bluuebunny/crossref_metadata_2025 huggingface dataset:
Subglacial landforms reveal basal ice flow patterns of the Last Glacial Maximum Rhine glacier
Authors: Kamleitner Sarah , Ivy-Ochs Susan , Salcher Bernhard , Reitner Jürgen M.
Published: February 2023

We present new insights into the ice flow dynamics of the Last Glacial Maximum (LGM) Rhine glacier based on a comprehensive inventory of glacially streamlined bedforms. High-resolution LiDAR data was used to map ice-marginal moraines and more than 2500 subglacial landforms located in the ~6000 km2-sized footprint of the former piedmont lobe. Orientation and morphometry of mapped bedforms were subsequently used to deduce paleo ice flow lines. Most of the subglacial landforms in the dataset are drumlins, but glacial lineations and subglacial ribs (Rogen/ribbed moraines) are also present in the study area. Streamlined bedforms predominantly occur in fields internal to the frontal moraine set of the inner (Stein am Rhein ice margin) of two LGM ice marginal complexes (Kamleitner et al., 2023). We interpret these landforms to have been shaped isochronously during the late LGM readvance (Kamleitner et al., 2023; Schreiner, 1992) to and the active stabilization at the Stein am Rhein ice marginal position. Deviating drumlin orientations (e.g. cross-cutting relationships) are rare within the Stein am Rhein flow set, supporting the hypothesis of contemporaneous formation. Bedform orientations of this flow set are the basis for inferring the ice flow patterns during the Stein am Rhein stadial. Continuous fields of flow are interpolated by applying the recently presented kriging approach of Ng and Hughes (2019). The reconstructed directions show radial ice flow emanating from the mouth of the confined Alpenrhein Valley that fans out towards the Stein am Rhein frontal moraines. Flow lines converge due to compression in narrow valley sections and diverge around topographic highs. Basal ice flow during the late LGM Stein am Rhein readvance was strongly controlled by topography. Derived paleo flow lines are combined with information from bedform elongation that allows to confine potential areas of relatively fast flowing ice. We find these to largely overlap with known overdeepenings, in line with predictions from numerical simulations (Cohen et al., 2018).
An Introduction to NASA’s Catalog of Archived Suborbital Earth Science Investigations (CASEI)
Authors: Wingo Stephanie , Smith Deborah , Davis Carson , Bagwell Shelby , Mok Heidi , Keeble Edward , Feldmann Tammo , Lukach Anthony , Ruehl Alice , Woods Camille , Shirey Ashlyn , Walker Elijah , Ramachandran Rahul
Published: February 2023

NASA’s Airborne Data Management Group (ADMG) works to promote and ensure the discoverability and accessibility of over 50 years of non-satellite Earth science observations. This includes leading the development of the Catalog of Archived Suborbital Earth Science Investigations (CASEI), which provides a single entry point to efficiently search across all of NASA’s airborne and field data holdings.  CASEI supports NASA’s Open Source Science Initiative vision by providing holistic, descriptive contextual metadata and links to streamline access to suborbital data products, regardless of which repository is responsible for their stewardship.Metadata in CASEI includes descriptive contextual details that are typically arduous to locate amid a synthesis of scattered publications, project and program websites, and disparate data discovery tools. These metadata include motivating science objectives, key events/time periods in observational records, complementary simultaneous observations, and programmatic details, among others. Diversity of data formats and science disciplines served by CASEI necessitate a common data model to organize suborbital observation metadata and appropriately represent the relationships among campaigns, platforms, and instruments.This presentation will describe the development of the CASEI system: well-defined data models to drive a cloud-based user data access portal, simultaneously provisioned interfaces enabling synchronous metadata updates, the curation process required to sustain this unique inventory of airborne and field metadata, management of CASEI information content, and connecting end users to data products relevant for their interests - regardless of which NASA distributed archive center holds the data.Particular attention will be granted to how CASEI facilitates discovery and (re)use of these lesser-known NASA data, supporting FAIR principles and Open Science to enhance the return on investments made in these unique and varied observations. An up-to-date summary of CASEI inventory content, avenues for CASEI enhancements, and potential improvements in suborbital data stewardship at various stages of the data life cycle will also be discussed.
A key for education towards the Agenda 2030 Goals: the integration among geosciences, biology and chemistry.
Authors: Furfori Ilaria
Published: February 2023

One of the three main thematic groups of Civic Education, introduced in Italian schools since September 2020, is "Sustainable development, environmental education, knowledge and protection of heritage and the territory". This thematic group allows me to develop the issues related to geosciences in the 2030 Agenda with an interdisciplinary approach in upper secondary school, an aspect that I am facing during my PhD.One of the activities that I will propose to a class according to a horizontal approach will be centered on GOAL 15 and is entitled "Integrating geodiversity and biodiversity towards the Agenda 2030 goal 15 -Life on Earth": the path will take about 6 hours and one or two educational outings in the area. In these lessons students will explore the differences between two natural environments i.e. mountain and coastal, appropriate sites nearby my school are the: Botanical Garden of the Apuan Alps  “Pellegrini - Ansaldi” and Massaciuccoli lake. The classes involved could be third or second classes and the degree of in-depth study of the disciplines will be declined accordingly. The activities will directly involve the students using brainstorming and laboratory activities (geological maps of the study areas will be used and rock samples will be investigated), the educational outings will be useful precisely to verify in the field whether there is a correlation between geodiversity and biodiversity. The theme of desertification as a consequence of both biological and geological environmental impoverishment will also be addressed to make people reflect on how this has an impact on the people involved and on the impacts that desertification has on the other SDGs.Within the poster I will present one of the projects that I intend to propose to schools as part of my PhD which concerns precisely identifying points of integration between the different subjects that make up the subject of teaching, i.e. the Natural Sciences with the aim of making students more aware of Earth Sciences issues.
Spatial and Temporal Evolution of Drought Events Using High-Resolution SPEI and Dynamic Drought Detection Algorithm
Authors: Yoo Jiyoung , Kim Jiyoung , Kwon Hyun-Han , Kim Tae-Woong
Published: February 2023

Drought is one of the world's major natural disasters. In order to monitor drought and reduce drought damage through preemptive response, it is important to understand the spatiotemporal evolutionary characteristics of drought. Droughts have a three-dimensional (3-D) space-time structure, typically spanning hundreds of kilometers and lasting months to years. In this study, a high-resolution(5 km) SPEI-HR(Standardized Precipitation Evaporation Index) dataset was used, considering climatic (typical temperate continental climate) and various geographic characteristics (mountainous terrain, lowland basin, desert, grassland, etc.). In addition, all large- and small-scale drought events that evolve spatiotemporally were extracted using the dynamic drought detection technique (DDDT) algorithm. These 3D-drought properties are important information to explain the spatiotemporal evolution of drought and are characterized by drought patches in dynamic drought maps. As a result, most of the trajectories of droughts in Central Asia during the period 1981 to 2018 tended to move laterally to the east and west (ENE, E, ESE, WNW, W, WSW). In addition, droughts in Central Asia are characterized by very strong correlations between indicators of duration, severity, area, and trajectory movement distance. These Central Asian drought characteristics are interpreted as meaning that there is consistency among various drought information in determining the most severe drought event. In addition, the dynamic drought map, which includes all 3D-drought properties, has the advantage of producing high-level drought information (temporal continuity of drought events and dynamic evolution characteristics, etc.) that are not found in general drought maps through various conditional drought monitoring.Acknowledgements: This work was supported by the National Research Foundation of Korea (No. NRF-2020R1C1C1014636) and Korea Environment Industry & Technology Institute (KEITI) (No.2022003610001) funded by the Korean government (MSIT and MOE).
Future changes in runoffs in the headwaters of the Tarim River
Authors: Fang Gonghuan , Chen Yaning
Published: February 2023

The Tarim River Basin, situated in the Eurasia hinterland, serves as the heart of China’s Silk Road Economic Belt. It covers an area of 1.02 million km2 and is surrounded by the Tienshan Mountains to the north, the Kunlun Mountains to the south and the Pamir to the west. The runoff is recharged by glacier melt, snow melt, and rainfall. There are large amount of glaciers distributed in the high mountains of Tienshan and the Kunlun Mountains. In recent decades, the glaciers in the Tienshan Mountains are retreating at a faster rate, while glacier in the Kunlun Mountains show less retreat or even advancing trend (i.e., Karakorum anomaly). These changes in glaciers will definitely alter the future runoff.This study extended the hydrological model SWAT-Glacier by incorporating a degree-day based glacier melt and accumulation module. The hydrological processes of the headwaters of the Tarim River were simulated using SWAT-Glacier model. The model was calibrated and validated using multiple variables, including glacier mass balance, snow cover area, snow water equivalent, daily streamflow and the balance between snowfall, snow melt and sublimation. The hydrological model was forced by the bias-corrected climate from 6 regional climate models in CORDEX. Results indicated that the runoffs of the headwaters originated from the south Tienshan Mountains (i.e., Kaidu River, Aksu River) demonstrated a slight increase or even decrease trend. For the Kaidu River, there will be a slight decrease in runoff under SSP585, as the contribution of glacier melt water is less than 10%. For the Kumarak River, the runoff showed slightly increase and the glacier melt runoff will reach peak point before 2050s. For the rivers originated from the north Kunlun and Karakorum Mountains, the runoff will increase dramatically.This study provide a basin-scale runoff changes under multiple constraints in the endoreic Tarim River Basin. However, the glacier accumulation and ablation suffers from great uncertainty as the precipitation observation is rare in the high mountains. More efforts should be taken to utilize more state-of-the-art technology in revealing the meteorological and hydrological processes in these alpine catchments.
Changes and mechanisms of long-lived warm blobs in the Northeast Pacific in low-warming climates
Authors: Shi Jian , Tang Cong , Zhang Yu
Published: February 2023

In the last decade, three persistent warm blob events (2013–2014, 2015, and 2019–2020) in the Northeast Pacific (NEP) have been hotly debated given their substantial effects on climate, ecosystem, and socioeconomy. This study investigates the changes of such long-lived NEP warm blobs in terms of their intensity, duration, structure, and occurrence frequency under Shared Socioeconomic Pathway (SSP) 119 and 126 low-warming scenarios of the Coupled Model Intercomparison Project Phase 6. Results show that the peak timing of the warm blobs shifts from cold season to boreal summer. For the summer-peak warm blobs, their maximum intensity increases by 6.7% (10.0%) under SSP119 (SSP126) scenario, but their duration reduces by 31.0% (20.4%) under SSP119 (SSP126) scenario. In terms of their vertical structure, the most pronounced temperature signal is located at the surface, and their vertical penetration is mostly confined to the mixed layer, which becomes shallower in warming climates. Based on a mixed-layer heat budget analysis, we reveal that shoaling mixed layer depth plays a dominant role in driving stronger intensity of the warm blobs under low-warming scenarios, while stronger magnitude of ocean heat loss after their peaks explains the faster decay and thus shorter duration. Regarding occurrence frequency, the total number of the warm blobs does not change robustly in the low-warming climates. Following the summer peak of the warm blobs, extreme El Niño events may occur more frequently under the low-warming scenarios, possibly through stronger air-sea coupling induced by tropical Pacific southwesterly anomalies.
The Influence of Temperature on the Fall of the Guge Kingdom in Western Tibet, China
Authors: Xie Haichao , Liang Jie
Published: February 2023

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) from lacustrine sediments have been widely used to reconstruct mean annual air temperature (MAAT). Although many proxy calibrations relating brGDGT characteristics have been put forth, these calibrations may produce warm biases when applied to lakes in cold regions. We present an expanded Chinese lake surface sediment brGDGT-MAAT calibration with 29 new surface samples from cold regions along with 39 previously published from Chinese lakes. We deployed sediment traps in a meromictic lake, Dagze Co, and compared results with previously published data from a dimictic lake, Lake 578 in Greenland, to determine potential seasonal and depth-dependence of brGDGTs. In the meromictic lake, brGDGTs are primarily produced in the lake bottom water, whereas in the dimictic lake, the brGDGTs are produced throughout the water column and mainly reflect the annual bottom water temperature or mixing season water column temperature. We applied our refined calibration to a sediment core from Western Tibet to examine how fluctuations in temperature influenced the Guge Kingdom over the last 2,000 years. Our record reveals relatively warm temperatures during the Medieval Climate Anomaly, cooling of 2°C to -2°C during the Little Ice Age, warming into the eighteenth century, and stabilization after 1800 CE. The temperature variations coincided with a transition of dynasties in Western Tibet. Temperature sensitivity tests on barley distribution, the principal cultivated cereal in Tibet, suggest that a decline in temperature led to a decreased crop yield that may have factored into the disappearance of the Guge Kingdom.
Fluctuations of snow depth before AMeDAS in the foothill area of the Northern Japan Alps
Authors: Suzuki Keisuke
Published: February 2023

Meteorological observations by the Japan Meteorological Agency were made at points called local observatories in addition to meteorological stations, until the AMeDAS (Automated Meteorological Data Acquisition System) went into operation. At the local observatories, individuals and government offices entrusted by the Japan Meteorological Agency were observing manually. The total number of local observatory was larger than the number of observation points of the current AMeDAS, but due to the limitations of the uniformity of the accuracy of the observation data and the reporting speed, it was updated to the current AMeDAS. Since the foothill area of the Northern Japanese Alps is known as a heavy snowfall area, snow depth has been observed for a long time. Meteorological observation records at local observatories, are kept as a handwritten original book. We collected it as image data, read the data from the image and input it again as numerical data, and analyzed the fluctuation of the snow depth before the AMeDAS observation in the foothill area of the Northern Japan Alps. The observation period is different for each of the five points where the snow depth was observed for more than 20 years, but there is no tendency for the annual maximum snow depth to increase or decrease at any of the points. The winter temperature in heavy snow years is low, and the winter temperature in light snow years is high.
Evaluation of the Effect of Place Attachment and Perceptions of Living Environment on Disaster Preparedness: A Case Study in Nagano, Japan
Authors: Terakawa Koki , Tsuyoshi Takano Tsuyoshi , Nakai Fuko , Otsuyama Kensuke , Nakamura Shinichiro
Published: February 2023

Natural disaster preparedness has a significant impact on the magnitude of disasters and damages. Previous studies on disaster preparedness have focused mainly on promoting risk perception by providing disaster information, but this does not have a sufficient mitigating effect because people who are less concerned about disasters have less access to the information. Since disaster preparedness is considered to be defined not only by risk perception but also by the perception of the living environment, it is important to evaluate disaster preparedness mechanisms that take into account the perception of the living environment. On the other hand, Previous studies have pointed out that place attachment promotes preparedness for natural disasters. Therefore, this study investigated the effect of place attachment and the perception of living environment, which is also a factor in the formation of place attachment, on preparedness in Nagano City, Nagano Prefecture, Japan. A web-based survey asked about sociodemographic characteristics, perception of living environment, place attachment, and preparedness being implemented, and 1,000 people answered the survey.The Structural Equation Modeling (SEM) performed on the results of the survey revealed that living environment prompts preparedness, and that the structure of preparedness varies with individual attributes. Furthermore, even if there is no direct relationship (path) from living environment to preparedness, it was found that there are factors that have an indirect effect through place attachment. On the other hand, there were also factors whose indirect effects turned negative when mediated by place attachment. Thus, the results indicate that some factors improve disaster preparedness through place attachment, while others decrease it.These results suggest that for individuals with personal attributes for whom promoting risk perception alone does not lead to improved preparedness, perception of the living environment and place attachment could lead to improved preparedness. Since the target sites include flood-prone areas, it is possible that the social - environmental perceptions of the residents here might diverge from the general perceptions. Therefore, future case studies should be conducted in other areas to explore more general factors.
Discharge and extension of debris flow and its application to ocean environments in South Pacific Area
Authors: Kim SoungDoug , Lee Hojin , Chang Hyungjoon
Published: February 2023

The purpose of this present study is to investigate and analyze the extension and the effect of debris flow generated in mountainous terrain due to climate change on the coastal and ocean downstream areas. As the target area of this study, the coast of Fiji in the South Pacific region affected by super hurricanes every year was selected. The category 5 Hurricane Winston in 2016 produced 42,700 tons of debris flow and caused massive damage to the entire Fiji. For debris flow analysis, mass conservation and momentum conservation equations were used as governing equations, and the finite difference method was applied to the numerical model. As a result of the analysis, the increase in the discharge of debris flow generated in the upstream mountainous area and the increase of the flow water depth extend along the downstream river to the Pacific coast, and a lot of soil run out. To check how far the debris flow moves along the river, the diffusion length of the debris flow was calculated, and the debris flow spreads over a considerable range during heavy rain. Corresponding author: Hojin Lee(hojin@chungbuk.ac.kr)
A New Multi-Mission Sea Surface Salinity Optimum Interpolation (OISSS) Analysis for Ocean Research and Applications
Authors: Melnichenko Oleg , Hacker Peter , Potemra James , Meissner Thomas , Wentz Frank
Published: February 2023

We introduce a new version of the multi-mission sea surface salinity (SSS) optimum interpolation analysis (OISSS) which combines observations from NASA’s AQUARIUS/SAC-D and SMAP (Soil Moisture Active-Passive) satellite missions into continuous and consistent SSS data record. The dataset covers the period from September 2011 to present. Measurements from ESA’s SMOS (Soil Moisture and Ocean Salinity) satellite are used to fill gaps in SMAP observations during June-July 2019 and August-September 2022, when the SMAP satellite was in a safe mode and did not deliver scientific data. The analysis is based on Optimum Interpolation (OI), utilizes Level-2 (swath) data, and uses satellite-specific bias-correction algorithms to correct the satellite retrievals for large-scale biases.  The dataset includes uncertainty estimates, both formal and empirical. We use this dataset as an example to discuss requirements for the multi-mission SSS data products.To demonstrate its utility, the new dataset is used to characterize spatial patterns of SSS variability in the global ocean and on different time scales. The spatial pattern of the regional SSS trends show that the subtropical North Pacific is becoming fresher while the subtropical South Indian Ocean is becoming saltier. This is seemingly a part of a longer term oscillation as the trends are reversed compared to the preceding decade (2005-2015) estimated from Argo data. In particular, abrupt changes occurred during 2015, related, presumably, to a strong El Nino event of 2015-2016. The annual cycle is a dominant signal globally and can nicely be described by two leading empirical orthogonal functions (EOFs) explaining more than 35% of the total SSS variance. Except for the Indian Ocean, the oscillations are out of phase in the Northern and Southern Hemispheres and describe poleward propagation away from the Equator driven, presumably, by Ekman dynamics. The intra-seasonal signal is strongest in the tropics, particularly in the quasi-zonal bands associated with the Inter-tropical convergence zone (ITCZ) and South Pacific convergence zone (SPCZ), but also near outflows of major rivers, including the Amazon, Congo, Mississippi, Plata, Ganges and Brahmaputra.  Another region of interest is the northern North Atlantic, where satellite observations during the last decade have provided an unprecedented resource to study the spatial distribution and temporal evolution of SSS, allowing to observe areas typically not available by in-situ components of the ocean observing system. Here, the multi-mission SSS dataset is examined in its accuracy and appropriateness for studying SSS variability in high latitudes and marginal seas. 
Mesoscale eddy parameterisation in numerical "grey zone" ocean models
Authors: Mak Julian , Maddison James , Marshall David , Ruan Xi , Yan Wang
Published: February 2023

It is known that ocean models at eddy permitting horizontal resolutions, while being the target for the next generation Earth System Models, suffer from several known deficiencies that lead to rather significant biases in the physical response particularly in the Southern Ocean. One cause of such deficiencies is attributed to the weak mesoscale eddies that are permitted, leading to weaker feedbacks onto the large-scale ocean circulation, with resulting consequences for other components of a Earth System Model. Without a parameterisation active, the eddy feedback is too weak and under-counted, but if a parameterisation is active then there is a double-counting issue, and explicit eddies may be severely damped by the parameterisation. Two existing approaches are to employ a resolution function, or to accept the damping introduced by the parameterisation but backscatter some energy/momentum into the modelled flow in some way.Here we propose an alternative approach that reduces the damping of explicit eddies by the parameterisation in the first place, and instead of a resolution function asks for a definition of the "large-scale" state. We test the procedure in an idealised channel and gyre model in NEMO 4.0.5, in combination with the GEOMETRIC parameterisation for the eddy induced advection. Impacts to the explicitly resolved variability, total (explicit and parameterised) eddy energy levels, modelled mean state and its sensitivity, as well as biogochemical responses are discussed.(Sample output: see https://imgur.com/ifM1SPQ for full resolution images. Showing surface relative vorticity, for (a) no parameterisation, (b) standard GM parameterisation applied as is, (c) GEOMETRIC applied as is, (d) GEOMETRIC applied in the new way.)
Observation-based global soil heterotrophic respiration indicates underestimated turnover and sequestration of soil carbon by terrestrial ecosystem models
Authors: He Yue , Ding Jinzhi , Dorji Tsechoe , Wang Tao , Li Juan , Smith Pete
Published: February 2023

Soil heterotrophic respiration (Rh) refers to the flux of CO2 released from soil to atmosphere as a result of organic matter decomposition by soil microbes and fauna. As one of the major fluxes in the global carbon cycle, large uncertainties still exist in the estimation of global Rh, which further limits our current understanding of carbon accumulation in soils. Here, we applied a Random Forest algorithm to create a global dataset of soil Rh, by linking 761 field observations with both abiotic and biotic predictors. We estimated that global Rh was 48.8 ± 0.9 Pg C yr-1 for 1982-2018, which was 16% less than the ensemble mean (58.6 ± 9.9 Pg C yr-1) of 16 terrestrial ecosystem models. By integrating our observational Rh with independent soil carbon stock datasets, we obtained a global mean soil carbon turnover time of 38.3 ± 11 yr. Using observation-based turnover times as a constraint, we found that terrestrial ecosystem models simulated faster carbon turnovers, leading to a 30% (74 Pg C) underestimation of terrestrial ecosystem carbon accumulation for the past century, which was especially pronounced at high latitudes. This underestimation is equivalent to 45% of the total carbon emissions (164 Pg C) caused by global land use change at the same time. Our analyses highlight the need to constrain ecosystem models using observation-based and locally adapted Rh values to obtain reliable projections of the carbon sink capacity of terrestrial ecosystems.
Analyzing Land Use/Land Cover Changes and its Dynamics Using Remote Sensing Data: A case study of Gabala, Azerbaijan
Authors: Ahadov Bahruz , Karimli Nilufar
Published: February 2023

To track global environmental change and evaluate the risk to sustainable development, analysts and decision-makers in government, civil society, finance, and industry need the fundamental geospatial data products known as Land Use and Land Cover Change (LULCC) maps. Our research studied LULCC variations in a timeframe of 5 years in the Gabala district. Sentinel 2 open-source products were used to compare and categorize the procedure over one-year time intervals. For this investigation, the discrete indexing method was developed and used. The approach we used was focused on obtaining multiple indices and using them to improve classification performance. The Normalized Difference Vegetation Index (NDVI), Modified Normalized Difference Water Index (MNDWI), Bare Soil Index (BSI), Normalized Difference Tillage Index (NDTI), and Salinity Index (SI) are the indices evaluated. The most crucial variables were determined and classified using the random forest classifier in LULCC. The Sentinel Application Platform of the European Space Agency (SNAP ESA) algorithm was used to analyze the process and performed over 90% accurate predictions when applied to the testing dataset. Results revealed that using the RS technique, time and cost-efficient analyses are possible and reliable for developing socioeconomic and ecological growth strategies.
Greening vegetation alleviates hot extremes in the semiarid region of China
Authors: Cao Yipeng , Guo Weidong , Ge Jun , Liu Yu , Chen Chaorong , Luo Xing , Yang Limei
Published: February 2023

China has shown a world-leading vegetation greening trend since 2000, which may exert biophysical effects on near-surface air temperature (SAT). However, such effects remain largely unknown because prior studies either focus on land surface temperature, which differs from SAT, or rely on simulations, which are limited by model uncertainties. As a widely used metric in climate and extremes research, SAT is more relevant to human health and terrestrial ecosystem functions. Therefore, it is necessary to explore impacts of greening on SAT and extremes based on observations. Here, we investigate the greening effects on SAT and subsequent extremes over 2003–2014 in China based on high-resolution SAT observations combined with satellite datasets. We find that greening can cause cooling effects on the mean SAT and more pronounced cooling effects on SAT extremes over semiarid regions. Such cooling effects are attributed to enhanced evapotranspiration caused by greening and strong coupling between evapotranspiration and SAT in semiarid regions. Semiarid regions in China are the transitional zone of both climate and ecosystem and deeply influenced by human agricultural and pastoral activities. These factors make the ecosystem of these regions fragile and extremely vulnerable to climate change. Our results reveal a considerable climate benefit of greening to natural and human systems in semiarid regions, and have significant implications for on-going revegetation programs implemented in these regions of China.
NW Iran under pressure: Cristallization and metamorphic ages of the Shanderman eclogites.
Authors: Pastor-Galán Daniel , Tsujimori Tatsuki , López-Carmona Alicia , Yi Keewook
Published: February 2023

The Tethyan oceans are the internal sotry-tellers of the amalgamation, tenure and break up of Pangea. All tethyan oceans have been mostly consumend and only remnants of them occur now along the margins of the Atlantic, Mediterranean, Black and Caspian seas, as well as in the Alpine-Himalayan and adjacent orogens. The Rheic (~500 to ~300 ma, some-times Ran or Proto-Tethys) closed during the amalgamation of Pangea and the Neo-Tethys (~270 to ~20 ma) is the main witness of its break-up. The Paleotethys is the ocean that shared an internal position during most of Pangea’s tenure. There is no consensus about its origin, some suggest that opened during the latest stages of Pangea’s amalgamation (Devonian-Carboniferous) whereas others considert it a remnant of the mostly subducted Rheic ocean after Gondwana-Laurussia collision.
We have studied the Shanderman eclogites (NW Iran) and put them into their context within other HP rocks in the area because they a potential candidate to represent the Paleotethys ocean. They are metamorphosed oceanic rocks (protolith oceanic tholeiitic basalt with MORB composition). Eclogite occurs within a serpentinite matrix, accompanied by mafic rocks resembling a dismembered ophiolite. The eclogitic mafic rocks record different stages of metamorphism during subduction and exhumation.
In this contribution we will show the new petrological, geochemical and geochronological results from this eclogites to shed light on the evolution of the tethyan oceans during the Paleozoic. The protolithic oceanic crust of Shanderman crystallized ~350 Ma, metamorphic age suggest that this piece of ocean subducted soon after forming, representing, perhaps, a subduction initiation or a ride-subduction event. We also found a metasomatic event at ~280 ma. Considering its relation with other HP rocks in Iran, we interpret that the Shanderman ophiolites are not a fragment of the Paleotethys but a fragment of the Rheic (Ran/Prototethys) ocean.
Understanding the origins of climate anomalies during low-yield years in Australia’s largest breadbasket
Authors: Li Hao , Keune Jessica , Gou Qiqi , Holgate Chiara , Miralles Diego
Published: February 2023

Wheat yield in Australia is highly dependent on year-to-year climate variability. Prolonged droughts and anomalously high temperatures have been considered as causes of agricultural failures in recent years. However, the origins of these climate extremes and their impacts on yield remain under study. Here, we use a Lagrangian trajectory model driven by atmospheric reanalysis data to delineate the source regions of moisture and heat over Australia’s largest rainfed agricultural region. In particular, we focus on extreme crop failure years (1994, 2002, 2006) and analyze the impact of upwind droughts on heat and moisture imports into the region. Our results indicate that low-yield years are often associated with stable high-pressure systems that lead to a decreased import of moisture from the surrounding oceans. Within the breadbasket, however, this caused higher-than-usual surface sensible heating. Moreover, the analyzed low-yield years coincide with widespread droughts over the Australian continent. We find that upwind droughts can further influence moisture and heat imports to the region. During the initial phase of the Millennium Drought in 2002, crop failure over the breadbasket exceeded 50% and only around 9% of the precipitation over the region originated from (upwind) land — this constitutes a decrease of 5.0% compared to the climatological average. Simultaneously, the heat import from remote land regions increased from an average of 22.8% to 24.7% in 2002. While our findings suggest that upwind droughts played only a minor role for Australia's largest breadbasket due to the influence of oceanic contributions in the region, other agricultural areas that show a larger dependency on moisture and heat imports from the land would be more susceptible to upwind climate anomalies. 
The oldest Nama Group exposed: Insights from the Tsaus Mountains(Tsau Khaeb National Park)
Authors: Uahengo Collen-Issia , Bowyer Fred
Published: February 2023

The oldest Nama Group exposed: Insights from the Tsaus Mountains
(Tsau Khaeb National Park)
C.-I. Uahengo*1, F.T.Bowyer2, K.Kaputuaza1, J.Ndeunyema1, M.Yilales2, R.Alexander2, A.Curtis2, R.Wood2
1Department of Geosciences, University of Namibia, Namibia.
iuahengo@yahoo.com
2School of GeoSciences, University of Edinburgh, UK.
 
     The late Ediacaran Nama Group of southern Namibia and northwest South Africa preserves a richly fossiliferous mixed carbonate-siliclcastic shallow marine succession, subdivided into the Kuibis and overlying Schwarzrand subgroups. Whilst the termination of Schwarzrand Subgroup deposition (ca. 538 million years ago, Ma) is temporally well-constrained by numerous dated volcanic ash interbeds, the age of the base of the Kuibis Subgroup (>547.36 Ma) remains uncertain. Carbonates of the lower Kuibis Subgroup record recovery from a negative carbonate carbon isotope (δ13Ccarb) excursion (Basal Nama Excursion, BANE) that has long been thought to represent the regional expression of the Shuram δ13Ccarb excursion, which itself has recently been re-dated on multiple cratons to ~575–565 Ma. However, siliciclastic rocks of the Kuibis Subgroup preserve soft-bodied fossils of the Nama assemblage, but lack fossils diagnostic of the preceding White Sea assemblage which, along with inferred depositional rates, is commonly used to inform an age for the base of the Nama Group of ~551–550 Ma. The apparent decline in global soft-bodied fossil diversity between the White Sea and Nama assemblages has been suggested by some to reflect an extinction event that may therefore be recorded within the lowermost Kuibis Subgroup, approximately coincident with the BANE. Carbonate rocks of the Kuibis Subgroup also host the first appearances of the biomineralising Cloudina and Namacalathus, but the precise stratigraphic position of their first appearances relative to the soft-bodied fossil record and regional δ13Ccarb profile remain poorly constrained.
     Here we present new stratigraphic, palaeontological, and geochemical (δ13Ccarb and δ18Ocarb) information from the oldest strata of the Kuibis Subgroup. These new insights were gathered during a recent expedition to the westernmost exposures of the Nama Group that outcrop in the Tsaus Mountains, within the Tsau Khaeb National Park (formerly Sperrgebiet). We present the first detailed tectonic and lithostratigraphic assessment of the Tsaus Mountains, including a revised regional geological map, in addition to a high resolution δ13Ccarb chemostratigraphic profile. We use these data to provide a holistic litho- and chemostratigraphic correlation framework for the Kuibis Subgroup of the southern (Witputs) Sub-basin. All published palaeontological information, in addition to important new soft-bodied and skeletal fossil occurrences from the Tsaus Mountains succession, are correlated within this framework and discussed.
Estimating groundwater response time in humid climate by using spectral analysis
Authors: Di Dato Mariaines , Houben Timo , Attinger Sabine
Published: February 2023

During dry periods, river flow comprises baseflow, which typically generates from shallow aquifers. Understanding how such aquifers respond to climate events is key to managing environmental issues related to water supply or water quality. A typical indicator of groundwater response to climate events is the characteristic response time, which indicates the rate of depletion of shallow aquifers.The traditional method to infer the characteristic response time analyzes the slope of the hydrograph recession curve. Such a method does not account for stormwater contribution in recession analysis, thereby assuming that the catchment is dry and the only contribution to discharge originates from groundwater. As a consequence, the recession analysis might underestimate the groundwater response time, owing to the presence of faster discharge components, i.e. surface runoff or interflow, in the falling limbs.In this work, we propose an alternative methodology to calculate the characteristic response time, which is determined by analyzing the behavior of the baseflow time series in the frequency domain. The aquifer can be conceptualized as a low-pass filter, which smooths the high-fluctuating components in the recharge signal. Such behavior causes a cut-off frequency in the baseflow spectrum, which corresponds to the aquifer characteristic time. We applied this approach to several gauging stations in Germany, whose humid climate is ideal to compare the results with the classical recession analysis.We observed that spectral analysis yields characteristic response times systematically larger than the ones calculated with recession analysis. On average there is a factor of two between the estimates provided by the two methods. Overall our study emphasizes careful consideration of the estimation of groundwater response times, especially in humid and sub-humid river basins.
Multi-source assessment of uncertainty over the tropical ocean
Authors: Pradhan Rajani Kumar , Markonis Yannis
Published: February 2023

The tropical ocean, which receives a substantial volume of precipitation and evapotranspiration, has a greater impact on Earth's energy and water balance. Yet, considerable studies have been focused on the Earth's terrestrial precipitation, whereas very little attention has been given to the oceanic region. Despite the advancement of satellite and reanalysis precipitation estimates, relatively few studies explored these estimates over the oceans. In this context, we quantitatively evaluate and inter-compare the state-of-the-art satellite, reanalysis, and merged precipitation products over the tropical oceans. We use a suite of various gridded and well-known precipitation datasets such as the Integrated Multisatellite Retrieval for Global Precipitation Measurement (IMERG), Global satellite Mapping of Precipitation (GSMaP), European Centre for Medium-Range Weather Forecast (ECMWF) Reanalysis v5 (ERA5), and Multi-Source Weighted-Ensemble Precipitation (MSWEP) products to comprehensively estimate the tropical oceanic precipitation and its spatial and temporal variation. In particular, we are looking into the estimates of the total mean precipitation and its inter-annual variation. In addition, the discrepancies among various precipitation estimates are analysed as a function of different spatial and temporal scale to assess their uncertainty over tropical ocean for the first time. This study will provide deep insights into the precipitation characteristic and its spatio-temporal variability across the tropical ocean. Moreover, such information will help to revisit the estimation of the global water budget components in the near future.
Variation in ecosystem carbon allocation patterns among different vegetation types in Western Ghats, India
Authors: Kothandaraman Subashree , Dar Javid , Sundarapandian Somaiah , Khan Mohammed
Published: February 2023

A major global challenge is the urgent need to bend the curve of rising atmospheric carbon dioxide (CO2) concentration. Carbon (C) pools in forests play an important role in regulating the regional and global C cycles. In this study, C stocks of all the pools {live biomass (trees and non-tree vegetation), detritus (deadwood and forest floor litter), and soil} were assessed from six vegetation types {3 natural forests (tropical dry deciduous, semi-evergreen and evergreen) and 3 plantations (teak, rubber and areca nut)} in Kanyakumari Wildlife Sanctuary, Western Ghats, India. The total ecosystem C stock averaged 262.7 ± 56 Mg C ha-1 and ranged between 94.7 and 506.8 56 Mg C ha-1. Soil was the major C pool in tropical dry deciduous forest and areca nut plantation, whereas biomass was the largest pool in other vegetation types. The C stocks of teak and rubber plantations were comparable with those of dry deciduous and semi-evergreen forest types respectively. The C stocks were significantly positively correlated with stand density, basal area and mean annual precipitation, and negatively correlated with mean annual temperature. The present study would improve our understanding on C allocation patterns at ecosystem-level in different vegetation types of Western Ghats, and can be used for ecosystem restoration and forest management programmes to enhance C sequestration.
Agroclimatic relationships in Central Scandinavia, c. 1560–192
Authors: Skoglund Martin
Published: February 2023

For the region of central Scandinavia, there exists high-quality tree-ring based temperature reconstructions that cover the last 1200 years. This paper utilizes climate reconstructions in tandem with historical sources to estimate the relationships between climatic variability and agriculture in central Scandinavia between the 16th and 20th centuries, with a specific focus on temperatures, harvests and agricultural dates. Using historical sources on agriculture importantly allows for evaluation of different climate reconstructions before the era of instrumental measurements. Thus, this paper not only sheds light on the societal relevance of past and present climatic change and variability, but also provides insights into the climate of the past.While historical harvest dates in many parts of Europe have been employed to reconstruct growing season temperatures, this paper also includes virtually unique long time-series of sowing and hay-cutting dates going back to the late 17th and 18th century, respectively, and shows how these type of agricultural dates also had significant relationships with temperature variability in central Scandinavia. Furthermore, agriculture in this region, located in the northern boreal zone, was heavily constrained by growing season temperatures, and harvests exhibits much clearer relationships with climatic variability compared with less marginal regions of Europe. Climate-harvest relationships are studied at a local level, allowing for spatial anlaysis of micro-climatological differences within the larger regional context.
Vulnerability of Firn to Hydrofracture, Part II: Greenland’s Ice Slab Regions
Authors: Culberg Riley , Meng Yue , Lai Ching-Yao
Published: February 2023

Hydrofracture and rapid lake drainage can transport surface meltwater to the bed of the Greenland Ice Sheet, thereby coupling surface mass balance processes and dynamic mass loss. Vertical hydrofracture is widely assumed to occur in the ablation zone, where abundant surface runoff that can fill fractures. However, in Greenland, the runoff line has expanded into the accumulation zone due to the development of ice slabs in the firn. It remains unclear whether surface runoff from these ice slab regions also drains locally to the bed. Recent observations in Northwest Greenland suggest that when meltwater penetrates ice slabs via surface fractures, it leaks off into a relict firn layer and does not initiate unstable vertical hydrofracture that propagates throughout the ice thickness. At the same time, buried supraglacial lakes have been observed to drain to the ice sheet bed this same region. Therefore, to assess the mass balance impact of ice slab expansion, it is important to understand if and when surface-to-bed hydrofracture may occur in these regions.In “Vulnerability of Firn to Hydrofracture, Part I: Poromechanical Modeling”, we developed an analytic expression for the maximum tensile effective stress within the firn layer beneath a water-filled fracture in an ice slab. Here we apply this model to Greenland’s ice slab regions. We use an ensemble of in situ and remote sensing observations to constrain the physical, mechanical, and hydraulic parameters in our model. We then run a Monte Carlo analysis to constrain the physically-plausible range of maximum tensile effective stress in the firn for two scenarios: a water-filled crevasse in an ice slab or a supraglacial lake over a fractured ice slab. Our results show that the maximum stress in the firn layer is always less than in an equivalent solid ice column, and typically remains compressive, because the imposed load is partially accommodated by a change in pore pressure. An overlying lake further stabilizes the system by increasing the lithostatic stress that acts to close the fracture. Therefore, in Greenland, the relict firn layer can be an important stabilizing factor that suppresses surface-to-bed hydrofracture under ice slabs, despite the abundance of both surface crevassing and meltwater.