Sea breeze

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

Sea–land breeze in a coastal city and its effect on pollen transport

Abstract: This paper presents a statistical study of the sea-land breeze in Mar del Plata (Argentina) to characterize the periods of the year when the breeze affects pollen transport, particularly the dispersion of airborne Poaceae pollen between urban and rural areas. In order to analyse the sea breeze circulation, hourly data from coastal, urban and rural meteorological stations were used. The effect of the sea breeze on the particulate matter was analysed from syncronic hourly airborne pollen records from an urban and a rural area. A sea-land breeze appeared between spring and early autumn in the hours of greatest diurnal warming. Results showed that the surface wind direction most probably associated with this phenomenon is NE and E, the time of occurrence shifting to new directions following the counterclockwise rotation, according to theoretical models for the Southern Hemisphere. Poaceae emission takes place in the morning, during the hours of maximum insolation. However, after the occurrence of the breeze, a rise in pollen concentration between 2000 hours and 0200 hours is detected because of pollen reentrainment brought about by air recirculation. The results showed that breeze transport brings a regional component to pollen assemblage.

Interacting multi-scale wind systems within an Alpine basin, Lake Tekapo, New Zealand

Abstract: The wind regime of the Lake Tekapo Basin is examined with reference to the interaction of multi-scale local, regional and synoptic circulations. Analysis of the historical wind direction record from Mt John identifies airflow from three principal directions to most frequently affect the study area. Both seasonal and diurnal trends in the frequency of each directional category are identified, which reflect the influence of local thermal forcings and seasonal changes in synoptic circulation on the Lake Tekapo windfield. Meteorological observations from a network of automatic weather stations and anemographs within the study area identified Lake Tekapo to generate its own circulation system, a lake/land breeze. This combines with the larger scale valley wind, which during ideal conditions continues after sunset in the upper reaches of the lake catchment. During light to moderate foehn northwesterly conditions, the combined lake breeze/valley wind system remains decoupled from the prevailing synoptic airstream. Towards evening when local thermal circulations weakened, a channelised foehn airstream often becomes dominant over the entire field area. Observations made during this investigation have a number of applied implications with respect to air pollution dispersion modelling and forecasting within alpine lake basins.

Coupling of convection and circulation at various resolutions

Abstract: A correct representation of the coupling between convection and circulation constitutes a prerequisite for a correct representation of precipitation at all scales. In this study, the coupling between convection and a sea breeze is investigated across three main resolutions: large-eddy resolution where convection is fully explicit, convection-permitting resolution where convection is partly explicit and coarse resolution where convection is parameterised. The considered models are the UCLA-LES, COSMO and ICON. Despite the use of prescribed surface fluxes, comparison of the simulations reveals that typical biases associated with a misrepresentation of convection at convection-permitting and coarser resolutions significantly alter the characteristics of the sea breeze. The coarse-resolution simulations integrated without convective parameterisation and the convection-permitting simulations simulate a too slow propagation of the breeze front as compared to the large-eddy simulations. From the various factors affecting the propagation, a delayed onset and intensification of cold pools primarily explains the differences. This is a direct consequence of a delayed development of convection when the grid spacing is coarsened. Scaling the time the sea breeze reaches the centre of the land patch by the time precipitation exceeds 2 mm day −1 , used as a measure for significant evaporation, yields a collapse of the simulations onto a simple linear relationship although subtle differences remain due to the use of different turbulence and microphysical schemes. Turning on the convection scheme significantly disrupts the propagation of the sea breeze due to a misrepresented timing (too early triggering) and magnitude (too strong precipitation evaporation in one of the tested convection schemes) of the convective processes. Keywords: thermally induced mesoscale circulation, precipitation, sea breeze, convection-permitting, convective parameterisations, large-eddy simulations (Published: 18 March 2015) Citation: Tellus A 2015, 67, 26678, http://dx.doi.org/10.3402/tellusa.v67.26678

Diurnal Wind, Relative Humidity and Temperature Variation in the Stellenbosch-Groot Drakenstein Wine-Growing Area

Abstract: Numerical simulations were performed for 2000-02-03 and 2000-02-04 over the Western Cape in order to observe the alternating sea and land breeze circulation and its effects on diurnal relative humidity and temperature variation, as well as to identify wine-growing areas characterised by high humidity and cool temperature during the maturation period. The Regional Atmospheric Modelling System (RAMS version 4.3) was used at a 1 km resolution. The study domain for the simulation covered a small area from False Bay up to 35 km from the coast. Results are presented using horizontal cross-sections at surface level as well as two south-north cross-sections at longitudes l8°40'E and l8°47'E in order to examine vertical profiles of the atmosphere above the Stellenbosch I Groot Drakenstein winegrowing area. Modelled results agreed with observed data in the vineyards. The sea breeze penetrated at least 35 km inland, but the cooling effect declined rapidly with distance from the sea. Temperature differences between southern and northern slopes near the sea could be significant enough to be important for viticulture.