quick way in getting the trend of many NetCDF files

[szwang1990]

I have been using xarrya in reading nc files. Now I have 100 nc files with each storing 3D annual mean ocean temperature for each year between 2001-2100. So for each lon-lat-depth grid, how can I get the linear trend in 2001-2100? My method is to read all the 100 nc files once, but it is extremly slow and memory consuming.

Thanks in advance.