DDAI-7: Add script to produce total column water

himan-scripts/tcw.lua

@@ -0,0 +1,26 @@
+-- Produce total column water for MEPS / MNWC
+-- "This parameter is the sum of water vapour, liquid water, cloud ice, 
+-- rain and snow in a column extending from the surface of the Earth to 
+-- the top of the atmosphere."
+-- Source: https://codes.ecmwf.int/grib/param-db/136
+
+local tcwv = luatool:Fetch(current_time, level(HPLevelType.kEntireAtmosphere, 0), param("TOTCWV-KGM2"), current_forecast_type)
+local cldice = hitool:VerticalSum(param("CLDICE-KGKG"),8,15000)
+local cldwtr = hitool:VerticalSum(param("CLDWAT-KGKG"),8,15000)
+local snowmr = hitool:VerticalSum(param("SNOWMR-KGKG"),8,15000)
+local rainmr = hitool:VerticalSum(param("RAINMR-KGKG"),8,15000)
+local graupmr = hitool:VerticalSum(param("GRAUPMR-KGKG"),8,15000)
+
+if not tcwv or not cldice or not cldwtr or not snowmr or not rainmr or not graupmr then
+  logger:Error("Data not found")
+  return
+end
+
+local tcw = {}
+for i=1, #tcwv do
+  tcw[i] = tcwv[i] + cldice[i] + cldwtr[i] + snowmr[i] + rainmr[i] + graupmr[i]
+end
+
+result:SetParam(param("TCW-KGM2"))
+result:SetValues(tcw)
+luatool:WriteToFile(result)