Mesospheric Gravity Wave Climatology and Variances over the Andes Mountains

Look up! Travelling over your head in the air are waves. They are present all the time in the atmosphere all over the Earth. Now imagine throwing a small rock in a pond and watching the ripples spread out around it. The same thing happens in the atmosphere except the rock is a thunderstorm, the wind blowing over a mountain, or another disturbance. As the wave (known as a gravity wave) travels upwards the thinning air allows the wave to grow larger and larger. Eventually the gravity wave gets too large – and like waves on the beach – it crashes causing whitewater or turbulence. If you are in the shallow water when the ocean wave crashes or breaks, you would feel the energy and momentum from the wave as it pushes or even knocks you over. In the atmosphere, when waves break they transfer their energy and momentum to the background wind changing its speed and even direction. This affects the circulation of the atmosphere. These atmospheric waves are not generally visible to the naked eye but by using special instruments we can observe their effects on the wind, temperature, density, and pressure of the atmosphere. This dissertation discusses the use of a specialized camera to study gravity waves as they travel through layers of the atmosphere 50 miles above the Andes Mountains and change the temperature. First, we introduce the layers of the atmosphere, the techniques used for observing these waves, and the mathematical theory and properties of these gravity waves. We then discuss the camera, its properties, and its unique feature of acquiring temperatures in the middle layer of the atmosphere. We introduce the observatory high in the Andes Mountains and why it was selected. We will look at the nightly fluctuations (or willy-nillyness) and long-term trends from August 2009 until December 2017. We compare measurements from the camera with similar measurements obtained from a satellite taken at the same altitude and measurements from the same camera when it was used at a different location, over Hawaii. Next, we measure the amount of change in the temperature and compare it to a nearby location on the other side of the Andes Mountains. Finally, we look for a specific type of gravity wave caused by wind blowing over the mountains called a mountain wave and perform statistics of those observed events over a period of six years. By understanding the changes in atmospheric properties caused by gravity waves we can learn more about their possible sources. By knowing their sources, we can better understand how much energy is being transported in the atmosphere, which in turn helps with better weather and climate models. Even now –all of this is going on over your head

Investigating Mesospheric Gravity Wave Dynamics and Temperature Variability over the Andes

Observations of mesospheric OH(6,2) temperatures by the Utah State University Mesospheric Temperature Mapper located at Cerro Pachon, Chile (30.3°S, 70.7°S) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. Comparative studies with other data sets including the satellite-borne SABER instrument show good agreement on nightly, as well as seasonal, temperature measurements

New measurements of McMurdo gravity wave parameters

The ANtarctic Gravity Wave Instrument Network (ANGWIN) is an NSF sponsored international program designed to develop and utilize a network of gravity wave observatories using existing and new instrumentation operated at several established research stations around the continent. The primary goal is to better understand and quantify large-scale gravity wave climatology and their effects on the upper atmosphere over Antarctica. ANGWIN currently comprises research measurements from five nations (U.S., U.K., Australia, Japan, and Brazil) at seven international stations. Utah State University’s Atmospheric Imaging Lab operates all-sky infrared and CCD imagers and an Advanced Mesospheric Temperature Mapper (AMTM) imager at several research stations (Davis, Halley, Rothera, McMurdo, and South Pole). We present new measurements of short-period mesospheric gravity waves imaged from McMurdo Station (77°S, 166°E) on Ross Island. This camera has operated alongside the University of Colorado Fe Lidar during the 2012 winter season (March-September 2012). Image data were recorded every ~10 seconds enabling detailed measurements of individual gravity wave events in the infrared OH emission layer (~87 km). Here we present example wave data and novel measurements of the wave characteristics observed during this winter season

Mesospheric Temperature Variability and Seasonal Characteristics Over the Andes

The Utah State University CEDAR Mesospheric Temperature Mapper (MTM) is a high-quality CCD imager capable of remote sensing faint optical emissions from the night sky to determine mesospheric temperature and its variability at an altitude of ~87 km. The MTM was operated at the new Andes Lidar Observatory (ALO)located at Cerro Pachon, Chile (30.2° S, 70.7° W) since August 2009 to investigate the seasonal characteristic of the mesopause at mid-latitudes. Measurement were made alongside a powerful lidar capable of height sounding the mesosphere. In this study, the MTM data have been analyzed to determine night to night variability and seasonal characteristics in the OH mesospheric intensity and temperature induced by acoustic-gravity waves and atmospheric tides

The First Ten Months of Investigation of Gravity Waves and Temperature Variability Over the Andes

The Andes region is an excellent natural laboratory for investigating gravity wave influences on the Upper Mesospheric and Lower Thermospheric (MLT) dynamics. The instrument suite that comprised the very successful Maui-MALT program was recently re-located to a new Andes Lidar Observatory (ALO) located at Cerro Pachon, Chile to obtain in-depth seasonal measurements of MLT dynamics over the Andes mountains. As part of the instrument set the Utah State University CEDAR Mesospheric Temperature Mapper (MTM) has operated continuously since August 2009 measuring the near infrared OH(6,2) band and the O2(0,1) Atmospheric band intensity and temperature perturbations. This poster focuses on an analysis of nightly OH temperatures and the observed variability, as well as selected gravity wave events illustrating the high wave activity and its diversity

Observations of mesospheric gravity waves over the Andes

Focusing on data from an imager and the SABER instrument aboard the TIMED satellite temperature variances are determined to quantify small-scale gravity waves. IDL software was used to extract all the temperature profile measurements that were measured by SABER within a limited geographical area, centered on our ground-based optical imager at Cerro Pachon, Chile (30.3°S, 70.7°S). Large-scale tidal waves, with wavenumbers 0-6, were removed from each profile revealing the gravity wave perturbations. Temperature variances reveal possible increased wave activity due to mountain waves. Mountain waves in the mesosphere are a relatively unexplored field in aeronomy. They are generated predominantly in winter months by strong winds blowing over mountains creating stationary waves. They propagate upwards growing in amplitude, and deposit momentum and energy in the upper-atmosphere. Initial results will be shown comparing satellite and ground-based observations. This technique has high potential for investigating gravity wave effects with other ground-based measurements around the world

Observations of Mesospheric Temperature Variability Over the Andes

Observations of mesospheric OH(6,2) rotational temperatures by the Utah State University Mesospheric Temperature Mapper (MTM) located at the Andes Lidar Observatory, Cerro Pachon, Chile (30.3°S, 70.7°S) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. This study investigates MTM temperature variability over the past 3.5 years comprising over 800 nights of high-quality data and compares the results with ground-based spectrometric measurements from nearby El Leoncito Observatory, Argentina, Maui-MALT, Hawaii MTM measurements (2001-2005) and coincident mesospheric temperature measurement by SABER on the NASA TIMED satellite

Satellite and Ground-Based Measurements of Mesospheric Temperature Variability Over Cerro Pachon, Chile (30.3° S)

— Observations of mesospheric OH (6,2) rotational temperatures by the Utah State University Mesospheric Temperature Mapper (MTM) located at the Andes Lidar Observatory, Cerro Pachon, Chile (30.3◦ S, 70.7◦ W) reveal a large range of nightly variations induced by atmospheric gravity waves and tides, as well as strong seasonal oscillations. This study investigates MTM temperature variability over the past 4 years comprising over 800 nights of high-quality data and compares the results with MTM measurements from Maui, Hawaii (2001-2005) and coincident mesospheric temperature measurement by the SABER instrument on the NASA TIMED satellite

Investigating Mesospheric Gravity Wave Dynamics Over McMurdo Station, Antarctica (77° S)

The ANtarctic Gravity Wave Instrument Network (ANGWIN) is an NSF sponsored international program designed to develop and utilize a network of gravity wave observatories using existing and new instrumentation operated at several established research stations around the continent. The primary goal is to better understand and quantify large-scale gravity wave climatology and their effects on the upper atmosphere over Antarctica. ANGWIN currently comprises research measurements from five nations (U.S., U.K., Australia, Japan, and Brazil) at seven international stations. Utah State University’s Atmospheric Imaging Lab operates an all-sky CCD, all-sky infrared imagers and an Advanced Mesospheric Temperature Mapper (AMTM) imager at several research stations (Davis, Halley, Rothera, McMurdo, and South Pole). In this poster we present new measurements, mainly focusing on short-period (\u3c 1 hour) mesospheric gravity waves, imaged from McMurdo Station (77°S, 166°E) on Ross Island, Antarctica. The infrared camera has operated successfully from the NSF Arrival Heights Facility alongside the University of Colorado Fe Lidar during the past three winter seasons (March-September 2012-2014). Image data were recorded every ~10 seconds enabling detailed measurements of individual gravity wave events in the infrared OH emission layer (peak altitude ~87 km). Here we present example data illustrating the broad range of wave activity observed at this site and summarize novel measurements of the wave characteristics observed during the first two winter seasons. The results are contrasted with other emerging ANGWIN wave measurements from around the continent