ISBA

ISBA-ES model: ISBA soil-vegetation coupled to an Explicit Snow scheme

The mass (water) and heat transfer pathways and reservoirs/stores. There are 3 snow layers considered in the current configuration, and 3 prognostic variables for each layer: Snow Water Equivalent (W_si), layer average density (rho_si) and heat content (H_si). Surface albedo represents a fourth prognostoc variable. The heat content is used to diagnose the snow layer average temperature (T_i) and liquid water content (W_li).

Surface Energy budget/Fluxes

Incoming fluxes are in blue, outgoing are in green, turbulent exchanges with the atmosphere are in purple. Sub-surface heat fluxes are in red.

Hydrology

Water sources due to the various components of the precipitation are in blue, evapotranspiration sources/sinks are in green, and canopy drip, snowmelt runoff, surface runoff, drainage and soil water fluxes are in red.

Prognostic variables are in blue.

R_g	Incoming shortwave radiation (W m^-2)
R_at	Incoming longwave atmospheric radiation (W m^-2)
alpha R_g	Outgoing shortwave radiation (W m^-2)
R_l	Outgoing longwave atmospheric radiation (W m^-2)
H	Sensible Heat Flux (W m^-2)
LE	Latent Heat Flux (W m^-2)
G	Ground Heat Flux (W m^-2)
T_s	Surface temperature (K)
T₂	Deep soil or Restore temperature (K)
H_si	Snow Heat Content (J m^-2)

P_r	Total Precipitation (kg m^-2 s^-1)
P_n	Snowfall (liquid equiv.) (kg m^-2 s^-1)
P_s	Precipitation reaching soil (kg m^-2 s^-1)
P_v	Precipitation intercepted by vegetation (kg m^-2 s^-1)
P_g	Infiltration (kg m^-2 s^-1)
Q_r	Surface runoff (kg m^-2 s^-1)
D₁	Surface/deep soil soil water diffusion (kg m^-2 s^-1)
K₂	Gravitational drainage (kg m^-2 s^-1)
E_n	Sublimation (kg m^-2 s^-1)
E_g	Bare-soil evaporation (kg m^-2 s^-1)
E_r	Evaporation from interception (kg m^-2 s^-1)
E_tr	Transpiration (kg m^-2 s^-1)
W_r	Canopy water store (kg m^-2)
W_si	Snow pack SWE (Snow Water Equiv.) (kg m^-2)
w_g	Surface soil water reservoir (m³ m^-3)
w₂	Bulk soil water reservoir (m³ m^-3)
w_sf	Surface soil ice reservoir (m³ m^-3)
w_2f	Sub-surface soil ice reservoir (m³ m^-3)
d_s	Surface reservoir soil depth (m)
d₂	Total soil depth (m)

Additional Prognostic variables are

alpha_n	Snow surface albedo
rho_si	Snowpack mean density