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Which variable in CESM-LME can represent water-holding capacity to calculate the PDSI?

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lona

Hongnaxu
New Member
Dear all,

The water-holding capacity is necessary for calculating the Palmer Drought Severity Index (PDSI), and it represents available soil water capacity of the soil.

In the CESM-LME simulations, there are five variables relevant to soil moisture:
(1) H2OSOI (unit: mm3/mm3): volumetric soil water (vegetated landunits only);
(2) SOILLIQ (unit: kg/m2): soil liquid water (vegetated landunits only);
(3) SOILPSI (unit: MPa): soil water potential in each soil layer;
(4) SOILWATER_10CM (unit: kg/m2): soil liquid water + ice in top 10cm of soil (veg landunits only);
(5) WT (unit: mm): total water storage (unsaturated soil water + groundwater veg landunits).

Which variable can represent water-holding capacity to calculate the PDSI?

Looking forward to your reply. Thanks a lot!

Hongna Xu
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
I'm not exactly sure what is required here. WATSAT is the porosity of the soil. However, my understanding is that water-holding capacity is usually calculated as field capacity minus wilting point (i.e., plant available water)? There are a couple of instances of these concepts in CLM. One calculation of field capacity is watfc in SoilStateInitTimeConstMod.F90, but that history field is off by default. The wilting point concept is used in IrrigationMod.F90. So maybe these quantities could be calculated from soil texture and other soil properties.
 
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