| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | April 26, 2012 |
| Latest Amendment Date: | July 2, 2014 |
| Award Number: | 1138938 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Anne-Marie Schmoltner
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | May 1, 2012 |
| End Date: | April 30, 2016 (Estimated) |
| Total Intended Award Amount: | $173,666.00 |
| Total Awarded Amount to Date: | $173,666.00 |
| Funds Obligated to Date: |
FY 2013 = $57,608.00 FY 2014 = $59,392.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1109 GEDDES AVE STE 3300 ANN ARBOR MI US 48109-1015 (734)763-6438 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1416 Space Research Building Ann Arbor MI US 48109-2143 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | AERONOMY |
| Primary Program Source: |
01001314DB NSF RESEARCH & RELATED ACTIVIT 01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
This is a 3-year experimental project to be undertaken as part of the Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR) program. The main objective is to install and operate a small network of Fabry-Perot interferometers (FPI) in the central eastern United States. The network will consist of four stations with a site-to-site separation between 350 and 700 km allowing common volume measurements of winds and temperatures in the thermosphere that together provide a regional view of the thermospheric wind structure and dynamics. This includes quantifying the latitudinal and longitudinal extents, propagation direction, and speed of wave events, source regions, and other dynamical quantities that are not possible with current available instrument deployments. Supporting data from available ground-based magnetometers and radars as well as space-based measurements of magnetic fields, ion drifts and auroral precipitation will be used together with a global thermosphere/ionosphere general circulation model to provide a global context for the measurements. In this way, the observations will facilitate breakthrough insights about the dynamics of the thermosphere including the propagation of large-scale disturbances away from the auroral zone and the response of the mid-latitude thermosphere to geomagnetic disturbances. Strategies and algorithms will be developed as part of this project to change the observing strategy in real-time based, for example, upon the local cloud conditions.
The operational experience gained from this network will serve as a proof of concept for a much larger-scale network required for a more complete investigation of thermospheric dynamics. The pilot network will make technological advances in regard to issues such as understanding how to operate the chain as a unit, how to consistently process data in real time, and how to visualize and interpret results from multiple stations. The project is a collaboration between a team of professors at Clemson University, the University of Michigan, and University of Illinois. Deployment and operation of the instruments and the network will provide hands on training opportunities for graduate and undergraduate students at each of the universities.
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The thermosphere is the highest region of the atmosphere. It is called the thermosphere because it absorbs significant amounts of energy from the sun - namely in the Ultraviolet, Extreme-Ultraviolet, and X-ray wavelengths. This makes the thermosphere significantly hotter than any other region of the atmosphere. In addition to the sun's energy, the aurora is absorbed in the thermosphere. Because the aurora changes quite dramatically over time, it can strongly change the way the upper atmosphere behaves. The majority of the time, the aurora only adds a little bit of energy to the atmosphere, but some times, there are large geomagnetic storms, and the amount of energy going into the atmosphere in the region of the aurora can increase by a couple of orders of magnitude. When this happens, the thermosphere becomes significantly hotter, and the winds patterns change dramatically.
This project specifically focused on exploring how those wind patterns are controlled by the auroral input, and how they can change over time. We set up a series of instruments to measure the winds in the thermosphere. The instruments remotely sensed the wind by using two different ideas: (1) the upper atmosphere glows - it looks a bit read and a bit green; and (2) the wavelength of light that is measured by something is dependent on the velocity of the object that is emitting the light.
Atoms in the atmosphere can become excited through chemistry or absorbing sunlight or other means. When the light becomes de-excited, it ends up giving off light of a certain color. In the thermosphere, the Oxygen primarily emits green and red light of two very specific wavelengths: 557.7 nm and 630.0 nm, respectively. The green light is emitted at about 100 km altitude, while the red light is emitted at about 250 km altitude.
Doppler shift is when a receiver, like an instrument or a person, sees or hears a shift in wavelength or frequency of light or sound, due to the relative motion between the thing that is emitting the light or sound and the receiver. A simple example is when a train passes you and its horn goes from a high pitch when it is moving towards you to a lower pitch when it is moving away. If you had an incredibly sensitive instrument, you could also see the headlight change a small amount in color when it passed also. The reason that the horn pitch changes so much is because for sound the pitch change with respect to the speed of sound, while with light, the wavelength changes with respect to the speed of light, which is extremely fast. So, things have to be moving VERY fast in order for humans to perceive any change in color. But, with a very sensitive instrument, these changes can be easily observed.
We deployed five Fabry Perot Interferometers that simply looked up at the sky with a very narrow field of view (like with binoculars). These instruments can measure the super tiny Doppler shifts made by the atoms that are moving and emitting light in the thermosphere. With five of them, we can measure the wind from the near the auroral zone to the near the equatorial region. When the aurora increases dramatically, like during a geomagnetic storm, we can measure how the winds change over this region.
The goal of this project was to set up the instruments and measure the winds during some of these events to explore the weather in the thermosphere.
Last Modified: 08/05/2016
Modified by: Aaron J Ridley
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