netcdf s4dvar_obs {

dimensions:
	survey = 1 ;
	state_variable = 7 ;
	datum = UNLIMITED ; // (0 currently)
variables:
        int spherical ;
                spherical:long_name = "grid type logical switch" ;
                spherical:flag_values = "0, 1" ;
                spherical:flag_meanings = "Cartesian spherical" ;
	int Nobs(survey) ;
		Nobs:long_name = "number of observations with the same survey time" ;
	double survey_time(survey) ;
		survey_time:long_name = "survey time" ;
		survey_time:units = "day" ;
	int obs_type(datum) ;
		obs_type:long_name = "model state variable associated with observation" ;
                obs_type:flag_values = "1, 2, 3, 4, 5, 6, 7" ;
		obs_type:flag_meanings = "zeta ubar vbar u v temperature salinity" ;
	int obs_provenance(datum) ;
		obs_provenance:long_name = "observation origin" ;
		obs_provenance:flag_values = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 ;
		obs_provenance:flag_meanings = "gridded_AVISO_SLA blended_SST XBT_Met_Office CTD_temperature_Met_Office CTD_salinity_Met_Office ARGO_temperature_Met_Office ARGO_salinity_Met_Office CTD_temperature_CalCOFI CTD_salinity_CalCOFI CTD_temperature_GLOBEC CTD_salinity_GLOBEC" ;
	double obs_time(datum) ;
		obs_time:long_name = "time of observation" ;
		obs_time:units = "day" ;
	double obs_depth(datum) ;
		obs_depth:long_name = "depth of observation" ;
		obs_depth:units = "meter" ;
		obs_depth:negative = "downwards" ;
	double obs_Xgrid(datum) ;
		obs_Xgrid:long_name = "x-grid observation location" ;
		obs_Xgrid:left = "INT(obs_Xgrid(datum))" ;
		obs_Xgrid:right = "INT(obs_Xgrid(datum))+1" ;
	double obs_Ygrid(datum) ;
		obs_Ygrid:long_name = "y-grid observation location" ;
		obs_Ygrid:top = "INT(obs_Ygrid(datum))+1" ;
		obs_Ygrid:bottom = "INT(obs_Ygrid(datum))" ;
	double obs_Zgrid(datum) ;
		obs_Zgrid:long_name = "z-grid observation location" ;
		obs_Zgrid:up = "INT(obs_Zgrid(datum))+1" ;
		obs_Zgrid:down = "INT(obs_Zgrid(datum))" ;
	double obs_error(datum) ;
		obs_error:long_name = "observation error covariance" ;
		obs_error:units = "squared state variable units" ;
	double obs_value(datum) ;
		obs_value:long_name = "observation value" ;
		obs_value:units = "state variable units" ;
	double obs_meta(datum) ;
		obs_meta:long_name = "observation meta value" ;
		obs_meta:units = "associated state variable units" ;

// global attributes:
		:type = "ROMS Observations" ;
		:title = "California Current System, 1/3 degree resolution (WC13)" ;
		:Conventions = "CF-1.4" ;
		:grd_file = "wc13_grd.nc" ;
		:state_variables = "\n",
			"1: free-surface (m) \n",
			"2: vertically integrated u-momentum component (m/s) \n",
			"3: vertically integrated v-momentum component (m/s) \n",
			"4: u-momentum component (m/s) \n",
			"5: v-momentum component (m/s) \n",
			"6: potential temperature (Celsius) \n",
			"7: salinity (nondimensional)" ;
		:obs_provenance = "\n",
			" 1: gridded AVISO sea level anomaly \n",
			" 2: blended satellite SST \n",
			" 3: XBT temperature from Met Office \n",
			" 4: CTD temperature from Met Office \n",
			" 5: CTD salinity from Met Office \n",
			" 6: ARGO floats temperature from Met Office \n",
			" 7: ARGO floats salinity from Met Office \n",
			" 8: CTD temperature from CalCOFI \n",
			" 9: CTD salinity from CalCOFI \n",
			"10: CTD temperature from GLOBEC \n",
			"11: CTD salinity from GLOBEC " ;
		:source = "http://hadobs.metoffice.com/en3" ;
		:history = "4DVAR observations, Monday - June 21, 2010 - 11:00:00 AM" ;
}