Physics Commons^™

Extremely Sensitive Rayleigh-Scatter Lidar At Usu, Vincent B. Wickwar, Leda Sox, David Barton, Matthew T. Emerick

Posters

Rayleigh lidar opened a portion of the atmosphere, from 30 to 90 km, to ground-based observations. Rayleigh-scatter observations were made at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU) from 1993–2004 between 45 and 90 km, creating a very dense data set consisting of ~5000 hours of observations carried out over ~900 nights. The lidar had a mirror of area 0.15 m2 and a frequency-doubled Nd:YAG laser operating at 532 nm at 30 Hz at ~21 W, giving a power-aperture product (PAP) of ~3.1 Wm2.

Rayleigh Lidar Temperature Studies In The Upper Mesosphere And Lower Thermosphere, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Matthew T. Emerick

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Rayleigh lidar technology opened the middle atmosphere (from 30–90 km) to ground-based observations. The upgraded system at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University (41.74, 111.81) has shown that these ground-based observations can be extended to 109 km, with the goal of reaching 120 km. The resultant study of short and long-term temperature trends, using Rayleigh lidar, contributes immensely to the overall understanding of the properties and dominant physical processes in the middle atmosphere and Mesosphere-Lower Thermosphere (MLT) region. Temperature variations on short time scales, from minutes to days, give insight into the effects of …

First Temperature Observations With The Usu Very Large Rayleigh Lidar: An Examination Of Mesopause Temperatures, Leda Sox, Vincent B. Wickwar, Joshua P. Herron, Marcus J. Bingham, Lance W. Petersen, Matthew T. Emerick

Posters

As the impetus for extended observational measurements throughout the middle atmosphere has increased1 , the limits of previous instrumentation need to be pushed. The Rayleigh lidar group at the Atmospheric Lidar Observatory (ALO) at Utah State University has pushed such limits on existing Rayleigh scatter lidar technology and, through major upgrades to the previous lidar system, has been able to gather temperature measurements in the upper mesosphere and lower thermosphere from approximately 70P109 km. A data campaign with the new system was conducted around the annual temperature minimum, centered on late June 2012, in this region. The temperatures from this …

Early Observations Of The Middle Atmosphere Above Usu With The World’S Most Sensitive Lidar, Lance W. Petersen, Marcus J. Bingham, Vincent B. Wickwar, Joshua P. Herron

Posters

Extensive measurements have been made of the upper atmosphere by satellites and the lower atmosphere is measured twice daily by weather balloons. In contrast, the middle atmosphere is a difficult area to measure and therefore has been much less extensively studied. We are currently upgrading an old lidar system to a new system that will be 70 times more sensitive, making this the most sensitive lidar of its kind in the world. The upgrade consists of combining the outputs of 18 and 24 watt Nd:YAG lasers; implementing an optical chain to detect backscattered light using an existing large, four-mirror telescope; …

Rayleigh-Lidar Observations Of Mesospheric Instabilities, Gabriel C. Taylor, Durga N. Kafle, Vincent B. Wickwar

Posters

From 1993 to 2004 the Utah State University Rayleigh lidar, known as the USU green laser, collected 900 nights of data from the mesosphere (45-90 km). From these observations profiles of relative neutral densities and absolute temperatures were derived. Usually, the atmosphere is horizontally stratified with a balance between gravitational and pressure forces. When this balance is perturbed, it leads to the generation of buoyancy or “gravity” waves. An example of these is clear air turbulence, which can have dramatic effects on airplanes. As these waves propagate upward, the decrease in atmospheric density and conservation of energy combine to give …

Comparisons Of Long-Term Trends And Variability In The Middle Atmosphere, Troy Wynn, Joshua P. Herron, Vincent B. Wickwar

Posters

The USU Rayleigh Lidar (41.74°N 111.81°W) has been regularly used to measure temperatures in the middle atmosphere from 45 to 90 km. It is well suited for nightly observation; provides excellent vertical temperature resolution; and does not need external calibration. It began operation in August 1993 and a dataset spanning more than ten years has been collected. The analysis here includes 593 nightly temperature profiles from September 1993 through July 2003.

With many sources of variation in the atmosphere, all temperature effects cannot be easily detected. The largest source of temperature variation, and the easiest to measure, is the annual …

Rayleigh-Lidar Observations Of Mesospheric Mid-Latitude Density Climatology Above Utah State University, Eric M. Lundell, Vincent B. Wickwar

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Data from Rayleigh lidars have been used extensively to derive temperatures in the mesospheric region of the atmosphere. However, these data have not been used extensively in a similar way to derive neutral densities. We report on one such mid-latitude, density climatology between 45 and ~90 km, based on nearly 600 good nights of observations carried out since 1993 at the Atmospheric Lidar Observatory (ALO) at Utah State University (41.7°N 111.8°W). They produce relative density profiles that are then normalized at 45 km to an empirical model, in this case the MSISe00 model. Despite this normalization, significant differences are found …

Comparisons Of Long-Term Trends And Variability In The Middle Atmosphere, Troy Wynn, Joshua P. Herron, Vincent B. Wickwar

Posters

Rayleigh Lidar is routinely used to measure temperatures in the middle atmosphere from 45 to 90 km. It is well adapted for nightly observation, provides excellent vertical temperature resolution, and does not need external calibration. The USU Rayleigh Lidar (41.74°N 111.81°W) dataset spans more than ten years from September 1993 to July 2003 with 62 monthly profiles (about 5 years of data) spread over that period.

With many sources of variation in the atmosphere, all temperature effects cannot be detected. The largest source, and the easiest to measure, is the seasonal variation. In addition there are semiannual variation, secular trends, …