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JCSDA / CRTMv3

CRTMv3 repository for coordinated development and releases. Code history is not carried in this repository prior to v3, to reduce the cloning overhead. For v2.x history leading up to v3, see JCSDA/crtm repository.
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Bug in NESDIS_LandEM_Module.f90 regarding Soil_Moisture_Content #30

Closed BenjaminTJohnson closed 5 months ago

BenjaminTJohnson commented 1 year ago

Soil_Moisture_Content is specified by input as g/cm^3 (according to the code and CRTM user guide), but gets restricted to [0,1] via the max/min operation below. I suspect that this was a confusion between a typical fractional expression of soil moisture content (e.g., cm^3/cm^3) and the content (g/cm^3).

i.e., in NESDIS_LandEM_Module.f90:

 ! By default use the
    ! Assign local variable
    mv               = Soil_Moisture_Content  

...

    ! Check soil moisture content range
    mv = MAX(MIN(mv,ONE),ZERO)

Recommended solution for v3: use a fractional value for inputs, and update the documentation / calling routines accordingly. Will need to check GSI / UFO as well. I suspect the impact has been limited since soil moisture contents are frequently less than 1 g/cm^3.

I remain, however, confused about finding soil moisture content values in the literature that are as high as 1.6 g/cm^3, considering that the density of pure water is 1 g/cm^3... seems like it would be impossible to have a value greater than 1.

BenjaminTJohnson commented 1 year ago

Additional information in this thread:

https://github.com/JCSDA-internal/ufo/issues/2301

StegmannJCSDA commented 1 year ago

I remain, however, confused about finding soil moisture content values in the literature that are as high as 1.6 g/cm^3, considering that the density of pure water is 1 g/cm^3... seems like it would be impossible to have a value greater than 1.

@BenjaminTJohnson if I understand correctly, fluid flow through porous media like soil isn't necessarily considered incompressible, so the mass density can exceed $1.0$ $\frac{g}{cm^3}$, as long as conservation of (water) mass requires it.

chengdang commented 1 year ago

Link comments on this topic https://github.com/JCSDA-internal/fv3-jedi/issues/852#issuecomment-1513464270

BenjaminTJohnson commented 1 year ago

@chengdang can you follow up on this issue, and review the relevant details regarding expected ranges of input for soil moisture -- also have a look at the UFO interface, to ensure that the values are being passed into CRTM as expected.

chengdang commented 1 year ago

@BenjaminTJohnson Sure, I'll follow up on this.

chengdang commented 5 months ago

@BenjaminTJohnson, this issue should be closed for now and move to AOP 2024