ALBERT

Description: In order to systematically and thoroughly study the crust-mantle structure and deep geodynamic processes of basins, mountains and plateaus of western China, we proposed and led the implementation of the ANTILOPE Project (Array Network of Tibetan International Lithospheric Observation and Probe Experiments) in 2003. So far, we have completed four 2D broadband arrays, ANTILOPE-I to ANTILOPE-IV, on the Tibetan Plateau, and deployed two 3D broadband arrays, ANTILOPE-V and ANTILOPE-VI, at the eastern and western Himalayan syntaxis, respectively. In addition, we included in our study framework nine comprehensive geophysical observation profiles previously obtained from the Junggar Basin, Tienshan Orogenic Belt, Tarim Basin, Altyn Orogenic Belt, and Qaidam Basin. Through the implementation of the ANTILOPE Project, we collected a large amount of high-quality, comprehensive first-hand observational data from western China (including the basin-mountain system surrounding the Tibetan Plateau in the northwest and the Tibetan Plateau in the southwest). The fine crust-mantle structure systematically reveals the deep geodynamic processes of the basin-mountain-plateau geosystem in western China. The up-to-date main research progress can be summarized as follows. The structure and properties of the basement of the Junggar Basin have been determined, and the basement structural framework has been optimized. A new intracontinental orogenic model of lithospheric subduction with crustal interlayer intrusion in the Tienshan Orogenic Belt has been established, which reveals the fate of the 44% shortened Tienshan lithosphere after the India-Eurasia collision and the conversion mechanism from ocean-continent subduction to continent-continent collision and subduction. Our results reveal the basin-mountain contact relationship between the Tarim Basin, Altyn Orogenic Belt and Qaidam Basin. We have obtained the deep geometric, kinematic and geodynamic evidence for the clockwise rotation of the Tarim Basin, and determined the collision boundary between the Indian and the Eurasian Plates under the Tibetan Plateau. We also found that the current Tibetan Plateau consists of the Indian Plate in the south, the Eurasian Plate in the north, and the giant crush zone-also called the "Tibetan Plate"-between them. For the first time, the respective lithospheric bottom boundaries are determined; two end-member models of plateau deformation are corrected; and the constraints of deep structures on the surface topography are established. Our result systematically reveals the changing pattern and controlling factors of the horizontal advancing distance and the subduction angle of the Indian Plate along the Himalayan Orogenic Belt. By combining a huge observation network with comprehensive geophysical detection technologies, the ANTILOPE Project adopts different methods, including geophysical, geological and geochemical methods, to reveal the subduction of the Indian continent, the development of the giant crush zone in Tibet, the clockwise rotation of the Tarim Block, the accelerated closure of the western water vapor channel, and the advance of aridification and desertification in northwest China and their constraints on surface topography, oil and gas resources, and environmental variations. The above results have promoted the development of the Earth system theory in the Tibetan Plateau. © 2021, Editorial Office of Earth Science Frontiers. All right reserved.

Description: Day-to-day variability is an intricate aspect of the ionosphere and thermosphere (IT) system. Its ubiquitous but random presence makes it difficult to track down and hard to predict, presenting a serious challenge for both theoretical understanding and space weather forecasting. We currently understand the day-to-day variability as being externally driven by three different forces: (1) solar radiation, (2) solar wind/geomagnetic storms, and (3) upward propagating atmospheric waves generated in the meteorological regime. This chapter reviews the characteristics of day-to-day variability revealed in recent years. We note that our knowledge on the day-to-day variability is highly limited, and a systematic picture of such variability across an array of major IT parameters (e.g., plasma density and drift, thermosphere density, wind, and temperature) is yet to be achieved. We identify several key issues that warrant future effort: (1) How to systematically quantify day-to-day variability of the global IT system, (2) how does the day-to-day variability in key IT parameters change in space and evolves with time, (3) what is the time lag pertaining to IT response to solar radiation at different timescales, (4) what are the relative contributions to IT short-term variability from different drivers, (5) what is the thermospheric day-to-day variability driven by upward propagating waves, and (6) does the IT system have any internally driven day-to-day variability?