AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 1
Neutral Atmosphere Density Interdisciplinary Research: (NADIR)
A Multidisciplinary University Research Initiative (MURI)Sponsored by the Air Force Office of Scientific Research
The objective of NADIR is to significantly advance understanding of drag forces on satellites, including density, winds, and factors affecting the drag coefficient.
We seek a level of understanding that will enable specification and prediction at the “next level” of performance.
Actual Position
Predicted Position
Co-Principal Investigators: Jeff Forbes and Tim Fuller-RowellUniversity of Colorado at Boulder
Aug 2007 - Aug 2012 $7.2 M
http://ccar.colorado.edu/muri/
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 2
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 3
NADIR Participants
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Co-Investigators• Rashid Akmaev,• Brian Argrow,• George Born,• Geoff Crowley,• David Falconer,• Delores Knipp, USAFA• Juan Fontenla,• Tomoko Matsuo,• Dusan Odstrcil,• Joachim Raeder, • Jeff Thayer,
DoD Oversight
Kent Miller, AFOSR; Joseph Liu, AFSPC; Robert McCoy, ONR
Collaborators
• Jeffrey Anderson, NCAR• Eugene Avrett, Harvard-SAO• Christopher Bass, AFSPC• Bruce Bowman, AFSPC• Gary Bust, UTSA• Mihail Codrescu, SEC, NOAA• Doug Drob, NRL• Irene Gonzalez-Hernandez, NSO• Cheryl Huang, AFRL• Chin Lin, AFRL• Charles Lindsey, Co-RA• Frank Marcos, AFRL• Matthew McHarg, USAFA• Craig McLaughlin, U Kansas• Cliff Minter, NGA• Steve Nerem, CU• Andrew Nicholas, NRL• Jens Oberheide, U Wuppertal• Vic Pizzo, SEC, NOAA• Eric Quemaris, CNRS• Arthur Richmond, NCAR• Stan Solomon, NCAR• Thomas Woods, CU
AdministrationSarah Melssen, CU
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 4
1000 km
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 5
NADIR Methodology
• Better understand the physical processes
• Determine which of the processes create structure on a scale that is importantto satellite drag.
• Determine the driver-response relationships - internal and external.
• Improve forecasts of the drivers.• Determine the most valuable datasets required
to specify the system state and forecast the drivers
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 6
Eight Focus AreasI. Scales of Density Variability, Winds, and Drag
Prediction:
What spatial and temporal scales of drag variability are most relevant to in-track error?
II. Internal Processes and Thermosphere-Ionosphere Coupling:
CHAMP Densities
How do cooling processes regulate the response and recovery of magnetic storms?
What is the impact of T-I coupling on the neutral density structure?
What is the source of the semiannual variation and its solar cycle dependence?
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 7
Eight Focus AreasIII. Energy Partitioning at High Latitudes and Density
Implications
How is magnetospheric energy input partitioned (Joule heating, momentum transfer, etc.) and what are the implications for density and density-driver-relationships?
IV. Wave Forcing from the Lower Atmosphere
What are the meteorological influences on thermosphere density, and can a predictive capability be developed?
-- Joule Heating
-- Density
(Geoff Crowley - Numerical Experiments Using TIMEGCM Model)
4 hr delay
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 8
Eight Focus AreasV. Forecasting
Geomagnetic Activity
Objective: Use observations in the
photosphere, corona, at L1 and
numerical models of the heliosphere and magnetosphere to:
(1) Improve existing empirical and numerical models of the heliosphere and geospace; and
(2) Achieve more realistic short-term and
probabilistic long-term forecasting.
• Forecasting Solar EUV/UV Radiation
Objective: Develop EUV & UV solar flux forecastsup to a few weeks using:
• near-side solar observations and • far-side helio-seismological and L-scattering observations
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AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 9
Eight Focus AreasVII. Driver-Response
Relationships
What are the dominant modes of density variability, and how do they relate to the drivers?
VIII. Satellite Drag in the Transition Region
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Utilize Direct Simulation Monte Carlo (DSMC) methods to simulate andunderstand drag coefficient changesIn the re-entry regime (ca. 150-90 km).
Use tidal theory, wind and temperatureObservations to model density variability in the re-entry regime.
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 10
Research Highlight:Rotating Solar Coronal Holes and Periodic
Modulation of the Upper Atmosphere
Lei, J., Thayer, J.P., Forbes, J.M., Sutton, E.K., and R.S. Nerem, Rotating Solar Coronal Holes and Periodic Modulation of the Upper Atmosphere, Geophys. Res. Lett., in press, 2008.
Thayer, J.P., Lei, J., Forbes, J.M., Sutton, E.K., and R.S. Nerem, Thermospheric Density Oscillations due to Periodic Solar Wind Fast Streams, J. Geophys. Res., in press, 2008.
Lei, J., Thayer, J.P., Forbes, J.M., Sutton, E.K.,Nerem, R.S., Temmer, M., and A.M. Veronig, Periodic oscillations in thermospheric density measured by the CHAMP satellite during the declining phase of solar cycle 23, J. Geophys. Res., submitted, 2008.
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 11
During declining and low solar activity, multiple rotating coronal holes produce periodic high-speed solar wind streams.
At Earth, these high-speed streams modulate geomagnetic activity in the geospace environment with the same periodicity.
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 12
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Thermosphere Density - 400 km
F10.7
Solar Wind Speed
Kp
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 13
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TIMED/SEE
Thermosphere Density - 400 km
F10.7
Solar Wind Speed
Kp
Spectra for all of 2005
A triad of coronal holes during 2005 leads to a27d/3 = 9d periodicity inthermosphere density
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 14
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Density at 400 km
An element of predictability is inherent in this phenomenon!
Latitude Structure of Density ResponseA: Actual Data B: Band-Pass Filtered Data
Percent density change
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 15
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27d/3 = 9.0
27d
Thermosphere Density - 400 km
F10.7
Solar Wind Speed
Kp
Thermosphere Density - 400 km
27d/4 = 6.8
27d/2 = 13.5
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google: ‘asen-5335’
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Additional SlidesMore Details of Focus Areas
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Focus Area I: Scales of Density Variability, Winds, and Drag Prediction
Forbes, Born, McLaughlin, Thayer, Fuller-Rowell
Methodology: A test bed of satellites will be used to perform satellite orbit predictions, and to evaluate predicted versus actual in-track satellite positions (“in-track errors”) in terms of characteristics of density variability (e.g., scale size).
Anticipated Outcome: Understand what spatial and temporal resolutions that both empirical and first-principles models should seek to achieve, as well as the required temporal resolution of geophysical indices or data that drive the models.
Sample Question: What spatial and temporal scales of drag variability are most relevant to in-track error?
Objectives
• Gain quantitative knowledge and a deeper understanding of how prediction error depends on the various facets of density variability.
• Connect our scientific research activities to the actual prediction of satellite ephemerides.
CHAMP Densities
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 19
Sample Questions:
• What is the impact of T-I coupling on the neutral density structure?
• What is the source of the semiannual variation and its solar cycle dependence?
• How do cooling processes regulate the response and recovery of magnetic storms?
Focus Area II: Internal Processes and Thermosphere-Ionosphere Coupling
Fuller-Rowell, Forbes, Thayer, Codrescu, Crowley, Solomon, Richmond
Relationship between and Ne - from CHAMP
Objective: Attain improved understanding of internal processes, and capture this understanding in the next generation of hybrid empirical/physical models.
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 20
Focus Area III: Energy Partitioning at High Latitudes and Density Implications
Thayer, Fuller-Rowell, Codrescu, Crowley, Knipp, Forbes, Richmond
Objectives
• Improve scientific understanding of the high latitude energy input; energy partitioning into other forms; neutral density and wind responses to these high latitude energy inputs.
• Develop driver-response relationships to improve empirical model specifications.
Methodology: Numerical experiments to evaluate solar flux production of electron density and the concomitant change in the Joule heating rate; assess impact on global temperatures and density. Perform similar numerical experiments using empirical relations with kinetic energy flux and Poynting flux.
Anticipated Outcome: Understand the correlations amongst the fluxes to develop driver-response relationships that may depend on multiple energy sources .
Sample Question: In what ways are the solar flux, kinetic energy flux and Poynting flux related?
00
12
0618
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Sample questions
• What are the observed characteristics?
• How are they connected to dynamical variations in the strato-mesosphere?
• Can PW-period density variations be empirically accounted for in models such as J70 and JB2006?
• Can PW periodicities in density be reliably predicted with whole-atmosphere models on time scales of ~one to two weeks in advance?
Focus Area IV: Wave Forcing from the Lower Atmosphere
Akmaev, Forbes, Fuller-Rowell
Objectives
• Delineate density variations at planetary-wave (PW) periods (2-20 days) and understand their origin.
• Develop driver - response relationships to enable predictive capability.
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008
Focus Area V: Forecasting Geomagnetic ActivityOdstrcil, Pizzo, Falconer, Raeder, Fuller-Rowell
Methodology: Use observations in the photosphere (left-top), corona (left-bottom), at L1 (bottom-center), and numerical models of the heliosphere (top-center) and magnetosphere (right).
Anticipated Outcome: Improved forecasting ability with the lead times: 30-60 min: driving magnetospheric models by L1 observations; 1-3 days: driving heliospheric models by coronal observations; 3-5 days: using probability of solar magnetic eruptions.
Objectives: Improve existing empirical and numerical models of the heliosphere and geospace to achieve more realistic short-term and probabilistic long-term forecasting.
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Focus Area VI: Forecasting Solar EUV/UV Radiation
Fontenla, Woods, Avrett, Quemaris, Lindsey
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Objective
• Develop forecasts of EUV and UV solar flux variability up to a few weeks in advance.
Methodology
• Using various measurements of solar properties on the near-side (Earth-facing) part of the Sun, models of the solar atmosphere, and existing empirical relationships, construct solar spectra or “masks”for 10 positions on the solar disk each day.
• Validate against SORCE and other measurements.
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• Use helio-seismological and L scattering observations of the far-side of the Sun to apply corrections to the “obsolete”parts of the mask. (Active regions change since the last time they were seen on the near-side)
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AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 24
AFOSR MURI: Neutral Atmosphere Interdisciplinary Research (NADIR) • Space Weather Workshop, 2008 25
Focus Area VIII: Satellite Drag in the Re-Entry Region:Satellite Drag
Brian Argrow and Jeff Forbes
Motivation
• Accurate CD essential for drag prediction
• DSMC can be applied for transition flow regime
• Gas surface interaction models are the source of most error for current CD computations
Methodology: Application of the Direct Simulation Monte Carlo (DSMC) for vehicle simulations from free-molecular flow to slip-flow regimes with emphasis on the gas-surface interaction model.
Anticipated Outcome: Data base of altitude-dependent CD values for representative satellite geometries. Simulate aerodynamic forces for trajectory analysis
DSMC Simulations of a Hypersonic Waverider at 100 km and 145 km (density contours)
100 km 145 km
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Focus Area VIII: Satellite Drag in the Re-Entry Region:Tidal and Longitude Variations in Density
Jeff Forbes and Jens Oberheide
Motivation
• Re-entry prediction an important problem.
• Few density measurements exist at re- entry altitudes (ca. 80-200 km)
• Strong longitude variations in tides known to exist in temperature and wind measurements
Methodology: A fitting scheme using “Hough Mode Extensions” will be applied to TIMED/SABER and TIMED/TIDI measurements of temperatures and winds over 80-120 km and -50o to +50o latitude during 2002-2006.
Anticipated Outcome: global specifications of longitude-dependent tidal variations in density, winds, and temperature over the 80-200 km height region.
Reconstructed Density Diurnal Amplitudes 110 km, September 2005
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