Seasonal statistics of the vertical distribution of wind speed at the Baikal Astrophysical Observatory

Abstract. As the unmanned aerial vehicle (UAV) technology has gained popularity over the years, it has been introduced for air quality monitoring. This study demonstrates the feasibility of customized UAV with mobile monitoring devices as an effective, flexible, and alternative means to collect three-dimensional air pollutant concentration data. This also shows the vertical distribution of PM concentration and the relationship between the PM2.5 vertical distribution and the meteorological parameters within 500m altitude on a single flight in UP Diliman, Quezon City. Measurement and mapping of the vertical distribution of particulate matter (PM)2.5 concentration is demonstrated in this research using integrated air quality sensors and customized Unmanned Aerial Vehicle. The flight covers an area with a radius of 80 meters, following a cylindrical path with 40-meter interval vertically. The PM2.5 concentration values are analyzed relative to the meteorological parameters including air speed, pressure, temperature, and relative humidity up to a 500meter-flying height in a single flight in Barangay UP Campus, UP Diliman, Quezon City. The study shows that generally, the PM2.5 concentration decreases as the height increases with an exception in the 200&ndash;280m above ground height interval due to a sudden change of atmospheric conditions at the time of the flight. Using correlation and regression analysis, the statistics shows that PM2.5 concentration has a positive relationship with temperature and a negative relationship with relative humidity and wind speed. As relative humidity and wind speed increases, PM2.5 decreases, while as temperature increases, PM2.5 also increases.

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Wind Effects for Floating Algae Dynamics in Eutrophic Lakes

Remote Sensing ◽

10.3390/rs13040800 ◽

2021 ◽

Vol 13 (4) ◽

pp. 800

Author(s):

Yuchao Zhang ◽

Steven Loiselle ◽

Kun Shi ◽

Tao Han ◽

Min Zhang ◽

...

Keyword(s):

Climate Change ◽

Wind Speed ◽

Vertical Distribution ◽

Algal Blooms ◽

Algal Bloom ◽

Lake Taihu ◽

Early Warning Systems ◽

Eutrophic Lakes ◽

Algae Blooms ◽

The Vertical Distribution

Wind-speed decline is an important impact of climate change on the eastern Asian atmospheric circulation. Although wind does not determine algae biomass in eutrophic lakes, it is a decisive factor in the formation and severity of algae blooms. Based on 2000–2018 MODIS images, this study compared the effects of wind speed on algal blooms in three typical eutrophic lakes in China: Lake Taihu, Lake Chaohu and Lake Dianchi. The results indicate that climate change has different effects on the wind speed of the three lakes, but a common effect on the vertical distribution of algae. A wind speed of 3.0 m/s was identified as the critical threshold in the vertical distribution of chlorophyll-a concentrations in the three study lakes. The basic characteristics of the periodic variation of wind speed were different, but there was a significant negative correlation between wind speed and floating algal bloom area in all three lakes. In addition, considering lake bathymetry, wind direction could be used to identify locations that were particularly susceptible to algae blooms. We estimated that algal bloom conditions will worsen in the coming decades due to the continuous decline of wind, especially in Lake Taihu, even though the provincial and national governments have made major efforts to reduce eutrophication drivers and restore lake conditions. These results suggest that early warning systems should include a wind-speed threshold of 3.0 m/s to improve control and mitigation of algal blooms on these intensively utilized lakes.

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BLOWN SAND ON BEACHES

Coastal Engineering Proceedings ◽

10.9753/icce.v18.73 ◽

1982 ◽

Vol 1 (18) ◽

pp. 73

Author(s):

Susumu Kubota ◽

Kiyoshi Horikawa ◽

Shintaro Hotta

Keyword(s):

Wind Speed ◽

Wind Tunnel ◽

Vertical Distribution ◽

Shear Velocity ◽

Wind Tunnel Experiment ◽

Transport Rate ◽

Sand Transport ◽

Sand Transport Rate ◽

Empirical Coefficients ◽

The Vertical Distribution

The blown sand transport rate and the vertical and shore-normal distributions of the wind speed were measured simultaneously on a windy beach. The sand transport rate was measured with conventional total quantity-type traps and with a large trap in the form of a trench. The vertical distribution of the wind speed was measured using an ultrasonic anemometer array consisting of six meters. The distribution of wind speed at a height of 1 m in a section normal to the shoreline was measured with five ultrasonic anemometers. A logarithmic law for the vertical distribution of the wind speed was satisfied, and the wind speed in the section normal to the shoreline was almost constant. The Kawamura and Bagnold formulae were found to predict well the sand transport rate. The trench trap and conventional traps gave empirical coefficients of 1.5 and 1.0, respectively, for the sand transport rate averaged over a section normal to the shoreline. The lower value determined with the conventional traps (1.0) is attributed to their inefficiency compared with the trench trap. In order to obtain data at high shear velocities, a wind tunnel experiment was carried out. This experiment showed that both the Kawamura and Bagnold formulae were valid in the range between 60 to 300 cm/s in the wind shear velocity. The empirical coefficient in the laboratory experiments was 1.0: the difference between the field result with the trench trap and the wind tunnel experiment is attributed to the fluctuations in natural wind.

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Dependence of the vertical distribution of bromine monoxide in the lower troposphere on meteorological factors such as wind speed and stability

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-2119-2015 ◽

2015 ◽

Vol 15 (4) ◽

pp. 2119-2137 ◽

Cited By ~ 25

Author(s):

P. K. Peterson ◽

W. R. Simpson ◽

K. A. Pratt ◽

P. B. Shepson ◽

U. Frieß ◽

...

Keyword(s):

Wind Speed ◽

Vertical Distribution ◽

Degrees Of Freedom ◽

Atmospheric Stability ◽

Lower Troposphere ◽

Optimal Estimation ◽

Vertical Column ◽

Vertical Column Density ◽

Halogen Activation ◽

The Vertical Distribution

Abstract. Multiple axis differential absorption spectroscopy (MAX-DOAS) measurements of bromine monoxide (BrO) probed the vertical structure of halogen activation events during March–May 2012 at Barrow, Alaska. An analysis of the BrO averaging kernels and degrees of freedom obtained by optimal-estimation-based inversions from raw MAX-DOAS measurements reveals the information is best represented by reducing the retrieved BrO profile to two quantities: the integrated column from the surface through 200 m (VCD200 m), and the lower tropospheric vertical column density (LT-VCD), which represents the integrated column of BrO from the surface through 2 km. The percentage of lower tropospheric BrO in the lowest 200 m was found to be highly variable ranging from shallow layer events, where BrO is present primarily in the lowest 200 m, to distributed column events where BrO is observed at higher altitudes. The highest observed LT-VCD events occurred when BrO was distributed throughout the lower troposphere, rather than concentrated near the surface. Atmospheric stability in the lowest 200 m influenced the percentage of LT-VCD that is in the lowest 200 m, with inverted temperature structures having a first-to-third quartile range (Q1–Q3) of VCD200 m/LT-VCD from 15–39%, while near-neutral-temperature structures had a Q1–Q3 range of 7–13%. Data from this campaign show no clear influence of wind speed on either lower tropospheric bromine activation (LT-VCD) or the vertical distribution of BrO, while examination of seasonal trends and the temperature dependence of the vertical distribution supported the conclusion that the atmospheric stability affects the vertical distribution of BrO.

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