Sampling the composition of cirrus ice residuals

This review addresses what is currently known about the abundance, size and composition of cirrus-forming particles. We review aircraft-based field studies which have either collected cirrus ice residuals for off-line analysis or determined their size, composition and other properties in situ by capturing ice crystals and sublimating/removing the condensed phase water. This review is predominantly restricted to cirrus clouds. Limited comparisons are made to other ice-containing (e.g., mixed-phase) cloud types. The findings of recent reviews on laboratory measurements that mimic upper tropospheric cirrus formation are briefly summarized. The limitations of the current state of the art in cirrus ice residual studies are outlined. Important ancillary measurements and how they are integrated with ice residual data are also presented. Concluding statements focus on the need for specific instrumentation and future studies.