TR&T resourcesTR&T main pageTR&T proposalsTR&T resourcesTR&T newsTR&T related sitesTR&T contacts LWS main page NASA main page

LWS TR&T Focus Teams:

Determine and Quantify the Responses of Atmospheric/Ionospheric Composition and Temperature to Solar XUV Spectral Variability and Energetic Particles

Team Chair: Elsayed Talaat
Next Team Meeting:
Team-Maintained Web Site:
Team Publications:
Team Members:

Liying Qian
Aaron Ridley
Tim Fuller-Rowell
Phil Richards

Target Description: With the recent availability of comprehensive solar spectral measurements at X-ray and ultraviolet (XUV) wavelengths, together with upper atmospheric chemistry and transport models, quantification of the full range of solar effects on chemically active minor constituents and ion composition in the ionospherethermosphere- mesosphere (I-T-M) system is now possible. Additional solar-driven variation is caused by the energetic particle environment, ranging from auroral fluxes to galactic cosmic rays. These sources have important influences on the chemistry, energetics, and dynamics of the lower thermosphere and ionosphere (e.g., on nitric oxide and ozone) via direct energy deposition and modulation of ion-neutral frictional heating. Observations of neutral composition and temperature for different phases of the solar cycle and for sporadic events are available through NASA missions like the Upper Atmosphere Research Satellite (UARS) and the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission (TIMED), as well as from other space- and groundbased instruments. Observations of ionospheric electron density are available through a variety of sources. In view of these advances, models of atmospheric/ionospheric composition and energetics that fully exploit the available estimates of external energetic inputs can now be developed to more accurately quantify solar effects in the middle and upper atmosphere.

Goals and Measures of Success: The goal of this topic is to determine how well our understanding of atmospheric/ionospheric processes, as incorporated in state-of-the-art models, is able to explain observed compositional and temperature effects in the middle and upper atmosphere caused by external energetic inputs, in order to be able to predict these effects under both normal and extreme conditions. The measure of success will be the ability to obtain closure between observations and models of short-term, solar-cycle, and long-term variability as functions of altitude.

Types of investigations:
• Development of global and regional process models and the application of such models to assess the response of the I-T-M system to variable energy inputs;
• Data analyses that provide new descriptions of external energy drivers;
• Observational studies that characterize atmospheric/ionospheric composition and temperature responses to energetic inputs; and
• Development of models that use data assimilation to reproduce past conditions as a test, and then use them to forecast future conditions and to make a case for certain ongoing observations.

TR&T main page LWS main page TR&T proposals TR&T news TR&T related sites TR&T contacts TR&T resources NASA main page





TR&T main page LWS main page TR&T proposals TR&T news TR&T related sites TR&T contacts TR&T resources NASA main page



LWS Post-Doc Program TR&T Tools and Methods TR&T Stategic Capability TR&T Focus Teams TR&T Steering Committee Heliophysics Summer School