Flags description

The quality flag field consists of 32 bits. Every bit is related to the absence or presence of a a flag as described in the table below. The quality flag value given in each data level is the compound value of the specific bits of each raised flag. Some flags are left as placeholders for future updates. Note, additional flags can be added, the table below presents the flags used in the current version. The tables below also have a column for the Anomalies (processing errors) raised by a particular quality checks.

Table 1: Common Flags description

Bit #	name	network	level	Description	anomaly raised
1	lon_default	L & W	L0A	Default longitude as given in the configuration file is used (missing Lon in metadata)
2	lat_default	L & W	L0A	same as `lon_default’ but for latitude
3	pt_ref_invalid	L & W	L0A	No effective pan/tilt is returned and the requested pan/tilt was used instead
4	bad_pointing	L & W	L0A	Difference between requested and effective pan/tilt angle is >= 3°	`a’
5	outliers	L & W	L1A	If the spectrally integrated signal of the scan is more than 3 sigma or more than 25% (whichever is largest) removed from the mean; it is masked and will not be used when averaging the series. This process is repeated until convergence and applied to the measured (ir)radiances and to the darks.
6	L0_threshold	L & W	L1A	Check if any of the spectral pixels are saturated; i.e. digital number DN>=64000
7	L0_discontinuity	L & W	L1A	Check if there are missing values in the spectrum; or significant discontinuities (Delta DN>10^4)
8	dark_masked	L & W	L1A	If any of the darks have been masked by `outliers’; `L0_threshold’; and/or; `L0_discontinuity’
9	half_of_scans_masked	L & W	L0B	Less than half of the scans for a series passed quality checks `bad_pointing’; `outliers’; `L0_threshold’; and; `L0_discontinuity’
10	not_enough_dark_scans	L & W	L0B	Not enough valid dark scans for this series (# valid dark scans < n_valid_dark from the config file)	`nld’
11	not_enough_rad_scans	L & W	L0B	Not enough valid radiance scans for this series (# valid radiance scans < n_valid_rad from the config file)	`nlu’
12	not_enough_irr_scans	L & W	L0B	Not enough valid irradiance scans for this series (# valid irradiance scans < n_valid_irr from the config file)	`ned’
13	series_missing	L & W	L1B	Check if there are any missing series (either not present or flagged by `not_enough_dark_scans’; `not_enough_irr_scans’; `not_enough_rad_scans’ or `vza_irradiance’)	`ms’
14	vza_irradiance	L & W	L1B	One of the irradiance measurements did not have theta_v=180° (within 2° tolerance) so has been masked
15	no_clear_sky_irradiance	L & W	L1B	More than 10% of the wavelength bands have a difference of more than 50% with the clear-sky model
16	variable_irradiance	L & W	L1B	More than 10% difference between start and end E_d at 550~nm
17	half_of_unc_too_big	L & W	L1B	More than 50% of data has random error above 100% (likely corrupted or dark data)	`o’
18	single_irradiance_used	L & W	L1C	If only one series of irradiance is used for the computation of the reflectance
19	no_clear_sky_sequence	L & W	L1C	If all irradiance series are flagged with the `no_clear_sky_irradiance’ flag	`cl’

Table 2: Land-specific Flags description

Bit #	name	network	level	Description	anomaly raised
20	discontinuity_VNIR_SWIR	L	L1B	Checks if the VNIR and SWIR are different by more than 25%	`d’

Table 3: Water-specific Flags description

Bit #	name	network	level	Description	anomaly raised
20	single_skyradiance_used	W	L1C	If only one series of downwelling radiance is used for the computation of the reflectance
21	lu_eq_missing	W	L1C	If there is no upwelling and downwelling radiance pair with similar pointing azimuth angles (within 1° tolerance)	`l’
22	rhof_angle_missing	W	L1C	If there is no downwelling radiance scans at the appropriate viewing zenith angle (i.e. 180°-theta_v; within 1° tolerance)	`l’
23	rhof_default	W	L1C	If the viewing geometry of the upwelling and downwelling radiance measurements are outside the viewing geometry range of the selected LUT for the `rhof_option’ (e.g. Delta phi > 180° when using the LUT from Mobley et al 1999 a default rho_F is used for the air-water interface correction factor (default: rho_F=0.0256)
24	temp_variability_irr	W	L1C	If the difference in E_d scans does not exceed a given threshold between two neighbouring scans (default: threshold = 25% for wavelength = 550nm; see also Ruddick et al. (2006))
25	temp_variability_rad	W	L1C	If the difference in L_d or L_u scans does not exceed a given threshold between two neighbouring scans (default: threshold = 25% for wavelength = 550nm; Ruddick et al. (2006))
26	min_nbred	W	L1C	If the total number of scans not flagged by either `L0_threshold’; `bad_pointing’ or `outliers’ is less than a given threshold (default: 3)	`ned’
27	min_nbrlu	W	L1C	If the total number of scans not flagged by either `L0_threshold’; `bad_pointing’ or `outliers’ is less than a given threshold (default: 3)	`nlu’
28	min_nblsky	W	L1C	If the total number of scans not flagged by either `L0_threshold’; `bad_pointing’ or `outliers’ is less than a given threshold (default: 3)	`nld’
29	def_wind_flag	W	L1C	If a default wind speed is used (by default: wind speed = 2m/s)
30	simil_fail	W	L1C	If the quality check applied on the NIR similarity spectrum is not verified as suggested by Ruddick et al. (2005) (see Section 3.2 and Fig. 4 in Ruddick et al. (2005)) with default values for the computation of the NIR Similarity being 780 and 870~nm; the reference wavelength 670~nm and the threshold 5%