blast3_readme.txt 25/09/96 16:36 ================= =============================================================================== Jurgen M. Lobert, James H. Butler, Shari A. Yvon, Stephen A. Montzka, Richard C. Myers, James W. Elkins. National Oceanic and Atmospheric Administration, Climate Monitoring and Diagnostics Laboratory, Nitrous Oxide And Halocompounds group (NOAA/CMDL/NOAH) mail contact: NOAA/CMDL/NOAH, 325 Broadway R/E/CG1, Boulder, CO 80303, USA email contacts: jbutler@cmdl.noaa.gov, jelkins@cmdl.noaa.gov, jlobert@cmdl.noaa.gov, syvon@cmdl.noaa.gov, smontzka@cmdl.noaa.gov =============================================================================== data ftp server: ftp.cmdl.noaa.gov, subdirs /noah/ocean/blast3 data web server: ftp://ftp.cmdl.noaa.gov/noah/ocean/blast_iii/ ---------------------------------------------------------------------- If you use any of these data, please acknowledge this source! ---------------------------------------------------------------------- The files in this directory are from the NOAA/CMDL Nitrous Oxide and Halocompounds group's BLAST III ocean expedition. BLAST III took place in the Antarctic Ocean from McMurdo, Antarctica to Punta Arenas, Chile between 18 February and 07 April, 1996. The following files are available in this directory: =========== bl3_met.dat =========== Saved in UNIX text format. A datafile with meteorological, position and other ancillary data. The first line of the file contains the headers listed below. There are 6119 rows of data with a spacing of 10 minutes between data points. Most of those data were taken from the ship's sensors except where stated. These data start at the beginning of the cruise and end at the 200-mile territorial zone (04-April, 1996,14:19 UT) of Chile and Argentina, we did not have permission to sample in territorial waters. The gas-specific data start at a much later date and end at the 200 mile zone. Missing data are replaced by the string "NAN" = "not a number". Column name data format remarks ---------------------------------------------------------------------- A minus sign in front of the format means that this column contains at least some data with a minus sign. Date123 5.5 Universal Date and time in spreadsheet format, e.g. 35119.11944 for the 24. of February, 1996, 02:52:00 universal time. DOY 2.5 decimal Julian day of year 1996 (universal time) Year 4.5 decimal year = DOY/366+1996 Latitude -2.5 Latitude in degrees, negative is south of the equator (all of them) Longitude -3.5 Lonitude in degrees east OR west (we crossed the dateline) LongitudeE 3.5 Longitude in degrees WEST (all positive) AirTemp -2.2 Air temperature in °C. WndSpdTru 2.3 True wind speed in m/s. The true wind speed was calculated from the speed over ground (SOG) instead of the speed through water (which was not measured) and has a slight inaccuracy in it. WndDirTru 3.3 True wind direction in degrees. WndSpdTru10 2.3 True wind speed corrected to an altitude of 10m above sea level (m/s). WndSpdRel 2.3 Wind speed relative to the ship (m/s). WndDirRel 3.3 Wind direction relative to the ship's heading in degrees. All wind-related data do not have an entry in the last 209 lines due to a broken anemometer (actually it was lost). SOG 2.3 speed over ground (m/s). COG 3.3 course over ground (degrees) Gyro 3.3 ship's heading, the direction in which the ship's bow is pointing, which is different from the actual movement in strong winds (degrees). Distance1 5.0 The distance travelled calculated from the speed over ground and the elapsed time (km). Distance2 5.0 The distance travelled calculated from the latitude and longitude data (km), both distances diverge about 1%. TSG_SST -2.3 Temperature of the TSG = thermosalinograph, which delivered salinity and was also linked to the fluorometer (°C). The first 13 lines do not contain any data. Kiel_SST -2.3 Temperature of the sea surface water, measured at the water intake line (°C).The first 13 lines do not contain any data. Salinity 2.5 salinity from the TSG (PSU). The first 13 lines do not contain any data. Fluorometer 1.6 fluorometer output signal, adjusted for range changes (a.u.). The first 917 lines do not contain any data. Chlorophyl_a 1.3 Chlorophyll-a concentration (micrograms per liter). The first 917 lines do not contain any data. =========== warming.dat =========== Saved in UNIX text format. This is a file that contains temperature data (along with date and day of year) to calculate the warming between sea surface temperature measured at the ship's intake line and the shower-head type equilibrator, which was located in the laboratory three decks up from the intake line. This warming is needed to correct for the solubility change of the gases in seawater. Column name data format remarks ---------------------------------------------------------------------- Date123 5.5 Universal Date and time in spreadsheet format, e.g. 35119.11944 for the 24. of February, 1996, 02:52:00 universal time. DOY 2.5 decimal Julian day of year 1996 (universal time) Temp_SST -2.2 sea surface temperature measured at the ship's water intake line. (°C) Temp_EQ 2.2 seawater temperature in the equilibrator (°C) Warming 2.2 warming = Temp_EQ - Temp_SST (°C). This dataset matches the injections of our GC/MS system and has a total of 1917 data rows between 24 February, 1996 and the 200 mile zone (04-April, 1996,14:19 UT) ============= bl3_ch3br.dat ============= Data for methyl bromide (CH3Br) from our BLAST III cruise. This file contains all ancillary data such as cruise track, meteorological data etc. You do not need BL3_MET.DAT for this. Keep in mind that both air and water samples were analyzed at different times (alternating with calibration gases), hence analysis times do not line up for both air and water. Instead of providing the user with two different sets of data for air and water, in this dataset we shifted the water results to the next earlier air sample. We shifted only the entire dataset, not individual rows. Wherever there was either an air or water sample missing, we deleted that particular row and removed it from the dataset, which reduced the dataset by about 110 values (out of ~ 990 total). Wind speed and direction are missing after 03- April, 04:00 am, because the anemometer got blown off the ship. For flux calculations, we assumed an average taken from the last 20 rows. All missing values were replaced with the number "9999". Disregard those values or replace them with a string that your program can handle. Here are the column headers and their meaning: Date Universal Date and time in spreadsheet format, e.g. 35119.11944 for the 24. of February, 1996, 02:52:00 universal time. DOY decimal Julian day of year 1996 (universal time) DecimalYear decimal year = DOY/366+1996 Latitude Latitude in degrees, negative is south of the equator (all of them) Longitude Lonitude in degrees east OR west (we crossed the dateline) LongitudeE Longitude in degrees WEST (all positive) SST Temperature of the sea surface water, measured at the water intake line (°C). TH_EQ Water temperature in the equilibrator in °C. Warming warming = TH_EQ - SST (°C). H2Ovapor Water vapor pressure in hPa (mbar) AirTemp Air temperature in °C. WndSpdTru True wind speed in m/s. The true wind speed was calculated from the speed over ground (SOG) instead of the speed through water (which was not measured) and has a slight inaccuracy in it. WndSpdTru10 True wind speed corrected to an altitude of 10m above sea level (m/s). WndDirTru True wind direction in degrees. WndSpdRel Wind speed relative to the ship (m/s). WndDirRel Wind direction relative to the ship's heading in degrees. SOG speed over ground (m/s). COG course over ground (degrees) Gyro ship's heading, the direction in which the ship's bow is pointing, which is different from the actual movement in strong winds (degrees). Distance The distance travelled (km). TSG_SST Temperature of the TSG = thermosalinograph, which delivered salinity and was also linked to the fluorometer (°C). The first 13 lines do not contain any data. Salinity salinity from the TSG (PSU). The first 13 lines do not contain any data. Chlorophyl_a Chlorophyll-a concentration (micrograms per liter). The first 917 lines do not contain any data. MFair Dry Mole Fraction of CH3Br (in ppt) in air PPair Partial pressure (in pico-atm) of CH3Br (in ppt) in air. This is the mole fraction corrected for water vapor pressure. MFwater Dry Mole Fraction of CH3Br (in ppt) in air that was equilibrated with surface water. MFwaterC Dry mole fraction (ppt) in equilibrated water corrected for warming (3.546%/degree) PPwaterC Warming corrected partial pressure in equilibrated air. Other gases will follow at a later point in time.