Print sigma coordinates nicely

src/dynamics/vertical_coordinates.jl

@@ -13,6 +13,18 @@ end
 # obtain nlev from length of predefined σ_half levels
 SigmaCoordinates(σ_half::AbstractVector) = SigmaCoordinates(nlev=length(σ_half)-1;σ_half) 
 
+function Base.show(io::IO,σ::SigmaCoordinates)
+    println("$(σ.nlev)-level SigmaCoordinates:")
+    nchars = length(string(σ.nlev))
+    format = Printf.Format("%$(nchars)d")
+    for k=1:σ.nlev
+        println(" k=",Printf.format(format,k-1),".5  -- $(Float16(σ.σ_half[k]))")
+        σk = (σ.σ_half[k] + σ.σ_half[k+1])/2
+        println(" k=",Printf.format(format,k),"    ×  $(Float16(σk))")
+    end
+    print(" k=",Printf.format(format,σ.nlev),".5  -- $(Float16(σ.σ_half[end]))")
+end
+
 """Coefficients of the generalised logistic function to describe the vertical coordinate.
 Default coefficients A,K,C,Q,B,M,ν are fitted to the old L31 configuration at ECMWF.