bluuebunny/crossref_metadata_2025 huggingface dataset:
Drivers influencing the changes in the Composite Flood Vulnerability Index in the Lower Godavari Basin
Authors: Singh Apoorva , Dhanya Chandrika Thulaseedharan
Published: February 2023

The importance of studying the different dimensions of a flood disaster – hazard, exposure, resilience, and vulnerability has been highlighted in many studies. While concrete methodologies exist for estimating flood hazards and exposure, determining vulnerability remains a hurdle in flood risk assessment. Whereas the hazard and exposure analysis captures the susceptibility of physical assets, it fails to address the vulnerability of its inhabitants, which may be attributed to poverty, occupation, caste, ethnicity, exclusion, marginalization, and inequities in resource availability. Despite efforts in the mapping of flood-prone areas and developing various social vulnerability and flood vulnerability indices, there is limited understanding of the combined effect of physical and socio-economic factors on flood vulnerability. Thus, in this study, a composite flood vulnerability index (CFVI) is conceptualized to study the combined effect of physical and socio-economic factors on flood vulnerability, and the changes in the CFVI are analyzed in the floodplains of the Lower Godavari basin in India. The region between the Bhadrachalam and Konta, located on the banks of the Godavari River, experiences frequent fluvial flooding due to the backwater effect caused by the turbulence generated at the confluence of the Godavari and Sabari rivers. The study of flood vulnerability as a combination of hazard, exposure, and social vulnerability will help diagnose the cause of the vulnerability, and strategize flood mitigation efforts while ensuring social equity. Moreover, studying the spatial distribution and temporal changes in the composite flood vulnerability index at a regional scale can help design a combination of structural flood control and adaptive measures.
"Paleopedology of Siwalik Paleosols of Kangra Sub-Basin, NW Himalaya: Implication for Weathering and Climate change 11 Ma to 6 Ma"
Authors: Yadav Pooja , Hameed Abdul , Kumar Rohit , Srivastava Pankaj
Published: February 2023

The Himalayan Mountain range is the most prominent and active intracontinental range in the world. The outer part of this range is marked by the Himalayan foreland basin (HFB) in south that resulted due to the thrust loading and subsidence with synorogenic sedimentation from the hinterland. The lowermost part of the HFB is marked by the molassic sediments of “Siwalik” which thins out to the south. The time frame between 11Ma to 6 Ma (mid to late Miocene) is critical to understand the changes related to monsoon and vegetation as there is no detailed record or systematic study of late Cenozoic weathering and paleopedogenesis in fluvial sediments of the HFB. In the present study, we present a high-resolution paleopedological record of the paleosols along a traverse of ~ 1.8 km in the Kotla-Brail section of the Kangra sub-basin of the HFB. In the field, the paleosols are characterized by 1-2 m thick Bw, Bt, Bk, Bss, Bk horizons, rhizocretions, pedogenic carbonates (PC), and Fe/Mn mottles and concretions. The paleosols in the Lower Siwaliks show a dominance of 2.5 Y and 5 YR hue, whereas in the Middle Siwaliks they are defined by 5 YR and 7.5 YR hue. Micromorphology of these paleosols confirmed varying degrees of weathering, and paleopedogenesis showing a blocky structure, clay coatings, biogenic activity, and diffused impure micritic nodules as PC in the Bw and Bt, Btk horizons. These pedofeatures are more strongly developed in paleosols of the Lower Siwaliks than in comparison to weakly-moderately paleosols of the Middle Siwaliks.Clay mineralogy determined based on XRD study of the total (<2 µm) fine clay (<0.2 µm) fractions of these paleosols is characterized by the dominance of smectite, vermiculite, and mixed-layer minerals in paleosols of the Lower Siwalik. The clay mineral assemblage shows a  decrease in the abundance of smectite and increase of kaolinite towards the transitions to Middle Siwalik at ~10 Ma. This also shows transformation of the smectite and vermiculite to interstratified clays at about ~8 Ma. After ~8.5 – 8.0 Ma, the paleosols are again marked an increase of the amount of smectite, vermiculite, and mixed-layer minerals in paleosols of the Middle Siwalik towards their transitions to Upper Siwalik. The varying intensity of weathering, paleopedogenesis, and clay mineral assemblage of the paleosols in the Lower and Middle Siwalik suggest fluctuating climatic conditions that evolved from initial semi-arid to sub-humid at ~11 Ma that to higher precipitation at ~8.5 to 8 Ma then again to semi-arid to arid conditions at ~6.5 Ma. Keywords: Himalayan Foreland Basin (HFB), Siwalik, Paleosols, Micromorphology, Clay Minerals
The statistical downscaling methods’ uncertainty share as a measure for adopted strategies in downscaling studies for climate change
Authors: Mendoza Paz Santiago , Willems Patrick
Published: February 2023

To study climate change we rely on global climate models (GCMs) but their resolution is coarse to investigate impacts at the local scale. Hence, a downscaling task is required for the use of these coarse-resolution outputs. In this sense, statistical downscaling methods (SDMs) are commonly applied to analyse the local impacts. Furthermore, a quantification of the uncertainty share of the SDMs is advised to complement the results. However, many choices need to be done before their application and these decisions can bias the outcome of the analysis. This work examines the SDMs’ uncertainty share to evaluate to what extent the different adopted strategies can impact the climate change signal (CCS) associated with the study. For this, eleven research indicators (six representing precipitation extremes) are used with four future scenarios, 28 state-of-art GCMs, and 15 SDMs of two different types (change factor and quantile mapping methods). The uncertainty involved is quantified by the variance decomposition procedure. Three different decisions are tested:(i) The selection of the Coupled Model Intercomparison Project (CMIP) era. The uncertainty shares in phases five and six (CMIP5 and CMIP6, respectively) are compared.  (ii) The selection of the SDM ensemble based on the SDMs’ methodological construction. More specifically, based on an ensemble of five methods of change factor type (including an event-based change factor weather generator) and an ensemble of ten methods of quantile mapping.(iii) The selection of the optimal SDM ensemble number. Different unique SDMs combinations are tested from k-ensemble members in [2,n] with n as the ensemble with the largest number of members (n=15).To complement the analysis, the outcomes of the CCSs from all the combinations in (ii) and (iii) are analysed. The results showed that the uncertainty quantification of the SDMs is not sensitive to the selection of the CMIP era. However, this choice is important if the focus is on the GCMs and future scenarios. Hence, it is preferable (but not mandatory) to perform the analysis with the most recent era. The selection of the SDMs based on a methodological construction might bias the conclusions. Therefore, it is better to include methods from all possible types since the results showed that the more methods included in the downscaling, the more reliable the estimation of the SDMs’ uncertainty share. The CCS seems to strongly depend on the choice of the SDM ensemble, and it tends to converge from different k-ensemble members in [2,n] towards the largest ensemble (n). Hence, CCSs from large SDM ensembles will be more reliable. Future work must extend the analysis into different climatological regions and include more methods from all the possible types.
Multifractals, Climate Networks and the extreme variability of precipitation
Authors: Thomas Adarsh Jojo , Kurths Jürgen , Schertzer Daniel
Published: February 2023

Precipitation is a complex process that is extremely variable over a wide range of space-time scales. More specifically, it is strongly intermittent: the heaviest precipitation are increasingly concentrated on sparser and sparser fractions of the space-time domain. At the same time, precipitation is a key variable of urban geosciences. Multifractals have been developed to analyse and simulate across scales this multiscale intermittency, while the climate networks can detect and characterise event synchronisation. In contrast to multifractal analysis, climate networks are usually performed at a given scale, defined by the resolution of the data. In this communication, we present how to overcome this dichotomy and propose multiscale climate networks in the hope of reaching scales relevant to urban geosciences.Specifically, we study theoretically and/or numerically the scale dependance of different centrality measures of climate networks determined at different scales by coarse graining the precipitation data, as is done for multifractal analysis. Among the preliminary results, we show how to modify some of the parameters of the climate networks to force scale invariance of their structure.
River pattern planform dynamics as satellite-derived locational probabilities
Authors: Boothroyd Richard , Williams Richard , Hoey Trevor , Tolentino Pamela , Guardian Esmael , Reyes Juan , Sabillo Cathrine , Quick Laura , Perez John , David Carlos
Published: February 2023

Alluvial rivers adjust their planform as they shift across valley floors, but classification schemes used to describe river patterns often rely on static descriptions of dynamic morphology. River patterns are more diverse and dynamic than sometimes implied by discrete river classification approaches. Here, we quantify satellite-derived locational probabilities for 600 km2 of riverbed in 10 Philippine catchments to explicitly account for lateral dynamism within river pattern classification. We leverage Google Earth Engine (GEE) to apply image-based analyses at large spatial scales and high temporal frequencies. Using archives of Landsat imagery (1988-2019), we assess dynamism across the whole active width of rivers including the wetted channel and unvegetated alluvial deposits. Locational probabilities show the landscape- and reach-scale behaviour of the active river channel. We find that along-valley patterns of river planform mobility are spatially non-uniform; zones of relative stability are interspersed with zones of relative instability. Hotspots of mobility vary in magnitude, size and location between catchments. To better understand the temporality of planform mobility we investigate biennial changes in active river channel extent. In doing so, we re-appraise river pattern as a spatially continuous dynamic metric of fluvial geomorphology; useful for predicting and developing resilience to river-related hazards in dynamic landscapes.
Sediment Disturbance during PMN Mining and Its Impact on Metal Speciation of Sedimentary Cu, Ni, Co in Central Indian Ocean Basin
Authors: Sitlhou Lamjahao , Chakraborty Parthasarathi
Published: February 2023

Deep-sea floors act as reservoir for various marine mineral deposits rich in strategic metal resources important to growth of nation’s economy, national security and the emerging blue economy. Central Indian Ocean Basin (CIOB) is a region with vast marine mineral deposits with a congregation of metals in the form of nodules known as polymetallic nodules (PMN). Government of India signed a 15-year contract with International Seabed Authority (ISA) for exploration of PMN from CIOB. Extensive survey and other scientific developmental activities have been carried out in 75,000km2 area retained by India in CIOB. To conduct mining activities prior to assessment of impact on environment would remark an unwise undertaking. Deep sea mining operation will inevitably impact the surrounding ecosystem due to removal and separation of nodules from soft sediments and increases in suspended finer particles from the altered deep-sea sediment. Disturbances to sediments will have impact on the speciation (labile/inert complexes) of sedimentary metal complexes and may increase metal mobility and bioavailability in marine ecosystem. Study on the possible impact of deep-sea PMN mining requires systematic scientific investigation.This study presents kinetic speciation of metal in surface sediments and their downcore profile.To understand the stability and lability of metals, kinetic speciation study is carried out using ethylenediaminetetraacetic acid (EDTA) as the extracting reagent. Kinetic fractionation studies were performed from two sediments core collected from Test mining site (TMS) and Reference mining site (RMS) in CIOB to determine the metal-sediment complexes and their fate, mobility and bioavailability. Concentration of labile metals complexes and their dissociation rate constant in deep sea sediment can be an index for their bioavailability. It was found that total concentration of Cu and Co gradually decreases, whereas Ni increases in the study area The observed results suggest that the stability of metals-sediment complexes for Cu, Ni, and Co with respect to the depth of the sediment cores gradually increased in the study area. This study suggests that disturbances of deep-sea sediments during PMN mining may not increase labile metals complexes at water-sediment interfaces in the surrounding marine ecosystem. However, results obtained from two sediment cores from Test mine site and Reference mine site respectively may not satisfy representation of the entire 75,000km2 CIOB. Further study is recommended to provide better understanding of the impact of mining activities on marine ecosystem.
The lowermost ELA in the Central Mountain Range of Taiwan during the LGM - dated with TCN
Authors: Böse Margot , Hebenstreit Robert , Hardt Jacob
Published: February 2023

Mountain glaciers are valuable indicators for climate change in the past and present as they react sensitively by variations of their mass balance expressed by the equilibrium line altitude (ELA). The Central Mountain Range of Taiwan represents an exclusive location for palaeo-climate and palaeo-glaciation research in monsoonal East Asia as it provides high altitude terrestrial data in the western Pacific oceanic environment. The presently unglaciated mountains with about 20 mountain massifs above 3000 m altitude have been subject to repeated, multi-stage glaciations during the late Pleistocene and early Holocene. However, traces of glacial processes are only known from a limited number of mountain massifs. The until now studied glacial landforms are restricted to their highest parts (> 3000 m). Glacial deposits or landforms, which can be reliably attributed to the global Last Glacial Maximum (LGM), have not been found in Taiwan  so far. For this study we focused on a relatively low elevated mountain section in the area around the Beishi Shan massif in central Taiwan, where we mapped cirques with over-deepened floors at elevations between 2700 and 2800 m asl, facing to the east. Glacial boulders and rock surfaces of the cirques’ outlets were dated by means of paired (Be-10/ Al-26) in-situ produced cosmogenic nuclides. The derived ages represent the marine isotope stage 2 for boulders near or at the mountain crests above the cirques. Late-glacial to early Holocene ages yielded samples from the cirque outlets. From the data we reconstruct a plateau-like glaciation of this mountain section around the LGM and a subsequent back-melting that resulted in cirque glaciers persisting in favorable downwind-positions until the early Holocene. The orographic ELA was at ca. 2800 m and even lower during the LGM. This is the lowermost ever reported ELA from the Taiwanese mountain range. The east facing cirque positions also imply a great influence of the permanent westerly circulation above the shallow monsoon circulation on the precipitation regime in high altitudes in East Asia.
Monitoring forest canopy structure dynamics from space using GEDI and Sentinel-
Authors: Liu Xiao , Forkel Matthias
Published: February 2023

The distribution of leaves, branches and trunks in the canopy is critical for water, carbon and energy cycles in forests. Light ranging and detection (lidar) and synthetic aperture radar (SAR) are two active remote sensing methods which show the potential to detect forest structure dynamics at different height. Lidar can penetrate the canopy gap and record a reflectivity profile. The vertical distribution of structure metrics, for example, canopy cover, can then be estimated based on this profile. For example, in Amazonian tropical forests, the leaf area index derived using ground- and space-borne lidar at canopy layer and understory layer shows converse behaviour over seasons. For SAR systems, wavelength determines the penetration depth of microwave signal and polarisation reflects the scattering mechanisms between signal and objects. SAR backscatter has been used for monitoring forest phenology and forest classification. However, the potential of using lidar and SAR to monitor canopy structure changes in temperate forests has not been analysed. The relationships between SAR backscatter with the lidar-derived structure metrics at height levels are also not clear.In this study, we attempt to investigate the influence of forest structure at height levels on SAR backscatter in two study sites in Germany: one deciduous forest in Hainich and one coniferous forest in Tharandt. Level 2B product of the Global Ecosystem Dynamics Investigation (GEDI) and Sentinel-1 ground range detected (GRD) backscatter are used in this study. There are dense multi-temporal GEDI observations around 51ºN, which makes it possible to continuously monitor the forest structure at same area. Auxiliary data including digital terrain model, slope, forest type and forest phenology data are used to extract GEDI footprints which cover similar forests. We only focus on GEDI footprints with forest height between 25 m and 30 m since most trees in study sites are distributed in this range and they have distinguishable canopies. Sentinel-1 data with fixed relative orbit is used for mitigating the influence of incidence angle. SAR backscatter at filtered GEDI locations are extracted for comparison.We analyse the correlation between the time series of GEDI-derived total structure metrics (e.g., cover), structure metric profiles and Sentinel-1 backscatter metrics (e.g., VH, VV, VV/VH ratio). For deciduous forest, the 15-20 m layer and 20-25 m layer have stronger correlation to Sentinel-1 VH backscatter and VV/VH ratio than other layers as well as the total structure metric. No significant correlation is found between structure metrics and Sentinel-1 backscatter in coniferous forest. We propose to further develop approaches to investigate the joint potential of space-borne lidar and SAR observations to monitor changes in forest canopy structure.
Seasonal Variation in Stable Isotopes and Physico-chemical Characteristics of AMD Affected Water Bodies in Northeast India
Authors: Kumar Vivek , Paul Dibyendu , Kumar Sudhir
Published: February 2023

The northeastern states of India have extensive deposits of coal among other minerals. Coal mining activities contribute significantly to the economy of these states, providing livelihood to a substantial segment of the populace. Unscientific mining practices have contributed adversely to environmental health of the region, particularly to aquatic systems. Acid mine drainage (AMD) discharge from the mines pollute the streams and rivers, causing serious deterioration of the aquatic environment. Stable isotopes combined with physico-chemical parameters are a promising tool for understanding pollution sources, hydrological processes, factors influencing such processes, and fate of pollutants in hydrological systems. The present study was conducted in AMD affected streams & rivers flowing through the states of Arunachal Pradesh, Nagaland, Assam and Meghalaya in northeast India in two different seasons (pre-monsoon (PRM) & post monsoon (POM)). Water samples were analyzed for 24 physicochemical parameters including the major ions. Stable isotopes of oxygen & hydrogen in water samples were estimated. The results of both sampling seasons are significantly different and reveal that water samples of all sampling sites are dominated by presence of high SO42- in both the sampling seasons; abundance of major ions during PRM are in order SO42->Mg2+>Ca2+>HCO3->Na+>Cl->NO3->K+>NH4+>F- and during POM are in order SO42-> Ca2+>Mg2+>HCO3->Na+>Cl->NO3->K+>NH4+>F-. The stable isotopes of water (δ18O & δD) analysis results indicated enrichment during the POM sampling season. δ18O (‰ V-SMOW)  ranged between -8.60 to -4.95 during PRM and -6.60 to -3.94 during POM, δD (‰ V-SMOW) ranged between -58.29 to -29.63 during PRM and -41.40 to -28.69 during POM. The deuterium excess (d-excess ‰) ranged between 5.70 ~ 17.94 during PRM and 1.57 ~ 14.49 during POM. The hydrochemical characteristics of water during both sampling seasons were deciphered through comprehensive analysis of hydrochemistry (piper diagram, durov plot, gibbs diagram, ion ratios, chadha’s plot) and stable isotopes. The results are discussed.
A Comparative Study of Geothermal Potential of the East and West-Coast Hot Springs, India
Authors: Goswami Susmita , Rai Abhishek
Published: February 2023

Geothermal energy is an important source that has the potential to contribute to the energy needs of society. In this study, we try to understand the hydro-geological characteristics of the hot springs located in the two important coastal terrains of India. i.e., East Coast and West Coast. Our findings indicate that the west coast springs are dominated by Na-Cl, Ca-SO4, and Na-HCO3 water types, indicating that seawater intrusion through deep penetrating faults and fractures may have an impact. The majority of the east coast's hot springs which are located in Odisha have Na-Cl, and Ca-HCO3 water types and a short residence period. According to our findings, hot springs on the west coast have a higher potential compared to Odisha for producing geothermal energy. We find that hot springs on the West Coast are mostly composed of Na-Cl, Ca-SO4, and Na-HCO3 water and that they may be influenced by seawater intrusion. Hot springs on the east coast, particularly in Odisha, have Na-Cl and Ca-HCO3 water and have a short residence period. Some ionic concentrations have a strong correlation, indicating that seawater-rock interactions were dominant in the West Coast and some springs of Odisha thermal springs. The reservoir temperatures for the west and east coast springs, using the saturation-index method is found to be 120±5°C and 110±5°C. The reservoir depths and geothermal fluid circulation depths are estimated to be 1.71 ±0.17km and 1.37±0.32km, respectively. The control of water circulation in hot-spring systems is largely dependent on faults and subsurface high heat flow.  In comparison to Odisha, the West Coast thermal water is heated at a greater depth (1.71±0.17km at 120±5°C); circulation and mixing of thermal water via deeply connected faults and NNW-SSE lineaments. The West Coast springs' reservoir and geothermal fluid circulation depths are greater than those of Odisha, indicating greater circulation.
Impact Chain Assessment for Vulnerability of the School Education System to Climate Hazards in the Sundarbans Delta, India
Authors: Pal Anushree , Tsusaka Takuji W. , Sundaram Mohana , Ahmad Mokbul Morshed , Nguyen Thi Phuoc Lai
Published: February 2023

AbstractThe education sector experiences catastrophic effects of hazards in the form of life losses and school infrastructure damage. Safety of children at school is a global priority, which has also been stressed in the Hyogo Framework for Action (2005-2015) as well as Sendai Framework for Disaster Risk Reduction (SFDRR, 2015-2030). Involvement of school children in disaster risk reduction (DRR) initiatives at the local, regional, and global levels is of paramount importance for resilience development in school education. This research aims to explore the impacts of multiple hazards and associated disruptions in school education, and attempts to identify determinants of resilience of school education to multiple hazards. The various stressors of school education vulnerability will be highlighted through impact chain modeling, which will help in identification of gaps in preparedness of school communities and hence will contribute as a reference for disaster management teams and school communities for better response strategies. The impact chain assessment will be performed through the VenSim model to estimate the degree of cascading impacts on other infrastructure and interdependent systems. The input variables will be defined through the outputs of assessment of climate and anthropogenic stressors for school education vulnerability as well as the evaluation of relationships between social vulnerability and school education.     Keywords: Sundarbans Delta, Climate Hazard, Education System Vulnerability, Impact Chain.
Triggering social accountability for failed groundwater supply infrastructure in rural Malawi: Chiradzulu case study
Authors: Kumwenda Steve , Nhlema Muthi , Ngwira Given , Banda Peter , Nyasulu Tony
Published: February 2023

Key Words: Groundwater Infrastructure, Functionality, Accountability, Right to waterThe Malawi 2018 Sector Performance Report produced by the Ministry of Water and Sanitation found that the proportion of people with access to safe water in the country was 86%, with 57% of improved water points in rural areas being boreholes with hand-pumps. However, a persistent sustainability challenge plagues the water sector: for over 20 years, the functionality of improved water points has remained between 69% and 77%. A study on borehole forensics conducted by the CJF programme found that 30% of hand-pumps fail within five years of installation.Over the past decade hand pump non-functionality has been attributed to poor community ownership and lack of responsibility to manage the operation and maintenance of the wells. However, in some cases this has been merely hypothetical as the non-functionality of some boreholes has been due to factors that are beyond what communities can manage in terms of operation and maintenance.BASEflow with support from the Scottish Government conducted Borehole Forensics, which is a detailed investigation of a borehole and hand pump performance.  Twenty one (21) boreholes were technically assessed and out of these, 13 were found to have unacceptable low yield as per the required Government constant pumping rate test standard of 0.25 liters per second for not less than 4 hours. The failure of the 13 boreholes indicate that the boreholes were developed and constructed to completion and handed over to users when they did not have enough water to meet the required standards.These findings were shared with the relevant stakeholders at Community, District and National level. One major policy recommendation at National level is for the need for adherence to water infrastructure construction standards and the need to empower citizens of rights to water and to hold service providers accountable for failed groundwater supply infrastructure.
Future evolution of glaciers in the Caucasus: focus on debris-cover evolution.
Authors: Postnikova Taisiya , Rybak Oleg , Zekollari Harry , Huss Matthias , Gubanov Afanasy
Published: February 2023

Debris-cover representation is rarely included in regional or global glacier models although it plays a key role in the regulation of melt processes. Debris cover that is more than a few centimeters thick reduces melt by insulating glacier ice. However, mass loss and retreat of debris-covered glaciers are not necessarily slower than those of clear ice. Debris-covered glaciers are widespread in the Northern Caucasus. It is important to reliably quantify their evolution because the contribution of glacial runoff to total discharge is significant in the region.This study assesses the influence of debris cover on the evolution of glaciers in the basins of the Terek and Kuban rivers in the Northern Caucasus in the 21st century and quantifies its effects on glacier mass balance, ice velocity, ice thinning, changes in glacier area, volume, and position of the glacier fronts. We use the GloGEMflow glacier model and introduce a new debris cover dynamic module. The mass balance is calibrated separately for the explicitly modelled debris cover and for clean-ice glaciers (debris cover is implicit in the degree-day factor calibration). The model is calibrated using newly mapped debris cover outlines and ice thickness data from Rounce et al. (2021). The debris evolution is simulated with a steady deposit model adapted from Verhaegen et al. (2020) and Anderson & Anderson (2016), where debris input onto the glacier surface is generated from a fixed point on the flow line.We compare spatio-temporal changes in glacier geometry including the evolution of debris cover for the explicit and implicit debris-cover formulation for five SSP scenarios from CMIP6. The debris-cover evolution patterns differ significantly between the Terek and the Kuban basins. In the Kuban basin, glaciers located generally at lower elevations, retreat rapidly and lose ice at the debris-covered glacier tongues. On the contrary, the supraglacial debris of the Terek basin glaciers may, under certain climate scenarios, expand and play an increasingly-important role in glacier evolution with time. However, under the high-end warming scenario SSP5-8.5, the ice loss by 2100 overwhelms the debris-cover effects in both regions.The maximum difference in glacier length, area and volume depending on the explicit or implicit mode of debris-cover modeling occurs before 2100, but by the end of the century it is eliminated due to the retreat of debris-bearing parts of the glaciers or due to the elevation-stabilization effect. In general, explicitly accounting for debris cover in the projections only has a minor effect on the overall projected regional mass loss, but improves the representation of processes on the intra-glacier scale.This study was carried out under Governmental Order to Water Problems Institute, Russian Academy of Sciences, subject no. FMWZ- 2022-0001, and was funded by the RSF grant number 22-17-00133.
Ambient aerosol variation in India during the COVID-19 lockdown : Simulations from high resolution chemical transport model (CHIMERE)
Authors: Dubey Kanishtha , Verma Dr. Shubha
Published: February 2023

On March 10th 2020, COVID-19 was categorised as a global pandemic by the World Health Organisation (WHO), concerned both by the alarming levels of spread and severity across 114 countries. On account of this, India announced the first nationwide lockdown on 25th March 2020. The present study examines the impact of the lockdown period on the atmospheric levels of overall aerosols (PM2.5) and on individual aerosol species (Black Carbon (BC), Organic Matter (OM), Sulphate (SO42-), Nitrate (NO3-) and Ammonium (NH4+) over the Indian subcontinent using a chemical transport model, CHIMERE. In this study, CHIMERE is forced externally by Weather Research and Forecasting (WRF) model as a meteorological driver in offline mode. The model was run for usual and pandemic lockdown scenarios to estimate the reductions in aerosol species concentration during the lockdown period. The cessation of industrial and transportation activity caused a significant drop in PM2.5 concentration of 20–30% over India, and notably 48% over Delhi. In-land regions saw a sharp decline in PM2.5 concentration (39–48% at Delhi, Bengaluru, and Raipur) compared to coastal locations (11–24% decrease at Kolkata, Mumbai, Chennai, Ahmedabad, and Bhubaneswar), which is explained by the marine influence at those coastal locations. The decrease in measured PM2.5 concentration is very well reproduced by the model for the agricultural state of Telangana, where agricultural residue burning is prominent as a major source of anthropogenic emissions. The elimination of traffic and industrial emissions during the lockdown period resulted in a significant decrease of aerosol species concentration (BC (10-40%), OM (3-10%), SO42- (30-80%), NO3- (70-90%) and NH4+ (60-80%)) over the subcontinent. The study also aims to understand the effect of lockdown on the aerosol optical property and found a reduction of 10-40% in the aerosol optical depth (AOD) over the Indian region. The reductions in the simulated mass concentration of PM2.5 are in eminent agreement (bias ≤ 40%) with the available measurements, rendering the model to be effective for simulating low emission scenarios over India.
Evaluation and application of satellite precipitation products in studying the summer diurnal rainfall events in Taiwan and Luzon
Authors: Huang Wan-Ru , Hsu Jie , Liu Pin-Yi
Published: February 2023

High spatiotemporal resolution satellite precipitation products (herein SPPs) have great potential for investigating rainfall dynamics, including diurnal rainfall (DR). However, the relative performances of these products are regionally specific and unknown in most places. This talk presents our recent works on evaluating and applying various SPPs in studying the summer DR events in Taiwan and Luzon (an Island of Philippines nearby Taiwan). In the first part of the talk, we evaluated the four post-real-time SPPs (including TRMM-3B42 v7, IMERG-F v5, IMERG-F v6, and GSMaP v7) in studying DR events in Taiwan. Our results show that IMERG-F v6 outperforms the other SPPs more accurately (both quantitatively and qualitatively) in depicting the summer rainfall variations in Taiwan at multiple timescales (including mean status, daily, and diurnal), using more than 400 rain-gauge observations as the baseline for comparison. IMERG-F v6 also performs better than other SPPs in capturing the characteristics of DR activities. In the second part of the talk, we further evaluated the near-real-time (NRT) products of IMERG v6 (i.e., IMERG-L and IMERG-E) and GSMaP v7 (i.e., GSMaP-NRT and GSMaP-Gauge-NRT) in depicting the variation in DR in Taiwan. Two sub-components of DR variation, daily mean (Pm) and anomalies (ΔP), were evaluated, and ΔP was further separated into diurnal (S1) and semi-diurnal (S2) harmonic modes. Compared with surface observations, all NRT products underestimated Pm and ΔP; however, IMERG products are relatively better than GSMaP products in most of the examined spatial characteristics. Furthermore, temporal analysis shows that only IMERG-E depicts the phase evolution of both S1 and S2, similar to surface observations. Finally, we showed some potential use of IMERG-F v6 and TRMM-3B42 v7 in studying the long-term changes in the summer DR activities over Luzon and its adjacent seas during 2000-2019.
Effect Of Channel Width on Energy Dissipation Efficiency of Stepped Spillway
Authors: Mishra Ritusnata , Ojha Chandra Shekhar Prasad
Published: February 2023

Abstract: Experimental investigation on flat stepped spillway were conducted with two different width 0.52m and 0.28m on 26.670 slope under nappe flow regimes. The study assessed the rate of energy dissipation at the toe of the spillway for unit discharge, q, ranging from 0.00954m2/s to 0.078854 m2/s for Froude number (Fr) between 0.5 to 0.85. The stepped chute comprised 10 identical steps having 0.10-m step heights and 0.2-m length. It is observed that the rate of energy dissipation at the step edge was relatively observed to be higher in the wider channel. The energy dissipation rate decreased from 3.81% to 26.135% by decreasing the channel width by 46.15% under same unit discharges. It signifies that the width of channel has certain influence on energy dissipation efficiency of spillway under same slope. Therefore, wider channel should be taken for design of stepped spillway under nappe flow regime. The variation in energy dissipation is due to the variation in mean air concentration between two widths. For further validation of these experimental observations, computational fluid dynamics (CFD) models were also used with k-ɛ turbulence model and0.010 m mesh size. Keywords: stepped spillway, energy dissipation, channel width, CFD
Direct Real-Time GHG and ET Measurements for Immediate Societal Benefits: Getting to an AWS-Like Approach with Simple Explanations and CarbonDew
Authors: Burba George
Published: February 2023

Continental-scale research infrastructures and flux networks (e.g., AmeriFlux, AsiaFlux, ChinaFlux, ICOS, NEON, OzFlux), as well as numerous smaller GHG flux networks, and individual sites, measure CO2, CH4, and other GHG exchange, as well as water vapor fluxes (evapotranspiration, ET) between ecosystem and atmosphere.After four decades of academic use, the flux stations covered over 2100 stationary measurement locations, and numerous campaigns’ locations. Most measurements were used for process-level ecological and hydrological studies and long-term climate and ecosystem modeling.Such measurements use ultra-high-resolution methodology and state-of-the-art hardware vastly superior to typical monitoring-grade methods and equipment deployed outside academia for a wide range of non-academic decision-making applications. However, despite providing exceptional ways to measure GHG emissions and ET, these are very rarely utilized outside academia.The key reasons for such lack of utilization are:The perceived complexity of the method - can be resolved via simple-language explanations and a detailed guide described in the presentation
The lack of data in the specific ecosystem or area and the associated expenses required to establish a new station - can be significantly reduced and often resolved by a peer-to-peer cross-sharing concept outlined in the presentation
The absence of a robust overall approach to using flux measurements for immediate societal benefits - can be resolved by adopting an approach currently used by automated weather stations (AWS) feeding and tuning remotes sensing products and resulting in weather modeling and forecasting (see Figure below)
The ultimate goal of this presentation is to ignite and provide a base for a discussion regarding the latest needs, ideas, and examples of the use of flux measurements for practical ‘everyday’ decision-making applications benefiting society. The new Community of Practice “Carbon Dew” is also introduced to address some of these pressing needs.
Characterising the impact of tropical cyclones on mangroves using a multi-decadal Landsat archive
Authors: Asbridge Emma , Lucas Richard , Rogers Kerrylee , Phillips Claire , Krause Claire , Lymburner Leo
Published: February 2023

Tropical cyclones exert a strong driving force for change in mangrove systems. The potential increase in cyclone intensity globally is concerning as this may lead to significant changes in species composition, forest complexity and loss of ecosystem services, including important climate mitigation services. This has implications for the efficacy of blue carbon offsetting in the tropics. There is an urgent need to understand and quantify the effects of cyclones on mangrove ecosystems and the services they provide. The Landsat archive within Digital Earth Australia provides an unprecedented opportunity to quantify cyclone impacts at a national scale and beyond. The aim of this study was to quantify the short- and long-term impacts of Category 3-5 cyclones on mangroves in Australia. This was achieved using wind-field modelling (Geoscience Australia’s Tropical Cyclone Risk Model) and the Landsat archive to a)  establish the degree of recovery in canopy cover of mangroves following cyclones of different category strength; b) quantify the differential response on mangroves, accounting for varying cyclone intensity, mangrove composition, and recovery time since cyclone; and c) conceptualise the likely impacts of future cyclones given predictions of future change, including that associated with anthropogenic driven climatic fluctuation. Windspeeds > 165-224 km/hr, typical of category 3 cyclones, caused the most widespread damage, suggesting a critical windspeed threshold was exceeded. Patterns of short-term damage reflected location and exposure, with the greatest damage observed along open coastlines and fringing forests. Assessments indicated persistent loss of forests when the impact was high over the short-term. Areas experiencing a minor reduction in cover, and to a lesser extent major reduction in cover, exhibited signs of recovery, but the duration of recovery may be prolonged (>10 years). Where cyclones were frequent recovery was impeded by subsequent cyclones, and this may lead to a shift in ecosystem type. The approach used Geoscience Australia’s Open Data Cube and Jupyter Notebooks, which have been published online as open-source code to allow users to repeat the assessments for future cyclones in their area of interest. This is an important feature as Data Cubes are developed and operationalised globally. This analysis demonstrates the utility of Data Cubes for assessing impacts of coastal natural hazards and provides crucial information regarding the long-term resilience of mangroves and their ecosystem services, particularly in the context of a changing climate and variation in cyclone intensity and frequency.
Improving Streamflow Estimates using an Efficient Time Variant Multivariate Assimilation of Soil Moisture and Streamflow Observations
Authors: Visweshwaran Ramesh , Ramsankaran Raaj , T i Eldho
Published: February 2023

During Data Assimilation (DA) in a hydrological model, observations of soil moisture (SM) and streamflow (Q) at interior locations are often assimilated together during the multivariate case to improve streamflow estimates at the catchment outlet. In addition to model states, model parameters need to be updated periodically to account for the variations caused by climatic and human factors during the assimilation period. Therefore, in this study, time-varying multivariate assimilation of ASCAT SM observations and streamflow gauge data from interior sites are ingested into a conceptual two-parameter model, which simulates streamflow using a water budget equation. The Bharathapuzha river basin, lying in the Western Ghats of Southern India is chosen as the study area. In this study, the Ensemble Kalman filter (EnKF), a sequential assimilation approach, is utilized to update the model’s states and parameters at a daily time step. Meanwhile, the computational burden of assimilating such a massive observation needs to be dealt with. A plausible solution is to perform assimilation only at those timesteps when the model is sensitive to the assimilating variable. Consequently, two assimilation scenarios were performed apart from the open-loop (OL) simulations. In the first scenario, all the available SM observations are assimilated irrespective of their sensitivity (DA1). Whereas, in the second scenario, only sensitive SM observations are assimilated into the model (DA2). Results revealed that during both the assimilation scenarios, the model showed improved performance as compared to the open-loop simulations. KGE value improved from 0.68 (during OL) to 0.85 (during DA1) and 0.81 (during DA2). An intriguing fact is that during the second scenario (DA2) when only a subset of sensitive observations was assimilated, the model still showed similar results as DA1. Results highlight that assimilating only spatiotemporally sensitive observations would not affect the model’s performance substantially. Instead, the assimilation efficiency can be enhanced by abbreviating the computational burden.
Can we predict the expected evolution of polar stratospheric clouds on climatic time scales ?
Authors: Leroux Mathilde , Noel Vincent
Published: February 2023

During hemispheric winter a vortex forms on poles resulting in a very sharp drop in stratospheric temperatures. When the temperature drops below a particular threshold TNAT that allows nitric acid nucleation, polar stratospheric clouds (PSCs) can start to form. PSCs are responsible for the thinning of the ozone layer. According to climate models, the ozone layer is expected to return to 1960 levels around 2060. However this progress could be slowed down by enhanced PSC formation due to the cooler and wetter stratosphere that could be caused by climate change. The spaceborne lidar from CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) has helped us understand better the spatial and temporal occurrence of PSCs. The CALIPSO PSC product, derived from CALIPSO level 1B measurements, describes the spatial distribution, optical properties, and composition of PSCs along CALIPSO orbits. The product also includes reanalysis temperatures from MERRA2 and complementary information from the Microwave Limb Sounder (MLS), such as HNO3/H2O mixing ratios which are essential to PSCs formation and to TNAT calculation.In this study we will present a statistical model based on the analysis of the CALIPSO PSC product from 2006 to 2020. It establishes a relationship between the PSC density observed by CALIOP and the density of stratospheric temperatures colder than TNAT. This model allows the prediction of PSC density by pressure level derived from stratospheric temperature. We will show that this model allows us to tell if there is a PSC or not in (2°x4°) boxes over monthly periods, even in places where the satellite CALIPSO doesn't overpass. We will discuss its application on temperatures predicted by Shared Socio-economic Pathways (SSP) scenarios to know the evolution of PSCs over this century. One of our eventual goals would be to investigate if observed PSC densities can constrain stratospheric temperatures predicted by GCMs.  
What controls deltas failure in the Swiss perialpine lakes?
Authors: Vendettuoli Daniela , Strupler Michael , Anselmetti Flavio S. , Fabbri Stefano C. , Shynkarenko Anastasiia , Kremer Katrina
Published: February 2023

Large lacustrine mass movements and delta collapses are increasingly being considered as potential tsunamigenic sources. They are therefore hazardous for the population and infrastructure along lakeshores. In most studies of slope stability and triggered tsunamis, however, subaqueous deltas have largely been excluded as we lack information on their morphodynamic evolution. Thus, a holistic assessment of tsunami hazards in the lacustrine environment is required for a better understanding of how delta lakes evolve through time and space.Within a study funded by the Federal Office of the Environment, we aim to understand what types of deltas are susceptible to slope failure within the perilapine Swiss lakes. To achieve our goal, we primarily focus on those deltas that present an increased potential for subaqueous erosion and analyse their morphological, morphometric and sedimentological characteristics taking advantage of the existing and publically available datasets. In this contribution, we present the designed approach and preliminary results, using Lake Lucerne as a case study. This approach will then be applied to all lakes with a surface area > 1 km2, for which high-resolution bathymetric data are available. The outcomes of such a study will be summarized in a geodatabase of the different delta-types for the perilpine Swiss lakes and it represents an important milestone for the assessment of tsunami hazard with regard to the lakes of Switzerland.