These daily weather records were compiled from a subset of stations in the Global Historical Climatological Network (GHCN)-Daily dataset. A weather record is considered broken if the value exceeds the maximum (or minimum) value recorded for an eligible station. A weather record is considered tied if the value is the same as the maximum (or minimum) value recorded for an eligible station. Daily weather parameters include Highest Min/Max Temperature, Lowest Min/Max Temperature, Highest Precipitation, Highest Snowfall and Highest Snow Depth. All stations meet defined eligibility criteria.

The National Weather Service (NWS) periodically conducts sensor comparison studies to ensure that proposed observing equipment meets requirements set forth in specific solicitations. Other comparison studies may occasionally be conducted in support of a specific project or request, the requirements for which provide the evaluation criteria. The final result of these studies, along with the test data, is usually a summary report documenting the suitability and performance of the selected sensor(s) based on criteria established in the acquisition specification.

*Note: This dataset version has been superseded by a newer version. It is highly recommended that users access the current version. Users should only use this version for special cases, such as reproducing studies that used this version.* The Pathfinder Atmospheres - Extended (PATMOS-x) Reflectance data contain derived atmospheric variables from the Advanced Very High Resolution Radiometer (AVHRR) Global Area Coverage (GAC) data observed from three decades of the NOAA Polar-orbiting Operational Environmental Satellite (POES) series.

The Global Ensemble Forecast System (GEFS) is a weather forecast model made up of 21 separate forecasts, or ensemble members. The National Centers for Environmental Prediction (NCEP) started the GEFS to address the nature of uncertainty in weather observations, which are used to initialize weather forecast models. The proverbial butterfly flapping her wings can have a cascading effect leading to wind gusts thousands of miles away.

This publication contains hourly precipitation amounts obtained from recording rain gages located at National Weather Service, Federal Aviation Administration, and cooperative observer stations. Published data are displayed in inches to tenths or inches to hundredths at local standard time. HPD includes maximum precipitation for nine (9) time periods from 15 minutes to 24 hours, for selected stations. Hourly Precipitation Data publication period of record begins October 1951.

Radiation measurements at SURFRAD stations cover the range of the electromagnetic spectrum that affects the earth/atmosphere system. Direct solar radiation is monitored with a Normal Incidence Pyrheliometer (or NIP) mounted on the solar tracker. Downwelling global solar radiation is measured by an upward-viewing broadband pyranometer. The diffuse, or sky component, of solar radiation is measured by a shaded Eppley 8-48 pyranometer mounted on a platform that is attached to the solar tracker.

In order to fill in the observation gap prior to the time when commercial aviation began in the U.S., The NCDC Climate Data Modernization Program (CDMP) retrieved surface observations taken two to four times daily beginning as early as 1893 at the City Weather Bureau Offices. Through 1936 observations were taken twice daily; then in 1937 the general practice was to record four observations per day.

The Enhanced Master Station History Report (EMSHR) is a compiled list of basic, historical information for every station in the station history database, beginning in the 1700s through the present. The Enhanced MSHR version contains similar data elements and is in a similar format as the Standard/Legacy MSHR (DSI-9767_01), but the Enhanced MSHR includes additional stations that are included in the Global Historical Climatology Network (GHCN)-Daily product. Also, the Enhanced MSHR incorporates additional station networks, including international stations/networks.

The EXIS Instrument Engineering Telemetry Data file contains data used to support the generation of EUVS and XRS Level 1b products, and monitor and evaluate the health and performance of the sensor suite. This data is transmitted to the ground in raw digital counts, and subsequently converted into physical units by the ground system. Some of the data pertains to the temperature of components in the sensor suite.

The Primary source of data used to produce these files were from vessels of the following cooperatives: Cuba, Denmark, Finland, France, Germany (Federal Republic of Germany), Iceland, Ireland, Netherlands, Norway, Spain, Sweden, Tunisia, United Kingdom, U.S.S.R., Yugoslavia, Canada and the United States. Other countries were added later. The purpose of these cooperative ships were to take Meteorological Observations.