Description: Future flight vehicles will be required to emit lower and potentially different types of gases and particles in order to be more environmentally responsible. Particles emitted from jet turbines serve as cloud nuclei, and changes in their microphysical properties will impact upper level cloud formation, including contrails, which represents a major impact of aviation emissions on the environment and atmospheric radiation balance. Investigations into the impacts of current and future aviation emissions must determine any changes in the degree to which emissions affect contrail formation, cirrus cloud formation, and their evolution over time. This project seeks to develop an instrument suitable for in-flight, low-pressure measurements of the ice forming properties of particles emitted from jet engines, building on existing continuous flow diffusion chamber (CFDC) technology. The CFDC measures ice nucleating particles (INP) by exposing them to a region of controlled temperature and supersaturation and measuring ice crystals that may form. The CFDC approach is well suited for aircraft measurements because it is a fast measurement, however current technology is limited to laboratory studies due to the physical size and power requirements of the instrument. Smaller, portable versions of the CFDC are not yet commercially available, nor do they have sufficient cooling power to operate at conditions needed for studying contrail and cirrus formation. We will develop a CFDC-type instrument that uses newly developed flexible thermal electric devices to overcome existing limitations in that it will require less power, use smaller cooling system hardware that is more suitable for aircraft operation, and allow for the reduction of the physical size of the measurement chamber. Our goal is to produce the first commercial instrument capable of measuring INP in contrail and cirrus conditions at low pressure from a research aircraft, and deliver this prototype instrument to NASA.

Benefits: Applications include NASA's Advanced Air Vehicles Program, which has the goal of enabling new aircraft to "fly...cleaner, quieter, and more efficiently", which in turn requires minimization of aviation impacts on the environment. The technology also has applications to the Earth Science Research Program by advancing Earth System Science to meet the challenges of environmental change. Examples of relevant past airborne missions include ND-MAX, ACCESS II, and ACCESS (aeronautics) and ACTIVATE, IMPACTS, and CAMP2Ex (earth system science).

Applications include university-led research focused on understanding ice cloud formation and evolution and government-led airborne research focused on similar topics, both domestically and internationally. In addition to airborne measurements the instrument would have laboratory applications to allow in-depth study of important aerosol types and potential use in weather modification work.