3.0 NSRDB Synoptic Format--CDROM Format When data for multiple years are requested in a single file, the years will follow each other hour by hour with no end-of-file until the end of the data. The first record before each year contains the WBAN number, city, state, time zone, latitude (degrees and minutes), longitude (degrees and minutes), and elevation (meters). Time zones are indicated in terms of the number of hours by which the local standard time lags or leads Universal Time (UT). For example, Mountain Standard Time at Albuquerque is designated as -7, to indicate a lag of 7 hours from UT (i.e., a UT of 1700 corresponds to a time of 1000 [10 AM] in Albuquerque). The field positions and definitions of these header elements are given below in Table 3-1 along with the FORTRAN format required to read the header. Following the header, there are 8,760 or 8,784 (for leap years) hourly data records in each station-year. Each of the elements found in each data record are defined below in Table 3-2. @@@ Quality Flags for Solar Radiation Elements: Two flags are used to define the quality of each solar radiation element. The first flag gives the user information about the source of each hourly value for each solar radiation element, including the methods and input data used to derive model estimates. Solar radiation source flags are defined in Table 3-6. The flags are ranked roughly from highest quality to lowest quality data. However, this ranking may not hold for an individual datum. For example, if the quality assessment of data from a station measuring all three elements of solar radiation (Source Flag A) shows a large probable error in the data, then a large uncertainty will be assigned to the hourly values for each element. This might be a larger uncertainty than that assigned to a modeled value with good quality input data. The second flag designates the uncertainty attached to each hourly value. Uncertainty as used here provides an estimate of the interval around a measured or modeled value within which the true value will lie 95% of the time. The flags for each interval are defined below in Table 3-7. @@@ In Version 1.0 of the NSRDB, no flags as low as 1 or as high as 9 were assigned. In general, the uncertainties assigned to measured solar radiation data show considerable variability because of instrument failures and human factors. The uncertainties assigned to modeled data will be higher, on average, than measured data, but will show lower variability for a given source category because the model is applied uniformly at all times. Only changes in the uncertainty of the input data will significantly affect the uncertainty of modeled data. @@@ Table 3-1. Header Elements in the NSRDB CDROM-Synoptic Format (For first record of the file) Fld Position Element Definition 001 - 001 Indicator A '~' to indicate the header record. 002 - 006 WBAN Number Station's Weather Bureau Army Navy number. 008 - 029 City City where the station is located (maximum of 22 characters). 031 - 032 State State where the station is located (abbreviated to two letters). 034 - 036 Time Zone Time zone is the number of hours by which the local standard time lags or leads Universal Time. For example, Mountain Standard Time is designated -7 because it lags Universal Time by 7 hours. @@@ 039 - 044 Latitude Latitude of the station. 039 N = North of equator 040 - 041 Degrees 043 - 044 Minutes 047 - 053 Longitude Longitude of the station. 047 W = West, E = East 048 - 050 Degrees 052 - 053 Minutes 056 - 059 Elevation Elevation of station in meters above sea level. FORTRAN Format (1X,A5,1X,A22,1X,A2,1X,I3,2X,A1,I2,1X,I2,2X,A1,I3,1X,I2,2X,I4) @@@ Table 3-2. Data Elements in the NSRDB Synoptic Format (For all except the first record in the file). "Field" shows the numeric identifier for each field. These identifiers will appear in the second record (after the header record shown above) of the users output file to identify the data selected by the user. The data will occupy the third record and all ensuing records until a new year of data occurs. Then, the header record and identifier record are repeated. The numbers shown below in parenthesis show the position of each element within that field. Each field is separated by 1 blank. @@@ Field Element Values Definition Time Local Standard Time (1-8) Year 61-90 Year of observation Month 1-12 Month of observation Day 1-31 Day of month Hour 1-24 Hour of day in local standard time I Observation Indicator 0 or 9 0 = Weather observation made. 9 = Weather observation not made or missing. If this field = 9 OR if field 13 (wind speed) = missing (9999. or 99.0), then fields 6, 7, 8, 10, 11, 17, and 18 were all modeled and not actually observed. @@@ 1 Extraterrestrial 0-1415 Amount of solar radiation in (1-4) Horizontal Radiation Wh/m2 horizontal surface at the top of the atmosphere during the 60 minutes preceding the hour indicated. 2 Extraterrestrial 0-1415 Amount of solar radiation in (1-4) Direct Normal Wh/m2 received on a surface Radiation normal to the sun at the top of the atmosphere during the 60 minutes preceding the hour indicated. @@@ 3 Global Horizontal Total amount of direct and Radiation diffuse solar radiation in (1-4) Data Value 0-1415 Wh/m2 on a horizontal surface (6) Flag for Data A-H,? during the 60 minutes preceding Source the hour indicated. (7) Flag for Data 0-9 9999 = missing data. Uncertainty See tables below for Source Flag and Uncertainty Flag. 4 Direct Normal Amount of solar radiation Radiation in Wh/m2 received within a 5.7 degrees (1-4) Data Value 0-1415 field of view centered on the (6) Flag for Data A-H, ? sun, during the 60 minutes Source preceding the hour indicated. (7) Flag for Data 0-9 9999 = missing data. Uncertainty See tables below for Source Flag and Uncertainty Flag. @@@ 5 Diffuse Horizontal Amount of solar radiation Radiation in Wh/m2 received from the sky (1-4) Data Value 0-1415 (excluding the solar disk) on a (6) Flag for Data A-H, ? horizontal surface, during the Source 60 minutes preceding the hour (7) Flag for Data 0-9 indicated. Uncertainty 9999 = missing data. See tables below for Source Flag and Uncertainty Flag. 6 Total Sky_Cover 0-10 Amount of sky dome (in tenths) (1-2) covered by clouds. 99 = missing data. @@@ 7 Opaque Sky_Cover 0-10 Amount of sky dome (in tenths) (1-2) covered by clouds that prevent observing the sky or higher cloud layers. 99 = missing data. 8 Dry Bulb -70.0 to Dry bulb temperature in degrees C. (1-5) Temperature 60.0 9999. = missing data. 9 Dew_Point -70.0 to Dew_point temperature in degrees C. (1-5) Temperature 60.0 9999. = missing data. 10 Relative Humidity 0 - 100 Relative humidity in percent. (1-3) 999 = missing data. @@@ 11 Station 700 - 1100 Station pressure in (1-4) Pressure millibars. 9999 = missing data. 12 Wind Direction 0 - 360 Wind direction in degrees. (1-3) (N = 0 or 360, E = 90, S = 180, W = 270) 999 = missing data. 13 Wind Speed 0.0-99.0 Wind speed in m/s. (1-5) 9999. or 99.0 = missing data. 14 Visibility 0.0-160.9 Horizontal visibility in (1-6) kilometers. 777.7 = unlimited visibility. 99999. = missing data. 15 Ceiling Height 0-30450 Ceiling height in meters. (1-6) 77777 = unlimited ceiling height. @@@ 88888 = cirroform. 999999 = missing data. 16 Present_weather See Present_weather conditions (1-9) Table denoted by 9 indicators. Below See present weather table below. 17 Precipitable 0-100 Precipitable_water in (1-4) Water millimeters. 9999 = missing data. 18 Broadband Aerosol 0.0-0.900 Broadband aerosol optical_depth (1-6) Optical_Depth (broadband turbidity) on the day indicated. 99999. = missing data. @@@ 19 Snow_Depth 0-100 Snow_depth in centimeters on (1-4) the day indicated. 9999 = missing data. 20 Days Since Last 0 - 88 Number of days since last (1-3) Snowfall snowfall. 88 = 88 or greater days. 999 = missing data. 21 Hourly Precipitation 000000- In inches and hundredths (1-6) 099999 (See information below). (7) Hourly Precipitation See explanation below. Flag @@@ Present Weather Table Position Element Values Remarks (1) Occurrence 0 - 2, 0 = Thunderstorm - lightning of Thunder- 4, 6-9 and thunder + storm, wind gusts less than 25.7 Tornado, or m/s, hail (if any) < 1.9 cm Squall diameter. 1 = Heavy or severe thunderstorm - frequent intense lightning & thunder, wind gusts > 25.7 m/s and hail, if any, 1.9 cm or greater in diameter. 2 = Report of tornado or @@@ waterspout. 4 = Moderate squall - sudden increase of wind speed by at least 8.2 m/s, reaching 11.3 m/s or more and lasting for at least one minute. 6 = Water spout (beginning January 1984). 7 = Funnel cloud (beginning January 1984). 8 = Tornado (beginning January 1984). 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. @@@ (2) Occurrence of 0 - 9 0 = Light rain Rain Showers, 1 = Moderate rain or Freezing 2 = Heavy rain Rain 3 = Light rain showers 4 = Moderate rain showers 5 = Heavy rain showers 6 = Light freezing rain 7 = Moderate freezing rain 8 = Heavy freezing rain 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. Notes: Light = up to 0.25 cm per hour. Moderate = 0.28 to 0.76 cm per hour. Heavy = greater than 0.76 cm per hour. @@@ (3) Occurrence of 0, 1, 0 = Light rain squalls Rain Squalls, 3 - 9 1 = Moderate rain squalls Drizzle, or 3 = Light drizzle Freezing 4 = Moderate drizzle Drizzle 5 = Heavy drizzle 6 = Light freezing drizzle 7 = Moderate freezing drizzle 8 = Heavy freezing drizzle 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. (See below for notes) @@@ Notes: When drizzle or freezing drizzle occurs with other weather phenomena: Light = up to 0.025 cm per hour. Moderate = 0.025 to 0.051 cm per hour. Heavy = greater than 0.051 cm per hour. When drizzle or freezing drizzle occurs alone: Light = visibility 1 km or greater. Moderate = visibility between 0.5 & 1 km. Heavy = visibility 0.5 km or less. @@@ (4) Occurrence of 0 - 9 0 = Light snow Snow, Snow 1 = Moderate snow Pellets, or 2 = Heavy snow Ice Crystals 3 = Light snow pellets 4 = Moderate snow pellets 5 = Heavy snow pellets 6 = Light ice crystals 7 = Moderate ice crystals 8 = Heavy ice crystals 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. Notes: Beginning in April 1963, any occurrence of ice crystals is recorded as a 7. @@@ (5) Occurrence of 0-5, 9 0 = Light snow showers Snow Showers, 1 = Moderate snow showers or Snow Squalls 2 = Heavy snow showers 3 = Light snow squall 4 = Moderate snow squall 5 = Heavy snow squall 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. @@@ (6) Occurrence of 0 - 2, 0 = Light ice pellet showers Sleet, Sleet 4, 9 1 = Moderate ice pellet Showers, or showers Hail 2 = Heavy ice pellet showers 4 = Hail 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. Notes: Prior to April 1970, ice pellets were coded as sleet. Beginning in April 1970, sleet and small hail were redefined as ice pellets and are coded as 0, 1, or 2. @@@ (7) Occurrence of 0 - 9 0 = Fog Fog, Blowing 1 = Ice fog Dust, or 2 = Ground fog Blowing Sand 3 = Blowing dust 4 = Blowing sand 5 = Heavy fog 6 = Glaze (beginning 1984) 7 = Heavy ice fog (beginning 1984) 8 = Heavy ground fog (beginning 1984) 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. Notes: These values recorded only when visibility is less than 11 km. @@@ (8) Occurrence of 0-7, 9 0 = Smoke Smoke, Haze, 1 = Haze Smoke and Haze, 2 = Smoke and haze Blowing Snow, 3 = Dust Blowing Spray, 4 = Blowing snow or Dust 5 = Blowing spray 6 = Dust storm (beginning 1984) 7 = Volcanic ash 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. Notes: These values recorded only when visibility is less than 11 km. @@@ (9) Occurrence of 0-2, 9 0 = Light ice pellets Ice Pellets 1 = Moderate ice pellets 2 = Heavy ice pellets 9 = None if Observation Indicator element equals 0, else unknown or missing if Observation Indicator element equals 9. @@@ Notes: With the exception of solar radiation elements, broadband aerosol optical_depth, snow_depth, and days since last snowfall, all values were observed or measured at the hour indicated. Daily values of broadband aerosol optical_depth were estimated. HOURLY PRECIPITATION HISTORY AND DATA SOURCES The observations of hourly precipitation were taken by observers at principle (primary) stations, secondary stations, and cooperative observer stations operated by the National Weather Service (NWS) and the Federal Aviation Agency (FAA). @@@ Approximately 5,500 stations have recorded precipitation data through the period of record. Initially from August 1948 to September 1951, data were keyed on punched cards by the regional Weather Records Processing Centers. Then the task was transferred to the National Climatic Data Center (NCDC) in Asheville, NC. The hourly precipitation data file was transferred from punched cards to magnetic tape (TD-9657) during the late 1960s. This data file was then converted to an element file structure during 1984. Several recording (weighing) rain gauge instruments were used in measuring hourly precipitation, but by September 1963 many Fischer Porter precipitation gauge instruments with automated readout, recorded on paper tape, were phased in. By early 1965, about 200 of these were in operation and they became the primary recording instrument. Currently, there are approximately 2,000 Fischer Porter gauges in operation. The Universal Rain gauge is the other primary instrument used to create the data. It has an automated readout recorded on paper charts. Station and dates of @@@ commissioning of weighing rain gauges are in the Station History listings available at the NCDC in Asheville, NC. Precipitation values are checked and edited as necessary on an automated and manual edit. Data before 1984 were converted from existing digital files (TD-9747) to the element structure format. These (historical) data were processed through a gross value check only. Beginning January 1984, the hourly precipitation data were processed through a completely revised system which produces an element structure database file. Data are subjected to new computer editing procedures reducing the manual handling of the data. Areal coverage includes the United States, Puerto Rico, Virgin Islands, and U.S. protectorates located in the Pacific. @@@ DATA FORMAT--HOURLY PRECIPITATION It stands to reason that for most hours the non-occurrence of precipitation is prevalent. Therefore, in order to save space in the original digital file, there are entries only for: 1. The first day and hour of each month where observations were taken even if no precipitation occurred during that month. 2. Hours with precipitation > zero. 3. Beginning and ending hours of missing periods. 4. Beginning and ending hours of accumulating periods. 5. Beginning and ending periods of deleted data. 6. First and last day of each month where the required charts or forms never were received or processed at NCDC. The actual precipitation data value: The data value portion is a @@@ six-digit integer. Units are inches and hundredths. Range = 000000-099999. 000000 will be used only on the first hour of each month unless there is precipitation during that hour, in which case the measured value will be provided. On other days during the month without precipitation, no entry will be made. 099999 indicates that the value is unknown. Hourly Precipitation Flag: A Accumulated period and amount. An accumulated period indicates that the precipitation amount is correct, but the exact beginning and ending times are only known to the extent that the precipitation occurred sometime within the accumulation period. Begin accumulation data value will always be 099999. D Deleted Flag. Beginning and ending of a deleted period. A deleted value indicates that the original data were received, but were unreadable or clearly recognized as noise. @@@ M Missing Flag. (Beginning and ending of a missing Period.) A missing flag indicates that the data were not received. This flag appears on the first and last day of each month for which data were not received or not processed by NCDC. Prior to 1984 a missing period was recorded as " 00000M" at the beginning and ending hours. If precipitation occurred during the last hour of the missing period, the second M appears with a non- zero value. Beginning in 1984 the beginning and ending hours of the missing period are recorded as "099999M". b Blank. No Flag needed. Examples: The precipitation accumulation from 1st month day 02 to 2nd month day 04: @@@ 01 0002 0500 000030b 1000 099999A Accumulation begins 02 0001 0100 099999A Accumulation continues 0004 1400 000390A Accumulation ends Accumulated precipitation for 1 month only: 01 0002 1000 099999A Accumulation begins 0031 2400 000320A Accumulation ends Accumulated, deleted, and missing precipitation data through months 01 and 02: 01 0001 0100 000000b First record of the month 0002 1100 099999A Accumulation begins 02 0001 0100 099999A Accumulation continues 1400 000630A Accumulation ends @@@ 1500 099999D Deleted data begins 02 0028 1300 099999D Deleted data ends 1400 099999M Missing data 2400 099999M Missing data Required precipitation charts or forms were never received at NCDC: 01 0001 0100 099999M Missing data 0031 0100 099999M 02 0001 0100 099999M 0028 0100 099999M STATIONS WITH LITTLE OR NO HOURLY PRECIPITATION DATA: Traverse City MI Massena NY Bradford PA Washington-Dulles VA @@@ Mason City IA Minot ND Pierre SD Lufkin TX Eau Claire WI Tucumcari NM Cedar City IA Daggett CA Arcata CA Redmond OR North Bend OR Gulkana AK Big Delta AK Talkeetna AK Bettles AK Barrow AK Bethel AK Kotzebue AK Kahului HI @@@ Table 3-5. TD-3282 Codes for Units of Measurement Code Description of Measurement Units WM Solar radiation in Wh/m2 TC Temperature in Celsius and tenths (i.e., 205 = 20.5 Celsius) P Whole percent MB Station pressure in millibars WD Wind direction in tens of degrees (i.e., 18 = 180 degrees) WS Wind speed in m/s and tenths (i.e., 107 = 10.7 m/s) KM Kilometers and tenths (i.e., 503 = 50.3 kilometers) DM Decameters (1 decameter = 10 meters) CM Centimeters MM Millimeters NA No units applicable (non-dimensional) @@@ Table 3-6. Solar Radiation Source Flags Flag Definition A Post-1976 measured solar radiation data as received from NCDC or other sources B Same as 'A' except the global horizontal data underwent a calibration correction C Pre-1976 measured global horizontal data (direct and diffuse were not measured before 1976), adjusted from solar to local time, usually with a calibration correction D Data derived from the other two elements of solar radiation using the relation, Kt = Kn + Kd E Modeled solar radiation data using inputs of observed sky_cover (cloud amount) and aerosol optical_depth s derived from direct normal data collected at the same location @@@ F Modeled solar radiation using interpolated sky_cover and aerosol optical_depths derived from direct normal data collected at the same location G Modeled solar radiation data using observed sky_cover and aerosol optical_depths estimated from geographical relationships H Modeled solar radiation data using interpolated sky_cover and estimated aerosol optical_depths ? Source does not fit any of the above categories. Used for nighttime values, calculated extraterrestrial values, and missing data @@@ Table 3-7. Solar Radiation Uncertainty Flags Flag Uncertainty Range (%) 1 0 - 2 2 2 - 4 3 4 - 6 4 6 - 9 5 9 - 13 6 13 - 18 7 18 - 25 8 25 - 35 9 35 - 50 0 Not applicable Other References: {Help_Listings} {All_Elements }