TSI Integrating Nephelometers are designed specifically for studies of direct radiative forcing of the Earth’s climate by aerosol particles, or studies of ground-based or airborne atmospheric visual air quality in clean areas. They may also be used as an analytical detector for aerosol particles whenever the parameter of interest is the light-scattering coefficient of the particles after a pretreatment step, such as heating, humidification, or segregation by size. The light-scattering coefficient is a highly variable aerosol property. Integrating Nephelometers measure the angular integral of light scattering that yields the quantity called the aerosol scattering coefficient, which is used in the Beer-Lambert Law to calculate total light extinction.
Twin Otter (DOE)
The utility of millimeter-wave radars have been successfully used for cloud sensing and cloud microphysical studies. Studies of the impact of cloud feedbacks on the earth's radiation budget have underscored the importance of having a means of measuring the vertical distribution of clouds. Millimeter-wave radars can provide this information under most conditions, with high resolution, using a relatively compact system.
The Airborne Cloud Radar (ACR) for profiling cloud vertical structure was developed by the Jet Propulsion Laboratory and the University of Massachusetts in 1996. It is a W-band (95 GHz) polarimetric Doppler radar designed as a prototype airborne facility for the development of the 94 GHz Cloud Profiling Radar (CPR) for NASA CloudSat mission.
The ACR is a third-generation millimeter-wave cloud radar. While adopting the well tested techniques used by its predecessors, ACR also has a number of new features including an internal calibration loop, frequency agility, digital I and Q demodulation, digital matched filtering, and a W-band low-noise amplifier.