Laserfiche WebLink
Cooperative Institute for Research in Environmental Sciences <br />UNIVERSITY OF COLORADO BOULDER and NOAA <br />Radiative forcing <br />(sunshine, T) <br />Advective forcing <br />(wind, humidity, T) <br />ET0 =0.408D <br />D +g 1+CdU2()Rn -G()86400 <br />106 +g Cn <br />TD+g 1+CdU2()U2 <br />esat -ea() <br />103 <br />Drivers from NLDAS-2: <br />•temperature at surface (2 m) <br />•specific humidity at surface <br />•downward SW at surface <br />•wind speed (10 m) <br />Penman-Monteith reference ET equation: <br />ASCE Standardized reference ET / FAO-56 <br />Mean annual ET0 (mm), 1981-2010 <br />•daily, Jan 1, 1979 – present <br />•~12-km, CONUS-wide <br />λ = latent heat of vaporization <br />Rn = net radiation (SW + LW) at crop surface <br />G = ground heat flux <br />U2 = 2-m wind speed <br />esat / ea = saturated / actual vapor pressure <br />Δ = desat/dT at air temperature T <br />γ = psychrometric constant <br />Cn, Cd = constants for crop type and time-step <br />“Reference” crop is specified: <br />•0.12-m grass or 0.50-m alfalfa <br />•well-watered , actively growing <br />•completely shading the ground <br />•albedo of 0.23 <br />NOAA’s reference ET (ET0) reanalysis <br />Estimating E0 from ET0 <br />Driving data can also come from <br />•station observations <br />•remote sensing <br />•reanalyses <br />•Numerical Weather Predictors <br />•Global Climate Models