| 英文摘要: | The proposed project involves the construction and calibration of a pair of Super-DARN radars at a single site in central Ireland. The two SuperDARN radars, with a combined field-of-view exceeding ±75 in azimuth centered on the magnetic meridian, will be capable of making measurements of the ionospheric electric field over a region that includes eastern North America, Greenland, Iceland, Scandinavia and western Russia. Measurements in this sector, currently limited to the region north of 65 latitude, will extend the capabilities of the SuperDarn network to provide near real-time maps of the convection electric field during an expanded range of geomagnetic activity levels and increase the local time (LT) coverage to more than 12 hours. Existing radars at similar latitudes have demonstrated the importance of measurements from radars located at mid-latitudes during quiet to more active geomagnetic conditions and in particular, the ability of these radars to make detailed measurements of the sub-auroral polarization stream (SAPS) on rapid timescales (<1 min) over an extended range (>8 hours LT). The installation of the two SuperDarn radars in Ireland would make possible investigations of longitudinal differences associated with the South Atlantic Anomaly in SAPS and electric field structuring as well as conjugate studies with southern hemisphere radars. In line with the geospace community review panel recommendations, distributed networks of ground-based instruments are quite valuable in resolving space-time ambiguities associated with sparse measurements of the space environment and making progress toward the science goals of the Solar Wind-Magnetosphere Interactions. The Ireland radars will significantly increase measurements of the electric field at mid-latitudes enabling SuperDARN to provide real-time observations of space weather disturbances in the ionosphere extending from Asia, across North America and into Northern Europe. This should result in significant progress toward the larger goal of providing the capability to predict the effects of solar variability on the environment and on society.
An important aspect of the proposed project is the calibration of SuperDARN elevation angle measurements which can be used to improve the geolocation of backscattered signals, to discriminate between propagation modes and to estimate the index of refraction at the scattering location - this is now normally done by modeling using ray tracing software, and such models might be in error at times.
The project includes a small augmentation that will enable one of the interferometer arrays to be configurable and allow for testing of the sensitivity and accuracy of SuperDARN interferometers. Ireland is ideally situated for interferometer testing with two Scandinavian ionospheric heating facilities providing a calibration source within the field-of-view of the augmented radar. The project would very efficiently reuse most of a ready-to-go radar system that for various logistical and political reasons never got installed in the Azores. This is a highly targeted re-purposed application that minimizes substantially the installation budget. |