Đặc điểm độ dày quang học sol khí từ số liệu các trạm AERONET Mở đầu Sol khí (aerosol) bao gồm các hạt rắn, lỏng tồn tại lơ lửng trong khí quyển, là một trong những tác nhân quan trọng gây nên biến đổi tính chất quang học, hóa học khí quyển, chúng tác động tới quá trình hình thành mây, tán xạ và hấp thụ năng lượng  Tác giả liên hệ, Email: pxthanh@igp-vast.vn bức xạ, gây nên những biến đổi trong hệ thống thời tiết -khí hậu. Các phần tử sol khí tán xạ và hấp thụ bức xạ làm cho lớp khí quyển ấm lên và bề mặt trái đất lạnh đi, ảnh hưởng trực tiếp đến khí hậu (Kaufman et al., 2002, Lau et al., 2008, Mielonen et al., 2011, Qi YuLei và nnk, 2013. Ngoài ra, sol khí ảnh hưởng gián tiếp đến khi hậu do các phần tử sol khí làm tăng số hạt nhân ngưng kết,

In this study, the WRF (Weather Research and Forecasting) model was used to simulate and investigate diurnal and annual variations of wind speed and wind power density over Southern Vietnam at 2‐km horizontal resolution for two years (2016 and 2017). The model initial and boundary conditions are from the National Centers for Environmental Prediction (NCEP) Final Analyses (FNL). Observation data for two years at 20 m height at Bac Lieu station were used for model bias correction and investigating diurnal and annual variation of wind speeds. The results show that the WRF model overestimates wind speeds. After bias correction, the model reasonably well simulates wind speeds over the research area. Wind speed and wind power density show much higher values at levels of 50–200 m above ground levels than near ground (20 m) level and significantly higher near the coastal regions than inland. Wind speed has significant annual and diurnal cycles. Both annual and diurnal cycles of wind speeds were well simulated by the model. Wind speed is much stronger during daytime than at nighttime. Low-level wind speed reaches the maximum at about 14 LT to 15 LT when the vertical momentum mixing is highly active. Wind speeds over the eastern coastal region of Southern Vietnam are much stronger in winter than in summer due to two main reasons, including (1) stronger large-scale wind speed in winter than in summer and (2) funnel effect creating a local maximum wind speed over the nearshore ocean which then transports high-momentum air inland in winter.

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In this paper, the characteristics of wind speed at 20 m height at the Bac Lieu atmospheric physic station (Bac Lieu station) in 2016 were evaluated using the Weibull distribution function. The wind speed data set (every minute) from January 7th  to December 31st, 2016 was used to calculate the two parameters of  Weibull function including Weibull shape factor “k” and Weibull scale factor “c”. The results showed that at the Bac Lieu station in 2016, the values of k and c were 1.69 and 3.91, respectively. Some characteristics of wind speed were also estimated such as wind energy density (Pa/A=57.3 W/m2), wind speed of maximum energy carrier (Vmec=6.2 m/s), the most probable wind speed (Vmp=2.3 m/s), mean wind speed (Vmean­=3.5 m/s)  and standard deviation of wind speeds (s = 2.1 m/s).

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