Fig. 1 | npj Climate and Atmospheric Science

Fig. 1

From: Mitigating the contrail cirrus climate impact by reducing aircraft soot number emissions

Fig. 1

Impact of a reduction in initial ice crystal number, as may be caused by reduced soot emissions, on global contrail cirrus properties. Relative change in contrail cirrus a in-cloud ice water content and b ice crystal volume radius at 240 hPa and absolute change in (c) total cover of contrail cirrus with an optical depth > 0.05 and d contrail cirrus net radiative forcing due to a 80% reduced initial ice crystal number (low minus present-day initial ice crystal number). Hatched areas indicate locations in which the difference is statistically significant at a 95% confidence level. e Frequency of contrail cirrus optical depth over Europe at 240 hPa when prescribing present-day (red), or low (blue) initial ice crystal number concentration. f Global net radiative forcing (RF), given as a fraction of the radiative forcing for the ‘present-day soot number scenario’, as a function of the initial ice particle number concentration of contrails, given as a fraction of the initial ice crystal number concentration for the ‘present-day soot number scenario’. Initial ice crystal numbers were reduced to 0.5, 0.2, and 0.1 of the present-day values. Vertical bars (horizontal lines) indicate the full range (90% of the range) of values obtained when calculating the reduction based on yearly means. The dashed line, indicating linearity, serves for comparison

Back to article page