Forcing radiative instantaneous

FIGURE 14.22 Model-calculated percentage (a) increase in Os (zonal average) in July and (b) the corresponding contributions to instantaneous radiative forcing calculated as a function of latitude and altitude from preindustrial times to the present (adapted from Chalita et al., 1996). 

In Eqs. (S) and (T), [gas] and [ref] represent the time-dependent concentrations of the gas of interest and the reference gas, respectively, which are assumed to decay with characteristic lifetimes or response times after the instantaneous injection of the pulse, and ax (units of W m-2 per ppb or ppm) is the radiative forcing of the gas or reference per unit increase in their atmospheric concentrations. The value of ax is assumed to be time-independent. 

An estimate of the instantaneous radiative forcing AFi by a nonabsorbing aerosol in the low... 

Radiative forcing defined as a change in the energy flux at the tropopause is referred to as instantaneous forcing (Figure 23.10a). The adjusted radiative forcing, which is the measure now commonly used, is the radiative forcing at the top of the atmosphere (TOA) in which the stratospheric temperature profile is allowed to adjust to the perturbation and... 

FIGURE 23.10 Assumptions used in calculating (a) AF , the instantaneous radiative forcing (b) AFa, the adjusted radiative forcing (c) AT0, the surface temperature response with no feedbacks and (d) AT, the surface temperature response with feedbacks (Hansen et al. 1997). (Reprinted by permission of American Geophysical Union.)... 

Global warming potential of a well-mixed gas is defined as the time-integrated commitment to radiative forcing from the instantaneous release of 1 kg of trace gas expressed relative to that from the release of 1 kg of C02. 

The subscript 0 refers to the no-feedback case. The subscript 1 refers to the instantaneous forcing with no feedbacks. (Note that surface temperature changes would be about one to four times larger if climate feedbacks were included The changes in radiative properties used here are meant to be illustrative and do not necessarily represent actual or projected changes.)... 

---