of 0.5–2.0 m/s with a vertical resolution of 5 m (Hock and Franklin 1999).
Observed ozone over the Chesapeake Bay land-water interface: The Hart-Miller Island Pilot Project
Published in Journal of the Air & Waste Management Association, 2019
Joel Dreessen, Daniel Orozco, James Boyle, Jay Szymborski, Pius Lee, Adrian Flores, Ricardo K. Sakai
The MDE Radar Wind Profiler (RWP) at the HU-Beltsville site (Figure 1) provided near-continuous, vertical wind profile observations of the lowest 4 km of the troposphere in closer proximity to the NCB, representing the sub-regional scale during the study period. RWP data was retrieved from the MDE data archive. The RWP collected data on 17 of the 24 exceedance days at the same hour of peak ozone at HMI and was consistent with rawinsondes from IAD showing northwest flow within the PBL. Excluding the three anomalous exceedance days without southerly surface winds in the NCB, the 0.5–1.5 km layer average wind direction observed by the RWP was 286° at 9 mph. Thus, winds turned over 100° on average in the 17 days examined between the water surface and the 0.5–1.5 km layer. Even the three anomalous exceedance days had wind shear of approximately 71° on average between the surface wind and 0.5–1.5 km layer average wind.
Monitoring wind effects of a landfall typhoon on a 600 m high skyscraper
Published in Structure and Infrastructure Engineering, 2019
Qiusheng Li, Yuncheng He, Yinghou He, Kang Zhou, Xuliang Han
Besides traditional weather measurement instruments, SSP station in Hong Kong, established by HKO, is equipped with a boundary-layer-type Doppler radar wind profiler system whose detection scope covers a vertical range of 315–9223 m at 202.5 m intervals. Mean values of horizontal wind speed and direction at various height levels are computed, recorded, and qualified automatically by the logger based on instantaneous measurements over each 10-min period. The distance between SSP station to PAFC is about 25 km.