The columns are as follows:

jdy=x(:,1);%julian day at beginning of 5-min average
U=x(:,2); %true wind speed, m/s; etl sonic anemometer (18.5 m)
dir=x(:,3);%true wind direction (from), deg (clockwise rel north)
tsnk=x(:,4);%sea snake temperature, C (0.05 m depth)
tsg=x(:,5);%tsg water temperature, C (5 m depth)
sal=x(:,6);%tsg salinity, psu (5 m depth)
ta=x(:,7);%air temperature, C (z=15.5 m)
qse=x(:,8);%sea surface specific humidity, g/kg
qa=x(:,9);%air specific humidity, g/kg (z=15.5 m)
rs=x(:,10);%downward solar flux, W/m^2 (ETL units)
rl=x(:,11);%downward IR flux, W/m^2 (ETL units)
org1=x(:,12);%rainrate, mm/hr (ETL STI optical rain gauge #1, uncorrected)
ushp=x(:,13);%ship speed, m/s (SCS gps)
head=x(:,14);%ship heading, deg clockwise rel north (SCS laser ring gyro)
urel=x(:,15);%relative wind speed, m/s (ETL sonic)
reldir=x(:,16);%relative wind direction (from), deg clockwise rel ship's bow(ETL sonic)
Lat=x(:,17);%latitude, DDMM.MMMM  (SCS pcode)
Lon=x(:,18);%longitude, DDDMM.MMMM (SCS pcode)
zts=x(:,19);%depth for bulk flux Ts reference, =0.05 when snake is used
sig_u=x(:,20);%std dev of ship speed, m/s (>.2 indicates maneuver)
Taub=x(:,21);%bulk wind stress along mean wind, N/m^2
Hsb=x(:,22);%bulk sensible heat flux, W/m^2
Hlb=x(:,23);%bulk latent heat flux, W/m^2 (includes Webb et al. correction)
Hrain=x(:,24);%rain heat flux, W/m^2 as per Gosnell et al
Ta_im=x(:,25);% IMET air temp, C (15 m)
Qa_im=x(:,26);% IMET air specific humidity, g/kg (15 m)
U_im=x(:,27);% IMET true wind speed, m/s (15 m)
Dir_im=x(:,28);% IMET true wind direction, deg (15 m)
Psp_im=x(:,29);% IMET solar flux, w/m^2
Pir_im=x(:,30);% IMET IR flux, w/m^2