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The Utah State University (USU) campus (41.7°N, 111.8°W) hosts a unique upper atmospheric observatory that houses both a high-power, large-aperture Rayleigh lidar and a Na lidar. For the first time, we will present 19 nights of coordinated temperature measurements from the two lidars, overlapping in the 80–110 km observational range, over one annual cycle (summer 2014 to summer 2015). This overlap has been achieved through upgrades to the existing USU Rayleigh lidar that increased its observational altitude from 45–95 to 70–115 km and by relocating the Colorado State Na lidar to the USU campus. Previous climatological comparisons between Rayleigh and Na lidar temperatures have suggested that significant temperature differences exist between the two techniques. This new comparison aims to further these previous studies by using simultaneous, common-volume observations. The present comparison showed the best agreement between 85 and 95 km, with a temperature difference, averaged over the whole data set, of about 1.1 ± 0.5 K. Larger differences occurred above and below these altitudes with the Rayleigh temperatures being colder by about 3.5 ± 0.5 K at 82 km and warmer by up to 9.1 ± 3.5 K above 95 km.

Temperatures from a collocated Rayleigh-scatter lidar (RSL) and sodium resonance lidar were compared night-by-night, at different altitude levels, and hour-by-hour. Three zipped files are provided. USU RSL 2014-2015 [O] Corrected Temperatures.zip contains 36 files, one per night and hour, in RSLHourlyTemperaturesYYYYMMDDhour#.txt filename format. USU RSL 2014-2015 Hourly Temperatures.zip contains 36 files, one per night and hour, in RSLHourlyTemperaturesYYYYMMDDhour#.txt filename format. USU RSL 2014-2015 Nightly Temperatures.zip contains 19 files, one per night, in RSLTemperaturesYYYYMMDD.txt filename format.

There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh-scatter (RS) and resonance lidars, particularly sodium (Na) resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics and long-term temperature trends of the MLT region can be studied. For the first time, we will present simultaneous, night-time averaged temperatures acquired from the same observational site, on the campus of Utah State University (USU), using these two lidar techniques. This comparison is also unique in that this will be the first time that the Rayleigh and Na lidar profiles will cover the same altitude range (80-110 km). This altitude overlap has been achieved through upgrades to the existing USU Rayleigh lidar, which elevated its observational range from 45-90 km to 70-115 km, making it one of two Rayleigh lidars in the world that can extend into the thermosphere, and by the relocation of the Colorado State Na lidar to the USU campus. The comparison of the two sets of temperature measurements is important because the two lidar techniques derive temperature profiles using different observational techniques and analysis methods, each of which are based on different sets of physical assumptions and theories. Furthermore, previous climatological comparisons between Rayleigh and Na lidar, in the 80-90 km range, have suggested that significant temperature differences can occur. This comparison aims to extend the climatological studies by exploring the agreement between the lidar techniques’ temperatures with respect to altitude and season.

The Rayleigh-scatter lidar at the Atmospheric Lidar Observatory at Utah State University (ALO-USU; 41.74° N, 111.81° W) started observations in 1993. In 2012 the original lidar system was upgraded with an array of larger mirrors and two lasers to enable observations of the upper mesosphere and lower thermosphere from 70 km to about 115 km in altitude. (Continued refinement should provide data to above 120 km.) Recently, the original system was reconfigured [Elliott et al., 2016] to again observe the lower mesosphere between 40 km and 90 km. Initial data collected by these two parts of the Rayleigh system have been “stitched” together to obtain a full temperature profile from 40 km to about 115 km. These extended profiles have been used to obtain relative neutral densities and temperatures through the entire mesosphere and well into the lower thermosphere. This extends the CEDAR goal of studying coupling between atmospheric regions. Furthermore, by normalizing the relative neutral densities between ~35 and 45 km to an advanced reanalysis model, absolute neutral densities become available from a ground-based, remote-sensing instrument all the way into the lower thermosphere. This opens that region to detailed studies for many research topics.

The Earth���s middle atmosphere is comprised of the stratosphere, mesosphere and thermosphere, from approximately 10 to 110 km, or approximately 6 to 68 miles. An understanding of the dynamics and climatological conditions in this region is of vital importance to the aerospace industry and military, which both launch aircraft and spacecraft into this region, as well as researchers who study climate change and the interactions between the atmosphere and the Earth, oceans, and space. Measurements of atmospheric properties (density, temperature, and pressure) in this region are relatively difficult to gather as the middle atmosphere���s altitudes are both too high for weather balloons to reach and too low for satellite. That is why most instruments that acquire data from the middle atmosphere are of the remote sensing variety. Rayleigh-scatter lidar (light detection and ranging) is a remote sensing technique that is particularly effective at acquiring long-term measurements of the middle atmosphere. This work focuses on the design and implementation, over one annual cycle, of a unique Rayleigh lidar, which pushes the upper altitude boundary that is typical of such systems. In addition, a study of the connection between Sudden Stratospheric Warmings and the midlatitude mesosphere using a long-term Rayleigh lidar dataset is presented.

There are relatively few instruments that have the capabilities to make near continuous measurements of the mesosphere-lower-thermosphere (MLT) region. Rayleigh scatter and resonance lidars, particularly sodium resonance lidar, have been the two dominant ground-based techniques for acquiring mesosphere and MLT vertical temperature profiles, respectively, for more than two decades. With these measurements, the dynamics (gravity waves, tides) and long-term temperature trends (upper atmosphere cooling) of the MLT region can be studied. The Utah State University (USU; 41.7º N, 111.8º W) campus hosts a unique upper atmospheric observatory which houses both a high-power, large-aperture Rayleigh lidar and a sodium resonance Doppler lidar. For the first time, we will present coordinated, night-time averaged temperatures, overlapping in observational range (80-110 km), from the two lidars. This overlap has been achieved through the relocation of the sodium lidar from Colorado State University to USU’s campus and through upgrades to the existing USU Rayleigh lidar which elevated its observational range from 45-90 km to 70-115 km. The comparison of the two sets of temperature measurements is important because the two lidar techniques derive temperature profiles using different scattering processes and analysis methods. Furthermore, previous climatological comparisons, between Rayleigh and sodium lidar, [Argall and Sica, 2007] have suggested that significant temperature differences can occur. This comparison aims to explore possible temperature effects from the differences in the two measurement techniques.

Rayleigh-scatter lidar observations were made on many clear nights at the Atmospheric Lidar Observatory (ALO) at Utah State University (USU) from 1993 to 2004 in the altitude range 45–90 km. An upgraded facility, 66 times more sensitive, has been brought on line. It has resulted in temperature measurements with maximum altitudes that extend into new territory—the lower thermosphere. All-night temperature averages have been recorded up to an altitude of 114 km. Temperatures from each month, starting in June 2014, are presented and discussed. They are compared to each other, to the ALO-USU climatology from the original lidar, and to temperatures from the NRLMSISe00 empirical model.

The National Science Foundation sponsors Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) Workshops, which have been held every summer, for the past 27 years. CEDAR Workshops are on the order of a week long and at various locations that are close to university campuses where CEDAR type scientific research is done. Although there is no formal student group within the CEDAR community, the workshops are very student-focused. Roughly half the Workshop participants are students. There are two Student Representatives on the CEDAR Science Steering Committee (CSSC), the group of scientists who organize the CEDAR Workshops. Each Student Representative is nominated by his or her peers, chosen by the CSSC and then serves a two year term. Each year, one of the Student Representatives is responsible for organizing and moderating a day-long session especially for students, made up of tutorial talks, which aim to prepare both undergraduate and graduate students for the topics that will be discussed in the main CEDAR Workshop. The theme of this session changes every year. Past themes have included: upper atmospheric instrumentation, numerical modeling, atmospheric waves and tides, magnetosphere-ionosphere coupling, equatorial aeronomy and many others. Most every Student Workshop has ended with a panel of post-docs, researchers and professors who discuss pressing questions from the students about the next steps they will take in their careers. As the present and past CSSC Student Representatives, we will recount a brief history of the CEDAR Workshops, our experiences serving on the CSSC and organizing the Student Workshop, a summary of the feedback we collected about the Student Workshops and what it’s like to be student in the CEDAR community.

A Rayleigh-scatter lidar operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W), part of Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected extensive data between 1993 and 2004. From the Rayleigh lidar photon-count profiles, relative densities were determined throughout the mesosphere, from 45 to 90 km. Using these relative densities three climatologies were derived, each using a different density normalization at 45 km. The first normalized the relative densities to a constant; the second to the NRL-MSISe00 empirical model which has a strong annual component; and the third to the CPC analyses model, which is similar to MSIS in that it has a strong annual oscillation. In each case the density profile for every night of a composite year was found by averaging the nighttime density profiles over a 31-day by 11-year window centered on that day. For each of the cases, the average annual density profile was found by averaging all the days. Then the daily percent differences were found relative to the annual density profile. Despite the different normalizations at 45 km, many common features were found in the seasonal behavior of the density profiles, a large seasonal variation maximizing in June at ~70 km, Another above 80 km is a large shift in the maximum to earlier in the year, and lastly sharp density fall off at almost all altitudes in early October. While these density normalizations provide initial information about mesospheric behavior, the current lidar upgrade will enable us to add an absolute scale to the density profiles.

While the mesospheric temperature anomalies associated with Sudden Stratospheric Warmings (SSWs) have been observed extensively in the polar regions, observations of these anomalies at midlatitudes are sparse. The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected a very dense set of temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. This work focuses on the extensive Rayleigh lidar observations made during seven major SSW events that occurred between 1993 and 2004, and aims to compile a climatological study of the midlatitude mesospheric temperatures during these SSW events. In order to determine the characteristics of the midlatitude mesospheric temperatures during SSWs, comparisons were made between the temperature profile on an individual night during a SSW event and the climatological (11-year average) temperature profile for that night. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings in the upper mesosphere, comparable to those seen in the polar regions, and warmings in the lower mesosphere.

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.

The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU) collected a very dense set of temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. This work will focus on the extensive Rayleigh lidar observations made during the seven major SSW events that occurred between 1993 and 2004. In order to determine the characteristics of the midlatitude mesospheric temperatures during SSWs, comparisons were made between the temperature profile on an individual night during a SSW event and the climatological (11-year average) temperature profile for that night. An overall disturbance pattern was observed in the mesospheric temperatures during these SSWs. It included coolings (sometimes very significant) in the upper mesosphere and warmings in the lower mesosphere.

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. The lidar consisted of a 0.44-m diameter mirror, a frequency-doubled Nd:YAG laser opera'ng at 532-nm at 30- Hz at either 18- or 24-W, giving power- aperture products (PAPs) of 2.7- or 3.6- Wm2, respec'vely, and one detector channel. An example of what was accomplished with this system is shown as part of Fig. 1. The temperature climatology was based on ~5000 hours of observa'ons carried out over ~900 nights. The temperatures, with 3-km al'tude resolu'on, were averaged over periods of 31 days by 11 years. The ALO Rayleigh lidar is currently being upgraded, as indicated, as indicated in Fig. 1, to extend observations upward into the lower thermosphere and downward to the lower stratosphere.

Rayleigh lidar systems have historically made ground-based observations of the upper atmosphere (stratosphere and mesosphere) from 35-90 km. This technology has helped fill the data collection gap between the troposphere and space. Recently our Rayleigh lidar group at the Atmospheric Lidar Observatory on the campus of Utah State University (42° N, 112° W) upgraded the original lidar system in order to extend the measurement range for neutral densities and temperatures to higher altitudes and has increased the upper limit, so far, from 90 to 110 km. Next, we will extend the lower altitude limit downward to 15 km. This will enable us to connect densities, temperatures, and their fluctuations in the mesosphere and lower thermosphere to the drivers in the lower portions of the atmosphere. Extending measurements downward will lead to signals, not only from Rayleigh scatter off of small particles (N2 and O2), but also from Mie scatter off of much larger particles (aerosols). In order to separate the Rayleigh and Mie signals we will take advantage of the system’s greater sensitivity to measure Raman scatter from N2, between 15 and 35 km, thus making the system a Rayleigh-Mie-Raman (RMR) lidar. We can then apply the Klett Inversion algorithm to separate these signals in the data reduction. Such an extended altitude range will enable us to make observations of atmospheric processes and phenomena, such as disturbances, waves and sudden stratospheric warmings, which can ripple up from the ground throughout the atmosphere. This range will also enable an absolute calibration of densities with data from radiosondes and assimilative models like NCEP. The absolute calibration of atmospheric densities can provide a starting point for neutral models of the thermosphere, which are often used to predict satellite drag. In addition, the RMR lidar extended altitude range will provide significant overlap with satellite remote sensing measurements, which will help with calibration and validation efforts and in the extension of satellite measurements towards the ground. The RMR lidar will provide complementary measurements to those made by satellites by providing data that can measure the time evolution of atmospheric processes in one location, while satellite instrumentation gives global measurements of atmospheric processes. This talk will focus on a description of the system and the latest results as well as a discussion of the full upgrade design and how it impacts NASA efforts.

The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. Recently, these temperatures were combined with other observations to examine the mid-latitude response to Sudden Stratospheric Warmings (SSWs) in the polar regions. Extensive Rayleigh lidar observations were made during a several SSW events. In order to look for effects of the SSWs, comparisons were made between the temperature profile on individual nights during an SSW event and the climatological temperature profile for that night of the year. An overall disturbance pattern was observed in the mesospheric temperatures during northern hemisphere SSWs. It included coolings (sometimes very significant) in the upper mesosphere and warmings in the lower mesosphere, which were often related to increases in the stratopause altitude. Currently, the ALO Rayleigh lidar system is going through a series of upgrades to transform it to a Rayleigh-Mie-Raman (RMR) scatter lidar. The scientific impetus for these upgrades is to extend the observing range both higher and lower in altitude. This will be achieved by increasing the sensitivity by 70 times, which will make this the most sensitive lidar, of its type, in the world. This will allow measurements to be made of relative densities and absolute temperatures throughout most of the stratosphere, mesosphere and lower thermosphere, from approximately 15 to 120 km. After the upgrade, the intent, as with the original Rayleigh lidar, is to observe as often as possible. This will provide an extensive data set for many types of analyses. Initially, it will provide good information about the poorly observed region between 90 and 120 km. Later, by normalizing the relative lidar densities to absolute densities in a reanalysis model or to observed radiosonde densities below 30 km, an absolute density profile will be obtained for the first time up to 120 km. There are many scientific applications that will benefit from the extended range of the new RMR lidar. For instance, new observations could extend the description of SSW occurrences from the stratosphere and mesosphere into the lower thermosphere, observed thermospheric densities could be provided for the models used to evaluate satellite drag, especially during major space weather events, and the effects of weather events in the lower atmosphere could be traced all the way to the thermosphere. Already, we have found significant temperature differences between observed temperatures and those from the MSISe00 empirical model.

The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected temperature data for 11 years, from 1993 through 2004. The temperatures derived from these data extended over the mesosphere, from 45 to 90 km. Recently, they were combined with other observations to examine the mid-latitude responses to Sudden Stratospheric Warmings (SSWs) in the polar regions. (The other observational instruments being an ionosonde, a meteor wind radar, a Na lidar, and a satellite.) Extensive Rayleigh lidar observations were made during a dozen SSW events. In order to look for effects of the SSWs, comparisons were made between the temperature profile on individual nights during an SSW event and the climatological temperature profile for that night of the year. An overall disturbance pattern was observed in the mesospheric temperatures during northern hemisphere SSWs. It included coolings (sometimes very significant) in the upper mesosphere and warmings in the lower mesosphere. Examples of the effects in the mesosphere from southern hemisphere SSWs are also given.

The original Rayleigh-scatter lidar that operated at the Atmospheric Lidar Observatory (ALO; 41.7°N, 111.8°W) in the Center for Atmospheric and Space Sciences (CASS) on the campus of Utah State University (USU), collected 11 years of data between 1993 and 2004. From Rayleigh lidar photon-count returns, relative densities throughout the mesosphere, from 45 to 90 km, were determined. Using these relative densities, three climatologies are derived, each using a different density normalization method at 45 km: the first method normalized the relative densities to a constant; the second normalized them to the NRLMSISe00 empirical model; and the third normalized them to the CPC analyses, a first principles, assimilative, meteorological model. From there, the average density profile for each night of the composite year is found by averaging the nighttime density profiles in a multi-year, 31-day window centered on that particular night. From these three density climatologies, some different and many common features in the mesospheric densities are evident. In the future, with improvements to the lidar, it will be possible to provide an absolute normalization for the density profiles.

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 waves (gravity waves, tides, planetary waves), while climatological studies of temperatures can help in the study of global change throughout the atmosphere.

In June–July 2012, observations were carried out using the recently upgraded, large-aperture, Rayleigh-scatter lidar system located at the Atmospheric Lidar Observatory (ALO) on the campus of Utah State University, in Logan, UT (41.7 N, 111.8 W). This time period was significant because it enabled us to observe the annual temperature minimum in the upper mesosphere-lower thermosphere region. The data collected during the campaign were analyzed for temperatures between ~70–109 km. The results above ~95 km are the first obtained with a Rayleigh-scatter lidar, extending the technique well into the lower thermosphere. A great deal of variability from night-to-night is evident in these temperature profiles and in the mesopause altitude. The profiles also show considerable wave activity from large amplitude waves. The temperatures are compared to those from the MSISe90 model and from the 11-year ALO temperature climatology. This new capability for the ALO Rayleigh lidar, like any new observational capability, opens the potential for new discoveries in this hard-to- observe region.

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 campaign show a considerable night to night variation as well as evidence of wave activity on several nights.

The Rayleigh-Scatter lidar system at the Atmospheric Lidar Observatory (ALO) on the Utah State campus is currently going through a series of upgrades to significantly improve its observational abilities. A specific objective of these upgrades is to expand the altitude range over which backscattered photons can be collected. A second objective is to increase the sensitivity of the instrument to be able to analyze the raw data at finer temporal and/or spatial resolutions. By measuring relative densities, the system will be able to produce absolute temperatures and relative density perturbations, which illustrate gravity wave structures. Gravity wave studies will significantly benefit from the improved system due to the waves’ propagation throughout the atmosphere and their evolving structures on various spatial and temporal scales during propagation. Preliminary data will be shown and its relevance to further gravity wave studies will be explained.

Rayleigh-Scatter lidar systems effectively use remote sensing techniques to continuously measure atmospheric regions, such as the mesosphere (45-100km) where in situ measurements are rarely possible. The Rayleigh lidar located at the Atmospheric Lidar Observatory (ALO) on the Utah State campus is currently undergoing upgrades to make it the most sensitive of its kind. Here, the important components of these upgrades and how they will effect the study of a particular atmospheric phenomena, atmospheric gravity waves, will be discussed. We will also summarize what has been done to the system during this year to bring us to the threshold of initial operations.

The mesosphere is the most unexplored region of the atmosphere. Its altitude range of 50-85 km lies in between the reaches of data collecting instruments like weather balloons and satellites. For this reason, remote sensing systems, such as lidar, which are able to employ ground-based instruments to make extensive measurements in this difficult to detect region. The Rayleigh-scatter lidar at USU is currently being redeveloped to be the most powerful and sensitive of its kind. This type of lidar exploits light and particle interactions, like those that account for the blue color of the sky, to make relative density and absolute temperature measurements. In turn, the variation in these densities and temperatures can be analyzed to further explore atmospheric phenomena that are either the cause of or caused by these variations. By increasing the power output and measurement sensitivity, this lidar system will be unique in its expansive altitude range and in its capabilities of measuring small spatial and time scale atmospheric phenomena. Atmospheric gravity waves are one form of such phenomena that will be studied, as they are an important component of atmospheric dynamics.

We have observed pollen in the local troposphere using the depolarization capabilities of a LIDAR (Light Detection and Ranging) system. The polarization characteristics of the received LIDAR signal, along with supplemental pollen forecast data, allowed me to characterize the shape of the pollen particles.