0.01_r8 appears as a magic number in numerous places in the code.

The constant 0.01_r8 is used in multiple places in the code as a magic number. To make the context of the meaning behind the number more obvious it would be good to turn it into a parameter.

There is a defined parameter that might make sense for this in a few files:

src/biogeochem/CNGapMortalityMod.F90: mort_max = 0.01_r8 ! original value for all patches
src/biogeophys/CanopyFluxesMod.F90: real(r8), parameter :: dtmin = 0.01_r8 ! max limit for temperature convergence [K]
src/biogeophys/LakeCon.F90: real(r8), public, parameter :: cur0 = 0.01_r8 ! min. Charnock parameter
src/biogeophys/LunaMod.F90: PARi10 = 0.01_r8
src/biogeophys/LunaMod.F90: PARi10 = 0.01_r8
src/biogeophys/SnowHydrologyMod.F90: real(r8), public, parameter :: scvng_fct_mlt_dst3 = 0.01_r8 ! scavenging factor for dust species 3 inclusion in meltwater [frc]
src/biogeophys/SnowHydrologyMod.F90: real(r8), public, parameter :: scvng_fct_mlt_dst4 = 0.01_r8 ! scavenging factor for dust species 4 inclusion in meltwater [frc]
src/main/atm2lndType.F90: lapse_rate = 0.01_r8)
src/main/clm_varcon.F90: real(r8), public :: watmin = 0.01_r8 ! minimum soil moisture (mm)

There's about 100 references in about 22 files.

I think it's likely that many of these references really refer to watmin.