Description

The Cloud Radar System (CRS) is a 94 GHz, W-band polarimetric Doppler radar designed to operate aboard the NASA ER-2 high-altitude research aircraft or as a ground-based radar. Its very high frequency and short 3 mm wavelength make it very sensitive; perfect for cirrus cloud studies in particular as it has the ability to collect more detailed cloud and precipitation observations than traditional weather radars. Since CRS was specifically tailored to operate from the NASA ER-2 aircraft, the instrument is compact, does not require pilot operation, and can capture measurements useful for the validation of satellite estimates. The CRS is housed inside the tailcone of either ER-2 superpod, located in the mid-sections of the aircraft wings. Because the ER-2 flies at a 20 km altitude, within the lower stratosphere, CRS in located in close proximity with its targets, decreasing measurement effects that would occur at a larger distance. It can detect clouds and precipitation from flight level down to the surface. When CRS is operating airborne, its downward pointing beam takes profiles of radar reflectivity and Doppler velocity. Its polarimetric capabilities enable it to measure the horizontal and vertical dimensions of cloud and precipitation particles, revealing cloud microphysical properties and processes. The CRS can also effectively detect the intense signal returned by the ocean’s surface, making the ocean an ideal target for calibrating the instrument. The specialized capabilities of CRS make it very useful for observing cloud microphysics and dynamics. Observations by CRS and other instruments mounted on the ER-2 aircraft also provide important insight into cloud radiative properties impacting Earth’s global energy budget.

Measurements

Measures radar reflectivity, Doppler velocity, linear depolarization ratio, and differential reflectivity. The Doppler velocity values are corrected for the motion and orientation of the aircraft. CRS has two operation modes. When CRS operates in ER-2 mode, it can measure reflectivity, Doppler velocity, and linear depolarization ratio. When it operates in ground-based mode, it can operate with full polarimetric capabilities.

Applications

• Cloud and Precipitation Studies
• Cloud Microphysics and Dynamics
• Climate
• Global Energy Budget