Prediction and measurement of direct-normal solar irradiance: A closure experiment
- Brookhaven National Lab., Upton, NY (United States)
- State Univ. of New York, Albany, NY (United States)
- Hanscomb AFB (United States)
- National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
- Energy Research Inst. (Netherlands)
Direct-normal solar irradiance (DNSI), the total energy in the solar spectrum incident on a plane perpendicular to the Sun`s direction on a unit area at the earth`s surface in unit time, depends only on the atmospheric extinction of sunlight without regard to the details of extinction--whether absorption or scattering. Here the authors describe a set of closure experiments performed in north-central Oklahoma, wherein measured atmospheric composition is input to a radiative transfer model, MODTRAN-3, to predict DNSI, which is then compared to measured values. Thirty six independent comparisons are presented; the agreement between predicted and measured values falls within the combined uncertainties in the prediction (2%) and measurement (0.2%) albeit with a slight bias ({approximately} 1% overprediction) that is independent of the solar zenith angle. Thus these results establish the adequacy of current knowledge of the solar spectrum and atmospheric extinction as embodied in MODTRAN-3 for use in climate models. An important consequence is the overwhelming likelihood that the atmospheric clear-sky absorption is accurately described to within comparable uncertainties.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 537294
- Report Number(s):
- BNL-64443; CONF-970365-3; ON: DE97008262; BR: KP-120103; TRN: AHC29722%%59
- Resource Relation:
- Conference: Atmospheric research management science team meeting, San Antonio, TX (United States), 4-7 Mar 1997; Other Information: PBD: Mar 1997
- Country of Publication:
- United States
- Language:
- English
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