| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
|
| Initial Amendment Date: | July 29, 2010 |
| Latest Amendment Date: | August 28, 2015 |
| Award Number: | 0925893 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Ilia Roussev
AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | August 1, 2010 |
| End Date: | January 31, 2016 (Estimated) |
| Total Intended Award Amount: | $259,032.00 |
| Total Awarded Amount to Date: | $284,032.00 |
| Funds Obligated to Date: |
FY 2011 = $86,427.00 FY 2012 = $88,566.00 FY 2015 = $25,000.00 |
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
1 SILBER WAY BOSTON MA US 02215-1703 (617)353-4365 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
1 SILBER WAY BOSTON MA US 02215-1703 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): |
AERONOMY, Geospace Sci Cluster Prgrm |
| Primary Program Source: |
01001112DB NSF RESEARCH & RELATED ACTIVIT 01001213DB NSF RESEARCH & RELATED ACTIVIT 01001516DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The goal of this project is to conduct robust scientific analysis of large amounts of incoherent scatter radar (ISR) observations of the terrestrial ionosphere within the framework of a new educational curriculum for undergraduate and graduate students. The ISR data, which have been acquired from multiple facilities over the past several decades, are historically under-utilized, and this project addresses several targeted areas of upper atmospheric research to be pursued by students under the mentorship of the principal investigator. These research topics - assessment of long term trends, response to changes in solar activity, and characterizing the midnight temperature maximum - represent long-standing areas of significant importance to geospace science goals. The project will focus on specific research questions within these areas, which are both well suited for individual student projects as well as scientifically justified based on pilot studies and a thorough consideration of existing literature.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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 award allowed undergraduate and graduate students to recover and analyze decades of incoherent scatter radar data from four different Observatories: Jicamarca, Arecibo, Millstone Hill, and Saint Santin.
One of the topics addressed was related to long-term changes in the thermosphere. It was observed that the thermosphere is cooling at a pace much faster than can be explained by the increase in greenhouse gases. Further, the pace of change accelerated strongly in the mid-to-late 1970s, a 'breakpoint' seen in all atmospheric parameters viewed. The thermospheric cooling nearly ceases at night, again questioning the CO2 hypothesis.
During the award period a new asymptotic theory for the F layer was developed. It predicts well the layer peak height and density and their change with applied wind, all based on simple force-balance relations and not requiring differential equations.
Finally, during the last two years of the award, emphasis was given to the study of the midnight temperature maximum (MTM), an increase in the neutral temperature in the thermosphere occurring near midnight, originally believed to be occurring at ~300 km and near the equator. The MTM was observed to occur at the four radar locations, as high as 40 degrees latitude. A method to automatically extract relevant parameters of the MTM was developed. It consisted in fitting the data with a function constructed as a superposition of harmonic functions and Gaussian fits. From the fitting, the peak value, local time and width of the MTM were extracted. It was observed that during local summer the MTM happens earlier, a result that is supported by satellite observations and model results. One of the great advantages of studying the MTM with radars is that one can obtain an altitude profile of atmospheric parameters. This allowed us to determine that the MTM occurs from ~250 km to ~450 km, showing the large height extent of the increased temperature. We have also shown that the local time of occurrence is earlier at lower latitudes.
Overall, the results provide evidence of the large spatial context of MTM occurrence. During this study we used a capability hardly used with the Millstone Hill Observatory: its low elevation scan mode. This allows the study of ionospheric parameters at latitudes as low as 30 degrees, above the Atlantic Ocean, a valuable tool to sample a region that cannot be accessed by ground based instrumentation.
Last Modified: 04/01/2016
Modified by: Carlos Martinis
