Sampling Strategies to Optimize Coincident Remote Sensing and In Situ Cloud and Precipitation Observations from Multiple Aircraft

The combination of simultaneous, collocated aircraft in situ measurements and remote sensing data at multiple wavelengths is of tremendous value in physical process studies but is hard to obtain in practice. Appropriate multiaircraft and multisensor resources for a given project must be coupled with agile mission support (people and tools) and close coordination with the Federal Aviation Administration to implement successfully. Obtaining closely coordinated in situ and remote sensing measurements was key to meeting the science objectives for the NASA Investigation of Microphysics and Precipitation for Atlantic Coast-Threatening Snowstorms (IMPACTS), and it required a team effort. IMPACTS flew a complementary suite of remote sensing and in situ instruments in three 6-week deployments on the NASA ER-2 and P-3 aircraft to provide observations critical to understanding the mechanisms of snowband formation, organization, and evolution. The collocated IMPACTS data subset encompassed 106 flight legs during 22 storms, and it included over 21 h where the ER-2 and P-3 were only up to 5 min and 4 km apart. This unique dataset on winter storm conditions in the Northeast and Midwest United States provides a wealth of information, which will have lasting value for the community. This paper explains how the science team, engineers, aircrews, and NASA mission support accomplished the measurement goals and key aspects of the IMPACTS coordinated dataset. Future field campaigns with similar science applications can maximize their flight hours by leveraging the lessons learned from IMPACTS coordination. SIGNIFICANCE STATEMENT: Winter storms feature poorly understood and predicted snowbands where precipitation is concentrated. NASA funded a multiyear field campaign using complementary aircraft to study these bands over the United States. The project employed two aircraft in a stacked configuration: one plane flew within storms, similar to Hurricane Hunters, using cloud probes to collect in situ measurements, while the other plane flew above with advanced radars and other instruments to simulate satellite observations. By flying coordinated patterns perpendicular to snowbands, the project collected 21 h of collocated data of ice crystals and storm structure. This data will improve both space-based snowfall measurement capabilities and model-based snowfall forecasts through enhanced understanding of the complex processes within winter storms.