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University of Illinois Na Wind/Temperature Lidar in Urbana


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Instrument/Model Description

The University of Illinois Sodium (Na) Wind/Temperature Lidar was located at the Urbana Atmospheric Observatory (UAO) north of Urbana, Illinois at (40.167 N, 88.167 W) to take wind and temperature measurements between 1995 and 1998. The lidar was moved to the Starfire Optical Range (SOR) near Albuquerque, New Mexico (34.9639 N, 106.4619 W) in May 1998. Data has been taken at SOR since June 1998.

At UAO, the laser beam was projected to the zenith. The lidar was operated in one of two modes. One is 3-frequency mode with 900 laser shots per frequency; the other is 2-frequency mode with 1800 laser shots per frequency. The 3-frequency mode was used mostly at night to measure Na density, and both temperature and vertical wind. The 2-frequency mode was used mostly during the daytime to measure Na density and temperature only.

The lidar collected data between 10 and 196.6 km with a vertical resolution of 48 m collecting over 4096 range bins (48 m * 4096 bin = 196.6 km). The photon counts were summed every 20 range gates to get a vertical resolution of 960 m (20 * 48 m = 960 m).

Sodium densities are deduced between about 70 and 120 km, with a peak around 90 km. Reasonable temperatures and vertical winds can be found between about 80 and 110 km. The kindat=171001 data set consists of 37 altitudes between 75.489 km and 110.049 km, except for 3 periods in October 1996 where the 7.5 min bins consisted of 37 altitudes between 72.923 km and 106.306 km using both 2- and 3-frequency modes. Error bars are not determined for the sodium densities, which are related to the photocounts. The summed photocounts in the peak frequency are given after the background photocount, determined from the average between 120 and 150 km, is removed.

The error bars for the neutral temperature and vertical winds are standard deviations related to the number of summed photons. The error in the vertical wind is large, with a significant noise component. The largest error source is the photon noise. Uncertainties in the Pulsed Dye Amplifier (PDA) offset, the photomultiplier tube (PMT) saturation correction, and frequency jittering also contribute to the errors. For detailed error estimates, refer to Papen et al (1995).

Robert States, Jirong Yu and Xinzhao Chu collected the data, and Robert States was responsible for analyzing this data for his doctoral thesis.

Averaged 'mean day' data sets (kindats 17102 and 17103) of the averaged diurnal variation within every week or month were also made. They are obtained by averaging the data reported in KINDAT=17101 at every local hour with all data within the same local hour at different days. The weighting at different days are determined by an 8-week full width Hamming window centered at the 15th of each month. The assigned year for these monthly 'mean days' is 1997, since it was the middle of the observing period used. These are 'unsmoothed' data. The 'smoothed' data will become available later.

Summary plots of the mean Na density between 75 and 115 km for each 2-day period are provided, along with plots of the neutral temperature and vertical neutral wind.

Sodium Wind/Temperature Lidar References

Gardner, Chester S., Sodium resonance fluorescence lidar applications in atmospheric science and astronomy, Proceedings of the IEEE, 77, 1989, 408-418.
Gardner, Chester S. and George C. Papan, Mesospheric Na wind/temperature lidar, The Review of Laser Engineering, Vol. 23, No. 2, February 1995, pp.131-134, 1995 The Laser Society of Japan.
Papan, George C., William M. Pfenninger, and Dale M. Simonich, Sensitivity analysis of Na narrowband wind-temperature lidar systems, Applied Optics, Vol. 34, No. 3, 20 January 1995, pp.480-498.
Gardner, Chester S. and Michael J. Taylor, Observational limits for lidar, radar, and airglow imager measurements of gravity wave parameters, J. Geophys. Res. Vol. 103, No. D6, p.6427-6437, March 27, 1998.
Yu, Jirong, Robert States, Steve J. Franke, Chester S. Gardner, and Maura Hagan, Observations of tidal temperature and wind perturbations in the mesopause region above Urbana, IL (40N, 88W), Geophys. Res. Lett., Vol.24, No.10, pp.1207-1210, May 15, 1997.
States, Robert J. and Chester S. Gardner, Influence of the diurnal tide and thermospheric heat sources on the formation of mesospheric temperature inversion layers, Geophys. Res. Lett., Vol. 25, No. 9, pp.1483-1486, May 1, 1998.
States, Robert J., and Chester S. Gardner, Structure of the mesospheric Na layer at 40N latitude: seasonal and diurnal variations, J. Geophys. Res. Vol. 104, No. D9, pp.11783-11798, May 20, 1999.
States, Robert J., and Chester S. Gardner, Thermal structure of the mesopause region (80-105 km) at 40K latitude. Part I: Seasonal variations, J. Atmos. Sci., Vol. 57, No. 1, pp. 66-77, 1 January 2000.
States, Robert J., and Chester S. Gardner, Thermal structure of the mesopause region (80-105 km) at 40K latitude. Part II: Diurnal variations, J. Atmos. Sci., Vol. 57, No. 1, pp.78-92, 1 January 2000.

Summary Plots for University of Illinois Sodium Wind/Temperature Lidar at Urbana

Summary Plots for 'Mean Days' every week from the Sodium Wind/Temperature Lidar at Urbana

Summary Plots for 'Mean Days' every month from the Sodium Wind/Temperature Lidar at Urbana

-Revised 24 Aug 2005 by Barbara Emery