HOTSSea Model v1 monthly outputs

Monthly outputs from the Hindcast of the Salish Sea (HOTSea) v1.02 (temperature bias corrected) 1980 - 2018. Monthly statistics (mean, min, max, standard deviation) are processed from daily mean model outputs of temperature and salinity. The monthly data are provided for the surface, bottom layer, and for several depth strata (0to30m, 30to150m, 150mtoBottom). In the cases where depth strata are provided, the daily means are first processed to monthly. Then, the depth integrated mean is produced. For example, the 'min' temperature for 0 to 30 m is produced by taking the minimum mean daily temperature across the month at each modelled depth. Then, the depth integrated mean of these mins is produced. Rationale is provided on the 'pacea' R data repository. The monthly data are then stored in NC files. See the parent publication for model details. 

outputs v4 - added min, max, standard deviation, changed name conventions, fixes to indexing over depths, fix to fill_values and missing vals to be compatible with R.