Oden celiometer cloud data

The file OdenCloudBase zip-file contains ascii and matlab formated version of the data from Odens celiometer which has been reasonably cleaned up.

There are several issues with this data set and to make things easier the 30-seond data was first reduced to 5-minute medians. After this it was found that, with the capacity to keep track of more than one cloud layer, only two layers gave significant input so only those two are retained, "Layer_1" being the lowest. For both these layers there is a 5-minute median cloud base height and cloud fraction. Keep in mind that with two layers where the lowest is broken, the second higher layer will become the lowest when the lowest temporarily goes away.

Additionally there are also "verical visibility and total cloud cover. The vertical visibility is used when the is dense; for these the cloud base is always at its lowest height, but the verical visibility may still be significantly large; this happens for example in a vertically thin fog, where the horisotnal visibility may be severely restricted but one can still see the sky (or other clouds) through the top of the fog. The cloud cover is given in octas (0-8) where 8 octas is completely overcast. A cloud cover of 9 octas signifies "sky obscured" as in very dense fog.

Note that the "total cloud cover" sems to relate poorly to the cloud cover for either of the layers; have no clue as to why so I suggest using the individual layer cloud cover with caution.

The data in the file is:

1:  UTC time (DoY)
2:  Year
3:  Month
4:  Day
5:  Hour
6:  Minute
8:  Longitude (deg)
9:  Latitude (deg)
10: Lowest (1st) cloud layer base (m)
11: Lowest (1st) cloud layer fraction (0-8,9)
13: 2nd cloud layer base (m)
11: 2nd cloud layer fraction (0-8,9)
12: Vertical visibility (m)
13: Total cloud fraction (0-8,9)

Obviously Unreasonable values have been replaced by NaN.

OdenCloudBase.zip1.22 MB