If you take a look at the dimensions of your data you will notice that it is wrapped into an additional layer (which could mean that it is kind of a 3D structure --- list of data):

data = Import["~/Downloads/test.nc",  {"Datasets",  "SST"}]; 
Dimensions[data]

(* ==> {1, 801, 1001} *)

So what you want to do here to plot the data, is getting rid of additional layer, which can be done as easy as:

data = First[data]; 
Dimensions[data]

(* ==> {801, 1001} *)

Now you can plot the data:

ArrayPlot[data]

Or you could plot it as it is:

ArrayPlot /@ data

All the rest, in the example from the documentation I refereed to, is matter of preference. For example here is how it looks when you reverse your data:

ArrayPlot[Reverse[data]]

Or, here is how the ColorFunction actually influences your plot:

ArrayPlot[Reverse[data],  ColorFunction -> "BlueGreenYellow"]

And so on, so force.

p.s. Please consider removing External Programs and Systems from your question's keywords, since it is not related to your question.