Asian Sector Research Articles

Detection of Extensive Equatorial Plasma Depletions After the 2022 Tongan Volcanic Eruption From Multiple Geodetic Satellite Ranging Systems

AbstractWe present a number of unique observations of ionospheric anomalies following the Hunga‐Tonga Hunga‐Ha'apai (HTHH) volcanic eruption on 15 January 2022. All are based on non‐dedicated geodetic satellite systems: Global Positioning System tracking of Low Earth Orbit (LEO) CubeSats, intersatellite tracking between two GRACE Follow‐On satellites, satellite radar altimeters to the ocean surface, and Doppler radio beacons from ground stations to LEO geodetic satellites. Their observations revealed the development of anomalously large trough‐like plasma depletions, along with plasma bubbles, in the equatorial regions of the Pacific and East Asian sectors. Trough‐like plasma depletions appeared to be confined within approximately ±20° magnetic latitude, accompanied by density enhancements just outside this latitude range. These plasma depletions and enhancements were aligned with the magnetic equator and occurred across broad longitudes. They were detected in regions where atmospheric waves from the HTHH eruption passed through around the time of the sunset terminator. We interpret these phenomena in terms of the E dynamo electric fields driven by atmospheric waves from the eruption. The uplift of the ionosphere beyond satellite altitudes, followed by subsequent plasma diffusion to higher latitudes along magnetic field lines, results in the formation of trough‐like plasma depletions around the magnetic equator and density enhancement at higher latitudes. The detection of plasma bubbles in the Asian sector during the non‐bubble season (January) is likely associated with the uplift of the ionosphere at the sunset terminator.

Agricultural trade liberalization, governance quality, and technical efficiency in the agricultural sector of Southeast Asia

International trade has been regarded as an essential factor in enhancing a country's productivity and efficiency. Nevertheless, developing countries squander money and resources as a result of their deficient institutional quality, impeding their ability to profit from specialization and trade. Therefore, this study intends to investigate the impact of agricultural trade liberalization and governance quality on technical efficiency in Southeast Asia's agricultural sector using balanced panel data spanning from 2002 to 2021. The research utilizes translog stochastic frontier analysis (SFA) with a single-stage maximum likelihood estimation (MLE) to simultaneously calculate the time-varying technical efficiency scores and explore the core factors influencing agricultural inefficiency. The findings reveal that the average output-oriented technical efficiency for ASEAN-8 countries was 94 %. This suggests that there is significant potential to enhance technical efficiency in agricultural production by up to 6 % by addressing the adverse impacts of technical inefficiency. The research findings further point out that Malaysia is the most technically efficient country, having a technical efficiency score of 99.82 %, followed by Vietnam (99.75 %), Thailand (99.70 %), Lao PDR (98.90 %), Myanmar (95.42 %), Indonesia (91.64 %), the Philippines (90.65 %), and Cambodia (76.11 %). The results of disaggregated agricultural trade liberalization demonstrate a significant reduction in agricultural inefficiency in Southeast Asia through agricultural exports and imports. The findings also emphasize that improvements in the rule of law positively contribute to agricultural efficiency, whereas enhancements in terms of voice and accountability and regulatory quality appear to reduce it. Based on these findings, the government should consider enlarging open and liberalized trade policies in order to facilitate the exchange of technology and knowledge within the agriculture sector. Additionally, the government should involve farmers, agricultural cooperatives, local communities, and other relevant stakeholders in the decision-making process to ensure that policies address the specific needs and constraints faced by the sector.

Definition and recommendations of advance care planning: A Delphi study in five Asian sectors.

In Confucian-influenced Asian societies, explicit end-of-life conversations are uncommon and family involvement in decision-making is crucial, which complicates the adoption of culturally sensitive advance care planning. To develop a consensus definition of advance care planning and provide recommendations for patient-centered and family-based initiatives in Asia. A five-round Delphi study was performed. The rating of a definition and 84 recommendations developed based on systematic reviews was performed by experts with clinical or research expertise using a 7-point Likert scale. A median = 1 and an inter-quartile range = 0-1 were considered very strong agreement and very strong consensus, respectively. The Delphi study was carried out by multidisciplinary experts on advance care planning in five Asian sectors (Hong Kong/Japan/Korea/Singapore/Taiwan). Seventy-seven of 115 (67%) experts rated the statements. Advance care planning is defined as "a process that enables individuals to identify their values, to define goals and preferences for future medical treatment and care, to discuss these values, goals, and preferences with family and/or other closely related persons, and health-care providers, and to record and review these preferences if appropriate." Recommendations in the domains of considerations for a person-centered and family-based approach, as well as elements, roles and tasks, timing for initiative, policy and regulation, and evaluations received high levels of agreement and consensus. Our definition and recommendations can guide practice, education, research, and policy-making in advance care planning for Asian populations. Our findings will aid future research in crafting culturally sensitive advance care planning interventions, ensuring Asians receive value-aligned care.

ПЕРСПЕКТИВИ ЕКСПОРТУ АГРОПРОДОВОЛЬЧОЇ ПРОДУКЦІЇ З УКРАЇНИ ДО КРАЇН АЗІЇ

The article considers current state of Ukraine's export of agri-food products to Asian countries, detailing its commodity and geographic structure. General socio-economic characteristics of the Asian region have been carried out. The main principles of the functioning of the agro-food sector in Asia in relation with its production and foreign trade are given. The largest exporters and importers of food among Asian countries have been determined according to the latest available data. Total agricultural trade of our country with China, India and Turkey highlighted. The dynamics of bilateral sectoral trade between partners and the key products of Ukrainian production supplied to their markets are considered. Further emphasis placed on the import needs of those food groups or commodity items by the specified countries, which Ukraine is already able to satisfy to a certain extent. An assessment of the impact of war and its negative consequences on the actual exports indicators from Ukraine to Asia during 2022-2023 was carried out. The importance of finding new sales markets and consolidating existing partner trade relations by concluding agreements on free trade was emphasized. It is pointed out the actual impossibility for our exporters to fully use the transport and logistics infrastructure, which affects the quantitative and qualitative indicators of foreign sales. In fact, against the background of the final decline in export revenues, the redirection of products from Asia to the markets of European Union does not have the proper effect and does not compensate for the losses incurred. Development prospects and opportunities for optimizing Ukrainian agri-food exports to Asian markets were given, taking into account the sector's limited resources, short- and medium-term priorities of our industry producers, and existing requests of specific importing countries.

Development of the Chinese Dual Auroral Radar Network and Preliminary Results

AbstractLed by the National Space Science Center of the Chinese Academy of Sciences, we have built a Chinese dual auroral radar network in northern China, which is called the CN‐DARN. The CN‐DARN consists of three pairs of high‐frequency coherent scattering radar facilities and is one of the key parts of the Chinese Meridian Project Phase II. It has been fully constructed and started trial operations at the end of 2023. The detection range of the radar network extends longitudinally over approximately 9 hr of local times and covers the middle to high latitudes of the entire Asia region above 40. In this paper, we present the basic design of the CN‐DARN and its preliminary observations of ionospheric irregularities, subauroral polarization streams (SAPSs) and traveling ionospheric disturbances (TIDs). We also investigate its contribution to the ionospheric convection pattern of the Northern Hemisphere derived from Super Dual Auroral Radar Network (SuperDARN) observations. The results indicate that the CN‐DARN provides excellent measurements and better specifications of flows in the Asian sector, improving our understanding of the global‐scale ionospheric convection pattern in the Northern Hemisphere. These encouraging results lead us to believe that the CN‐DARN will play an important role in studies on the evolution of ionospheric irregularities, the characteristics and evolution of SAPSs, the propagation of TIDs, and global‐scale ionospheric convection dynamics.

Implications for extreme midlatitude weather events of secondary flow associated with polar jets

AbstractIn the Earth's general circulation, polar jets act as baroclinic pumps of angular momentum and heat. Reanalysis datasets indicate that shear changes near jets induce upward displacements of the jet cores, suggesting a weakening thermodynamic pumping over the last 50 years. From secondary flow theory, a well‐established principle in fluid dynamics, an increased frequency of heatwaves and persistent winter storms is expected. The ageostrophic wind shear between 700 and 50 hPa indicates the strength of this secondary circulation. The weakening tendency during the reanalysis period also exists in multimodel simulations under the RCP8.5 emissions scenario for the 21st century. The reduction between the periods 2005–2025 and 2081–2100 reaches 18%, 5.3% and 19%, respectively, for the North America, Mid‐Europe and East Asia sectors of the Northern Hemisphere polar jet. Within this background, cold‐surge events are the result of synergic co‐working of several factors. The occurrence trend for transitional season winter extreme events also is examined. The winter extremes seemingly have larger temperature drops. However, in a warming climate, they emerge more rapidly from extreme cold states. The storm tracks, especially over North America, have equatorward extensions, indicating that winter storms can reach lower latitudes. Due to the temperature‐dependence of air viscosity, secondary flows decrease more slowly than the main zonal flow. This imposes an important adjustment to the traditional polar amplification effects on midlatitude winter extremes. During a warmer winter (the primary manifestation of a warmer climate), spatially uniform positive trends in cold extreme events are not expected. There are, however, regions experiencing more winter extremes. These regions show consistent patterns in both the reanalysis period and the remainder of the 21st century.

Observational Overview of the May 2024 G5-Level Geomagnetic Storm: From Solar Eruptions to Terrestrial Consequences

This study reports comprehensive observations for the G5-level geomagnetic storm that occurred from May 10 to 12, 2024, the most intense event since the 2003 Halloween storm. The storm was triggered by a series of coronal mass ejections (CMEs) originating from the merging of two active regions 13664/13668, which formed a large and complex photospheric magnetic configuration and produced X-class flares in early May 2024. Among the events, the most significant CME, driven by an X2.2 flare on May 9, caught up with and merged with a preceding slower CME associated with an X-class flare on May 8. These combined CMEs reached 1 AU simultaneously, resulting in an extreme geomagnetic storm. Geostationary satellite observations revealed changes in Earth’s magnetosphere due to solar wind impacts, increased fluxes of high-energy particles, and periodic magnetic field fluctuations accompanied by particle injections. Extreme geomagnetic storms resulting from the interaction of the solar wind with the Earth’s magnetosphere caused significant energy influx into Earth’s upper atmosphere over the polar regions, leading to thermospheric heating and changes in the global atmospheric composition and ionosphere. As part of this global disturbance, significant disruptions were also observed in the East Asian sector, including the Korean Peninsula. Ground-based observations show strong negative storm effects in the ionosphere, which are associated with thermospheric heating and resulting in decreases in the oxygen-to-nitrogen ratio (O/N2) in high-latitude regions. Global responses of storm-time prompt penetration electric fields were also observed from magnetometers over the East-Asian longitudinal sector. We also briefly report storm-time responses of aurora and cosmic rays using all-sky cameras and neutron monitors operated by the Korea Astronomy and Space Science Institute (KASI). The extensive observations of the G5-level storm offer crucial insights into Sun-Earth interactions during extreme space weather events and may help establish better preparation for future space weather challenges.

Occurrence rate of equatorial Spread F and GPS ROTI in the ionospheric anomaly region over Vietnam

This paper presents the first observations of the occurrence rates of Spread F and GPS total electron content (TEC) index (ROTI) over Vietnam at the equatorial trough and the northern tropical crest of ionization anomaly in the Asian sector. The data have been examined for the monthly and nighttime variations in the occurrence of these two data at Bac Lieu (9.28°N, 105.73°E, dip: 1.73°N) and Phu Thuy (21.03°N, 105.95°E, dip: 14.49°N) during 2023. For Bac Lieu, the monthly variation in the occurrence of the range Spread F (RSF) has the maxima in the February, May, and September months, while the mixed Spread-F (MSF) and ROTI occurrences exhibit a semiannual asymmetry with peaks in March/April and October. For the nighttime variation, occurrence peaks at 1915-1930 LT for RSF, at about 1945-2100 LT for MSF, and between 2030-2330 LT for ROTI. Regarding the frequency Spread F (FSF) occurrence, the maximum values in the monthly variation are in April, and the nighttime variation peaks at about 2115-2315 LT. For Phu Thuy, the monthly variation of RSF, MSF, and ROTI occurrences also exhibit a semiannual asymmetry with peaks in March/April and October. These peak magnitudes are largest for ROTI, moderate for MSF, and smallest for RSF. The nighttime variation of RSF, MSF, and ROTI occurrence peaks show intense season changes from winter to autumn at pre-midnight, spring at post-midnight, and summer at post-midnight. The FSF occurrences are more significant in summer than in other seasons, mainly after midnight. The time order appearance of the Spread F types at Bac Lieu and Phu Thuy is first of RSF, then MSF, and finally FSF. This could reflect that the formation mechanisms of Spread F types are different and require further research. Our observations also showed that the post-midnight occurrence of Spread F is much larger than ROTI at Bac Lieu and Phu Thuy. The monthly variations in occurrence rates of Spread F and ROTI at Bac Lieu and Phu Thuy are similar, but these occurrence rates at Bac Lieu are usually larger than at Phu Thuy.

A Review of the Energy System and Transport Sector in Uzbekistan in View of Future Hydrogen Uptake

This study explores the potential role of hydrogen in decarbonizing the transport sector in Uzbekistan by examining different aspects of the country’s energy system and transport final use. In road transport, Uzbekistan has already gained experience with the use of alternative fuels through the “Compressed Natural Gas—Mobility” initiatives and has achieved a fleet coverage of 59%. These existing frameworks and knowledge can ease the integration of hydrogen into road transport. The rail sector also has the potential for hydrogen uptake, considering that 47% of rail lines are not electrified. The results of this study indicate that powering all CNG vehicles with a 10% hydrogen blend (HCNG) could reduce road transport emissions by 0.62 MtCO2eq per year, while replacing diesel trucks with hydrogen-based vehicles could contribute to an additional reduction of up to 0.32 MtCO2eq per year. In rail transport, hydrogen-powered trains could reduce emissions in non-electrified lines by up to 0.1 kgCO2eq/km of journey. In assessing the potential infrastructure for hydrogen logistics, this study also identifies opportunities for hydrogen export by repurposing the existing natural gas infrastructure. Focusing on Uzbekistan, this study provides a regional perspective on the potential for the integration of hydrogen into the transport sector in Central Asia.

A Comprehensive Classification and Analysis of Geomagnetic Storms Over Solar Cycle 24

A geomagnetic storm is a global disturbance of Earth's magnetosphere, occurring as a result of the interaction with magnetic plasma ejected from the Sun. Despite considerable research, a comprehensive classification of storms for a complete solar cycle has not yet been fully developed, as most previous studies have been limited to specific storm types. This study, therefore, attempted to present complete statistics for solar cycle 24, detailing the occurrence of geomagnetic storm events and classifying them by type of intensity (moderate, intense, and severe), type of complete interval (normal or complex), duration of the recovery phase (rapid or long), and the number of steps in the storm's development. The analysis was applied to data from ground-based magnetometers, which measured the Dst index as provided by the World Data Center for Geomagnetism, Kyoto, Japan. This study identified 211 storm events, comprising moderate (177 events), intense (33 events), and severe (1 event) types. About 36% of ICMEs and 23% of CIRs are found to be geoeffective, which caused geomagnetic storms. Up to four-step development of geomagnetic storms was exhibited during the main phase for this solar cycle. Analysis showed the geomagnetic storms developed one or more steps in the main phase, which were probably related to the driver that triggered the geomagnetic storms. A case study was additionally conducted to observe the variations of the ionospheric disturbance dynamo (Ddyn) phenomenon that resulted from the geomagnetic storm event of 2015 July 13. The attenuation of the Ddyn in the equatorial region was analyzed using the H component of geomagnetic field data from stations in the Asian sector (Malaysia and India). The variations in the Ddyn signatures were observed at both stations, with the TIR station (India) showing higher intensity than the LKW station (Malaysia).

Crossing troubled waters: building a bridge across gender divisions among water professionals in South Asia

This paper examines the reasons for the limited presence of women in the water sector in South Asia and reviews recent efforts at reversing this trend. The reasons for the under representation of women in the sector are the perceived masculine nature of the sector, gender-based discrimination at the work place, and the absence of gender sensitive working environment. A change in the curricula of water education programs from engineering-oriented programs to inter-disciplinary programs and the launch of new inter-disciplinary water resources education programs is likely to reverse this trend. Increased donor interest in this has given a push to such efforts. The launch of new initiatives and programs is likely to increase the number of women water professionals in the near future; however, given the large absolute numbers of men, these numbers would still relatively be low. Financial and administrative support to female students will be necessary to make the water sector more gender sensitive and gender balanced, along with creating conditions that would allow a better expression of women’s interests.

Regional Ionospheric Super Bubble Induced by Significant Upward Plasma Drift During the 1 December 2023 Geomagnetic Storm

AbstractAn unseasonal equatorial plasma bubble (EPB) event occurred in the East/Southeast Asian sector during the geomagnetic storm on 1 December 2023, causing strong amplitude scintillations from equatorial to middle latitudes. Based on the observations from multiple instruments over a large latitudinal and longitudinal region, the spatial features of the super EPB were investigated. The EPB developed vertically at a fast rising speed ∼470 m/s over the magnetic equator and extended to a very high middle latitude more than 40°N, despite that the storm intensity was not very strong with the minimum SYM‐H index −132 nT. In the zonal direction, the super EPB covered over a specific region ∼95–140°E, where the local sunset roughly coincided with southward turning of interplanetary magnetic field (IMF) Bz component. Before the onset of the super EPB, significant upward plasma drift up to ∼110 m/s was observed over the magnetic equator, which could amplify the growth rate of Rayleigh‐Taylor instability and lead to the generation of the super EPB. The significant drift was likely caused by eastward penetration electric field (PEF) due to sharp southward turning of IMF Bz. The local time of storm onset and duration of IMF Bz southward turning during the storm main phase may partly determine the onset region and zonal coverage of the EPB.

Permulaan Gelembung Plasma Khatulistiwa Semasa Angin Neutral Kuat dan Lemah di Asia Tenggara

Equatorial plasma bubbles (EPBs), which are depletions in the ionosphere disrupting radio waves, exhibit complex dynamics influenced by neutral winds. The present study aims to investigate the relationship between the onset of EPBs and the velocities of neutral winds. The onset of EPBs was determined from the rate of the Total Electron Content Index (ROTI) keogram obtained using Global Positioning System (GPS) data over the Southeast Asia sector. Meanwhile, thermospheric neutral winds were measured using a Fabry-Perot interferometer (FPI), and the height of the F layer was acquired from an ionosonde, both instruments positioned in Kototabang (KTB), Indonesia. The observations are classified into two cases based on the strength of winds: strong and weak winds on different nights. This study successfully reported the onset time and location of EPBs occurred at 1320 UT (2120 LT) and 100° (500 km) longitude, attributed to pre-reversal enhancement (PRE). We conclude that thermospheric neutral wind makes a significant contribution to the observed onsets of EPBs driven in the zonal direction. Therefore, this finding reinforces past studies that have shown an increase in the height of the F layer could play an important role in determining the onset of EPBs.

Capital Structure and Financing Decisions in Southeast Asia’s Property and Real Estate Sector: A Systematic Literature Review

This systematic literature review evaluates the existing research on capital structure and financing decisions within the property and real estate sector of Southeast Asia (ASEAN). Despite the sector's dynamic growth and substantial investments, the financial strategies specific to ASEAN remain minimally explored. A methodical review of scholarly articles from ScienceDirect, and Google Scholar spanning from 2000 to 2023. Our analysis identified prevalent themes and trends, notably the application of traditional capital structure theories such as pecking order and trade-off theories to more developed markets. However, the review highlights a significant gap in empirical research focusing on the unique economic, regulatory, and market conditions in ASEAN that crucially impact capital structure and financing choices in the region's property sector. The findings emphasize the need for more targeted empirical studies that account for the socio-economic diversity and specific institutional frameworks of ASEAN countries. These studies aim to enhance understanding of the financing behaviors in their property and real estate markets, thus aiding policymakers and investors in crafting informed strategies and policies.

Multi-Instrument Observation of the Ionospheric Irregularities and Disturbances during the 23–24 March 2023 Geomagnetic Storm

This work investigates the ionospheric response to the March 2023 geomagnetic storm over American and Asian sectors from total electron content (TEC), rate of TEC index, ionospheric heights, Swarm plasma density, radio occultation profiles of Formosat-7/Cosmic-2 (F7/C2), Fabry-Perot interferometer driven neutral winds, and E region electric field. During the storm’s main phase, post-sunset equatorial plasma bubbles (EPBs) extend to higher latitudes in the western American longitudes, showing significant longitudinal differences in the American sector. Over the Indian longitudes, suppression of post-sunset irregularities is observed, attributed to the westward prompt penetration electric field (PPEF). At the early recovery phase, the presence of post-midnight/near-sunrise EPBs till post-sunrise hours in the American sector is associated with the disturbance of dynamo-electric fields (DDEF). Additionally, a strong consistency between F7/C2 derived amplitude scintillation (S4) ≥ 0.5 and EPB occurrences is observed. Furthermore, a strong eastward electric field induced an increase in daytime TEC beyond the equatorial ionization anomaly crest in the American region, which occurred during the storm’s main phase. Both the Asian and American sectors exhibit negative ionospheric storms and inhibition of ionospheric irregularities at the recovery phase, which is dominated by the disturbance dynamo effect due to equatorward neutral winds. A slight increase in TEC in the Asian sector during the recovery phase could be explained by the combined effect of DDEF and thermospheric composition change. Overall, storm-time ionospheric variations are controlled by the combined effects of PPEF and DDEF. This study may further contribute to understanding the ionospheric responses under the influence of storm-phase and LT-dependent electric fields.

Improving waste management strategies in the food sector: case studies from Spain, Tunisia and Hong Kong

Appropriate waste generation and management is becoming increasingly important in making food systems more sustainable. It is, therefore, imperative to both reduce waste generation and sustainably manage the waste that cannot be reduced. However, this is challenging due to the heterogeneity of waste materials, the high economic costs of optimizing food systems and the low awareness of the issue in some societies. This article analyzes three case studies that explore improvements in waste management in the food sector in Europe, Africa and Asia. The case studies focus on a horticultural cooperative in Spain, a seafood company in Tunisia and municipal waste management in Hong Kong, highlighting different challenges and approaches. Key factors for horticultural waste management include a consistent regulatory framework, appropriate management systems and waste traceability. The article also highlights the potential for valorisation of waste products, such as blue crab by-products, which can be used to obtain polysaccharides, proteins, lipids, antioxidants, flavonoids, vitamins and minerals. A shift from landfill to anaerobic digestion is also recommended for a more sustainable waste management. By identifying and quantifying waste streams and problematic waste types, alternative solutions can be developed to improve the sustainability of the global food supply chain.

The Latitudinal and Longitudinal Variation of the Semidiurnal Lunar Tide in the Ionosphere During 2013

AbstractThe present paper studies the latitudinal and longitudinal variation of ionospheric semidiurnal lunar tide (M2) perturbations in 2013 with total electron content (TEC) data. Results show that the latitudinal distribution of M2 exhibits longitudinal difference. At 100 ∼ 120°E and 80 ∼ 100°W longitudes, the strongest M2 perturbations in the northern and southern hemispheres roundly appeared at about 10° ∼ 20°N and 15° ∼ 25°S magnetic latitude (MLAT), respectively, which supports previous suggestion that the M2 maximized in the EIA crest regions. Moreover, the latitude range of M2 at 80 ∼ 100°W longitudes was wider than that at 100 ∼ 120°E longitudes, especially for southern hemisphere (SH). The M2 maximized at 20° ∼ 30°N MLAT in the northern hemisphere (NH) and was absent in the SH at 50°W ∼ 20°E longitudes, which was distinctly different than those at other longitudes. This abnormal behavior of latitudinal distribution of M2 may be caused by the large magnetic declination angle at 50°W ∼ 20°E longitudes. Meanwhile, the longitudinal variation and hemispheric asymmetry of M2 amplitude are different between NH winter (SSW period) and other seasons. The M2 amplitudes were stronger disturbances in the NH and in the American longitudinal sector in NH winter. However, in other seasons, the M2 amplitude was largest in Asian sector, and the M2 amplitude in NH was larger than SH at 0° ∼ 130°E longitudes, which was contrast to these at 0° ∼ 110°W longitudes. These differences of M2 variation between NH winter and other seasons may be related to the differences of the combined effects of the geomagnetic configuration and background conditions of the atmosphere and ionosphere.

Ionospheric behaviors and characteristics in Asian sector during the April 2023 geomagnetic storm with multi-instruments observations

Geomagnetic storms frequently affect satellite navigation, communication and satellite orbits. Monitoring and understanding the ionospheric disturbances and responses to geomagnetic storms are crucial. The detailed ionospheric responses and physical mechanisms to various geomagnetic storms, however, have not yet been extensively studied. In this paper, the ionospheric variation behaviors and features following the April 2023 magnetic storm along the Asian sector are thoroughly studied using multi-instrument observation data, including the Global Navigation Satellite System (GNSS), ionosonde, and other satellites. Large-scale Traveling Ionospheric disturbances (LSTIDs) are observed from BeiDou Geostationary Earth Orbit (GEO) satellites, GPS and GLONASS. LSTIDs traveled with a speed of 760–1300 m/s from high latitude region to low latitude region with a period of about 40 min. The equatorial propagating LSTIDs were generated by coronal mass ejections (CMEs), which occurred in April 2023 with periodic energy input from the auroral area. The poleward LSTIDs are also observed with a velocity of approximately 600–750 m/s and the period is similar. Neutral wind also influenced the characteristics of the ionospheric response. The [O]/[N2] ratio declined during the storm, which led to the formation of the negative storm phases. The largest vertical total electron content (VTEC) is found, and the strengthened region of TEC is mainly centered between ± 20° within geographical latitude. Equatorial Ionospheric Anomaly (EIA) is also observed, which is probably influenced by the electric field. As the time goes on, the peak on the south side of the EIA is disappearing. Meanwhile, the height of the ionospheric maximum electron density rises, and the electron density falls.

Evidence of the potential benefits of digital technology integration in Asian agronomy and forestry: A systematic review

CONTEXTThe agronomy–livestock–forestry nexus is critical as it influences ecosystem services, food production, and land use. Asia, a diverse and technologically dynamic region, faces disparities in agronomy tech adoption. Studies emphasize agronomy and forestry's pivotal role in determining livelihoods in the region. Challenges like rising food demand, land scarcity, climate change, and biodiversity loss require innovative solutions. Digital technologies offer enhanced productivity, sustainability, and resource management opportunities, defining the era of smart agriculture and forestry. OBJECTIVESThis work presents a Systematic Literature Review (SLR), which examines the potential for using digital technology in agronomy and forestry across Asian countries and evaluates evidence of the potential benefits for practitioners and the environment. METHODSThe Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method guided the choice of relevant publications. Of the 375 papers located in Scopus and Web of Science (WoS) databases, only 24 were considered relevant to the research questions. RESULTS AND CONCLUSIONSIn the agronomy and forestry sectors in Asia, the adoption of digital technologies has the potential to contribute toward the promotion of biodiversity, the preservation of ecosystem services, improved labor efficiency, risk reduction, and the promotion of climate change resilience. Geospatial tools, modeling tools, decision support systems, Unmanned Aircraft Systems (UAS), and the Internet of Things (IoT) have emerged as prominent technologies driving these positive outcomes. The study lists evidence from various articles supporting these benefits, although most demonstrate indirect causation. This underscores the need for more direct experiments to establish the broader contribution of digital technologies as well as provide evidence showing farmer uptake and the potential negative impacts of implementation. SIGNIFICANCEThe findings from this study offer a comprehensive view of the potential use of digital technologies for agronomy and forestry in Asia, as well as evidence of their potential benefits. It gives stakeholders valuable information on digital technologies and provides a springboard for future studies regarding the application of digital technology in agronomy, animal husbandry, and forestry.

The Middle and Low Latitude Ion Composition Variations Observed by the DMSP Satellites on 20–31 August 2018

AbstractThe coupling between the ionosphere and plasmasphere is not known well during the quiet and storm times. The topside ionosphere ion composition reflects the exchange between the ionosphere and plasmasphere. We used the DMSP satellite observations to show the changes of the 840 km altitude H+ and O+ ions at ∼3–6 LT in the mid‐ and low‐latitudes on 20–31 August 2018 where a storm occurred on 25 August. The H+ was the main ion at 3–4 LT, and its concentration presented two peaks around 40°N/S magnetic latitudes on 20–24 August. The H+ concentration strongly lessened for more than five days around 40°N/S magnetic latitudes in the recovery phase of the storm on 26–30 August. Further, the enhancement and reduction of the H+ concentration persisted mainly in the Pacific and Asian sectors. The O+ density increased in Northern Hemisphere at 6:36 LT, and the H+ concentration showed the maximum around the magnetic equator during the quiet times, while the H+ concentration still mainly reduced around 40°N/S and stronger at 40°S in the recovery phase. The plasmaspheric total electron content showed a peak around the magnetic equator on 20–24 August, and the peak was weakened or disappeared on 26–30 August. The plasmasphere might be the principal sources for the mid‐latitude H+ enhancement along the geomagnetic field lines during the quite times and the storm‐time suppressed plasmasphere plasma density would weaken the supply of the H+ at 840 km altitude.