NB. This document is subject to updates when data become available and issues become known or resolved. Data description ================ The data contained in the QC files has been essentially cleaned up from the 30 second acquisition bursts measured by each buoy. Generally for each instrument (WQM - in water bio-geochemical measurements; CDM - in water CDOM fluorescence; NLF - in water nitrate measurements; MPB - meteorological parameters; HSE - hyperspectral irradiance) it is an average of 30 - 60 individual measurements. The main instrument is the WQM (temperature, salinity, oxygen, chlorophyll, suspended particulate matter) and all data are merged to these measurements. The header in each file gives the data type: Year Jd Time Dyear Lat Lon nw nc nn nm np SST SST_sd Sal Sal_sd Oxy Oxy_sd Chl Chl_sd SPM SPM_sd CDM CDM_sd Nit Nit_sd Prs Prs_sd Ta Ta_sd U U_sd V V_sd PAR Year - year Jd - Serial (Julian) day of year Dyear - decimal year Lat - latitude measured in degrees and decimal minutes i.e. 50.026 is 50 degrees 2.6 minutes Lon - Longitude measured in degrees and decimal minutes nw - number of WQM measurements in averaging nc - number of CDM measuremnets in averaging nm - number of meteorological measurements in averaging np - number of PAR measurements in averaging SST - sea surface temperature (at depth of 1.5 m) in degC SST_sd - SST standard deviation over period of measurements Sal - salinity at depth of 1.5 m in PSU Sal_sd - salinity standard deviation Oxy - Oxygen concentration in uM / kg Oxy_sd - oxygen concencentration standard deviation Chl - chlorophyll concentration mg/m3 Chl_sd - chlorophyll concentration standard deviation SPM - suspended particulate matter concentration (Nephelitic Turbidity Unit) SPM_sd - SPM standard deviation CDM - CDOM fluorescence (Quinine Sulphate fluorescence Units - QSU) CDM_sd - CDOM standard deviation Nit - Nitrate concentration (uM) - this has been calibrated against in situ measurements and corrections applied Nit_sd - Nitrate concentration standard deviation Prs - Atmospheric pressure (mb) Prs_sd - Atmospheric pressure standard deviation Ta - Air temperature (deg C) - about 4 m above sea surface Ta_sd - Air temperature standard deviation U - zonal (W/E) wind speed (m/s) U_sd - zonal wind speed standard deviation V - meridional (S/N) wind speed (m/s) V_sd - meridional wind speed standard deviation PAR - Photosynthetically Active Radiation (W/m2) - calculated from hyperspectral UV - UV Radiation (W/m2) - calculated from hyperspectral (350 - 380 nm) irradiance sensor - hyperspectral data is available on request Buoy specific information and data quality issues ================================================= L4 == Dates of deployment =================== 2009 076 - 347: deployment at L4. Storms hit the buoy around day 317 and crippled some of the systems before she was finally brought in around day 347. During that period the data are reliable but intermittant. 2010 100 - 343 - deployment at L4. The buoys were then switched around with the E1 buoy being deployed at L4 2010 344 - 2011 061: deployment at L4 using the E1 buoy hull and instruments. 2011 061 - 2011 286: deployment at L4 using L4 buoy hull. Power issues cut deployment short. Known issues ============ During 2011 there were several periods of bio-fouling which are difficult to interpret or form a definitive data for start points. The occurrences are obvious from the data and are shown as sharp and unrealistic peaks in the chlorophyll, CDOM and turbidity sensors. The temperature and salinity are unaffected by this. Instument details ================= HSE - Satlantic hyperspectral downwelling irradiance - unit 0298: calibrated 13/12/2007 CDM - WetLabs ECO CDOM fluorometer - S/N FLCDS-1302: calibrated 11/2/2009 StorX unit 052 NLF - Satlantic ISUS nitrate sensor - S/N 0167: calibrated 3/12/2007 - baseline correction checked in August 2008 found to be OK - although need for correction against in situ data in the field GPS, MPB - AirMar PB100 met head 3772 - unsure when calibrated - although sometime before 17/12/2007; does both GPS and met data. WQM - Wetlabs WQM sensor - S/N 0032 for 2008 data; S/N ***** for 2009 data - calibrated 11/2/2009 NB. The instruments for the period 2010 344 - 2011 061 used the E1 buoy setup - see below. E1 == Dates of deployment =================== 2008 - some useable data before instruments dropped off the rig 2009 218 - 319: 100 days in the field before power systems failed. Problem early on the in deployment with power and data communications (227 - 264) 2010 160 - 201: large storm on St. Swithin's day crippled power, just as a large bloom was occurring. 2011 076 - 318: power issues affected acquisitions later on. Bio-fouling an issue during June and September. Need to look at the bio-optical data carefully before using. Instument details ================= HSE - Satlantic hyperspectral downwelling irradiance - unit 0297: calibrated 13/12/2007 CDM - WetLabs ECO CDOM fluorometer - S/N FLCDS-: calibrated 11/2/2009 StorX unit NLF - Satlantic ISUS nitrate sensor - S/N GPS, MPB - AirMar PB100 met head; does both GPS and met data. WQM - Wetlabs WQM sensor - S/N All enquiries to Tim Smyth. All data should be used with care and if any publications arise, please contact: tjsm@pml.ac.uk ============ Tim Smyth 19/3/2012