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Water exhibits various politico-economic dynamic. Water scarcity can lead to conflicts, and it lies at the core of Iran's environmental crises. The literature on Iran's water crisis indicates the effects of this issue in terms of multidimensional environmental degradation, community disintegration, and state-society and intercommunal conflict. Approximately 28 million of Iran's 85 million residents reside in water-stressed areas, a situation identified as 'water bankruptcy'. The water shortage is experienced differently across the country. The plateau's central regions, home to Iran's major industries, are where the worst water deficit is occurring. However, regions with abundant water resources have also been impacted. These regions – known as 'donor basins' – due to intensive and disproportional inter-basin water transfer and other engineering interventions deployed by the Government to deal with the water shortage of the central regions, suffer from a different form of water crisis. A condition of asymmetrical and conflictual power relations between the state and subaltern communities in Iran's peripheral regions has been created. This paper argues that this constitutes environmental racism, characterised by multilayered impoverishment and unsustainable development among communities in the donor regions. [ABSTRACT FROM AUTHOR]

Investigators seeking to solve the mystery of rock varnish formation have yet to embrace hypothesis testing. Thus, this paper presents nine tests that assess the validity of the eight hypotheses proposed over the last four decades to explain varnish formation. An almost singular focus on manganese (Mn)-enrichment by many in varnish research may have led to six of the eight hypotheses failing to explain iron (Fe)-enrichment, as well as why clay minerals dominate the composition of rock varnish. Many varnish researchers displayed a sampling bias by collecting samples only from hot and dry deserts; thus, it should be of no surprise that four hypotheses failed a test of explaining varnishes in different climates; five hypotheses failed to explain varnishes in subsurface locations; and seven hypotheses failed to explain differences in varnish growth rates in hot deserts versus wetter locations. In the end, seven of eight proposed hypotheses to explain varnish formation failed more than five tests, any one of which would falsify the hypothesis. Only one hypothesis "passed" all nine tests. [ABSTRACT FROM AUTHOR]

Since the 1990s, an international consensus has been emerging with respect to the methods used to identify and assess geosites. These conventional methodologies generally differentiate between the intrinsic or scientific-natural dimension and the social dimension in the potential value of the geological elements. The aim of this article is to analyse the possible existence of other concepts that may underlie these criteria and that could be operating as evaluation parameters even though they are not explicitly and formally described as such in the published studies. An exhaustive analysis of articles on geosite inventories published in Science Citation Index journals in the last 15 years revealed a systematic reference to conceptions of magnitude (in the sense of degree of development and physical prominence) in geosite descriptions around the world, and in particular with respect to sites of geomorphological interest. To contrast this indication, we subjected the geosites inventory of Lanzarote (Canary Islands, Spain) to a Magnitude Rule hypothesis. This inventory is part of the Spanish Geosites Inventory (IELIG, for its initials in Spanish), which was carried out using conventional assessment procedures. Applying this rule, according to which each geosite is the most prominent example of its typology within the reference geological domain, we obtained an almost complete match. That is, geomorphological sites that were selected, a priori, according to intrinsic and social dimension were also (or one could even say 'actually') selected, implicitly, on the predominant basis of magnitude. This paper discusses why and how the magnitude parameter may be playing a key role as a subliminal non-explicit driver in the evaluation of geosite relevance, and how this finding may open new perspectives and bring methodological advantages in the inventory of geological heritage. [ABSTRACT FROM AUTHOR]

This paper analyzes the stabilizing effect of stone dust, granite dust, marble dust, and calcium lignosulphonate on construction materials and natural soils during road construction. The ultimate aim was to enhance the soil's engineering properties such that the pavement constructed could correctly withstand the load applied. To achieve this, every stabilizer was amalgamated with the soil at various percentages between 5 and 50%. Measurements were made of Atterberg limit tests, moisture content, and specific gravity. The research demonstrated that a diminution in optimal moisture content was seen, with an elevation in maximum dry density and California bearing ratio (CBR). Enhancements in the unconfined compressive strength were also identified. The outcomes determined that the untreated soil's CBR was 2.27% and in the case of soil with 45% additives, the CBR attained was 5.05%. When the soil was mixed with 50% additives, performance of 30.21%, 17.42%, and 12.82% was exhibited for (a) liquid limit, (b) plastic limit, and (c) plasticity index. Moreover, via the addition of presented stabilizers, the soil's mechanical properties were elevated appreciably. [ABSTRACT FROM AUTHOR]

Modern urban climatology is a part of boundary-layer climatology with a focus on the urban effects on the atmosphere. The best known of these effects is the urban heat island (UHI), which has been a subject of study for more than 200 years and may be categorised into air, surface and substrate types. Progress on this topic has occurred in various phases associated with theoretical developments, improvements in technology (instruments and computing) and study design, to isolate the causative drivers. The history of the field can be categorised into response-based (descriptive) and process-based (analytic) periods associated with hypothesis generation and testing, respectively. Myrup's paper on simulating the UHI, published in 1969, is at the forefront of this shift in approach and is the first application of numerical modelling to the topic. Its computational methods place the UHI within the context of the surface energy budget and the exchanges of energy, urban characteristics, and the substrate as well as overlying air. The paper is a classic that had considerable impact on the approach that geographical climatology took to examining the UHI; however, it is not without its limitations Careful reading of Myrup's work provides insights into how the field has evolved in the last 50 years. In particular the recurring issues associated with conceputalising the urban thermal effect and challenge of comparing models results with field observations. Remarkably, key urban climate questions on how to cool cities, how to plan cities for future climate, and the factors that impact UHI are still being studied, albeit with more sophisticated models. A numerical model of the urban heat island is part of a rich literature on the UHI that illustrates the development of the urban climate science that deserves to be read and cited. [ABSTRACT FROM AUTHOR]

The Earth and life sciences are replete with portmanteau (blended) words and neologisms. Researchers at the interfaces between the traditional disciplines within the Earth and life sciences have coined dual titles for ‘new’ disciplines, such as geobiology/biogeology and ecohydrology/hydroecology. An upsurge in such coinage over the last few decades reflects a healthy willingness of many researchers to cross traditional disciplinary boundaries and to include the human sphere within their domains. However, some of the titles cause confusion because their meanings are not self-evident; rather, they sometimes demand extra research to reveal their meanings, thus rendering science less ‘open’ at a time when Open Science is being vigorously encouraged. After discussing the question of disciplinary neologisms, the paper probes the interchangeability of 15 dual ‘new’ discipline titles and concludes that six are more-or-less synonymous, three are nonsynonymous, and six are indeterminate for varying reasons. We question the usefulness of some, but by no means all, disciplinary neologisms, given that their meanings are not immediately apparent. Looking beyond portmanteau titles and other neologisms, the paper discusses the rise of interdisciplinary and transdisciplinary research, as seen in the concepts of the Critical Zone, multifunctional landscapes, and Earth System Science, the last of which supports a conceptual model of the planet as an interdependent set of spheres from global to local scales that has the advantages of combining the biotic, abiotic, and human spheres. [ABSTRACT FROM AUTHOR]

During the last deglaciation, atmospheric CO2 increased by about 75 ppm. The deep ocean is likely the dominant source of this atmospheric CO2 rise in the atmospheric pool; however, a consensus accounting for the entire 75 ppm remains elusive. Since the deep ocean cannot account for the entire 75 ppm, the terrestrial environment likely makes up the remainder. This paper provides a mechanism for an unaccounted-for portion of the source of this terrestrial carbon, that being soil organic carbon (SOC) from the tropical montane Andes, and with that, minimum constraints on the contribution of SOC to the total rise in atmospheric CO2 during the last deglaciation. Using numerical climate modeling input into an empirical model derived from tropical montane forests of the Andes Mountains in South America, this study finds that during the last deglaciation, the organic layer thickness was thinning from the Last Glacial Maximum (LGM) to the present (pre-industrial) in the tropical montane Andes. This overall warming and organic layer thickness thinning may have led to a loss of available carbon storage space, causing a leak of CO2 into the atmosphere over this time scale. This study finds an estimate for the contribution of global atmospheric CO2 from SOC in tropical montane Andean soils is likely at least ∼1.4 ppm CO2 since the LGM. [ABSTRACT FROM AUTHOR]

Scientific knowledge advances by the discussions on hypotheses, methods, and results, wherein the contradictory plays a positive role developing new theoretical-methodological approaches. In a positive debate to the progress of the science, the agreements and disagreements must only permeate the scientific scope and based on ethics to be away from the conflicts of interest. From this perspective, after knowing the submission titled Comments on Souza et al. (2022) "Recent geomorphological changes in the Paraiba do Sul delta, South America East Coast" to the journal Progress in Physical Geography: Earth and Environment (PPG), which addressed several issues concerning the results published in that article, we wrote this response to clarify the doubts related to the original paper. The comment's authors focus mainly on da Rocha et al. (2019), a locally published article that did not fully encompass the complexity of processes and geomorphological dynamics related to the delta evolution. Furthermore, it did not present the parameters used in the geochronological analyses in accordance with the international literature. Finally, the discussions presented in the original article contribute to advances in knowledge about the responses of the Paraíba do Sul delta to the Little Ice Age. [ABSTRACT FROM AUTHOR]

The longleaf pine (Pinus palustris Mill.) and related ecosystem is an icon of the southeastern United States (US). Once covering an estimated 37 million ha from Texas to Florida to Virginia, the near-extirpation of, and subsequent restoration efforts for, the species has been well-documented over the past ca. 100 years. Although longleaf pine is one of the longest-lived tree species in the southeastern US—with documented ages of over 400 years—its use has not been reviewed in the field of dendrochronology. In this paper, we review the utility of longleaf pine tree-ring data within the applications of four primary, topical research areas: climatology and paleoclimate reconstruction, fire history, ecology, and archeology/cultural studies. Further, we highlight knowledge gaps in these topical areas, for which we introduce the Longleaf Tree-Ring Network (LTRN). The overarching purpose of the LTRN is to coalesce partners and data to expand the scientific use of longleaf pine tree-ring data across the southeastern US. As a first example of LTRN analytics, we show that the development of seasonwood chronologies (earlywood width, latewood width, and total width) enhances the utility of longleaf pine tree-ring data, indicating the value of these seasonwood metrics for future studies. We find that at 21 sites distributed across the species' range, latewood width chronologies outperform both their earlywood and total width counterparts in mean correlation coefficient (RBAR = 0.55, 0.46, 0.52, respectively). Strategic plans for increasing the utility of longleaf pine dendrochronology in the southeastern US include [1] saving remnant material (e.g., stumps, logs, and building construction timbers) from decay, extraction, and fire consumption to help extend tree-ring records, and [2] developing new chronologies in LTRN spatial gaps to facilitate broad-scale analyses of longleaf pine ecosystems within the context of the topical groups presented. [ABSTRACT FROM AUTHOR]

Reach-scale river restoration or environmental water allocation (EWA) exercises typically address the magnitude and temporal dynamics (frequency, duration, timing, rate of change) of flows required to sustain desirable ecological conditions along a river. The role of geomorphology in this process is to broaden the gaze beyond flows to consider larger and longer-terminteractions between valley lithological structure, and the feed and fate of flow-sediment mixtures. This paper proposes the integration of numerical morphodynamic modelling in evaluations of environmental water requirements for non-perennial riverscapes (channel--riparian--floodplain environments). The paper presents a methodological framework, and proof of concept case study from the Touws River, South Africa, for the application of morphodynamic modelling in EWA. The paper illustrates operational approaches to modelling the complexity of dryland mixed bedrock-alluvial (and mixed-load) riverscapes with highly variable non-perennial flow regimes, including an approach to generating initial bed conditions for numerical experiments by 'morphodynamic spin-up', and approaches to synthesising and presenting numerical experiment output in the formof a dynamic range of potential variability inmetrics of physical habitat suitability and diversity, and disturbance/renewal regimes. Such efforts can assist in enhancing field observations and testing field-based hypotheses of flow-sediment regime--physical habitat associations, extending the timescales of analysis beyond field observation, and constraining uncertainty about the dynamic range of variability in responses to predicted future flow-sediment regime modifications. Further research is needed to develop growth models appropriate for key non-perennial river vegetation types, to support bio- morphodynamic modelling of geomorphology--vegetation interactions, and to determine or predict appropriate inlet sediment concentrations for historical and future modification scenarios. [ABSTRACT FROM AUTHOR]

The lower Usumacinta–Grijalva River Basin contains one of the richest biodiversity landscapes of the Maya region. Our research is based on (1) an integrative literature review of the geomorphological and archaeological papers published about the lower Usumacinta–Grijalva River Basin and (2) topographic analysis of digital elevation models using a geographical information system to explore the relationship between past human settlement and landscape accessibility along the coastal plain of Tabasco. This work provides a new synthesis of previous research and proposes new models for the geomorphic evolution of the lower Usumacinta–Grijalva River Basin in the context of four millennia of human land use and settlement. For the evolution of the strand-plain of the Usumacinta and Grijalva rivers, there are two published geochronological models that provide different chronologies. We discuss here how both geochronological models encompass Pre-Columbian human settlement in the delta. Interestingly, we notice that one of them overlaps a possible high-magnitude flood event (or events) that drove large geomorphic change around 750 CE (1200 BP), with implications for settlement patterns and chronology. Based on topographical analysis of the eastern-distal sector of the Usumacinta–Grijalva delta, we propose a new model for the evolution of this area with implications for the human occupation during the Mesoamerican Terminal Classic and Early Postclassic on the delta. As one of the main conclusions, we propose that the Pom–Atasta water bodies predate much of the Usumacinta–Grijalva delta and the most recent phase of delta building overlays the original lagoon barriers, resulting in a geomorphic setting more attractive to local human occupation after the Terminal Classic period. According to one of the geochronological models of the delta, this dates to ca. 900 CE, preceding the establishment of nearby settlements such as Atasta. [ABSTRACT FROM AUTHOR]

Brenner considers the impacts of this paper, in light of subsequent Maya paleoclimate/paleoenvironmental studies published in the last four decades. This special issue considers physical geography in the Maya Lowlands, a tropical, mostly low-lying carbonate platform in the Yucatan Peninsula of Mexico, Belize, Guatemala, and parts of Honduras and El Salvador. Indeed, much of what we know about this region's environments (i.e., its physical geography and paleoenvironment) derives from work sponsored by archaeology projects funded by the National Geographic Society, the National Science Foundation, the UK Overseas Development Agency, and many other entities, including early support from the Carnegie Institution. Garrison and colleagues overview the use of lidar survey methods in the Maya region, highlighting how Maya archaeology has aided progress in physical geography. [Extracted from the article]

This paper reviews the history of remote sensing for mapping ancient Maya wetland fields in Central America and provides a new assessment using machine learning with LiDAR data. We evaluate past uses of radar, multispectral, and LiDAR datasets in Northwest Belize across well-studied wetland field complexes that occur under different vegetation conditions. Next, we compare topographic products derived from LiDAR data commonly used for archaeology and geomorphology. Lastly, we train a machine learning algorithm to detect ancient canals with LiDAR data and test the algorithm on a newly rediscovered field system. The spatial resolution of any dataset must be sufficiently high (2-m or finer resolution) to detect most of these canals reliably. High resolution multispectral sensors can detect canals in open areas, but most wetland complexes are under dense tropical forest impenetrable to multispectral instruments. LiDAR data were the most useful due to the high spatial resolution (0.5-m) and the ability to penetrate canopy, but still have limitations under certain conditions. The intensity of the LiDAR returns with multispectral LiDAR systems can reveal differences in soil and vegetation between ancient canals and fields in places leveled by modern farmers. The algorithm successfully maps ancient canals but has many false positives in natural depressions and drainages. Although the machine learning approach tested here cannot be used on its own, we used it with the LiDAR visualizations to refine the canal estimates from previous studies, mapping nearly 50% more canals in the Central Rio Bravo floodplain than originally published. [ABSTRACT FROM AUTHOR]

Studies of recent decades have shown thousands of kilometers of transportation networks that have presented damage or failure from different types of flows, causing important traffic disruptions. Debris flows running adjacent (or in parallel) to river channels often explain the structural damage to road embankments caused by slope erosion. The probability of expected structural damage caused by a natural hazard may be modeled using fragility curves, which have been developed for transportation infrastructures like bridges and roads exposed to debris flows and are used in risk assessment. There are even fragility curves available to estimate the fragility of road embankments exposed to perpendicular debris flows. However, currently no model is available to estimate the road damage probability of embankments exposed to adjacent debris flows despite their important effects on traffic. This paper aimed to develop fragility curves for road embankments exposed to adjacent debris flows, considering mechanisms of exposed slopes subject to erosion and subsequent embankment instability. Models were calibrated considering flow characteristics in straight and bend channels including three damage states in terms of road traffic capacity loss. Monte Carlo simulations were performed to model potential damage, obtaining fragility curves for two types of roads. Curves were fit to log-normal distributions with a 99.5% confidence level. The analysis demonstrated that the geometric characteristics of road embankments explain their fragility, wherein lower heights and platform widths result in more probable expected damage. The analytical model developed confirmed that the erosive process intensifies in bend zones of channels, resulting in higher damage probability. [ABSTRACT FROM AUTHOR]

Soil wind erosion is a global problem that leads to increasingly serious regional land degradation, where the need for windbreak and sand fixation services (WSFS) is substantial. Inner Mongolia plays an important role in global semiarid and arid areas and the severe land degradation resulting from soil wind erosion warrants an urgent solution. However, the mechanism of influence of various driving factors on windbreak and sand fixation services is still not fully studied. In this paper, the revised wind erosion equation (RWEQ) model was used to synthesize the monthly spatiotemporal dynamics of soil wind erosion modulus (SWEM) and WSFS in Inner Mongolia from January 2000 to February 2020 from a semi-monthly scale. The influencing factors of WSFS were examined from both natural and anthropogenic aspects. Results show that over the past 20 years, the average SWEM in Inner Mongolia was 118.06 t ha−1 yr−1, the areas with severe wind erosion were mainly concentrated in the desert areas in the southwest of Inner Mongolia, and the forests in the northeast suffered less soil wind erosion. Meanwhile, the average WSFS was 181.11 × 108 t yr−1, with the high-value areas mainly located in major deserts, sandy land, and the area bordering Mongolia in the north and the low-value areas mainly located in the densely forested northeast and the Gobi Desert in the northwest. Both SWEM and WSFS showed a clear downward trend and a certain periodicity over the past 20 years. WSFS showed two peaks a year (April and October). Among the natural factors, precipitation and NDVI showed a significant correlation with WSFS and were identified as the main driving factors of WSFS, whereas temperature had no significant correlation. Among the anthropogenic factors, farming and animal husbandry intensity and GDP showed a positive correlation with WSFS, whereas population showed a negative correlation. These four types of factors were identified as socio-economic factors that drive WSFS. Meanwhile, WSFS did not show any significant correlation with the administrative area. Land use change contributed to a large proportion of WSFS change, thereby suggesting that the intensity of human activities is another central driver of WSFS. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to develop an approach to estimate peat accumulation rates (PAR) over recent decades based on the age and burial depths of roots from pine sapling and to use the newly developed approach to estimate spatial variations of PAR. To this end, we sampled 120 pine saplings growing in three plots at Rėkyva peatland in Lithuania and accounted for the microtopography around each specimen. In the lab, all saplings were cut into 1-cm segments, sanded and analysed. The counting of annual rings allowed dating the germination of each sapling with a yearly resolution and thus also enabled estimation of peat accumulation. The latter was derived by measuring the distance from the original root collar at germination to the ground level (or peat surface) at the time of sampling. The large number of samples selected from three plots also enabled determination of spatial variations in PAR. We obtain averaged PAR values of 1.6 ± 0.72 cm yr−1 across the three plots and over the last decades, but also observe strong spatial heterogeneity in PAR resulting from differences in local hydrology and vegetation. To validate the results, we compared tree-ring derived PAR with radiocarbon-based (14C) estimates at one of the plots. The results are consistent between the two approaches with PAR estimated to 0.8 and 0.79 cm yr−1, respectively, over the last 20 years. We conclude that PAR can be assessed accurately with tree-ring approaches and that they have clear advantages over radiocarbon dating for shorter timescales as they can be replicated more easily. For longer timescales and larger depths (> 15 cm), however, 14C dating remains the preferred approach. [ABSTRACT FROM AUTHOR]

In this paper, the legacy of Kenneth Mason (1887–1976) in the geography of the Himalaya-Karakoram (H-K) region has been thoroughly examined. Mason was a distinguished British geographer, surveyor, soldier, and mountaineer. He led the Indo-Russian Triangulation Connection and pioneered the use of stereoscopic photography in the Pamirs, laying the groundwork for precise geographical records. His detailed surveys and mappings of the Shaksgam Valley and Aghil Ranges corrected longstanding cartographic inaccuracies and presented accurate topographical details through terrestrial stereo photogrammetry. Mason critically assessed and recommended improvements for the depiction of glaciers and geomorphic features on Survey of India maps, encouraging the training of surveyors in glacial morphology. He contributed significantly to standardising geographical terms and nomenclature within the Karakoram Range. Mason also played a crucial role in founding the Himalayan Club and the Himalayan Journal. His studies on glacier movements and advocacy for monitoring systems to prevent natural disasters exhibit his profound commitment to minimising human life and infrastructure loss. Mason’s comprehensive work boosted scientific investigation in the H-K region and laid a foundation for ongoing and future research in these remote regions, paving the way for future generations of explorers, researchers, and enthusiasts. [ABSTRACT FROM AUTHOR]

Water scarcity is a global issue, affecting in excess of four billion people. Interbasin Water Transfer (IBWT) is an established method for increasing water supply by transferring excess water from one catchment to another, water-scarce catchment. The implementation of IBWT peaked in the 1980s and was accompanied by a robust academic debate of its impacts. A recent resurgence in the popularity of IBWT, and particularly the promotion of mega-scale schemes, warrants revisiting this technology. This paper provides an updated review, building on previously published work, but also incorporates learning from schemes developed since the 1980s. We examine the spatial and temporal distribution of schemes and their drivers, review the arguments for and against the implementation of IBWT schemes and examine conceptual models for assessing IBWT schemes. Our analysis suggests that IBWT is growing in popularity as a supply-side solution for water scarcity and is likely to represent a key tool for water managers into the future. However, we argue that IBWT cannot continue to be delivered through current approaches, which prioritise water-centric policies and practices at the expense of social and environmental concerns. We critically examine the Socio-Ecological Systems and Water-Energy-Food (WEF) Nexus models as new conceptual models for conceptualising and assessing IBWT. We conclude that neither model offers a comprehensive solution. Instead, we propose an enhanced WEF model (eWEF) to facilitate a more holistic assessment of how these mega-scale engineering interventions are integrated into water management strategies. The proposed model will help water managers, decision-makers, IBWT funders and communities create more sustainable IBWT schemes. [ABSTRACT FROM AUTHOR]

Fractal geometry methods provide a quantitative description of complex landscape networks, such as drainage patterns. This article focuses on the determination of the fractal dimension (F D ) and Renyi multifractal spectrum (F Dα ) of drainage patterns of the Blue Nile Basin in the Ethiopian Highlands. The Ethiopian Highlands are one of the most tectonically influenced areas in the world. The spatial distribution of drainage patterns reflects a decreasing influence of tectonics with increasing distance from the Main Ethiopian Rift (MER) to the center of the Ethiopian Highlands. The novelty of the paper is given by the calculation of F D and F Dα of drainage patterns as a part of morphostructural analysis. We analyzed how the values of F D and F Dα in each of 145 local drainage patterns changed depending on the changes of tectonic influences on landscape formation. Our methodologies provided a way of distinguishing the morphologies of tectonic and non-tectonic drainage patterns using the fractal/multifractal technique. The results of the study show that old dendritic drainage patterns located in the western part with low tectonic activity and an absence of faults had the lowest F D and F Dα values. The opening up of the MER and the neotectonic uplift of the Ethiopian Highlands accelerated the development of drainage patterns by activating river erosion and river piracy. Dendritic drainage patterns of the volcanic platforms have changed to young deep cut trellis patterns, and their F D and F Dα values are increased. Accelerating Quaternary uplift created the recent high landscape in the eastern part of the Blue Nile Basin, where the tectonic activities correspond to the MER. This young Quaternary landscape is characterized by prevailing deep and narrow valleys, and the presence of morphodynamic phenomena (erosion, landslides, earthquakes), where the trellis drainage patterns have the highest F D and F Dα .values. [ABSTRACT FROM AUTHOR]

This Classics Revisited/From the Archives paper summarizes the 1962 publication of Robert Kates regarding perceptions of the flooding hazard in LaFollette, Tennessee, and five other cities that were used for comparison. The influence of this work on improvements in flood hazards since 1962 are discussed, as well as suggestions as to how this work will continue to influence flood hazard management and mitigation. [ABSTRACT FROM AUTHOR]

Water shortage has plagued the social development and human well-being of global closed basins. However, the hydroclimate research on different time scales in these regions remains inadequate at a global scale. In this paper, the hydrological responses from global closed basins to millennial-scale and centennial-scale cold/warm events since the Last Glacial Maximum were explored. Closed-basin lake records indicate that the westerlies-dominated closed basins are generally wetter during cold events than the corresponding warm ones on the millennial and centennial scales. In contrast, the monsoon-influenced closed basins prevail wetter climates during warm events. According to the hydroclimate simulations, precipitation seasonality plays a significant role in causing above spatial–temporal patterns. There is more winter rainfall in westerlies-dominated closed basins during cold events in the Last Glacial Maximum and Little Ice Age and more summer rainfall in monsoon-influenced closed basins during warm events in the mid-Holocene and Medieval Climate Anomaly. Under modern and future global warming, the hydroclimate changes in global closed basins show more regional differentiation, resulting in wetter mid-latitude Asian and low-latitude African closed basins but drier southwest North American and Australian closed basins. [ABSTRACT FROM AUTHOR]

Traditional monitoring (e.g., in-water based surveys) of eelgrass meadows and perennial macroalgae in coastal areas is time and labor intensive, requires extensive equipment, and the collected data has a low temporal resolution. Further, divers and Remotely Operated Vehicles (ROVs) have a low spatial extent that cover small fractions of full systems. The inherent heterogeneity of eelgrass meadows and macroalgae assemblages in these coastal systems makes interpolation and extrapolation of observations complicated and, as such, methods to collect data on larger spatial scales whilst retaining high spatial resolution is required to guide management. Recently, the utilization of Unoccupied Aerial Vehicles (UAVs) has gained popularity in ecological sciences due to their ability to rapidly collect large amounts of area-based and georeferenced data, making it possible to monitor the spatial extent and status of SAV communities with limited equipment requirements compared to ROVs or diver surveys. This paper is focused on the increased value provided by UAV-based, data collection (visual/Red Green Blue imagery) and Object Based Image Analysis for gaining an improved understanding of eelgrass recovery. It is demonstrated that delineation and classification of two species of SAV (Fucus vesiculosus and Zostera marina) is possible; with an error matrix indicating 86–92% accuracy. Classified maps also highlighted the increasing biomass and areal coverage of F. vesiculosus as a potential stressor to eelgrass meadows. Further, authors derive a statistically significant conversion of percentage cover to biomass (R 2 = 0.96 for Fucus vesiculosus, R 2 = 0.89 for Zostera marina total biomass, and R 2 = 0.94 for AGB alone, p < 0.001). Results here provide an example of mapping cover and biomass of SAV and provide a tool to undertake spatio-temporal analyses to enhance the understanding of eelgrass ecosystem dynamics. [ABSTRACT FROM AUTHOR]

The temporal variability in sediment export yield from glaciers over a timescale of multiple glacial cycles (e.g. 1 × 102 − 1 × 106 years) is of interest for a wide range of applications in glaciology, sedimentology, geomorphology, climatology and environmental engineering. However, the time required for the products of glacial erosion to be transferred through glaciated catchments and the extent to which glacially-conditioned sediment can be transiently stored within them are still poorly constrained and a matter of debate within the community. We propose a conceptual model of the variability in sediment exported from glaciers over multiple glacial cycles based on a literature review. Sediment yield is likely to be highly variable through a glacial cycle, notably between phases of glacier advance, retreat and re-advance due to changes in ice velocity and erosion rates, ice and meltwater transport capacity, and in glacially-conditioned sediment accessibility at the bed. Typically, early phases of glacier retreat and re-advance are expected to lead to the highest increase in sediment yield due to the ease with which the products of bedrock erosion can be accessed and reworked. In contrast, later phases of glacial (re)advance, once glacially-conditioned sedimentary sources become exhausted, may be characterized by intermediate rates of sediment export yield maintained through bedrock erosion. The latest phases of deglaciation, once glacially-conditioned sedimentary sources are either exhausted, stabilized or disconnected from active processes of sediment transfer, are likely to have the lowest rate of export. The conceptual model proposed in this paper fills a gap in the literature by developing a continuous pattern of sediment yield rate variability over the course of multiple glacial cycles, with wider implications for future research. However, its systematic applicability to various glacier settings and glaciations needs more field and modeling data to validate it. [ABSTRACT FROM AUTHOR]

Natural flood management (NFM), or working with natural processes, is a growing flood risk management method in the UK, Europe and worldwide. However, unlike the current dominant technical flood management, it lacks an established evidence base of flood risk parameters. This lack of evidence base can limit the uptake of NFM as a flood management method. This paper critically evaluates examples of NFM and wider relevant literature in order to identify NFM knowledge gaps and suggest how to overcome these. The UK is used as a microcosm of different environments for diverse examples. The sections include: land cover, land management, landscape interactions and trade-offs, evaluating the wider benefits of NFM and, finally, scaling from plot to catchment. This concludes in a suggested framework for a new approach to NFM research, which encompasses spatial scales, interactions and trade-offs of NFM and consistency of reporting results. Widening the NFM empirical evidence base should be seen as an opportunity for a new approach to flood research through exploring new habitats and new flood resilience methods. [ABSTRACT FROM AUTHOR]

Our understanding of the Martian atmosphere, terrain and subsurface has continuously evolved over the past couple of decades as a result of a number of successful orbiter and rover missions. This prompts a need to revisit the first holistic review of Martian geomorphology, based on images from the Viking orbiters, by Victor R. Baker in 1981. Several of the interpretations and recommendations based on remote sensing in Baker's paper are as valid today as they were four decades ago. With an unprecedented focus on Mars exploration in the coming decades, it is important to revisit the advances and prospects in Martian geomorphology research. [ABSTRACT FROM AUTHOR]

The Asian Alpine Belt (AAB) region extends from the Tibetan Plateau to the Caucasus. Rapid climate change and increasing anthropogenic pressures in the ecologically sensitive alpine area are making the achievement of sustainable development goals in the AAB more challenging. The water--food--energy--ecosystem (WFEE) nexus describes the trade-offs and synergies among the various elements of water, food, energy resources, and natural ecosystems relevant for sustainable development. The optimization of the WFEE nexus in the AAB region has become a vital issue for reaching sustainability in this ecologically fragile Eurasian region and its developing countries. In this paper, we broadly classify research into four types based on a compilation of recent research on the WFEE nexus in the AAB region: ecohydrological processes, agriculture and livestock, clean energy, and local social adaptation. We use the classification--coordination--collaboration approach to build an optimized conceptual framework to indicate a future research path. The outlook includes enhanced identification of the WFEE nexus, scientifically rational decision-making, and attention to cross-sector and transnational collaboration to support the realization of sustainable development goals in the AAB region. [ABSTRACT FROM AUTHOR]

The publication of Fenneman's two volumes on physiography: The Physiography of Western United States and the Physiography of Eastern United States, was the culmination of over 20 years of work toward formalization of the physiographic regions in the United States. This paper details the relevant works that predate these volumes, the two volumes themselves, as well as briefly describing Fenneman's career and the continued use of the works 80 plus years post-publication. [ABSTRACT FROM AUTHOR]