Lidar measurements and wavelet covariance transform method to estimate the atmospheric boundary layer heights in Medellín, Colombia

Abstract

The Atmospheric Boundary Layer (ABL) includes the portion of the atmosphere which is directly influenced by the presence of the Earth´s surface, and usually has much higher aerosol concentration than free troposphere above. Lidar system measures the intensity of backscattered light mainly from aerosol particles as a function of distance. Thus, the significant change in the backscatter across the top of the BL provides a means of determining ABL heights. Whereas an urban area situated in a complex mountain valley of Colombian tropical Andean region, we present the first results of estimating the height of the daytime ABL for Medellín city (Lat: 6°15' 38.37'', Long:-75° 34' 40.46'', Alt: 1483 m a.s.l.), using the wavelet covariant transform method in processing the elastic backscatter signal collected by a lidar built in Medellín city.

Strong Saharan Dust Event Detected at Lalinet LOA-UNAL Station, over Medellín, Colombia by Active and Passive Remote Sensing

“…Also, it was used a CIMEL sun photometer of NASA-AERONET which allowing us to getting direct products (AOD and AE, and inversion products such as particle size distribution and SSA, with uncertainties about 0.01 at wavelengths larger than 440 nm and about 0.02 at wavelengths shorter that this value [8]. …”

Lidar Observations in South America. Part II - Troposphere

“…Nevertheless, in most regions, the radiosondes are launched only twice a day, which does not provide a detailed observation of the ABLH behavior. In this scenario, due to the lidar systems' high temporal and spatial resolution, the utilization of this kind of equipment to estimate the ABLH and other ABL properties had increased significantly in the last decade, mainly in South America [20][21][22][23][24][25][26][27][28][29][30].…”

Pollution and its Impacts on the South American Cryosphere

“…The diurnal evolution of the boundary layer is modulated by insolation, surface winds, stratification, land use, surface roughness, topography, anthropogenic heat, synoptic, and sub-synoptic phenomena. Large urban areas are located within or near the Andes (e.g., Santiago, La Paz, Quito, and Bogota), but there are a few studies that have characterized the atmospheric boundary layer in the complex terrain close to the Andes, mostly due to the lack of vertically-resolved observations [Muñoz and Undurraga, 2010;Andrade et al, 2011;Toledo and Gustín, 2011;Muñoz et al, 2013;Nisperuza, 2014]. Current models provide sophisticated parameterizations of boundary layer processes, but their validation is limited by the lack of systematic and long-term observations at different altitudes [Freitas et al, 2006;Saide et al, 2011aSaide et al, , 2011b.…”