Handle NaNs when integrating

NaNs are treated as zeros when integrating.

NEWS.md

@@ -70,6 +70,7 @@ if duplicate dates are detected.
 - Fix issue with plotting multiple figures at the same time.
 - Improve shading for `Visualize.heatmap2D_on_globe!`.
 - Add support for automatically converting CFTime.AbstractCFDateTime dates to seconds.
+- Treat `NaN`s as zeros when integrating (`integrate_lon, integrate_lat, integrate_lonlat`)
 
 v0.5.10
 -------

src/Numerics.jl

@@ -1,6 +1,7 @@
 module Numerics
 
 import ..Utils: _isequispaced
+import NaNStatistics: nansum
 
 """
     _integrate_lon(data::AbstractArray, lon::AbstractVector; dims)
@@ -67,7 +68,7 @@ function _integrate_over_angle(
     size_to_reshape =
         (i == angle_idx ? length(int_weights) : 1 for i in 1:ndims(data))
     int_weights = reshape(int_weights, size_to_reshape...)
-    int_on_angle = sum(data .* int_weights, dims = angle_idx)
+    int_on_angle = nansum(data .* int_weights, dims = angle_idx)
     return int_on_angle
 end
 

src/Var.jl

@@ -1129,6 +1129,8 @@ If the points are equispaced, it is assumed that each point correspond to the mi
 cell which results in rectangular integration using the midpoint rule. Otherwise, the
 integration being done is rectangular integration using the left endpoints for integrating
 longitude and latitude. The units for longitude and latitude should be degrees.
+
+All `NaN`s in `var.data` are treated as zeros when integrating.
 """
 function integrate_lonlat(var::OutputVar)
     var_integrate_lon = var |> integrate_lon
@@ -1150,6 +1152,8 @@ If the points are equispaced, it is assumed that each point correspond to the mi
 cell which results in rectangular integration using the midpoint rule. Otherwise, the
 integration being done is rectangular integration using the left endpoints. The unit for
 longitude should be degrees.
+
+All `NaN`s in `var.data` are treated as zeros when integrating.
 """
 function integrate_lon(var::OutputVar)
     has_longitude(var) || error("var does not has longitude as a dimension")
@@ -1167,6 +1171,8 @@ If the points are equispaced, it is assumed that each point correspond to the mi
 cell which results in rectangular integration using the midpoint rule. Otherwise, the
 integration being done is rectangular integration using the left endpoints. The unit for
 latitude should be degrees.
+
+All `NaN`s in `var.data` are treated as zeros when integrating.
 """
 function integrate_lat(var::OutputVar)
     has_latitude(var) || error("var does not has latitude as a dimension")

test/test_Numerics.jl

@@ -92,7 +92,7 @@ end
         dims = 1,
     )
 
-    # Integrating only lon (non equispaced)
+    # Integrating only lon (equispaced)
     lon = collect(range(-179.5, 179.5, 360))
     lon_data = ones(length(lon))
     @test isapprox(
@@ -101,7 +101,7 @@ end
         atol = 0.01,
     )
 
-    # Integrating only lat (non equispaced)
+    # Integrating only lat (equispaced)
     lat = collect(range(-89.5, 89.5, 180))
     lat_data = ones(length(lat))
     @test isapprox(
@@ -110,4 +110,19 @@ end
         atol = 0.01,
     )
 
+    # Integrating with NaNs
+    lon = collect(range(-179.5, 179.5, 360))
+    lon_data = ones(length(lon))
+    lon_data[:] .= NaN
+    @test ClimaAnalysis.Numerics._integrate_lon(lon_data, lon, dims = 1)[1] ==
+          0.0
+
+    lon = collect(range(-179.5, 179.5, 360))
+    lon_data = ones(length(lon))
+    lon_data[1:180] .= NaN
+    @test isapprox(
+        ClimaAnalysis.Numerics._integrate_lon(lon_data, lon, dims = 1)[1],
+        1.0π,
+        atol = 0.01,
+    )
 end