Rothermel

Dynamic fuel load transfer from live herbaceous to dead herbaceous fuel based on live-herbaceous fuel moisture, per Andrews (2018) Table 6c. Migrated from WildlandFire.jl@126976f2 src/rothermel.jl:320 (`DynamicFuelLoadTransfer` @component). Observed-only: w0_live_herb and Mf_live_herb are inputs (parameters); T_fraction, w0_dead_herb, and w0_live_herb_remaining are algebraic outputs.

Effective midflame wind speed UE — combines the actual wind factor and slope factor into an equivalent wind speed for fire-behavior calculations. Migrated from WildlandFire.jl@126976f2 src/rothermel.jl:410 (`EffectiveMidflameWindSpeed` @component). Observed-only: C_coeff, B_coeff, E_coeff, beta_ratio, phi_w, phi_s are inputs (parameters); phi_E (combined wind+slope factor) and UE (effective midflame wind speed in m/s) are algebraic outputs. Implements Eq. UE, Table 7, Andrews (2018) RMRS-GTR-371.

Live fuel moisture of extinction (M_x,live) from dead-fuel moisture, dead-to-live effective load ratio, and dead fuel moisture of extinction. Migrated from WildlandFire.jl@126976f2 src/rothermel.jl:367 (`LiveFuelMoistureExtinction` @component). Observed-only: Mx_dead, W_ratio, Mf_dead are inputs (parameters); Mx_live is an algebraic output. Implements Eq. M_x,live, Table 6b in Andrews (2018) RMRS-GTR-371.

Rothermel (1972) surface fire spread model — predicts rate of spread (R), fireline intensity (IB), flame length (F_L), and related outputs from fuel-bed properties, fuel moisture, wind speed, and terrain slope. Migrated from WildlandFire.jl@126976f2 src/rothermel.jl:70 (`RothermelFireSpread` @component). Observed-only (algebraic): all 27 unknowns are defined by algebraic equations; no ODE states. Implements Table 3 and Table 7 in Andrews (2018) RMRS-GTR-371 using SI units. All empirical coefficients are converted from US customary. See reference notes for the complete Unicode→ASCII identifier map and the coupling interface (RothermelCoupler couple2 methods).

Maximum effective wind speed (U_limit) above which the wind factor in the Rothermel surface fire spread model saturates. Migrated from WildlandFire.jl@126976f2 src/rothermel.jl:465 (`WindLimit` @component). Observed-only: IR is the input parameter; U_limit is the algebraic output. Both upstream branches are preserved here as a single `ifelse` on the dimensionless `use_corrected` indicator parameter — corrected (Andrews et al. 2013) when use_corrected > 0.5 (the upstream default), original when use_corrected ≤ 0.5. Implements Eq. Ulimit, Table 7 in Andrews (2018) RMRS-GTR-371.