Measurements of gaseous (NO, NOy, SO2, HONO) and ice particle concentrations in young contrails in primary and secondary wakes of aircraft of different sizes (B737, A319, A340, A380) are used to investigate ice particle formation behind aircraft. The gas concentrations are largest in the primary wake and decrease with increasing altitude in the secondary wake, as expected for passive trace gases and aircraft-dependent dilution. In contrast, the measured ice particle concentrations were found larger in the secondary wake than in the primary wake. The contrails contain more ice particles than expected for previous black carbon (soot) estimates. The ice concentrations may result from soot induced ice nucleation for a soot number emission index of 10^15 kg^-1. For a doubled ice particle concentration in young contrails, a contrail cirrus model computes about 60% increases of global radiative forcing by contrail cirrus because of simultaneous increases in optical depth, age and cover.
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机译：测量不同尺寸（B737，A319，A340，A380）飞机初级和次级尾流中年轻凝结尾迹中的气态（NO，NOy，SO2，HONO）和冰颗粒浓度，以调查飞机后面的冰粒形成情况。气体浓度在一次尾流中最大，并随着二次尾流高度的增加而降低，这是被动痕量气体和飞机稀释所预期的。相反，发现在次要尾流中测得的冰颗粒浓度比主要尾流中的大。凝结尾迹中的冰粒比以前的黑碳（烟灰）估计值要多。冰浓度可以由烟灰诱导的冰核化而产生，烟尘数发射指数为10 ^ 15 kg ^ -1。对于年轻的凝结尾迹中的冰粒浓度增加一倍的情况，由于光学深度，年龄和覆盖面的同时增加，凝结尾迹卷云模型计算出的凝结尾迹卷云使全球辐射强迫增加了约60％。
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