Updating the davenport roughness classification best online dating apps 2018 election

Experiments based on ALOS PALSAR and COSMO-Sky Med data from 2006 to 2011 prove that the proposed methodology can provide accurate roughness length estimations for the spatial and temporal analysis of urban surface.

Urban areas occupy only a very small fraction of the Earth’s land area, yet 60–80% of final energy and concentrate materials, wealth, and innovation is consumed in urban areas.

And then the optimal dimension of the upwind sector for the aerodynamic roughness calculation was determined through a correlation analysis between backscattering extracted from SAR data at various upwind sector areas and the aerodynamic roughness calculated from the meteorological tower data.

Finally a quantitative relationship was set up to retrieve the aerodynamic roughness length from SAR data.

Aimed at addressing these limitations, this paper proposed an aerodynamic roughness estimation methodology from SAR data based on a precise scale and orientation analysis, where ground truth aerodynamic roughness values were calculated using meteorological tower data.

First, the scale and orientation characteristics of backscattering of roughness elements in urban areas were thoroughly analyzed.

Stetson estimated the aerodynamic roughness length in Houston metropolitan area through applying a coefficient to the commonly used roughness length of a given class, which was determined according to the quotient of a pixel’s backscattering and the mean backscattering of the corresponding land use type [10]. used multitemporal SAR images for supervised classification and then mapped the urban aerodynamic roughness using a look-up table for each land use class [11].

This is the most widely used method, yet it is not suitable for mesoscale models because urban areas need more precise classification results and yet it is very difficult because urban areas are highly heterogeneous.

And experiments showed that this method could provide roughness parameters acceptable for meteorological models. defined grid cells ranging in size from 25 to 250 m for correlation analysis between SAR data and urban roughness but did not consider aerodynamic roughness in heterogeneous urban areas is highly related to the roughness elements in the upwind area and the scale and orientation sensitivity analysis is indispensable.

With rapid urbanization, the population of urban areas has exceeded rural areas in the past decade [1].

The increased amount of roughness elements, which are mainly composed of buildings and road networks in urban areas, dramatically alters the surface roughness and urban boundary layer dynamics [2], which in turn results in more frequent air pollution and extreme weather.

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Aerodynamic roughness is very important to urban meteorological and climate studies.

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