bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting and Monitoring the Activities of Multiple Slow-moving Landslide Areas by the Multitemporal Interferometric SAR (MTInSAR) Technique
Authors: Lu Chiao-Yin , Chan Yu-Chang , Hu Jyr-Ching , Chiu Chun-Ying , Chu Chung-Ray , Tseng Chia-Han , Chang Chih-Hsin
Published: February 2023

Slow-moving landslides can transform into catastrophic landslides at certain conditions. In recent decades, catastrophic landslides around the world have caused widespread damage to buildings and threatened human lives. Thus, the detection of surface displacement variation and the definition of precursory motion for extensive slow-moving landslides become a primary goal of current researches. This study dedicates to detect and monitor surface displacement of multiple slow-moving landslide areas in Taiwan by the multitemporal interferometric SAR (MTInSAR) technique. A new package was established to generate interferograms of multiple slow-moving landslide areas at the same time. Thus, the surface displacement information in large spatial coverage and a long period of time can be obtained efficiently. The landslide characteristics in space and time domain of those slow-moving landslides were investigated and analyzed. Especially, the significant acceleration movements of certain slow-moving landslides were observed and agreed with the in situ monitoring data. The results of this study provide important information of landslide hazard assessment and show the opportunity of detecting the landslide precursory motions by the MTInSAR technique in the future.
Belowground hydraulic resistance generates stomatal closure of grapevine in soil water-limited conditions
Authors: Delval Louis , Jonard François , Javaux Mathieu
Published: February 2023

Climate change will exacerbate drought events in many regions, increasing the demand on freshwater resources and creating major challenges for viticulture. In viticulture, the terroir governs the hydraulic behavior of the vine. The terroir is defined as the interactions between climate, soil, plant material (vine and rootstock varieties) and human management practices. The knowledge on grapevine drought stress physiology has increased significantly in recent years, but a holistic comprehension on how soil-plant hydraulic resistances develop and are regulated remains poorly understood. In particular, how different soil-rootstock combinations and their plasticity affect the vine hydraulic condition is still an open question. The objective of this study is to understand the hydraulics of the soil-plant system in grapevines (Vitis vinifera cv. Chardonnay) in situ, for different soil-rootstock combinations in a temperate oceanic climate, and to investigate its influence on vine water status. The concomitant and automatic monitoring of soil and collar water potentials, as well as sap flow, made it possible to characterize the evolution of the soil-vine hydraulics in situ in real-time, with hourly measurements for two months. In order to investigate the impact of the soil-rootstock combination, two Belgian vineyards with the same variety (cv. Chardonnay) were selected due to their intra-field heterogeneity of soil physico-chemical properties (two study areas per vineyard). The vines of the first vineyard are grafted on the rootstock 3309C and planted on sandy or loamy soils. Those of the second vineyard are associated to the rootstock 101-14Mgt and grow on loamy or silty-clay soils. In each vineyard the soil is therefore the only variable factor, for which hydraulic properties were measured to a depth of 2 m. The measurements were collected between mid-July and mid-September, during a period of exceptional drought in Belgium leading to soil water-limited conditions (rainfall anomaly of -153,8 mm and -148,4 mm in the first and second vineyard respectively over this period). The mean soil-plant conductances observed over the season were respectively 0,54.10-5 cm.s-1.MPa-1 and 2,18.10-5 cm.s-1.MPa-1 in the sandy and loamy areas of the first vineyard, and 1,79.10-5 cm.s-1.MPa-1 and 2,97.10-5 cm.s-1.MPa-1 in the silty-clay and loamy areas of the second vineyard. Despite this extreme drought, the minimum observed stem water potential (Ψstem) was -1,47 MPa (sandy study area of the first vineyard). This is in line with other studies that have shown in situ vines typically work within a safe range of water potentials (Ψstem > -1,5 MPa) that do not lead to cavitation or turgor loss. These first observations validate the hypothesis that the increase of belowground hydraulic resistance triggers stomatal closure of vine.
Sources of Methane Emissions in the Urban Atmosphere - Case Study: Cluj-Napoca City
Authors: Hmoudah Mustafa , Baciu Calin , Pop Cristi
Published: February 2023

Methane is considered to be the second largest contributor to the greenhouse effect after CO2, with a higher increase of its atmospheric concentration over the industrial era compared to other greenhouse gases, as CO2 or nitrous oxide. At least 50% of CH4 emissions come from anthropogenic activities in urban and rural areas, due to the combustion of fossil fuels, waste and wastewater treatment, leaks from the natural gas distribution system, etc.
Although, CH4 is more than 20 times more potent than CO2 in producing the greenhouse effect, it has a short residence time in the atmosphere, which makes the mitigation measures more effective in minimizing these emissions and bringing a short-term advantage to the climate.
Methane concentrations were determined at street-level in the city center, commercial area, residential area, and green area of Cluj-Napoca, Romania. A portable West Systems fluxmeter was used. The instrument is based on Tunable Diode Laser Absorption Spectroscopy, that allows high precision measurements and very low detection limit, of 0.1 ppm.  By eliminating wind effects at street-level, the residential area recorded the least values of these emissions, around the CH4 average atmospheric concentration. Similarly, the emissions in the commercial area were fluctuating around same atmospheric concentration average, but strongly depending on the traffic density. On the sidewalk, at about 1.3 m height, the recorded methane concentrations ranged between 1.9 and 6.0 ppm. The highest values occurred at the passage of heavy vehicles as trucks.
Concentrations of tens or even hundreds ppm CH4 were measured close to the drains that collect water run-off from the streets, and even higher at manhole covers of the sanitary sewerage system.
However, the outcomes of this study indicate the need for further investigation of CH4 emissions in the urban area and the importance of the isotopic characterization of these emissions in order to identify their sources for prioritizing the CH4 mitigation measures.
 
Landslide dams in Europe – distribution, data gaps, and further research
Authors: Mihu-Pintilie Alin , Dufresne Anja
Published: February 2023

The states and territories of Europe extend from the Ural mountains in the East to the Black and Mediterranean Seas in the South and are enclosed by the Atlantic Ocean West and North. With a variety of landscapes prone to slope failures, only few inventories exist of the resulting landslide deposits and river-damming (past and present) locations. In this chapter of the planned Springer Book „Landslide Dams around the World“ we are compiling data from published inventories, search for and add unpublished data, and aspire to present as complete a story as possible of landslide dams in Europe. Whilst extensive inventories exists for Austria, Italy, Norway, and Switzerland, few other countries feature published landslide dam datasets (e.g., Romania). Case studies exist for larger dams and some datasets are stored (but not always available) with regional geological surveys. We hence call for collaboration across Europe to complete the database and pursue the following objectives: (i) create a comprehensive landslide-dam database for the European territory, (ii) statistically analyse the data for clusters, geomorphic and temporal correlations, (iii) identify influencing factors (e.g., regional, climatic, hydrologic, anthropogenic) on landslide-dam occurrence and stability, and (iv) make the data available for researchers and stakeholders alike.
Stability of AOD1B RL07
Authors: Shihora Linus , Liu Zhijun , Balidakis Kyriakos , Dill Robert , Dobslaw Henryk
Published: February 2023

The Atmosphere and Ocean non-tidal De-aliasing Level-1B (AOD1B) product is widely used in satellite gravimetry to correct for transient effects of atmosphere-ocean mass variability that would otherwise alias into monthly-mean global gravity fields. The most recent release is based on the global ERA5 reanalysis and ECMWF operational data together with simulations from the general ocean circulation model MPIOM consistently forced with fields of the same atmospheric data-set.To fully utilise the potential of geodetic data for climate applications, addressing long-term stability in background (or observation-reduction) models is critically important. Spurious trends, low-frequency signals or bias jumps in the background model data can be, if unaccounted for, be introduced into the final gravity solutions and erroneously interpreted in geophysical analyses. We here present the recently published new release RL07 of AOD1B, which is produced from 1975 onwards, and analyse its stability both on long time-scales through the study of trends as well as short-scale stability through the analysis of 3 hourly tendencies. Results are compared to other atmospheric reanalyses and the previous version of AOD1B. A special focus is placed on the transition from ERA5 to ECMWF operational atmospheric data and model changes in ECMWFs IFS.
Modeling the biogeochemical dynamics of a shallow lagoon impacted by intensive shellfish farming (Sacca di Goro, Po river delta, Northern Adriatic Sea).
Authors: Arcamone Roberto , Zavatarelli Marco , Biolchi Luis , Unguendoli Silvia , Valentini Andrea
Published: February 2023

Within the European Interreg Italy-Croatia project “CoAStal and marine waters integrated monitoring systems for ecosystems proteCtion AnD managemEnt (CASCADE)” ( https://www.italy-croatia.eu/web/cascade), an off-line coupled physical-biogeochemical box-model was implemented in the shallow Goro lagoon (northern Adriatic Sea, Po river delta region) in order to study its biogeochemical dynamics. The lagoon is subject to intensive shellfish (Ruditapes Philippinarum) farming: more than one third of the lagoon surface is exploited for clam farming, with an annual production that reached a maximum of approximately 15,000 t y-1 in the early 1990s.The biogeochemical component of the modelling system is the Biogeochemical Flux Model (BFM), accounting for the biogeochemical cycling processes occurring in water and sediments, including (with a functional groups approach) the planktonic and the zoobenthic biota, and fully resolving the benthic pelagic coupling. BFM is implemented in several areas of the lagoon having homogeneous characteristics and different shellfish farming conditions. The areas resolved by the BFM are connected among each other by the mass exchanges (dissolved and particulate) depending by the water circulation in the lagoon that is modeled by the Shallow Water Hydrodynamic Finite Element Model (SHYFEM).The results of the simulation show that the model is able to capture the essential dynamics of the lagoon, with values almost in the same order of magnitude with the measurements from experimental campaigns runned during the project. Particular attention (trough sensitivity experiments) is given to the impact of the the shellfish farming on the lagoon biogeochemical dynamics. The ultimate goal of this work is to provide stakeholders with useful information regarding the evolving biogeochemical conditions that favor the sustainability  of the  shellfish farming.
PETM onset triggered by intense volcanism in the North Atlantic: evidence from tellurium
Authors: Baumann Nils Björn , Regelous Marcel , Regelous Anette , Adatte Thierry , Thibault Nicolas Rudolph , Schultz Bo Pagh , Haase Karsten
Published: February 2023

The Paleocene – Eocene Thermal Maximum (PETM) was a global hyperthermal event during which temperatures increased by 6 - 8° C within a few thousand years at the Paleocene - Eocene boundary, and lasted about 250 ka resulting in ocean acidification, anoxia, and marine extinctions. The PETM coincided with the opening of the North Atlantic and the emplacement of the North Atlantic Igneous Province (NAIP). However, because of the short duration of the PETM compared to NAIP volcanism (several Ma), the contribution of NAIP volcanism to these environmental changes is unclear.Previous studies have used mercury (Hg) enrichments in Paleocene - Eocene sediments as a proxy to link the timing and intensity of NAIP volcanism to the environmental changes at the PETM. However, published Hg and Hg/TOC profiles across the PETM from various locations are different, indicating that Hg is affected by processes other than volcanism. Here we use tellurium (Te), a volatile trace element that is highly enriched in volcanic gas relative to crustal rocks, as an alternative proxy for NAIP volcanism. Te and other trace element concentrations were measured by ICP-MS in sediments from the Fur Formation in Denmark and DSDP Site 550 in the North Atlantic, which span the PETM. Sediments of both study sites are enriched in Te with averages between 200 to 300 ppb and thus exceeding estimated average crustal concentrations of 1 – 5 ppb drastically. In both locations, Te and Te/Nb ratios increase abruptly at the level of the carbon isotope excursion (CIE) onset, remain high during the PETM ‘body’, and decrease towards the end of the main North Atlantic ash phase. The Te variations are not correlated with trace element proxies for anoxia or productivity. The Te data support recent Hg isotope data indicating a brief intense phase of NAIP volcanism initiating at the onset of the δ13C excursion and lasting for a few 100 ka. The coincidence of the main volcanic pulse and the CIE onset suggests that the source of the light carbon may be volcanic, rather than metamorphic.
The aftershock series of the 2016 Petermann Ranges earthquake in Central Australia
Authors: Sippl Christian , Brenn Gregory , Shamsalsadati Sharmin , Tkalčić Hrvoje
Published: February 2023

Although located far from any active plate boundaries, Central Australia features significant seismic activity, with a total of four M>6 events in the last four decades. The most recent such event was the May 25th, 2016 Petermann Ranges earthquake (Mw = 6.1), which occurred close to the border triangle between the Northern Territory, South Australia and Western Australia. The last tectonic reactivation of the region that hosted the earthquake occurred during the intraplate Petermann Orogeny that terminated about 540 Ma ago. It is commonly assumed that although recently inactive, this region still constitutes a lithospheric-scale zone of weakness, so that stresses imposed on the rigid Australian plate at its edges can localize and lead to seismicity here. Previous studies have shown that the Petermann earthquake occurred on a splay fault in the direct vicinity of the Woodroffe Thrust, one of the principal shear zones of the Petermann Orogeny. It occurred at a very shallow depth (<= 5 km) and had a thrust mechanism with a NW-SE oriented rupture plane. Due to its shallow depth, it created a surface rupture that was mapped over a length of about 20 km.In the present study, we utilized a temporary deployment of 11 seismic stations that was installed in the aftermath of the Petermann earthquake to characterize its aftershock sequence. Since only a single permanent station was operating within a radius of 400 km around the rupture area before the deployments, we do not have much information about the earliest part (first two weeks) of the aftershock series.We combine two different event catalogs, a handpicked one comprising 1231 events for the first 3.5 months of the aftershock sequence, and a semi-automatically derived one that contains a total of 4918 events. We derived an optimal 1D velocity model and station corrections from the handpicked catalog, and relocate all events with this model. In a second step, we apply a double-difference relocation to the entire dataset. Most of the relocated events occurred at depths between 2 and 4 km, and outline a tight NW-SE striking an NE-dipping plane that aligns well with the mapped trace of the surface rupture. As already indicated in previous studies, we also find scattered aftershock activity within the footwall of the fault.We further applied a template-matching algorithm in order to further decrease the completeness magnitude of the catalog and to get the best possible estimate for event rate decay over time. Moreover, we present fault plane solutions for a few of the largest aftershocks.
Permeability and seismicity rate changes at an inflating submarine volcano caused by dynamic stresses
Authors: Barkat Adnan , Tan Yen Joe , Xu Guangyu , Waldhauser Felix , Tolstoy Maya , Wilcock William S.D.
Published: February 2023

Our understanding of dynamic earthquake triggering in submarine environments is limited due to the lack of offshore observations. Here, we analyze the triggering susceptibility of a magmatically robust, seismically active submarine volcano (Axial Seamount), located at the intersection of the Juan de Fuca ridge and the Cobb hotspot in the northeast Pacific Ocean. Axial Seamount hosts a cabled network of geodetic and seismic instruments since late 2014. Axial Seamount last erupted in April 2015 and has continued to inflate since. We utilize a high-resolution micro-seismicity catalog to evaluate the triggering response from July 2015 to July 2022 based on seismicity rate change estimates for potential triggering sources. We report statistically significant episodes of dynamic earthquake triggering for ~16% of cases, including instances of both instant (0 < 𝑡 < 2 ℎ𝑟) and delayed (2 < 𝑡 < 24 ℎ𝑟) increases in local earthquake rate following the arrival of teleseismic waves. Initial results do not show any obvious dependence of triggering strength on the amplitude of the peak ground velocity. To evaluate the possible influence of permeability change on dynamic earthquake triggering, we compute the phase lag between vent-fluid temperature and tidal loading for the 3-day periods before and after the arrival of teleseismic waves. We report permeability changes for both triggering and non-triggering cases. Our findings provide useful insights into the physical mechanisms controlling the dynamic earthquake triggering at submarine volcanic environments.
Case study of a groundwater source heat pump at a coastal aquifer
Authors: Shim Byoung Ohan
Published: February 2023

A groundwater source heat pump (GWHP) system for heating and cooling of building is a proven technology which has been adapted worldwide. This system is located at a coastal aquifer consisted of sand and gravel sedimentary layers. The groundwater flow direction towards to coastline and the aquifer thickness is around 24m which is the same depth of pumping and injection wells. The purpose of the GWHP is water heating for a commercial bath facility and the installed heat pump capacity is 396 kW. The groundwater pumping rate is around 1000 m3/day at three wells and the thermally wasted water through heat exchanger reinjects to three injection wells. The pumping tests were conducted to calculate hydraulic parameters. The system operates 6 hours per day with a break of once a month period, and we analyzed the monitoring data of more than one year. At the pumping well the entering water temperatures ranges from 6.0 to 14.7°C, and the groundwater temperature range of injection well is between 2.0 and 8.3°C. From the assumed hydraulic parameters, boundary conditions of operation time, and water levels measured during pumping tests, the groundwater flow and thermal diffusion were simulated by FEFLOW numerical modeling. The simulation model could represent the area of thermal diffusion according to the operation time.  Acknowledgment: This study is conducted by KIGAM basic project ‘Development for Climate Change Adaptation Technologies for Securing and Utilization Large-Scale Groundwater Resources (23-3411)’
Projected amplification of summer marine heatwave intensity in the Northeast Pacific Ocean in a warming world
Authors: Athanase Marylou , Sánchez-Benítez Antonio , Goessling Helge , Pithan Felix , Jung Thomas
Published: February 2023

Marine heatwaves are on the rise: their frequency, intensity, and duration are expected to increase in a warming world. Yet it remains unclear whether local feedback processes could amplify extreme ocean temperatures. A prominent marine heatwave recently occurred in the Northeast Pacific Ocean in summer 2019, exhibiting the highest sea surface temperatures ever recorded in this area since the availability of satellite observations in 1979. Here, we use fully-coupled model experiments, termed “nudged storylines”, in which the evolution of large-scale winds in the free troposphere is nudged to the observed (reanalysed) one before and during the summer 2019 event, to generate close analogues of this record-breaking marine heatwave for past, present, and plausible future climates. We show in particular that future climate analogues of the marine heatwave may warm 50% more than what is expected from the projected global-mean ocean warming. Together with the rapid Northeast Pacific mean warming, air-sea feedback processes lead to a projected warming amplification of 1°C above the 1.9°C global-mean ocean temperature rise. Primary drivers of this amplification are a reduction in clouds and ocean mixed-layer depth, as well as anomalous air advection from fast-warming subpolar regions. Our results show that marine heatwave temperatures may warm substantially faster than the global and regional background temperature, increasing the stress on local ecosystems and fishery resources.
Swarm Absolute Scalar Magnetometer burst mode: from instrument validation to routine observation of intense lightning activity
Authors: Coïsson Pierdavide , Chauvet Louis , Hulot Gauthier , Jenner Martin , Buresova Dalia , Truhlik Vladimir , Chum Jaroslav , Mlynarczyk Janusz , Kubisz Jerzy , Léger Jean-Michel , Jager Thomas
Published: February 2023

Over the past 10 years, the ESA Swarm mission led to many scientific successes sometimes way beyond its primary science targets. One such example is the unanticipated science allowed by the experimental 250 Hz burst mode magnetic scalar data provided by the Absolute Scalar Magnetometers on board the satellites. This burst mode was originally meant to be run briefly for in-orbit calibration and validation activities during the initial months of the Swarm mission. However, and despite the fact that the 250 Hz sampling rate can only access the ELF part of the electromagnetic spectrum, numerous whistler signals could be detected. After carefully assessing the possibility of routinely detecting and characterising such whistlers, it was thus next decided to conduct campaigns of one-week duration every month on Swarm Alpha and Bravo. These started in 2019 and still continue today, the corresponding Burst mode data now being a routine product of the mission.In this presentation, we will review the main scientific results of these campaigns: geographical and temporal distribution of whistler events as well as the detectability of whistler signals, which we assessed using joint campaigns on the Alpha and Bravo satellites during the recent counter-rotating phase of the Swarm mission. Using ground ionosondes and in-situ electron density measurements we also demonstrated the promising possibility of using whistlers to measure ionosphere plasma density parameters along their path up to the Swarm satellites. Finally, using data from the ground based ELF measurements from WERA, and data from the lightning detection network WWLLN, the originating strikes could also be identified. We found that only the most powerful lightning strikes produce detected whistlers, and that these strikes can sometimes occur several thousands of kilometres away from the satellites.
Global warming induces more internally generated extremes of North Atlantic Oscillation and East Atlantic pattern
Authors: Liu Quan , Jungclaus Johann , Matei Daniela , Bader Juergen
Published: February 2023

Increased weather and climate extreme events are often attributed solely to either human-induced climate change or internal variability, under the assumption that external forcing does not influence the internal variability. However, with the development of single-model initial-condition large ensembles, recent research shows the impact of global warming on internal variability. This study investigates how global warming influences the North Atlantic Oscillation (NAO) and the East Atlantic (EA) pattern, which are the dominant large-scale circulation/teleconnection modes in the North Atlantic sector.The study analyzes the geopotential height data of the Max Planck Institute Grand Ensemble (MPI-GE)  with 100 ensemble members. The internal variability is quantified as the deviation from the ensemble mean. The influence of global warming on the internal variability is checked with a 1pcCO2 experiment, where the  concertation is increased by 1% every year. This experiment provides a scenario for relatively strong global warming based on increasing greenhouse gas concentration alone. The extreme NAO and EA are defined as those years where the indexes are above (positive extremes) or below (negative extremes) 2 standard deviations.The results show increases in extreme events, especially negative extremes, for both NAO and EA during wintertime, in a warmer climate. While NAO extremes increase consistently across the whole troposphere, EA extremes increase more at higher altitudes (500hpa-200hpa) than at lower altitudes. The warming effect of positive extreme NAO over northern Eurasia gets weaker, while the cooling effect of negative extreme NAO over northern Eurasia gets stronger. The effects of both, positive and negative extremes of EA, extend eastward till Eastern Asia. Overall, this study underlines the impact of global warming onto the internal variability of NAO and EA.
Emerging signals of a global drift in forest resilience under climate change
Authors: Forzieri Giovanni , Dakos Vasilis , G Mc Dowell Nate , Alkama Ramdane , Cescatti Alessandro
Published: February 2023

The persistence and functionality of forest ecosystems are highly dependent on their resilience to the ongoing rapid changes in climate conditions and in natural and anthropogenic pressures. Experimental evidences of a sudden increase in tree mortality across different biomes are rising concerns about the ongoing changes in forest resilience. However, how forest resilience, which is the capacity to withstand and recover from perturbations, is evolving in response to global changes is not yet explored. Here, we integrate satellite-based vegetation indices with machine learning to show how forest resilience, quantified in terms of critical slowing down indicators, has changed over the period 2000-2020. We show that tropical, arid and temperate forests are experiencing a significant decline in resilience, likely related to the increase in water limitations and climate variability. On the contrary, boreal forests show an increasing trend in resilience, likely for the benefits of climate warming and CO2 fertilization in cold biomes, which may outweigh the adverse effects of climate change. These patterns emerge consistently in both managed and intact forests corroborating the existence of common large-scale climate drivers. Reductions in resilience are statistically linked to abrupt declines in forest productivity, occurring in response to a slow drifting toward a critical resilience threshold. We estimate that about 22% of intact undisturbed forests, corresponding to 3.32 Pg C of GPP, have already reached such critical threshold and are experiencing a further degradation in resilience. Altogether, these signals reveal a widespread and increasing instability of global forests and should be accounted for in the design of land-based mitigation and adaption plans.
The influence of modes of variability and their interplay on compound extreme wind and precipitation events in the northern hemisphere.
Authors: Teber Khalil , Francois Bastien , Gimeno-Sotelo Luis , Küpfer Katharina , Brett Lou , Leeding Richard , Yavuzdogan Ahmet , Domeisen Daniela , Suarez Laura , Bevacqua Emanuele
Published: February 2023

Countless climate-related impacts are caused by compound events, i.e. by the combination of multiple climate processes at different spatial and temporal scales. For example, when precipitation and wind extremes coincide, the resulting impacts on infrastructure and humans can be very destructive. It is established that climate modes of variability, which are known to oscillate from seasonal to decadal timescales, such as the El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Pacific-North American Pattern (PNA) and Atlantic Multidecadal Variability (AMV) favour the occurrence of extreme weather events such as heavy precipitation in several areas worldwide. However, little is known about the effect that these climate modes of variability have on compound events. In this context, understanding the physical modulators of compound events can contribute to an improved comprehension of their dynamics, and ultimately to a better prediction of their impacts. Here, focussing on compound wind and precipitation extremes, we contribute to closing this research gap by using large ensemble climate model simulations (CESM) and reanalysis data (ERA5). We identify hotspot regions in the northern hemisphere where winter (DJF) compound event occurrences are influenced by modes of variability. We also inspect whether particular combinations of modes of variability, e.g., superposition of extreme states of both ENSO and NAO indices, enhance compound event occurrences. Finally, the identified patterns in the observational data are compared to the model simulations. The findings allow us to understand whether climate modes of variability favour the simultaneous occurrence of compound events over different regions worldwide, and how well the current generation of climate model simulations represents these dynamics.  An improved understanding of these oscillating modes of variability could be used to enhance the development of sub-seasonal to seasonal forecasts of compound events, which therefore may reduce their impacts. 
Carbon footprint scenarios for electricity mix in China
Authors: Yang Jin , Tang Lin
Published: February 2023

The biggest increase in carbon emissions took place in the power sector, accounting for more than 40% of global carbon emissions. Identifying critical sectors of carbon emissions in the upstream power sector and mapping out emission reduction pathways are core components of achieving supply chain-wide carbon reductions in China. However, the path to achieving supply chain-wide carbon reductions in China from the provincial perspective is still unclear. This study quantifies the embodied carbon emissions of different power generation technologies by region using a multi-regional input-output-based hybrid approach. The critical upstream sectors that indirectly drive or transport large amounts of carbon emissions through supply chains are identified using both consumption-based and betweenness-based methods. The changes in supply chain-wide carbon emissions of the power sector by region under different emission reduction policy scenarios are also examined. The results indicate that the solar power sector brings the highest carbon reduction benefits, with an average carbon intensity of 1.25 t/10000 yuan. Significant differences in embodied carbon intensity across provinces for the same type of power generation sector are observed, and there is a mismatch between current installation and carbon reduction targets in the coal-fired and wind power sectors. Critical sectors of carbon emissions in the upstream power sector are concentrated in the energy sector and energy-intensive sectors, while the electrical machinery and equipment sector is also key to alleviating environmental pressures as an important upstream carbon transmission sector. Besides, the implementation of the "Replacing Small Generation Units with Large Ones" policy at the provincial level, especially in northwest China, and “further enhancing the supply capacity of clean energy” can effectively promote the emission reduction of the whole supply chain in the power sector. The results presented in this paper may provide a reference for the provincial government to rationally plan future low-carbon transformation paths of the power sector.
Compound dry–hot seasons in Europe – climate change scenarios and uncertainties
Authors: Lhotka Ondřej , Bešťáková Zuzana , Kyselý Jan
Published: February 2023

Compound effects of drought and heat are regarded as one of the largest hazards in relation to climate change. Characteristics of dry–hot seasons in Europe are studied in an ensemble of CORDEX regional climate models (RCMs). Evaluation against the E–OBS gridded dataset for 1976–2005 shows that the RCMs are able to reproduce the spatial pattern of the dry–hot season length but the seasons tend to start later and interannual variability of their length is often underestimated. Changes in the median length of dry–hot seasons (compared to the 1976–2005 simulated climate) are analysed for three future time slices (2006–2035, 2036–2065, and 2066–2095) and low and high greenhouse gas concentration pathways. Preliminary results show distinct prolongations of dry–hot seasons for 2036–2065 in the Mediterranean and Western Europe (+10–30 days), regardless the concentration pathway. The lengths of dry–hot seasons are projected to be similar in the 2036–2065 and 2066–2095 time slices under the low concentration pathway but the RCMs simulate major prolongations of dry–hot seasons in the high concentration scenario over large parts of Europe (+20–50 days), indicating substantial changes in future European hydroclimate.  
Characterization of Indian Summer Monsoon Drought and its Elevation Dependance over Indus River Basin, India
Authors: Dubey Amit , Swami Deepak , Gupta Vivek , Joshi Nitin
Published: February 2023

Drought, a natural disaster, possess a great threat to a nation as well as to human society by stressing the water availability, agricultural production and economy of the country. As per the studies, India is highly vulnerable to droughts, occurring once in every three years from the past three decades. India receives 70-80% of its annual mean precipitation brought by south-west summer monsoon. Monsoon failure leads to the acute deficiency of available water that ultimately causes droughts and water scarce conditions. This study is an attempt to analyse the spatio-temporal variations of meteorological drought and to investigate the effect of topographical variable (elevation) on Indian summer monsoon drought characteristics over Indus River Basin. Indian extent of Indus River basin has been considered as a case. Heterogeneity of the elevation spread over the basin makes it suitable for the study. Therefore, to serve the purpose, daily gridded precipitation and temperature data at a spatial resolution of 0.120 x 0.120 for a time period of 42 years (1979-2020) is utilized to analyse the drought characterization. Modified Mann-Kendall method and Sen’s slope estimator have been used to detect significant trends in the study region. Standardized Precipitation Evapotranspiration Index (SPEI) has been employed to identify the dry events on the basis of climatic water-balance. Indian summer monsoon lasts for four months (June-September), thus SPEI-4 has been computed to characterize the summer monsoon droughts. Results revealed that around 18% (5%) of the stations shows wetting (drying) trends for the monsoon time series analysis. Additionally, in relation to SPEI trends, larger area (25%) of the basin depicts increasing precipitation and decreasing Potential Evapotranspiration (PET) trends. Moreover, the study region experiences 1-10% and 1-5% severe and extreme drought frequency (percentage) respectively over the time period 1979-2020. Further, the relationship of SPEI trend with respect to elevation is explored because highlands are more vulnerable to climate change as compared to low altitude regions. In case of altitude up-to 2000 m, Sen’s slope exhibits positive magnitude thus, wetting trend is observed. A very minimalistic drying trend is seen between 2000-3000 m elevation and beyond that almost no trend pattern is followed. The possible causes of this certain behaviour of SPEI trend with elevation is determined by further analysis of trend of meteorological parameters (precipitation and PET) that were used to calculate SPEI. Both precipitation and PET trends are found to be responsible for the SPEI trends.
Aerosol optical depth validation and aerosol identification using satellite and ground-based data over the high-mountain protected area of Sierra Nevada (Spain)
Authors: del Águila Ana , Alcaraz-Segura Domingo , Martínez-López Javier , Navas-Guzmán Francisco
Published: February 2023

High-mountain protected areas are of great interest from the ecological perspective and have a strong impact on the socioeconomic system. However, protected areas such as National Parks, are scarcely investigated from the climatological point of view. Furthermore, the aerosol loading at high elevation locations is not fully characterized. Thus, the analysis of the aerosol optical depth (AOD) in these areas is crucial to assess the role of aerosols in regional climate change and in several ecosystem processes.We have analyzed the long-term AOD ground-based and satellite remote sensing data in order to provide an accurate picture of the aerosol loading from local to regional scale, respectively. In addition, reanalysis data has been used to provide information of the aerosol typing at larger scale. The Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 global Multi-Angle Implementation of Atmospheric Correction (MAIAC) (hereafter MODIS+MAIAC) provides daily AOD data at 1 km spatial resolution. The ground-based AOD dataset is obtained from the Aerosol Robotic Network (AERONET) over Granada (South-Eastern Iberian Peninsula) and the high-mountain protected area of Sierra Nevada. Specifically, there are three AERONET stations in the region of interest: Granada at 680 m above sea level (a.s.l), Cerro Poyos at 1809 m a.s.l. and Albergue UGR at 2500 m a.s.l., which have been used for validation. Additionally, the latest reanalysis data from MERRA-2 has been employed for aerosol typing at regional scale, with a spatial resolution of 55 km x 69 km, covering the city of Granada and Sierra Nevada high-mountain protected area.In this study, we will present the validation results of AODs from MODIS+MAIAC and MERRA-2 against AERONET stations at different altitudes. Moreover, a trend analysis of the AOD for the long-term database at the different seasons is investigated. Finally, the classification of the major aerosol types at regional scale has been performed, indicating the dominant aerosol types and the increase of Saharan dust events in the recent years over the high-mountain protected area of Sierra Nevada.
Long-term changes in the pore and runoff water quality in restored boreal peatlands
Authors: Päkkilä Lassi , Marttila Hannu , Korhonen Petra , Ikkala Lauri , Kareksela Santtu , Ronkanen Anna-Kaisa
Published: February 2023

In Finland over half of the mire habitat types are endangered mainly due to drainage-induced succession towards more forested type ecosystems. Restoration is thought to be an important tool to improve the status of degraded peatlands. National and European Union level strategies to improve nature conservation have a target of increasing the allocation of restoration actions to peatlands in Finland. Thus, the effects of peatland restoration need to be understood.Peatland drainage lowers the water table and exposes peat to decomposition. Restoration aims to raise the water table, but it simultaneously causes a new disturbance to surface layers often resulting in elevated nutrient and organic carbon concentrations in pore and runoff waters. Typically, the water quality disturbance starts to dampen out in the subsequent years after restoration. The rate and disturbance level depend on e.g., the actual measures, peatland type, and trophic level. To minimize and avoid impacts as well as to find the best restoration practices, knowledge of the long-term (over 10 years) effects of restoration measures is needed.The hydrology of drained and restored peatlands and pristine counterpart mires have now been monitored for almost 15 years in the Parks and Wildlife Finland’s (Metsähallitus) peatland monitoring network. The data consists of high-frequency water table data and pore water quality measurements (four times per growing season) from 46 sites all over Finland with varying nutrient levels and openness (as one of the key indicators for peatland type). Additionally, ten sites have been tested for surface peat quality. Runoff water quality and quantity have been monitored in three of the pristine and five drained and restored sites. In this study, we report the long-term effects of peatland restoration on the water table and water quality in different peatland types. We also focus on understanding the connection of water quality variation in pore and runoff waters, intending to simplify the practical evaluation of peatland restoration success.
Reservoir water quality deterioration due to deforestation emphasizes the indirect effects of global change
Authors: Rode Michael , Kong Xiangzhen , Ghaffa Salman , Determann Maria , Friese Kurt , Jomaa Seifeddine , Mi Chenxi , Shatwell Tom , Rinke Karsten
Published: February 2023

Deforestation is currently a widespread phenomenon and a growing environmentalconcern in the era of rapid climate change. In temperate regions, it is challenging toquantify the impacts of deforestation on the catchment dynamics and downstreamaquatic ecosystems such as reservoirs and disentangle these from direct climatechange impacts, let alone project future changes to inform management. Here, wetackled this issue by investigating a unique catchment-reservoir system with tworeservoirs in distinct trophic states (meso- and eutrophic), both of which drain into thelargest drinking water reservoir in Germany. Due to the prolonged droughts in 2015-2018, the catchment of the mesotrophic reservoir lost an unprecedented area of forest(exponential increase since 2015 and ca. 17.1% loss in 2020 alone). We coupledcatchment nutrient exports (HYPE) and reservoir ecosystem dynamics (GOTM-WET)models using a process-based modelling approach. The coupled model was validatedwith datasets spanning periods of rapid deforestation, which makes our futureprojections highly robust. Results show that in a short-term time scale (by 2035),increasing nutrient flux from the catchment due to vast deforestation (80% loss) canturn the mesotrophic reservoir into a eutrophic state as its counterpart. Our resultsemphasize the more prominent impacts of deforestation than the direct impact ofclimate warming in impairment of water quality and ecological services to downstreamaquatic ecosystems. Therefore, we propose to evaluate the impact of climate changeon temperate reservoirs by incorporating a time scale-dependent context, highlightingthe indirect impact of deforestation in the short-term scale. In the long-term scale (e.g.to 2100), a guiding hypothesis for future research may be that indirect effects (e.g., asmediated by catchment dynamics) are as important as the direct effects of climatewarming on aquatic ecosystems.
DELWAVE 1.0: Deep-learning surrogate model of surface wave climate in the Adriatic Basin
Authors: Mlakar Peter , Ricchi Antonio , Carniel Sandro , Bonaldo Davide , Licer Matjaz
Published: February 2023

We propose a new DEep Learning WAVe Emulating model (DELWAVE) which successfully emulates the behaviour of a numerical surface ocean wave model SWAN, thus enabling numerically cheap large-ensemble prediction over synoptic to climate timescales. DELWAVE training inputs consist of 6-hourly surface COSMO-CLM wind fields during period 1971 - 1998, while its targets are surface wave significant wave height, mean wave period and mean wave direction. Testing input set consists of surface winds during 1998-2000 and cross-validation period is the far-future climate timewindow of 2071-2100. Several detailed ablation studies were performed to determine optimal performance regarding input fields, temporal horizon of the training set and network architecture. DELWAVE reproduces SWAN model significant wave heights with a mean absolute error (MAE) between 5 and 10 cm, mean wave directions with a MAE of 10-25 degrees and mean wave period with a MAE of 0.2 s. SWAN and DELWAVE time series are compared against each other in the end-of-century scenario (2071-2100), and compared to the control conditions in the 1971-2000 period. Good agreement between DELWAVE and SWAN is confirmed also when considering climatological statistics, with a small (5%), though systematic, underestimate of 99th percentile values. Compared to control climatology, the mismatch between DELWAVE and SWAN is generally small compared to the difference between scenario and control conditions, suggesting that the noise introduced by surrogate modeling is substantially weaker than the climate change signal.
Substantial Errors Revealed When Calculating Heat Stress Using Grid Cell Averages as Compared to Sub-Grid Cell Environments
Authors: Buzan Jonathan , Joos Fortunat
Published: February 2023

We implement the Wet Bulb Globe Temperature (WBGT), a standardized heat stress metric, into the Community Land Model (CLM5), the land surface component of the Community Earth System Model (CESM2). This includes the notoriously difficult calculation related to measuring human heat stress: radiation. Following the International Organization for Standardization (ISO) 7243, physical representations of the instruments, a globe thermometer and natural wet bulb thermometer, simulate where humans work and live in non-urban environments. By using ISO 7243 within CLM5, we create a common framework within Earth system models to calculate the impact of radiation on temperature-moisture covariance. We demonstrate the capabilities of the WBGT using a default configuration of CLM5. We output 4x daily temporal resolutions globally, showing the advantage of simulating the WBGT within each environment. The WBGT outdoor and indoor calibration is simulated in an averaged grid cell, above the vegetation canopy, below the vegetation canopy, and bare ground environments. We examine the 1995 Chicago Heatwave, specifically the rural regions impacted by the heatwave, and demonstrate that the grid cell average calculated at the CLM5 30-minute time step is a poor representation of human environments and can differ by multiple degrees. In high heat stress environments following ISO 7243, a 0.5C change in WBGT can lead to a >10% reduction in labor capacity. This difference in temperature and labor capacity shows that assumptions about calculating a non-linear algorithm — even utilizing high temporal frequency grid cell averages that drive non-linear labor capacity impact models — is a flawed approach that can grossly over or underestimate the impact of heat stress on future climate change projections. To accurately assess the direct exposure, risk, and damage of climate change on people, it is critical to implement diagnostics directly into Earth system models.