Hourly Solar and Meteorological Data (SOLMET)

SOLMET Hourly Solar Radiation and Meteorological Surface Observations is historical data set DSI-9724 archived at the National Climatic Data Center (NCDC). SOLMET was designed to provide the solar energy users with easy access to all appropriate historical meteorological data. The major parameters which make up this file are solar time, local standard time, extra terrestrial radiation, direct radiation, diffuse radiation, net radiation, global radiation on a tilted surface, global radiation on a horizontal surface- (observed data), (engineering corrected data), (standard year corrected data), additional radiation measurements, minutes of sunshine, sky conditions, visibility, weather, pressure, temperature, wind, clouds, and snow cover indicator. The salient features of SOLMET are that it: 1. Merged all available insulation and meteorological data into a single source. 2. Presented all data in the International System of Units (SI). 3. Provided time information so users could access the information in true solar and/or standard time. The time of the meteorological observation is also indicated so that the user would be aware of the meteorological observation that has been selected that is closest to the time of the solar observation; i.e., selected to be the observation nearest to the midpoint of the solar hour. Provision has also been made to handle data that are recorded in local standard time for conversion to solar time. 4. Allowed for additional solar radiation parameters (such as direct and tilted, normal incidence, diffuse, net) that was allowed to be available from stations in the future. Allowance was also made in supplemental fields for additional measurements; i.e., ultraviolet, spectral, etc. 5. Converted all historical solar radiation data (including the extraterrestrial radiation field) to the same international scale based on the same solar constant. 6. Eliminated undesirable format features that were inherent in the past data sources such as over punches, blanks, etc. 7. Coded missing observations and those observations that were estimated via models (e.g., sunshine and cloud regression models). 8. Provided global solar radiation data as they were originally observed and provided the user with data corrected for all known scale, instrument, and calibration problems in addition to a data set corrected via a model. Hourly solar radiation data is combined with hourly surface meteorological data for surface stations. Variables included: Extra-terrestrial radiation; direct, diffuse, net and tilted radiation; global radiation, minutes of sunshine, ceiling height, sky condition, visibility, weather occurrence, sea level pressure, station pressure, dry bulb temperature, dew point temperature, wind direction, wind speed, layered cloud data, snow cover.