Northeastern Area Research Articles

A trial application of particle-induced X-ray emission analysis to microplastic samples collected from the seashore

Here, we apply 20 MeV particle-induced X-ray emission (PIXE) to elemental analysis of microplastic samples with a diameter of approximately 2 mm, collected from the seashores of the northeastern area of Honshu in Japan. The samples were in a grain form with unwanted elements adhering to their surfaces. The PIXE measurements were conducted in a helium atmosphere. For normalization, the number of K X-rays of the residual gas argon was used instead of the directly measured beam irradiation, and the number of continuous X-rays in the PIXE spectrum was used instead of the mass of each sample. Thirteen elements were identified on the microplastics, among which were toxic chromium and lead. Thus, PIXE analysis is useful for analyzing microplastic samples.

Potential biomass and distribution of octopus in the eastern part of the Campeche Bank (Yucatán, Mexico)

The octopus fishery on the Campeche Bank (Yucatán, Mexico) is considered the third largest in the world. In Yucatán, two fleets target this resource: an artisanal fleet and a semi-industrial fleet. The artisanal fleet only catches Octopus maya, while the semi-industrial fleet catches two species, O. Maya and O. “vulgaris” Type II, because it operates at deeper waters ( > 30 m). Since there is no information on the abundance of O. “vulgaris” Type II, management is based only on O. Maya. In order to generate information about the abundance of this species, four fishing research cruises were carried out in the northeastern area of the continental shelf off the Yucatán Peninsula. Four methods (a stratified random method, a swept area, geostatistics and a weighted swept area) were applied and compared to determine the instantaneous abundance and biomass of both species in the study area. The lowest potential biomass was calculated with the geostatistical method, with values between 18.5% and 36.7% lower than the other three methods. O. “vulgaris” Type II showed the lowest biomass (37.8±3.36 t) during May and July and the highest (189.56±11.6 t) in December. Our findings revealed that the total abun­dance of both species was similar in the study area, with a geographic overlap whose amplitude changed throughout the year according to the geographic position: O. Maya dominated at approximately 88°W, while O. “vulgaris” Type II dominated towards the southeast at 87°W.

Spatial-temporal patterns and characteristics of ecological function between 2009 and 2015 in China

Abstract Ecological function reflects the ability of the land to provide ecological goods to support high-quality human production and life. The evaluation of the county-level ecological function across the whole nation is crucial for sustainable land management, which has not been implemented effectively in China. In this study, we proposed a unified system for the assessment of ecological function that would be comparable at the county level, and we applied the system to evaluate the ecological function of 2850 counties across China based on multi-source data. We also examined the spatiotemporal changes in ecological function from 2009 to 2015 using standard deviational ellipses and coefficients of variation. The results showed that the number of counties with high levels of ecological function in China decreased by 8.13% from 2009 to 2012 and then increased by 0.6% from 2012 to 2015. The spatial pattern of the degradation of ecological function shifted from the east-west direction to the southwest-northeast direction and became centralized in the Central Plains area of China. The regional imbalance in ecological function followed the order from high to low of the central, western, northeastern, and eastern areas of China. Targeted policies were proposed to control the degradation of the ecological function in the four regions in China.

Spatiotemporal Evaluation of Socio-Ecological-Economic System Vulnerability: A County-Level Analysis of Chongqing, China

The research on vulnerability can provide insights into social, economic, and ecological risks. Therefore, the objective of this work was to measure the degree of socio-ecological-economic system (SEES) vulnerability in Chongqing, one of the regions with the high constraint of natural conditions and human activity in the southwest of China. For this, by using three criteria and 40 indices based on the exposure-sensitive-adaptive capacity (ESC) model, an index system was designed. The entropy method was used to determine the weight of the indices. Furthermore, the composite index model and coefficient of variation were applied to evaluate the spatiotemporal characteristics of SEES vulnerability in the study area at the county level. The results showed that the average vulnerability index of SEES from 2005 to 2010 in Chongqing was 0.5735. The development pressure was high, and the ability to resist disturbance from external risks was low. Regional sustainable development was facing challenges. Spatial distribution of SEES vulnerability of Chongqing varied from high (moderately vulnerable or worse) in the western counties to low (mildly vulnerable) in the northeastern and southeastern areas with better ecological bases. The general vulnerability of the ecological and economic subsystems continues to decrease. However, the vulnerability of the social subsystem tended to initially decrease and then increase. Overall, the differences in the pattern of SEES vulnerability of the counties declined. Moreover, economic and social development tended to balance. This study is helpful to understand the overall trend and characteristics of vulnerability change and provides theoretical methods and reference opinions to support regional sustainable development.

RICERCHE STORICO-ARCHEOLOGICHE DELL’UNIVERSITÀ CATTOLICA DI MILANO SUL DELTA DELL’INDO (2010-2018)

RICERCHE STORICO-ARCHEOLOGICHE DELL’UNIVERSITÀ CATTOLICA DI MILANO SUL DELTA DELL’INDO (2010-2018)

Spatio-temporal pattern and driving forces of urbanization in China’s border areas

Border area is not only an important gateway for inland opening-up, but also an important part of completing the building of a moderately prosperous society and optimizing national urban spatial pattern in China. Due to the location, natural resources endowment, and traffic accessibility, the urbanization speed is relatively slow in border areas. Therefore, it is a special area that needs to pay close attention to, especially under the background of the Belt and Road Initiative and China’s regional coordinated development program. Based on the county-level data from 2000 to 2015, this paper tries to analyze the spatio-temporal pattern of urbanization in 134 border counties, and applies geographical detector method to study the driving forces of urbanization in border areas. Conclusions are as follows: (1) From 2000 to 2015, urbanization rate in border areas has been lower than the national average, and the gap has been widening. Some border counties in southern Xinjiang, Tibet, northeast of Inner Mongolia, and Yunnan, are even facing the problem of population loss. (2) In the same period, urbanization rate in the northwestern and southwestern border is low, while their urbanization rate grows relatively faster comparing with other border counties; urbanization rate in Tibet border is the lowest and grows relatively slowly; urbanization rate in the northeastern and northern border is slightly higher, but it grows slowly or even stagnates. (3) Transportation and industry are the important driving forces of urbanization in border areas, while the driving forces of market is relatively weak. And there are obvious mutual reinforcements among the driving forces, while the effort and explanatory power of resource force increases obviously after interaction. (4) Urbanization rate in the northwestern and southwestern border areas grows relatively fast, with industrial force and transportation force, market force and administrative force as the main driving forces respectively. Tibet border area has the lowest urbanization rate and growth rate, as the driving force of urbanization with strong contribution has not yet formed in Tibet. In the northeastern and northern border areas, the contribution of transportation force to urbanization is greater than other forces, and its interaction with market and industry has obvious effects.

Porphyry Body and Geological Structure Identification as Control of Low Sulphidation Epithermal System in Sangon, Kokap Sub-District, Kulonprogo Regency, Special Region of Yogyakarta, Indonesia

There is gravity measurement that is supported by magnetic measurement in Sangon to identify porphyry body and geological structure as low sulfidation epithermal system control. The survey area is 6.4 x 5.6 km for gravity method and 2.5 x 1.2 km for the magnetic method. The value of gravity anomaly after flat plane reduction processing is 122-142 mGal which is positive anomaly located in the north-eastern area and negative anomaly to 82- 102 mGal located in the south-western area. Whereas the magnetic residual anomaly is - 800-1300nT.Conducted 2.5 D modelling of gravity method that is based on local anomaly slice. The result of 2.5D modelling show that an intrusion body interpreted as Dacite intrusion as host rock which plays a role as a heat source of the mineralization system. The density of Dacite is 2.70 gr/cm3. The result of gravity modelling has a correlation with the result of magnetic modelling. Based on magnetic modelling, the intrusion body is located in the south-west.

Toxoplasma gondii in small ruminants in northeastern areas of Colombia: Seroprevalence and risk factors

Sheep and goats are susceptible to infections with Toxoplasma gondii and could play an important role in the transmission of the zoonotic parasite to human. We conducted a cross sectional study to estimate the seroprevalence and to assess the risk factors for T. gondii seropositivity in small ruminants under traditional husbandry systems. This study was carried out from November 2015 to April 2016 in randomly selected small ruminants (n = 1038) from 48 farms located in Colombia, in the departments of northern Cesar in the north and La Guajira in the south. An indirect ELISA was used to detect IgG antibodies to T. gondii in the animals. A standardized questionnaire was used to obtain information on putative risk factors. We conducted the association analyses by using univariable and multivariate logistic regression and report odds ratios (OR) with 95% confidence interval (C.I). The overall seroprevalence in small ruminants was 23.5% (C.I: 21–26.2%). Sheep showed a higher seroprevalence (25.1% C.I: 22.4–28.6%) than goats (18.4% C.I: 22.4–28.6%). The association analysis recognized as risk factors for T. gondii seropositivity farming pigs in addition to small ruminants (OR = 1.96 C.I: 1.414–2.743), the inexistence of manure heap (OR = 2.254 C.I: 1.480–3.433) and drinking water from locally aqueducts (OR = 1.489 C.I: 1.006–2.204). The results of the study confirmed that exposure to T. gondii is common in sheep and goats in dry Caribbean regions of Colombia.

Modeling the Impact of Urbanization on Land-Use Change in Bahir Dar City, Ethiopia: An Integrated Cellular Automata–Markov Chain Approach

The fast-paced urbanization of recent decades entails that many regions are facing seemingly uncontrolled land-use changes (LUCs) that go hand in hand with a range of environmental and socio-economic challenges. In this paper, we use an integrated cellular automata–Markov chain (CA–MC) model to analyze and predict the urban expansion of and its impact on LUC in the city of Bahir Dar, Ethiopia. To this end, the research marshals high-resolution Landsat images of 1991, 2002, 2011, and 2018. An analytical hierarchy process (AHP) method is then used to identify the biophysical and socioeconomic factors underlying the expansion in the research area. It is shown that, during the period of study, built-up areas are rapidly expanding in the face of an overall decline of the farmland and vegetation cover. Drawing on a model calibration for 2018, the research predicts the possible geographies of LUC in the Bahir Dar area for 2025, 2034, and 2045. It is predicted that the conversions of other land-use types into built-up areas will persist in the southern, southwestern, and northeastern areas of the sprawling city, which can mainly be traced back to the uneven geographies of road accessibility, proximity to the city center, and slope variables. We reflect on how our findings can be used to facilitate sustainable urban development and land-use policies in the Bahir Dar area.

Variation in Phytoplankton Community Due to an Autumn Typhoon and Winter Water Turbulence in Southern Korean Coastal Waters

We evaluated changes in the phytoplankton community in Korean coastal waters during October 2016 and February 2017. Typhoon Chaba introduced a large amount of freshwater into the coastal areas during autumn 2016, and there was a significant negative relationship between salinity and nutrients in the Nakdong estuarine area, particularly in the northeastern area (Zone III; p < 0.001). The abundance of diatom species, mainly Chaetoceros spp., increased after this nutrient loading, whereas Cryptomonas spp. appeared as opportunists when there was relatively low diatom biomass. During winter, biotic and abiotic factors did not differ among the surface, middle, and lower layers (p > 0.01; ANOVA), implying that water mixing by winter windstorms and low surface temperature (due to the sinking of high-density water) physically accelerated mixing of the whole water column. Diatoms predominated under these conditions. Among diatoms, the centric diatom Eucampia zodiacus remained at high density at the inshore area and its abundance had a negative correlation with water temperature, implying that this species can grow at cold temperatures. On the other hand, the harmful freshwater diatom Stephanodiscus hantzschii mainly appeared in conditions with low salinity and high nutrients, implying that it can persist even in the saltwater conditions of the Nakdong Estuary. Our results indicate that hydro-oceanographic characteristics, such as river discharge after an autumn typhoon and winter water turbulence, have major effects on the composition of phytoplankton communities and can potentially affect the occurrence and characteristics of harmful algal blooms in southern Korean coastal waters.

Geophysical approach to study the potential ocean wave-induced liquefaction: an example at Magoodhoo Island (Faafu Atoll, Maldives, Indian Ocean)

This paper presents an application of geophysical techniques to determine the liquefaction potential of the surface sand layer under wave loading in an atoll island, Magoodhoo Island (Faafu Atoll). Measurements of background noise (H/V technique), seismic refraction profiles (tomography), surface wave inversion and electrical resistivity tomography were applied to study the properties of the substratum. Geotechnical analysis provided the relative soil density (Dr = 55%) and the grading curves; the comparison of these parameters with geophysical data, allowed to identify indicative features related to ground liquefaction phenomena. Microtremor measurements calculated a fundamental site resonance in the frequency range of 1.42–23.19 Hz. Velocity profiles showed that bedrock interface depth varies from approximately z = 35 m north-east of the island, to z = 25 m south-west, while in the most north-eastern external area, it was not detected. These results suggested a significant lateral variability of the site seismic response throughout the study area. Liquefaction triggering with wave heights varying between 2.0 and 3.0 m and 70–300 cycles was calculated. Also, considering an average wave period of 6 s, liquefaction was more likely after 7–30 min. The soil vulnerability index Kg was also used to evaluate the soil liquefaction hazard suggesting that the north-eastern island sector is more susceptible to liquefaction, confirmed also by the building damage status as compared to other areas of the island. The results obtained in the survey highlight that in an atoll island, where potential disasters can be caused by several natural causes, saturated loose sands lose their strength and stiffness if subjected to wave loading.

Uneven development within China: Implications for interprovincial energy, water and arable land requirements

Owing to uneven development and unbalanced resource endowments within China, ensuring reliable energy, water and food supply is a core challenge to regional socio-economic development. This study makes a first attempt to examine and compare demand-driven energy, water and arable land (E-W-L) resource outsourcings within China based on the latest multi-regional input-output model. Results show that interprovincial trade reallocated 73.4%, 33.9% and 38.1% of the national total E-W-L resource inputs in 2012, respectively. Investment was the dominant final demand category for driving energy requirements, while consumption was the leading final demand category for water and arable land requirements. Important provincial regions and critical transmission sectors for the trade of embodied E-W-L resources are identified. Substantial E-W-L resources were transferred from the central and western regions to the eastern regions. Especially, Inner Mongolia was the top interregional net exporter of embodied energy, while Jiangsu topped the net importer list. Regarding virtual water transfer, Xinjiang and Shandong were the biggest interregional net exporters and net importers, respectively, while Heilongjiang and Guangdong stood out in the net trade of embodied arable land. Owing to the impact of interprovincial trade, the resource occupancy levels of the eastern developed area were much higher than those of the northeastern, central and western areas. The imbalances in the levels of socio-economic development amongst provincial regions are mirrored by their patterns of E-W-L uses and related trade transfer. Understanding the synchronal outsourcings of E-W-L resource requirements provides important implications for targeted resource management in Chinese interprovincial supply chains.

The Agglomeration of Manufacturing Industry, Innovation and Haze Pollution in China: Theory and Evidence.

Haze pollution in China is a serious environmental issue, which does harm both to people’s health and to economic development. Simultaneously, as an important industrial development law, agglomeration may result in the increased concentration of manufacturing firms and, consequently, an increase in haze pollution. However, the positive externalities of agglomeration can also improve the efficiency of regional innovation, which curbs haze pollution. In this paper, we construct both theoretical and empirical models to investigate the effects of industrial manufacturing agglomeration on haze pollution. The results reveal the following: (1) By incorporating the effect of agglomeration and haze pollution into a general endogenous growth model, we show an inverted-U relationship between agglomeration and haze pollution on the balance growth path. (2) Based on data concerning haze pollution (PM2.5) and data from 285 Chinese cities, the empirical results verify the findings of the theoretical model. Further, we calculated the values of agglomeration variables, with respect to the inflection points of the inverted-U, which the cities need to reach in order to gain the specific agglomeration values required to enjoy the inhibition effect of agglomeration on haze pollution. (3) A heterogeneity analysis shows that the inverted-U relationship is more obvious among the cities in the middle and northeastern areas of China, as well as medium-size cities. (4) Cities’ environmental regulation policies and high-quality institutional environments can restrain the positive effect of agglomeration on haze pollution. (5) Using three measures of innovation, it is also empirically found that innovation is the mechanism (mediator) between agglomeration and haze pollution.

Population Dynamics and Distribution Patterns of Diurnal Raptors in Northeastern Algeria: Seasonal Variation and Some Nesting Characteristics

Abstract Providing a live data monitoring of raptor abundances and spatial localization of their most important nesting areas is very helpful in building a strong future study and applying a sound strategy for effective safeguarding of these emblematic species. Using geographic information system (GIS) and global positioning system (GPS) techniques, we investigated spatial patterns of raptors distribution in the northeastern areas of Algeria during two consecutive breeding seasons (2014 and 2015). The total area sampled (31,000 km2) host diverse raptor species (14 species), among them, the threatened species Egyptian vulture (Neophron percnopterus; 108 individuals and 19 active nests) and red-footed falcon (Falco vespertinus; 12individuals). The value of the region is attested by the presence of an abundant population of nesting black kite (Milvus migrans; 337 individuals). The large-scale spatial analyses of the studied region illustrate certain similarities in nesting habitat selection among raptors. Almost all species (90% of 209 nests detected) preferred to nest within multispecies assemblages (20 raptor assemblages found) and occupied altitudinal rocky cliffs across the inland region (semi-arid zones) rather than coastal region (sub-humid zones). Among all raptor species, exclusively, the common kestrel (Falco tinnunculus) is relatively synanthropic, because it was found to breed within cities (tolerate human activities). The raptor community in the coastal versus inland regions differed by 14%. The latter area seems to be more preferred in nest building, probably consequence of their semi-arid bioclimatic and landscapes characteristics, where high elevations and grasslands forming mosaics with Oak, Alpine, and Cedar forests are patchily distributed. The study is a first mapping database of important nesting sites dispatched across the northeastern areas of Algeria, and it can be effectively used in future complementary researches that aim to elucidate environmental factors that affect raptors life cycle.

An Integrated Framework for Extreme Drought Assessments Using the Natural Drought Index, Copula and Gi* Statistic

This study proposes a framework to evaluate extreme drought using the natural drought index, copula and hot spot analysis. The study area was South Korea. Data were used from 59 automatic synoptic observing system stations; the variable infiltration capacity model was used for the period from 1981 to 2016. The natural drought index was constructed from precipitation, runoff and soil moisture data, which reflect the water cycle. The average interval, duration and severity of extreme drought events were determined following Runs theory. The most extreme drought period occurred in 2014–2016, with 46 of the 59 weather stations exhibiting drought conditions and 78% exhibiting extreme drought conditions. The Inje and Seosan stations exhibited the longest drought duration of 6 months, the most severe drought was 5 times higher than the extreme drought severity threshold. The periods and locations of extreme drought were identified using the natural drought index corresponded to the historical droughts in South Korea. Furthermore, the joint return period of 50 years indicated the northeastern area of South Korea suffered from long-lasting and severe drought. Meanwhile, hot spot analysis was used to explore the extreme drought conditions and showed an increasing trend in the middle and northeastern parts of South Korea. Overall, this framework provides water resource managers with essential information about extreme events, extreme joint return periods, locations and significant trends of natural drought that have not been considered before.

Integrated Geospatial Database and Web Based Tools for Land Management and Administrative Planning (ILMAP) for Imphal East and Thoubal Districts, Manipur State, India

Manipur, as most of the north eastern area, come under hilly and difficult area, economically and infrastructurally underdeveloped area category. Manipur is facing the unenviable situation of being a resource starved State coupled with decades old insurgency widespread across the State, desperately crying out for a major thrust in inclusive development. As part of the initiative by the Govt. of India for the development of the north-eastern India, an Integrated Land Management and Administrative Planning (ILMAP) was taken up in Manipur State with the state-of-the-art technology. In the present work Imphal East and Thoubal Districts are selected. The objective of the study is to generate GIS database on drainage, water bodies, administrative boundaries, and other utility maps. The methodology involves geo-referencing of Quick Bird (QB) data with the help of DGPS survey. Drainage and surface water bodies, base map and land use/land cover maps are generated with the help of QB data. Point of Interest is mapped in all urban areas covering important landmarks such as Govt. offices, post offices, banks, religious places, and places of tourist interest etc., along with photographs and geographical coordinates. Using the soil maps generated by AISLUS and NBSS and LUP as a base, soil maps are prepared. All these maps are geo-referenced to QB satellite data. Using this database, a customized GIS application is developed for e-governance which can be accessed by authorized beneficiaries through State Wide Area Network (SWAN). The application was deployed in the State Data Centre (SDC) and training was provided to all the department officials for effective use in all developmental projects.

A Land Space Development Zoning Method Based on Resource-Environmental Carrying Capacity: A Case Study of Henan, China.

As a key element in China’s spatial planning, the development zoning of land space has become a focus of China’s current activity. During its rapid social and economic development, China has faced severe and diverse challenges regarding sustainable development, such as farmland occupation, environmental degradation, urban land disorder expansion, etc. Against this backdrop, research on the linkage between resource–environmental carrying capacity (RECC) and the development zoning of land space in the process of sustainable development has received increased attention, and an accurate evaluation of the RECC would provide useful guidance for Chinese policy makers to carry out the development zoning of land space. This paper uses Henan Province as an example to construct a comprehensive evaluation model of “resource carrying capacity (RCC)–eco–environmental carrying capacity (EECC)–socio–economic carrying capacity (SECC)”, which calculates the level of RECC in a provincial area. In addition, this paper designs a correlation model between the RECC and the development zoning of land space, which uses a three-dimensional magic cube evaluation model to analyze the development zoning layout of land space. The results showed that a geographical pattern exists, where in the southwestern areas of Henan Province have a higher RECC than the central and northeastern areas. The results also indicated that the land space patterns of Henan Province can be divided into seven types of areas through a three-dimensional magic cube evaluation model, which can better reflect the spatial differentiation characteristics of the comprehensive index of RECC. The results of this study offer an important reference for policy-makers to make decisions and also provide a scientific and pragmatic basis for the formulation of sustainable development strategies.

Spatiotemporal Analysis of Vegetation Cover and Its Response to Terrain and Climate Factors in Duhok Governorate, Kurdistan Region, Iraq

The integration of remote sensing techniques and Geographic Information System has a wide use to quantify the spatial and temporal distribution of vegetation cover. Over the last decade, a remarkable change was noticed in both climate and vegetation cover in Duhok. The Modified Soil Adjusted Vegetation Index (MSAVI2) was extracted from Landsat satellite images over the 20 years (2000 to 2019). For analyzing the vegetation changes, the terrain data including elevation, slope, and aspect and climate data temperature and precipitation are used. The result shows that from 2000–2019, the average mean MSAVI2 is 0.361 and the trend increased in 77.9% of the study area. The northern and northeastern areas of the study area revealed a significant increase in vegetation, while in the low land areas it is decreased. The amount of precipitation and temperature degree affect the spatiotemporal distribution of vegetation cover. The MSAVI2 showed a positive relationship with precipitation and temperature. At elevation less than 2000 m, with increasing elevation the MSAVI2 is increasing, but when the elevation reaches 2000 m, the MSAVI2 is decreasing and negatively related to elevation. The vegetation has a positive relation with slopes less than 45°, and at slopes higher than 45°, the MSAVI2 is decreased. The impact of aspect on the vegetation figured out that the largest MSAVI2 is detected in the shady slope due to relatively less evapotranspiration.

Quantifying long-term variability of precipitation and temperature over Zambia

A cursory or even detailed inspection of literature shows that while the annual cycle of precipitation and temperature in Zambia are well understood, there is a general lack of documentation on long term trends and periodicities over the country. In this study, we extensively examined the temporal and spatial changes in precipitation and temperature over Zambia for the period 1950–2016. We used the modified Mann–Kendall (m-MK) test with the aim of eliminating the effect of autocorrelation on precipitation and temperature trends based on Global Precipitation Climatology Centre (GPCC) and National Centre for Environmental Prediction/National Centre for Atmospheric Research (NCEP/NCAR) products. Overall, significant decrease (increase) in precipitation (temperature) was evident. We further observed that, on average, precipitation has been decreasing by 1.1 mm yr−1. The highest drying rate was observed recently in the 2010s with a decrease of −24.4 mm/year. An abrupt change in the trend of precipitation was reported in 1980/1981 significant at 5% significance level. The highest amount in mean annual rainfall was 1093.5 mm reported in the 1960s while the lowest (966.4 mm) was reported in the 1990s. During the core of the rainy season, the western and southern provinces of the country are observed to generally experience negative rainfall anomalies implying more precipitation deficits in these areas. Temperature has been observed to be on the rise since the 1980s and no sudden changes have been observed in its trend over the country. Results further indicate that temperature has been increasing at a rate of 0.01 °C yr−1. The highest temperature increment (0.08 °C yr−1) was observed in the 2000s. Spatial analyses showed that temperature anomalies were positive across the whole country with higher anomalies being manifested in the 2000s and 2010s especially across North-eastern areas of the country. Findings embodied in this work provide a strong foundation for future climate monitoring and for studies that focus on examining extreme weather phenomena over Zambia.

Effects and Correction of Atmospheric Pressure Loading Deformation on GNSS Reference Stations in Mainland China

Atmospheric pressure loading (APL) deformation is one component of nontectonic deformation for Global Navigation Satellite System (GNSS) time series and is a kind of deformation response caused by a redistribution of atmospheric pressure. In this paper, we present an atmospheric data processing strategy to compute the APL based on a spherical harmonic expansion of the global atmosphere pressure changes. We also provide a sample model to describe the relativity between the global atmosphere pressure changes and APL vertical deformation. The results show that the variation of air mass has a major impact on the north-eastern area of East China, the eastern area of North China, and Northeast China, and the vertical crustal displacement caused by the atmosphere changes in these regions can reach about 20 mm. The correction of APL for vertical time series of GNSS reference stations in different regions indicates that the arid area of the Northwest China, Northeast China, Central China, and North China are greatly affected by APL. While for the station located in Sichuan-Yunnan region, the amplitude and period change are small after correction of APL for vertical time series of GNSS reference stations, which reveals that the area is seriously affected by tectonic movement and water migration loading. The correlation between atmospheric pressure changes and crustal deformation is analyzed, which shows that APL has a serious impact on the north-eastern area of North China, the Northeast China, and the eastern area of Central China when the variations in atmospheric pressure in mainland China are the same. The research results of this paper will provide some reference value for the study of crustal structural deformation and the establishment of geodetic datum.