Northeastern Side Research Articles

Distinct patterns of sea surface temperature anomaly in the South Indian Ocean during austral autumn

A neural network-based cluster technique called self-organizing map (SOM) determines 12 distinguishable patterns derived from the sea surface temperature (SST) anomaly fields in the South Indian Ocean for 1901–2010 in austral autumn (March–May). Two out of twelve patterns (patterns 1 and 12) are characterized by a dipole pattern with opposite SST anomalies in the Southwest Indian Ocean and to its northeastern side, which is similar to the so-called Indian Ocean Subtropical Dipole (IOSD), and they are named as traditional IOSD (T-IOSD) in the present work. Patterns 2 and 11 show a similar dipole pattern of a northeast-southwest orientation, which can be significantly distinguished from T-IOSD due to their distinct location of action centers, amplitudes and evolution processes. These two patterns were called new IOSD (N-IOSD). For both positive and negative positive phase of T-IOSD, the anomalous dipole pattern is first observed near Madagascar in previous spring and it migrates eastward and forms the typical pattern of T-IOSD in early summer. Differently, for positive phase of N-IOSD, significant SST anomalies appear to the west of Australia continent at first in late spring, and a well-organized dipole pattern could not be observed until late summer, approximately one or two months later than the formation time of T-IOSD. The major asymmetry of N-IOSD characterizes one month later of the formation time for the negative phase of N-IOSD, compared with its positive phase. The possible mechanisms responsible for different evolution process of T-IOSD and N-IOSD events were examined. The results show that latent heat flux, not surprisingly, plays an essential role in the formation of both T-IOSD and N-IOSD. However, the contribution of meridional advection by anomalous oceanic current to the N-IOSD event is much more important than that to the T-IOSD.

Phytoplankton assemblage with relation to water quality in Turag River of Bangladesh

The study was performed to evaluate phytoplankton assemblage, physical and chemical characteristics of water, interrelationship between phytoplankton assemblage and physical/chemical characteristics of water and to evaluate water quality index during November, 2015 - September, 2016 for Turag River that is located on the north-eastern side of Dhaka city, Bangladesh. Water samples were collected during winter (November - January/2015-2016), summer (March-May/2016) and rainy season (July September/2016). During the study, the overall phytoplankton assemblage exhibited the following pattern: Bascillariophyceae (40.33%) > Chlorophyceae (32.90%) > Euglenophyceae (14.56%) > Cyanophyceae (12.20%). Fragillaria crotonensis, Navicula grimmei, Phacus circulatus, Euglena agilis, Chlorococcus minutum and Trachelomonas goossensii were dominant phytoplankton species. The average values of water temperature, total dissolved solids (TDS), electric conductivity (EC), pH, dissolved oxygen (DO), biological oxygen demand (BOD5), total nitrogen (TN) and dissolved phosphorus (DP) were 25.94°C, 273.46 mg L-1, 489.71µS cm-1, 6.81, 2.89 mg L-1, 3.85 mg L-1, 8.55 mg L-1 and 0.62 mg L-1, respectively. Euglenophyceae displayed significant negative correlation with DO in winter while TDS in rainy season. Chlorophyceae exhibited significant negative correlation with DP in rainy season. Shannon-Weaver’s (H') and Simpson’s (D) diversity indices ranged between 2.58-3.01 and 0.91-0.95, respectively. In summer, the value of H' (3.01) indicated slight pollution. In winter and rainy seasons, the values of H' were 2.58 and 2.98, respectively displaying light pollution in Turag river. Measured water quality index (WQI) values were 229.71, 171.23 and 74.18 in winter, summer and rainy season, respectively exhibiting that water was unsuitable for drinking purposes in winter and summer and also very poor water quality in rainy season, respectively. The implication of these findings can be used to monitor health of riverine ecosystems which provide ecosystem services for society.

Development of a Thornthwaite Moisture Index Map for Trinidad and Tobago

The Thornthwaite Moisture Index (TMI) has been traditionally used as a climatic index parameter to estimate annual moisture status of soils (deficit/surplus), primarily in the agricultural domain. Engineers have also adopted the TMI in efforts to estimate volume change potential in expansive clays, where seasonal (temporal) moisture changes can be correlated to soil matric suction and ultimately volume change via appropriate mechanistic models. In Trinidad and Tobago, approximately 60 % of the islands are covered with over-consolidated clays of medium to high plasticity. When combined with extreme variations in moisture status, these plastic clays have exhibited high volume change potential. This paper investigates the spatial distribution of this climatic index for Trinidad and Tobago, intending to develop an index map for the islands. Within the post-colonial era in Trinidad and Tobago (1962 ~ present), the availability of consistent climatic data is limited to just two recording stations within the islands. The Meteorological Services of Trinidad and Tobago (MET) manages both stations: Piarco, Trinidad and Crown Point, Tobago, where consistent data exists for 36 years (1981 ~ 2018). These two points and their limited data timeframe cannot support the development of a spatial TMI map for the islands. This research addresses this shortcoming by collecting and analysing historical climatic data collected at 28 stations over Trinidad and Tobago over the British Colonial era (1931 ~ 1964). These data are recorded in publications of the Land Capability Surveys of The Imperial College of Tropical Agriculture (ICTA). Data sets of monthly rainfall data from the historical and at present for the Piarco location showed strong statistical coherence, examined through a t-test. Having justified the historical data, TMI values are calculated at all locations. Using the calculated TMI values, a map was developed using the GIS software, Surfer, and interpolation method of Kriging. In Trinidad, the map indicates high TMI at the north-eastern side of the island, with a significant decrease going into the south-western side. Low TMI values are observed in the most western side of Trinidad indicating substantially long dry season period, during which the underlying expansive clay can experience significant shrinkage.

Challenges in public health facilities and services: evidence from a geographically isolated and disadvantaged area in the Philippines

# Background The study describes the conditions of public health sector in the Island Municipality of Jomalig, Quezon Province in Luzon, Philippines. Located at the far north-eastern side of the Quezon Province, Jomalig Island can be reached through a motor boat at around 4-5 hours (or more depending on the sea condition). Given the geographical disadvantage, challenges in economic and social services in the island are apparent. That includes deficiencies in basic public utility services such as water and electricity. The paper showcases a needs assessment on public health facilities and services in a far-flung municipality in the Philippines. This study examines the challenges in public health aspirations in a location considered to be a geographically isolated and disadvantaged area (GIDA). # Methods The study made use of key informant interviews (KIIs) among health professionals and village health workers in the island. Aside from the KIIs, the study included the World Health Organization's (WHO) tracer checklist on general readiness. The checklist was administered but in interview style. The participants were the public health staff in the island. The researcher was able to interview the health professionals (nurses and a midwife) manning the main public health facility in the island municipality while in the case of the other villages, health volunteers or the Barangay Health Worker (BHWs) were interviewed. # Results There are deficiencies in facilities, offered services and health staff. Deficiencies are seen too based on the domains under the WHO Tracer Checklist. Mortality and morbidity rates were not at alarming rate though reports of hypertension and diarrhea are common. The relatively complete health services are only available at the island's main health center yet unfortunately, some people who seek treatment and health care could not visit due to distance and the accompanying expenditures. Other factors affecting health status of the population include the reliance to faith healers (quack doctors or Albularyos) and the delay of parental reports of their health condition and the condition of their children, both of which result to the escalation of illness. Among others, challenges and aspirations of the island's public health sector include electric supply, better budgetary allocation for their facilities, and equipment and additional training for the barangay (village) health workers. # Conclusions Enduring the underfinanced and undermanned health facilities, the island's population also suffers the consequences on overall health owing to limited movements and communication due to the geographical characteristics of the municipality. Emergency boats per village, health education campaign that focuses on eliminating open defecation and reliance on quack doctors, stand-by generators for the health centers, and radio communication system are strongly recommended to mitigate the negative impacts of living within GIDA communities.

Isotope Characteristics (δ13C, δ18O) of Continental Carbonates from Permian‒Triassic Rocks in the Northeastern Russian Plate: Paleoclimatic and Biotic Reasons and Chemostratigraphy

Carbon and oxygen isotope compositions were determined in the pedogenic, sedimentary, and organogenic carbonates from Upper Permian (Vyatkian Stage) and Lower Triassic (Induan Stage) continental rocks in the northeastern Moscow Syneclise. Variations of δ18O (18.0 to 29.1‰ SMOW) and δ13C (‒8.8 to 0.7‰ PDB) in them could be provoked both by regional climatic fluctuations and by perturbation of the global carbon cycle at the Permian‒Triassic boundary. Decrease of δ18O in pedogenic carbonates at the top of the Vyatkian Stage was likely caused by cooling on the northeastern side of Pangea. The negative excursion of δ13C values at this stratigraphic level correlates with the analogous excursion recorded in marine carbonates of the Paleo- and Neotethys and corresponds to the end-Permian biotic event.

Significance of Wind-Pressure Relation during Bay of Bengal Cyclones

Cyclone is a natural disaster that blows Over Bay of Bengal (BoB) and makes masses of devastation. Assessment of its characteristics and prediction of its mobility are extremely difficult tasks. Wind and pressure are the most significant factors that decide cyclone genesis, propagation and intensity. Physical understanding of the relation between two significant parameters during cyclone is very complicated and is elusive through modelling and prediction. Data sourced from International Best Track Archive for Climate Stewardship (IBTrACS) were analyzed to know wind and pressure relation and cyclone tracking. Cyclone spatial wind pattern is determined using the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). Analysis shows that wind and pressure are related inversely and is complex in nature. Spatial analysis using MERRA-2 demonstrates asymmetric wind pattern. IBTrACS data (from 2005 to 2016) show the majority of the cyclone intensity is concentrated on north-eastern side of BoB which fact could be attributed to high subsurface heat storage. Inter comparison of different cyclones during the period 2005-2016 was also made and found in support of the wind pressure relation.

Multiyear variability of ecological-hygienic condition of the land: metals in soils of surroundings of the Astrakhan gas complex

There are presented the results of a 21-year-old (1991-2012) monitoring of Hg concentrations and amounts of metals, including heavy and toxic, Zc(MnCrVNiCoCuAgZnPbSnMo) in soils of the zone of the exposure to emissions from Astrakhan gas complex (AGK), working from 1987 within a radius of 50 km. On those criteria for the period over 1997-2012 there was revealed a steady deterioration of ecological-hygienic conditions of the lands in the control zone. The spatial variability of this condition is largely controlled by the dispersion of the emissions by the prevailing easterly and southeasterly winds. The content of Hg in 2007, remote from AGK by 15 km, increased by 6-8 times on the leeward north-west territories, where the accumulation of the toxicant was 2.5 times more pronounced than in the windward Eastern and North-Eastern side. The significant role in the deterioration of sanitary-ecological state of the territory of the sanitary protection zone when dealing with Hg-containing (70-100 mkg/kg) commodity grey belongs to reblowing of particles and their eolian spread from places of storage, loading and transportation. In separate halos the content of Hg in the soil has reached 285 mkg/kg and become closer to the "target" safe level (300 mkg/ kg), adopted in Western Europe (zone AGK-30 km). The total amount of metals as in the near (up to 5 km of sanitary protection), so far (5-50 km) zones as in background sites has increased steadily. By 2012 in some places, remoted up to 30 km from AGK there were fixed already hygienically dangerous levels of total metals accumulation (up to Zc =34)

Spatial distribution, variation and trend of five-day antecedent rainfall in Singapore

ABSTRACT This paper presents the spatial distribution, variation and trend of 5-day antecedent rainfall in Singapore based on rainfall data from 22 meteorological stations. The effect of climate was analyzed by dividing the study period into three decades i.e. Decade 1: 1982–1991, Decade 2: 1992–2001 and Decade 3: 2002–2011. Kriging interpolation was used for rainfall mapping. The results show that spatial distribution of 5-day antecedent rainfall does not coincide with that of the annual rainfall. The maximum annual rainfall occurred in the northwestern side of Singapore. On the other hand, the maximum 5-day antecedent rainfall occurred in the north and northeastern sides. The results of this study suggest that the climate change has increased the amount of 5-day antecedent rainfall quite significantly, i.e. from 420.5 (1987) to 592.9 mm (2006), thus affecting the vulnerability of the area with respect to rainfall-induced slope failure. The analyses also showed that most of slope failures were located in the north and northeast of Singapore between December and earlier March. More slope failures were observed in Decade 3 as compared to Decades 1 and 2. In other words, the analysis confirmed that 5-day antecedent rainfall had affected the slope stability in Singapore.

Population Census in Contemporary Bangladesh: A Multilateral Effort in an Ever-Changing Delta

Bangladesh, located in the Northeastern side of South Asia, is bordered by India to the west, north, and east and shares a small border with Myanmar in the hilly southeastern portion of the country...

Dynamic changes of groundwater storage and flows in a disturbed alpine peatland under variable climatic conditions

Climate change and gullies (and ditches) on peatlands are well known factors altering peat hydrology. Yet, exactly how this alteration emerges from interaction of these factors with groundwater dynamics is still not fully understood. In this study, we tackled this issue by coupling field measurement with model simulation using Visual MODFLOW. Groundwater processes and the associated water budget during five months of the wet season, 2017 were examined in the Zoige peatland, located on the northeastern side of Qinghai-Tibet Plateau, China with elevations of 3400–3900 m. Simulations were performed for a peatland area of 3.89 × 104 m2 and three sub-zones within it representing peatland with no gullies (NG), a deep gully cutting through the peat layer (CT), and a shallow gully whose bed is within the peat layer (NCT). Model input parameters were calibrated and validated using the field-measured data. Modeling outcomes led to water budget showing relative contributions of main hydrological pathways (MHPs) (i.e., precipitation (P), evapotranspiration (ET), gully, groundwater flow, and boundary) to changes of water storage in peats (ΔS). Although these MHPs varied differently during rain and inter-rain periods, ΔS values were mainly controlled by the oscillated trend of the difference between P and ET. Variations of MHPs caused by NCT and CT were secondary to those due to those of P and ET during the wet season referred to as the short-term climate change. Vertical groundwater (VGW) flows were strongly correlated with water table (WT) levels in both rain and inter-rain periods, but their directions had different patterns in the two periods. Horizontal groundwater (HGW) flows tended to move into the deep (CT) gully, while move from the shallow (NCT) gully to the neighbor peats during both periods. Since HGW flows were about ten times greater than VGW ones, their effect on ΔS was significant during the long dry season. This would lead to continuous loss of groundwater stored in peats, demonstrating the coupled effect of long-term climate change and gullies on ΔS. These findings underline the necessity of controlling gully development and avoiding ditch excavation in future Zoige peatland management practices.

Petrophysical analysis of well logs for reservoir evaluation: a case study of “Kadanwari” gas field, middle Indus basin, Pakistan

Our study focuses on the interpretation of wire-line logs to evaluate the hydrocarbons potential of sandstone reservoir in the Kadanwari gas field, Sindh, Pakistan. We have considered wire-line logs of four drilled wells (K-01, K-03, K-10, and K-11) in the research area and interpreted 13 reservoir zones. Analytical reservoir analysis includes the shale content (Vsh), effective porosity (Oeff), hydrocarbon and water saturation (Shc and Sw), and net pay thickness variations. Hydrocarbon-bearing zone characterized by high resistivity values, porosity high, permeability high, saturation of water low, and less Vsh suggest clean sand. The petrophysical analysis revealed the hydrocarbon potential of lower Goru sandstone packages at different levels (2886–3797 m). The petrophysical parameters of sub-reservoirs were carefully analyzed which are ranked as good quality sand reservoirs with average effective porosities ranging from 0.11–0.44%, average water saturation ranging from 0.18–0.45%, hydrocarbon saturation averaging between 0.59–0.86%, and permeability ranging from 10.539 to 477.76 m Darcy. Water saturation for heterogeneous shaly sand reservoirs was successfully tested by Indonesian model which suggests that Sw in each well is fewer than 60% therefore over all the region bearing good quality of hydrocarbon potential of the targeted formation and selected zones. The vertical and horizontal variations of reservoir parameters are studied through constructing the litho-saturation cross-plots and isoparametric maps of the petrophysical parameters, respectively. The isoparametric maps help to visualize the geographical distribution of reservoir configuration in the subsurface. The petrophysical estimates of this study appraise the national conventional fuel treasure of lower Goru formation in Kadanwari gas fields and suggest new prospects to drill more wells on the central portion of the southwestern part of the study area. The neighboring area to the south of Kadanwari-01 is economically viable for hydrocarbon exploration. The northeastern side of the study area is avoided due to the high concentration of water and excessive shale content.

Invasive Species Appear to Disrupt the Top-Down Control of Herbivory on a Mexican Oceanic Island

Oceanic islands are simplified ecosystems, which are very useful for understanding the processes related to the structuring of natural communities and for assessing cascade effects after perturbations. Socorro Island in the Pacific Ocean reaches up to 1040 m in elevation, and the northeastern side that faces trade winds is more humid than the leeward southwestern side. Apparently, the lack of freshwater throughout most of the island has prevented the spread of invasive cats and sheep to the north, but these species have severely impacted land bird communities on the southern side, where they have potentially disrupted functions such as the top-down control of herbivory. We tested the relative importance of bottom-up (soil and foliage nutrient availability) and top-down (predation of insect herbivores) drivers of herbivory in three endemic tree species. By experimentally excluding birds, we assessed changes in herbivory when top-down control was disrupted, and we also evaluated herbivore predation rates using artificial caterpillars. Our findings suggest that the herbivory patterns on Socorro Island are driven by the top-down control of herbivores by land birds, because their exclusion resulted in higher herbivory (12%) despite low nitrogen content (bottom-up control) of leaves on the north side, whereas the leaves were richer in nitrogen on the south side but no change in herbivory was observed when birds were excluded, and overall, herbivory was 30% higher than in the north, suggesting release of herbivores from top down control on the south side, probably due to effects of invasive predators (cats) or sheep, which may have reduced suitable bird habitats. A better understanding of how drivers of ecological interactions operate on Socorro Island may increase the likelihood of success of future restoration programs.

Interpretation of Geological Structures Hosting Potential Gold Deposits in the Konongo Gold Mine Using Airborne Magnetic, Electromagnetic and Radiometric Datasets

The renewed interest in the reactivation of the defunct National Konongo Gold Mine located in the Ashanti Greenstone Belt, calls for a further probe into its geology and the associated mineral hosting structures to discover its mineralization potential. In order to achieve this, airborne magnetic, radiometric and electromagnetic datasets were interpreted to determine the potential gold hosting features in the studied area. The results show the area to consist of the metasediment, the metavolcanic, Tartwaian Formation and their associated granitoids. Results also show that the Tarkwaian sediments, observed largely in the north-eastern side of the site; widen out substantially and truncate in the south. The analysis of the structure lineaments using a rose diagram reveals three main tectonic structures trending in N-S, NNW-SSE, and third the structure trending in the NNE-SSW to NE-SW directions in the area. The dominant structures in the area, form 90% of all the delineated structures and trend in the NE-SW and NNE-SSW direction with the remaining 10% trending in the N-S and NNW-SSE. These structures are associated with the major shear and fracture zones located mainly at the contact between the basin sediments and volcanic belt and also associated with the Tarkwaian Formation. The mapped potential gold mineralization zones located mainly at the contact between the metasediment and the metavolcanic units of the Birimian Supergroup, as well as the Tarkwaian Formation, were mapped by integrating the structures, alteration zones as well as the complex dyke systems. This paper delineates the prominent geological structures with the potential of hosting economic gold mineralization in and around the Konongo Gold Mine.

The repercussion of leachate from industries on water quality in jeedimetla village and its surroundings, medchal-malkajgiri district, telangana

Industries are the main resources for sustainable growth of the economy, but to allow waste water from industries create a lot of pollution in ground water and surface water. In this regard Jeedimetla industries association is one of the sources for the release of leachate. About 23 leachate samples are collected; they are filtered in canals, open ground, and lakes. By using UV spectrophotometer estimated the Arsenic, Nickel, Mercury and Nitrite, Nitrate mg/l. The toxic chemical percentage is very heavy, so most of the soil, water, and air is polluted. Thematic maps of toxic elements and physical parameters mainly concentrated in west side and Northeastern side of Jeedimetla village and its surroundings. The villages with good water quality resources available are Ramireddy Nagar, Maisammagudem and Bahadurpally, the main reason is industries far away from these areas. The villages with poor water quality are Dhulapally, Kaziguda, Jeedimetla, Chintal, Suraram and Apurupa colony. The water in the areas standard fall down due to industries drain on the surface. Arsenic values are high in Jeedimetla and Apurupa colony, it is very harmful to health. The government will take serious action immediately to stop drains of toxic element water or has to implement strict rules on the purification of water. Statistical analysis of the correlation matrix shows the relation between parameters EC, DO, Alkalinity, Fluoride, Nitrite, and Nitrate have positive relationships and remaining are negative. Positive relation is week 0.3 to <0.6 and strong relation is 0.6>.

A Highly Efficient Thermoelectric Module with Heat Storage Utilizing Sensible Heat for IoT Power Supply

In this study, we developed a thermoelectric generator unit (TEGU) for sensors measuring river water levels and set the power generation target needed for sensing and radio transmission to 38 J/day. To generate power by utilizing one-day temperature changes, it is most effective to arrange the heat storage on the cooling side of the TEGU. We investigated heat storage materials that would ensure the necessary power. In our simulation, we found the average yearly amount of power generated using a sensible heat (SH) material, e.g., alcohol solution, to be nearly twice that when using a latent heat (LH) material, e.g., paraffin. This is because LH is efficient only within a limited period when the melting point of the LH material is approximately equal to the average temperature of the heat source. Experimental results show the difference between the simulated and experimental values to be within 20% with respect to both LH and SH storage. As a demonstration project, we installed the developed TEGU on the northeastern side of the steel frame of a bridge in the city of Yokohama, and then measured the generated power from September 8, 2017. We recorded an average power generation of around 58.5 J/day, which is much larger than our target value of 38 J/day, and which remained almost constant from September 2017 to January 2018. In this paper, we present our design of the TEGU, our simulation and experimental results, and the power generation results when utilizing SH.

Eocene bryozoan assemblages from the La Meseta Formation of Seymour Island, Antarctica

Early to Late Eocene bryozoans from the La Meseta Formation of Seymour Island were collected at two localities within the Cucullaea I Allomember (Telm4 and Telm5) on the northwestern side of the island and in two localities within the Submeseta Allomember (Telm6 and Telm7) on the northeastern side. This fauna is represented by cyclostomes of the suborders Tubuliporina and Cerioporina and suborders of Neocheilostomata, among which nine species have been recognized. The following new species are introduced: Micropora nordenskjoeldi sp. nov., Lunulites marambionis sp. nov., Otionellina antarctica sp. nov. and Otionellina eocenica sp. nov. Some other taxa recognized in the studied material, such as Reticrescis plicatus , Uharella seymourensis and Celleporaria mesetaensis , were previously described from the lowermost (Telm1) or uppermost parts (Telm6–7), thus their stratigraphical ranges within the La Meseta Formation are extended. The diverse growth-forms of the bryozoans include a sole ball-shaped celleporiform colony and reticulated and bilamellar-foliaceous colony, as well as rich encrusting and free-living forms (so-called sand faunas), indicating the existence of locally restricted shallow-marine environments. This is particularly true in the middle and upper parts of the La Meseta Formation (Telm4–7). Reticulated, spheroidal and robust, branched colonies, which thrived in the environmental conditions of the lower part (Telm1), are represented only by a sparse bryozoan biota in the upper part of the La Meseta Formation. Lunulitiforms, such as Lunulites and Otionellina which are warm water, free-living bryozoans, dominate in the siliciclastic sediments of Telm5, but erect folded sheets forming a shell bed composed of ? Goodonia occur in Telm6–7. These three genera are recognized in Antarctica for the first time. The austral genus Otionellina has its earliest fossil record here, showing close biogeographical links with the Late Eocene–Miocene faunas of Australia and New Zealand. The taxonomic composition of the studied fauna together with their growth forms is a very good tool for reconstructing palaeoenvironmental conditions in the middle and upper parts (Telm4–7) of the La Meseta Formation, deposited during the Late Ypresian–Priabonian.

Seismic Evidence for Plume‐ and Craton‐Influenced Upper Mantle Structure Beneath the Northern Malawi Rift and the Rungwe Volcanic Province, East Africa

AbstractP and S wave tomographic models have been developed for the northern Malawi rift and adjacent Rungwe Volcanic Province (RVP) using data from the Study of Extension and maGmatism in Malawi aNd Tanzania project and data from previous networks in the study area. The main features of the models are a low‐velocity zone (LVZ) with δVp = ~−1.5–2.0% and δVs = ~−2–3% centered beneath the RVP, a lower‐amplitude LVZ (δVp = ~−1.0–1.3% and δVs = ~−0.7–1%) to the southeast of the RVP beneath the center and northeastern side of the northern Malawi rift, a shift of the lower‐amplitude anomaly at ~−10° to −11° to the west beneath the central basin and to the western side of the rift, and a fast anomaly at all depths beneath the Bangweulu Craton. The LVZ widens further at depths >~150–200 km and extends to the north beneath northwestern Malawi, wrapping around the fast anomaly beneath the craton. We attribute the LVZ beneath the RVP and the northern Malawi rift to the flow of warm, superplume mantle from the southwest, upwelling beneath and around the Bangweulu Craton lithosphere, consistent with high 3He/4He values from the RVP. The LVZ under the RVP and northern Malawi rift strongly indicates that the rifted lithosphere has been thermally perturbed. Given that volcanism in the RVP began about 10 million years earlier than the rift faulting, thermal and/or magmatic weakening of the lithosphere may have begun prior to the onset of rifting.

Impacts of Topography on Airflow and Precipitation in the Pyeongchang Area Seen from Multiple-Doppler Radar Observations

Abstract This study uses high-resolution radar and surface observations to investigate the finescale structural evolution of airflow and precipitation over complex terrain in the Pyeongchang area, South Korea. The Taebaek Mountain range (TMR) runs parallel to the northeastern coast of South Korea, with a perpendicular ridge known as the Pyeongchang branch (PCB). The objective of this study was to identify the mechanisms of wintertime precipitation over these topographic features during the passage of a low pressure system (LPS) through the southern Korean Peninsula. The analysis indicates that intense precipitation occurred over the southwestern and northeastern sides of the TMR during stage I but only over the northeastern side during stage II. The prevailing southwesterly winds were dominated by warm advection associated with the LPS over the PCB during stage I. These prevailing southwesterly winds locally enhanced precipitation on the southwestern end of the PCB; multiple influences of mountain waves, airflow convergence, and drifted particles are possible factors for causing precipitation on the northeastern side of the TMR. During stage II, the prevailing winds changed from easterlies to northeasterlies offshore from Gangneung. The easterly winds decelerated and were deflected locally along the mountainous coast, and this blocked zone interacted with the oncoming flow to trigger a precipitation band. Consequently, the northeasterly winds helped push the precipitation band toward the coast, causing heavy precipitation in Gangneung. The observational evidence presented shows that the interaction of temporally changing winds accompanying the movement of an LPS over topography is a critical factor for determining the distribution and intensity of precipitation.

ZOTINO III: AN EARLY IRON AGE METALLURGICAL CENTER IN THE TRANS-URALS

In 1974 and 1977, an archaeological expedition from the Ural State University excavated part (441 m2 ) of a fortifi ed Early Iron Age manufacturing site on the Bagaryak River near Zotino, in the forest zone of the Trans-Urals foothills. The site, measuring 80 m by 50–66 m (total area, 3800 m2 ), is located on a 40–43 m high cliff. Its northeastern inland side is protected by a low stone and earthen wall, preserved to the height of 0.75 m, and is delimited by a shallow outer drainage ditch. The single entrance is ~2 m wide. Under the wall, there is a thin layer of buried soil with fragments of the Itkul ceramics. Inside the wall, carbonaceous sandy loam, pieces of calx, and charred remains of wooden structures were found. Our reconstruction suggests that the original 2 m wide wall consisted of two rows of logs and a built-in square tower ~3.0 m by 2.6 m. The base of the walls and tower were strengthened with rubble, and its outer face was enforced with limestone slabs. Near the wall and along the northwestern edge of the site’s inner space, remains of three adobe platforms for processing copper and iron were identifi ed, two dug-in ovens, a utility pit and, apparently, remains of an adobe melting furnace. This is the easternmost and latest (400–100 BC) seasonal fortifi ed metallurgical center of Itkul—an autochthonous culture in the forest zone of the eastern Ural Mountains. In the forest-steppe east and south of it, on the lower reaches of the Sinara and Karabolka rivers, the westernmost fortresses built by the Gorokhovo herders (500–100 BC) are situated—the likely source of the Itkul fortifi cation tradition.

Channel adjustment after artificial neck cutoffs in a meandering river of the Zoige basin within the Qinghai-Tibet Plateau, China

Neck cutoff is an essential process that significantly changes the morphodynamic characteristics of a meandering bend. In reality, however, observing natural processes of a neck cutoff is very difficult. In this study, we artificially triggered neck cutoffs by excavating a 0.4 m (width) × 0.5 m (depth) ditch to connect the beginning and ending of two highly convoluted bends along a meandering tributary of the upper Black River, a major tributary of the Upper Yellow River situated in the northeastern side of the Qinghai-Tibet Plateau in China. Our morphologic and hydraulic measurements in summers of 2013, 2014, 2016, and 2017, the subsequent hydraulic-geometry analysis, and three-dimensional simulation showed that both artificial ditches expanded fast to the size comparable to the former channel in a three-year period and the oxbow channel was disconnected from the former channel quickly, though sediment supply may be limited in this area. The morphological adjustment was featured by (1) distinct temporal trends of the development of the width/depth ratio between the two cutoff channels, (2) different diversion factors of the total discharge to the cutoff channel, and (3) diverse interaction patterns between cutoff and former channels. These discrepancies were supported by simulated different three-dimensional velocity distributions in the two cutoff channels, suggesting the importance of the clustered local velocities. Comparing these results with those reported in earlier studies showed that besides channel slope, unit stream power, and bank strength, the diversion angle between the cutoff and former channel played an important role in controlling channel adjustment. The discrepancy of the adjustment processes between the cutoff channel in this study and those in two previous ones revealed that channel adjustment after neck cutoff behaved differently under different physical settings and require more field-based studies.