THE PROGRAM OF GLOBAL CHARACTER RESEARCH OF SOLAR TERRESTRIAL SYSTEM IN THE 22TH SOLAR CYCLE—Forward of the Proceedings

The expert group for strategic study of promoting coherence research on astronomy,space science and earth science organized in the summer of 1985 by the planning Bureauof CAS presented a proposal on the global character research of solar-terrestrial systemin 1986. The proposal was extensively supported by the scientific workers in the fields ofsolar physics, space physics and geo-sciences, and also the persons in HQ of CAS. Pro-fessor Zhou Guang-zhao, the president of CAS, suggested emphasizing the coordinatedstudy in the period of the solar maximum year. The application for one of

RESEARCH ON THE GLOBAL CHARACTER OF THESOLAR-TERRESTRIAL SYSTEM FROM THE MAJOR SOLAR EVENTS IN MARCH AND AUGUST, 1989

The great sunspot group which appeared in March, 1989, has been the largest one inrecent four decades. There occurred also the extraordinary solar activities and majorgeophysical effects associated with this region. A lot of solar-geophysical data have beenacquired througy the joint observations in China. A workshop on the observations andanalyses of the major solar-terrestrial events in March and August, 1989, was held

Study on the vertical deformations induced by terrestrial water storage changes in Huang-Huai-Hai river basin

Terrestrial water storage(TWs)variations are associated with water mass movements,which may cause the deformation displacements of the Global Navigation Satellite System(GNSS)stations.This study investigates the spatio-temporal Tws variations and addresses the relationship between deformation variations observed in the Huang-Huai-Hai River Basin(HHHRB)and local hydrological features.Results indicate that the vertical velocities at the GNSS stations induced by TWS changes are relatively small,and the impacts of the terrestrial water storage changes are mainly reflected in the changes of seasonal characteristics.Although there is a downward TWS trend from 2011 to 2022 in most HHHRB areas,velocities from the vertical displacements of both Gravity Recovery and Climate Experiment(GRACE)and GRACE Follow-On(GFO)and the GNSS reflect that the HHHRB is undergoing an uplift process,while the magnitude of the GRACE/GFO derived velocities is much smaller than that of the GNSS solutions.Common hydrological deformations estimated from GRACE/GFO and GNSS measurements reveal that the TWS-derived displacements can explain 54.5%of the GNSS seasonal variations,with the phases of terrestrial water storage advancing by about one month relative to GNss common signal phases.Moreover,the decrease of the groundwater storage in the HHHRB has been accelerating since 2008.After reaching its lowest level around mid-2020,it began to rise rapidly,which might be closely related to the implementation of the South-North Water Transfer Central Project.

Tree species identity and interaction determine vertical forest structure in young planted forests measured by terrestrial laser scanning

Vertical forest structure is closely linked to multiple ecosystem characteristics,such as biodiversity,habitat,and productivity.Mixing tree species in planted forests has the potential to create diverse vertical forest structures due to the different physiological and morphological traits of the composing tree species.However,the relative importance of species richness,species identity and species interactions for the variation in vertical forest structure remains unclear,mainly because traditional forest inventories do not observe vertical stand structure in detail.Terrestrial laser scanning(TLS),however,allows to study vertical forest structure in an unprecedented way.Therefore,we used TLS single scan data from 126 plots across three experimental planted forests of a largescale tree diversity experiment in Belgium to study the drivers of vertical forest structure.These plots were 9–11years old young pure and mixed forests,characterized by four levels of tree species richness ranging from monocultures to four-species mixtures,across twenty composition levels.We generated vertical plant profiles from the TLS data and derived six stand structural variables.Linear mixed models were used to test the effect of species richness on structural variables.Employing a hierarchical diversity interaction modelling framework,we further assessed species identity effect and various species interaction effects on the six stand structural variables.Our results showed that species richness did not significantly influence most of the stand structure variables,except for canopy height and foliage height diversity.Species identity on the other hand exhibited a significant impact on vertical forest structure across all sites.Species interaction effects were observed to be site-dependent due to varying site conditions and species pools,and rapidly growing tree species tend to dominate these interactions.Overall,our results highlighted the importance of considering both species identity and interaction effects in choosing suitable species combinations for forest management practices aimed at enhancing vertical forest structure.

Assessment of natural and anthropogenic impacts on terrestrial water storage in the Loess Plateau based on different types of GRACE/GRACE-FO solutions

Changes in water resource storage are inevitable due to climate change and human activities,thus understanding alterations in water storage within a specific region is imperative for the planning and management of water resources.Data from the Gravity Recovery and Climate Experiment(GRACE)satellite mission are extensively employed to analyze large-scale total terrestrial water storage anomalies(TWSA).In this study,we derived a more reliable TWSA using different types of GRACE gravity models,which served as the basis for evaluating spatial and temporal variations in total terrestrial water storage and its hydrological components(soil moisture and groundwater)across the Loess Plateau.Additionally,we analyzed the impact of natural and anthropogenic influences on water storage in the Loess Plateau,categorizing them into primary and secondary influences,utilizing data on climate and human activities.The findings revealed a declining trend in the overall TWSA of the Loess Plateau,with a rate of decrease at-0.65±0.05 cm/yr from 2003 to 2020(P<0.01).As the direct factors affecting TWSA,soil moisture dominated the change of TWSA before 2009,and groundwater dominated the change of TWSA after 2009.Spatially,there was variability in the changes of TWSA in the Loess Plateau.More in-depth studies showed that soil moisture changes in the study area were primarily driven by evapotranspiration and temperature,with precipitation and vegetation cover status playing a secondary role.Human activities had a secondary effect on soil moisture in some sub-regions.Population change and agricultural development were major factors in altering groundwater storage in the study area.Other than that,groundwater was influenced by natural factors to a limited extent.These findings provided valuable insights for local governments to implement proactive water management policies.

Impacts of artificial dams on terrestrial water storage changes and the Earth's elastic load response during 1950-2016: A case study of medium and large reservoirs in Chinese mainland

The construction of dams for intercepting and storing water has altered surface water distributions, landsea water exchanges, and the load response of the solid Earth. The lack of accurate estimation of reservoir properties through the land surface and hydrological models can lead to water storage simulation and extraction errors. This impact is particularly evident in many artificial reservoirs in China. The study aims to comprehensively assess the spatiotemporal distribution and trends of water storage in medium and large reservoirs(MLRs) in Chinese mainland during 1950-2016, and to investigate the gravity,displacement, and strain effects induced by the reservoir mass concentration using the load elasticity theory. In addition, the impoundment contributions of MLRs to the relative sea level changes were assessed using a sea-level equation. The results show impoundment increases in the MLRs during1950-2016, particularly in the Yangtze River(Changjiang) and southern basins, causing significant elastic load effects in the surrounding areas of the reservoirs and increasing the relative sea level in China's offshore. However, long-term groundwater estimation trends are overestimated and underestimated in the Yangtze River and southwestern basins, respectively, due to the neglect of the MLRs impacts or the uncertainty of the hydrological model's output(e.g., soil moisture, etc.). The construction of MLRs may reduce the water mass input from land to the ocean, thus slowing global sea level rise. The results of the impact of human activities on the regional water cycle provide important references and data support for improving the integration of hydrological models, evaluating Earth's viscoelastic responses under longterm reservoir storage, enhancing in-situ and satellite geodetic measurements, and identifying the main factors driving sea level changes.

Energy-Efficient Traffic Offloading for RSMA-Based Hybrid Satellite Terrestrial Networks with Deep Reinforcement Learning

As the demands of massive connections and vast coverage rapidly grow in the next wireless communication networks, rate splitting multiple access(RSMA) is considered to be the new promising access scheme since it can provide higher efficiency with limited spectrum resources. In this paper, combining spectrum splitting with rate splitting, we propose to allocate resources with traffic offloading in hybrid satellite terrestrial networks. A novel deep reinforcement learning method is adopted to solve this challenging non-convex problem. However, the neverending learning process could prohibit its practical implementation. Therefore, we introduce the switch mechanism to avoid unnecessary learning. Additionally, the QoS constraint in the scheme can rule out unsuccessful transmission. The simulation results validates the energy efficiency performance and the convergence speed of the proposed algorithm.

Changes of Terrestrial Water Storage in the Yellow River Basin Under Global Warming

The increasing temperature in the Yellow River Basin has led to a rapid rise in the melting level height,at a rate of 5.98 m yr^(-1)during the cold season,which further contributes to the transition from snowfall to rainfall patterns.Between 1979 and 2020,there has been a decrease in snowfall in the Yellow River Basin at a rate of-3.03 mm dec^(-1),while rainfall has been increasing at a rate of 1.00 mm dec^(-1).Consequently,the snowfall-to-rainfall ratio(SRR)has decreased.Snowfall directly replenishes terrestrial water storage(TWS)in solid form until it melts,while rainfall is rapidly lost through runoff and evaporation,in addition to infiltrating underground or remaining on the surface.Therefore,the decreasing SRR accelerates the depletion of water resources.According to the surface water balance equation,the reduction in precipitation and runoff,along with an increase in evaporation,results in a decrease in TWS during the cold season within the Yellow River Basin.In addition to climate change,human activities,considering the region's dense population and extensive agricultural land,also accelerate the decline of TWS.Notably,irrigation accounts for the largest proportion of water withdrawals in the Yellow River Basin(71.8%)and primarily occurs during the warm season(especially from June to August).The impact of human activities and climate change on the water cycle requires further in-depth research.

System Integration of Terrestrial Mobile Communication and Satellite Communication——The Trends, Challenges and Key Technologies in B5G and 6G

Mobile communication standards have been developed into a new era of B5G and 6G.In recent years,low earth orbit(LEO)satellites and space Internet have become hot topics.The integrated satellite and terrestrial systems have been widely discussed by industries and academics,and even are expected to be applied in those huge constellations in construction.This paper points out the trends of two stages towards system integration of the terrestrial mobile communication and the satellite communications:to be compatible with 5G,and to be integrated within 6G.Based on analysis of the challenges of both stages,key technologies are thereafter analyzed in detail,covering both air interface currently discussed in 3GPP for B5G and also novel network architecture and related transmission technologies toward future 6G.

Summary of Recent Climate Change Studies on the Carbon and Nitrogen Cycles in the Terrestrial Ecosystem and Ocean in China

This article reviews recent advances over the past and their relationship to climate change in China. The was 0.19-0.26 Pg C yr-1 for the 1980s and 1990s. 4 years in the study of the carbon-nitrogen cycling net carbon sink in the Chinese terrestrial ecosystem Both natural wetlands and the rice-paddy regions emitted 1.76 Tg and 6.62 Tg of CH4 per year for the periods 1995 2004 and 2005 2009, respectively. China emitted -1.1 Tg N20-N yr-1 to the atmosphere in 2004. Land soil contained -8.3 Pg N. The excess nitrogen stored in farmland of the Yangtze River basin reached 1.51 Tg N and 2.67 Tg N in 1980 and 1990, respectively. The outer Yangtze Estuary served as a moderate or significant sink of atmospheric CO2 except in autumn. Phytoplankton could take up carbon at a rate of 6.4 ×1011 kg yr-1 in the China Sea. The global ocean absorbed anthropogenic CO2 at the rates of 1.64 and 1.73 Pg C yr-1 for two sinmlations in the 1990s. Land net ecosystem production in China would increase until the mid-21st century then would decrease gradually under future climate change scenarios. This research should be strengthened in the future, including collection of more observation data, measurement of the soil organic carbon （SOC） loss and sequestration, evaluation of changes in SOC in deep soil layers, and the impacts of grassland management, carbon-nitrogen coupled effects, and development and improvement of various component models and of the coupled carbon cycle-climate model.

Evaluation and mapping of relative sensitivity of the terrestrial ecosystems to acidic deposition in Fujian

Based on the semi-quantitative approach, four environmental factors of sites (i.e. bedrock lithology, soil type, land use, and rainfall) were categorized, weighted and combined to determine and assess the relative sensitivity of the terrestrial ecosystems to acidic deposition in Fujian Province. Then the factors have been digitized and combined to assign an overall value for each mesh square (16.77 km×18.39 km) by using the geographic information system (GIS) The results indicated that the most sensitive area in Fujian was mainly located in the southeast, and the least: ensitive area was distributed sporadically in the east along the coast. Due to slow weathering rate of siliceous rocks, acid to weakly acid reactions of the soils, along with the greater percent of coniferous forests, more than 80 percent of the total area exhibits higher sensitivity classes (4–7).

A Study on Development of a Hybrid Aerial/Terrestrial Robot System for Avoiding Ground Obstacles by Flight

To date, many studies related to robots have been performed around the world. Many of these studies have assumed operation at locations where entry is difficult, such as disaster sites, and have focused on various terrestrial robots, such as snake-like, humanoid, spider-type, and wheeled units. Another area of active research in recent years has been aerial robots with small helicopters for operation indoors and outdoors. However,less research has been performed on robots that operate both on the ground and in the air. Accordingly, in this paper, we propose a hybrid aerial/terrestrial robot system. The proposed robot system was developed by equipping a quadcopter with a mechanism for ground movement. It does not use power dedicated to ground movement, and instead uses the flight mechanism of the quadcopter to achieve ground movement as well. Furthermore, we addressed the issue of obstacle avoidance as part of studies on autonomous control. Thus, we found that autonomous control of ground movement and flight was possible for the hybrid aerial/terrestrial robot system, as was autonomous obstacle avoidance by flight when an obstacle appeared during ground movement.

Intelligent Interference Management and Secure Communications for Satellite-Terrestrial Integrated Systems

Satellite-terrestrial integrated(STI)systems represent the right solution to meet complex requirements of several services and sharing of the limited spectral resources between satellite systems and terrestrial ones must be considered to optimize performance.Network architectures and traffic demand are different for the satellite component and for the terrestrial 5G/6G one,so that the requirements of spectral resources for satellite and terrestrial systems are expected to vary dynamically in a significant range.

Research Advances in Net Primary Productivity of Terrestrial Ecosystem

The net primary productivity of vegetation reflects the total amount of carbon fixed by plants through photosynthesis each year. The study of vegetation net primary productivity is one of the core contents of global change and terrestrial ecosystems. This article reviews the current research status of net primary productivity of terrestrial vegetation, and comprehensively analyzes the advantages and disadvantages of three types of productivity estimation models, climate relative models, biogeochemical models, and light energy utilization models. The light energy utilization models have become the mainstream method for estimating vegetation net primary productivity because they can directly use remote sensing data. However, there are still many deficiencies in the estimation of vegetation net primary productivity, which need to be further improved and tested.

Automatic identification of rock discontinuity and stability analysis of tunnel rock blocks using terrestrial laser scanning

Local geometric information and discontinuity features are key aspects of the analysis of the evolution and failure mechanisms of unstable rock blocks in rock tunnels.This study demonstrates the integration of terrestrial laser scanning(TLS)with distinct element method for rock mass characterization and stability analysis in tunnels.TLS records detailed geometric information of the surrounding rock mass by scanning and collecting the positions of millions of rock surface points without contact.By conducting a fuzzy K-means method,a discontinuity automatic identification algorithm was developed,and a method for obtaining the geometric parameters of discontinuities was proposed.This method permits the user to visually identify each discontinuity and acquire its spatial distribution features(e.g.occurrences,spac-ings,trace lengths)in great detail.Compared with hand mapping in conventional geotechnical surveys,the geometric information of discontinuities obtained by this approach is more accurate and the iden-tification is more efficient.Then,a discrete fracture network with the same statistical characteristics as the actual discontinuities was generated with the distinct element method,and a representative nu-merical model of the jointed surrounding rock mass was established.By means of numerical simulation,potential unstable rock blocks were assessed,and failure mechanisms were analyzed.This method was applied to detection and assessment of unstable rock blocks in the spillway and sand flushing tunnel of the Hongshiyan hydropower project after a collapse.The results show that the noncontact detection of blocks was more labor-saving with lower safety risks compared with manual surveys,and the stability assessment was more reliable since the numerical model built by this method was more consistent with the distribution characteristics of actual joints.This study can provide a reference for geological survey and unstable rock block hazard mitigation in tunnels subjected to complex geology and active rockfalls.

Analysis and Optimization on Partition-Based Caching and Delivery in Satellite-Terrestrial Edge Computing Networks

As a viable component of 6G wireless communication architecture,satellite-terrestrial networks support efficient file delivery by leveraging the innate broadcast ability of satellite and the enhanced powerful file transmission approaches of multi-tier terrestrial networks.In the paper,we introduce edge computing technology into the satellite-terrestrial network and propose a partition-based cache and delivery strategy to make full use of the integrated resources and reducing the backhaul load.Focusing on the interference effect from varied nodes in different geographical distances,we derive the file successful transmission probability of the typical user and by utilizing the tool of stochastic geometry.Considering the constraint of nodes cache space and file sets parameters,we propose a near-optimal partition-based cache and delivery strategy by optimizing the asymptotic successful transmission probability of the typical user.The complex nonlinear programming problem is settled by jointly utilizing standard particle-based swarm optimization(PSO)method and greedy based multiple knapsack choice problem(MKCP)optimization method.Numerical results show that compared with the terrestrial only cache strategy,Ground Popular Strategy,Satellite Popular Strategy,and Independent and identically distributed popularity strategy,the performance of the proposed scheme improve by 30.5%,9.3%,12.5%and 13.7%.

Effects of atmospheric mercury pollution on terrestrial ecosystem in Chongqing, China

The results from investigations indicated that mercury pollution in terrestrial ecosystem was serious due to the anthropogenic mercury emission growing in Chongqing, China. The concentration of atmospheric mercury in Chongqing was 34.4±2.7 ng/m\+3 with the range of 9.2—101.5. The accumulation of mercury in surface soil was increasing with time. The mercury content of some agricultural products have exceeded the food health standard value, especially near the mercury emission sources. The mercury accumulation in soil plant system was affected by atmospheric mercury and a positive correlation between them was found. Volatilization of mercury was the most important processes with which soil mercury joined the global mercury recycling.

Fate of BHC in the terrestrial ecosystem

The fate of BHC in the terrestrial ecosystem was investigated under both laboratory and field conditions. The uptake, accumulation and degradation of BHC in earthworms and corn plants were studied. Earthworms could absorb and accumulate BHC residues from soil. Statistically, significant correlation existed between the amounts of BHC in soil and in earthworms. Different species of earthworms appeared to concentrate BHC in their bodies to different extents. In a terrestrial ecosystem, the uptake, accumulation of BHC residues by soil animals and plants had an effect on each other.

Experimental Simulation Study of the Dominant Enrichment Area of Terrestrial Organic Matter in the Shallow-Delta Sedimentary System of the Yacheng Formation in the Qiongdongnan Basin

Shallow-delta sedimentary systems receive both terrestrial and marine organic matter. As oil and gas exploration activities determine that the source rocks of the deep-water area of the Qiongdongnan Basin, northern South China Sea, are generally rich in and even dominated by terrestrial organic matter, this has led many researchers to examine the rules governing terrestrial organic matter enrichment in shallow-delta sea sedimentary systems. However, the deep burial of source rocks in deep-water areas and the relatively small amount of drilling undertaken have greatly restricted the study of these rules. In this study, the ‘forward modeling' research method was used to observe and analyze the deposition and preservation of terrestrial organic matter through flume experiments, where the depositional results were carefully depicted and sampled. The total organic carbon content of selected samples was measured and when combined with qualitative observations and quantitative comparison results, the dominant enrichment areas of terrestrial organic matter were identified. The experimental results show that the overbank parts of the delta front, the dune countercurrent surface, the low-lying parts, the delta front slope area and the shallow-prodelta sea area are where terrestrial organic matter is predominantly enriched. This provides an important basis and guidance for the prediction of the development areas of marine source rocks with terrestrial input in the deep-water areas of the Qiongdongnan Basin.

Human impacts on the terrestrial ecosystem of Fildes Peninsula of King George Island, Antarctica

Antarctic environment has valuable baseline information for understanding the global change. The objectives of this study were to investigate the impacts of human activities on Antarctic terrestrial ecosystem. Based on the investigation results and the sampling analysis of the environment of Fildes Peninsula, King George Island, Antarctica, it was shown that there are some artificial radioactive elements—? ? 137 Cs in Antarctic environment: the radioactivity of 137 Cs in the surface soil, the surface moss, the fruticose lichen and the crustaceous lichen are 6 00—14 80, 25 07, 29 04 and 58 07 Bq/kg separately; i.e. the sequence of 137 Cs specific activity is as follows: crustaceous lichen>fruticose lichen>surface moss>surface soil, which demonstrates that the crustaceous lichen is one of the most sensitive monitor ways for the effect of the long term diffusion of 137 Cs. The impacts of the scientific research activities on the partial ecosystem of Fildes Peninsula include: the changes of the landscape and the soil material have made a strong freezing thawing process, which decreases the stability of the ground surface, causes the degradation of the vegetation in the some small areas; some small lakes, runoff and lichens in middle areas of Fildes Peninsula have been affected by the wastes of the stations, in the surrounding areas of the expedition stations, the concentration of Cr, Cu, Ni, Pb and Zn in the lichen and the water are higher than that of the contrasting area. Fildes Peninsula is one of the most crowded areas of expedition stations, at some extent, the environment and terrestrial ecosystem have been affected by the human activities. The conservation of the environment and ecosystem should be an important aspect of Antarctic environmental sciences.