From August 2012 to February 2013 a High Resolution Spectral Lidar (HSRL; 532 nm) was deployed at that National University of Singapore near a NASA Micro Pulse Lidar NETwork (MPLNET; 527 nm) site. A primary objective of the MPLNET lidar project is the production and dissemination of reliable Level 1 measurements and Level 2 retrieval products. This paper characterizes and quantifies error in Level 2 aerosol optical property retrievals conducted through inversion techniques that derive backscattering and extinction coefficients from MPLNET elastic single-wavelength datasets. MPLNET Level 2 retrievals for aerosol optical depth and extinction/backscatter coefficient profiles are compared with corresponding HSRL datasets, for which the instrument collects direct measurements of each using a unique optical configuration that segregates aerosol and cloud backscattered signal from molecular signal. The intercomparison is performed, and error matrices reported, for lower (0-5km) and the upper (>5km) troposphere, respectively, to distinguish uncertainties observed within and above the MPLNET instrument optical overlap regime.
Z. Mariani, K. Strong, M. Wolff, P. Rowe, V. Walden, P. Fogal, T. Duck, G. Lesins, D. Turner, C. Cox, E. Eloranta, J. Drummond, C. Roy, R. Lachance, D. Hudak, I. Lindenmaier
The Extended-range Atmospheric Emitted Radiance Interferometer (E-AERI) is a moderate resolution (1 cm−1) Fourier
transform infrared spectrometer for measuring the absolute downwelling infrared spectral radiance from the atmosphere between 400 and 3000 cm−1. The extended spectral range of the instrument permits monitoring of the 400–550 cm−1 (20–25 μm) region, where much of the infrared surface cooling currently occurs in the dry air of the Arctic. The E-AERI provides information about radiative balance, trace gases, and cloud properties in the Canadian high Arctic. The instrument was installed at the Polar Environment Atmospheric Research Laboratory (PEARL) Ridge Lab at Eureka, Nunavut, in October 2008. Measurements are taken every seven minutes year-round (precipitation permitting), including polar night when the solar-viewing spectrometers are not operated. A similar instrument, the University of Idaho’s Polar AERI (P-AERI), was installed at the Zero-altitude PEARL Auxiliary Laboratory (0PAL), 15 km away from the Ridge Lab, from March 2006 to June 2009. During the period of overlap, these two instruments provided calibrated radiance measurements from two different altitudes. Retrievals of total columns of various trace gases are being evaluated using a prototype version of the retrieval algorithm SFIT2 modified to analyze emission features. In contrast to solar absorption measurements of atmospheric trace gases, which depend on sunlit clear-sky conditions, the use of emission spectra allows measurements year-round (except during precipitation events or when clouds are present). This capability allows the E-AERI to provide temporal coverage throughout the four months of polar night and to measure the radiative budget throughout the entire year. This presentation will describe the new E-AERI instrument, its performance evaluations, and clear sky vs. cloudy measurements.
The University of Wisconsin High Spectral Resolution Lidar (UW HSRL) produces direct measurements of cloud and aerosol optical depth, extinction cross section, backscatter cross section, and backscatter phase
function. The HSRL uses a multietalon interferometer to separate the backsctter return into a component due to particle scattering and a component due to scattering from air molecules. The molecular backscatter component is affected by extinction but not by particle backscatter. Because the molecular backscatter cross section is determined by the known atmospheric density, the atmospheric extinction can be directly calculated from the measured decrease in molecular backscatter signal with range. The
separation of aerosol from molecular scattering is possible because the backscatter component from air is Doppler-broadened by the thermal yelocities
of the molecules, while the backscatter from more massive, slower moving particles remains spectrally unbroadened. Although the HSRL was originally designed for airborne nadir observation of boundary layer aerosol optical properties, increases in transmitted power, receiver improvements, and modified calibration techniques have allowed it to measure cirrus cloud optical properties. A continuously pumped, Q-switched, 4 kHz pulse repetition frequency, injection seeded, frequency doubled Nd:YAG laser, still under development, has recently been installed and has reduced cirrus cloud measurement averaging times by a factor of '-10.
Conference Committee Involvement (4)
Lidar Remote Sensing for Environmental Monitoring VIII
29 August 2007 | San Diego, California, United States
Lidar Remote Sensing for Environmental Monitoring VI
2 August 2005 | San Diego, California, United States
Lidar Remote Sensing for Environmental Monitoring IV
3 August 2003 | San Diego, California, United States
Lidar Remote Sensing for Industry and Environment Monitoring III
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