Abstract

During the forthcoming decade and beyond there will be a plethora of global space-based active and passive measurements of cirrus and ice cloud. These measurements will be across the electromagnetic spectrum, from the ultra-violet to the far-infrared, through to the sub-millimeter, where there are no current radiance observations in the latter spectral regions. To take advantage of these unprecedented high-resolution and spectral-like measurements, ice crystal models are required that are physically consistent throughout the electromagnetic spectrum, and which are consistent with microphysics assumptions in weather and climate models. Achieving such physical consistency between ice crystal models, remote-sensing, and large-scale models to meet the challenges posed by the forthcoming measurements over the next decade or so is problematic. However, it is necessary to overcome this difficulty to improve the predictive quality of weather and climate models to address extreme weather events and climate change, respectively. However, cirrus and ice cloud types consist of ice crystals that vary considerably both in shape and size between the cloud top and bottom. Not surprisingly, with such variability in the shapes and sizes, obtaining models that are coherent across the spectrum while at the same time being consistent with microphysics assumptions in weather and climate models is difficult. In this talk, to address the above issues, an approach using an ensemble model of cirrus ice crystals to predict consistently the observed radiative properties of cirrus from the ultra-violet to the far-infrared will be discussed using aircraft and satellite-based high-resolution radiance measurements. In this analysis, different shapes of the particle size distribution are utilized that are consistent with a weather and climate model, remote-sensing, and with an in-situ mass power law. Here, the need for improved simultaneous in-situ and aircraft remote-sensing spectral characterization of cirrus across the electromagnetic spectrum will be emphasized. Moreover, an example of the development of a new ice crystal model that follows in-situ ice crystal mass and area power laws, which are consistent with a weather and climate model is described, with some preliminary results, to help address the radiative issues.