bluuebunny/crossref_metadata_2025 huggingface dataset:
Nature-based Solutions, mangrove restoration and global coastal flood risk reductions
Authors: Tiggeloven Timothy , Mortensen Eric , Worthington Thomas , de Moel Hans , Spalding Mark , Ward Philip
Published: March 2022

In order to mitigate the expected increase in coastal flood risk it is critical to better understand how adaptation measures can reduce that risk, including Nature-based Solutions. We present the first global scale assessment of the (future) flood risk reduction and the benefits mangrove restoration. Unlike previous studies on Nature-based Solutions, we provide a quantitative assessment of mangrove restoration and nature contributions to people in terms of monetary flood risk reduction, people exposed to flooding, and poverty indicators. We find that mangrove restoration is an effective measure to contribute to future flood risk reduction and estimate that a large share of future flood risk may be reduced by implementing mangrove restoration. Our estimates indicate that nature-based solutions like mangrove restoration constitute promising complementary measures to other adaptation measures (e.g. structural measures). We further indicate that the benefits of mangrove restoration are unevenly distributed across the population in terms of poverty, and show that only looking into property damages and people exposed is not enough to understand the range of impacts of adaptation on population distributions. Even though this study can only be used as a first proxy analysis or indicative, it provides valuable insight into the feasibility of mangrove restoration at the global scale, and supports the need for sustainable adaptation and global assessmenst of Nature-based Solutions. Furthermore, implementing adaptation measures, such as mangrove restoration, in developing countries will contribute to the resilience of people in poverty, poverty alleviation and help tackle poverty traps.
Investigating the response of seismic anisotropy in the crust to the 2014–15 Bárðarbunga-Holuhraun dyke intrusion and eruption
Authors: Bacon Conor , Baltas Elisavet , Johnson Jessica , White Robert , Rawlinson Nicholas
Published: March 2022

Existing evidence points towards the evolution of magmatic intrusions being a complex function of both existing structures and the stress state within the crust. Consequently, developing means to make in-situ measurements and effective models of these two factors would provide crucial insight into the dynamics of volcanic systems, feeding forward to volcanic monitoring and crisis response agencies. Seismic anisotropy—the directional dependence of seismic wavespeeds—has been shown to be a direct proxy for the in-situ stress state of the crust, as well as the existing fabric, but its potential for further developing our general understanding of magmatic intrusions has yet to be realised. The wealth of geophysical data recorded during eruptions in the last decade presents a unique opportunity to explore these important natural phenomena in exceptional detail.

We first establish a general model for the bulk properties and structure of upper crust in the central highlands of Iceland by analysing shear-wave splitting (SWS), a common and near-unambiguous indicator of seismic anisotropy. Using this model as a starting point, we subsequently explore the evolution of seismic anisotropy before, during, and after the 2014–15 Bárðarbunga-Holuhraun dyke intrusion and eruption. Seismicity associated with this magmatic intrusion was used to capture the spatial evolution through time of this event in unprecedented detail. Persistent seismicity at “knot points” along the path of the dyke intrusion allow us to negate the effect of changes to source-receiver path on the measured variations in seismic anisotropic properties.

Our preliminary work suggests the far-field response of seismic anisotropy to the intrusion can be explained by existing models relating the stress field to the orientation of the fast direction. It is apparent, however, that this simple model fails to explain sufficiently our observations in the near field. Whether this is due to shortfalls in the stress modelling, the influence of the presence of melt along the raypath, or potentially a breakdown in the established relationship between stress and seismic anisotropy remains unclear.
Comparative analysis of wind and solar energy potential from differnet  climate regions, case studies  of Morocco , India and  Kenya 
Authors: Mendyl Abderrahmane , Gandhi Arun , Musyimi Peter K , Székely Balázs , Weidinger Tamás
Published: March 2022

Wind and solar energy have emerged as the one of the most popular and successful sources of renewable energy in combating environmental degradation and climate change. Countries around the world are developing policy mechanisms for increasing the share of renewable energy technologies for fulfilling their energy demands. Both wind and solar have proved their potential as clean and efficient sources of energy generation. Therefore, transitioning into a sustainable future requires a shift from fossil fuels to renewable energy technologies. The main goal of this study is to compare wind and solar energy potential for different climate regions of Morocco, India and Kenya using standard methodologies.

In this study we have used the wind profile power law relationship for estimating the wind speed and power at 100 m level. We are analysing long term synoptic datasets from 2 to 4 synop stations in arid and humid regions of North India, Morocco and Kenya based on the Meteomanz standard meteorological database. Stability dependent power law profile approximations were used and comparisons made with ERA5 reanalysis data. Estimation of wind energy production for different continental wind generators were also provided. Using the connection between the wind speed and profile law we demonstrated how wind energy can vary using different values of power law exponents for different climatic regions.

Standard meteorological measurements (temperature, humidity and cloudiness) gave the opportunity for estimation of global irradiance which was also compared with the ERA5 dataset. Applicability of widely used direct and diffuse irradiance parameterizations for different climate regions were also investigated.

For instance, in Marrakech the six Pasquill-Gifford stability classes were determined by estimating the global solar irradiance for cloudy and clear sky conditions as well as the wind speed. Analysis of the data showed that windspeed at 10 m varied between 1.8 m/s in the early morning (UTC 06:00) to 3.5 m/s in the evening (UTC 18:00) while the windspeed at 100 m varied between 2.6 m/s and 5 m/s at the same time periods.  The estimated wind energy at 100 m level for rural areas was more than that of urban areas The wind energy at 100 m varied between 47.2 KW in the early morning (UTC 06:00) to 573 KW in the evening (UTC 18:00) for the rural areas while in urban areas the variation was between 83.8 KW to 670.5 KW during the same time periods. The annual average global solar radiation was found to be maximum during the afternoon with a value more than 970 W/m2.
Pantanal’s 2020 fire season in perspective: the case of a natural heritage reserve
Authors: Silva Patrícia S. , Nogueira Joana , Libonati Renata
Published: March 2022

Pantanal saw a catastrophic fire season in 2020, with a quarter of the biome hit by flames (around 4 million ha). Protected and indigenous areas burnt entirely, and it is estimated that at least 17 million vertebrates died, including several endangered species endemic to the biome. These dramatic events drew attention to the occurrence and aftermath of fire within a fire-sensitive ecosystem such as Pantanal’s wetlands.

The RPPN (Reserva Particular do Patrimônio Natural) SESC Pantanal was one of such protected areas severely affected in 2020, with around 2/3 of its territory burnt. Here, we analyse the historical fire behaviour within the RPPN, including the 2020 events, using remote sensing products over the 2001-2020 period. 

Although fire has historically occurred within the RPPN at an average of 2 400 ha burned per year, the 2020 fire events were an absolute outlier with more than 70 600 ha burned. Before 2020, only 2010 reached above 10 000 ha of burned areas, and the most extreme events were found to be those above 3 000 ha. When considering the 2001-2019 period, wetlands and grasslands are the land cover types that burn the most (52 and 17% of the total burned area, respectively), followed by forests and savanna formations (16 and 9%, respectively). The year of 2020, however, changed this pattern: most burned areas occurred in forested areas (40%), followed by grasslands (26%) and savanna formations (24%). We also found that fire is not recurrent: during the 19 years of historical data the vast majority of burned areas occurred only once (60%), 35% burned up twice or thrice, and solely 5% burned more than 3 times.

Future climate change assessments seem to point at a warmer and drier future for the biome, when events such as 2020 might become more regular. Our results provide an historical characterization leading up to the 2020 fires within the RPPN SESC Pantanal, that may be of use for fire managers in light of future climate change. 
Ice Sheet Decline and Rising Atmospheric CO2 Control AMOC Sensitivity to Deglacial Meltwater Discharge
Authors: Sun Yuchen , Knorr Gregor , Zhang Xu , Tarasov Lev , Barker Stephen , Lohmann Gerrit
Published: March 2022

The last deglaciation was characterized by a sequence of abrupt climate events thought to be linked to rapid changes in Atlantic meridional overturning circulation (AMOC). The sequence includes a weakening of the AMOC after the Last Glacial Maximum (LGM) during Heinrich Stadial 1 (HS1), which ends with an abrupt AMOC amplification at the transition to the Boelling/Alleroed (B/A). This transition occurs despite persistent deglacial meltwater fluxes that counteract vigorous North Atlantic deep-water formation. Using the Earth system model COSMOS with a range of deglacial boundary conditions and reconstructed deglacial meltwater fluxes, we show that deglacial CO2 rise and ice sheet decline modulate the sensitivity of the AMOC to these fluxes. While declining ice sheets increase the sensitivity, increasing atmospheric CO2 levels tend to counteract this effect. Therefore, the occurrence of a weaker HS1 AMOC and an abrupt AMOC increase in the presence of meltwater, might be explained by these effects, as well as in combination with changes in the magnitude or routing of meltwater discharge.
Effect of organic loading rate on biogas production and concentration of heavy metals and valuable elements in continuous anaerobic co-digestion of manure and reed canary grass
Authors: Zaffar Nazia , Ferchau Erik , Heilmeier Hermann , Wiche Oliver
Published: March 2022

Anaerobic digestion technique and production of bioenergy from biogas is an important contribution to achieving the targets of climate protection. Concomitantly, the use of digestates as secondary raw material for the production of fertilizers and the extraction of economic valuable elements are increasingly considered. The latter requires profound knowledge on the element concentrations in digestates and how changes in process parameters affect their enrichment. In this study a lab scale continuous anaerobic digestion with different organic loading rates (ORL) were performed to explore effects of loading rate on biogas production and concentration of heavy metals (Zn, Cr, Ni) and valuable elements (Ge, REEs) in digestate. The pH was 6.8–7.2 throughout the whole process. In a 30 liter reactor with working volume of 25 liter grass (Phalaris arundinaceae) and manure (20/80, 30/70, 40/60, 50/50, 60/40 ) were added as a substrate at different OLR (1, 2, 2.5, 3, 3.5, 4 kg VS m-3 d-1). The digestate of each organic loading rate was analyzed by ICP-MS. Increasing the OLR significantly increased gas production by 64%, 12%, 8%, 16% and 20%, respectively. While biogas production increased, concentration of heavy metals (Zn, Cr, Ni) and valuable elements (Ge, REEs) decreased at each level of OLR increase except between OLR 2 and OLR 3.  The increased biogas production was most likely caused by higher amounts of readily degradable organics in the fermenter, while decreasing concentrations of elements in digestates result from a dilution of initially high element concentrations in the manure with low concentrated grass biomass. In fact, we could say that the concentrations of elements in manure were by far higher compared to the grass. However, there was OLR 3 where higher inputs of biomass did not negatively affect element concentrations in digestate. Surprisingly at this OLR highest relative increase in gas production was observed. This suggests that at this loading rate enrichment of elements through losses of carbon and dilution with increasing contents of low concentrated biomass was balanced. We could demonstrate that OLR fundamentally impacts gas production and mineral element concentrations in digestate. The effects depend initially on element concentrations in biomass and gas production which potentially offers novel perspectives for optimization of biogas process towards a phytomining of valuable elements and use of digestates as secondary raw materials.
Sensitivity to Microphysics and PBL Schemes for Extreme Precipitation over the Black Sea Region in Future Climate: Warm and Cold Cases
Authors: Kelebek Mehmet Baris , Önol Barış
Published: March 2022

Detailed information about extreme precipitation is crucial due to the impacts on the human environment. Recently, high-resolution regional climate models (RCMs) are run at convection-permitting scales to investigate the regional precipitation extremes. The Black Sea region is one of the intriguing regions for modelling studies because of its distinctive topographical features where orographic forcing and strong air-sea interactions intensify destructive heavy precipitation. Recently, RCMs have been tested in order to find the most suitable configuration to represent precipitation over this region. Although the historical simulations are beneficial to test the model performance, model configurations may exhibit different spatiotemporal characteristics in simulating extreme precipitation due to the shift of the seasons in a possible warmer future. Recent studies focusing on the intensification of extreme precipitation events highlighted the model sensitivity to increasing sea surface temperature (SST) over the Black Sea. Therefore, future simulations focusing on different model configurations may provide valuable information to understand the response of RCMs in a changing climate. In this study, we downscaled the last generation CMIP6 MPI-ESM1.2-HR outputs by using the WRF model at 3 km horizontal resolution to test the model’s sensitivity for different microphysical and planetary boundary layer (PBL) parameterization options under the SSP5-8.5 future socioeconomic global change scenario. We selected cold and warm extreme precipitation cases and performed 3-days convection-permitting simulations over the complex topography of the Black Sea region. For the cold case, simple single-moment schemes produced less precipitation compared to more complex schemes, especially over the mountains, because of the insufficient representation of snowfall. For the warm case, the difference between the simulations is similar to the cold case but, the magnitude is lower. The change of the PBL scheme affects the vertical and horizontal distribution of microphysical properties and precipitation distribution near the coasts and the mountains.
High resolution acoustic imaging of frontal dynamics and thermohaline finestructure in the Southwest Atlantic sector of the Southern Ocean
Authors: Ehmen Tobias , Sheen Katy , Watson Andrew , Brearley Alexander , Palmer Matthew , Roper Daniel
Published: March 2022

The Southwest Atlantic section of the Southern Ocean is a highly energetic confluence zone where Pacific and Antarctic waters flow via the Antarctic Circumpolar Current (ACC) to merge with waters from the Atlantic Ocean and contribute to the global overturning circulation. However, there is an insufficient understanding of sub-mesoscale variability in the region. Such processes are known to play an important role in the vertical and lateral exchange of water masses, along with tracers such as carbon, atmosphere-ocean exchange, ocean productivity, and the mixing budget necessary to complete the overturning circulation. In particular, observations of the subsurface structure of frontal systems on high spatial scales are currently lacking, with typical hydrographic transects being too coarse to resolve sub-mesoscale processes and ACC filaments.

Here we present the first multichannel seismic images of ocean finestructure to the north of the North Scotia Ridge in the Southern Ocean, which cross several frontal systems and bathymetric features. High-resolution (O(10m)) sections of sub-surface thermohaline structure are revealed and analysed by combining the acoustic information with hydrographic (CTD, XBT and ARGO floats), current velocity (VMADCP) and satellite altimetry data. In addition, diapycnal mixing and potential vorticity estimates are generated from acoustic data. The sections reveal an intricate and complex pattern of oceanic finestructure: very high thermohaline gradients are present in shallow and intermediate waters of up to 700 m depth associated with Subantarctic Surface Water, Subantarctic Mode water and a mix of Antarctic Intermediate Water and Antarctic Surface Water; curving features, lenses and filaments with length scales of 100m-10km are found at the Polar Front and Southern ACC front; and steep continuous gradients with separate filaments are typically present in deeper sections (up to 2000 m) associated with Circumpolar Deep Water. Furthermore, acoustic reflections provide evidence that bathymetric features like the Maurice Ewing Bank or the Northeast Georgia Rise disrupt the flow of intermediate and deep water in the region and enhance diapycnal mixing.
Time-lapse Volumetric Seismic Imaging of Water Masses at a Major Oceanic Front
Authors: Chen Xiaoqing , White Nicky , Woods Andy , Gunn Kathryn
Published: March 2022

Oceanic fronts play a key role in modulating water mass transfer. Nevertheless, detailed information about frontal structure on appropriate temporal and spatial scales is difficult to obtain. Here, we investigate the structure of a dynamic frontal system associated with intense mesoscale eddy activity at the Brazil-Falkland Confluence of the South Atlantic Ocean using a time-lapse volumetric seismic reflection (i.e. acoustic) survey. This survey was processed by adapting standard signal processing techniques. A sequence of eleven calibrated time-lapse vertical sections from this survey reveals the detailed evolution of a major front. It is manifest as a discrete planar surface that dips at less than two degrees and it is traceable to a depth of almost 2 km. The shape and surface outcrop of this front are consistent with sloping isopycnal surfaces of the calculated potential density field and with coeval sea surface temperature measurements, respectively. Within the upper 1 km, where cold fresh water subducts beneath warm salty water, a number of tilted lenses are banked up against the sharply imaged front. The biggest lens has a maximum diameter of about 35 km and a maximum height of about 800 m. It is cored by cold fresh water which is associated with an acoustic velocity anomaly. Time-lapse imagery suggests that it grew and decayed within eleven days. On the southwestern side of the advecting front, large numbers of deforming lenses and filaments with length scales of 50 to 100 km are swept toward the advecting front. Spatial patterns of diapycnal mixing rate estimated from vertical displacements of tracked reflective horizons show that the front and associated structures condition turbulent mixing in significant ways. Finally, cross-correlation techniques are used to track the dynamic movement of frontal structures on timescales of minutes to days. This unprecedented imagery has profound implications for a fluid dynamical understanding of water mass modification at frontal systems.
Unexpected movements of earthworms between tree rows and crop alleys in a Mediterranean agroforestry site
Authors: D'Hervilly Camille , Bertrand Isabelle , Berlioz Laurent , Dufour Lydie , Marsden Claire
Published: March 2022

In alley cropping sites, parallel tree rows covered with herbaceous vegetation are added into cropped fields. These tree rows provide an additional habitat for many soil organisms in plots that are usually low in biodiversity. Previous studies showed that tree rows present a higher diversity and higher densities of soil fauna compared to the crop alleys. However, it is not sure that the crop alleys really benefit from the presence of additional fauna in the tree rows. A possible benefit could come from a dispersal of soil fauna hosted in the tree rows towards the crop alleys during favorable periods of time, but such movements have never been investigated. Our experiment investigated the movement of earthworms in tree rows vicinity in a Mediterranean alley cropping field planted with walnut trees, in which crop alleys were ploughed and cultivated with pea. Traps, consisting of three joined plastic walls sunk vertically into the soil and delimiting a cubic 25*25 cm wide soil block of 15 cm depth were placed at 30 cm from the tree row border in March 2019. These traps were opened on one side, allowing soil fauna entrance either from the tree row or from the crop alley, and defaunated at trap implementation (5 replications). Traps were removed 2 months after the beginning of the experiment and earthworm density determined by manual sorting. In addition, the plot was sampled at different distances from the tree row (0 m, 0.3 m, 1 m and 6 m i.e. in the middle of the crop alley) for earthworm density determination in 25*25*30 cm soil blocks at trap implementation and removal. Results showed that the distribution of epigeic earthworms (living at the soil surface) vary with the distance from the tree row, with more individuals found in the tree row and in its immediate vicinity than in the middle of the crop alley, while endogeic earthworms (living in the soil) presented no significant variation in their distribution with the distance from the tree row. Traps were mostly recolonized by endogeic earthworms, and significantly more earthworms were found in traps opened towards the crop alley than in traps opened towards the tree row. These results suggest than Spring was not a favorable season for earthworm dispersal from the tree row in this site, and that earthworms more probably used the tree row and its vicinity as a refuge against adverse conditions in the crop alley. This type of experiment should be repeated at other seasons, and with varying management practices of the crop alley, as different conditions could induce different movements.
Aerosol levels over Southeastern Brazil retrieved by Remote Sensing and simulated by WRF-Chem Transport Model
Authors: rojas noelia , Liduvino Angel , rojas Joel , de Fatima Andrade Maria , Akemi Marcia
Published: March 2022

In this work, we combine Aerosol Optical Depth (AOD) products derived from MODIS and AERONET instruments, and WRF-Chem simulations in order to analyze the aerosol levels over the Metropolitan Area of São Paulo (MASP), in southeastern Brazil. Five MODIS AOD products were initially considered for validation against AOD data obtained from four AERONET stations during a period of six years (2014-2019). For the analysis, a spatiotemporal window methodology was used, assuming that the aerosol plume is homogeneous within a certain time-space limit. This methodology showed that the most adequate space-time limit for the validation of the MODIS AOD data is less than 15 km, and 15 minutes before and after the overpass of the Terra and Aqua satellites. A time series and statistical analysis were necessary to find the best product that represents the aerosols on the MASP. Satellite-derived AOD products reach a good accuracy when more than 66% of retrievals fall within Expected Error (EE) envelope (withinEE > 66%). Using this approach, Dark Target of 3km spatial resolution (DT-3K) has shown good accuracy (withinEE > 86%) compared to the other satellite products. With this information, both MODIS and AERONET data were then compared with AOD fields derived from WRF-Chem simulation for June 2017. On cloudy days, aerosol products do not provide AOD data information, hence in-situ PM2.5 data from CETESB air quality stations over the MASP were analyzed to complement the WRF-Chem model performance. Analysis between simulated and in-situ PM2.5 surface concentrations showed similarities on some days. Both the model and the air quality stations reached maximum peaks in some days of June 2017, even though the model did not reach the high values as the air quality stations. Discrepancies between model results and observations at site-specific locations at both surface and total-column are related to a misrepresentation of local conditions, not only in terms of emissions but also in terms of land-use and atmospheric stability. This work represents a first effort that combines different remote sensing and modeling tools to improve understanding of how aerosol emissions impact the air quality in the MASP and surrounding urban areas. 
Mapping Groundwater-dependent Ecosystems in Arid Central Asia: Implications for Controlling Regional Land Degradation
Authors: Liu Hu , Liu Chan , Yu Yang , Zhao Wenzhi , Zhange Zhao , Guo Li , Yetemen Omer
Published: March 2022

Groundwater-dependent ecosystems (GDEs) exist all over the world, especially in water-limited regions. To achieve better water management, it is necessary to map and identify GDEs. Central Asia (CA) is one of the most arid regions in the mid-latitudes and one of the major regions with shallow groundwater tables. However, the role of groundwater in the impacts of climate change and regional anthropogenic activities on environmental risks, especially regional desertification, is inadequately understood due to the limited available research on GDEs. In the present study, a remote sensing-based method was used for mapping GDEs in regional CA, and three means—overlay analysis, correlation analysis, and the water balance method—were adopted to validate the accuracy of the mapping outcomes. Our results indicated that: 1) GDEs were concentrated around large lakes and in central Kazakhstan (between 46°N and 50°N latitudes), and areas "Very Likely" and "Likely" to be GDEs accounted for 36.89%, and 28.85% of the total natural vegetation areas, respectively; 2) at the watershed scale, the Sarysu Basin had the largest proportion (94.02% of the area) of potential GDEs while the Ysyk-Kol Basin had the lowest proportion (17.84%); 3) all the three validation methods indicated a good performance for our GDE mapping results. We concluded that the remote sensing-based GDE identification method can be considered a potential approach for mapping GDEs regionally. Better recognition of relationships among groundwater availability, ecosystem health and groundwater management policies should be developed by conducting further studies, to protect GDEs and to prevent regional land degradation. 
Effects of temperature and moisture manipulation on biological activity of Northern and Southern taiga peat soils 
Authors: Trifonova Viktoriia , Ryzhova Irina , Matyshak George , Chuvanov Stanislav , Tarkhov Matvey
Published: March 2022

Wetland ecosystems play a significant role in organic carbon conservation; one meter layer of peat soils store over 30 percent of terrestrial organic carbon (Lal, 2008). Ecosystems have different sensitivity to climate change in different nature zones (IPCC, 2014) due to various moisture and temperature regime.

The aim in this work is to define effect of temperature and moisture on mineralization rate in peat soils in Northern and Southern taiga.

The samples of Cryic Histosol (WRB, 2014) were taken from Northern Taiga (65°18'52" N, 72°52'32" E). The samples of Fibric Histosol (WRB, 2014) were taken from Southern Taiga (55°40'04" N 36°42'49" E). In laboratory conditions, samples were brought to certain soil moisture (SM): 30, 60, 80, 100 % (Gritsch, 2015), temperature of incubation was ranging from 5 to 25 ◦C (equal-time method).

In all the cases basal respiration (BR) was growing with increasing of temperature. Samples of Cryic Histosol are more sensitive to changes both in temperature and moisture. BR varies from 0.58 ±0.26 (30% SM and 5 ◦C) to 13.53±0.22 mg C-CO2/g/h (100% SM and 25 ◦C). Q10 coefficient varies from 4.64 to 2.82 respectively (this coefficient demonstrates differences in the temperature sensitivity of soil respiration (Kirschbaum, 1995)). For samples of Fibric Histosol BR varies from 0.75±0.01 (30% SM and 5 ◦C) to 6.14±0.26 mg C-CO2/g/h (100% SM and 25 ◦C). Q10 coefficient varies from 2.70 to 2.18 respectively.

Influence of moisture and temperature on biological activity in all of the cases was statistically confirmed, but interaction of factors is significant only for Cryic Histosol. According to the results, Cryic Histosol is more sensitive to temperature and moisture change, than Fibric Histosol. Peat soils in the northern area are subjected to more rapid organic carbon mineralization after a change of hydrothermal regime, than southern peat soils. In conclusion, Q10 coefficient variation indicates that soils with low soil moisture are more sensitive to temperature changes.
The decadal modulation of the ENSO-Australian monsoon rainfall teleconnection 
Authors: Heidemann Hanna , Ribbe Joachim , Cowan Tim , Henley Benjamin J.
Published: March 2022

We analyse the decadal variability in the relationship between Australian monsoon rainfall (AUMR) and the El Niño Southern Oscillation (ENSO). A composite analysis is conducted to examine monsoon season (December to March) rainfall anomalies over northern Australia during central and eastern Pacific ENSO events between 1920 to 2020. These composites are evaluated separately for positive and negative phases of the Interdecadal Pacific Oscillation (IPO) and reveal differences in AUMR anomalies with respect to ENSO event diversity. During central Pacific (CP) El Niño events, the key month is February, in which the AUMR is above average in positive IPO phases and below average during negative IPO phases. This is due to low-level circulation anomalies northwest of Australia, which are cyclonic in the positive IPO phases and anticyclonic in negative IPO phases, in addition to moisture fluxes directed towards the central Pacific, away from northern Australia. During CP La Niña events, there are insignificant rainfall anomalies over northern Australia in December during positive IPO phases. In contrast, during negative IPO phases, strong and significant positive rainfall anomalies cover much of northern and eastern Australia, which relate to large-scale convergence of moisture and an intensification of the Walker Circulation. In summary, AUMR anomalies during CP ENSO events differ between positive and negative phases of the IPO due to variability in the large-scale atmospheric circulation.
Study of heliospheric magnetic flux rope instabilities driven by distortions
Authors: Capellas Coderque Samuel , Nieves-Chinchilla Teresa
Published: March 2022

Heliospheric magnetic flux ropes (MFRs) are usually considered to be the magnetic structure that dominates the transport of mass and energy from the Sun into the heliosphere. They entrain a confined plasma within a helically organized magnetic topology, transporting magnetic flux and helicity into the heliosphere, as well as being the main driver of geomagnetic activity.

Following the methodology introduced by Florido-Llinas. et. al. (Sol. Phys. 295, 118, 2020) we carry out a further study to evaluate the effect of distortions in MFR stability in the heliosphere. This way, we gain an insight in the understanding of the dynamical processes ruling the propagation and evolution of MFRs in the interplanetary medium, in a view to improve our space weather forecasting capability.
The Grad-Shafranov reconstruction technique: overview, improvements and analysis
Authors: Jumilla Lorenz Jordi , Nieves-Chinchilla Teresa
Published: March 2022

Heliospheric magnetic flux ropes (MFRs) are usually considered to be the magnetic structures in the solar wind confining plasma in a static or dynamic equilibria. They are also associated with the internal structure of the Coronal Mass Ejections (CMEs), the main drivers of geomagnetic activity. In the Heliosphere, MFRs can be described as straight axial-symmetric geometry with a variation with radius and angle of pressure and magnetic field.

Several missions such as STEREO or Solar Orbiter provide in-situ measurements of such magnetic structures. A well-known method to analyse them is the Grad-Shafranov reconstruction technique. In this article we provide a detailed overview, review of its variations and improvements and analysis of new events using this technique. Both quantitative and qualitative classification of such MFRs is done according to its orientation, shape and magnetic field and pressure profiles.

Based on the flux rope model described by Nieves-Chinchilla et al. (2018), we also investigate the physical characteristics and the underlying basic equilibrium state.
Projection of future pluvial flood events over Himalayan river basin under CMIP6 climate data
Authors: Moothedan Antony Joh , Dhote Pankaj R. , Thakur Praveen K. , Agarwal Ankit
Published: March 2022

A hydrological model conceptualizing a certain rainfall event of a watershed is capable of reflecting the hydrological situation and assessing its response not only for historical but also projected climate data in future. This works presents a futuristic flood discharge estimation using the established event based HEC-HMS model corresponding to the meteorological forcing from shared socioeconomic pathways (SSPs) of Coupled Model Intercomparison Project-6 (CMIP6). The hydrological model was setup for flood-prone Himalayan Beas river basin, India. The calibration and validation of the model was carried out for the rainfall induced flooding events of monsoon 2005 and 2010, respectively. The coefficient of determination (R2) and Nash–Sutcliffe efficiency (NSE) were achieved to be 0.82 and 0.79 for calibration and, 0.84 and 0.80 for validation at Bhuntar station, respectively. An improved carbon simulated CMIP6 rainfall data holding of ACCESS-ESM1.5, after bias correction and downscaling, was used to simulate the flood hydrographs in the Beas basin till 2100. The peak discharges of each decade from 2021 to 2100 was estimated and analysed, for the SSP245 and SSP585 scenarios. For the climate projection scenario SSP245, the peak flood event was estimated to be in July 2068 with peak discharge of 4446.7 m3/s while a SSP585 scenario observed extreme flood event in July 2057 having a peak discharge of 4817.2 m3/s. The estimated discharge magnitudes from SSP245 and SSP585 schemes are comparable to the 562 years and 706 years return period discharges of the basin, respectively. The study also revealed that the frequency of flooding events are maximum in the endmost decade of 2091-2100, with an increasing trend towards the later decades.

Keywords: Flood, Hydrological Model, CMIP6, HEC-HMS, Himalayas, Beas river, Climate data
Incoherent Hadley cell and jet change in the Last Glacial Maximum: a parameter sweep study using a dynamic-core GCM
Authors: Kim Seo-Yeon , Son Seok-Woo
Published: March 2022

The incoherent Hadley cell (HC)-edge and jet-latitude change is found during the Last Glacial Maximum (LGM), whereas the robust coherent shifts of HC edge and eddy-driven jet latitude are evident in the present and future climate, especially in the Southern hemisphere. By performing parameter sweep experiments, here we investigate this incoherent HC–jet change in the LGM-like and global warming-like experiments with a dry dynamical core of the general circulation model where cooling or heating is imposed in tropical upper-troposphere and polar surface. The LGM-like experiments reveal that an incoherent HC–jet change, i.e., a poleward shift of the jet latitude but an equatorward shift of the HC edge, appears when the polar forcing is substantially stronger than the upper-tropospheric tropical cooling, indicating the broadened baroclinic zone. This broadened baroclinic zone is explained by the separate roles of fast and slow waves. As polar cooling is enhanced, fast waves contribute to the poleward shifted jet in the midlatitudes. However, slow waves in the subtropics do not change much in response to polar cooling due to an equatorward shifted critical latitude by the upper tropospheric cooling, resulting in the HC edge located on the equatorward side compared to the control simulation. Such an incoherent HC–jet change is also found in the global warming-like experiments, suggesting that a poleward HC shift but an equatorward jet shift may occur in the future climate with accelerated Arctic amplification.
Contrasts in volcanic risk perception among Goma population before the Nyiragongo eruption of May 2021 (East DR Congo)
Authors: Mafuko Nyandwi Blaise , Michellier Caroline , Muhashy Habiyaremye François , Kervyn François , Kervyn Matthieu
Published: March 2022

Risk perception is an essential element to consider for effective risk management at time of eruption, especially in densely populated cities close to volcanoes. The city of Goma in the East of the DR Congo is one these cities highly exposed to volcanic hazards and highly populated. The perception of volcanic risk involves the processes of collecting, selecting and interpreting signals about uncertain impacts of volcanic hazards. Using a questionnaire survey, this study describes the spatial variation and factors influencing the individual volcanic risk perception of 2204 adults from height representative neighbourhoods of the city of Goma before the May 2021 Nyiragongo eruption. A composite risk perception indicator was built from the perceived likelihood of occurrence of volcanic hazards and of their impacts and from the perceived likelihood of being personally impacted. Statistical analysis of survey’s results shows that the risk perception is mostly shaped by risk cognitive and psychological factors rather than demographic factors (group, family status and previous risk experience). Perceived personal exposure to and predictive power of environmental cues (sights and sounds that are considered to indicate a hazard onset) positively shape risk perception. The higher the level of personal understanding and interest in seeking  risk information, the higher the risk perception. In addition, risk perception leads to high level of anxiety. Finally, the spatial analysis shows that the highest level of risk perception was observed in the eastern part of the city, previously impacted by lava flows in 2002.  
Microbial degradation of Atrazine in Groundwater
Authors: Arar Mohammad , Bernstein Anat
Published: March 2022

Atrazine is one of the most frequently detected pesticides in groundwater. Its microbial degradation is often studied in soils, but less frequently studied in groundwater . In Israel, atrazine is the most frequently detected pesticide in groundwater. It was hypothesized that its degradation potential in groundwater is wide. Thus, this study aimed to gain indication for ongoing degradation in atrazine affected groundwater.

 Results of microcosm experiments with groundwater bacteria indicated on its degradation potential. PCR analysis of microcosms cultures has shown the presence of atzA and trzN genes. Furthermore, LC-MS analysis of groundwater extracts identified a large proportion of atrazine degradation products indicating on ongoing degradation in the field. Further isotope analysis of atrazine in  groundwater extracts will provide an additional line of evidence for ongoing degradation in groundwater.
The Kalkkop Impact Crater, South Africa, an environmental archive for MIS 7 and beyond
Authors: Kirsten Kelly , Haberzettl Torsten , Edwards Tara , Mavuso Silindokuhle , Murungi May , Mpangala Loyce , Pickering Robyn
Published: March 2022

The Kalkkop meteorite impact crater, situated within the semi-arid Nama-Karroo biome, has long been the subject of investigation. Palaeolake deposits were confirmed after three cores were drilled in the 1990s describing the fine-grained, laminated limestone stratigraphy interspersed with an abundance of fossil material. Investigations based on these cores, suggested that during the period of deposition the region experienced alternating wetter and drier climates. However, the environmental reconstruction was based on a limited number of samples over the length of the core (~90 m) and very sparse chronology. Additionally, the core was severely disintegrated due to poor handling and storage post-retrieval. New cores were drilled at Kalkkop crater in early 2019 and are curated in a custom-built cold storage facility at the University of Cape Town. Here we present data from the longer of the two cores, an 89 m long core from the centre of the crater with close to 80% core recovery. Surface palaeolake samples have been dated to the beginning of MIS 7 (~250 ka) using U–Th series, suggesting the lake deposits may cover, at least in part, the glacial termination III, a period rarely documented for southern Africa. Here, we provide preliminary results from the top 20 m based on sediment colour characteristics, XRF, ICP, biogenic silica and CNS analyses. Future research will focus on a more detailed U-Th chronology, annual layer counting and the generation of a detailed age model. The implications of this new palaeoclimate archive presented here, plus its future age model, are significant given the sites close proximity to the rich archaeological record of early modern human behaviour on the adjacent southern Cape coast.
Hydroacoustic observations of a seismic cluster at Melville Fracture Zone along the Southwest Indian Ridge in 2016-17
Authors: Ingale Vaibhav Vijay , Bazin Sara , Royer Jean-Yves
Published: March 2022

Seismic clusters of volcanic and tectonic events along mid-oceanic ridges are inherent to seafloor spreading. Due to the rapid attenuation of seismic waves in the solid Earth, land-based seismic networks lack the low-level seismicity associated with such clusters. However, regional studies using autonomous underwater hydrophones overcome this difficulty due to their sensitivity to low-frequency hydroacoustic waves, known as T-waves, that travel in the SOund Fixing And Ranging (SOFAR) channel over very long distances with little attenuation. Using hydroacoustic records from the temporary OHASISBIO network and permanent stations of the CTBT Organization, we have examined a seismic cluster near the Melville Fracture Zone (FZ) at 61°E along the ultraslow spreading Southwest Indian Ridge (spreading rate: 14-15 mm/yr).

Near 61°E, 259 events were reported in the International Seismological Center (ISC) catalogue between 9th June 2016 and 25th March 2017 in the region of 3 x 3 degrees in latitude and longitude around Melville Transform. Out of them, 17 events display normal faulting mechanisms parallel to the ridge axis (Global Centroid Moment Tensor (GCMT) solutions).

In the preliminary analysis, we have detected 4273 hydroacoustic events between 9th June and 11th July 2016, vs 28 events in the ISC catalogue, so with ~150-fold increase in the event detections. These events are mostly aligned parallelly to the ridge axis near its intersection with the Melville FZ. The event median uncertainties are ~4.7 km in latitude and longitude, and ~1.4 s in origin time. Their median acoustic magnitude or Source Level (SL) is 225.26 dB.

This seismic cluster includes several highly energetic and short duration (~10 s) impulsive events, located on the slopes of seamounts near the FZ at 61.2°E. These events are interpreted as thermal explosions resulting from direct magma supplies on the seafloor. Also, most of the hydroacoustic events are clustered around the same seamounts. There is no evidence for long mainshock-aftershock sequence at the onset of this seismic cluster. These observations point to a magmatic origin for this seismic cluster with an active source located near a chain of seamounts in the vicinity of Melville FZ.
Metal Leaching from Surface Dust of an Informal E-Waste Recycling area in New Delhi, India 
Authors: Kumari Hina , Yadav Sudesh
Published: March 2022

Recycling and disposal of e-waste by informal sector in developing nations raise concerns due to its environmental consequences and human health hazards. In this study, metal toxicity and leaching behaviour of 13 metals (Ag, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn).  were investigated in surface dust samples (n=20) of informal e-waste recycling area in New Delhi by using Waste Extraction Test (WET) and Toxicity Characteristic Leaching Procedure (TCLP). The WET and TCLP tests were developed by California’s Department of Toxic Substances Control (CDTSC) and the United States Environmental Protection Agency (USEPA) respectively to simulate landfill conditions for metal leaching under laboratory conditions. All metals were leached more in WET compared to TCLP. In WET test, Cd, Cr, Cu, Ni, Pb and Zn exceeded the prescribed threshold limits of CDTSC and failed the test whereas Cd and Pb exceeded the threshold limits of USEPA in TCLP. Though Cu, Ni and Zn are not regulatory metals in TCLP, but their leaching concentrations exceeded the threshold limits of CDTSC. In both the tests, Fe, Mn and Sn were also leached in considerable amounts. In WET, Sn (37.7) leached in maximum percentage followed by Cd (28.7), Zn (27.9), Pb (27.7), Co (21.1), Mn (14.8), Ni (11.4), Fe (8.5), V (7.6), Cu (7.5), Ba (3.5), Cr (2.9) and As (0.4) respectively; whereas in TCLP Co (20.7) leached maximum followed by Cd (17.1), Zn (12.8), Mn (7.1), Ni (6.7), Sn (4.9), Cu (3.1), Pb (2.2), Ba (1.1), Fe (0.4), V (0.3), Cr (0.2) and As (0.1) respectively. The WET test was found to be more aggressive in leaching of metals when compared to TCLP due to citrate ion chelation property. Leaching of metals higher than the threshold limits can cause contamination of soil, surface water and ground water in nearby areas and can affect the human health and environment. Therefore, there is needs to regulate policies and environmentally sound new technologies for e-waste recycling to safeguard the human health and environment.