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Superrefraction at the top of the atmospheric boundary layer introduces problems for assimilation of radio occultation data in weather models. A method of detection of superrefraction by spectral analysis of deep radio occultation signals introduced earlier has been tested using 2 years of COSMIC-2/FORMOSAT-7 radio occultation data. Our analysis shows a significant dependence of the probability of detection of superrefraction on the signal-to-noise ratio, which results in a certain sampling nonuniformity. Despite this nonuniformity, the results are consistent with the known global distribution of superrefraction (mainly over the subtropical oceans) and show some additional features and seasonal variations. Comparisons to the European Centre for Medium-Range Weather Forecasts analyses and limited set of radiosondes show reasonable agreement. Being an independent measurement, detection of superrefraction from deep radio occultation signals is complementary to its prediction by atmospheric models and thus should be useful for assimilation of radio occultation data in the atmospheric boundary layer.

 

The present topography of the northern Tibetan Plateau is characterized by the northwest-trending Eastern Kunlun Range, Qaidam Basin, and Qilian Shan, which figure importantly into the evolution and mechanism of Tibetan plateau development during Cenozoic Indo-Asian convergence. Understanding the Cenozoic deformation history and the source-to-sink relationship through time has significant implications for deciphering the growth history of the northern Tibetan Plateau. Despite decades of study, the timing, pattern, and mechanisms of deformation across the northern Tibetan Plateau are still vigorously debated. The North Qaidam thrust belt, located between the Qaidam Basin and Qilian Shan thrust belt, provides a valuable record of Cenozoic deformation in the northern Tibetan Plateau. Here, we present the results of new geologic mapping, structural and sedimentology analysis, and apatite fission track thermochronology to constrain the Cenozoic evolution history and reconstruct the paleogeomorphology of the eastern domain of the North Qaidam thrust belt and its foreland, the Wulan Basin. Our analyses reveal the North Qaidam thrust belt experienced multi-phase exhumation since the Cretaceous. A period of Eocene localized thrust-related uplift of the North Qaidam thrust belt initiated shortly after India-Asia collision, and lower erosion rates in the Oligocene allowed the thrust belt to expand along-strike eastward. Local uplift shed sediments to the southwest, directly into the Qaidam Basin. Reactivation of the proximal thrust faults and initiation of the northwest-striking right-slip Elashan fault at ca. 15−10 Ma drove the final accelerated mid-Miocene cooling and denudation to the surface. This phase of deformation established the overall framework morphology of the northeastern margin of the Tibetan Plateau, including the overall structure of the basins and ranges. 

Lecture-based teaching paired with laboratory-based exercises is most commonly used in cybersecurity instruction. However, it focuses more on theories and models but fails to provide learners with practical problem-solving skills and opportunities to explore real-world cybersecurity challenges. Problem-based Learning (PBL) has been identified as an efficient pedagogy for many disciplines, especially engineering education. It provides learners with real-world complex problem scenarios, which encourages learners to collaborate with classmates, ask questions and develop a deeper understanding of the concepts while solving real-world cybersecurity problems. This paper describes the application of the PBL methodology to enhance professional training-based cybersecurity education. The authors developed an online laboratory environment to apply PBL with Knowledge-Graph (KG) based guidance for hands-on labs in cybersecurity training.Learners are provided access to a virtual lab environment with knowledge graph guidance to simulated real-life cybersecurity scenarios. Thus, they are forced to think independently and apply their knowledge to create cyber-attacks and defend approaches to solve problems provided to them in each lab. Our experimental study shows that learners tend to gain more enhanced learning outcomes by leveraging PBL with knowledge graph guidance, become more aware of cybersecurity and relevant concepts, and also express interest in keep learning of cybersecurity using our system. 

Abstract An unprecedented extreme positive Indian Ocean Dipole event (pIOD) occurred in 2019, which has caused widespread disastrous impacts on countries bordering the Indian Ocean, including the East African floods and vast bushfires in Australia. Here we investigate the causes for the 2019 pIOD by analyzing multiple observational datasets and performing numerical model experiments. We find that the 2019 pIOD is triggered in May by easterly wind bursts over the tropical Indian Ocean associated with the dry phase of the boreal summer intraseasonal oscillation, and sustained by the local atmosphere-ocean interaction thereafter. During September-November, warm sea surface temperature anomalies (SSTA) in the central-western tropical Pacific further enhance the Indian Ocean’s easterly winds, bringing the pIOD to an extreme magnitude. The central-western tropical Pacific warm SSTA is strengthened by two consecutive Madden Julian Oscillation (MJO) events that originate from the tropical Indian Ocean. Our results highlight the important roles of cross-basin and cross-timescale interactions in generating extreme IOD events. The lack of accurate representation of these interactions may be the root for a short lead time in predicting this extreme pIOD with a state-of-the-art climate forecast model.