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LWS TR&T Focus Teams:

Short Term Solar/Atmospheric Variability and Climate

Team Leader:
Team Research Plan:
Next Team Meeting: TBD
Team-Maintained Web Site: TBD
Team Publications: TBD
Team Members:

Target Description: Both observations and models demonstrate that short-term solar variations can produce significant effects in Earth’s upper, middle, and lower atmosphere. Impulsive solar events, such as x-ray flares and solar energetic particles, occur on times scales of minutes to days that is very short compared to climatological time scales. Despite their short duration, these phenomena produce intensity changes at short wavelengths and in the energetic particle populations of several orders of magnitude, leading to dramatic changes in atmospheric response, often localized in space, time, or both.

As elucidated in "The Effects of Solar Variability on Earth's Climate: A Workshop Report" (NAP press, publication 13519, ISBN-10: 0-309-26564-9), a key question remains, namely, where does the role of short-term solar variability (both at short wavelength and in energetic particle populations) fit into the larger effort to understand the influence of the Sun on climate? Although total solar irradiance is the main solar driver of climate variability, whether, and by what mechanisms shorter-time-scale variations have an impact on climate are presently unclear.

The goal of this Focused Science Topic is to develop understanding of the complex response of the atmosphere to these short-term solar variations in order to know how these effects translate into the historical records of solar variability and their long-term impacts on climate. We presently have unprecedented observations of these nonvisible elements of solar variability (short wavelength solar photons and solar energetic particles) and of the atmosphere, which responds to these highly-variable solar drivers. We also now have modeling capabilities to explore the complex interactions and responses throughout the affected portions of the atmosphere to the inputs. If we can quantify these short-term responses through combined model development and data validation, then this knowledge can be used to address the more subtle, but potentially important, slow variation of these same drivers, and the atmosphere’s response occurring on climatological timescales.

Goals and Measures of Success: The goal of this Focused Science Team is to advance our understanding of the short-term responses of the atmosphere to impulsive solar events, such as flares and solar particles by:

- Progress in quantifying the range and sensitivity of the atmosphere’s complex response to rapid inputs of energy in the form of x-ray flares and solar particles.
- Progress in understanding what aspects of the flares and solar energetic particles (intensity, duration, spectral shape, etc.) control the atmosphere’s response and what other factors might control the response (such as prior condition of the atmosphere).
- Use of modern observations to validate and calibrate models, which in turn can be used to explore recent historical trends of these drivers and their predicted responses.
- Progress on how to extend our knowledge on the short-time scale, to address the slower variability of these same mechanisms occurring on climatological time scales.

Types of Investigations:

- Numerical models of atmospheric responses to a full range of impulsive solar energetic particles and flare photon inputs.
- Integration of observations of actual impulsive inputs and atmospheric models, combined with models, to establish the complex response function and its sensitivity to input and boundary parameters.
- Validated models to explore and to quantify whether longer-term variations in these rapid-timescale phenomena contribute to climate variability.

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