Glossary of Solar Radiation Resource Terms

Other relevant glossaries


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Macroclimate - the general climate of a large region such as the Rocky Mountains or the Northern Great Plains.


Megawatt - a unit of power equal to 1,000,000 (106) Watts.


Measurement Uncertainty - the bounds that should be placed on a measured value because of uncertainties in the measurement. If there are several factors pertaining to the measurement, such as voltage bias and temperature bias and precision of measurement scale, the total measurement uncertainty can be difficult to calculate and may be larger than the largest individual uncertainty of any one factor depending on the sensitivity of the measurement to the significant factors. There is no such thing as a perfect measurement, although some measurements are so precise that errors are negligible. Solar irradiance measurements are notoriously unreliable with the best methods (1% to 3% uncertainty, which means that an "excellent" method can produce results that may differ as much as 50 W/m2), and can become worthless (10% to 30% uncertainty) with careless methods.


Mesoclimate - the climate that is peculiar to a small natural feature such as a hill or a small lake. This climate tends to be different from the general climate of the region in predictable ways. Statements such as "it always rains more in Hunter's Glen in the spring" or "it snows more at the airport than downtown" are statements about mesoclimates.


Meteorology - the study of the atmosphere.


METSTAT - the METeorological/STATistical solar irradiance model developed to produce the 1961-1990 National Solar Radiation Data Base. METSTAT uses meteorological inputs such as cloud cover and precipitable water to produce a nominal value of solar irradiance, and randomly varies this value via statistical tables derived from measured solar irradiance data. METSTAT produces hourly solar irradiance data sets that are intended to behave like observed data, although the randomizer tends to guarantee that there will not be an hour-by-hour match of measured data to METSTAT-derived data.


Microclimate - the local climate near the ground that is peculiar to a small area (usually, the radius is less than a kilometer, and can be as small as a centimeter). A microclimate region is defined by changes in behavior of the atmosphere's surface boundary layer and not by obvious physical features.


Mie Scattering - the scattering of solar radiation by (mathematically spherical) particles in the atmosphere which have an approximate size of the wavelength of light, analyzed by Gustav Mie. While Rayleigh scattering explains the blue sky, Mie scattering explains why wet, coastal skies are whiter than dry, mountainous skies.


Minutes of Sunshine - a specific instance of bright sunshine duration, the number of minutes per hour during which the sun casts an obvious shadow or when a Campbell-Stokes sunshine recorder is recording, usually above 210 W/m2.


Model - a way to represent a system for the purposes of reproducing, simplifying, analyzing, or understanding it. The standard representation in the Renewable Resource Data Center is the computer model, but models can be made of any substance such as clay, paper, abstract mathematics, or concepts.


The following links allow you to move to the words beginning with that letter.

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