SGP/VISST/X1 - Algorithm version 4.1 instead of 4.0

During the original processing in 2012, 5 days 2012-02-17/21 were missing because of 
missing model input data. In 2015, the data for the entire month were reprocessed using an 
alternate source for the model profiles to fill in this gap.
The VISST process in use in 2015 is a slightly improved version 4.1 compared to the 
original v. 4.0.
Improvements include:
1) Updated cloud mask to improve low cloud detection in twilight
2) Reduced false cloud detection over desert and ocean
3) Improvements in multi-layer cloud detection (such as classifying deep convective clouds 
as single layer clouds)
4) For GOES-xx satellites: for GOES-12 onwards, 12um channel is missing. In V4.1 a 2 
channel algorithm using only 11 & 3.9um channels is used at night.

Be aware of potential slight discontinuities when comparing to data before and after 

this time period. To assess difference in process version you can request data from 
armarchive@arm.gov that was archived prior to 2015.

• cloud_top_pressure
• temperature_sw
• visible_optical_depth
• reflectance_vis
• ir_cloud_emittance
• cloud_effective_height
• broadband_longwave_flux
• temperature_ir
• cloud_bottom_height
• cloud_effective_temperature
• cloud_effective_pressure
• cloud_phase
• cloud_top_height
• reflectance_nir
• particle_size
• liquid_water_path
• cloud_bottom_pressure
• temperature_sir
• broadband_shortwave_albedo