ALBERT

Description: At high‐latitudes, diurnal and semidiurnal variations of temperature and neutral wind velocity can originate both in the lower atmosphere (UV or infrared absorption) and in the thermosphere‐ionosphere (ion convection, EUV absorption). Determining the relative impact of different forcing mechanisms gives insight to the vertical coupling in the ionosphere. We analyze measurements from the incoherent scatter radar (ISR) facility operated by the EISCAT Scientific Association. They are complemented by meteor radar data and compared to global circulation models. The amplitudes and phases of tidal oscillations are determined by an adaptive spectral filter (ASF). Measurements indicate the existence of strong semidiurnal oscillations in a two‐band structure at altitudes ≲110 and ≳130 km, respectively. Analysis of several model runs with different input settings suggest the upper band to be forced in situ while the lower band corresponds to upward‐propagating tides from the lower atmosphere. This indicates the existence of an unexpectedly strong, in situ forcing mechanism for semidiurnal oscillations in the high‐latitude thermosphere. It is shown that the actual transition of tides in the altitude region between 90 and 150 km is more complex than described so far.

Description: Plain Language Summary: Solar and atmospheric variability influence the ionosphere, causing critical impacts on satellite and ground‐based infrastructure. Determining the dominant forcing mechanisms for ionosphere variability is important for prediction and mitigation of these threats. However, this is a challenging task due to the complexity of solar‐terrestrial coupling processes. Tidal oscillations (mostly 12 and 24‐hr periods) allow for a rough estimations of whether forcing from “above” or “below” dominates. The classical understanding is that 12‐hr oscillations propagate upwards from below while 24‐hr oscillations are forced at high altitudes. We analyze data from two radar systems and three global ionosphere models and show that the altitude structure of tidal oscillations is in fact more complex than classically assumed.

Description: Key Points: Twenty‐day long EISCAT radar campaign shows a complex mixture of semidiurnal and diurnal tidal oscillations. Three global circulation models show similar tidal structuring and allow to determine the influence of different forcing mechanisms. Adaptive spectral filtering (ASF) technique allows robust fitting of tidal amplitudes and phases.

Description: EISCAT

Description: JSPS KAKENHI

Description: DFG

Description: https://doi.org/10.5281/zenodo.6817130

Description: https://doi.org/10.5281/zenodo.7072141

Description: Tidal wind oscillations in the high-latitude ionospheric dynamo/transition region can be in situ forced or propagate there from lower atmospheric layers. Investigating the complex mixing of tidal modes allows determining the solar, geomagnetic, and atmospheric impact on the transition region dynamics. In classical tidal theory at high latitudes, semidiurnal tides forced by UV and IR absorption in lower atmospheric regions propagate upwards and are the dominant tidal mode up to about 120 km. Above, diurnal modes forced in situ by EUV absorption and ion drag due to the polar plasma convection are assumed dominant. We analyze a 22-day-long measurement campaign with the EISCAT UHF incoherent scatter radar during September 2005. The beam-swinging experiment allows for obtaining neutral winds from 96 - 142 km altitude which are combined with simultaneous Kiruna meteor radar measurements. An Adaptive Spectral Filtering technique is applied to determine tidal amplitudes and phases. The zonal wind showed the expected transition from semidiurnal to diurnal oscillations at about 120 km. The meridional wind showed a more complex structure with dominant 12h oscillations below 110 km and above 130 km. General Circulation Model runs with different forcing settings are analyzed to determine the origin of these high-altitude semidiurnal oscillations. The measured asymmetry of tidal amplitudes in zonal and meridional winds is found in all investigated model runs. It is shown that at high latitudes, atmospheric tides do not influence semidiurnal oscillations above 120 km. The polar ion convection and EUV absorption both contribute to the observed high-altitude semidiurnal oscillations.

Description: Evaluating the embodied environmental impact of solar photovoltaic (PV) technology has been an important topic in addressing the sustainable development of renewable energy. While monetization of environmental externality is a remaining issue, which should be carried out in order to allow for an easy-to-understand comparison between direct economic and external cost. In this study, the environmental impact of solar PV power is monetized through conversion factors between midpoint and endpoint categories of life cycle analysis and the monetization weighting factor. Then, the power generation capacity and generation life of PV and coal-fired power plants are assumed to be consistent in order to compare the total cost of PV and coal-fired power generation. Results show that the cost of PV technology is higher than coal-fired in 2026 to 2030, taking into account environmental external costs and production costs. However, by 2030, the total cost of coal-fired power will be higher than that of solar PV. The life span cost per kWh is $3.55 for solar PV and $116.25 for coal-fired power. Although solar PV power seems more environmentally effective than coal-fired power in the life span, our results reveal the high environmental external cost of producing solar photovoltaic modules, which reminds us to pay more attention to the environmental impact when conducting cost-benefit analysis of renewable technologies. Without incorporating the environmental cost, the real cost of renewable technology will be underestimated.

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: The deep crustal deformation in the east Pamir in response to the Cenozoic collision with the Tien Shan and the Tarim Basin is so far poorly constrained. We present new insights into the crustal structure of the east Pamir and its surrounding regions using P receiver functions from 40 temporary and permanent seismic stations. The crustal thickness reaches a maximum of 88 km beneath the central and southern east Pamir and decreases sharply to 50–60 km along the southern Tien Shan and to 41–50 km below the Tarim Basin. The most prominent crustal structures involve a double Moho, suggesting eastward underthrusting of the Pamir lower crust beneath southern east Pamir, and two Moho offsets, supporting delamination of Asian lower crust below the central east Pamir and pure shear shortening along the northeastern margin between the Pamir and Tarim Basin.

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?

Description: The lower-thermosphere–ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric part of the LTI is dominated by laws of continuum fluid dynamics and chemistry, while the ionosphere is a plasma system controlled by electromagnetic forces driven by the magnetosphere, the solar wind, as well as the wind dynamo. The LTI is hence a domain controlled by many different physical processes. However, systematic in situ measurements within this region are severely lacking, although the LTI is located only 80 to 200 km above the surface of our planet. This paper reviews the current state of the art in measuring the LTI, either in situ or by several different remote-sensing methods. We begin by outlining the open questions within the LTI requiring high-quality in situ measurements, before reviewing directly observable parameters and their most important derivatives. The motivation for this review has arisen from the recent retention of the Daedalus mission as one among three competing mission candidates within the European Space Agency (ESA) Earth Explorer 10 Programme. However, this paper intends to cover the LTI parameters such that it can be used as a background scientific reference for any mission targeting in situ observations of the LTI.

Description: The Budyko framework with a synthetic parameter that encodes the impacts of various factors can be used to separate the runoff changes. The key is to identify the relationship between the Budyko parameter and the impact factors. Here, a clustering method called FCM and a hierarchical Bayesian model were used. The results were as follows. 44 basins of the Yangtze River Basin can be clustered into five clusters based on 10 factors of climate (P, T, and SI), vegetation (M), soil (KC), topography (ELEV, SLP, and TWI), and human activities (IRR and B). Hierarchical Bayesian models can improve the estimations of Budyko parameter by considering the impacts of spatial correlations of multiple factors, compared with linear regression models. Their R2, RB, and RMSE for the whole YZRB were as follows: 0.9104 versus 0.7591, 4.33% versus 8.21%, and 0.06 versus 0.11, respectively. Results of impact factor decomposition showed that precipitation was the main cause of runoff changes in each cluster, and it led to changes exceeding 3.20% in runoff while the influence of potential evapotranspiration was little. Rising temperature caused runoff to decrease by more than 7.90% in Cluster 1, 3, and 4. In addition, precipitation seasonality, vegetation, and irrigation water consumption had different influences in different clusters. This study improves the ability of the Budyko framework to quantitatively decompose impacts of various factors on regional runoff changes and provides more reasonable suggestions for water resource management.