Avoid tearing. where When a light beam encounters a material, radiation can be absorbed or reflected by the surface. La MaMa, Theater for the New City Get White Roofs", "Energy impacts of heat island reduction strategies in the Greater Toronto Area, Canada", https://en.wikipedia.org/w/index.php?title=Reflective_surfaces_(climate_engineering)&oldid=985612847, Articles with unsourced statements from February 2014, Articles with unsourced statements from December 2011, Creative Commons Attribution-ShareAlike License, Donald Bren School of Environmental Science & Management, Travaux Public et Services Gouvernementaux Canada, National Geographic Society Headquarters Complex, Salt Lake City Olympic Winter Games 2002 Organizing Committee, Premier Automotive Group North American Headquarters, Savings of up to 15% the annual air-conditioning energy use of a single-story building, This page was last edited on 26 October 2020, at 22:40. [43] LBNL found that, compared to the original black rubber roofing membrane on the Texas retail building studied, a retrofitted vinyl membrane delivered an average decrease of 24 °C (75.2 °F) in surface temperature, an 11% decrease in aggregate air conditioning energy consumption, and a corresponding 14% drop in peak hour demand. [38] In interferometry the illumination is split up into two beams by a partially reflective mirror. Since the refractive index of the ionosphere (a plasma), is less than unity, electromagnetic waves propagating through the plasma are bent "away from the normal" (see Geometric optics) allowing the radio wave to be refracted back toward earth, thus enabling long-distance radio communications. These assumptions can break down in different ways, to be described in the following subsections. [14], A 2012 study by researchers at Concordia University included variables similar to those used in the Stanford study (e.g., cloud responses) and estimated that worldwide deployment of cool roofs and pavements in cities would generate a global cooling effect equivalent to offsetting up to 150 gigatonnes of carbon dioxide emissions – enough to take every car in the world off the road for 50 years. [1]:203 Some common mirages are caused by a spatially varying refractive index of air. As many as 10 points may be awarded for 1–100 percent roof coverage with either vegetation or highly reflective materials or both. The light wave traveling in the medium is the macroscopic superposition (sum) of all such contributions in the material: the original wave plus the waves radiated by all the moving charges. is the vacuum wave impedance, μ and ϵ are the absolute permeability and permittivity of the medium, εr is the material's relative permittivity, and μr is its relative permeability. Page was last modified 23:57, 23 October 2020. If there is no angle θ2 fulfilling Snell's law, i.e., the light cannot be transmitted and will instead undergo total internal reflection. . The phase cannot be measured directly at optical or higher frequencies, and therefore needs to be converted into intensity by interference with a reference beam. [30], This tool was the collaboration of both Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory in order to provide industry-consensus roof savings for both residential and commercial buildings. However, at higher frequencies (such as visible light), dielectric loss may increase absorption significantly, reducing the material's transparency to these frequencies.