Table 1 Direct, instantaneous, unadjusted shortwave radiative forcing by methane (in W/m2) at three atmospheric levels under RTMIP experimental protocol (2).

Column-labeled RTMIP shows original RTMIP results (2); columns labeled 2000, 2004, 2008, 2012, and Jovian+2012 show forcings computed using the HITRAN 2000 (21), 2004 (30), 2008 (22), and 2012 (10) databases out to 12,000 cm−1 (see Materials and Methods), and the Jovian empirical methane parameterization including parametric uncertainty (2-σ, in parentheses) (9) combined with HITRAN 2012 out to 25,000 cm−1 (see Materials and Methods). Rows with units in the Δ column give the differences in forcings relative to the HITRAN 2000 values in absolute and percentage units.

LevelΔRTMIP2000200420082012Jovian+2012
TOA+0.09+0.096+0.098+0.097+0.098+0.099 ± (0.0)
W/m2+0.002+0.002+0.002+0.003
%+2.064+1.738+2.510+3.349
Tropopause−0.13−0.127−0.132−0.132−0.132−0.132 ± (2.6 × 10−8)
W/m2−0.005−0.005−0.005−0.005
%+4.211+3.927+3.978+3.636
Surface−0.55−0.574−0.589−0.588−0.590−0.594 ± (1.6 × 10−8)
W/m2−0.015−0.014−0.017−0.020
%+2.673+2.452+2.889+3.495