Northwestern Area Research Articles

The Accessibility of Educational Public Service Facilities with Two-Step Mobile Search Taking Hetao District of Ganzhou City as an Example.

By using the two-step mobile search method of time and distance cost combined with Internet map data, taking the old urban district of Ganzhou city as research object, the spatial accessibility of primary and secondary schools from residential sites to residential areas was studied. The research shows that the reachability of primary and secondary schools in the old urban district of Ganzhou city is low, and most of the population fails to enjoy better education resources and the spatial distribution of education resources is not balanced. The reachability of primary education resources is high in geospatial area. The gathering area is the intersection of Ganjiang Street and Jiefang Street. The low-value areas are mainly the southwestern part of Nanwai Street and the northwestern area of Dongwai Street. The reachability of education resources shows a decreasing trend from the center to the surrounding areas. The education resources are concentrated in Ganjiang Street. Compared with traditional methods, the two-step mobile search method using Internet map data can more effectively and accurately reflect the accessibility of residential areas to primary and secondary schools in real time and can obtain the real conditions of traffic and roads more conveniently and also more accurat data acquisition.

Landscape pattern change and its correlation with influencing factors in semiarid areas, northwestern China

The West Liaohe Plain (WLP) is a typical crop-pastoral ecotone of the semiarid area in Northwestern, China. Land use/cover change (LUCC) of the WLP might endanger this ecosystem, triggering long-lasting environmental concerns. LUCC data for China (1980–2020) and hydrometeorological data were analyzed to reveal factors contributing to change and explore sustainable development opportunities. The results show that characteristics of the main land-use types in the WLP have changed significantly, especially cultivated land area, which increased by 15.2% and 6.79% during the periods 1980–1995 and 2000–2020, respectively. Response relationships were observed due to natural (precipitation, temperature, and runoff) and anthropogenic (economy) factors and LUCC. Between 2000 and 2020, the impact of anthropogenic factors on cultivated land was stronger than on grassland at the class and landscape level, using the landscape indices which were selected, including percent of landscape (PLAND), number of patches (NP), largest patch index (LPI), and Shannon's evenness index (SHEI). Expansion of cultivated land from 1990 to 1995 was not only related to anthropogenic factors but also to hydrological & climatic factors. The results of this study have the potential to influence sustainable land resource development.

Assessing the Lead Accumulation Risks of Wheat Grain by Developing a Source-Specific Accumulation Risk Assessment Model

Characterizing the lead (Pb) transfer in the "source-soil-wheat" chain is of great importance for the prevention and control of the Pb accumulation risk in wheat grain harvested from the croplands of China. In this study, we used the Jiyuan City, northern China, as a case study to investigate the influence of contamination sources and soil factors on the accumulation of Pb in wheat grain. A site-specific source risk assessment model (SRAM), coupling the positive matrix factorization model, Freundlich-type function, and the Monte Carlo simulation method, was developed to estimate the risk of Pb accumulation in wheat grain harvested from different scenarios. Based on the results of the spatial analysis, the effectiveness and potential risk of the control measures applied in the study area was also evaluated. Atmospheric deposition and phosphate fertilizer application were identified as major sources contributing to 29.0% of the Pb accumulations in wheat grain. Soil pH and cation-exchange capacity (CEC) were the primary causative factors affecting the Pb accumulation in wheat grain. Cropping wheat in the high Pb continuation risk areas (western and northwestern areas) of Jiyuan City caused a 10.5% likelihood of Pb to accumulate above the China food standard limit of 0.2 mg·kg-1 (DW). This risk was significantly decreased to 2.39% when the CEC levels of affected soils was improved to 20 cmol·kg-1 and above.

Potato (Solanum tuberosum L.) Growth and Quality as Influenced by Inorganic Fertilizer Rates in Northwestern Ethiopia

Potato (Solanum tuberosum L.) is an important tuber crop that is highly affected by poor soil fertility and nutrient disparities. Nutrient depletion due to intensive monocropping and poor soil management practices is a serious problem in Ethiopia, including in northwestern areas. Therefore, an experiment was conducted in the East Gojjam zone of northwestern Ethiopia to evaluate the influence of phosphorus and potassium fertilizer rates on potato tuber production. Three phosphorus levels (0, 34.5, and 69 kg/ha−1) and four potassium levels (0, 100, 200, and 300 kg/ha−1) were set out in a factorial arrangement and replicated three times using a randomized complete block design. Data on growth and quality parameters, as well as plant tissue analysis results, were collected. According to the results, the main effects of phosphorus and potassium fertilizer rates statistically affected growth components. The combined effects of phosphorus and potassium fertilizers had a significant influence on quality components (tuber size distribution). Similarly, the interaction effects of phosphorus and potassium fertilizer rates gave the highest response in all nutrient use efficiency parameters. The combined application of 34.5 kg P2O5 and 200 kg K2O fertilizers resulted in the highest medium (28.32 ton/ha−1) and large-sized (20.0 ton/ha−1) tuber yields. The interaction effect of 34.5 kg P2O5 with 100 kg K2O ha−1 yielded the highest agronomic and recovery efficiency values. Hence, a combination of 34.5 kg P2O5 ha−1 and 200 kg K2O ha−1 fertilizer rates can be recommended for the optimal production of potato in the northwestern area.

Growth and Distribution of Coal-Measure Source Rocks in Mixed Platform: A Case Study of Carboniferous in Bamai Area, Southwest Tarim Basin, China

Coal-measure source rocks are generally developed in marsh facies under a humid climate and are rarely reported in a carbonate platform or a mixed platform. Carboniferous seawater intruded from west to east in the Tarim Basin, and mixed platform deposits of interbedded mudstone and carbonate developed in the southwest of the basin. In recent years, with the deepening of the exploration, nearly 20 m coal seams and carbonaceous mudstone source rocks have been found in the Carboniferous lagoon’s tidal-flat background. The hydrocarbon generation potential, development, and distribution of these coal-measure source rocks have become an important issue for oil and gas exploration. Coal seams and carbonaceous mudstones were found in the Carboniferous formation of wells BT5, BT10, and Lx2. The hydrocarbon prospect, development, and distribution characteristics of these coal formations have become an important research topic. The authors conducted organic geochemical tests and analyses of core and samples drill cuttings from multiple wells in the study area, combined with research focused on the identification and distribution of coal seams, dark mudstones, and depositional facies via logging cross plots of different lithology and 3D seismic inversion. The results show that coal-measure source rocks in the BT5 well are related to the set of delta-lagoon sedimentary systems widely developed in the Carboniferous Karashayi Formation. The maximum cumulative thickness of coal-measure source rocks is about 20 m, with total organic carbon (TOC) contents of 0.15–60%, kerogen types II2-III, and vitrinite reflectance (Ro) values of 0.78–1.65%. The rocks have generally low maturity in the northwestern area and high maturity in the southeastern area, and the maturity changes as the burial depth changes. The effective hydrocarbon source rocks such as coal, carbonaceous mudstone, and dark mudstone all show acoustic time (AC) greater than 300 µs/m, and density (DEN) less than 2.3 g/cm3, but possess different gamma ray (GR) values. The GR value is less than 75 API for coal, between 75–100 API for carbonaceous mudstone, and greater than 100 API for dark mudstones. The distribution of source rocks can be identified in the area between the wells according to a 3D seismic inversion impedance (IMP) of less than 7333 m/s·g/cm3. The development and controlled factors of coal-measure source rocks of delta facies in the mixed platform have a significant role for oil and gas exploration of Upper Paleozoic in this area. The coal measure and sandstones of delta in the Carboniferous are expected to form self-generation and self-storage pools in this area.

Inequalities in caries among pre-school Italian children with different background

BackgroundThe study was aimed to describe caries prevalence and severity and health inequalities among Italian preschool children with European and non-European background and to explore the potential presence of a social gradient.MethodsThe ICDAS (International Caries Detection and Assessment System) was recorded at school on 6,825 children (52.8% females). Caries frequency and severity was expressed as a proportion, recording the most severe ICDAS score observed. Socioeconomic status (SES) was estimated by mean a standardized self-submitted questionnaire filled-in by parents. The Slope Index of Inequality (SII) based on regression of the mid-point value of caries experiences score for each SES group was calculated and a social gradient was generated, children were stratified into four social gradient levels based on the number of worst options. Multivariate regression models (Zero-Inflated Negative Binomial logistic and logistic regression) were used to elucidate the associations between all explanatory variables and caries prevalence.ResultsOverall, 54.4% (95%CI 46.7–58.3%) of the children were caries-free; caries prevalence was statistically significant higher in children with non-European background compared to European children (72.6% vs 41.6% p < 0.01) and to the area of living (p = 0.03). A statistically significant trend was observed for ICDAS 5/6 score and the worst social/behavioral level (Z = 5.24, p < 0.01). Children in the highest household income group had lower levels of caries. In multivariate analysis, Immigrant status, the highest parents’ occupational and educational level, only one kid in the family, living in the North-Western Italian area and a high household income, were statistically significant associated (p = 0.01) to caries prevalence. The social gradient was statistically significant associated (p < 0.01) to the different caries levels and experience in children with European background.ConclusionsData show how caries in preschool children is an unsolved public health problem especially in those with a non-European background.

The Toda Women’s Embroidery Enterprise: The Commercialization of a Traditional Craft in South India

The Todas are a small but very well documented indigenous community of erstwhile buffalo pastoralists, who live atop the Nilgiri Mountains in the far northwestern area of Tamil Nadu State in South India. The Toda women’s long tradition of embroidering items of clothing—notably cloaks and loincloths—to be used within the community and as important items of exchange with neighboring indigenous communities, has developed exponentially over the past hundred years or so. It is now a significant cash earner for many Toda women and their households. Over the past fifty or more years, this unique embroidery enterprise— the sole preserve of the community’s womenfolk—has increasingly caught the attention of textile and design specialists working for India’s fast-developing fashion industry. The data in this paper are organized in three major parts: the first introduces some of the principal socio-cultural characteristics of the Toda community, the second examines the traditional situation of women in this patriarchal society, while the final section concentrates on the development of the Toda women’s embroidery enterprise, in terms of design, production skills and commercial prospects.

Influence of circulation types on temporal and spatial variations of ozone in Beijing

This study analyzes the impact of circulation types (CTs) on ozone (O3) pollution in Beijing. The easterly high-pressure (SWW) circulation occurred most frequently (30%; 276 day), followed by northwesterly high-pressure (AN) circulation (24.3%; 224 day). The SWW type had the highest O3 anomaly of +17.28 µg/m3, which was caused by excellent photochemical reactions, poor diffusion ability and regional transport. Due to the higher humidity and precipitation in the low-pressure type (C), the O3 increase (+8.02 µg/m3) was less than that in the SWW type. Good diffusion/wet deposition and weak formation ability contributed to O3 decrease in AN (-12.54 µg/m3) and northerly high-pressure (ESN) CTs (-12.26 µg/m3). The intra-area transport of O3 was significant in polluted circulations (SWW- and C-CTs). In addition, higher temperature, radiation and less rainfall also contributed to higher O3 in northern Beijing under the SWW type. For the clean CTs (AN and ESN CTs), precursor amount and intra-area transport played a dominant role in O3 distribution. Under the northeasterly low-pressure CT, better formation conditions and higher precursor amount combined with the intra-area southerly transport to cause higher O3 values in the south than in the north. The higher O3 in the northwestern area under the northeasterly high-pressure type was influenced by weaker titration loss and high O3 concentration in previous day. Annual variation in the CTs contributed up to 86.1% of the annual variation in O3. About 78%-83% of the diurnal variation in O3 resulted from local meteorological factors.

Effects of Winter Heating on Urban Black Carbon: Characteristics, Sources and Its Correlation with Meteorological Factors

Coal combustion for winter heating is a major source of heavy atmospheric pollution in China, while its impacts on black carbon (BC) are not yet clear. A dual-spot Aethalometer was selected to monitor the atmospheric BC concentration in Zhengzhou, China, during the heating season, which is from 15 November through 15 March of the following year, and the non-heating season (days other than heating season). The characteristics and sources of BC were analyzed, and a concentration weight trajectory (CWT) analysis was conducted. The results showed that the BC concentrations in the heating season were generally higher than those in the non-heating season. The diurnal variation in BC concentrations during heating season was bimodal, and that during the non-heating season was unimodal. The α-values in the heating and non-heating seasons indicated that combustion of coal and biomass and vehicle emissions were the major BC sources for the heating season and non-heating season, respectively. BC concentrations were positively correlated with PM2.5, PM10, CO, and NOX. There was a strong negative correlation between wind speed and BC concentrations, and that for relative humidity was the opposite. BC concentration during heating season was mainly influenced by the northwestern areas of China and the eastern part of Henan, and that in the non-heating season was mainly from the northeastern areas of China and southern Henan.

Revised stratigraphy in the eastern Meguma terrane, Nova Scotia, Canada, and variations in whole-rock chemical and Sm–Nd isotopic compositions of the Goldenville and Halifax groups

As a result of new geological mapping, the Goldenville and Halifax groups in the eastern Meguma terrane have been divided into formations. They have a total stratigraphic thickness of about 7750 m and correspond to only the upper half of the Goldenville Group and lower half of the Halifax Group in the northwestern and southeastern areas of the terrane. The revised stratigraphy combined with compiled and new whole-rock major and trace element and Sm–Nd isotopic analyses enable more detailed documentation of the chemical changes with stratigraphy that were demonstrated in previous studies. Based on chemical compositions, the protolith compositions of the analysed samples range from lithic arenite to wacke to shale. Major and trace element characteristics are consistent with deposition in an active continental margin, basins associated with island arcs, or most likely at a passive continental margin with volcanic rocks in the source area. Chemical compositions show a scattered but overall increasing abundance of lithophile elements such as La and Th with stratigraphic position. Epsilon Nd(t) values become increasingly negative up-section, and depleted mantle model ages become increasingly older. The data are consistent with increased mixing between sediments derived from Mesoproterozoic upper crustal sources and sediments derived from a magmatic arc. These data are consistent with published detrital zircon patterns which show increasing amounts of ca. 2 Ga zircon with decreasing age, and with a source area comprising a Pan-African (800–540 Ma) volcanic arc and/or active margin magmatism and mainly Eburnean crust, most likely in the West African craton.

Spatial-temporal evolution of the source-to-sink system in the northwestern South China Sea from the Eocene to the Miocene

The northwestern South China Sea (NW-SCS) presents a spatial-temporal evolution of its source-to-sink (S2S) system, that recorded the movement of the Indochina block and the collision between the Indian and Eurasian plates. However, complex tectonic movements and topographic evolution have led to controversial studies about the spatial-temporal distribution of allogenic materials and autogenic sediments. In this study, we integrated a number of multiscale data to review the S2S system evolution of the northwestern area of the South China Sea from the Eocene to the Miocene. The series include the initial synrift, postrift and thermal subsidence stages. First, we identified the major sediment pathways using seismic profile interpretation. We reconstructed the sediment distribution and lithofacies association within the dispersal sink area based on seismic data, core samples and grain-size analysis. We quantitatively studied the sediment flux and catchment area based on mass balance calculation modeling. Following this, we acquired rare-earth element (REE) data and zircon U–Pb age data from the bedrocks of the continental blocks and the South China Sea Cenozoic basement and rivers in the NW-SCS area to restore the provenance area and evaluate the migration distance by inspecting the heavy mineral assemblages. According to the above studies, three phases of S2S dynamics were identified. 1) The initial rifting stage occurred during the Eocene, and active rifting in the South China Sea induced a major topographic change. A large amount of autogenic slump sediments and a smaller amount of paleo-Red River sediments were injected into the Beibu Gulf Basin (BBGB) and the Yinggehai-Song Hong Basin (YGHB). 2) The postrift stage occurred during the Oligocene. Regional uplift and tectonic inversion probably linked to the clockwise rotation of the Indochina Block, broke the connection between the Beibu Gulf Basin and the Red River catchments. The paleo-Qin River and the paleo-Lian (Nanliu) River brought a large amount of clastic material into the Beibu Gulf Basin from the Cathaysia Block. 3) The thermal subsidence stage occurred during the Miocene: the eastward topographic tilt was enhanced, and the drainage basin entered postrift stage. The development of the Paleo-Red River and its branches, the Lam River and the Ma River, brought distal sediment into the YGHB, while the rivers in the west Cathaysia Block transported sediment into the BBGB. Statistical analysis of the S2S system parameters suggests that the average terrain altitude played a dominant role in determining the S2S system volume during the Eocene, while the dominant role transferred to the sediment supply during the Oligocene and Miocene. • Reconstructs the Source to sink system within NW-SCS from the Eocene to the Miocene. • Reveal the drainage evolution of basins in NW-SCS with multiple dates. • Put out the impact factors to the Source-to-Sink system developed during the rifting process.

An Archaeological landscape of Sharif Abad (Solgi) settlement area in the Gamasi-Ab River Basin in Central Zagros

Solgi or Sharif Abad tepe (A&amp;B) is one of the larger settlement sites of the Gamasi-Ab river basin in Nahavand plain. This site lies at the intersection of old ancient roads that go from Sahne, Harsin and Kangavar to Nihavand and the other eastern regions. In the study of this area, pottery from the Early Bronze Age (Godin IV-Yanik, Kura-Araxes), pottery related to Godin III, II and pottery of the historical period were obtained. The examination of these pottery artefacts reveals extensive cultural exchanges of the inhabitants of the region with the northwestern and neighboring areas in the Bronze and Iron Ages. In addition, a closer examination of the lifestyle in this settlement area gives us a complete view of these people’s use of biological resources and their interaction with the environment. Among the reasons for the location and development of this settlement in the Bronze and Iron Age the main one was easy access to water resources and fertile agricultural lands. This article provides a brief overview of the geographical situation of the region and the history of archaeological research conducted in Nihavand and then focuses on the natural landscape of Sharif Abad. The next part of it describes the archaeological data from this location and analyzes its chronology. The article is concluded by a succinct summary.

Occurrence, Distribution, and Risk Assessment of Antibiotics in the Aquatic Environment of the Karst Plateau Wetland of Yangtze River Basin, Southwestern China.

In this study, the occurrence, distribution, and ecological risk of 40 commonly used antibiotics, including 15 sulfonamides (SAs), 9 fluoroquinolones (FQs), 7 macrolides (MCs), 3 tetracyclines (TCs), 2 chloramphenicols (CAPs), and 4 other categories, in the aquatic environment of the karst plateau wetland Caohai of the Yangtze River basin in southwestern China are reported. In total, 27 antibiotics were detected, with the detection rate ranging from 5% to 100%. The total concentration at each site ranged from 21.8 ng/L to 954 ng/L, with the average concentration being 189 ng/L. FQs and MCs were the most predominant categories, contributing 29.3% and 25.0% of the total antibiotic burden. The five most commonly detected antibiotics were ciprofloxacin (CIP), oxytetracycline (OTC), acetyl sulfamethoxazole (ASMZ), norfloxacin (NOR), and florfenicol (FF). The spatial distribution of the total concentration at each site demonstrated a decreasing trend from the southeastern area upstream adjoining the main counties to the northwestern area downstream, indicating that human activities have a great impact. Meanwhile, the natural attenuation rates of different types of antibiotics in the direction of flow ranged from 17.6% to 100%, which implied the natural purification potential of the wetland for antibiotics. The cluster analysis results indicated that domestic sewage and wastewater from agriculture and animal husbandry were the main sources of contamination in the surrounding wetland. Risk quotients (RQs) assessment showed that most of the individuals were at low to medium risk and that the adverse risks posed by mixtures of antibiotics were higher than those posed by the individual antibiotics.

Distribution and Potential Ecological Risk Assessment of Heavy Metals in Sediments of Lake Qinghai

Lake Qinghai is the largest closed saltwater lake in China. In recent years, because of the rapid development of industry, agriculture, and tourism, the lake has been increasingly affected by human activities, which has attracted the attention of many scholars. In order to understand the distribution of heavy metals in the surface sediments of Lake Qinghai, the contents of Zn, Cu, Pb, Co, Ni, As, Cd, and Cr were investigated, the metal fractions were extracted, and the sources, as well as potential ecological risks, were analyzed. The results showed that:① the ω(As) (13.21 mg·kg-1) and ω(Cd) (0.21 mg·kg-1) in the surface sediments of Lake Qinghai were 1.13 and 1.53 times higher than the environmental background values, respectively, and the other heavy metal contents were all lower than the environmental background values. There were similar spatial distribution characteristics of analyzed metals except for As, with higher values measured in the northwestern area of the lake and the 151 Terminal. ② Except for Cd, the analyzed heavy metals mainly existed in the form of the residual state; by contrast, Cd mainly existed in the form of the bioavailable state, which has high potential toxicity to aquatic organisms. ③ Combined with the results of the correlation and principal component analysis, the metals including Zn, Cu, Pb, Co, Ni, Cd, and Cr were thought to mainly come from the natural environment, whereas the source of As was related to human activities, such as agricultural production. ④ According to potential risk analyses, the average of the metal potential ecological risk factors was 76.57, which indicated a slight ecological hazard level. However, it should be noted that the potential ecological hazard level and release risk of Cd at each site were higher than those of the other metals, especially in the regions nearing the estuary of Heima River, Lake Gahai, and the sand island, which showed higher levels of enrichment and potential release risk. Therefore, further attention should be paid to the potential impacts of Cd in sediments of these regions on the water environment and ecosystem.

Residential tower of the Koło castle in the light of the latest archaeological research

The Koło castle (Wielkopolskie voivodeship) is the best-preserved royal stronghold in the broadly defined historical province of Wielkopolska (Greater Poland). The castle owes this status not so much to the scale of the structures preserved to this day (i.e., ruins of the bergfried; the west curtain walls, still visible today in full length and considerable height; the greater part of the north curtain wall; and a section of the south one), but rather to the dilapidated condition of other castles founded by Polish monarchs. For a number of years (1977–1983), the Koło castle was subjected to archaeological research led by Łucja Pawlicka-Nowak (Regional Museum in Konin). Among other things, the excavations uncovered the residential tower discussed in thispaper. The excavations at the time covered the western half of the building’s interior, both of its outer southern corners, and the north-western area. The research was resumed in 2019, and the authors of this paper faced the challenge of verifying the earlier fieldwork, the extent of which was very wide and not fully documented. The investigations presented here shed completely new light both on the construction history of the Koło castle, and the issues concerning its chronology, which, in the light of current research, would have been as follows: Casimir the Great acquires the village and founds the town of Koło in 1362; the construction of the castle commences and the work on the site of the residential tower quickly progresses following 1365 (or 1367); the monarch dies in autumn 1370, before or shortly after the unfinished castle is consumed by fire. The article concludes with a chapter showing the Koło tower against the background of similar structures in Europe.

Erysiphe pakistanica (Erysiphaceae), a new species on Indian willows (Salix tetrasperma) from Pakistan

A new powdery mildew fungus, Erysiphe pakistanica (Erysiphaceae) infecting Indian willows is described from north-western areas of Pakistan. Identification is based upon morpho-anatomical features and molecular analysis. This species is characterized by having nipple-shaped appressoria, small chasmothecia and ascospores. Phylogenetic analysis of nrDNA of ITS and LSU regions of E. pakistanica supports its novel identity within the genus Erysiphe (Sect. Uncinula). A comprehensive description along with photographs and phylograms to show its exact position and a comparison with closely related taxa is provided.

Biogeography pattern of the marine angiosperm Cymodocea nodosa in the eastern Mediterranean Sea related to the quaternary climatic changes.

We investigated the population dynamics of a highly clonal marine angiosperm, Cymodocea nodosa, in the eastern Mediterranean Sea, to identify the historical dynamics, demography, and connectivity of the species in the area. Eighteen microsatellite loci were used in conjunction with coalescent methods to investigate the genetic structure and demographic history of C. nodosa meadows. Approximate Bayesian computation (ABC) modeling was used to examine the pattern of divergence over time in the context of environmental change over the course of the Quaternary period. ABC analysis revealed an initial split of the C. nodosa populations between the north‐western, northern, and north‐eastern Aegean Sea during the Pleistocene epoch, followed by a more recent divergence of the north‐western population and the central‐western part of the Aegean Sea. According to the results, the most parsimonious historical scenario is that of a pervasive genetic signature of the effects of the drop in sea level during the Pleistocene epoch. This scenario supports the isolation of the north‐western, north, and north‐eastern area, and the subsequent recolonization after post‐glaciation sea level rise that may explain the north‐western differentiation as well present‐day detected dispersion of C. nodosa.

Regional frequency analysis of drought severity and duration in Karkheh River Basin, Iran using univariate L-moments method.

Drought is one of the natural disasters that causes a great damage to human life and natural ecosystems. The main differences are in the gradual effect of drought over a relatively long period, impossibility of accurately determining time of the beginning and end of drought, and geographical extent of the associated effects. On the other hand, lack of a universally accepted definition of drought has added to the complexity of this phenomenon. In the last decade, due to increasing frequency of drought in Iran and reduction of water resources, its consequences have become apparent and have caused problems for planners and managers. So in this research, regional frequency analysis using L-moments methods was performed to investigate severity and duration of Standardized Precipitation Index (SPI), Standardized Evapotranspiration Index (SEI), Standardized Runoff Index (SRI), and Standardized Soil Moisture Index (SSI) and to study of meteorological, agricultural, and hydrological droughts in Karkheh River Basin in Iran. Using K-means clustering method, basin was divided into four homogeneous areas. Uncoordinated stations in each cluster were removed. The best regional distribution function was selected for each homogeneous region, and it was found that Pearson type (3) has the highest fit on the data set in the basin. Based on Hosking and Wallis heterogeneity test, Karkheh Basin with H1 < 1 was identified as acceptable homogeneous in all clusters. The results showed that hydrological drought occurs with a very short time delay in Karkheh River Basin after the meteorological drought, and two indicators show meteorological and hydrological drought conditions well. Agricultural drought occurs after meteorological and hydrological drought, respectively, and its severity and duration are less than the other indicators. Meteorological, hydrological, and agricultural droughts do not occur at the same time in all of the years. In general, the SPI drought index shows the most severe droughts compared with the other three indices. By this way, in 5- to 20-year return period with severity of 3SPI and in 20- to 100-year return period with severity of 7SPI, region IV or the western and northwestern areas of the basin has been affected by severe meteorological drought. By using the regional standardized quantities, it is possible to estimate the probability of drought in any part of the catchment that does not have sufficient data for hydrological studies.

Light absorption properties of black and brown carbon in winter over the North China Plain: Impacts of regional biomass burning

Biomass burning (BB) is an important source of brown carbon (BrC) and black carbon (BC), which are two key highly absorbent substances in atmospheric particles and can have a substantial positive impact on the climate radiative forcing. This study presents the light absorption properties of BC and BrC in PM2.5 during the winter in Beijing, with a discussion on the regional transportation of the light absorption of BC and BrC. Relatively high levels of the light absorption coefficient (Absλ) of BC, BrC, and the chemical compounds were found during haze episodes. The average AbsBC at λ = 880 and AbsBrC at λ = 370 during the haze period were as high as 4.4 and 2.9 times higher than those during the clean periods. The biomass burning tracer levoglucosan was significantly correlated with AbsBC880 (R2 = 0.53, P < 0.001), AbsBrC370 (R2 = 0.47, P < 0.001) and AbsBC(BB) (R2 = 0.69, P < 0.001). The average contributions of biomass burning to organic carbon (OC) and AbsBC were 33% and 48%, respectively, indicating that biomass burning was an important source of light-absorbing substances in the atmosphere. Concentration-weighted trajectory (CWT) analyses using TrajStat software also demonstrated that regional transport of biomass burning emissions from the northwestern and southwestern areas, which cover the intense fire spots from VIIRS, had a considerable influence on the light absorption properties of PM2.5 and even haze formation in Beijing during the winter.

Distribution Characteristics of the Deep Geothermal Field in the Sichuan Basin and its Main Controlling Factors

Geothermal energy and petroleum are two resources that coexist in sedimentary basins, and both of them are closely related to temperature. Based on the surface heat flow and the rock thermophysical properties, the deep geothermal field was calculated, then temperature distribution characteristics and the primary influencing factors on the geothermal state were discussed. The temperature distribution map of the Sichuan Basin for depths of 3,000–9,000 m presented the central and southern areas are characterized by relatively higher temperatures while the northwestern and northeastern areas are characterized by lower temperatures. Strata temperature in the central and southern areas exceeded 150°C as the burial depth reached 5,000 m. At the depth of 7,000 m, the temperatures in the central and southern areas were above 180°C, which is the threshold temperature for hot dry rock (HDR), while the temperatures in the northwestern and northeastern areas were below 160°C, which is close to the lower limit for oil crude oil cracking. The central and southern areas are favorite zones for the exploration of geothermal energy, conversely, the relatively lower temperatures in the northern, northwestern, and eastern areas are conducive to the presence of oil and gas. The unevenly distribution of geothermal field were controlled by the thicknesses of sedimentary layer and the crust, which indicates the lithosphere flexure and thickening caused by compression and depression, rapid deposition in the foreland depressions. The results can provide geothermal understandings for the exploration and development of the petroleum and geothermal resources and could serve as a reference for geodynamic studies in the Sichuan Basin.