bluuebunny/crossref_metadata_2025 huggingface dataset:
Deciphering the changes associated with Western Disturbances impacting “Karakoram Anomaly”
Authors: Javed Aaquib , Kumar Pankaj
Published: March 2022

In contrast to the general retreat of glaciers across the globe, the glaciers of the Karakoram (KR) region of Karakoram-Himalayas (KH) have displayed an anomalous divergent response, with some glaciers remaining either stable or surging. This phenomenon is known as the "Karakoram Anomaly." Although many factors are reported to have control over it, the present study tries to decipher the role of Western Disturbances (WDs) in establishing and sustaining the anomaly. These upper-tropospheric extra-tropical cyclones impact the region during the boreal winter. WDs are the major contributor of winter snowfall over KR, dictating the mass-balance variability of the region, as reported by previous studies. Therefore, to achieve the study's objectives, a tracking algorithm is applied to 39-seasons (1980-2019; Nov-Mar) of the ERA5 reanalysis dataset. Initial simulations suggest that the tracking algorithm has the potential to capture nearly ~90% of the reported tracks accurately in terms of their time of occurrence. Furthermore, the associated statistics generated for tracks passing through KR revealed a ~10% increase in the WD-associated precipitation intensity. The results shall be further analyzed to quantify the contribution of WD-associated snowfall in modulating the regional mass-balance anomaly. Additionally, the various mechanisms involved in WDs' formation and intensification will also be investigated.
Variability of the relationships between heatwave and dust intrusions over France
Authors: Mandija Florian , Lukaj Edmond , Frasheri Neki , Vila Floran
Published: March 2022

The western region of Europe is frequently affected by the mineral dust intrusions from the nearby desert outbreaks. There are many investigations of dust events, especially over its southern part. However, in the contest of climate changing, a profound analysis of the evolution and dynamics of these episodes over the France region is of the great interest.

Satellite remote sensing techniques are utilized to investigate the whole region. The Moderate Resolution Imaging Spectroradiometer (MODIS) and the Multi-angle Imaging Spectroradiometer (MISR) data are used to obtain the optical and microphysical aerosol properties. Also, the numerical models such are Regional Climate Model (RegCM4-Chem) and Weather Research and Forecasting (WRF) have been used in this study. Moreover, the air quality model Prev'air is used to provide the air quality maps, especially over the main urban and industrial regions. Aerosol Robotic Network (AERONET) stations based on this region will provide data to validate the low spatial resolution results.

Beside of the aerosol events analysis, weather patterns, like temperature (surface and 850 hPa) Sea Level Pressure and 500 hPa Geopotential heights are derived from reanalysis during the periods of dust events.

More specifically, the main objectives of this study were:

Characterization of episodes of extreme dust aerosol load, using long-term observations.

Characterization of extreme temperature episodes, using meteorological data.

Establish links between dust and heat wave episodes, as well as their associated synoptic patterns.

The novelty of this work is the synergetic use of aerosol and meteorological data to establish the common mechanisms of two types of hazards which are detrimental to human’s health but have traditionally been studied separately: dust intrusions and heatwaves.  

The results show not regular trends on the dust intrusion frequency, duration, and intensity over the entire region. However, the combination of the meteorological and aerosol data over the different sectors of this region, give some insights over the features of these events. Furthermore, a heatwave catalogue with the extreme temperature events is associated with high aerosol loads in this region is created.
Iron deposit effect observed in Kiruna geomagnetic fluctuations: Indications for an improved approach of magnetotellurics searching methods
Authors: Longeon Bastien , Yamauchi Masatoshi
Published: March 2022

Geomagnetic data at Kiruna station (KIR) in Sweden has been expected to be affected by the iron ore mine because high conductance underground generally means depressed ΔZor dZ/dt compared to ΔH or dH/dt, where Z and H are downward and horizontal components, respectively, Δ indicates deviation, and we took 1-min average of 1-sec resolution data when defining d/dt values. We examined the 1-sec resolution magnetometer data using both frequency-domain (i.e., standard magnetotellurics) and time-domain analyses, and compared general behaviours with the other high-latitude stations on the same longitude (Hornsund: HRN, Abisko: ABK, Lycksele: LYC, Uppsala: UPS, Nurmijärvi: NUR) for the same period (September 2014-2020).

Surprisingly, we found KIR anomaly only in time-domain derivative dB/dt and not in the frequency domain spectrum. To quantify this anomaly, we examined the standard deviation of each parameter (1-min average of 1-sec resolution values) over 3 hours. With this quantification, the level of anomaly was about the same between old magnetometer until 2019 and new magnetometer from 2020. The anomaly is somewhat present in both dZ/dt and dH/dt but is the clearest in the ratio of dZ/dt to dH/dt.  On the other hand, neither ΔZ nor ΔH showed anomaly. Furthermore, no anomaly is recognized in the inclination I (=atan(Z/H)), i.e., ΔI nor dI/dt. From all of these, we believe that the observed anomaly is caused by underground iron ore deposit and not by the magnetometer filtering setting. The reason why the anomaly is found only in d/dt values is not clear, but we suspect that the iron ore deposit might cause time delay between dZ/dt and dH/dt when step-like variation dominates as the input variation, which is often the case with auroral activity. In such variation, neither the frequency domain analyses, nor simple time domain analyses (ΔB) show any anomaly.

We applied this method to the other meridians (three meridians in North America). We could not find any anomaly similar to what KIR data showed. However, we found another type of anomaly (on dI/dt) in Barrow, Alaska. It can be related to its location, surrounded by the arctic sea in both east and west, but we have not yet found an appropriate interpretation.

[Acknowledgements:  This work resulted from a 2021 summer internship study at the Swedish Institute of Space Physics, Kiruna.   The 1-sec resolution geomagnetic data are obtained from INTERMAGNET and are originally provided by SGU (Sweden: UPS, LYC, KIR, ABK), FMI (Finland: NUR), PAS (Poland: BEL, HLP, HRN), GSC (Canada: BLC, CBB, FCC, IQA, OTT, RES, STJ, YKC), USGS (USA: BRW, CMO, FRD, SHU, SIT), IPGP (France: CLF), ZAMF (Austria, WIC), and ASCR (Czech: BDV).]
Aerosol and cloud properties over a coastal area from aircraft observations in Zhejiang, China
Authors: Che Yunfei , Zhang Jing , Zhao Chuanfeng , Zhou Xu , Duan Jing
Published: March 2022

Using in-situ aircraft observations from six flights over Zhejiang on Sep. 1 and Sep. 4, 2016, this study investigates differences in aerosol and cloud properties between daytime and nighttime. The samples were divided into marine type and continental type based on the backward air mass trajectories and aerosol characteristics. The results show that the aerosol number concentration (Na) near the ground during daytime is higher than that at nighttime. During daytime, Na has a significant decreasing trend near the top of the planetary boundary layer (PBL), which is not obvious during nighttime. There may be still a relative high concentration of aerosols remaining in the transition zone between the PBL and the free troposphere. Under similar liquid water content (LWC) conditions, the cloud droplet number concentration (Nc) at night is lower, and the cloud droplet effective diameter (cloud ED) is larger. The total Na of marine type aerosols is generally lower than that of continental type aerosols, but for aerosols with particle diameters greater than 1 μm, the marine type aerosols are higher. The study shows a strong negative Na-cloud ED relationship for marine type aerosols, but no obvious Na-cloud ED relationship for continental type aerosols. The number of cloud condensation nuclei (CCN) is higher under high-Na conditions; the ratio of CCN to Na reveals that the activation efficiency of marine type aerosols is higher than that of continental type aerosols. There is no obvious difference in activation efficiency between day and night.
Micro-SWIFT SPRAY modeling of atmospheric dispersion around a nuclear power plant site with complex topography
Authors: Dong Xinwen , Zhuang Shuhan , Fang Sheng
Published: March 2022

The nuclear emergency response for accidental release around the nuclear power plant site (NPPs) requires a fast and accurate estimate of the influence caused by gaseous hazardous pollutants spreading, which is critical for and preventing protecting lives, creatures, and the environment. However, as usual, the NPPs is consist of dense buildings and multi-type terrain, e.g. river and mountain, which poses challenges to atmospheric dispersion calculation for response tasks. Micro-SWIFT SPRAY (MSS) comprises both the diagnostic wind model and the dispersion model, which enables the airflows and atmospheric dispersion simulation with the meteorological and other inputs. For a small-scale scenario, especially, the separate module for obstacles influence modeling provides the potential capability of precise atmospheric dispersion. But the error behavior of such a scenario around a nuclear power plant site with complex topography remains to be further demonstrated. In this study, MSS is comprehensively evaluated against a wind tunnel experiment with a 1:600 scale for the small-scale (3 km × 3km) atmospheric dispersion modeling. Tens of buildings located in this scenario of a NPPs surrounded by a mountain and river. The evaluations for diagnostic wind modeling include the speed, direction, and distribution of horizontal airflows and vertical profile of speed at a representative site. And for the concentration calculation, horizontal distribution, axis profile, and vertical profile at a representative site. The results demonstrate the MSS can reproduce fine airflows near the buildings but overestimate the wind speed. The maximum deviation of vertical speed is around 2.09 m/s at the representative site. The simulated plume of concentration reproduces the highest concentration place and matches the observations well. The axis profile of concentration is underestimated and the vertical profile displays an increasing deviation with the height increase. Compared with the observations, the FAC5 and FAC2 of concentration simulation reach 0.945 and 0.891 in the entire calculation domain, which convinces the performance of MSS in small-scale modeling.
Virtual geological road in Cheremosh river valley, Outer Ukrainian Carpathians
Authors: Oliinyk Mariia , Bubniak Ihor , Bubniak Andrij , Bihun Mykola
Published: March 2022

Field research is an integral part of the educational process in the Earth sciences. Сovid-19 restricted our movement on the territory of Ukraine. Our team decided to create virtual geological objects. We present the results of creating a virtual route along the Cheremosh River.

The results of this road will be used for one of the educational courses at the Institute of Geodesy. In the summer, we organized several field trips to create virtual geological objects. The digital models created by us will become the main source of information for students. During the pandemic, we did not have the opportunity to make trips for groups of students and we forsee it. Thanks to the visualization of the outcrops, we skip the field stage for students and we emphasize the cameral stage in our course. In the first lecture we will tell about the idea and history of our creation of this course, give examples of programs and show the processing of data collected by us.

The geological outcrops we study are located in the Skyba and Boryslav-Pokuttia nappes of the Outer Ukrainian Carpathians. The stratigraphic section is represented by a flysch complex ranging in age from Cretaceous to Neogene. The second important complex is the lower molasses of the Neogene age. In outcrops we observe a number of structures that are important for structural geology, sedimentology and others.

To create our objects, we used two methods – terrestrial laser scanning (TLS) and digital photogrammetry (SfM). Both of these methods allow to gather collection of geological data on outcrops rapidly and these data have usually high quality. Information about the structure of outcrops is presented in the form of a cloud of points that allows you to build three-dimensional models of outcrops (DOM).

         
Macroplastics monitoring in the Sea Scheldt estuary 
Authors: Velimirovic Milica , Teunkens Bert , Ghorbanfekr Hossein , Buelens Bart , Van Damme Stefan , Tirez Kristof , Vanhaecke Frank
Published: March 2022

The presence of small plastic fragments in open ocean water was first noticed in the 1970’s. Throughout the last decade, the scientific interest has been renewed and has pointed out that rivers may act as sinks for land-based plastic pollution and a potential major source of marine plastic debris, thus presenting an environmental threat. As a long-term consequence, plastic fragmentation will lead to pollution release that can impose a negative impact on river, as well as marine ecosystems, especially once they enter the food webs. As a result, this is a topic of increasing concern, but research on this issue is still in its early stages with fundamental gaps in the understanding of the sources, transformation pathways, fragmentation processes, fate of the land-based plastic pollution and estimates of the riverine plastic flux in general.

In order to identify the most polluting rivers and to prioritize mitigation efforts, accurate estimates of global riverine plastic emissions are required. The present work is aimed to give an overview of the morphology, size and composition of plastic debris found in the Sea Scheldt estuary (Belgium). For that purpose, in 2018, 3 sampling campaigns were performed by using an anchor netting technique with the mesh size of the nets progressively becoming smaller, reaching 5 mm at the tip of the nets. The samples originating from the Scheldt were separated into two categories based on their appearance (morphology) and size. The morphology consisted of 5 classes: fragments, foam, foil, filaments and pellets, whilst the size was divided into 6 categories: 0-2.5 cm (where 0 represents smallest size of the mesh being 5 mm); 2.5-5 cm; 5-10 cm; 10-20 cm; 20-30 cm; and larger than 30 cm. As a result, a grand total of 12,801 plastic items were collected. On average 1.6x10-3 items per m3 were found as suspended fraction of plastic debris in the Scheldt river. Foils were the most abundant with more than 88% of the samples being characterized as such, followed by fragments for 11% of the samples and filaments constituting less than 1% of the plastic debris. By using FTIR, polypropylene and polyethylene were identified as the most common polymers found with an abundance of more than 70%. This can be expected, as polypropylene and polyethylene make up for more than 50% of the plastic production in general. Finally, analysis of plastic debris by using μ-XRF spectrometry presents a good method for the identification of the mineral elements present. Ca, P, S and Si are the most abundant elements in the plastic debris, followed by Al, Fe and Ti.

M.V. is a senior postdoctoral fellow of the Research Foundation – Flanders (FWO 12ZD120N).
Role of spatial resolution in simulating hydrological processes using a physically-based hydrological model
Authors: Reghunath Gowri , Mujumdar Pradeep
Published: March 2022

The hydrological responses of a catchment are predominantly governed by complex interactions among processes occurring at various spatial and temporal scales. Hydrological modelling serves as a powerful tool in assimilating this complex behaviour of hydrological systems. As hydrological processes exhibit non-linear behaviour at all scales, it becomes essential to understand how much spatial approximations are necessary for a model to adequately represent reality. This study aims at investigating the influence of spatial resolution of a physically-based hydrological model in capturing the hydrological processes of a catchment which is characterized by large scale variability in the regional distribution of water resources. In this study, the grid-based Variable Infiltration Capacity (VIC) model is employed at spatial resolutions of 0.125, 0.25, and 1-degree latitude by longitude over the Cauvery river basin in peninsular India. The model incorporates both surface and subsurface hydrological processes, features sub-grid land surface and vegetation heterogeneity, facilitates the inclusion of multiple soil layers with variable infiltration, and computes non-linear baseflow. The model is calibrated with respect to observed streamflow at various gauge stations located across the basin. The water balance components such as surface runoff, evapotranspiration, soil moisture at three distinct soil layers, and baseflow are estimated for the period 1951-2016. Performance evaluation of outputs obtained from model simulations adopting different spatial resolutions is carried out at seasonal and annual time scales. As the spatial scale increases, the catchment tends to organize and attenuate the complex behaviour of processes. This study provides significant insights towards adopting effective modelling strategies to ensure the adequate representation of hydrological processes in regionally complex catchments.
Investigating the associated dynamics of 2019 Heat wave over India
Authors: Devi Rani , Gouda Krushna Chandra
Published: March 2022

India witnessed the second longest recorded heat wave during May-June 2019 causing more human deaths with the maximum temperature recorded was about 51.8oC in a place called Churu in the state of Rajasthan. The present study investigated the spatio-temporal pattern of the maximum temperature and the associate heat waves in the country. The relationship of the heat wave spread and the variables like temperature, humidity, soil moisture as well as the land use and land cover is explored. The dynamics of large scale oceanic and atmospheric features resulting advection and local heating mechanism is found to be the reason of such high intense heat wave in 2019 summer season. The anomaly of all the related weather parameters are linked with the intense maximum temperature and resultant heat wave and the hot spots are identified. The impacts of ENSO (including 'El Niño Modoki') and MJO on the longest and highest heat wave phenomena are also quantified for the year 2019. The role of soil moisture and the evapotranspiration also observed in the analysis which clearly shows lack of these parameters also triggers the intense heat wave events. This study will help in better understanding of the local heat wave dynamics and these informations can be useful for the public health interventions against the intense heat wave situations.

 
Explaining reported drought impacts in the European Alpine region with selected drought indices
Authors: Stephan Ruth , Dormann Carsten F. , Stahl Kerstin
Published: March 2022

Even across Europe’s generally water-rich Alpine region the number of reports on negative drought impacts increased recently. The Alpine Drought Impact report Inventory EDIIALPS archives information of more than 3,200 specifically reported impacts with a majority in the last decade underlining the need for region-specific drought monitoring and adaptation strategies. The relation between drought conditions and drought impact occurrence has not been analyzed systematically in this heterogeneous mountain terrain. This study aims to improve such systematic understanding through the analysis of selected drought characteristics and reported impacts. Therefore, we assigned EDIIALPS’ reported impacts as soil-moisture drought impacts (SMD) and hydrological drought impacts (HD) and explored statistically the relation of these two impact groups to the following drought indices: Soil Moisture Anomalies, Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, Vegetation Condition Index and Vegetation Health Index. The density of the reported SMD impacts and HD impacts increased clearly, the stronger the index’ value indicates drought conditions - apart from the vegetation indices. However, the correlation tests between reported impacts and indices did not identify explicit linear relations. To capture non-linear effects and differences between reported SMD impacts and HD impacts we applied decision trees using recursive partitioning. This way, we identified the Standardized Precipitation and Evapotranspiration Index to be most important for reported HD impacts and the Soil Moisture Anomalies to be most important for reported SMD impacts. To predict impact occurrence we recommend to model and evaluate a combination of drought indices allowing non-linearities in order to improve drought impact monitoring and early warning.
Ice-flow history and observations from the ice base of Jutulstraumen drainage basin (Antarctica)
Authors: Franke Steven , Neckel Niklas , Gerber Tamara Annina , Eisermann Hannes , Asseng Jölund , Steinhage Daniel , Helm Veit , Eisen Olaf , Drews Reinhard , Eagles Graeme , Miller Heinrich , Dahl-Jensen Dorthe , Jansen Daniela
Published: March 2022

Future sea-level predictions require that the history of the Antarctic Ice Sheet is well understood and constrained by observations. Much of the ice sheets’  ice-dynamic properties are governed by processes at the ice-bed interface which can be imaged with radar sounding surveys. Here we use a combination of ultra-wideband radio-echo sounding data, satellite radar and laser altimetry data, as well as electromagnetic waveform modeling to characterize the properties of the ice base and the evolution of the subglacial morphology of the Jutulstraumen drainage basin (western Dronning Maud Land, Antarctica). Based on the classification of the bed topography, we reconstruct the step-by-step modifications the subglacial landscape has experienced since the beginning of the glaciation of Antarctica, 34 million years ago. Between 2017 and 2020, we find evidence of active episodic cascade-like subglacial water transport along the subglacial valley network. In addition, our high-resolution radio-echo sounding data reveal a cluster of anomalous basal ice units whose material properties we constrain by electromagnetic waveform modeling. Through this, we aim to derive the physical conditions at the ice base, and establish a link to the subglacial hydrology system. The combination of these observations will represent an important step towards a better understanding of large-scale ice-sheet dynamics in western Dronning Maud Land.
Timing of Glacier Retreat on Mt. Davraz by Cosmogenic Chlorine-36 in the Western Turkey
Authors: Altinay Onur , Sarıkaya Mehmet Akif , Çiner Attila , Yıldırım Cengiz , Žebre Manja , Stepišnik Uroš
Published: March 2022

The Taurus Mountain Range extends parallel to the Mediterranean coast of Turkey. It hosts lofty mountains (>3000 m above sea level, a.s.l.) carved by glaciers in the Late Pleistocene. Despite the recent studies in Anatolia, Mt. Davraz (2635 m a.s.l.) has not been studied in detail and its glacial chronology was lacking. This study presents our first findings of the glacial history, origin and geochronology of Mt. Davraz, which is located SW of Eğirdir Lake (915 m a.s.l.), 100 km north of Antalya city. Tectonics, karstification, glaciation, and periglaciation have led a distinctive geomorphology of the area. The main landscape of the area is predominantly shaped by paleoglaciers. Cirques are the dominant glacial erosional landforms, and most of them were developed on the northern slopes of Mt. Davraz. Based on the topographical limitations, cirque paleoglaciers could not to transformed into valley glaciers. Although it is one of the lowest mountains in the Taurus Mountain Range, it has a large hummocky field with an area of about 3 km2 on the northern slope. It was developed by a paleo-ice cap. There is also a smaller hummocky field deformed by a rock glacier advancements on the E-NE slopes of the mountain. In order to understand the timing of paleoglaciations, we obtained 6 cosmogenic 36Cl surface exposure ages from the moraine boulders on hummocky field. Based on the preliminary results, Mt. Davraz hummocky field yielded sequential retreat history; the eastern hummocky field deposited their moraines at 21.7 ± 1.5 ka ago, while the western hummocky field at 17.7 ± 1.2 ka ago. Our results show that the glaciers started to retreat by the Last Glacial Maximum (LGM) and continued to the earlier stages of Late-glacial. This work was supported by TÜBİTAK-118Y052 project.
The Regional Impact of Wet and Windy Extremes Over Europe, Following North American Cold Spells
Authors: Leeding Richard , Messori Gabriele , Riboldi Jacopo
Published: March 2022

Due to the compounding nature of co-occurring weather extremes, these events can be highly detrimental to economies, damaging to infrastructure and result in loss of life. Previous work has established a connection between cold spells over North America and extreme wet and windy weather over Europe. This work attempts to identify a statistical link between the regional impact of wet and windy extremes over Europe based on the regional impact of cold spells over North America. We identify cold spells for 41 overlapping regions over North America for full winter (DJF) seasons between 1979 and 2020 using ERA5 data, employing 4 methodologies for the computation of onset dates. The impact of extreme precipitation and wind events over 6 regions of western and central Europe is analysed. Consistent across all methodologies, cold spells over eastern and mid USA are followed by significant wind extremes over Iberia, whilst cold spells over eastern Canada are followed by significant wind extremes over northern Europe and the British Isles. The regional impact of precipitation extremes shows much greater variance, though we find significant Iberian and southern European precipitation for cold spells over eastern USA, consistent with that found for wind extremes. The majority of extreme precipitation and some significant wind extremes also precede the peak of the cold spell. We show also that the frequency of extreme precipitation and wind events over Iberia increases by 1.5 to more than 2 times the climatological frequency, following cold spells in most North American regions.
Spatial and vertical patterns of Soil Organic Matter and Carbon content in the salt marshes of the Venice Lagoon (Italy)
Authors: Puppin Alice , Tognin Davide , Ghinassi Massimiliano , Franceschinis Erica , Realdon Nicola , Marani Marco , D'Alpaos Andrea
Published: March 2022

Salt marshes are intertidal ecosystems characterized by mostly herbaceous halophytic vegetation and shaped by complex feedbacks between hydrodynamic, morphological, and biological processes. These crucial yet endangered environments are among the most carbon‐rich ecosystems on Earth and support a diverse range of ecosystem services, including coastal protection and biodiversity increase. Their primary production coupled with rapid surface accretion results in the ability to sequester and store atmospheric carbon at high rates. Accumulation of organic matter in salt marshes has also a structural role, as it contribute to vertical accretion necessary for marshes to keep up with relative sea-level rise. A better understanding of the processes regulating soil organic matter (SOM) dynamics in tidal environments is a critical step to predict salt-marsh evolution in the face of climate change and anthropogenic disturbances and to further elucidate carbon sink potential of salt marshes, to the benefit of management and conservation strategies. Toward this goal, we analysed organic matter content in salt-marsh soils of the Venice Lagoon (Italy) from 48 sediment cores to the depth of 1 m, collected along 8 transects in different salt marshes. Soil samples were taken at 12 depths from each core and subsamples were prepared for different analyses, including soil density, organic matter content and grain size distribution. Percent organic matter was evaluated using Loss On Ignition and was used to estimate carbon stock and accumulation rate. Organic matter content in salt marshes showed a large variability, with important implications on marsh resilience and on the related ecosystem services. We observed a vertical decrease of organic matter with depth, but also the presence of organic-rich layers below the surface, as stratigraphy retains the signature of past depositional history. Furthermore, observed landward increase of organic content emphasizes the crucial role of fluvial inputs. Dry bulk density showed a clear relationship with percent organic matter, providing additional insights to evaluate contributions of organic and inorganic matter to surface accretion in salt marshes. Preliminary results offer insights on spatial and vertical patterns of SOM in salt-marsh soils and highlight the often overlooked carbon sink potential of salt marshes, showing carbon stock and accumulation rate values comparable to those attributed to forest environments. Differences between measured values along transects and at different study sites suggest that SOM accumulation primarily varies depending on organic source and conservation conditions, mostly affected by vegetation, physical and hydromorphological factors, which are in fact interrelated.
Precipitation Extremes over central India - Past, Present, and Future: Regional Earth System Model Perspective
Authors: Kumari Amita , Kumar Pankaj
Published: March 2022

In the warming climatic scenario, Indian Summer Monsoon (ISM) rainfall and its extremes, especially on the local scale, is expected to alter that profoundly impact the societal, environmental, and economic well-being of the million people residing in central India. Therefore, understanding ISM mean and extreme rainfall for the past, current, and reliable projection are crucial for effective adaptation strategies, remains a major scientific challenge. The Regional Earth System Model (ROM) driven by MPI-ESM-LR over the CORDEX-South Asia framework under the RCP8.5 scenario at a finer horizontal resolution of 0.22° was used to investigate the future of mean and extreme precipitation over central India. The ROM’s performance is demonstrated with respect to observed precipitation data from India Meteorological Department. ROM shows its skill in capturing the mean and extreme precipitation (PEs) during the ISM along with its intraseasonal variability.  Further, an effort is made to investigate the projected changes in precipitation extremes (PEs) during the mid-future (MF; 2040-2069) and far-future (FF; 2070-2099) concerning the historical period (1969-2000) under the RCP8.5 scenario. The results highlight, two-fold rise in the frequency of PEs is likely to be expected by the end of the century. In addition to this, the study also projects the intraseasonal variability, i.e., the active and break spells that crop up during the peak monsoon months (July and August). The active spells were found to be more persistent in the projected period. The changes in the different precipitation events are subjected to strong cyclonic circulation, reduced vertical wind shear, and enhanced moisture transport.
Hygroscopicity of organic aerosols linked to formation mechanisms 
Authors: Liu Jieyao , Zhang Fang , Xu Weiqi , Sun Yele , Chen Lu , Li Shangze , Ren Jingye , Hu Bo , Wu Hao , Zhang Renyi
Published: March 2022

Organic aerosols (OAs) account for a large fraction of tropospheric fine particulate matter, but the hygroscopicity of OA is poorly understood. Here we show remarkably-enhanced water uptake capacity of OA due to formation of highly-oxidized oxygenated OA on new particle formation (NPF) events in Beijing. While non-nucleation processes also produce oxidized OA, their hygroscopicity exhibits little enhancement. As a result, a correlation between the hygroscopicity and oxidation state is absent for OA on non-NPF days. Further analysis reveals that the highly-oxidized oxygenated OA is 2.5 and 5-fold as hygroscopic as the oxidized primary OA and less-oxidized oxygenated OA, respectively. Our results suggest that nucleation-initiated photooxidation of volatile organic compounds to produce water-soluble organic acids may dominate on NPF days, and the aqueous oligomerization to yield less water-soluble products might occur on non-NPF days.
Temporal and spatial variability of precipitation extremes across India
Authors: Mandraha Shivanand , Ray Sujata
Published: March 2022

The occurrence of extreme precipitation events is a matter of concern for any nation because a slight change to it can have a devastating effect on the socio-economic condition for the state. To assess the temporal and spatial variability of precipitation extremes, extreme rainfall data over India (except Island part) have analyzed using quantile perturbation method. The data used in the study is taken from the Climate Research Unit, University of East Anglia (UK). It is a gridded data of 0.5o × 0.5o resolution. The analysis showed that different part of the studied area had varying perturbations in the precipitation extremes. The study found a significant anomaly in precipitation extreme for all the periods but the 1910s, 1920s, 1930s, 1940s, 1990s, and 2000s decades had covered wide area as compared to the remaining periods with reference to the long period of 1901-2017. In the 1910s, the positive anomaly was found near most of North East India, while negative anomaly was found in central and north India. In 1930-1940s, the central part had a positive anomaly, and the north part had a negative anomaly. Negative perturbation is present in the most of east region (the Gangetic plain) in 1990-2000s. A positive anomaly found on the west side. But in the recent decade very few anomaly present in the whole region. To partially address the reason behind the perturbation correlation analysis has been done between extreme precipitation anomaly and Indian Ocean Dipole. The result shows most of the part of East, North East side of India are having moderately negative correlation while some of the South and North India are having moderately positive correlation. The sea surface temperature over the Indian Ocean might be the main driver for the decadal perturbations in precipitation extremes.
Sodium/halides aqueous droplets in vacuo at the sub micron scale : size, temperature and concentration effects on their structural properties from simulations at the microscopic level.
Authors: Masella Michel , Vallet Vaérie , Réal Florent , Houriez Céline
Published: March 2022

We investigated sodium/halides (F, Cl, Br and I) aqueous droplets in vacuo at the microscopic level from molecular dynamics simulations at the 100 ns scale performed using a sophisticated polarizable all atom force field whose parameters are assigned only from high end quantum ab initio computations [1]. Long range electrostatic and polarizable forces are computed according to a Fast Multipole Method scheme devoted to polarizable force fields based on the induced dipole moment approach [2]. For Cl, Br and I we simulated 10k water droplets corresponding to 0.2, 0.6, 2.0 and 4.6 M salt concentrations and on a range of temperatures included between 260 and 320K. For F, we simulated 10k droplets corresponding to 0.2, 0.6, 0.8 and 1M salt concentrations. We also simulated a reduced set of salty droplets at 300K (in particular corresponding to NaCl salts) at the 100k (up to 100 ns) and at the 1M water molecules scale (up to 30 ns) [3]. We present here a detailed analysis of the structural properties of these droplets regarding ion spatial distributions, ion aggregates (size, composition, morphology, lifetime and distribution), water ordering (relative to pure water droplets) and droplet surface potentials. In the particular case of NaCl droplets, we also discuss droplet curvature effects on the latter properties from data corresponding to 10k, 100k and 1M systems.

[1] Trumm et al, Modeling the Hydration of Mono-Atomic Anions From the Gas Phase to the Bulk Phase: The Case of the Halide Ions F-, Cl-, and Br-, J. Chem. Phys., 136 (2012) 044509.; Réal F et al,  Revisiting a Many-Body Model for Water Based on a Single Polarizable Site. From Gas Phase Clusters to Liquid and Air/Liquid Water Systems, J. Chem. Phys. 139 (2013) 114502.; Réal F et al, Structural, Dynamical, and Transport Properties of the Hydrated Halides: How Do At- and I- Bulk Properties Compare with those of the other Halides, from F- to I-, J. Chem. Phys., 144 (2016) 124513
Quantification of model uncertainty in the projection of sub-daily maximum wet spell length under RCP 8.5 climate change scenario 
Authors: Majhi Archana , Dhanya Chandrika Thulaseedharan , Chakma Sumedha
Published: March 2022

Global precipitation characteristics have been significantly altered due to the global warming. While, this is well-known, the sub-daily extreme precipitation events are more sensitive, as compared to the daily-scale. The future intensification of these sub-daily extremes worsen the risk of floods and droughts, thereby posing threat to the natural ecosystem and human society. The ability of general circulation models (GCMs) in simulating the sub-daily precipitation may be inferior, due to their coarser resolutions and complex parametrization schemes. In addition, the characteristics such as the intensity, frequency and duration of sub-daily precipitation may not be correctly simulated by the GCMs. Despite this fact, there are limited studies to investigate the credibility of sub-daily precipitation projections by GCMs, and the related uncertainty. Therefore, in order to investigate the reliability of GCMs in the projections of such extremes, we have used 20 Coupled Model Intercomparison Project phase 5 (CMIP5) models under RCP8.5 (Representative Concentration Pathway). The uncertainty is estimated in the projections of maximum wet spell length (WSL) i.e. maximum number of consecutive wet hours in four different meteorological seasons (DJF, MAM, JJA, and SON), for both near (2026-45) and far future (2081-99) time periods. The equatorial regions of Africa and South East Asia, showed higher model disagreement during every season. In contrast the equatorial regions of South America and South Asia showed significantly more disagreement during DJF and JJA season. Model uncertainty in each hemisphere is observed to be higher during their respective wet seasons. Though the model uncertainty in far future is varying when compared with that in near future, the uncertainty is not increasing globally. Also, the uncertainty is observed to have significantly decreased during MAM season in far future. The spatial contribution towards higher model uncertainty range, is less as compared to lower uncertainty range over the globe. While the magnitude of model uncertainty is varying with time, the latitudinal heterogeneity remains same in both the time period. 

Keywords: precipitation extremes, sub-daily, wet spell, GCM, projections, uncertainty, RCP 8.5

 
Mapping single hazards and multi-hazard interrelationships in Global South urban areas: A case study in Kathmandu, Nepal.
Authors: Thompson Harriet , Malamud Bruce D. , Gill Joel C. , Šakić Trogrlić Robert
Published: March 2022

Achieving a holistic approach to disaster risk reduction in urban areas remains challenging. This requires understanding the breadth of single hazards and multi-hazard interrelationships across various spatial and temporal scales that might impact a given urban area. Here we describe an approach to systematically map the single hazards and multi-hazard interrelationships that have a potential to impact Kathmandu, Nepal, one of the focus cities of the UK Global Challenges Research Fund (GCRF) Tomorrow’s Cities research hub. Using an existing classification of 21 natural hazard types (across six hazard groups: geophysical, hydrological, atmospheric, biological, space), we first searched for evidence of each of these occurring in or affecting Kathmandu. We used systematic mapping to find and select evidence, applying a simple Boolean search with keywords and reviewing publications across all years available on online databases before selecting evidence from 2010 onwards where available. The spatial boundary around Kathmandu was not specified, rather we chose evidence based on recorded or potential impacts in the city. When searches returned many results (i.e., over 100), we skimmed titles and abstracts for spatial and temporal occurrence to select up to 5 sources. We examined and integrated evidence from diverse sources, including academic literature, grey literature, traditional media (e.g., English language Nepali newspapers), global and national disaster databases and social media. This evidence was then used to assess potential multi-hazard interrelationships that may occur in Kathmandu. Using this blended evidence, we found 21 single hazard types that might impact Kathmandu. We found case study evidence for 11 interrelationship types that have had previous impact in Kathmandu with many more that are theoretically possible. The results illustrate the complexity of the hazard landscape, with many single hazards and multi-hazard interrelationships potentially impacting Kathmandu. This knowledge can inform the development of dynamic risk scenarios, to use in planning and civil protection, thus strengthening multi-hazard approaches to disaster risk reduction in Kathmandu.
The role of teleconnections in complex climate network
Authors: Saha Ruby
Published: March 2022

A complex network provides a robust framework to statistically investigate the topology of local and long-range connections, i.e., teleconnections in climate dynamics. The Climate network is constructed from meteorological data set using the linear Pearson correlation coefficient to measure similarity between two regions. Long-range teleconnections connect remote geographical sites and are crucial for climate networks. In this study, we discuss that during El Ni\~no Southern Oscillation onset, the teleconnections pattern changes according to the episode's strength. The long-range teleconnections are significant and responsible for the episodes' extremum ONI attained gradually after onset. We quantify the betweenness centrality measurement and note that the teleconnection distribution pattern and the betweenness measurements fit well.
Improving the performance of Aquifer Storage and Recovery schemes using Multiple Partially Penetrating Wells
Authors: Tiwari Shubham , Yadav Brijesh Kumar
Published: March 2022

Aquifer Storage and Recovery (ASR) is one of the most effective ways of artificial groundwater recharge to assure freshwater availability during droughts in arid and semi-arid areas. However, this method of managed aquifer recharge is less prevalent in saline groundwater regions due to low recovery efficiency (RE). The injected freshwater of an ASR scheme in saline regions is decreased due to mixing between fresh-saline water and the upward movement of stored freshwater due to gravity effects. The losses due to mixing, however, can be reduced by managing the operational parameters. This study proposes a solution for reducing losses of injected freshwater due to gravitational within the saline aquifer by introducing multiple partially penetrating well-system (MPPW) in place of a single fully penetrating well-system (SFPW). A variable-density flow (SEAWAT) model is used to simulate and compare the ASR system performance for specific hydrogeological conditions and variable operational parameters for SFPW and MPPW well systems. The results indicate that by using MPPW in place of the SFPW ASR well system, 8 to 15% extra injected freshwater can be recovered. The difference in recovery efficiency due to the use of MPPW in place of SFPW tends to increase with the increasing values of injected freshwater storage duration and the number of successive ASR cycles and decreases with increasing the injection/recovery rates and injection volumes. This research provides the basis for understanding the suitable ASR well type for any specific site for different operational factors.
Periodicities in fair weather potential gradient at ground level from different latitudes 
Authors: Tacza José , Nicoll Keri , Macotela Edith
Published: March 2022

Analysis of the variation of the potential gradient (PG) at ground level is important to monitor the global electric circuit and the different solar and geophysical phenomena affecting it. However, this is challenging since several factors (e.g., meteorological) produce perturbations in the potential gradient. For this reason, timeseries and spectral analysis of PG at several stations are required. In this work, for the first time we performe the spectral analysis of the potential gradient recorded at several sites located at Vostok, Concordia, Halley and Casleo (South Hemisphere), and Sodankyla and Reading (North Hemisphere). In order to find the main periodicities and how the amplitude of those periods change as a function of time we use the Lomb-Scargle Periodogram and the Wavelet Transform, respectively. For all PG sites the periodicities of 0.5, 1, ~180 and 365-day were found. It was also found evidence of the ~27- and ~45-day periods. Further analysis using the cross-wavelet transform for PG versus cosmic rays, PG versus Madden-Julian Oscillation index, and PG versus meteorological parameters, shows that the 27- and 45-day periods are likely related to the solar rotation and Madden- Julian Oscillation, respectively. Moreover, for the 27-day period we found that the relationship is stronger during the occurrences of co-rotating interaction regions.
Measles Masked By Covid-19: A Literature Review
Authors: Moodley Dirusha , Goren Katherine
Published: March 2022

Measles is one of the world’s most infectious communicable diseases. Although almost entirely preventable by vaccine, there have been recent case surges, with almost 9.8 million cases reported globally in 2019, the highest seen since 1996. This spike in measles cases, can be attributed to several factors including vaccine hesitancy, low vaccine confidence, international travel, and poor access to vaccines. While measles cases appear to be declining across the globe since the beginning of the COVID-19 pandemic, a catastrophic measles resurgence following the pandemic is likely. With the increased public health demands related to the COVID-19 pandemic, healthcare resources have been prioritized differently, resulting in disruptions in measles case surveillance, investigation, and vaccination efforts. This shift has resulted in many measles vaccination campaigns being postponed, resulting in a large measles immunity gap in some of the world’s most vulnerable populations. With first dose measles coverage rates stagnating at 85% and likely dropping with the recent halt of many vaccination campaigns, strategic measles vaccination interventions are urgently needed.
CRISPR: On the road to restoring sight to the blind
Authors: Basilious Amy
Published: March 2022

CRISPR-Cas9 is a novel gene-editing tool that promised to revolutionize our ability to treat genetic conditions when first introduced. Today, it continues to fuel many areas of health research, ranging from cancers to sickle cell disease to Huntington’s disease.1–3 Vision science researchers immediately saw the potential of CRISPR, with some of the earliest experiments exploring CRISPR as a treatment option for inherited ocular disorders.4 Only a few years later, in March 2020, vision research was again at the forefront of this field.5 A CRISPR therapy was injected into the human body for the first time in an attempt to correct a vision threatening mutation.5 Inherited retinal diseases have traditionally presented therapeutic challenges, but CRISPR is now providing hope for a cure.