Aerosol extinction hygroscopic growth is one of the important parameters to characterize the hygroscopic properties of aerosols, as well as explore the environmental effects of aerosols and evaluate air quality. In this paper, the variation characteristics of aerosol extinction factor, atmospheric visibility (VIS) and relative humidity (RH) were analyzed based on the measurements in Hefei during winter (from December 2021 to January 2022). It is shown that the aerosol extinction coefficient (VIS) is positively (negatively) correlated with RH, especially in high-RH environments where the extinction coefficient (VIS) is extremely high (extremely low). Based on four commonly used empirical parameterization schemes of aerosol extinction hygroscopic growth factor, an empirical model of aerosol extinction hygroscopic growth factor for winter in Hefei is presented. There is no significant difference in the parameterization results of the four models, which are able to express the variation characteristics of aerosol extinction hygroscopic growth with RH, but the simulations of the four models are higher than the observations in high-RH environment.
This paper present the diurnal and seasonal variation of Turbulence Kinetic Energy (TKE) dissipation rate ( Ε ) in the Atmospheric Boundary-Layer (ABL) in Hefei area. Doppler spectrum width of wind profiler radar are used to separate the non-turbulent spectral width from the observed spectrum width and estimate ε .It is found that in the lower tropospheric height ε is in the range from 10-6 to 10-3 m2 s-3 . ε showed significant diurnal variation in the boundary-layer, with a smaller value at night and a larger value during the day, and the maximum value 10-3 m2 s-3 appears at the top of the ABL during the daytime. The diurnal variation of ε can be used to demonstrate the change of the boundary-layer height in Hefei area. The boundary-layer height begins to rise after sunrise and reaches the maximum at noon, about 1200 m. The parameter ε also shows significant seasonal variation. The ε and height of boundary-layer increased gradually since spring, reaching a maximum of about 1.3km in autumn and decreasing to the same level as in spring in winter. Because it is not affected by water vapor and temperature, ε from the data inversion of wind profile radar can describe turbulence information more accurately, and the results provide help for the study of matter and energy exchange between earth and air in Hefei area and laser atmospheric transmission etc.
As the "roof of the world", the Tibetan Plateau (TP, in short) exhibits the distinctive "heat island" characteristics compared to the same latitude region, and plays a decisive role in the atmospheric thermal structure of the TP and surroundings. ERA5 reanalysis data from January 2017 to December 2020 are used to analyze the meridional distribution characteristics of the average skin temperature and the potential temperature lapse rate at coldest point tropopause (CPT) in the highaltitude areas of the TP in summer. The Pearson correlation coefficient between the measured data and the reanalyzed data in the Da Qaidam area (95°21’E, 37° 51’N, 3180m above sea level (ASL)) in August 2020 is 0.88, indicating good usability of the reanalyzed data. The average skin temperature of TP in summer shows a feature of "high in the south and low in the north", which is ~20° higher than the atmospheric temperature of surrounding low-altitude area at the same altitude. The distribution of heat sources on the TP not only affects the location and intensity of the South Asian High, but also aggravates the thermal difference between land and sea, which promotes the formation of the Asian summer monsoon. The strong heat source in the southern TP, on the one hand, directly affects the atmospheric thermal structure over the southern TP through enhancing upward transportation; on the other hand, indirectly affects the high-altitude atmospheric thermal structure of the region north to TP through the background transportation of westerly and summer monsoons. The potential temperature lapse rate at CPT over the high-altitude area of TP also has significant characteristics of north-south differences, indicating that the "heat source effect" can regulate the intensity of atmospheric turbulence.
Atmospheric stability characterizes the intensity of vertical movement near the ground. Monin- Obukhov length is the most commonly used also most important stability parameter in boundary layer theory, which can be calculated by the dimensional analysis method on the basis of the similarity theory of the near-surface layer. The M-O parameter ζ is often used to characterize the stability (the ratio of height to M-O length). When the atmospheric stratification is neutral, ζ=0; when the atmospheric stratification is stable, ζ>0, and the larger the value, the more stable the atmosphere; When the atmosphere stratification is unstable, ζ<0, and the smaller the value, the more unstable the atmosphere. Using the three-dimensional wind speed data of the ship-borne three-dimensional ultrasonic anemometer and the meteorological data observed by the automatic weather station, combined with similar theory, to analyze the atmospheric stability parameter ζ above the sea surface. The results show that the atmospheric stability has an obvious diurnal variation trend, the night atmosphere is mostly stable, and the atmospheric turbulence is vigorous at noon. Besides, using three-dimensional ultrasonic wind speed data combined with virtual temperature correction, the atmospheric refractive index structure constant is calculated and compared with the measured value of the micro-thermal meter. This paper also analyzes the values of friction velocity 𝒖𝒖∗, characteristic temperature 𝑻𝑻∗ , characteristic humidity 𝑸𝑸∗ and atmospheric refractive index structure constant Cn2 under different stability conditions to understand the changing characteristics of optical turbulence on the underlying surface of the ocean.
As an important part of the atmospheric environment, aerosols play a critical role in the study of the relationship between light and radiation. However, due to the complex spatiotemporal distribution of aerosols, it is much difficult to measure their microphysical properties and to determine their optical properties in coastal areas. In this paper, basic meteorological elements (e.g., wind speed, temperature, humidity) are simulated with the numerical weather forecasting (WRF) model. Then, the coastal aerosol model (CAM) together with the observation data is used to simulate the aerosol particle size distribution (APSD) and extinction coefficient for the coastal environment of Qingdao. Finally, data measured by the automatic weather station and particle counter in the coastal area are compared to their corresponding simulations. According to the comparisons results, temperature simulations were higher from an overall perspective (<2°C) with the correlation coefficient larger than 0.96; humidity simulations were comparatively lower on the 11th and 12th day (<10%) than those onthe 13th day (<20%), but the correlation coefficient was still larger than 0.8. With the meterological parameters simulations, the CAM model was used to predict the APSDs. It is founded that simulations for large particles are generally larger, while those for giant particles are generally smaller, but the simulated temperature, humidity, APSD and extinction coefficient are very consistent with their corresponding measurements. The method established in this paper is promising for the simulation and forecast of both the meteorological elements and aerosol microphysical properties.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.