Version 2 is the current version of this dataset. Version 2 uses an improved methodology to screen out high clouds. This data set provides an estimate the marine boundary layer water vapor beneath uniform cloud fields. Microwave radiometry from AMSR-E and AMSR-2 provides the total column water vapor, while the near-infrared imagery from MODIS provides the water vapor above the cloud layers. The difference between the two gives the vapor between the surface and the cloud top, which may be interpreted as the boundary layer water vapor.