============================================================================== Data Description NOAA Coral Reef Watch Satellite Virtual Stations Time Series Data (Last update: 30 March 2011) ============================================================================== Site-specific, near-real-time time series data extracted from NOAA Coral Reef Watch's (CRW) operational twice-weekly satellite coral bleaching monitoring products are provided for CRW's Satellite Virtual Stations at selected reef sites worldwide. The time series data cover December 2000 to the present. Both operational and experimental Virtual Stations products can be accessed at: http://coralreefwatch.noaa.gov/satellite/current/products_vs.html CRW's bleaching monitoring products are derived from satellite nighttime sea surface temperatures (SSTs) observed by the Advanced Very High Resolution Radiometer (AVHRR) instrument carried on NOAA's Polar Orbiting Environmental Satellites (POES). Monitoring product descriptions and associated methodology are available at the CRW web site: http://coralreefwatch.noaa.gov/satellite/index.html. Time series data are currently updated twice-weekly on Monday and Thursday mornings (U.S. Eastern Time) when the CRW operational global products are updated. The Monday update provides four-day composite data of the preceding Thursday, Friday, Saturday, and Sunday; the Thursday update provides three-day composite data of the preceding Monday, Tuesday, and Wednesday. Prior to May 3 2007, data were updated on Tuesday and Saturday mornings (U.S. Eastern Time); the switch to Monday and Thursday mornings is identifiable in the date of the time series data records. The Tuesday and Saturday updates provided three-day composite data of the preceding Saturday, Sunday, and Monday and four-day composite data of the preceding Tuesday, Wednesday, Thursday and Friday. The data file for the operational products is in ASCII text format. The first row of each file is the header, providing titles for each field in the record. There are 15 fields in each record, described in detail below. Each row provides data for one twice-weekly composite. BYYY, BM, BD, BH (beginning time): These are the year, month, day, and hour (GMT time), respectively, that begin the composite time period of a record, showing the hour of the first satellite measurement processed for the record. During a successful twice-weekly data update, the BYYY, BM, BD, BH are identical to the EYYY, EM, ED, and EH (see below), respectively, of the previous record. Only nighttime SST observations are used for coral bleaching monitoring. The POES orbit period, which is the time it takes to complete one orbit of the Earth, is approximately 100+ minutes. In the time series, a gap between the begin time (BYYY,BM,BD,BH) of a composite record and the end time (EYYY,EM,ED,EH) of the previous record indicates that data might have been lost during the gap. EYYY, EM, ED, EH (ending time): These are year, month, day, and hour (GMT time), respectively, of the last (i.e., newest) nighttime SST measurement processed for the record. In a time series, if a composite's ending time (EYYY, EM, ED, EH) is much later than the usual ending time associated with its scheduled product processing time described above or is out of the pattern of most of the ending times in the time series, a technical glitch might have occurred at the time of data processing; data processing then resumed at a later time and included any additional observations available at that time. The beginning time and ending time together define the time period for a composite. SST: Twice-weekly sea surface temperature (SST) composite value for the 0.5x0.5 degree pixel; units are degrees Celsius. Details about the SST product can be found at: http://coralreefwatch.noaa.gov/satellite/current/products_sst.html. SSTANOM: SST Anomaly value; units are degrees Celsius. The anomaly is the difference between the SST and the daily climatological SST. Information on the SST Anomaly product and the operational climatology can be found at: http://coralreefwatch.noaa.gov/satellite/current/products_ssta.html. HOTSPOT: Coral Bleaching HotSpots value; units are degrees Celsius. HotSpots values are greater than zero when bleaching thermal stress is present. Information on the Coral Bleaching HotSpots product can be found at: http://coralreefwatch.noaa.gov/satellite/current/products_hotspot.html. DHW: Bleaching Degree Heating Weeks (DHW) value in the units of degree Celsius-weeks. The DHW is a measure of thermal stress accumulated over a 12-week period. Details about the DHW product can be found at: http://coralreefwatch.noaa.gov/satellite/current/products_dhw.html. Lat and Lon: Latitude and longitude of the center of the pixel in units of degrees-north and degrees-east, respectively. Reef_Name: The name of the reef site to which the virtual station is associated. ----------------------------------------------------------------------- NOAA Coral Reef Watch (coralreefwatch.noaa.gov)