Sea breeze

About: Sea breeze is a research topic. Over the lifetime, 2544 publications have been published within this topic receiving 55651 citations.

Numerical simulation for the coupling effect of local atmospheric circulations over the area of Beijing, Tianjin and Hebei Province

Abstract: Using the model system MM5.V3 and multi-layer grid nesting technique, we have done a multi-scale numerical simulation over the area of Beijing, Tianjin and Hebei Province to analyze the temperature and wind field there and study its local circulations. The results show a coupling effect of Urban Heat Island Circulation (UHIC), Mountain Valley Breeze (MVB) and Sea Land Breeze (SLB) occurs in this area when the synoptic system is weak. The SLB can penetrate deep into the mainland for about 200 km when it is blooming. MVB can extend to south and cover almost the whole plain area in Beijing. Both MVB and SLB are diurnal periodical; meanwhile the phase of MVB drops behind that of SLB for about six hours. As a local circulation, the UHIC weakens the two circulations above, and it also has a diurnal period. As a result, the coupling effect of circulations reveals not only different features in spring-summer period and autumn-winter period in a year but also the difference between early morning to noonday and afternoon to night in a day. We noted the diffusion of contamination over the area around Beijing, and found the steady presence of a transport routine of contamination over North-China throughout the year caused by the Coupling Effect mentioned above. This find is important for studying the environment pollution in this area.

Lake‐induced atmospheric circulations during BOREAS

Abstract: Lake-induced atmospheric circulations over three lakes ranging from 3 to 10 km width are analyzed using data from three aircraft during the 1994 Boreal Ecosystem-Atmosphere Study (BOREAS). A well-defined divergent lake breeze circulation is observed over all three lakes during the day. Under light wind conditions, the lake breeze is not very sensitive to the water temperature, and the strength of the divergence over the lake decreases with increasing lake size. The boundary-layer development over the surrounding land can be very important for generating a horizontal pressure difference which drives the lake breeze. Diurnal and seasonal variations of lake breezes are investigated on the basis of repeated passes from the different aircraft at different altitudes from late spring to early fall of 1994. The lake breeze divergence increases with time during the day and reaches a maximum around 1300 LST. The latent heat flux over 10-km-wide Candle Lake increases steadily from spring to fall as the lake temperature increases. The latent heat flux over the land reaches a maximum during the summer due to evapotranspiration. The lake effect on area-averaged fluxes sometimes leads to a negative heat transfer coefficient for an averaging scale of several times the lake width.

Multiscale modeling of air pollutants dynamics in the northwestern Mediterranean basin during a typical summertime episode

Abstract: [1] The complex behavior of photochemical pollutants in the northwestern Mediterranean basin (NWMB) is conditioned by the superposition of circulations of different scale and the pattern of emissions. Therefore a new approach to the modeling of air quality in the NWMB has been adopted by combining the global climate-chemistry model ECHAM5/MESSy and the regional modeling system MM5-EMICAT2000-CMAQ to analyze the high levels of photochemical air pollution during a typical summertime episode. We show that this combination of models is well suited to address the range of scales involved. The complexity of the area requires the application of high spatial and temporal resolution (2 km and 1 hour) modeling to cover local to regional interactions. We address the local and large-scale processes controlling tropospheric ozone in the NWMB, notably emissions and photochemistry, convective and advective transport, deposition processes, and stratosphere-troposphere exchange. The simulation results indicate that the ozone buildup largely results from local photochemical production, which strongly exceeds the removal rates through transport and deposition. The contribution by advective transport is limited, associated with the stagnant meteorological conditions. In the lower troposphere, local recirculation systems are of key importance. The strength of the land-sea breeze circulation and thermally or mechanically driven convection over the complex orography of the eastern Iberian coast can induce vertical transport and the layering of air pollution.