Solar Influences on Global Change (1994) / Chapter Skim
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7 RESEARCH STRATEGIES
7 RESEARCH STRATEGIES
Pages 111-134
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From page 111... ...
Ultimately, the ability to predict past and future solar influences will derive from improved knowledge of the origins of solar variability. This slate of activities, in the broadest sense, encompasses much of the domain of solar-terrestrial relations.
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From page 112... ...
In acquiring a suite of solar irradiance measurements with sufficient long term precision for global change research, important aspects of space based solar metrology obtained from the experiences of the 1980s must be used to guide research strategies for the 1990s and beyond.
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From page 113... ...
Total Solar Trradiance The detection of solar luminosity variability during solar cycles 21 and 22, and the interpretation of this variability in terms of solar magnetic activity, thus far underscores the need to extend the solar irradiance data base indefinitely with maximum possible precision. The data are needed for the forseeable future to reduce the uncertainties in the detection of anthropogenic climate forcing.
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From page 114... ...
Rather than including essential solar monitoring instrumentation as part of complex space platforms that inevitably suffer delays, a series of small, overlapping satellite missions dedicated to monitoring solar irradiance variability will likely prove to be a more reliable strategy for obtaining the requisite data for global change research. Solar Spectral Trradiance Obtaining an unbroken, reliable record of the Sun's UV irradiance variations will require an approach similar to that identified for total
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From page 115... ...
Because of the paucity of plans for future solar UV spectral irradiance measurements, the preferred strategy would be to include instruments to measure both spectral and total irradiance on a series of overlapping solar monitoring satellites. If possible, instruments that measure changes in the
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From page 116... ...
irradiance variability models for use in studying solar forcing of the upper atmosphere (Smith et al., 1993~. Even if adequate flight opportunities can be established for solar irradiance instrumentation, a data base with sufficient accuracy for establishing the variability of solar UV energy inputs to the Earth will only be achieved through a continued commitment to innovative radiometric programs dedicated to the improvement of absolute measurement accuracies.
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From page 117... ...
Additional measurements of energetic particle input and the atmospheric response should continue to be made with the suborbital and NOAA programs. Ground Based Solar Variability Indicators A number of existing ground based solar observing programs have proven, over the past decade, to be extremely valuable and cost effective for studying solar influences on global change, and these programs should be continued indefinitely.
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From page 118... ...
Where possible, spectral irradiance observations should also be made -- for example, observations of the UV emission of these Sun-like stars. Indirect records related to solar variability have been provided for many decades by measurements of the Earth's magnetic field from global ground based magnetometer networks.
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From page 119... ...
The need to monitor the stratosphere is also important for global change research in its own right within the Biogeochemical Dynamics science element, because of the existence of the stratospheric ozone layer, and this is discussed more extensively in the following section. Global monitoring of the solar ultraviolet radiation reaching the biosphere is relevant for studying solar influences on global change as well as for the Ecological Systems and Dynamics science element of the USGCRP; both involve changes in middle atmosphere ozone.
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From page 120... ...
However, it must also be recognized that determining solar influence on the middle atmosphere requires global measurements over not just one but several solar cycles, at least. In addition to ozone, measurements of nitrogen oxides (NO, NO2, HNO3)
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From page 121... ...
, DoD and ISTP programs will be adequate for providing the long term data base. Upper Atmosphere Like the state of knowledge of the relevant solar energy inputs, global information on the responses of the thermosphere and ionosphere system to solar forcing faces a dearth of observational programs.
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From page 122... ...
The dearth of long term studies of the Earth's upper atmosphere from space platforms places greater responsibility on ground based observations and in particular on NSF's CEDAR program, which was originally identified with NSF's Global Geoscience Program and is, again, principally focused on process studies. Thus the activities pursued as part of CEDAR should be extended enough to study the long term and global scale phenomena important for understanding and predicting global change.
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From page 123... ...
This will ultimately require combining climate and middle atmosphere models to construct extended three-dimensional models with complete, coupled radiation, chemistry and dynamics. Investigations using improved models may then lead to new understanding of the potential solar cycle/weather relationships that are not simulated by existing climate or middle atmosphere models alone.
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From page 124... ...
With respect to understanding solar influences on the upper atmosphere and possible indirect forcing of global change, numerical models of physical and chemical processes and global circulation of the coupled thermosphere-ionosphere-mesosphere system should be developed and used to investigate the effects of solar terrestrial couplings on global change. These models should also consider the effects of anthropogenic forcing, such as CO2 and CH4 increases, on the properties and dynamics of the upper atmosphere.
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From page 125... ...
This will require a program to use and combine many paleoclimate indicators, such as those derived from tree rings, glaciers, pollen, and corals. Surrogates for solar irradiance variations are needed here in particular, if any connection between the decacial to century scale climatic oscillations and solar variability is to be proven.
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From page 126... ...
As orbital variations represent our most quantifiable solar insolation changes, they provide tools both for quantifying climate sensitivity and for validating climate models on long time scales. UNDERSTANDING AND PREDICTING SOLAR VARIABILITY Acquiring a reliable data base of solar energy inputs to the Earth through the next decades is essential for monitoring and understanding solar forcing of global change.
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From page 127... ...
The irradiance variations must be physically connected to the fundamental cause of solar variability, which is solar magnetic activity, to achieve the ultimate goal of prediction. Until the data base of solar EUV spectral irradiance observations has been augmented substantially, significant improvements in the simple empirical models that predict EUV irradiance variations from solar activity proxies will not be possible.
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From page 128... ...
If adequately funded, RISE could also provide future support for the analysis and interpretation of the historical solar image data base of contemporary ground based data relevant to understanding the Sun as a variable star and of the terrestrial pathways and processes through which solar variations might impact global change. The ongoing Global Oscillation Network Group (GONG)
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From page 129... ...
properly formulated to include both direct and indirect UV effects on the middle atmosphere the lower atmosphere and the couplings between. This in turn calls for interdisciplinary collaboration.
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From page 130... ...
There is also a clear relationship to Biogeochemical Dynamics. Solar variations are known to affect the middle atmosphere, and these effects must be considered when looking for trends in stratospheric ozone.
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From page 131... ...
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From page 132... ...
NSF has long supported basic research into Solar-Terrestrial Physics - how solar changes affect the terrestrial environment. NSF also supports theoretical and observational solar research, primarily using ground based techniques.
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From page 133... ...
encourages use of DoD resources for global change research. In this regard, the Defense Meteorological Satellite Program could provide regular access to space for solar monitoring and global change endeavors.
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From page 134... ...
Both of these international programs include components involving solar influences on global change. The International Solar Terrestrial Physics Program (ISTP)
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