Instruments:csl

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Colorado State University Lidar

Contents


Contact Persons

Web Sites

Acknowledgments

The Colorado State University sodium lidar is operated by the Colorado State University with support from the National Science Foundation. It is designated as a Ground Based Instrument (GBI) for the TIMED satellite mission, and so has additional support from CEDAR/TIMED NSF and NASA (National Aeronautics and Space Administration) funding.

Data Sets available in text form

Data Description

The Colorado State University (CSU) narrow-band sodium (Na) lidar is located at Fort Collins, Colorado at (40.59N, 105.14W), 1570 m above sea level. It was developed with CEDAR support and has been in operation since 1990. The sodium layer is located between about 70 and 120 km, with a peak near 92 km. At the end of 2001 at 92 km, the apex magnetic lat,lon coordinates were (49.61, -40.17), where the magnetic inclination and declination angles were 67.58 deg and 10.33 deg. The magnetic local time at 0 UT is 1612 MLT.

The centroid wavelength of the sodium D2 transition is at 589.158 nm, which corresponds to a centroid frequency of f0=5.0886E+14 Hz. The peak of the sodium D2a transition is located at fa=-0.6514 GHz relative to the centroid frequency.

The 2-frequency system is the simpler, backup system, where the cavity of the laser is tuned between fa and a second higher frequency, fc=0.1878 GHz above the centroid frequency f0. The sodium density is determined from the the signal intensity at fa, Sfa, normalized to Rayleigh scattering at a lower altitude, e.g., 30km, while the temperature can be determined from the ratio of the signal intensity, Sfc, received at fc to that at fa, Sfc/Sfa, for the 2-frequency operation.

The 3-frequency system uses an acoustic optic modulator (AOM) which shifts the frequency from fa where the continuous wave (cw) laser is locked to a lower frequency fl=-1.2814 GHz, and a higher frequency fh=-0.0214 GHz, relative to f0. With 3-frequency operation, the temperature and the line of sight (los) velocity are determined collectively from two intensity ratios: the ratio 0.5(Sfh+Sfl)/Sfa, which is mainly sensitive to temperature, and a second ratio of (Sfh-Sfl)/Sfa mainly sensitive to the los velocity.

The CSU lidar has two telescpes, so they can both be used and pointed in different directions to get concurrent observations of Na, temperature, and los winds that are reported in different kindats. The telescopes are often pointed 60 degrees in elevation to geographic north (azimuth=0 deg) and geographic east (azimuth=90 deg), in kindats=17011-2, where
Horizontal winds = los winds/cos(60) = 2*los winds
assuming zero vertical winds are stored in kindats 18011-2.

Up to the end of 2000, most observations were made during the night, and most were taken with 2-frequency operation using 1200 lidar shots per min. By the end of 2000, a total of 501 nights of temperature and sodium density data were taken and analyzed. The hourly, nightly and monthly mean profiles from 51 nights in 1993 are stored in kindats 17001, 17002 and 17003.

The nocturnal mean temperatures at 87+/-1.85 km for each night with 4 hours of data or longer were calculated from nightly mean photofiles directly, and from the mean of hourly averaged temperatures from 419 nights between 1990 and 1999. They were vertically smoothed by a running Hanning window with FWHM (Full Width at Half Maximum) of 3.7 km. The signal to noise ratio was better for the nightly mean photofiles obtained by averaging the photon files over the entire night before the temperatures were calculated. Therefore, this nightly mean temperature was defined to be the temperature.

The nocturnal mean temperatures at 87 km are provided for colleagues who wish to compare the measured OH airglow rotational temperatures. She and Lowe (1998) suggest that under normal conditions, the centroid of the OH layer is at 87 km and that the OH temperature can then be used as proxy for temperatures at 87 km. However, this proxy should be used with care, because under unusual conditions when the OH profile is highly disturbed, sometimes with the appearance of double peaks, the OH temperature may differ from the lidar temperature at 87 km in excess of 20 K.

Daytime observations are made using a Faraday filter which consists of a sodium atomic vapor cell in an imposed magnetic field between a pair of crossed polarizers. The broadband background sunlight is removed by the crossed polarizers. At the proper setting of vapor density in the Na cell and the imposed magnetic field, the received sodium light, linearly polarized after the first polarizer, has its polarization rotated by 90 deg and is retained. This technique has been used for both the 2-frequency system and the 3-frequency system to find daytime horizontal winds. Daytime lidar data in the CEDAR Database started in April 2002.

At present, the width of the range gates (code 126) is 150 m for the lidar observations. The lidar fires 3000 shots per minute (50/s), evenly divided among the frequencies used. Two minute observations are the shortest periods retained by the system, and these are usually summed over 1 UT hour (code 61) and smoothed in altitude using a Hanning window [Press et al., 1986] to give a vertical Full Width at Half Maximum (FWHM, code 4021) resolution of ~2 km and ~4 km, respectively for nighttime and daytime data. FWHM = # samples in range ave * width of range gate * cos(90-elevation) / 2, or 2.01 km for 31 samples, at 60 degree elevation angle, with 150 m gates. The vertical resolution and laser shots per minute varied in the past and may vary again in the future. In some cases higher resolution data may be available from the data providers, where the UT is the 2 min ending time.

For TIMED/CEDAR, the 3-frequency operation is intended, and a mean sodium density, neutral temperature, and neutral los wind are given for each telescope associated with a particular azimuth at 1.0 km intervals between 75 and 115 km at regular UT intervals (kindat 17011) and every night or day (kindat 17012), where the night or day average is computed from the interval averages weighted by the number of profiles used in each interval (code 415). Also included are measurement uncertainties calculated from the standard deviation of the photon noise present in the stated temporal and spatial resolution. The horizontal wind components (zonal or meridional) from the number of telescopes used are stored in kindats 18011 and 18012 for the UT interval and average values along with copies of the temperatures in those directions.

Three days of data will be available each month starting January 2002 for TIMED/CEDAR use. Other periods are available from the data providers and are listed at [csldates.html /instr/csldates.html]. The January through March 2002 data were revised in August 2002.

The physics behind and the technology of the 2-frequency operation can be found in She et al. (1992). Those who are interested in the technique should contact the data providers.

References

Key references for the technology of and the science derived from the Colorado State University (CSU) narrow-band sodium (Na) lidar are:

Press, W. H., Flannery, B. P., Teukolsky and W. T. Vetterling, "Numerical Recipes, the art of scientific computing", p. 425, The Cambridge University Press, 1986.
She, C. Y., H. Latifi, J. R. Yu, R. J. Alvarez II, R. E. Bills and C.S. Gardner, Two-Frequency Lidar Technique for Mesospheric Na Temperature Measurements, Geophys. Res. Lett., 17, 929-932, 1990.
She, C. Y., J. R. Yu, H. Latifi and R. E. Bills, High-Spectral-Resolution Fluorescence Lidar for Mesopheric Sodium Temperature Measurements, Appl. Opt., 31, 2095-2106, 1992.
Chen, H., C. Y. She and Eric Korevaar, Na Vapor Dispersive Faraday Filter, Opt. Lett. 18, 1019-1021, 1993.
She, C. Y., and J. R. Yu, Doppler-Free Saturation Fluorescence Spectroscopy of Na Atoms for Atmospheric Applications, Appl. Opt., 34, 1063-1075, 1995.
Yu, J. R. and C. Y. She, Climatology of a mid-latitude mesopause region observed by a lidar at Ft. Collins, CO (40.6N, 105W), J. Geophys. Res., 100, 7441-7452, 1995.
She, C. Y. and U. von Zahn, The concept of two-level mesopause: Support through new lidar observation, J. Geophys. Res., 103, 5855-5863, 1998.
She, C. Y., S. W. Thiel and D. A. Krueger, Observed episodic warming at 86 and 100 km between 1990 and 1997: Effects of Mount Pinatubo eruption, Geophys. Res. Lett., 25, 497-500, 1998.
Williams, B. P., C. Y. She, and R. G. Roble, Seasonal climatology of the nighttime tidal perturbation of temperature in the midlatitude mesopause region, Geophys. Res. Lett., 25, 3301 - 3304, 1998.
She, C. Y., and R. P. Lowe, Seasonal temperature variations in the mesopause region at mid-latitude: comparison of lidar and hydroxyl rotational temperatures using WINDII/UARD OH height profiles, J. Atmo. Solar-Terr. Physics, 60, 1573-1583, 1998.
Krueger, D. A., and C. Y. She, Observed "long-term" temperature change in a midlatitude mesopause region in response to external perturbation, Earth, Planets and Space, 51, 809-814, 1999.
Chen, S. S., Z. L. Hu, M. A. White, D. A. Krueger and C. Y. She, Lidar observations of seasonal variation of diurnal mean temperature in the mesopause region over Fort Collins, CO (41oN, 105oW), J. Geophys. Res., 105, 12,371-12,379, 2000.


1993 Summary Nightly Hourly Plots for Colorado State Lidar

At 0.5 km intervals between 70 and 119 km, a mean temperature and sodium density are plotted every hour. There are 4 areas in the summary plots for each of 2 nights of data. The top plots show the neutral temperature as a function of height and time, while the bottom plots show the log of the sodium density.

Summary Nighttime Ave Tn at 87 km for Colorado State Lidar

Summary 3-Frequency Night and Day Plots for Colorado State Lidar

At 1.0 km intervals between 75 and 115 km, a mean sodium density, temperature and mean horizontal wind are plotted every hour. There are 4 areas in the summary plots for each night/day of data. The top plots show the log of the sodium density and the neutral temperature as a function of height and time from a combination of the two telescopes if present, while the bottom plots show the neutral horizontal winds from one or both of the telescopes. Local midnight is at 0701 UT. The plots go from 0 UT to 27 UT, so there can be data up to 3 UT on the day after the date listed in the plot.

2002

2003

2004

2005

2006 (old plots of old data)

  1. 05 Jan 2006 All data for this period
  2. 06 Jan 2006 All data for this period
  3. 07 Jan 2006 All data for this period
  4. 11 Feb 2006 All data for this period
  5. 12 Feb 2006 All data for this period
  6. 13 Feb 2006 All data for this period
  7. 14 Feb 2006 All data for this period
  8. 21 Feb 2006 All data for this period
  9. 22 Feb 2006 All data for this period
  10. 23 Feb 2006 All data for this period
  11. 24 Feb 2006 All data for this period
  12. 31 Mar 2006 All data for this period
  13. 03 Apr 2006 All data for this period
  14. 08 Apr 2006 All data for this period
  15. 09 Apr 2006 All data for this period
  16. 22 Jul 2006 All data for this period
  17. 23 Jul 2006 All data for this period
  18. 28 Jul 2006 All data for this period
  19. 29 Jul 2006 All data for this period
  20. 22 Aug 2006 All data for this period
  21. 29 Aug 2006 All data for this period
  22. 30 Aug 2006 All data for this period
  23. 03 Sep 2006 All data for this period
  24. 04 Sep 2006 All data for this period
  25. 05 Sep 2006 All data for this period
  26. 06 Sep 2006 All data for this period
  27. 13 Oct 2006 All data for this period
  28. 14 Oct 2006 All data for this period
  29. 23 Oct 2006 All data for this period
  30. 24 Oct 2006 All data for this period
  31. 27 Oct 2006 All data for this period
  32. 28 Oct 2006 All data for this period
  33. 29 Oct 2006 All data for this period
  34. 01 Nov 2006 All data for this period
  35. 02 Nov 2006 All data for this period
  36. 03 Nov 2006 All data for this period
  37. 08 Nov 2006 All data for this period
  38. 09 Nov 2006 All data for this period
  39. 30 Nov 2006 All data for this period
  40. 01 Dec 2006 All data for this period
  41. 04 Dec 2006 All data for this period
  42. 05 Dec 2006 All data for this period
  43. 08 Dec 2006 All data for this period
  44. 09 Dec 2006 All data for this period
  45. 10 Dec 2006 All data for this period

2002 (new plots for old data) New.jpg

These plots are of a 'campaign' period of 1-6 days where the temperatures are in a contour plot, while the horizontal winds are plotted on top of the contour with eastward towards increasing time and northward towards increasing height. The sodium densities are not plotted, but are in a larger area than the other parameters in height and time. For these plots, 'duplicate' hours at the transitions between day and night files are averaged for simplicity. Some short periods were combined and some long periods were broken up.

  1. 2002 days 008-009 or moda 0108-0109 All data for this period
  2. 2002 days 011-014 or moda 0111-0114 All data for this period
  3. 2002 days 022-022 or moda 0122-0122 All data for this period
  4. 2002 days 027-027 or moda 0127-0127 All data for this period
  5. 2002 days 032-032 or moda 0201-0201 All data for this period
  6. 2002 days 034-035 or moda 0203-0204 All data for this period
  7. 2002 days 037-038 or moda 0206-0207 All data for this period
  8. 2002 days 046-046 or moda 0215-0215 All data for this period
  9. 2002 days 058-058 or moda 0227-0227 All data for this period
  10. 2002 days 076-076 or moda 0317-0317 All data for this period
  11. 2002 days 079-079 or moda 0320-0320 All data for this period
  12. 2002 days 083-083 or moda 0324-0324 All data for this period
  13. 2002 days 087-090 or moda 0328-0331 All data for this period
  14. 2002 days 098-098 or moda 0408-0408 All data for this period
  15. 2002 days 102-103 or moda 0412-0413 All data for this period
  16. 2002 days 108-108 or moda 0418-0418 All data for this period
  17. 2002 days 112-115 or moda 0422-0425 All data for this period
  18. 2002 days 119-120 or moda 0429-0430 All data for this period
  19. 2002 days 123-123 or moda 0503-0503 All data for this period
  20. 2002 days 125-127 or moda 0505-0507 All data for this period
  21. 2002 days 142-143 or moda 0522-0523 All data for this period
  22. 2002 days 145-146 or moda 0525-0526 All data for this period
  23. 2002 days 150-153 or moda 0530-0602 All data for this period
  24. 2002 days 157-163 or moda 0606-0612 All data for this period
  25. 2002 days 198-199 or moda 0717-0718 All data for this period
  26. 2002 days 205-205 or moda 0724-0724 All data for this period
  27. 2002 days 210-212 or moda 0729-0731 All data for this period
  28. 2002 days 221-224 or moda 0809-0812 All data for this period
  29. 2002 days 245-248 or moda 0902-0905 All data for this period
  30. 2002 days 257-260 or moda 0914-0917 All data for this period
  31. 2002 days 280-283 or moda 1007-1010 All data for this period
  32. 2002 days 285-285 or moda 1012-1012 All data for this period
  33. 2002 days 308-311 or moda 1104-1107 All data for this period
  34. 2002 days 320-323 or moda 1116-1119 All data for this period
  35. 2002 days 347-350 or moda 1213-1216 All data for this period
  36. 2002 days 353-354 or moda 1219-1220 All data for this period
  37. 2002 days 361-361 or moda 1227-1227 All data for this period

2003 (new plots for old data) New.jpg

  1. 2003 days 003-003 or moda 0103-0103 All data for this period
  2. 2003 days 019-021 or moda 0119-0121 All data for this period
  3. 2003 days 029-030 or moda 0129-0130 All data for this period
  4. 2003 days 038-039 or moda 0207-0208 All data for this period
  5. 2003 days 042-042 or moda 0211-0211 All data for this period
  6. 2003 days 050-052 or moda 0219-0221 All data for this period
  7. 2003 days 064-068 or moda 0305-0309 All data for this period
  8. 2003 days 072-073 or moda 0313-0314 All data for this period
  9. 2003 days 085-085 or moda 0326-0326 All data for this period
  10. 2003 days 099-101 or moda 0409-0411 All data for this period
  11. 2003 days 103-104 or moda 0413-0414 All data for this period
  12. 2003 days 106-107 or moda 0416-0417 All data for this period
  13. 2003 days 132-134 or moda 0512-0514 All data for this period
  14. 2003 days 136-137 or moda 0516-0517 All data for this period
  15. 2003 days 141-141 or moda 0521-0521 All data for this period
  16. 2003 days 149-149 or moda 0529-0529 All data for this period
  17. 2003 days 159-160 or moda 0608-0609 All data for this period
  18. 2003 days 172-174 or moda 0621-0623 All data for this period
  19. 2003 days 183-184 or moda 0702-0703 All data for this period
  20. 2003 days 186-187 or moda 0705-0706 All data for this period
  21. 2003 days 189-192 or moda 0708-0711 All data for this period
  22. 2003 days 196-196 or moda 0715-0715 All data for this period
  23. 2003 days 203-203 or moda 0722-0722 All data for this period
  24. 2003 days 225-229 or moda 0813-0817 All data for this period
  25. 2003 days 232-233 or moda 0820-0821 All data for this period
  26. 2003 days 261-263 or moda 0918-0920 All data for this period
  27. 2003 days 264-269 or moda 0921-0926 All data for this period
  28. 2003 days 269-275 or moda 0926-1002 All data for this period
  29. 2003 days 278-278 or moda 1005-1005 All data for this period
  30. 2003 days 282-283 or moda 1009-1010 All data for this period
  31. 2003 days 290-292 or moda 1017-1019 All data for this period
  32. 2003 days 317-320 or moda 1113-1116 All data for this period
  33. 2003 days 322-323 or moda 1118-1119 All data for this period
  34. 2003 days 350-354 or moda 1216-1220 All data for this period

2004 (new plots for old data) New.jpg

  1. 2004 days 038-038 or moda 0207-0207 All data for this period
  2. 2004 days 044-048 or moda 0213-0217 All data for this period
  3. 2004 days 056-057 or moda 0225-0226 All data for this period
  4. 2004 days 068-070 or moda 0308-0310 All data for this period
  5. 2004 days 077-079 or moda 0317-0319 All data for this period
  6. 2004 days 086-086 or moda 0326-0326 All data for this period
  7. 2004 days 090-093 or moda 0330-0402 All data for this period
  8. 2004 days 105-105 or moda 0414-0414 All data for this period
  9. 2004 days 117-119 or moda 0426-0428 All data for this period
  10. 2004 days 124-127 or moda 0503-0506 All data for this period
  11. 2004 days 132-132 or moda 0511-0511 All data for this period
  12. 2004 days 152-153 or moda 0531-0601 All data for this period
  13. 2004 days 158-158 or moda 0606-0606 All data for this period
  14. 2004 days 160-160 or moda 0608-0608 All data for this period

2005 (new plots for old data) New.jpg

  1. 2005 days 008-008 or moda 0108-0108 All data for this period
  2. 2005 days 020-025 or moda 0120-0125 All data for this period
  3. 2005 days 129-129 or moda 0509-0509 All data for this period
  4. 2005 days 133-133 or moda 0513-0513 All data for this period
  5. 2005 days 135-135 or moda 0515-0515 All data for this period
  6. 2005 days 137-138 or moda 0517-0518 All data for this period
  7. 2005 days 140-143 or moda 0520-0523 All data for this period
  8. 2005 days 147-148 or moda 0527-0528 All data for this period
  9. 2005 days 156-159 or moda 0605-0608 All data for this period
  10. 2005 days 169-170 or moda 0618-0619 All data for this period
  11. 2005 days 192-195 or moda 0711-0714 All data for this period
  12. 2005 days 230-230 or moda 0818-0818 All data for this period
  13. 2005 days 238-242 or moda 0826-0830 All data for this period
  14. 2005 days 242-247 or moda 0830-0904 All data for this period
  15. 2005 days 262-262 or moda 0919-0919 All data for this period
  16. 2005 days 273-275 or moda 0930-1002 All data for this period
  17. 2005 days 297-300 or moda 1024-1027 All data for this period
  18. 2005 days 323-326 or moda 1119-1122 All data for this period

2006 New.jpg

The 2006 data were replaced in January 2011 to correct pointing errors.

  1. 2006 days 005-007 or moda 0105-0107 All data for this period
  2. 2006 days 042-045 or moda 0211-0214 All data for this period
  3. 2006 days 052-056 or moda 0221-0225 All data for this period
  4. 2006 days 090-090 or moda 0331-0331 All data for this period
  5. 2006 days 093-093 or moda 0403-0403 All data for this period
  6. 2006 days 098-099 or moda 0408-0409 All data for this period
  7. 2006 days 203-204 or moda 0722-0723 All data for this period
  8. 2006 days 209-210 or moda 0728-0729 All data for this period
  9. 2006 days 234-234 or moda 0822-0822 All data for this period
  10. 2006 days 241-242 or moda 0829-0830 All data for this period
  11. 2006 days 246-249 or moda 0903-0906 All data for this period
  12. 2006 days 286-287 or moda 1013-1014 All data for this period
  13. 2006 days 296-297 or moda 1023-1024 All data for this period
  14. 2006 days 300-302 or moda 1027-1029 All data for this period
  15. 2006 days 305-307 or moda 1101-1103 All data for this period
  16. 2006 days 312-313 or moda 1108-1109 All data for this period
  17. 2006 days 334-335 or moda 1130-1201 All data for this period
  18. 2006 days 338-339 or moda 1204-1205 All data for this period
  19. 2006 days 342-343 or moda 1208-1209 All data for this period

2007 New.jpg

  1. 2007 days 015-020 or moda 0115-0120 All data for this period
  2. 2007 days 063-064 or moda 0304-0305 All data for this period
  3. 2007 days 104-105 or moda 0414-0415 All data for this period
  4. 2007 days 118-119 or moda 0428-0429 All data for this period
  5. 2007 days 166-166 or moda 0615-0615 All data for this period
  6. 2007 days 203-203 or moda 0722-0722 All data for this period
  7. 2007 days 205-205 or moda 0724-0724 All data for this period
  8. 2007 days 221-221 or moda 0809-0809 All data for this period
  9. 2007 days 223-224 or moda 0811-0812 All data for this period
  10. 2007 days 250-251 or moda 0907-0908 All data for this period
  11. 2007 days 254-256 or moda 0911-0913 All data for this period
  12. 2007 days 282-284 or moda 1009-1011 All data for this period
  13. 2007 days 297-299 or moda 1024-1026 All data for this period
  14. 2007 days 331-331 or moda 1127-1127 All data for this period

2008 New.jpg

  1. 2008 days 014-015 or moda 0114-0115 All data for this period
  2. 2008 days 023-025 or moda 0123-0125 All data for this period
  3. 2008 days 027-027 or moda 0127-0127 All data for this period
  4. 2008 days 050-051 or moda 0219-0220 All data for this period
  5. 2008 days 104-106 or moda 0413-0415 All data for this period
  6. 2008 days 138-139 or moda 0517-0518 All data for this period
  7. 2008 days 151-151 or moda 0530-0530 All data for this period
  8. 2008 days 160-160 or moda 0608-0608 All data for this period
  9. 2008 days 182-182 or moda 0630-0630 All data for this period
  10. 2008 days 192-193 or moda 0710-0711 All data for this period
  11. 2008 days 207-207 or moda 0725-0725 All data for this period
  12. 2008 days 213-213 or moda 0731-0731 All data for this period
  13. 2008 days 241-243 or moda 0828-0830 All data for this period
  14. 2008 days 275-276 or moda 1001-1002 All data for this period
  15. 2008 days 288-290 or moda 1014-1016 All data for this period
  16. 2008 days 297-299 or moda 1023-1025 All data for this period
  17. 2008 days 324-325 or moda 1119-1120 All data for this period
  18. 2008 days 329-330 or moda 1124-1125 All data for this period
  19. 2008 days 345-346 or moda 1210-1211 All data for this period

2009 New.jpg

  1. 2009 days 019-021 or moda 0119-0121 All data for this period
  2. 2009 days 055-056 or moda 0224-0225 All data for this period
  3. 2009 days 097-098 or moda 0407-0408 All data for this period
  4. 2009 days 111-112 or moda 0421-0422 All data for this period
  5. 2009 days 173-174 or moda 0622-0623 All data for this period
  6. 2009 days 195-198 or moda 0714-0717 All data for this period
  7. 2009 days 205-205 or moda 0724-0724 All data for this period
  8. 2009 days 214-215 or moda 0802-0803 All data for this period
  9. 2009 days 232-235 or moda 0820-0823 All data for this period
  10. 2009 days 271-272 or moda 0928-0929 All data for this period
  11. 2009 days 289-290 or moda 1016-1017 All data for this period
  12. 2009 days 308-311 or moda 1104-1107 All data for this period
  13. 2009 days 323-323 or moda 1119-1119 All data for this period
  14. 2009 days 362-363 or moda 1228-1229 All data for this period

2010 New.jpg

  1. 2010 days 011-013 or Jan 11-13 All data for this period
  2. 2010 days 032-033 or Feb 01-02 All data for this period
  3. 2010 days 054-055 or Feb 23-24 All data for this period
  4. 2010 days 058-058 or Feb 27 All data for this period
  5. 2010 days 063-063 or Mar 04 All data for this period
  6. 2010 days 075-076 or Mar 16-17 All data for this period

-Revised 26 Jan 2010 by Barbara Emery