Inland Plateau Research Articles

Early or Middle Stone Age? The lithic assemblage of Capangombe – Santo António, Namibe Province (Angola)

Capangombe – Santo António is an open-air site located 596m a.s.l. at the foothill of Morro Santo António, Namibe Province (southwest Angola). The inselberg of Santo António is associated to the Chela escarpment developing from the Marginal Mountain range parallel to the Atlantic Ocean, separating the Angolan inland plateau from the coastal semi-arid to arid plain. A dissected valley formed by the Leba-Capangombe stream exposed a conglomerate with abundant stone tools assigned to the Early Stone Age (ESA). The site was discovered in 1966 by Miguel Ramos, who collected a total of 1776 lithic artifacts, and further published a small report about the assemblage in 1971. In this preliminary analysis, Ramos focused on cleavers using the “French school” typology for the “hachereaux” in Northern Africa and concluded that there are several morphotypes identified in Capangombe-Santo António with specific features, suggesting the occurrence of a local tradition for the Late ESA/Middle Stone Age (MSA). The study presented here is a new analysis of the lithic assemblage curated at the University of Lisbon, Portugal. A sample of 1017 artefacts was analyzed for this project applying an extended descriptive methodology to characterize lithic raw material procurement, reduction sequences and typological classes. The chrono-cultural model initially proposed for the site is revised thanks to recent advances in Stone Age studies.

Karyotype differentiation in the Nothobranchiusugandensis species group (Teleostei, Cyprinodontiformes), seasonal fishes from the east African inland plateau, in the context of phylogeny and biogeography.

The karyotype differentiation of the twelve known members of the Nothobranchiusugandensis Wildekamp, 1994 species group is reviewed and the karyotype composition of seven of its species is described herein for the first time using a conventional cytogenetic protocol. Changes in the architecture of eukaryotic genomes often have a major impact on processes underlying reproductive isolation, adaptation and diversification. African annual killifishes of the genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), which are adapted to an extreme environment of ephemeral wetland pools in African savannahs, feature extensive karyotype evolution in small, isolated populations and thus are suitable models for studying the interplay between karyotype change and species evolution. The present investigation reveals a highly conserved diploid chromosome number (2n = 36) but a variable number of chromosomal arms (46-64) among members of the N.ugandensis species group, implying a significant role of pericentric inversions and/or other types of centromeric shift in the karyotype evolution of the group. When superimposed onto a phylogenetic tree based on molecular analyses of two mitochondrial genes the cytogenetic characteristics did not show any correlation with the phylogenetic relationships within the lineage. While karyotypes of many other Nothobranchius spp. studied to date diversified mainly via chromosome fusions and fissions, the N.ugandensis species group maintains stable 2n and the karyotype differentiation seems to be constrained to intrachromosomal rearrangements. Possible reasons for this difference in the trajectory of karyotype differentiation are discussed. While genetic drift seems to be a major factor in the fixation of chromosome rearrangements in Nothobranchius, future studies are needed to assess the impact of predicted multiple inversions on the genome evolution and species diversification within the N.ugandensis species group.

Subsurface heat conduction along the CHINARE traverse route, East Antarctica

AbstractUsing data from three automatic weather stations (LGB69, Eagle and Dome A) from distinctly different climatological zones along the CHINARE (Chinese National Antarctic Research Expedition) traverse route from Zhongshan Station to Dome A, we investigated the characteristics of meteorological conditions and subsurface heat conduction. Spatial analysis indicated decreasing trends in air temperature, relative humidity and wind speed from the coastal katabatic wind zone to the inland plateau region, and air temperatures clearly showed a strong daily variability in winter, suggesting the effect from the fluctuation in the Antarctic atmospheric system. We also analyzed the optimal response time of the 1 and 3 m depth snow temperatures to the 0.1 m depth snow temperature for each site under clear/overcast and day/night situations. This showed an important enhancement to the heat transfer from shortwave radiation penetration. Using an iterative optimization method, we estimated the subsurface heat conduction variations along the transect. This was ~3–5 W m–2. Multiple maxima in daily mean subsurface fluxes were found in winter, with a typical value above 2 W m–2, while a single minimum value under –2 W m–2was found in summer. On an annual scale, a larger mean loss of subsurface heat conduction was observed in the inland plateau compared to in the coastal katabatic area. Finally, we discussed the possible influences of turbulent and radiant transport on the vertical heat response and confirmed the wind enhancement on the growth of thermal conductivity. This preliminary study provides a brief perspective and an important reference for studying subsurface heat conduction in inland areas of Antarctica.

Research on the spatiotemporal coupling relationships between land use/land cover compositions or patterns and the surface urban heat island effect.

Urbanization leads to changes in landscape configuration and land use/land cover (LULC) patterns, and these changes are important factors affecting the surface urban heat island (SUHI) effect. However, from the perspective of spatiotemporal changes, quantitative analytical results regarding the impacts of the LULC composition, configuration, and pattern in inland plateau lakeside cities on the SUHI effect, and the responsive relationships among these factors remain unclear. By combining satellite remote sensing data with analytical methods, such as urban-rural gradients, spatial statistics, and landscape pattern indices, the impacts of LULC changes on the SUHI effect in Kunming, China, are revealed. The results show the following. (1) The explosive growth in impervious surfaces (ISs) caused by urbanization, leading to changes in the LULC composition, configuration and pattern, is the main reason for the deterioration of the SUHI effect. Over the past 30years, Kunming's ISs have increased by 304.58 km2, SUHI has expanded by 764.26 km2, and the regional average land surface temperature (LST) has increased by 1°C. (2) This study also found that a large area of bare ground is another important reason for the sharp rise in LST, explaining why bare land (BL) has the highest average LST (28.72°C). (3) The pattern of LULC can well explain the spatial distribution characteristics of SUHIs. The normalized difference built-up index (NDBI), normalized difference bareness index (NDBaI), and LST have the same change curve along the urban-rural gradient, while the normalized difference vegetation index (NDVI), modified normalized difference water index (MNDWI), and LST have opposite trends. (4) ISs and water body (WB) are the main types of warming and cooling, respectively, but the warming effect of ISs is greater than the cooling effect of WB. From the average value of the correlation coefficient with LST, NDBI (0.84) > MNDWI (-0.63). (5) Kunming's remote sensing index values do not have simple linear relationships with the LST. NDBaI, NDBI, and LST show significant exponential relationships, and NDVI, MNDWI, and LST show significant quadratic polynomial relationships. (6) The dominant landscape type determines the correlation between the landscape shape index (LSI) and the LST of green spaces (GSs). (7) Adopting a simple and regular landscape layout can effectively reduce the SUHI effect. These research results could provide a scientific decision-making basis for the spatial urban planning and ecological construction of Kunming and could have practical significance for guiding the green, healthy, and sustainable development of the city.

Surface Mass Balance Controlled by Local Surface Slope in Inland Antarctica: Implications for Ice‐Sheet Mass Balance and Oldest Ice Delineation in Dome Fuji

AbstractThe limited number of surface mass balance (SMB) observations in the Antarctic inland hampers estimates of ice‐sheet contribution to global sea level and locations with million‐year‐old ice. We present finely resolved SMB over the past three centuries in a low‐accumulation region with significant depth hoar formation on Dome Fuji derived from ∼1,100 km of microwave radar stratigraphy dated with a firn core. The regional‐mean SMB over the past 264 years is estimated to ∼22.5 ± 3.3 kg m−2 a−1, but with large local variability of up to 30%. We found that local SMB is negatively correlated with surface slope at scales of a few hundred meters, resulting in anomalous zones of low SMB which represent as much as 8–10% of the total SMB on the inland plateau if the SMB‐slope relationship is more widely valid. This impact should be investigated further to improve estimates of Antarctic mass balance and sea‐level contribution.

Temporal and Spatial Distribution and Fluorescence Spectra of Dissolved Organic Matter in Plateau Lakes: A Case Study of Qinghai Lake

Dissolved organic matter (DOM) has a great impact on the main pollution indicators of lakes (such as chemical oxygen demand, COD). Therefore, DOM is the research basis for understanding the meaning of the water environment and the laws of the migration and transformation of pollutants. Qinghai Lake is one of the world’s typical inland plateau lake wetlands. It plays important roles in improving and regulating the climate and in promoting a virtuous regional ecological cycle. In recent years, with the acceleration of urbanization and the rapid development of tourism, under the background of climate change, and with grassland degradation and precipitation change, the whole basin of Qinghai Lake has been facing great ecological pressure. In order to comprehensively explore the water environment of Qinghai Lake and to protect the sustainable development of the basin, a systematic study was carried out on the whole basin of Qinghai Lake. The results show the following: (1) from 2010 to 2020, the annual average value of CODCr in Qinghai Lake fluctuated in the range from class III to class V according to the surface water environmental quality standard, showing first a downward trend and then an upward trend. (2) The concentration of CDOM in Qinghai Lake had obvious temporal and spatial changes. (3) The spatial distribution of the total fluorescence intensity of FDOM in water was also different in different seasons. However, in the three surveys, the area with the highest total fluorescence intensity of FDOM in the water body appeared near Erlangjian in the south of Qinghai Province, indicating that anthropogenic sources are the main controlling factors of dissolved organic matter in the lake.

Season determines the efficiency of a rapid sampling protocol for non‐acarine arachnids (Chelicerata: Arachnida) in Afrotemperate grassland biotopes

AbstractThe Grassland Biome covers large parts of the inland plateau of South Africa, but many areas have historically been poorly sampled for arachnids. This study aimed to survey non‐acarine arachnids in western KwaZulu‐Natal and compare their biodiversity during winter (June and July 2015) and summer (December 2015 and January 2016). A standardised rapid sampling protocol was used to collect specimens from four biotopes (riparian bush, montane grasslands, lowland grasslands and Eucalyptus plantations). In total, 4623 non‐acarine arachnids were collected, representing five orders, of which 185 spp. were represented by adult specimens (n = 774). Although overall abundance (including immatures) was higher in winter, more adult individuals and species were collected in summer (n = 425, 139 spp.) than in winter (n = 349, 89 spp.). Day hand collecting yielded the highest abundance and species richness during both seasons, and largest number of unique species overall, while Berlese–Tullgren funnels were generally the least efficient method. Seasonal changes in assemblage composition are the result of considerable differences in phenology between the dominant families, resulting in only a small degree of overlap (23.2%) in the adult arachnid fauna between seasons. Several methods collected low adult species richness, but when combined, sample completion values were above 50% for both seasons and overall. This study has highlighted the importance of implementing rapid sampling protocols in multiple seasons to broaden knowledge of local species richness, to effectively address conservation and management objectives.

Initial Results of Long-term Continuous Observation of Lightning Discharges by FALMA in Chinese Inland Plateau Region

We started a long-term continuous observation of lightning discharges in the Chinese inland plateau region using a fast antenna lightning mapping array (FALMA). During the first year of observation, 2019, we recorded lightning discharges on 25 days in Yinchuan city, the capital of Ningxia. Most of the lightning discharges appeared to occur in the afternoons of individual thunderstorm days in August. We studied the cloud-to-ground (CG) flash percentages, lightning discharge source spatiotemporal distributions, and preliminary breakdown (PB) process characteristics for the two thunderstorm cases that produced the most frequent lightning flashes in 2019 over a wide area. It was found that (1) CG flashes in these two thunderstorms accounted for 28.4% and 32.5% of total lightning flashes, respectively; (2) most lightning discharge sources in these two thunderstorms occurred at temperatures between 5 and −30 °C, with a peak at around −10 °C; and (3) more than 90% of well-mapped PB processes of intracloud (IC) flashes propagated downward. By overlapping the altitudes and the progression directions of the PB processes on the lightning source spatiotemporal distributions, we inferred that the main negative charge of the two storms observed in Ningxia, China, was at a height of around −15 to −25 °C (7 to 9 km) and the main positive charge was at a height of around 5 to 0 °C (2 to 4 km).

<p><strong><em>Petalidium kaokoense</em> (Acanthaceae), a new species from Namibia</strong></p>

Petalidium kaokoense, here described as a new species, is only known from the Hartmann Mountains and one other location on the inland plateau in the Kaokoveld Centre of Endemism, northwestern Namibia, where it grows on hillsides and mountain slopes. Diagnostic characters for P. kaokoense include the stout trunk on older plants, white bark, peeling on the younger branches in long, narrow strips, stellate trichomes, short inflorescences of racemoid dichasia with acute linear-oblanceolate or linear-lanceolate bracts, flowers with maroon corollas with the two upper lobes connate towards the base and the lower lobe with two yellow spots near the base. A comparison of some of the more prominent morphological features to differentiate between Petalidium kaokoense and its presumed close relative, the morphologically similar P. physaloides, is provided. Based on IUCN Red List categories and criteria, a conservation assessment of Vulnerable (VU D1) is recommended for the new species.

Spatial and temporal variations of refractory black carbon along the transect from Zhongshan Station to Dome A, eastern Antarctica

Abstract Refractory black carbon (rBC) aerosols emitted by biomass burning and fossil fuel combustion can cause significant climatic forcing when it deposited on the snow. The Southern Hemisphere (SH) biomass burning emissions represent a significant part of rBC in and around Antarctica. Here we present the spatial and temporal variations of rBC from the surface snow and snow pits samples along the coastal Zhongshan Station (ZSS) to inland Dome A transect in Lambert Glacier region of eastern Antarctica. The geometric mean concentrations of surface snow rBC was 0.017 ± 0.018 ng g−1 and showed higher values in the inland plateau region (900–1248 km, 0.031 ± 0.024 ng g−1) than the coastal region (0–400 km, 0.011 ± 0.005 ng g−1) and there exist similar spatial results for the inland snowpit (0.021 ± 0.017 ng g−1) and coastal snowpit (0.018 ± 0.013 ng g−1). The records from the coastal snowpit (SP-A) show that the rBC from 2009 to 2016 displays weak seasonal variations, while in the inland snowpit (SP–C) the records spans from 1950 to 2015 and showed the rBC concentrations vary and relate with the open biomass burning emission in the Southern Hemisphere.

Изменение поглотительной способности почв по элементам рельефа балочных водосборов ЦЧР

Работа посвящена изучению особенностей состава почвенного поглощающего комплекса (ППК) по элементам рельефа балочного водосбора. Целью работы является выявление зависимости ППК от степени развития и характера водной эрозии и аккумуляции. Для достижения поставленной цели был решен ряд задач: проведение площадной почвенно-эрозионной съемки балочного водосбора; определение физико-химических и физических свойств почв по ГОСТированным и общепринятым методикам; сравнительный анализ поглотительных свойств почв по элементам рельефа балочного водосбора. Высокая степень эродированности территории определяет актуальность исследования поглотительных свойств почв, подверженных смыву и намыву. Объектом исследования являются почвы водосборной площади балки «Лог Репный». Согласно почвенно-эрозионному районированию Воронежской области объект исследования расположен в Семилукско-Нижнедевицком районе. Наблюдалось обеднение всего профиля почв водораздельных склонов и берега балки илистой фракцией за счет влияния эрозии почв и денудации. На днище балки было зафиксировано обогащение верхней части почвенного профиля илистой фракцией под влиянием аккумуляции почвенного материала, смываемого с вышележащих склонов. Поглотительная способность почв различных элементов рельефа водосборной площади балки «Лог Репный» может быть охарактеризована с помощью величины суммы поглощенных оснований. Наибольшая сумма поглощенных оснований наблюдалась на водораздельном плато (15.73 ммоль/100 г почвы). На берегу балки в условиях влияния процесса денудации зафиксировано уменьшение суммы поглощенных оснований в 2.5 раза. На днище балки в зоне преимущественной аккумуляции смываемого со склонов почвенного материала сумма поглощенных оснований была ниже, чем на водоразделе в 1.4 раза. Это связано с различным содержанием илистой фракции в этих почвах. Так, в почвах водоразделов илистая фракция составляла 24.8%, на берегу балки ее содержание было в 2.5 раза ниже, а на днище балки вновь возрастало до 22.4 %. Установлена зависимость суммы поглощенных оснований почв от перераспределения илистой фракции под влиянием эрозии и аккумуляции почв.

Predator and scavenger movements among and within endangered seabird colonies: Opportunities for pathogen spread

Abstract The spatial structure of host communities is expected to constrain pathogen spread. However, predators and/or scavengers may connect distant host (sub)populations when foraging. Determining whether some individuals or populations play a prominent role in the spread of pathogens is critical to inform management measures. We explored movements and epidemiological status of brown skuas Stercorarius antarcticus, the only avian terrestrial consumer native of Amsterdam Island (Indian Ocean), to assess whether and how they could be involved in the spread of the bacterium Pasteurella multocida, which recurrently causes avian cholera outbreaks in endangered albatross and penguin species breeding on the island. High proportions of seropositive and DNA‐positive individuals for P. multocida indicated that skuas are highly exposed to the pathogen and may be able to transmit it. Movement tracking revealed that the foraging ranges of breeding skuas largely overlap among individuals and expand all along the coasts where albatrosses and penguins nest, but not on the inland plateau hosting the endemic Amsterdam albatross Diomedea amsterdamensis. Considering the epidemiological and movement data, skua movements may provide opportunity for pathogen spread among and within seabird colonies. Synthesis and applications. This work highlights the importance of considering the behaviour and epidemiological status of predators and scavengers in disease dynamics because the foraging movements of individuals of such species can potentially limit the efficiency of local management measures in spatially structured host communities. Such species could thus represent priority vaccination targets to implement efficient management measures aiming at limiting pathogen spread and also be used as sentinels to monitor pathogen circulation and evaluate the effectiveness of management measures.

Cenozoic deformation of the South African plateau, Namibia: Insights from planation surfaces

Passive margins and associated inland areas display complex vertical displacements that have been abundantly described offshore but much less so onshore due to erosion. Planation surfaces are ubiquitous markers inland that can be used as a proxy both climatic conditions and changes in vertical displacements induced by both short (faults) and long (tilting, flexure) wavelength deformations. We propose 1) a synthetic typology of the planation surfaces driven by a genetic process (weathering versus mechanical erosion), and 2) a method to use these surfaces to map short and long wavelength deformations. This methodology was applied to the Namibian margin and inland plateau to quantify the Cenozoic deformation. The results show that the Namibian margin was affected by bulging during the Oligocene and by an E-W to NW-SE extension during the Late Miocene and Pliocene. The bulge is parallel to the shoreline with a wavelength of 300km and an amplitude up to 500m. After investigating the available deformation processes, we propose that an increase in the spreading rate along the mid-oceanic ridge during the Oligocene generated this bulging. The vertical displacement is partially maintained afterwards via isostasy because of mass loss generated by scarp retreat. A minimum average rate of scarp retreat of 5km/Myr was calculated, which is high compared to the rates estimated in other places in the world. We ascribe this high value to the prior intense weathering period. Indeed, the alteration largely degraded the bedrock and facilitated the formation of the subsequent scarp. This study also reveals that the high reliefs of the Damara domain existed before the Cenozoic, induced by a reactivation of the Damara structures.

Comparative analysis of IgG and IgG subclasses against Plasmodium falciparum MSP-119 in children from five contrasting bioecological zones of Cameroon

BackgroundStudies reporting the natural immune responses against malaria in children from different geographical settings in endemic areas are not readily available. This study was aimed at comparing the immune responses against Plasmodium falciparum MSP-119 antigen in children from five contrasting bioecological zones in Cameroon.MethodsIn a cross-sectional survey, children between 2 and 15 years, were enrolled from five ecological strata including the south Cameroonian equatorial forest, sudano-sahelian, high inland plateau, high western plateau, and the coastal strata. The children were screened for clinical malaria (defined by malaria parasitaemia ≥ 5000 parasites/µl plus axillary temperature ≥ 37.5 °C). Their antibody responses were measured against P. falciparum MSP-119 antigen using standard ELISA technique.ResultsIn all, 415 children comprising 217 (52.3%) males participated. Total IgG and IgG1–IgG4 titres were observed to increase with age in all the strata except in the sudano-sahelian and high inland plateau strata. Total IgG and IgG1–IgG4 titres were significantly higher in the coastal strata and lowest in the high inland plateau (for IgG1 and IgG2) and sudano-sahelian strata (for IgG3 and IgG4). Titres of the cytophilic antibodies (IgG1 and IgG3) were significantly higher than the non-cytophilic antibodies (IgG2 and IgG4) in all the strata except in the sudano-sahelian and high inland plateau strata. Total IgG and IgG subclass titres were significantly higher in children positive for clinical malaria compared to negative children in all study sites except in the high western plateau and coastal (for IgG1 and IgG3), and the sudano-sahelian strata (for all antibodies). Furthermore, a significant positive correlation was observed between parasite density and IgG2 or IgG4 titres in all study sites except in the south Cameroonian equatorial forest and sudano-sahelian strata.ConclusionsThis study showed that antibody responses against MSP-119 vary considerably in children from the different bioecological strata in Cameroon and could be linked to the differential exposure to malaria in the different strata. Furthermore, the rate of antibody acquisition was not observed to increase in an age-dependent manner in low transmission settings.

CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers

Abstract. For three austral summer seasons (2013–2016, each from December to February) aerosol particles arriving at the Belgian Antarctic research station Princess Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized. This included number concentrations of total aerosol particles (NCN) and cloud condensation nuclei (NCCN), the particle number size distribution (PNSD), the aerosol particle hygroscopicity, and the influence of the air mass origin on NCN and NCCN. In general NCN was found to range from 40 to 6700 cm−3, with a median of 333 cm−3, while NCCN was found to cover a range between less than 10 and 1300 cm−3 for supersaturations (SSs) between 0.1 % and 0.7 %. It is shown that the aerosol is dominated by the Aitken mode, being characterized by a significant amount of small, and therefore likely secondarily formed, aerosol particles, with 94 % and 36 % of the aerosol particles smaller than 90 and ≈35 nm, respectively. Measurements of the basic meteorological parameters as well as the history of the air masses arriving at the measurement station indicate that the station is influenced by both marine air masses originating from the Southern Ocean and coastal areas around Antarctica (marine events – MEs) and continental air masses (continental events – CEs). CEs, which were defined as instances when the air masses spent at least 90 % of the time over the Antarctic continent during the last 10 days prior to arrival at the measurements station, occurred during 61 % of the time during which measurements were done. CEs came along with rather constant NCN and NCCN values, which we denote as Antarctic continental background concentrations. MEs, however, cause large fluctuations in NCN and NCCN, with low concentrations likely caused by scavenging due to precipitation and high concentrations likely originating from new particle formation (NPF) based on marine precursors. The application of HYSPLIT back trajectories in form of the potential source contribution function (PSCF) analysis indicate that the region of the Southern Ocean is a potential source of Aitken mode particles. On the basis of PNSDs, together with NCCN measured at an SS of 0.1 %, median values for the critical diameter for cloud droplet activation and the aerosol particle hygroscopicity parameter κ were determined to be 110 nm and 1, respectively. For particles larger than ≈110 nm the Southern Ocean together with parts of the Antarctic ice shelf regions were found to be potential source regions. While the former may contribute sea spray particles directly, the contribution of the latter may be due to the emission of sea salt aerosol particles, released from snow particles from surface snow layers, e.g., during periods of high wind speed, leading to drifting or blowing snow. The region of the Antarctic inland plateau, however, was not found to feature a significant source region for aerosol particles in general or for cloud condensation nuclei measured at the PE station in the austral summer.

The potential for domestic thermal insulation retrofits on the South African Highveld

The South African Highveld is a portion on the inland plateau characterized by low winter ambient temperatures. Studies done in several climatic regions around the world have found a positive relationship between inadequate housing and low indoor temperatures during the winter season. Prolonged exposure to low indoor temperature is a threat to human physical health. This study characterizes indoor human thermal comfort conditions in typical low-income residential dwellings during the winter season. Mapping indoor human thermal comfort can assist in exploring the potential for domestic thermal insulation retrofits interventions. In-situ temperature measurements were done in 2014, 2016 and 2017 across three Highveld settlements of kwaZamokuhle, kwaDela, and Jouberton. The sample included a mixture of old (pre-1994), post 1994 Reconstruction and Development Programme (RDP) as well as non-RDP structures. Findings were that 88% of sampled dwellings in Jouberton 2016, 86% in Jouberton 2017, 62% in kwaDela and 58% in kwaZamokuhle had daily mean temperatures below the WHO guideline of 18°C. These low indoor temperatures indicate poor insulation in these sampled dwellings. Across all settlements, insulated dwellings had higher daily mean indoor temperatures than non-insulated dwellings. These findings indicate the potential to use thermal insulation retrofits in improving indoor thermal conditions as the majority of dwellings are non-insulated thereby exposing occupants to low indoor temperatures.

Measurements of vertical electric field in a thunderstorm in a Chinese inland plateau

Abstract. A balloon-borne instrument was designed to measure the electric field in thunderstorms. One case of thunderstorm was observed in the Pingliang region (35.57∘ N, 106.59∘ E; and 1620 m above sea level, a.s.l.) of a Chinese inland plateau, through penetration by the balloon-borne sounding in the early period of the mature stage. Results showed that the sounding passed through seven predominant charge regions. A negative charge region with a depth of 800 m located near the surface, and a positive charge region appeared in the warm cloud region; their mean charge densities were −0.44 ± 0.136 and 0.43 ± 0.103 nC m−3, respectively. Five charge regions existed in the region colder than 0 ∘C, and charge polarity alternated in a vertical direction with a positive charge at the lowest region. The mean charge densities for these five regions were 0.40±0.037 nC m−3 (−9.5 to −4 ∘C), -0.63±0.0107 nC m−3 (−18 to −14 ∘C), 0.35±0.063 nC m−3 (−27 to −18 ∘C), -0.36±0.057 nC m−3 (−34 to −27 ∘C), and 0.24±0.06 nC m−3 (−38 to −34 ∘C). We speculated that the two independent positive charge regions in the lower portion are the same charge region with a weak charge density layer in the middle. The analysis showed that the real charge structure of the thunderstorm is more complex than the tripole model, and the lower dipole is the most intensive charge region in the thunderstorm. Keywords. Meteorology and atmospheric dynamics (atmospheric electricity)

Erosion at extended continental margins: Insights from new aerogeophysical data in eastern Dronning Maud Land

Modelling-, rock cooling-, sedimentation- and exposure-based interpretations of the mechanisms by which topography evolves at extended continental margins vary widely. Observations from the margin of Dronning Maud Land, Antarctica, have until now not strongly contributed to these interpretations. Here, we present new airborne gravity and radar data describing the eastern part of this margin. Inland of a tall (2.5 km) great escarpment, a plateau topped by a branching network of valleys suggests preservation of a fluvial landscape with SW-directed drainage beneath a cold-based ice sheet. The valley floor slopes show that this landscape was modified during a period of alpine-style glaciation prior to the onset of the current cold-based phase around 34 Ma. The volume of sediments in basins offshore in the Riiser-Larsen Sea balances with the volume of rock estimated to have been eroded and transported by north-directed drainage from between the escarpment and the continental shelf break. The stratigraphy of these basins shows that most of the erosion occurred during the ~40 Myr following late Jurassic continental breakup. This erosion is unlikely to have been dominated by backwearing because the required rate of escarpment retreat to its present location is faster than numerical models of landscape evolution suggest to be possible. We suggest an additional component of erosion by downwearing seawards of a pre-existing inland drainage divide. The eastern termination of the great escarpment and inland plateau is at the West Ragnhild trough, a 300 km long, 15–20 km wide and up to 1.6 km deep subglacial valley hosting the West Ragnhild glacier. Numerous overdeepened (by >300 m) segments of the valley floor testify to its experience of significant glacial erosion. Thick late Jurassic and early Cretaceous sediments fanning out from the trough's mouth into the eastern Riiser-Larsen Sea betray an earlier history as a river valley. The lack of late Jurassic relief-forming processes in this river's catchment in the interior of East Antarctica suggests this erosion was related to regional climatic change.

Edaphic characterization and plant zonation in the Qaidam Basin, Tibetan Plateau

This paper presents a study of edaphic characteristics and their relationship with plant distribution in the Qaidam Basin, Tibetan Plateau, and establishes a distribution model for plants in sandy gravel Gobi to dry salt lake areas. All of the communities in the study area were dominated by plants with strong saline-alkaline tolerance. In this area, salts appeared to migrate to the surface; the surface soil was striped, and the salt distribution varied from sandy gravel Gobi to dry salt lake areas. The salt composition mainly consisted of NaCl in the surface crust. In the subsurface layers, the salt composition was dominated by Ca2+, Cl− and SO42−. The type of vegetation at the study site can be divided into two categories: salt-tolerant vegetation and weakly salt-tolerant vegetation. The salt-tolerant vegetation is influenced by Na+, Cl−, and the salinity. The soil of these vegetation communities had a higher salt and Na+ concentration and a lower Ca2+ and K+ concentration. The weakly salt-tolerant vegetation is mainly affected by the Ca2+/Na+ and K+/Na+ ratios. Based on the above results, a vegetation distribution model for saline lakes on the inland plateau was established.

Intensified impact of North Atlantic Oscillation in May on subsequent July Asian inland plateau precipitation since the late 1970s

ABSTRACTThe relationship between the North Atlantic Oscillation (NAO) in May and precipitation in the Asian inland plateau (AIP) in following July has experienced a significant enhancement since the late 1970s. This study investigates the factors for this inter‐decadal change of the NAO–AIP precipitation connection. Before the late 1970s, geopotential height anomalies related to the May NAO exhibited a dipole pattern confined to the North Atlantic from May to June and decayed in July. As a result, the impact of the May NAO on the AIP precipitation in July is weak. In contrast, after the late 1970s, geopotential height anomalies associated with the May NAO persisted into July. The analysis in this study finds that the May NAO influences July AIP precipitation via modulating the Polar–Eurasia teleconnection (POL). After (before) the late 1970s, the connection between the May NAO and the POL was strong (weak), explaining the inter‐decadal change in the May NAO–July AIP precipitation relationship. Further analysis suggests that the strengthening of the relationship between the May NAO pattern and the July POL after the late 1970s may be attributed to the inter‐decadal contraction of the Northern Hemisphere circumpolar vortex.