Parameterizations of some important characteristics of turbulent fluctuations and gusty wind disturbances in the atmospheric boundary layer

Abstract

[1] Parameterizations of several key characteristics of the high frequency turbulent fluctuations, the intermediate gusty wind disturbances, and their vertical profiles have been constructed with the physically based approach, and by the use of multilevel ultrasonic anemometer -thermometer observational data sets in the cold air mass. These characteristics are the kinetic energy and friction velocity of the turbulence and gust, the equivalent horizontal and vertical amplitudes and equivalent period of the gust train. The accuracy of parameterizations is statistically good (the coefficient of determination R 2 > 0.5). Some problems about their further improvement and application were also discussed in this paper. Parameterization of gusty wind disturbances separated from the high frequency turbulence is important in the models for calculation and prediction of emission and entrainment of aerosol particles in the atmospheric boundary layer, because the role of turbulence is diffusion, but gusty wind disturbances act as small scale advection to entrain particles into the upper part of the atmospheric boundary layer.

Effect of wind speed and relative humidity on atmospheric dust concentrations in semi-arid climates

“…Wind speed and relative humidity data were acquired from the PDEQ site while frequency of wind speed > 5 m/s was measured by the co-located Kestrel weather stations at each site. The frequency of high winds gives a sense of gustiness (with a consequent greater potential for particle entrainment) for the field locations while wind speed gives a sense for the event’s dust generation potential (Zeng et al, 2010; Cheng et al, 2012). Because relative humidity before and during the event is an important factor for soil moisture content, 24-hour average and event average relative humidity are compared in Figure 5.…”

Current gust forecasting techniques, developments and challenges

“…Other motivators for this development are in large scale urban engineering, where for instance the profile of wind and gust dictates the stress profile on a large building, and similarly, in forestry. Cheng et al (2012b) address the development of improved physically-based gusts parametrisations, with an emphasis on the gust profile. Suomi et al (2013Suomi et al ( , 2015Suomi et al ( , 2016Suomi et al ( , 2017 characterise gust profiles using measurements and pursue the development of gust parametrisations in this context.…”

“…Stucki et al (2016) find little difference between diagnostics when applied to a 20th century WRF model reanalysis, again over Switzerland. Interest continues in developing better physically-based gust parametrisations (Cheng et al, 2012b;Suomi et al, 2013).…”

On the upward flux of sea‐spray spume droplets in high‐wind conditions

“… is the mean vertical velocity, and w t can be obtained through equations and . The ( u g , w g ) are parameterized in the same way as in Cheng et al []: where the equivalent gust amplitudes A gi ( i = u , w ) and the equivalent period T g are also parameterized through and α g is the arcsine of the gust coherency. A gi ( i = u , w ) and T g are summarized from Cheng et al [, ] and given in Table ; their coefficients are fitted through the observations in section 2.2, and the R 2 values of the fitting are also given in Table .…”

“…A gi (i = u, w) and T g are summarized from Cheng et al [2014Cheng et al [ , 2015 and given in Table 1; their coefficients are fitted through the observations in section 2.2, and the R 2 values of the fitting are also given in Table 1. The fitting accuracy of the cold surge is better than that of typhoon, and more parameterization details can be seen in Cheng et al [2012bCheng et al [ , 2014Cheng et al [ , 2015.…”