The urban boundary layer (UBL), in comparison with ‘rural’ homogeneous PBLs, is characterised by greatly enhanced mixing, resulting from both the large surface roughness and increased surface heating, and by horizontal inhomogeneity of the mixing height (MH) and other meteorological fields due to variations in surface roughness and heating from rural to central city areas. So, it is reasonable ...

The laminar-to-turbulent transition of boundary layers induced by isolated threedimensional roughness elements is analyzed by mining a direct numerical simulation database, which covers the variation of many physical parameters, including Mach and Reynolds numbers, and obstacle shape and size. We find that the transition process is approximately controlled by a Reynolds number based on the mome...

Topographic variation underpins a myriad of patterns and processes in hydrology, climatology, geography and ecology and is key to understanding the variation of life on the planet. A fully standardized and global multivariate product of different terrain features has the potential to support many large-scale research applications, however to date, such datasets are unavailable. Here we used the...

This work describes a mathematical representation of terrain data consisting of a novel operation, the “drill”. It facilitates the representation of all legal terrains, capturing the richness of the physics of the terrain’s generation by digging channels in the surface. Given our current reliance on digital map data, hand-held devices, and GPS navigation systems, the accuracy and compactness of...

The VV-polarized W-band backscattering behavior of homogeneous ground clutter has been investigated by measuring the radar cross section per unit area of 1/16th scale rough surface terrain in a 1.56 THz compact radar range. An array of scale model ground planes was fabricated with the appropriate roughness to model smooth to rough soil terrain. In addition to studying the backscattering behavio...

The EO Propagation objectives are: 1) investigate, develop and evaluate fine and coarse mode aerosol models and their effects on visibility and target detection in visible and IR wavelengths 2) Integrate and develop simple, realistic extinction, scintillation and refractivity models for infrared propagation near the ocean surface, 3) develop and evaluate advanced marine radiance models that are...