add new atmosperic composition parameter in Code Table 4.2.0.20

Author: sebvi

GRIB2_CodeFlag_4_2_0_20_CodeTable_en.csv

@@ -18,7 +18,8 @@ Parameter number by product discipline and parameter category,"Product disciplin
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",16,,Mass mixing ratio with respect to dry air,,,kg/kg,Operational
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",17,,Mass mixing ratio with respect to wet air,,,kg/kg,Operational
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",18,,Potential of hydrogen (pH),,,pH,Operational
-Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",19-49,,Reserved,,,,Operational
+Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",19,,Loss rate due to reaction with hydroxyl radical (OH),,,kg kg-1 s-1,Operational
+Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",20-49,,Reserved,,,,Operational
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",50,,Amount in atmosphere,,,mol,Operational
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",51,,Concentration in air,,,mol m-3,Operational
 Parameter number by product discipline and parameter category,"Product discipline 0 - Meteorological products, parameter category 20: atmospheric chemical constituents",52,,Volume mixing ratio (fraction in air),,,mol/mol,Operational