Reservoir characteristics and formation model of Upper Carboniferous bauxite series in eastern Ordos Basin,NW China

Through core observation,thin section identification,X-ray diffraction analysis,scanning electron microscopy,and low-temperature nitrogen adsorption and isothermal adsorption experiments,the lithology and pore characteristics of the Upper Carboniferous bauxite series in eastern Ordos Basin were analyzed to reveal the formation and evolution process of the bauxite reservoirs.A petrological nomenclature and classification scheme for bauxitic rocks based on three units(aluminum hydroxides,iron minerals and clay minerals)is proposed.It is found that bauxitic mudstone is in the form of dense massive and clastic structures,while the(clayey)bauxite is of dense massive,pisolite,oolite,porous soil and clastic structures.Both bauxitic mudstone and bauxite reservoirs develop dissolution pores,intercrystalline pores,and microfractures as the dominant gas storage space,with the porosity less than 10% and mesopores in dominance.The bauxite series in the North China Craton can be divided into five sections,i.e.,ferrilite(Shanxi-style iron ore,section A),bauxitic mudstone(section B),bauxite(section C),bauxite mudstone(debris-containing,section D)and dark mudstone-coal section(section E).The burrow/funnel filling,lenticular,layered/massive bauxite deposits occur separately in the karst platforms,gentle slopes and low-lying areas.The karst platforms and gentle slopes are conducive to surface water leaching,with strong karstification,well-developed pores,large reservoir thickness and good physical properties,but poor strata continuity.The low-lying areas have poor physical properties but relatively continuous and stable reservoirs.The gas enrichment in bauxites is jointly controlled by source rock,reservoir rock and fractures.This recognition provides geological basis for the exploration and development of natural gas in the Upper Carboniferous in the study area and similar bauxite systems.

Spatio-Temporal Characteristics of Heavy Precipitation Forecasts from ECMWF in Eastern China

This study examines the spatio-temporal characteristics of heavy precipitation forecasts in eastern China from the European Centre for Medium-Range Weather Forecasts(ECMWF) using the time-domain version of the Method for Object-based Diagnostic Evaluation(MODE-TD). A total of 23 heavy rainfall cases occurring between 2018 and 2021 are selected for analysis. Using Typhoon “Rumbia” as a case study, the paper illustrates how the MODE-TD method assesses the overall simulation capability of models for the life history of precipitation systems. The results of multiple tests with different parameter configurations reveal that the model underestimates the number of objects’ forecasted precipitation tracks, particularly at smaller radii. Additionally, the analysis based on centroid offset and area ratio tests for different classified precipitation objects indicates that the model performs better in predicting large-area, fast-moving, and longlifespan precipitation objects. Conversely, it tends to have less accurate predictions for small-area, slow-moving, and shortlifespan precipitation objects. In terms of temporal characteristics, the model overestimates the forecasted movement speed for precipitation objects with small-area, slow movement, or both long and short lifespans while underestimating it for precipitation with fast movement. In terms of temporal characteristics, the model tends to overestimate the forecasted movement speed for precipitation objects with small-area, slow movement, or both long and short lifespans while underestimating it for precipitation with fast movement. Overall, the model provides more accurate predictions for the duration and dissipation of precipitation objects with large-area or long-lifespan(such as typhoon precipitation) while having large prediction errors for precipitation objects with small-area or short-lifespan. Furthermore, the model’s simulation results regarding the generation of precipitation objects show that it performs relatively well in simulating the generation of large-area and fast-moving precipitation objects. However, there are significant differences in the forecasted generation of small-area and slow-moving precipitation objects after 9 hours.

Rheological Evidence of the Lithospheric Destruction of the Eastern Block of the North China Craton

The Eastern Block of the North China Craton(NCC)(Fig.1)has undergone severe lithospheric destruction,with crustal thinning down to 100 km depth(Chen et al.,2009),contrasting sharply with the stable Kalahari and Rae cratons.However,there remains controversy over the destruction pattern(e.g.,Zhu et al.,2017).During the Early Mesozoic,crustal thickening occurred in the Xuhuai and Qinling orogens,followed by lithospheric delamination leading to crustal thinning(Chen et al.,2023).The middle and upper crustal thinning in the Yanshan and Taihang uplifts was induced by mafic magma underplating(Ji et al.,2009).

Different ENSO Impacts on Eastern China Precipitation Patterns in Early and Late Winter Associated with Seasonally-Varying Kuroshio Anticyclonic Anomalies

Winter precipitation over eastern China displays remarkable interannual variability,which has been suggested to be closely related to El Niño-Southern Oscillation(ENSO).This study finds that ENSO impacts on eastern China precipitation patterns exhibit obvious differences in early(November-December)and late(January-February)winter.In early winter,precipitation anomalies associated with ENSO are characterized by a monopole spatial distribution over eastern China.In contrast,the precipitation anomaly pattern in late winter remarkably changes,manifesting as a dipole spatial distribution.The noteworthy change in precipitation responses from early to late winter can be largely attributed to the seasonally varying Kuroshio anticyclonic anomalies.During the early winter of El Niño years,anticyclonic circulation anomalies appear both over the Philippine Sea and Kuroshio region,enhancing water vapor transport to the entirety of eastern China,thus contributing to more precipitation there.During the late winter of El Niño years,the anticyclone over the Philippine Sea is further strengthened,while the one over the Kuroshio dissipates,which could result in differing water vapor transport between northern and southern parts of eastern China and thus a dipole precipitation distribution.Roughly the opposite anomalies of circulation and precipitation are displayed during La Niña winters.Further analysis suggests that the seasonally-varying Kuroshio anticyclonic anomalies are possibly related to the enhancement of ENSO-related tropical central-eastern Pacific convection from early to late winter.These results have important implications for the seasonal-tointerannual predictability of winter precipitation over eastern China.

The Discovery of the Banda Bend,a>2000 km-wide Tectonically Formed Extensional Bend in Eastern Indonesia,Southeast Asia

The Weber Deep represents a widespread crustal extension system in eastern Indonesia with a huge submarine normal fault system,the Banda Detachment,related to the slab rollback tectonic model(Spakman and Hall,2010;Cummins et al.,2020).However,the cause of tectonic extension remains debated(e.g.,Audley-Charles et al.,1972;McCaffrey,1988;Das,2004;Spakman and Hall,2010;Pownall et al.,2013;Cummins et al.,2020;Hutchings and Mooney,2021;Shah et al.,2023).

Dynamic Characteristics of the Long Runout Rock-ice Avalanche at High Altitude——A Case from the Zelongnong Basin,Eastern Himalayan Syntaxis,China

Rock-ice avalanches have frequently occurred in the Eastern Himalayan Syntaxis region due to climate change and active tectonic movements.These events commonly trigger catastrophic geohazard chains,including debris flows,river blockages,and floods.This study focuses on the Zelongnong Basin,analyzing the geomorphic and dynamic characteristics of high-altitude disasters.The basin exhibits typical vertical zonation,with disaster sources initiating at elevations exceeding 4000 m and runout distances reaching up to 10 km.The disaster chain movement involves complex dynamic effects,including impact disintegration,soil-rock mixture arching,dynamic erosion,and debris deposition,enhancing understanding of the flow behavior and dynamic characteristics of rock-ice avalanches.The presence of ice significantly increases mobility due to lubrication and frictional melting.In the disaster event of September 10,2020,the maximum flow velocity and thickness reached 40 m/s and 43 m,respectively.Furthermore,continuous deformation of the Zelongnong glacier moraine was observed,with maximum cumulative deformations of 44.68 m in the distance direction and 25.96 m in the azimuth direction from March 25,2022,to August 25,2022.In the future,the risk of rock-ice avalanches in the Eastern Himalayan Syntaxis region will remain extremely high,necessitating a focus on early warning and risk mitigation strategies for such basin disasters.

Origin and geochemical characteristics of beryllium mineralization in the Zabara-Wadi El Gemal region,South Eastern Desert,Egypt

Beryl is the commercial source of beryllium and several varieties of it are valued as a gemstone.To contribute to understanding the mechanism of beryl formation,we carried out detailed geological,petrographical,and geochemical investigations on beryl mineralization occurrences in the Zabara-Wadi El Gemal(Z-WG)region.This region is an NW-SE trending tract that includes six berylhosting areas.The green gem variety of beryl(emerald)is restricted to phlogopite schist,pegmatite,and quartz veins.Prismatic hexagonal emerald crystals are well-developed in phlogopite schist and pegmatite.The gem variety emerald examined is sodic and Cr-dominant.It contains high concentrations of chromophore transition elements ordering Cr(up to 1511 ppm)>V(up to 242 ppm)>Sc(up to 245 ppm),giving rise to its vivid green color,refl ecting mafic-ultramafic source contribution.Among the investigated emeralds,the Sikait area contains the highest BeO(av.10.76wt.%)concentration.The compositional variability of emeralds is most likely attributed to the contribution from the host rocks.This is revealed by the examined emerald mineralization,for instance;the Abu Rusheid area(one of the best areas exposing rare metal-bearing granitoids)possesses the highest average of trace and REEs concentrations.In contrast,Um Kabu emerald has the highest contents of Co(av.20 ppm),Ni(av.299 ppm),MgO(av.8.2wt.%),Fe_(2)O_(3)(av.3.12wt.%),and CaO(avg.3.4wt.%)relative to other areas,which may be linked to contribution of ultramafic rocks exposed there.The proposed mechanism we suggest for emerald genesis is metasomatic interaction between felsic intrusions,that are enriched with K,Na,Be,Li,and B,with mafic-ultramafic rocks that are enriched in Cr,V,Mg,Fe,and Ca.This interaction is marked by the formation of phlogopite schist,the growth of emerald crystals,and desilicated pegmatite.

The nature and movement of thrusts in the eastern Iranian orogen:Sechengi Area on the northern border of Lut and Sistan

The eastern Iranian range,known as the Sistan suture zone in the past,has recently been identified as the Sistan orogen.This Paleogene orogeny is located between the Lut and Afghan microcontinents.The structural analysis shows that most of the thrusts dip towards the NW so that the Permo-Triassic sediments and Jurassic micro-diorites of the Lut Block overthrusted over the younger rocks.Structural studies show that the tectonic vergence was from the NW to the SE of the Sechengi area in the NW part of Sistan orogen.We recognized three deformation phases in eastern Iran.The first N-S deformation event(D1)resulted in the formation of tight E-W folds(F1)and associated cleavages(S1).The second E-W deformation event(D2),which occurred in the late Paleogene led to the bending of older structures,including the axial plane of the first-generation folds giving them a new northwest direction(F2).Additionally,the ramp of the first-phase thrusts(striking E-W)was reactivated,acquiring a new NNW orientation and exhibiting SSE tectonic vergence.The third deformation event(D3)resulted in the formation of NNE and WNW conjugate faults in eastern Iran.Such consecutive deformation events perpendicular to each other are inconsistent with the models of simple linear orogen presented for eastern Iran(i.e.rifting of eastern Iran continental crust and subsequence linear collision)and seem more consistent with the buckling orogeny(Orocline).

Texture and Geochemistry of Multi-stage Hydrothermal Scheelite in the Mamupu Cu-Au-Mo(-W)Deposit,Eastern Tibet:Implications for Tungsten Mineralization in the Yulong Belt

Multistage tungsten mineralization was recently discovered in the Mamupu copper-polymetallic deposit in the southern Yulong porphyry copper belt(YPCB),Tibet.This study reports the results of cathodoluminescence,trace element and Sr isotope analyses of Mamupu scheelite samples,undertaken in order to better constrain the mechanism of W mineralization and the sources of the ore-forming fluids.Three different types of scheelite are identified in the Mamupu deposit:scheelite A(Sch A)mainly occurs in breccias during the prograde stage,scheelite B(Sch B)forms in the chlorite-epidote alteration zone in the retrograde stage,while scheelite C(Sch C)occurs in distal quartz sulfide veins.The extremely high Mo content and negative Eu anomaly in Sch A represent high oxygen fugacity in the prograde stage.Compared with ore-related porphyries,Sch A has a similar REE pattern,but with higher ΣREE,more depleted HREE and slightly lower(^(87)Sr/^(86)Sr)i ratios.These features suggest that Sch A is genetically related to ore-related porphyries,but extensive interaction with carbonate surrounding rocks affects the final REE and Sr isotopic composition.Sch B shows dark(Sch B-I)and light(Sch B-II)domains under CL imaging.From Sch B-I to Sch B-II,LREEs are gradually depleted,with MREEs being gradually enriched.Sch C has the highest LREE/HREE ratio,which indicates that it inherited the geochemical characteristics of fluids after the precipitation of HREE-rich minerals,such as diopside and garnet,in the early prograde stage.The Mo content in Sch B and Sch C gradually decreased,indicating that the oxygen fugacity of the fluids changed from oxidative in the early stages to reductive in the later,the turbulent Eu anomaly in Sch B and Sch C indicating that the Eu anomaly in the Mamupu scheelite is not solely controlled by oxygen fugacity.The extensive interaction of magmatic-hydrothermal fluids and carbonate provides the necessary Ca^(2+)for the precipitation of scheelite in the Mamupu deposit.

Geochemistry of island arc assemblage in the Eastern Desert of Egypt and the role of Pan-African magmatism in crustal growth of the Arabian–Nubian Shield:A review

Neoproterozoic island arc assemblage of the Arabian–Nubian Shield(ANS)in the Eastern Desert(ED)of Egypt comprises juvenile suites of metavolcanics(MV),large amounts of meta-sedimentary rocks(MS),and voluminous metagabbros-diorites(MGD)and syn-tectonic intrusions of older granitoids(OG).We report here the updates of these four rock units in terms of classification,distribution,chemical characteristics,geodynamic evolution,metamorphism,and ages.In addition,we discuss these integrated data to elucidate a reasonable and reliable model for crustal evolution in the ANS.The main features of these rock units indicate their relation to each other and the geodynamic environment dominated by early immature oceanic island arcs to primitive continental arcs.Integrated information of the island arc metavolcanic and plutonic rocks(gabbros,diorites,tonalites,and granodiorites)furnish evidence of the genetic relationships.These include proximity and a coeval nature in the field;all protolith magmas are subalkaline in nature following calc-alkaline series with minor tholeiitic affinities;common geochemical signature of the arc rocks and subduction-related magmatism;their similar enrichment in LREEs;and similar major element compositions with mafic melts derived from metasomatized mantle wedge.The volcano-sedimentary and the OG rocks underwent multiphase deformation events whereas the MGD complexes deformed slightly.Based on the magmatic,sedimentological,and metamorphic evolutions constrained by geochronological data as well as the progressive evolutionary trend from extensional to compressional regimes,a possible gradual decrease in the subducted slab dip angle is the most infl uential in any geodynamic model for arc assemblage in the ED of Egypt.

Decadal Changes in Dry and Wet Heatwaves in Eastern China:Spatial Patterns and Risk Assessment

Under global warming,understanding the long-term variation in different types of heatwaves is vital for China’s preparedness against escalating heat stress.This study investigates dry and wet heatwave shifts in eastern China over recent decades.Spatial trend analysis displays pronounced warming in inland midlatitudes and the Yangtze River Valley,with increased humidity in coastal regions.EOF results indicate intensifying dry heatwaves in northern China,while the Yangtze River Valley sees more frequent dry heatwaves.On the other hand,Indochina and regions north of 25°N also experience intensified wet heatwaves,corresponding to regional humidity increases.Composite analysis is conducted based on different situations:strong,frequent dry or wet heatwaves.Strong dry heatwaves are influenced by anticyclonic circulations over northern China,accompanied by warming SST anomalies around the coastal midlatitudes of the western North Pacific(WNP).Frequent dry heatwaves are related to strong subsidence along with a strengthened subtropical high over the WNP.Strong and frequent wet heatwaves show an intensified Okhotsk high at higher latitudes in the lower troposphere,and a negative circumglobal teleconnection wave train pattern in the upper troposphere.Decaying El Niño SST patterns are observed in two kinds of wet heatwave and frequent dry heatwave years.Risk analysis indicates that El Niño events heighten the likelihood of these heatwaves in regions most at risk.As global warming continues,adapting and implementing mitigation strategies toward extreme heatwaves becomes crucial,especially for the aforementioned regions under significant heat stress.

Observation of Low-Level Jets in the Eastern Tropical Indian Ocean Based on Shipborne Coherent Doppler Lidar

In contrast to the Pacific and Atlantic Oceans,the Indian Ocean has lacked in-situ observations of wind profiles over open sea areas for decades.In 2021,a shipborne coherent Doppler lidar(CDL)was used to observe in-situ wind profiles in the eastern tropical Indian Ocean.This equipment successfully captured low-level jets(LLJs)in the region,and their characteristics were thoroughly analyzed.Results reveal that the observed wind speed of LLJs in the eastern Indian Ocean ranges from 6 m s^(-1) to 10 m s^(-1) during the boreal winter and spring seasons,showing a height range of 0.6 to 1 km and two peak times at 0800 and 2000 UTC.This wind shear is weaker than that in land or offshore areas,ranging from 0 s^(-1) to 0.006 s^(-1).Moreover,the accuracy of the CDL data is compared to that of ERA5 data in the study area.The results indicate that the zonal wind from ERA5 data significantly deviated from the CDL measurement data,and the overall ERA5 data are substantially weaker than the in-situ observations.Notably,ERA5 underestimates northwestward LLJs.

Mineralogy and geochemistry of trachytic rocks from the Lichi Volcanics, Eastern Himalaya: insights into the Kerguelen mantle plume activity in the Eastern Himalayan Region

The Lichi volcanics are a suite of mafic-intermediate-felsic rocks and are considered coeval with the Abor volcanics(~132 Ma) of the Siang window in the Eastern Himalaya. Here, we present the first report of trachytic rocks from the Lichi volcanics, which are exposed in the Ranga valley, along the Kimin-Yazali road section in the Eastern Himalayan Region, Northeast India. The trachytes occur in close association with sandstones of the Gondwana Group of rocks and are characterised based on field, petrographical, and geochemical investigations.These fine-grained trachytes are composed of alkali feldspar, biotite, plagioclase, sodic-amphibole, apatite, illmenite, and titanite. The REE profiles of the evolved trachytic rocks(higher SiO_(2)content) display fractionated trends. The fractionation of accessory mineral phases, like apatite and titanite, was possibly responsible for the strongly fractionated REE patterns of the evolved samples.The trachytic rocks demonstrate high apatite saturation temperatures of 988 ± 14 ℃(1σ, n = 8). The Aluminium Saturation Index(< 1.1) and binary discrimination diagrams of these peralkaline trachytes define their affinity with A-type granitoids. Elemental ratios like Y/Nb, Nb/U,and Ce/Pb signify that the Lichi trachytes are differentiated products of mantle-derived ocean island basalts. Trace elemental discrimination diagrams Th/Yb versus Nb/Yb, Y versus Nb, and Y + Nb versus Rb reflect a within-plate tectonic regime for the trachytes. From the results presented in this work, we infer that the development of rifting events during the breakup of eastern Gondwana due to the onset of Kerguelen plume activity further led to underplating of basic magma in lower crustal levels. These parental basaltic magmas underwent fractionation processes forming differentiated trachyandesites and trachytes.Taking into consideration the similarities recorded between the Lichi volcanics and Abor volcanics, this study supports the idea that Kerguelen plume activities resulted in the emplacement of these volcanics in the Eastern Himalayas.

Trend of Storm Surge Induced by Typical Landfall Super Typhoons During 1975–2021 in the Eastern China Sea

Climate change affects the activity of global and regional tropical cyclones(TCs).Among all TCs,typical super typhoons(STYs)are particularly devastating because they maintain their intensity when landing on the coast and thus cause casualties,economic losses,and environmental damage.Using a 3D tidal model,we reconstructed the typhoon(TY)wind field to simulate the storm surge induced by typical STYs.The TY activity was then analyzed using historical data.Results showed a downtrend of varying degrees in the annual frequency of STYs and TCs in the Western North Pacific(WNP)Basin,with a significant trend change observed for TCs from 1949 to 2021.A large difference in the interannual change in frequency was found between STYs and TCs in the WNP and Eastern China Sea(ECS).Along the coast of EC,the frequency of landfall TCs showed a weak downtrend,and the typical STYs showed reverse micro growth with peak activity in August.Zhejiang,Fujian,and Taiwan were highly vulnerable to the frontal hits of typical STYs.Affected by climate change,the average lifetime maximum intensity(LMI)locations and landfall locations of typical STYs in the ECS basin showed a significant poleward migration trend.In addition,the annual average LMI and accumulated cyclone energy showed an uptrend,indicating the increasing severity of the disaster risk.Affected by the typical STY activity in the ECS,the maximum storm surge area also showed poleward migration,and the coast of North China faced potential growth in high storm surge risks.

Spatial distribution characteristics of climate-induced landslides in the Eastern Himalayas

Climate warming is constantly causing hydro-meteorological perturbations,especially in high-altitude mountainous regions,which lead to the occurrences of landslides.The impact of climatic variables(i.e.,precipitation and temperature)on the distribution of landslides in the eastern regions of the Himalayas is poorly understood.To address this,the current study analyzes the relationship between the spatial distribution of landslide characteristics and climatic variables from 2013 to 2021.Google Earth Engine(GEE)was employed to make landslide inventories using satellite data.The results show that 2163,6927,and 9601 landslides were heterogeneously distributed across the study area in 2013,2017,and 2021,respectively.The maximum annual temperature was positively correlated with the distribution of landslides,whereas precipitation was found to have a non-significant impact on the landslide distribution.Spatially,most of the landslides occurred in areas with maximum annual precipitation ranging from 800 to 1600 mm and maximum annual temperature above 15℃.However,in certain regions,earthquake disruptions marginally affected the occurrence of landslides.Landslides were highly distributed in areas with elevations ranging between 3000 and 5000 m above sea level,and many landslides occurred near the lower permafrost limit and close to glaciers.The latter indicates that temperature change-induced freeze-thaw action influences landslides in the region.Temperature changes have shown a positive correlation with the number of landslides within elevations,indicating that temperature affects their spatial distribution.Various climate projections suggest that the region will experience further warming,which will increase the likelihood of landslides in the future.Thus,it is crucial to enhance ground observation capabilities and climate datasets to effectively monitor and mitigate landslide risks.

April-September minimum temperature reconstruction based on Sabina tibetica ring-width chronology in the central eastern Tibetan Plateau,China

Minimum temperatures have remarkable impacts on tree growth at high-elevation sites on the Tibetan Plateau,but the shortage of long-term and high-resolution paleoclimate records inhibits understanding of recent minimum temperature anomalies.In this study,a warm season(April–September)reconstruction is presented for the past 467 years(1550–2016)based on Sabina tibetica ring-width chronology on the Lianbaoyeze Mountain of the central eastern Tibetan Plateau.Eight warm periods and eight cold periods were identified.Long-term minimum temperature variations revealed a high degree of coherence with nearby reconstructions.Spatial correlations between our reconstruction and global sea surface temperatures suggest that warm season minimum temperature anomalies in the central eastern Tibetan Plateau were strongly influenced by large-scale ocean atmospheric circulations,such as the El Ni?o-Southern Oscillation and the Atlantic Multidecadal Oscillation.

Public-private-partnership needs under the National Tuberculosis Elimination Program in an Eastern Indian state

Eliminating tuberculosis(TB)is among India's top public health priorities[1].Despite the considerable progress in providing quality TB care services,the Global TB report-2022 reveals that India is amongst the eight high TB burden countries that contributed to more than two-thirds(68.3%)of the global TB cases[2].To strengthen and aid the TB elimination efforts by 2025,five years ahead of the sustainable development goal target,the Government of India,under the program,promotes intersectoral convergence with various public sector departments and the private sector.The national multisectoral action framework for TB-free India promotes private-private or public-private partnerships for sustainable and impactful Corporate Social Responsibility initiatives[3].

Mechanism of Diabatic Heating on Precipitation and the Track of a Tibetan Plateau Vortex over the Eastern Slope of the Tibetan Plateau

Existing studies contend that latent heating(LH)will replace sensible heating(SH)to become the dominant factor affecting the development of the Tibetan Plateau vortex(TPV)after it moves off the Tibetan Plateau(TP).However,in the process of the TPV moving off the TP requires that the airmass traverse the eastern slope of the Tibetan Plateau(ESTP)where the topography and diabatic heating(DH)conditions rapidly change.How LH gradually replaces SH to become the dominant factor in the development of the TPV over the ESTP is still not very clear.In this paper,an analysis of a typical case of a TPV with a long life history over the ESTP is performed by using multi-sourced meteorological data and model simulations.The results show that SH from the TP surface can change the TPV-associated precipitation distribution by temperature advection after the TPV moves off the TP.The LH can then directly promote the development of the TPV and has a certain guiding effect on the track of the TPV.The SH can control the active area of LH by changing the falling area of the TPV-associated precipitation,so it still plays a key role in the development and tracking of the TPV even though it has moved out of the main body of the TP.

Groundwater Modelling of Motloutse Alluvial Aquifer, Eastern Botswana

The potential groundwater reserve in alluvial aquifers and sandy river beds has not been well studied, and yet their benefit in meeting rural water supply demands cannot be underestimated. A three-dimensional steady-state finite difference numerical groundwater flow model was used to assess the groundwater resource potential on a one-kilometre river stretch scale along the Motloutse River catchment in eastern Botswana. The model area is a single-layer unconfined aquifer system. A uniform grid was laid over this phreatic aquifer, and an overall size of 50 columns x 54 rows was developed. The model yielded calibrated K values of 145 m/day and 11 m/day for the riverbed and riverbank sediments, respectively, and calibrated recharge and evaporation of 172 mm/yr and 120 mm/yr, respectively. A sustainable groundwater yield of 120 m3/day with the potential to irrigate an area of 2.4 hectares was determined. The result also shows that the Motloutse alluvial aquifer yields a safe yield of 29,400 m3 for a kilometre of river stretch.

Integrity and Size of Green Spaces Are Critical for the Functional Di-versity of Birds:Evidence from the Eastern and Northwestern Regions of China

Urbanization often changes bird species richness and affects the functional diversity.Therefore,understanding these changes helps city planners improve green space design and land use planning.Our study used multiple datasets to explore the effects of land-scape patterns and natural environments on the functional diversity of birds in urban parks and campuses in the eastern and northwest-ern regions of China.Firstly,we used the data to calculate birds of the functional richness(FRic),functional evenness(FEve),and func-tional divergence(FDiv)of 68 urban spaces in the eastern and northwestern regions of China.Further,we established generalized linear models of natural factors,human factors,and functional diversity.Results showed more bird species with unique traits were in the north-western region.This may be because the earlier urbanization in the eastern region filtered out urban-sensitive species,leaving behind urban adapters.Moreover,we found that the fractal dimension index was the most significant positive factor of FRic in the eastern re-gion but the most significant negative factor of FDiv.Elevation was the most significant negative influence factor of FEve in the eastern region,but it was the most potent positive influence factor of FRic in the northwestern region.Population density had a significant posit-ive effect on FDiv in the northwestern region.However,green space areas significantly negatively impacted FEve in the northwestern region.In addition,birds in parks in both regions had more functional traits than those on campuses,possibly because of the larger green space in parks,which may contain more fragments of native vegetation and reduce human interference.Our study suggests that pre-serving more original vegetation and reducing human disturbance in cities can increase the functional diversity of urban birds and im-prove urban ecosystem functions.