Satellite Mapping of the Surface Radiation Budget

Abstract

Bioclimatology is defined in the preface to Advances in Bioclimatology as "the study of the relations between the physical environment and the form and function ofliving organisms". Such a definition largely confines the discipline to the proximity of the land surface, the interface between the atmospheric boundary layer, vegetation and the soil surface.. Physical climatology is concerned with the processes by which energy and mass are transferred, converted and stored in the Earth-atmosphere system (Oke 1988). The transfer of energy occurs in three modes: conduction, convection and radiation. Radiation is the transfer of energy by the rapid oscillations of electromagnetic fields. These oscillations may be considered as travelling waves, characterized by wavelength A. In environmental physics and bioclimatologywe are concerned with wavelengths in the approximate range ofO.001-100/-lm (l/-lm = 10-6 m = 1000 nm = 10 4 A).Solar radiation is the sole source of energy to living organisms, directly in the case of plants and indirectly to animals -including man. All physical and biological processes at and near the land surface are driven by energy from the sun. Shortwave radiation falls in the 0.15-3 /-lm range and longwave radiation lies in the range 3-100/-lm. Ultraviolet (UV) radiation has wavelengths between 0.001 and OA/-lm, i.e., 1-400nm. UV-C radiation (A < 280nm) never reaches the Earth's surface because of absorption by the atmosphere; the 280-320nm range is called UV-B; and UV-A comprises the 320-400nm part of the spectrum. UV-A and UV-B radiation is of major significance for human health and plays a role in biological productivity.All processes, including the biological, involve energy transformation or transfer. The energy balance describes the energy available to land-surface processes and how this energy is used. Sellers (l965) observes that "the physical state of any entity, from a small leaf to a whole continent is determined by the way it utilizes the available energy". The radiation and energy balances are

Estimating Land Surface Evaporation: A Review of Methods Using Remotely Sensed Surface Temperature Data

“…Readers are referred to Sellers et al (1990); Schmugge and Becker (1991); Zhang et al (1995); Nunez and Kalma (1995); Boegh et al (1999) and Bisht et al (2005) for reviews of the use of remotely sensing data for estimating components of the radiation budget and hence R n . Bisht et al (2005) expressed concern about the risk of error accumulation; for example, when estimating net long wave radiation the upward and downward longwave radiation fluxes are both large components, so differences between these components may be prone to significant uncertainty.…”

A comparison of cloudless sky erythemal ultraviolet radiation at two sites in southwest Sweden

“…For cloudless conditions, broadband radiation is reacting not only to aerosols, but to total column water vapour and carbon dioxide as well as other minor constituents of the atmosphere (Iqbal, 1983). Absorption by water vapour and other gases can be large in tropical atmospheres, but temperate mid-latitude locations will exhibit lower absorptivities and smaller day-to day variations (Nunez and Kalma, 1996). Therefore it was decided to examine broadband solar radiation as an index of turbidity to accompany the ultraviolet radiation measurements.…”

Hourly global irradiance from satellite data in Badajoz, Spain: Spatial and temporal dependence

“…Pyranometer stations are infrequent in most regions of the world so that techniques which relate satellite reflectance to cloud opacity are used to calculate surface solar irradiance. The technique has been used for over two decades, and the reader is referred to reviews by Schmetz [], Sellers et al [], Hay [], and Nunez and Kalma [] among others. Techniques vary although they are strongly related to the treatment of satellite‐derived cloud reflectance.…”