I am trying to get landsat reflectance values corresponding to field plots spread all over Finland using the Google Earth Engine. As you know, Finland is up North, between latitudes of ~60 and 70 degree N. I am extracting from this landsat collection. Upon examining the extracted values, I noticed that most (99.9%) of the pixels have a 'pixel_qa' value of 322. From my understanding of the bitmask, I gathered that the value of '322' means that the 'cloud confidence' and the 'cirrus confidence' was low. Why is this? Can I still assume that the cloud/noncloud classification is good enough?
I got a reply from someone at USGS: "You want low confidence in clouds, that means that there is very little chance that there is a cloud there when there shouldn't be. A value of 322 means that the pixels are clear and there are not clouds present."
So, in conclusion, a value of 322 is okay to work with.