TIGER: A program for thermospheric-ionospheric geospheric research

The primary goals of the TIGER Program as defined in current knowledge of t he terrestrial thermospheric-ionospheric (T/I) system are presented in this Special Edition of the Journal Physics and Chemistry of the Earth. The 1(s t) and the 2(nd) TIGER Symposia were held in Freiburg (1998) and in St. Pet ersburg (1999), respectively, and the participants decided to summarize thi s field of space research combining the results of both symposia in a revie w-type survey. The TIGER Program was established within the framework of the SCOSTEP Inter national Solar Cycle Study, Working Group 1, Panel 2. This decision is base d on the general agreement that the improvement of existing thermospheric-i onospheric (T/I) models is absolutely necessary to meet scientific and engi neering goals for thermospheric-ionospheric research as well as for a broad range of commercial applications in space. There are also a number of scie ntific questions underlying the goal of understanding solar EUV/UV variabil ity such as what are the primary mechanisms by which solar ultraviolet (UV) , extreme ultraviolet (EUV), and soft X-ray (XUV) irradiance variations aff ect terrestrial global climate change, including the upper atmosphere and s pace weather. The improvement of T/I models requires coordinated work on the following to pics: Measurement and modeling of solar EUV/UV radiation EUV/UV Space Instrumentation Modeling of the solar wind originated energy T/I influx and Space Weather T/I modeling and measurement of relevant T/I parameters from space Measurements from ground Basic physical investigations to support T/I modeling to make substantial p rogress in developing a more complete understanding of the T/I processes, i t is necessary to envisage solar cycle and even longer timescales. This can be done in the global change context by making use of a broad range of wor ldwide existing resources with respect to manpower, experience, hardware, m ethods, flight opportunities, and funding resources. The TIGER Program aims to facilitate the coordination of these existing and planned activities an d to help define missing links for achieving the scientific goals. (C) 2000 Elsevier Science Ltd. All rights reserved.