Preliminary in-field dataset for derived fluxes and measured near-surface meteorology and seawater data
ATOMIC 2020, NW Tropical Atlantic
10-min resolution
NOAA Earth System Research Lab Physical Sciences Division (NOAA/ESRL/PSD)
Please acknowledge: NOAA/ESRL/PSD: Elizabeth Thompson, Chris Fairall, Sergio Pezoa
Dataset is subject to change as updates, corrections, and more data become available
Please contact Elizabeth Thompson if errors are found or if changes/additional variables are requested.
Contact: elizabeth.thompson@noaa.gov
Notes:
- wind data have been corrected for ship motion, except for the relative winds
- all fluxes are bulk fluxes calculated with COARE 3.5 algorithm
References for COARE: Fairall et al. 1996a, 1996b, 2003, Edson et al. 2013)
- several other parameters in this file (Tstar, ustar, L, exchange coefficients, dT_skin, dz_skin, etc.) are derived by COARE, not measured.
Sign Conventions:
- fluxes: meteorological convention
positive = out of ocean, cooling the ocean, warming the atmosphere
negative = into the ocean, warming the ocean, cooling the atmosphere
- wind: meteorological convention
direction = the direction wind came from
Sensors:
- Data in this file are from PSD sensors unless otherwise noted (ship data: Ttsg, Stsg, _s variables)
- all NOAA ESRL PSD sensors are located on foremast except sea snake, radiometers, pressure, heading, and GPS.
The radiometers are mounted on top of the forward starboard O2 deck van
The sea snake was in the water dangling from forward portside main deck rail
The pressure, heading, and GPS are from sensors on forward portside O2 deck rail
- ship sensors are either on foremast (rotating propellor for wind), on top of pilot house (all others),
or on forward portside O2 deck rail (radiometers)
- skin T of seawater computed by NOAA ESRL PSD / APL-UW (Applied Physics Laboratory at Univ of Washington)
using a ROSR unit on port O2 deck rail pointed roughly 45deg to port, as far away from the ship wake as possible
% NOAA ESRL PSD sensor heights above water or depth below water (m)
zu = 18.0; % wind speed measurement height
zt = 17.0; % air T measurement height
zq = 17.0; % air q measurement height
zp = 14.40; % pressure measurement height
zsnk = 0.05; % sea snake measurement depth
% ship sensor heights above sea level (m)
zu_ship = 18.5928; % wind speed measurement height
zt_ship = 17.0942; % air T measurement height
zq_ship = 17.0942; % air q measurement height
zp_ship = 15.6337; % air P measurement height
ztsg_ship = 5.334; % depth of TSG intake
zrad_ship = 10.1981; % radiometer measurement height
Data Quality Notes:
- use psd data (no suffix) over ship data (_s suffix) because data quality of former is better
Header for text file found in companion file: header_ATOMIC_2020_10min_flux_met_sea_data.txt
(same spacing as data fields - length/spacing = 20 per field)
number of variables in txt file: 89 (not all the same vars as mat file - see below)
number of variables in mat file: 89 (not all the same vars as txt file - see below)
Explanation or non data-type fields in matlab structure (not in text file):
readme = explains creation of file
cruise_str = 'ATOMIC' ... used for plotting
PosLims = [Lonmin, Lonmax, Latmin, Latmax]... Lonmin = -63; Lonmax = -45; Latmin = 8; Latmax = 20;
ztsg_ship = depth of ship TSG
Fields in Matlab structure ff and columns in text file, alphabetical order with capital letters first
month, day, year, minute, second, and jd are the date/time variables for .txt file
t, jd are the date/time varibales for .mat file (t = matlab datetime)
Cd: [144×1 double] drag coefficient = turbulent exchange coefficient for wind stress adjusted for 10-m height and neutral atmospheric stability, unitless
Ce: [144×1 double] Dalton number = turbulent exchange coefficient for evaporation adjusted for 10-m height and neutral atmospheric stability, unitless
Ch: [144×1 double] Stanton number = turbulent exchange coefficient for sensible heat assuming adjusted for 10-m height and neutral atmospheric stability, unitless
L: [144×1 double] Monin Obukhov length scale, m
Stsg: [144×1 double] ship thermosalinograph SBE 45 salinity, psu
T10: [144×1 double] air T adjusted for 10-m height and neutral atmospheric stability, C
Ta: [144×1 double] air T at height zt, C
Ta_s: [144×1 double] ship air T at height zt_ship, C
Tskin: [144×1 double] skin T of seawater from ROSR infrared radiometer, C (true SST felt by atmosphere)
Tsnk: [144×1 double] sea snake T at depth zsnk, C
Tstar: [144×1 double] temperature scaling parameter, K
Ttsg: [144×1 double] ship thermosalinograph SBE 38 T at depth ztsg_ship, C
U10: [144×1 double] wind speed adjusted to 10 m, m/s
Ue: [144×1 double] eastward wind speed, m/s
Un: [144×1 double] northward wind speed, m/s
cog: [144×1 double] course over ground, deg
cog_s: [144×1 double] ship course over ground, deg
dT: [144×1 double] air-sea T difference = SST-T10, C
dT_skin: [144×1 double] cool-skin temperature depression, C
day: [144×1 double] day
dq: [144×1 double] air-sea q difference = qs-q10, g/kg
dz_skin: [144×1 double] cool-skin vertical thickness, m
evap: [144×1 double] evaporation rate, mm/hr
hed: [144×1 double] heading, deg
hl: [144×1 double] bulk latent heat flux, W/m2
hl_covS: [144×1 double] direct covariance latent heat flux, W/m2 (Simon de Szoeke's method)
hl_covW: [144×1 double] direct covariance latent heat flux, W/m2 (Webb method)
hl_id: [144×1 double] inertial dissipation latent heat flux, W/m2
hl_s: [144×1 double] bulk latent heat flux from ship data, W/m2
hnet: [144×1 double] net heat flux, W/ms (hnet = lwnet + swnet + hl + hs + hr)
hour: [144×1 double] hour
hr: [144×1 double] rain heat flux, W/m2
hs: [144×1 double] bulk sensible heat flux, W/m2
hs_covS: [144×1 double] direct covariance sensible heat flux, W/m2 (Simon de Szoeke's method)
hs_covW: [144×1 double] direct covariance sensible heat flux, W/m2 (Webb method)
hs_id: [144×1 double] inertial dissipation sensible heat flux, W/m2
hs_s: [144×1 double] bulk latent heat flux from ship data, W/m2
jd: [144×1 double] decimal julian date
lat: [144×1 double] latitude, deg
licor_AGC: [144×1 double] quality control flag for licor data. Good data (data present) when licor_AGC < 60.
lon: [144×1 double] longitude, deg
lw_dn: [144×1 double] downwelling long wave radiation, W/m2
lw_net: [144×1 double] net long wave radiation, W/m2
lw_s: [144×1 double] ship downwelling long wave radiation, W/m2
lw_up: [144×1 double] upwelling long wave radiation, W/m2
minute: [144×1 double] minute
month: [144×1 double] month
paccum: [144×1 double] daily accumulated precipitation, mm
prate: [144×1 double] instantaneous precipitation rate from optical rain gauge, mm/hour
q10: [144×1 double] air specific humidity adjusted for 10-m height and neutral atmospheric stability, g/kg
qa: [144×1 double] air specific humidity at height zt, zq, zp, g/kg
qa_licor: [144×1 double] air specific humidity at height zq from licor, g/kg
qa_s: [144×1 double] ship air specific humidity at height zt, zq, zp, g/kg
qs: [144×1 double] saturation specific humidity at surface from sst, g/kg
qstar: [144×1 double] specific humidity scaling parameter, g/kg
rdir: [144×1 double] relative wind direction, deg
rdir_s: [144×1 double] ship portside relative wind direction, deg
rh: [144×1 double] relative humidity at height zq, %
rh10: [144×1 double] relative humidity adjusted for 10-m height and neutral atmospheric stability, %
rh_licor: [144×1 double] relative humidity from licor, %
rh_s: [144×1 double] ship relative humidity at height zq_ship, %
rhoa: [144×1 double] density of air at height zt_ship, kg/m3
rhoa_licor: [144×1 double] density of air at height zq from licor, kg/m3
rspd: [144×1 double] relative wind speed, m/s
rspd_s: [144×1 double] ship relative wind speed, m/s
slp: [144×1 double] sea level pressure, mb
sog: [144×1 double] speed over ground, m/s
sog_s: [144×1 double] ship speed over ground, m/s
sst: [144×1 double] calculated skin-level sea surface temperature from Tsnk - calculated cool skin (dter), C
sw_dn: [144×1 double] downwelling short wave radiation, W/m2
sw_net: [144×1 double] net short wave radiation, W/m2
sw_s: [144×1 double] ship downwelling short wave radiation, W/m2
sw_up: [144×1 double] upwelling short wave radiation, W/m2
tau: [144×1 double] bulk wind stress, N/m2
tau_cov: [144×1 double] direct covariance wind stress, N/m2
tau_ida: [144×1 double] inertial dissipation type A wind stress, N/m2
tau_idb: [144×1 double] inertial dissipation type B wind stress, N/m2
tau_s: [144×1 double] ship bulk wind stress, N/m2
tilt: [144×1 double] tilt angle from first rotation, radians
uplat_std: [144×1 double] platform velocity std deviations x-direction for u, m/s
ustar: [144×1 double] friction velocity that includes gustiness, m/s
vplat_std: [144×1 double] platform velocity std deviations x-direction for v, m/s
wdir: [144×1 double] true wind direction, deg
wdir_s: [144×1 double] ship true wind direction, deg
wplat_std: [144×1 double] platform velocity std deviations x-direction for w, m/s
wspd: [144×1 double] true wind speed, m/s
wspd_s: [144×1 double] ship true wind speed, m/s
year: [144×1 double] year
zet: [144×1 double] Monin-Obukhov stability parameter zu/L, unitless