The Predictability Limit of Oceanic Mesoscale Eddy Tracks in the South China Sea

Employing the nonlinear local Lyapunov exponent (NLLE) technique, this study assesses the quantitative predictability limit of oceanic mesoscale eddy (OME) tracks utilizing three eddy datasets for both annual and seasonal means. Our findings reveal a discernible predictability limit of approximately 39 days for cyclonic eddies (CEs) and 44 days for anticyclonic eddies (AEs) within the South China Sea (SCS). The predictability limit is related to the OME properties and seasons. The long-lived, large-amplitude, and large-radius OMEs tend to have a higher predictability limit. The predictability limit of AE (CE) tracks is highest in autumn (winter) with 52 (53) days and lowest in spring (summer) with 40 (30) days. The spatial distribution of the predictability limit of OME tracks also has seasonal variations, further finding that the area of higher predictability limits often overlaps with periodic OMEs. Additionally, the predictability limit of periodic OME tracks is about 49 days for both CEs and AEs, which is 5-10 days higher than the mean values. Usually, in the SCS, OMEs characterized by high predictability limit values exhibit more extended and smoother trajectories and often move along the northern slope of the SCS.

Moisture Sources and Their Contributions to Summer Precipitation in the East of Southwest China

Complex topography,special geographical location and sea-land-air interactions lead to high interannual variability of summer precipitation in the east of Southwest China(ESWC).However,the contributions,influencing factors and mechanisms of remote and local evaporation remain to be further investigated.Using clustering analysis and Hybrid Single-Particle Lagrangian Integrated Trajectory version 5 model,we analyze the contributions of remote moisture transport and local evaporation to summer precipitation in the ESWC and their causes.There are mainly five remote moisture channels in the ESWC,namely the Arabian Sea channel,Bay of Bengal channel,western Pacific channel,Northwest channel 1 and Northwest channel 2.Among the five channels,the western Pacific channel has the largest number of trajectories,while the Bay of Bengal channel has the largest contribution rate of specific humidity(33.33%)and moisture flux(33.14%).The amount of regional average precipitation is close to that of the precipitation caused by remote moisture transport,and both are considerably greater than the rainfall amount caused by local evaporation.However,on interannual time scales,precipitation recirculation rates are negatively correlated to regional average precipitation and precipitation caused by remote moisture transport but are consistent with that caused by local evaporation.An apparent"+-+"wave train can be found on the height anomaly field in East Asia,and the sea surface temperature anomalies are positive in the equatorial Middle-East Pacific,the South China Sea,the Bay of Bengal and the Arabian Sea.These phenomena cause southwest-northeast moisture transport with strong updrafts,thereby resulting in more precipitation in the ESWC.

Local Climate Change Induced by Urbanization on a South China Sea Island

The South China Sea is a hotspot for regional climate research.Over the past 40 years,considerable improvement has been made in the development and utilization of the islands in the South China Sea,leading to a substantial change in the land-use of the islands.However,research on the impact of human development on the local climate of these islands is lacking.This study analyzed the characteristics of local climate changes on the islands in the South China Sea based on data from the Yongxing Island Observation Station and ERA5 re-analysis.Furthermore,the influence of urbanization on the local climate of the South China Sea islands was explored in this study.The findings revealed that the 10-year average temperature in Yongxing Island increased by approximately 1.11℃from 1961 to 2020,and the contribution of island development and urbanization to the local warming rate over 60 years was approximately 36.2%.The linear increasing trend of the annual hot days from 1961–2020 was approximately 14.84 days per decade.The diurnal temperature range exhibited an increasing trend of 0.05℃per decade,whereas the number of cold days decreased by 1.06days per decade.The rapid increase in construction on Yongxing Island from 2005 to 2021 led to a decrease in observed surface wind speed by 0.32 m s^(-1)per decade.Consequently,the number of days with strong winds decreased,whereas the number of days with weak winds increased.Additionally,relative humidity exhibited a rapid decline from 2001 to 2016 and then rebounded.The study also found substantial differences between the ERA5 re-analysis and observation data,particularly in wind speed and relative humidity,indicating that the use of re-analysis data for climate resource assessment and climate change evaluation on island areas may not be feasible.

Spatiotemporal Evolution Characteristics of Urban Land Surface Temperature Based on Local Climate Zones in Xi’an Metropolitan,China

Local climate zones(LCZs)are an effective nexus linking internal urban structures to the local climate and have been widely used to study urban thermal environment.However,few studies considered how much the temperature changed due to LCZs transformation and their synergy.This paper quantified the change of urban land surface temperature(LST)in LCZs transformation process by combining the land use transfer matrix with zonal statistics method during 2000–2019 in the Xi’an metropolitan.The results show that,firstly,both LCZs and LST had significant spatiotemporal variations and synchrony.The period when the most LCZs were converted was also the LST rose the fastest,and the spatial growth of the LST coincided with the spatial expansion of the built type LCZs.Secondly,the LST difference between land cover type LCZs and built type LCZs gradually widened.And LST rose more in both built type LCZs transferred in and out.Finally,the Xi’an-Xianyang profile showed that the maximum temperature difference between the peaks and valleys of the LST increased by 4.39℃,indicating that localized high temperature phenomena and fluctuations in the urban thermal environment became more pronounced from 2000 to 2019.

Evolution of Intraseasonal Oscillation over the Tropica lWestern Pacific/South China Sea and Its Effect to the Summer Precipitation in Southern China

In this paper, the evolution of intraseasonal oscillation over the South China Sea and tropical western Pacific area and its effect to the summer rainfall in the southern China are studied based on the ECMWF data and TBB data) analyses. A very low-frequency waves exist in the tropics and play an important role in dominating intraseasonal oscillation and lead to special seasonal variation of intraseasonal oscillation over the South China Sea/tropical western Pacific area. The intraseasonal oscillation (convection) over the South China Sea and tropical western Pacific area is closely related to the summer rainfall (convection) in the southern China. Their relationship seems to be a seesaw feature, and this relationship resulting from the different pattern of convection in those two regions is caused by the differnt type of local meridional circulation.

Evaluating the suitability of different terrains for sustaining human settlements according to the local elevation range in China using the ASTER GDEM

The topographical suitability assessment of human settlements(SAHS) creates a solid foundation for regional population distribution and socio-economic development. Local elevation range(LER) is an important factor that can be used to assess the suitability of different terrains for sustaining human settlements. However, current digital elevation model(DEM)-based LER products suffer from some challenges typically because of their subjectively selected neighborhood scales and coarser spatial resolution. In this study, we initially determined the optimal statistical window and then calculated the appropriate LER with the finer resolution data of the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM(ASTER GDEM) products for China. Then, the appropriate LER was used to evaluate the topographical SAHS and its correlations with the national gridded population distribution(1 km × 1 km) in 2010. The results show that the optimal statistical window for calculating a 1 arc-second(about 30 m) resolution GDEM LER for China can be determined using a 51 × 51 grid unit(width × height) within a rectangular neighborhood, corresponding to an area of about 2.34 km^2. Secondly, the LER values in the southern and western China were greater than those of the north and east, showing a trend which consistently reflects the general spatial features of landforms. Finally, the relationship between GDEM LER and population density was highly correlated with the R^2 value of 0.81. It showed that 85.22% of the Chinese population was located in areas where the LER is lower than 500 m. The topographically suitable area within China decreased from the southeastern coastal zone towards the northwestern inland areas due to transition from plains and basins to plateaus and mountains. The total area of moderate to high suitable level was 423.84 × 10~4 km^2, or 44.15% of the total land area, with 88.17% of the national population. Our study demonstrates the usefulness of appropriate LER in evaluating the topographical SAHS as well as its significant impact on population distribution.

THE CHARACTERISTICS OF AIR-SEA HEAT FLUX EXCHANGE DURING THE GENERATION AND DEVELOPMENT OF LOCAL TYPHOONS OVER THE SOUTH CHINA SEA

A South China Sea(SCS) local TC(SLT) is defined as a tropical cyclone(TC) that forms within the SCS region and can reach the grade of tropical storm(TS) or above. The statistical features of the SLTs from 1985 to 2007 are analyzed first. It is found that over the SCS about 68% of the TCs can develop into TSs. The SLT intensity is relatively weak and associated with its genesis latitude as well as its track. The SLT monthly number presents a seasonal variation with two peaks in May and July to September. Based on the daily heat flux data from the Woods Hole Oceanographic Institution_Objectively Analyzed air-sea Fluxes(WHOI_OAFlux) in the same period, the air-sea exchange during the process of generation and development of the SLT is studied. Results show that the heat fluxes released to the atmosphere increase significantly day by day before cyclogenesis. The ocean to the south to the TC center provides the main energy. Along with the development of SLT, the regions with large heat fluxes spread clockwise to the north of TC, which reflects the energy dispersion property of vortex Rossby waves in the periphery of the TC. Once the SLT forms the heat fluxes are not intensified as much. During the whole process, the net heat, latent heat and sensible heat flux display a similar evolution, while the latent heat flux makes a main contribution to the net heat flux. The maximum air-sea heat exchange always occurs at the left side of the TC moving direction, which may reflect the influence of the SCS summer monsoon on TC structure.

Local perceptions of the conversion of cropland to forestland program in Jiangxi, Shaanxi, and Sichuan, China

Numerous land-use policies have been implemented in China in recent decades for ecological restoration and conservation to reduce environmental disasters and promote environmental sustainability.Many of these policies follow a top-down approach to implementation and as such,emphasize the hierarchical control within government structures.An understanding of local perceptions of land-use policies is important if the disconnect between policy makers and the target population is to be reduced and if program support is to improve.This study aimed to help improve local implementation,attitude toward,and engagement by examining the influence of socio-economic characteristics on the target population’s(local farmers)perception of the conversion of cropland to forestland program(CFPP)land use policy in Jiangxi,Sichuan,and Shaanxi provinces.It uses logistical regression models,with robust aspects of perception including confidence,support,transparency,prospects,fairness,and willingness to participate.Results indicate that social aspects as well as economic aspects are most important in influencing farmers’perceptions towards the CFPP.The farmers who have received technical support,rural male habitants,educated,and non-middle-aged farmers exhibit more positive perceptions of the program and are much more likely to support it,whereas farmers without any technical support or formal education,and female and middle-aged farmers are less likely to support the program.Importantly,this study also reveals the differences in responses,experiences and perceptions of the farmers living across different provinces.These empirical results provide insight into the influence of socio-economic characteristics on the perception of farmers towards land-use policies,which has important implications for designing targeted policy instruments and increasing farmer support for these policies.This knowledge can be harnessed and further evaluated in future research to improve citizen engagement,support,and understanding in order to help ecological restoration and conservation objectives be more effectively achieved.

A Discussion for the Protection of the Environnement in the Law of Planification in China

This article aims to answer the question that if the law of planification of China,really takes account of the objectives of environmental protection.The answer is based on,first of all,the reform of system of land ownership(direct link of the development of urbanization).This article cracks the problem by two approaches:the state and collective property right.The first part of the analysis is macro-perspective,i.e.,the course of land reform and the land users.In general,the state remains the sole owner of all the land and delegates the local governments to manage the use of land in China.However,the high interest undermines their roles,and degradation of environment in the process of urbanization continues.Based on this observation,we analyzed their administration,i.e.,who are the actors and how the powers are shared.The lack of transparency and independence is in its structure,i.e.,they have ambitions to have a good protection but the conflict appears frequently.In the further part,micro-vision was employed.We focused on the regulations of planification,procedures and formalities that is deeply involved.In fact,we find that the volume of law was expanded and a need of consolidation is urgent for the coherence,accessibility and understanding of law.Then it follows the analysis of two typical procedures:the procedure of environmental assessment as well as participation.These procedures are the practical implementation of the consideration of the environment.The fact is that rapid urbanization resulted in a reconfiguration of the urban space,and the appearance of a variety of interests.The degradation of environment,coupled with the importance of urbanization has become a challenge to governance.People realized more and more issues related to housing,welfare and citizenship.This forces the government to change their policies and acts.From different points of views-historical,political,administrative,legal and social-this research determines how a better environmental protection can play in law of planification.The reforms are envisaged,and there are still problems:the harmonization and consistency of the regulations,the clarity of the law for his efficiency and law security,the improvement of the process.Contrary to what is received,the government has intention to solve this question,as demonstrated by his consistency to innovation and reform in the field.At the present,planification,rather than a method of protection,works for the growth of the economy.Due to the lack of effective regulation,the real consideration of environment is still very limited.

Impact of Wetland Change on Local Climate in Semi-arid Zone of Northeast China

Wetlands are sensitive to climate change, in the same time, wetlands can influence climate. This study analyzed the spatio-temporal characteristics of wetland change in the semi-arid zone of Northeast China from 1985 to 2010, and investigated the impact of large area of wetland change on local climate. Results showed that the total area of wetlands was on a rise in the study area. Although natural wetlands(marshes, riparians and lakes) decreased, constructed wetlands(rice fields) increased significantly, and the highest increase rate in many places exceeded 30%. Anthropogenic activities are major driving factors for wetland change. Wetland change produced an impact on local climate, mainly on maximum temperature and precipitation during the period of May–September. The increase(or decrease) of wetland area could reduce(or increase) the increment of maximum temperature and the decrement of precipitation. The changes in both maximum temperature and precipitation corresponded with wetland change in spatial distribution. Wetland change played a more important role in moderating local climate compared to the contribution of woodland and grassland changes in the study area. Cold-humid effect of wetlands was main way to moderating local climate as well as alleviating climatic warming and drying in the study area, and heterogeneity of underlying surface broadened the cold-humid effect of wetlands.

The South China Sea throughflow: linkage with local monsoon system and impact on upper thermal structure of the ocean

The tendency of South China Sea throughflow (SCSTF) variation associated with the local monsoon system, and its impact on upper-layer thermal structure, are studied using the Simple Ocean Data Assimilation (SODA) dataset, combined with Ishii reanalysis data. Luzon Strait Transport (LST) is measured and used as an index for studying the SCSTF variation. Results show that LST had an increasing tendency over the last 50 years, mainly in summer and fall. The increasing tendency was 0.017 1 Sv/a in summer and 0.027 4 Sv/a in fall, as estimated by SODA, and 0.018 0Sv/a in summer and 0.018 9 Sv/a in fall, as estimated by "Island Rule" theory. LST increased by 0.53Sv in JJA (June-July-August) and 0.98Sv in SON (September-October-November) after climate shift, as inferred by SODA data. The average LST anomaly in JJA and SON is strongly related to the local monsoon system, especially to variability of the meridional wind stress anomaly after application of a 3-year running mean, with correlation coefficients 0.57 and 0.51, respectively. In addition to the basin-scale wind forcing, the local northeasterly wind stress anomaly in the SCS can push Pacific water entering the SCS more readily in JJA and SON after climate shift, and an SCSTF-associated cooling effect may favor subsurface cooling more frequently after climate shift.

Localization Reform of Carbon Emissions Trading Mechanism in China

Based on the practical experiences of Guangdong carbon emissions trading pilot, the key issues such as cap setting, allowance alloca- tion, system defects, regulatory integration and MRV mechanisms were analyzed in this paper from the localization perspective. A number of solu- tions and policy recommendations were also proposed in this study in order to solve these barriers.

Ecological Marxism and Reconstruction of China's Ecological Values

The core and connotation of ecological Marxism was analyzed. The reality significance of reconstructing ecological value in China was discussed. Ways to construct ecological value were proposed in the end. Correct analysis and understanding of ecological Marxist theory has a pos- itive and far-reaching significance for the whole society to establish the correct ecological values, to deepen scientific understanding on the relation- ship between man and nature, and to build a harmonious socialist society.

A Brief Study on the Formation and Features of the Development Path of Human Rights in China

General Secretary Xi Jinping delivered an important speech at a group study session of the Political Bureau of the Communist Party of China Central Committee on February 25,2022,stressing the importance of"unswervingly following the development path of Human Rights in China."After years of theoretical exploration and practical experience in human rights,the path has been blazed.It has been taken by adhering unswervingly to the strong leadership of the CPC,respecting the principal position of the people,practicing the people-centered development concept,proceeding from China s reality and the requirements of the people,combining the principle of universality of human rights with China's reality,strengthening the system and the rule of law protection of human rights,and actively participating in global governance on human rights.Only by unswervingly following the development path of human rights in China can the cause of human rights in China achieve better and faster development.

Administrative Urbanization and City-making in Post-reform China: A Case Study of Ordos City, Inner Mongolia

In post-reform China, local governments, instead of the central state, have become major promoters of urbanization. Differing from the existing literature based on Western theories, this article argues that a localized perspective, ‘administrative urbanization', can provide a contextual explanation for the mechanism of urbanization in the reform era. The case study of Ordos indicates that new town construction, especially in the inland area, has become the main strategy for investment attraction and economic development. The local government has played a dominant role in this construction through a series of administrative measures, including avoidance of central state regulations, land leasing, high standard infrastructure construction, relocation policies and industrial attraction. This article also explores the issue of unsustainability in the new town, and identifies that underdeveloped industrialization, slow population agglomeration and real estate bubbles are primary threats to the sustainability of administrative urbanization.

Assimilating satellite SST/SSH and in-situ T/S profiles with the Localized Weighted Ensemble Kalman Filter

The Localized Weighted Ensemble Kalman Filter(LWEnKF)is a new nonlinear/non-Gaussian data assimilation(DA)method that can effectively alleviate the filter degradation problem faced by particle filtering,and it has great prospects for applications in geophysical models.In terms of operational applications,along-track sea surface height(AT-SSH),swath sea surface temperature(S-SST)and in-situ temperature and salinity(T/S)profiles are assimilated using the LWEnKF in the northern South China Sea(SCS).To adapt to the vertical S-coordinates of the Regional Ocean Modelling System(ROMS),a vertical localization radius function is designed for T/S profiles assimilation using the LWEnKF.The results show that the LWEnKF outperforms the local particle filter(LPF)due to the introduction of the Ensemble Kalman Filter(EnKF)as a proposal density;the RMSEs of SSH and SST from the LWEnKF are comparable to the EnKF,but the RMSEs of T/S profiles reduce significantly by approximately 55%for the T profile and 35%for the S profile(relative to the EnKF).As a result,the LWEnKF makes more reasonable predictions of the internal ocean temperature field.In addition,the three-dimensional structures of nonlinear mesoscale eddies are better characterized when using the LWEnKF.

ANALYSIS ON WAVELET POWER SPECTRUM OF WARM AND COLD EVENTS IN THE NIO REGIONS

We statistically analyze the tropical typhoon forming in the South China Sea and use TC (Tropical Cyclone) for short in the following) by typhoon yearbook. The typhoon quantity is very different in different months and years. TC appears in all months except March, and the most TC quantity in a year is 11, the least is 1 and 6.2 on average. The most TC quantity in a month is 5 and the least is 0. TC lands most in August and no TC lands on Chinese continent from December to the following April. The primary landing area is between Shantou and Hainan Island. The sustaining period of TC is usually between 4 days to 7days, and the longest is 19 days. Only 15% of the TC forming in the South China Sea can intensify to typhoon, and they all form in the ocean area deeper than 150m. The South China Sea is the ocean area over which the TC occurs frequently.

Analysis of the Relationship between Vertical Distribution of Four Automatic Stations and Local Precipitation in Taihang Mountain of Linzhou

[ Objective] The reseamh aimed to analyze the relationship between vertical distribution of four automatic stations and local precipitation in Taihang Mountain of Linzhou. [ Method] Using mesoscale detection and statistical data of the automatic stations in Henan, the geographical distribution of the precipitation affected by underlying surface in mountainous area of Linzhou was analyzed. [ Result] Surface mesoscale wind field convergence line formed by thermal action of inhomogeneous underlying surface and mountainous terrain and upward movement played the strengthening role to the low-level jet. They affected formation and development of strong convective weather. The geographic distribution of precipitation in mountainous area was highly affected by the terrain, and rainfall, precipitation days and intensity in mountainous area were significantly greater than that in the surrounding hills region. In particular, rainfall on the windward slope significantly increased, and rainfall increased as mountain height within a certain height. [ Conclusion] Hourly ground data analysis at automatic stations had very good forecast indication role in formation, development and dissipation of heavy rain in mountainous areas.

Irregular Information of the Rainstorm in a Continuous Rainy Weather

[Objective] The research aimed to analyze irregular information of the local rainstorm process (during 5-6 September,2009) in autumn continuous rainy weather in north Shaanxi. [Method] Based on V-3θ chart, routine observation data provided by Micaps system, satellite cloud chart and data at 100 automatic meteorological stations of Shaanxi, for rainstorm process in autumn continuous rainy weather in north Shaanxi during 4-10 September, 2009, by using structure analysis method, irregular information in local rainstorm weather was analyzed. [Result] In whole precipitation process, atmospheric structure in rainstorm zone presented obvious evolution process. Before precipitation, typical atmospheric structure information of the sudden convective weather appeared. Obvious ultra-low temperature structure appeared at 200 hPa, and consistent clockwise rotation flow was at vertical wind field. Meanwhile, water vapor was sufficient, and unstable energy existed at low layer. Structure characteristic of the convective strong precipitation appeared by advancing for 12h. As precipitation weakened, unstable energy was released, and ultra-low temperature disappeared. [Conclusion] The research provided some thoughts for the forecast of such weather process.