The CLAVR-1 cloudmask (Stowe, 1999) is used to cloudmask AVHRR high resolution sea surface temperature products. The cloudmask runs a series of tests on each surface temperature pixel to determine whether the pixel is contaminated by cloud cover. Users may evaluate which specific tests in the cloudmask returned positive cloud presence results by examining the value of the cloudmask. This value corresponds to an 8 bit binary number which details which tests flagged the pixel as a cloudy pixel. See https://coastwatch.pfeg.noaa.gov/info/CLAVR.html for more information regarding the specific tests used in the cloudmask.

The CLAVR-1 cloudmask (Stowe, 1999) is used to cloudmask AVHRR high resolution sea surface temperature products. The cloudmask runs a series of tests on each surface temperature pixel to determine whether the pixel is contaminated by cloud cover. Users may evaluate which specific tests in the cloudmask returned positive cloud presence results by examining the value of the cloudmask. This value corresponds to an 8 bit binary number which details which tests flagged the pixel as a cloudy pixel. See https://coastwatch.pfeg.noaa.gov/info/CLAVR.html for more information regarding the specific tests used in the cloudmask.

The CLAVR-1 cloudmask (Stowe, 1999) is used to cloudmask AVHRR high resolution sea surface temperature products. The cloudmask runs a series of tests on each surface temperature pixel to determine whether the pixel is contaminated by cloud cover. Users may evaluate which specific tests in the cloudmask returned positive cloud presence results by examining the value of the cloudmask. This value corresponds to an 8 bit binary number which details which tests flagged the pixel as a cloudy pixel. See https://coastwatch.pfeg.noaa.gov/info/CLAVR.html for more information regarding the specific tests used in the cloudmask.

This Summary of the Day data file contains daily selected elements of observations recorded by certified observers. The stations were located in the U.S. and were operated by the United States Weather Bureau (later the National Weather Service) and the Federal Aviation Administration (FAA). This data file spans 1945-1948. These first and second order stations were usually fully instrumented and therefore recorded a complete range of meteorological parameters. The observations were generally recorded for the 24-HR period midnight to midnight. There are a total of 169 stations with recorded observations in this dataset. Stations have varying periods of record and varying types of data elements. In the early years of aviation most stations were located in major cities. As aviation became more sophisticated, stations shifted to airports. Official surface weather observation standards can be found in the Circular N manuals. Images from which the data originated are available on a web based system owned by the National Climatic Data Center (NCDC)

The dataset consists primarily of U.S. surface airways observations (SAO) data beginning in 1965 and extending through 1981. Note that a few stations have already had certain years within this 1965-81 period re-keyed as hourly. For these stations, only a subset of the period was keyed. In addition, other stations did not have data keyed at all during this period, or during the periods immediately before or after the 1965-81 range. These stations data have been keyed to as thoroughly as possible complete their entire period of record back to July, 1948. The major data variables are as follows: WBAN Identification Station Number, observational type, ceiling and cloud, visibility, present weather, temperature, relative humidity, wind, pressure and precipitation. The observations are generally recorded for the 24 hour period midnight to midnight. The keying format was designed to reflect the data as entered on the page to make keying easier for the key entry personnel, who were not trained meteorological technicians. The "raw" observations which comprise this dataset will be quality checked to include data adjustments and converted to NCDC's Integrated Surface Hourly (ISH) format.

The dataset consists primarily of U.S. surface airways observations (SAO) data beginning in 1965 and extending through 1981. Note that a few stations have already had certain years within this 1965-81 period re-keyed as hourly. For these stations, only a subset of the period was keyed. In addition, other stations did not have data keyed at all during this period, or during the periods immediately before or after the 1965-81 range. These stations data have been keyed to as thoroughly as possible complete their entire period of record back to July, 1948. The major data variables are as follows: WBAN Identification Station Number, observational type, ceiling and cloud, visibility, present weather, temperature, relative humidity, wind, pressure and precipitation. The observations are generally recorded for the 24 hour period midnight to midnight. The keying format was designed to reflect the data as entered on the page to make keying easier for the key entry personnel, who were not trained meteorological technicians. The "raw" observations which comprise this dataset will be quality checked to include data adjustments and converted to NCDC's Integrated Surface Hourly (ISH) format.

The dataset consists of hourly U.S. surface airways observations (SAO). These observations extend as far back as 1928, from the time when commercial aviation began in the United States and meteorological observing stations were established at many airports (although occasionally, early-period SAO's were taken at U.S. Weather Bureau city offices). For most stations, this dataset extends through June of 1948. The major data variables are as follows: WBAN Station Identification Number, observational type, ceiling and cloud, visibility, present weather data, temperature, wind and pressure. The observations are generally recorded for the 24-hour period midnight to midnight, although many stations did not record 24-hour observations, especially early in the period when commercial aviation was just getting started. Two output keying formats were created to adjust to an observational form change during the period. One format was generally used for years 1928-33, and the other for sets from around 1934 through June of 1948. Each keying format was designed to reflect the data as entered on the observational form for ease of keying by key entry personnel, who were not trained meteorological technicians. The "raw" observations which comprise the DSI-3851 dataset were quality checked, to include data adjustments, and converted to NCDC's Integrated Surface Hourly (ISH) format. The complimentary data to this collection can be found in the Surface Weather Observation 1001 Forms (Keyed) collection.