1. Dataset Title: USU Na Lidar Data
2. Name and contact information of PI:
a. Name Titus Yuan
b. Institution Utah State University
c. Address Utah State University, SER Blog 318 D; Logan UT 84322
d. Email titus.yuan@usu.edu
e. ORCiD ID https://orcid.org/0000-0003-3008-0171


6. National Science Foundation, AGS 1135882 and AGS 1734333 (Agency, Grant Number) if applicable

7. Project summary, description or abstract: The naturally exist mesospheric Na layer, overlapping upper mesosphere and lower thermosphere, provides an excellent tracer for lidar remote sensing. The Na Doppler lidar technique is designed to measure neutral temperature and wind profiles in the mesopause region (~ 80-110 km) by observing the thermal broadening and Doppler shift of atomic Na fluorescence spectrum. Relocated from Colorado State University (CSU), the Na lidar at Utah State University (USU) has been operating since summer 2010 with operation hour of roughly 1000 hours per year. Enabled by a pair of Faraday filters, it has unique daytime observation capability to study not only small scale dynamics features, but also large scale tidal and planetary wave activities. Combined with the lidar database at CSU, this project has the longest mesopause region temperature database in the world (29 years and counting). This invaluable database has enabled several long-term trend study in the upper atmosphere, which is mostly related to the increasing CO2 diffusion from troposphere into the upper atmosphere and the stratosphere contraction. 

8. Brief description of collection and processing of data: The lidar hardware is set up so that the lidar signals were binned with 150 m in line of sight direction and saved every minute. Different temporal and spatial resolutions can be applied later during data processing, when the temperature and wind information in the upper atmosphere are derived. 

9. Description of files (names, or if too numerous, number of files, file type(s):
The data are in text format with resolution of one-hour. For higher resolution, please contact the PI of the Na lidar. Please also acknowledge the PI, if the lidar data are utilized for any publication or conference presentation.Ê
File name starting with "Tint..." are temperature files and those with ÒVintÉÓ are line-of-sight wind files. Those starting with "DenintÉ" are Na density files. The ÒSummaryÉÓ files provide a brief summary of the lidar data.Ê
In each data file, the first 30 something lines are about the information on the lidar run. The UT time of the lidar operation is line 5. Data start at line where the first word is "altit". In this line, you will see headers, such as "DenNaPhottoNightÉ" (for Na density files) etc. The lines below are the data: The first column is altitude; the second and third columns are nightly averaged temperature or Na density (we process the nightly average in two different ways, they should be quite similar, except near the edge of the Na layer). Starting from the fourth column, you can read the lidar measurement for each hour. Following all the lidar hourly measurements are uncertainties for each hour (Note, we calculate the temperature uncertainty in two different ways, so you will see two sets of temperature uncertainty in the Tint files. However, they are pretty much the same, so you can use either one of them).
The structure for the lidar wind data is the same, except that the lidar was running in different beam configuration from time to time. Thus, to get horizontal wind, the users have to convert the line-of-sight (LOS) wind to horizontal wind themselves based on the angle of the lidar beam pointing with respect to zenith direction by dividing the LOS wind by the sine of the tilting angle. In 2018, the files with extension of Ò_27_Ó are zenith pointing lidar beam, so they provide the vertical wind directly; those with extension of Ò_29_Ó are east pointing beam with off-zenith angle of 20; those with extension of Ò_31_Ó are north pointing beam with off-zenith angle of 30.


12. Descriptions of parameters/variables: The data products include profiles of neutral temperature, winds and Na density between 70 km and 120 km.
a. Temporal (beginning and end dates of data collection) January 2018 - present

d. Location/GIS Coverage (if applicable to data): 41.7?N 111.8?W
e. Symbol used for missing data: 100.00 for temperature and wind (the uncertainty is 999.80); 0.00e+000 for Na density 

4. Related datasets outside of this dataset: The lidar data before 2018 are available at the CRRL Madrigal data base at:Êhttp://madrigal.physics.colostate.edu/htdocs/