Ther are 11 levels to the output NetCDF file. They are ... 

1  : Rank value for selected month(s)/year (1=highest rank).
2  : Minimum grid value in any year for selected month(s).
3  : Maximum grid value in any year for selected month(s).
4  : Climatology mean per grid cell.
5  : Climatology standard deviation per grid cell.
6  : Grid value for selected month(s)/year
7  : Grid value departure from climatology.
8  : Grid value std dev from climatology.
9  : Significance trend for entire period (-1 to +1. -0.99 is significant decreate at 99th percent level. +0.8 is significant increase at 80th percentile).
10  : Trend change for entire period (a linear regression trend line is computed for the time series. The trend change is the difference between the last, and first y-axis values of the regression line. 
11  : Missing values per grid cell (functionally only affects GISTEMP and Berkeley Earth).