ALASKA-95

The Cloud Lidar System (CLS) was an airborne lidar system that operated on the ER-2 aircraft. It measured lidar backscatter to determine the height structure of clouds, cloud thickness, and other cloud properties. CLS was also used to determine aerosol properties. It used a Nd-YAG operating at 1064 and 532 nm and had a pulse repetition frequency of 10 Hz. CLS had a horizontal resolution of 20 m and a vertical sampling resolution of 7.5 m.

The Aerodynamic Particle Sizer (APS) is an in situ spectrometer manufactured by TSI Instruments. APS measures aerodynamic particles in the 0.5-20 μm size range. It also measures the light-scattering intensity of the particles in the 0.37-20 μm optical size range. APS provides particle size distributions for 52 channels at a typical sampling time of 1 second. It uses a laser diode operating at 655 nm and has a size resolution of 0.02 μm at 1 μm. APS can be deployed on aircraft, ships, or ground-based platforms.

The MODIS Airborne Simulator (MAS) is an airborne multispectral spectrometer designed to simulate the satellite instrument Moderate-Resolution Imaging Spectrometer (MODIS). MAS operates across 50 spectral channels in the 0.55 to 14.2 μm range to provide high-resolution imagery of clouds and surface features. MAS has a horizontal spatial resolution of 50 m and a swath width of about 36 km at an altitude of 20 km at nadir. It has a scan rate of 6.25 Hz with each scan line containing 716 pixels.

The Scanning High-resolution Interferometer Sounder (S-HIS) is an airborne cross-track scanning interferometer developed by the Space Science and Engineering Center at the University of Wisconsin-Madison. It measures the emitted thermal radiation between 3.3 and 18 microns at high spectral resolution. These measurements can be used to derive atmospheric profiles of temperature and water vapor in clear-sky conditions. S-HIS has a spatial resolution of 2 km and a swath width of 40 km at an altitude of 20 km at nadir. It has a sampling frequency of 0.5 s and an absolute radiance accuracy of 0.2 K.

The Millimeter-wave Imaging Radiometer (MIR) was a passive airborne cross-track scanning radiometer developed by NASA. MIR measured brightness temperature across nine channels and was used for clouds, precipitation, and atmospheric water vapor studies. MIR operated near and around the following frequencies: 89, 150, 183, 220, and 325 GHz. It had an angular swath of 100 degrees and a sampling frequency of 3 seconds. MIR typically operated on NASA ER-2 aircraft before its retirement.