Observations and observing systems are a primary focus of much of the research that is conducted in Atmospheric Science at UW. Developing new instruments and characterizing and understanding existing instruments is key to being able to use observations effectively in addressing relevant scientific questions. The department maintains laboratory facilities such as the Keck Aerosol Lab (Snider and Murphy) and the Cloud Physics Lab (French) that can be used to generate particles to challenge and calibrate aerosol and cloud probes that operate on mobile facilities or on the King Air Research Aircraft. Research also includes the development of new instruments for detailed in situ measurements of aerosol optical and chemical properties (Murphy) and cloud hydrometeor properties (French) and for broader scale remotely sensed characteristics of clouds and aerosol (Wang) using lidars and radars. The remote sensing group works to development algorithms utilizing measurements from multiple platforms (radar, lidar, radiometer) to better describe cloud and aerosol characteristics.