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Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations
Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations
Outline
Outline
Uncertainties in solar Irradiances create uncertainties in
Uncertainties in solar Irradiances create uncertainties in
Photoelectron Observations
Photoelectron Observations
Model Data Comparison
Model Data Comparison
Transformation to Equivalent Wavelength
Transformation to Equivalent Wavelength
Relative Difference Observation - Model / Model as a Function of the
Relative Difference Observation - Model / Model as a Function of the
FAST Observations from August 31 to September 30 2005
FAST Observations from August 31 to September 30 2005
Differences between Observations and Model PE Energy Spectra over a
Differences between Observations and Model PE Energy Spectra over a
Observation-Model Differences -2
Observation-Model Differences -2
Solar Irradiance Models Differ at Many Wavelengths
Solar Irradiance Models Differ at Many Wavelengths
Irradiance Power above and below 27 nm
Irradiance Power above and below 27 nm
Irradiance Spectral Models
Irradiance Spectral Models
Conclusions
Conclusions

Презентация: «Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations of Solar EUV Irradiance Models». Автор: MacP108 LASP. Файл: «Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations of Solar EUV Irradiance Models.ppt». Размер zip-архива: 4334 КБ.

Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations of Solar EUV Irradiance Models

содержание презентации «Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations of Solar EUV Irradiance Models.ppt»
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1 Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations

Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations

of Solar EUV Irradiance Models

W.K. Peterson1, J.M. Fontenla1, T.N. Woods1, P.G. Richards2, S.C. Solomon3, H.P. Warren4, W.K. Tobiska5, and P.C. Chamberlin6 1LASP/CU, 2George Mason, 3NCAR/HAO, 4NRL, 5Utah State, 6NASA/GSFC

Peterson, MURI, October 2003

2 Outline

Outline

Our method to compare photoelectron energy observations and irradiance models Comparisons of photoelectron energy spectra with those predicted with two photoelectron production codes driven by the SPRM predictive model, and the FISM, HEUVAC, S2000, and NRL irradiance models Conclusions: Surprisingly the empirical HEUVAC (EUVAC extended to 1 nm) model produces photoelectron spectra that match the observations on daily and solar rotation period time scales. The SRPM prediction model matches the data as well or better than any of the data or index driven models. The physics based NRLEUV model does the poorest job of capturing the variation of energetic photoelectrons on a solar rotation time scale.

Peterson, MURI, October 2003

3 Uncertainties in solar Irradiances create uncertainties in

Uncertainties in solar Irradiances create uncertainties in

thermospheric models

Altitude-wavelength dependence of energy deposition from solar irradiance in units of Log10(Wm-4) From Solomon and Qian 2005 Solar minimum conditions

Color Bar: Log10(Wm-4)

Peterson, MURI, October 2003

4 Photoelectron Observations

Photoelectron Observations

FAST observations available from January 1, 1997 to April 30, 2009 ePOP observations available in late 2011

Peterson, MURI, October 2003

5 Model Data Comparison

Model Data Comparison

Average of 56 one-minute average spectra obtained for SZA < 90o Two PE production codes Seven Solar irradiance models

Peterson, MURI, October 2003

6 Transformation to Equivalent Wavelength

Transformation to Equivalent Wavelength

Use a constant15 eV ionization potential

Peterson, MURI, October 2003

7 Relative Difference Observation - Model / Model as a Function of the

Relative Difference Observation - Model / Model as a Function of the

Wavelength Equivalent of the Photoelectron Energy

S/N inadequate below ~3 nm (> 385 eV) Above ~16 nm differences are less than +/- 50% Above ~30 nm slight differences in PE’s predicted from the GLOW and FLIP models.

* GLOW/HEUVAC best agrees with observations

Both the GLOW and FLIP codes show TIMDED/SEE irradiances systematically low below about 15 nm

Peterson, MURI, October 2003

8 FAST Observations from August 31 to September 30 2005

FAST Observations from August 31 to September 30 2005

Observed Photoelectron flux vs. Energy (eV)

Vs. Equivalent Wavelength (nm)

Each line in the color spectrogram panels shows a daily average photoelectron energy spectra with the flux given by the color bars on the right.

F10.7

KP

F10.7

AP

DST

Peterson, MURI, October 2003

9 Differences between Observations and Model PE Energy Spectra over a

Differences between Observations and Model PE Energy Spectra over a

Solar Rotation

Observation - Model / Model RED: Model >200% Low GREEN: Model = Obs BLACK: No data

HEUVAC

SPRM- Rome

SPRM- MLSO

FISM

S2000

NRLEUV

Photoelectron energy spectra produced using the empirical HEUVAC model agree best with Observations. The SPRM predictive model does as well as the TIMED/SEE based FISM model

Peterson, MURI, October 2003

10 Observation-Model Differences -2

Observation-Model Differences -2

HEUVAC

SPRM- Rome

SPRM- MLSO

FISM

S2000

NRLEUV

FISM produces good agreement except for underestimating the PE fluxes between 5 and 15 nm

S2000 produces low fluxes below 15 nm and relatively good agreement above 15 nm.

NRLEUV systematically underestimates the photoelectron flux below 15 nm

RED: Model >200% Low GREEN: Model = Observations BLACK: No data

Peterson, MURI, October 2003

11 Solar Irradiance Models Differ at Many Wavelengths

Solar Irradiance Models Differ at Many Wavelengths

Irradiance models are qualitatively different above and below ~27 nm

SPRM- Rome

SPRM- MLSO

HEUVAC Model Color Bar is Irradiance in w/m2

HEUVAC

Relative Differences are (Model - HEUVAC) / HEUVAC

FISM

S2000

NRLEUV

F10.7

RED: Model >400% than HEUVAC Green: Model = HEUVAC

Peterson, MURI, October 2003

12 Irradiance Power above and below 27 nm

Irradiance Power above and below 27 nm

Lowest: NRLEUV Highest: HEUVAC/S2000

Lowest: HEUVAC/NRL Highest: SPRM

Photoelectron spectra produced using HEUVAC agree best with data

Peterson, MURI, October 2003

HEUVAC

SPRM-Rome

SPRM-MLSO

FISM

S2000

NRLEUV

13 Irradiance Spectral Models

Irradiance Spectral Models

HEUVAC model has by design has broad spectral structure (~1eV) above 27 nm To first order all models agree about the spectral shape below 27 nm The most significant differences between irradiance models are in the relative power above and below 27 nm.

Peterson, MURI, October 2003

HEUVAC

SPRM-Rome

SPRM-MLSO

FISM

S2000

NRLEUV

14 Conclusions

Conclusions

Surprisingly the empirical HEUVAC (EUVAC extended to 1 nm) model produces photoelectron spectra that best match the observations on daily and solar rotation period time scales. Fontenla’s SRPM prediction model matches the photoelectron data as well or better than any of the other data or index driven models investigated. The physics based NRLEUV model does the poorest job of capturing the variation of energetic photoelectrons on a solar rotation time scale. We need SDO/EVE observations to fully understand the temporal and spectral variations of solar irradiance.

Peterson, COSPAR, 2010, C12-0018

«Photoelectrons as a Tool to Evaluate Spectral and Temporal Variations of Solar EUV Irradiance Models»
http://900igr.net/prezentacija/anglijskij-jazyk/photoelectrons-as-a-tool-to-evaluate-spectral-and-temporal-variations-of-solar-euv-irradiance-models-90036.html
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