The water balance equation for change of soil moisture storage in a soil is given as where S is storage, P is precipitation, E is evaporation, and R is surface runoff plus percolation rate into the groundwater zone; all terms are in units of length per unit of time (e.g., millimetres per day, centimetres per month).
We define the storage-adjusted runoff (Q′) as the sum of actual runoff (Q) and the rate of change in soil moisture storage (ΔS/Δt, positive or negative) during the time step of interest.
The sum of rainfall and snowmelt from the snow routine enters the soil moisture routine, which calculates the changes in soil moisture storage as the difference between effective precipitation (rain or snowmelt), P (mm d−1), and actual evapotranspiration, ETA (mm d−1).
Stony soils are known to have reduced nutrients and moisture storage ability (Macadam 1989).
Recently, they have been employed to explore the impact of climate change (McCabe and Ayers 1989), estimate the global water balance (Mather 1969; Legates and McCabe 2005), river runoff (Wolock and McCabe 1999) and soil moisture storage (Mintz and Serafini 1992), and to develop climate classifications (Thornthwaite 1948) and irrigation demand (McCabe and Wolock 1992).
LFD is inversely related to deep soil moisture storage, so LFD is short or absent when deep soil moisture storage is near capacity.
The model explicitly considers moisture storage in the soil.
Relying on such moisture storage, native shrubs can survive better than long-lived grasses, that is, stand vigorously to maintain an ecosystem (Schulze et al. 1996).
For example [ 40], notes that in drier places (with shallow soils or with less soil moisture storage capacity) of the reserve the woodland is shorter and more open.
The enhancements of global forcing data (meteorological data, solar radiation, soil moisture stress and water storage changes) and model physics (reasonable consideration of the water and energy balance and vegetation processes such as canopy interception loss) will undoubtedly improve the estimation of global ET in the future.
