Arctic and Antarctic cloud properties from simultaneous lidar and spectral measurements

Spectral observations of Arctic and Antarctic clouds permit the determination of cloud effective particle sizes and optical depths by comparisons to model values of those properties. Both at the Atmospheric Radiation Measurement (ARM) program’s Barrow, Alaska site and at South Pole station, Fourier-transform interferometers observe clouds in the wavelength intervals between approximately 5 and 18 microns. Although these standalone measurements from spectral instruments can yield cloud microphysical properties, additional information from lidar provides useful information about the vertical extent of clouds being modeled. We examine the simultaneous lidar and spectral data from both Barrow and South Pole, both to obtain cloud properties (optical depth, particle size) by the use of both instruments, and to compare values of cloud properties (cloud base height) which can be independently obtained from data taken from either instrument. The examination of these datasets, in the course of time, can produce climatologies of cloud properties at the two sites, and also quantify the radiative impact of atmospheric phenomena particular to the high latitudes, such as blowing snow, diamond-dust, and polar stratospheric clouds (PSCs).