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Research

Space Environment Technologies (SET) personnel are active in several space physics research areas:

Solar Irradiance Forecasting, Data Assimilation, and Visualization

New Solar Irradiance Proxies for Operational Space Weather

Seven new solar proxies have been developed since 2000 to characterize the energy input into operational space physics models. The E10.7 index is produced for solar energy input into empirical thermospheric and ionospheric model applications that use the F10.7 proxy. The Qeuv thermospheric heating rate was developed for use in studies that compare airglow-derived versus solar-derived upper atmosphere heating while the Peuv was created to provide the EUV hemispheric power index as a complement to the auroral hemispheric power index. Tinf is the subsolar point dayside exospheric temperature that complements the Jacchia nighttime minimum exospheric temperature and is applicable to long-term climate change studies. SET produces a derived sunspot number, Rsn, for use by operational HF radio ray-trace algorithms and provides the integrated solar spectrum, S, that is used for solar radiation pressure calculations related to spacecraft attitude control. The E1_40 index is the integrated EUV energy flux from 1-40 nm that compares with the derived EUV energy from satellite observations of terrestrial airglow, especially that produced by the O/N2 observations.

Qeuv Heating rate

Qeuv heat rate for the Earth thermosphere near solar maximum.Tinf subsolar dayside exospheric temperature compared to Jacchia nightside minimum exospheric temperature

 

Tinf subsolar dayside exospheric temperature compared to Jacchia nightside minimum exospheric temperature.


Forecasting of Space Environment Parameters for Satellite and Ground System Operations

Improvements in the near-term forecasting of E10.7 and F10.7 with SET's first generation forecasting algorithms have been demonstrated and are in the form of reduced 1-sigma uncertainties from 11% to 8% for the 3-day forecast. These algorithms, which have largely relied on linear predictive algorithms, are now being modified to include new physical and mathematical insights into operational forecasting for longer forecast timeframes through SET's second generation forecast algorithms. These specify solar variability on seven time scales from nowcast out to 5 solar cycles using solar east limb observations, interplanetary hydrogen backscattering from the solar far-side, and solar dynamo theory. For example, the 7-21 day improved forecast will eventually use the SOHO SWAN Lyman-alpha data which is the reflected solar farside irradiance from the interplanetary hydrogen at about 3 AU on the other side of the Sun relative to the current Earth position. Using these “mirrored” solar irradiances makes an improvement over linear predictive techniques when compared to the actual irradiances values. In addition, Ken Schatten’s dynamo theory solar cycle forecasts are now used to improve the timing of long-term forecasts compared to the statistical solar cycle mean used in the first generation forecasts. Continuous wavelet transforms are used to provide self-consistency between blended forecast time frames. In general, second generation forecasting is marked by the use of measurements or physics rather than linear prediction algorithms to specify future solar irradiance values.

E10 and F10 Forecast Comparison

Improved E10 and F10 72-hour forecasts

SOHO SWAN images and SET predictions

SOHO SWAN team image of the solar far-side, their predictions of F10.7 and Lyman-alpha, and SET first generation predictions prior to Oct 31 2003 large events.

Schatten

Schatten's solar dynamo method of predicting solar proxies out to five solar cycles.

E10 CWT

Continuous wavelet transforms applied to historical and forecast solar proxies


Earth thermosphere and ionosphere research

Developments in Coupling Irradiances with the Thermosphere and Ionosphere

Improvements to solar irradiance spectral and temporal characterizations have enabled couplings with physics-based models of the Earth thermosphere and ionosphere. When SOLAR2000 spectral irradiances are used as solar energy inputs into physics-based thermospheric density models such as 1DTD, we are able to see the solar cycle minimum to maximum change in mass densities on long and short term time scales that affect satellites. It is possible that these densities are changing over time (decreasing) due to cooling of the thermosphere from carbon dioxide and methane that may be convectively mixed from lower atmosphere layers to the upper atmosphere. SOLAR2000 is also being coupled with the GAIM ionosphere model to produce a climatological best-estimate of ionospheric parameters. The electron density field is then modified by globally measured total electron content (TEC) data to produce a more accurate global and local specification of the terrestrial ionosphere.

 

Earth thermospheric densities from solar minimum to maximum produced with modeled SOLAR2000 spectral irradiances and the 1DTD physics-based model.

GAIM TEC

TEC as produced by the USC/JPL GAIM model using solar spectral irradiances as one of the climatological inputs.


Jupiter atmosphere research

SET has participated with a broad science community on Jovian upper atmosphere research through the NASA Galileo mission.


SET research personnel

Dr. Kent Tobiska is an Air Force Principal Investigator (PI) for the Operational Ionospheric Forecast System SBIR, is a NASA PI for the LWS, SOHO, JSDAP, and UARS programs, and is a Co-Investigator (Co-I) on NASA SDO, TIMED, Galileo, and ESA component of the International Space Station (ISS) SOL-ACES instruments. He was the co-chair of the 1993 IAU Colloquium #143 “Sun as a variable star,” is currently a panel chair for the ICSU/SCOSTEP International Solar Cycle Study Working Group 1.2 “Variations in FUV/EUV/XUV/Energetic Particle fluxes,” is the COSPAR C1 Sub-Commission (Thermosphere & Ionosphere) Vice-Chair, the COSPAR International Reference Atmosphere (CIRA) Task Force Vice-Chair, and was a Main Session Organizer for ISO space environment standards session at the 2002 World Space Congress. He serves as lead U.S. delegate to ISO for the space environment and for developing a solar irradiance standard; he is the AIAA ASETC Committee on Standards chair. He has authored or co-authored 60 peer-review scientific papers as well as 7 books and major technical publications. Dr. Tobiska is a member of American Geophysical Union, Committee On Space Research, and the American Institute of Aeronautics and Astronautics.

Mr. Dave Bouwer has over twenty years experience specializing in the development of systems for research and operations, working on all parts of the systems development life cycle from concept and design, to application programming, documentation, systems management, user support, and project management. His specialty is the transition of research models and data assimilation algorithms, including legacy code, into operational systems. His scientific experience includes basic solar-terrestrial research in solar irradiance at X-ray and UV wavelengths, ionospheric and magnetospheric physics, satellite orbital mechanics, satellite data analysis, and time-and-frequency domain analysis. He has developed aerospace, oil/gas geological, and CAD/CAM systems. Recently, he was instrumental in transitioning two space physics models into operations at the NOAA/SEC Space Forecast Center by using Java to encapsulate models and legacy code as well as to manage data communications.