Climatology of Total Cloudiness in the Arctic: An Intercomparison of Observations and Reanalyses

Table 2

Satellite-based datasets information.

Dataset	Satellite	Spectral channels(visible (VIS), near infrared (NIR), infrared (IR))	Time of observations (local time)	Instrument resolution / swath (km)	Cloud detection algorithm
APP-x	LEO (NOAA)	1 VIS + 1 NIR + 3 IR	~14:00, 2:00	1−4 /~3000	A combination of the spectral and temporal uniformity tests which are tuned specially for the polar regions [52].
CERES	LEO (Terra, Aqua)	1 VIS + 1 NIR + 3 IR	10:30, 22:30; (Terra); 01:30, 13:30; (Aqua)	0,25−1 /2330	Series of the spectral threshold tests (different between night and day) [55].
ISCCP	GEO + LEO (NOAA)	1 VIS + 1 IR	every 3 hour	4−7 /—	The spectral threshold test and a combination of the spatial and temporal uniformity tests [57].
MODIS	LEO (Terra, Aqua)	1 VIS + 1 NIR + 3 IR	10:30, 22:30; (Terra); 01:30, 13:30; (Aqua)	0,25−1 /2330	Series of the spectral threshold tests and a combination of the spatial and temporal uniformity tests. Special tests for the polar regions [59, 60].
PATMOS-x	LEO (NOAA)	1 VIS + 1 NIR + 3 IR	14:00, 2:00	1−4 /~3000	CLAVR-x (series of the spectral threshold tests) + Naïve Bayesian methodology [62].