GUVI Global Ultraviolet Imager                                 

HOME

OVERVIEW

EXTENDED MISSION

USING GUVI DATA

GUVI DATA PRODUCTS

SUMMARY IMAGES

PUBLICATIONS

EDUCATION

 

 

 

 

 

 

Overview of TIMED Extended Mission

For the past four years, TIMED has been extremely productive, rapidly fulfilling its promise as an anchor in the Sun-Solar System Connections (S3C) Great Observatory (GO) and as a bridge to Earth Science missions. During this period, TIMED has observed the impact on the structure of the Ionosphere-Thermosphere-Mesosphere (ITM) system of varying solar EUV radiation and X-ray flares, geomagnetic storms powered by solar coronal mass ejections, and powerful high-speed solar wind streams during activity levels ranging from high at solar maximum to moderate in the declining phase.  TIMED has additionally documented the effect of stratospheric weather on the ITM structure. These investigations have addressed many open science questions that straddle the boundaries between the ITM and the lower atmosphere on the one end and between the ITM and the space environment on the other. In particular, during a series of strong geomagnetic storms and solar particle events, TIMED observations were combined with data from other missions to examine the ITM structure and the energy balance from the solar inputs through the magnetosphere and down to the lower atmosphere for the first time. An important feature emerging from TIMED discoveries during these first four years is that the system response to multiple drivers, including upward propagating inputs from the lower atmosphere, is not just the linear superposition of responses to individual drivers. The whole is clearly different from the sum of the parts. 

This proposal requests four more years of operations and one additional year of data analysis to further investigate the interconnections of the geospace environment and the internal physical processes and preconditioning that make the ITM an active element in this coupling. The extended mission will occur during the ascending phase of the solar cycle, exploring the system response to a new regime in the balance between solar irradiance and magnetic forcing. These observations will add a valuable view of the system at a time when solar magnetic activity is reaching a 22-year minimum and the balance between geomagnetic and upwardpropagating influences is shifting in the sensitive MLT region. As the F10.7 rises toward solar maximum values, geomagnetic activity will remain low. This is in contrast to the descending phase of the solar cycle (which characterized much of the previous TIMED observations), in which geomagnetic activity was exceptionally high owing to the presence of powerful, recurrent, high-speed streams and associated corotating interaction regions (CIRs) as the F10.7 spanned the range from solar maximum to solar minimum values. This change in the balance of radiant to geomagnetic forcing will reveal interesting details about the interplay between atmospheric preconditioning and the ITM response to forcing from above and below. In particular, energy inputs from the lower atmosphere are expected to be relatively more important during this phase of the solar cycle. 

TIMED observations are designed around a powerful strategy for instrument operations that is well suited to achieve the proposed mission goals. TIMED consists of four instruments that routinely make the same observations day in and day out. The circular orbit of TIMED has a specific, carefully chosen inclination that allows all local solar times to be sampled over a 60-day period in a repeatable pattern. Thus, TIMED has the ability to see the atmosphere in the very same way from year to year; only the external drivers and preconditioning change. This strategy enables TIMED to perform key comparative studies that isolate the effects of different drivers on the system response. For example, the longer database collected during the extended mission will enable the separation of solar inputs that vary with solar cycle from other influences. It is also important to note that the instrument capabilities designed into the mission provide TIMED with a 3D view of the temporal evolution of the ITM system, a tremendous leap beyond the capabilities of the AE, DE, SME, and UARS missions and a significant tool for investigations of the coupling within the system, which varies with both altitude and geographic location. Finally, by extending its mission, TIMED will observe the truly quiescent state of the upper atmosphere at different solar irradiance levels for the first time. As can be appreciated, characterizing the quiescent state of the ITM system provides critical information about the ground state and boundary conditions of this nonlinear, coupled system.

TIMED observations have revealed new features of the ITM response to drivers, provided new insights into details of the coupling between drivers, and raised intriguing new questions.  These system level issues are at the frontier of ITM research and at the heart of NASA’s Sun-Solar System Connection (S3C) Science and Technology Roadmap 2005-2035.  Progress on this frontier not only brings new knowledge of the natural systems surrounding Earth that are necessary for space weather prediction but will go beyond this to provide detailed information on aeronomical processes necessary for predictive models of atmospheric global change at Earth as well as for the development of more sophisticated models of other planetary atmospheres. 

As mankind prepares to take the first steps on Mars, NASA will need robust models of the martian atmosphere’s response to forcing from above and below. The terrestrial upper atmosphere is a natural laboratory within which to investigate the same basic physical processes that shape the climate, variability, and evolution of the martian atmosphere.  Lessons learned from the Sun-Earth system research support the design of cost-effective and highscience-value Mars missions as ecommended in the S3C Roadmap [Yee et al., 2004].  Global models that simulate the elements in the Sun-Earth system are excellent tools for unraveling the emergent behaviors, the coupling between system elements, and the nonlinear features that constitute the system-level response, but only if they are tied closely to observations. TIMED is prepared to meet the challenges of coupling data sets across discipline areas and establishing closer ties than ever before by proactively developing interfaces between TIMED observations and the coupled models. 

During its extended mission, TIMED will carry out a comprehensive research plan that involves current and future GO data and modeling assets to address emerging science topics most relevant to the S3C science research focus areas.

 		  

 The Johns Hopkins University Applied Physics Laboratory                             The Last Updated: October 17, 2005