bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of uplift and subsidence along the North American Pacific coast – illuminating the geodynamic complexity of an active margin
Authors: Yousefi Maryam , Milne Glenn , Li Shaoyang , Wang Kelin , Bartholet Alan , Love Ryan , Tarasov Lev
Published: March 2021

The Pacific Coast of Central North America is a geodynamically complex region subject to various geophysical processes with different patterns of vertical land motion. It includes two distinct tectonic regimes: the Cascadia subduction zone and the strike-slip San Andreas fault system. The vertical land motion in this region reflects not only tectonic activity of these plate boundaries, but also isostatic signals associated with different loading effects such as the (de)glaciation of North American ice sheets and the more contemporary, anthropogenically-related groundwater extraction and mountain glacier mass loss. These processes occur over a broad range of timescales and are observed by a variety of measuring techniques.

Here we combine geological measurements of relative sea level (RSL) change with contemporary observations of vertical land motion inferred from geodetic data to decipher and thus better understand the contribution from various individual processes. Our results suggest that contemporary vertical land motion is dominated by Cascadia interseismic deformation and the isostatic response to the retreat of the North American ice sheets but is also influenced by other contemporary processes. We present some model results that illustrate the contributions of the above-mentioned processes to RSL projections along this coastline.  
Using the 3D MOCAGE CTM to simulate the chemistry of halogens in the volcanic plume of Etna's eruption in December 2018 at the regional scale
Authors: Narivelo Herizo , Marécal Virginie , Hamer Paul David , Surl Luke , Roberts Tjarda , Bacles Mickaël , Warnach Simon , Wagner Thomas
Published: March 2021

Volcanoes emit different gaseous species, SO₂ and in particular halogen species especially bromine and chlorine compounds. In general, halogens play an important role in the atmosphere by contributing to ozone depletion in the stratosphere (WMO Ozone assessment, 2018) and by modifying air composition and oxidizing capacity in the troposphere (Von Glasow et al. 2004). The halogen species emitted by volcanoes are halides. The chemical processing occurring within the plume leads to the formation of BrO from HBr following the ‘bromine explosion’ mechanism as evidenced from both observations and modelling (e.g., Bobrowski et al. Nature, 2003; Roberts et al., Chem. Geol. 2009). Oxidized forms of chlorine and bromine are modelled to be formed within the plume due to the heterogenous reaction of HOBr with HCl and HBr, forming BrCl and Br₂ that photolyses and produces Br and Cl radicals. So far, modelling studies were mainly focused on the very local scale and processes occurring within a few hours after eruption.

In this study, the objective is to go a step further by analyzing the impact at the regional scale over the Mediterranean basin of a Mt Etna eruption event. For this, we use the MOCAGE model (Guth et al., GMD, 2016), a chemistry transport model run with a resolution of 0.2°x 0.2°, to quantify the impacts of the halogens species emitted by the volcano on the tropospheric composition. We have selected here the case of the eruption of Mount Etna around Christmas 2018 characterised by large amounts of emissions over several days (Calvari et al., remote sensing 2020; Corrdadini et al., remote sensing 2020). The results show that MOCAGE represents rather well the chemistry of the halogens in the volcanic plume because it established theory of plume chemistry. The bromine explosion process takes place on the first day of the eruption and even more strongly the day after, with a rapid increase of the in-plume BrO concentrations and a corresponding strong reduction of ozone and NO2 concentrations.

We also compared MOCAGE results with the WRF-CHEM model simulations for the same case study. We note that the tropospheric column of BrO and SO₂ in the two models have the same order of magnitude with more rapid bromine explosion occurring in WRF-CHEM simulations. Finally, we compared the MOCAGE results to tropospheric columns of BrO and SO2 retrieved from TROPOMI spaceborne instrument.
Atmospheric, oceanic, and sea-ice variability along Nares Strait: a numerical model study
Authors: Garcia Quintana Yarisbel , Myers Paul G. , Moore Kent
Published: March 2021

Nares Strait, between Greenland and Ellesmere Island, is one of the main pathways connecting the Arctic Ocean to the North Atlantic. The multi-year sea ice that is transported through the strait plays an important role in the mass balance of Arctic sea-ice as well as influencing the climate of the North Atlantic region. This transport is modulated by the formation of ice arches that form at the southern and northern of the strait.  The arches also play an important role in the maintenance of the North Water Polynya (NOW) that forms at the southern end of the strait. The NOW is one of the largest and most productive of Arctic polynyas. Given its significance, we use an eddy-permitting regional configuration of the Nucleus for European Modelling of the Ocean (NEMO) to explore sea-ice variability along Nares Strait, from 2002 to 2019. The model is coupled with the Louvain-la-Neuve (LIM2) sea ice thermodynamic and dynamic numerical model and is forced by the Canadian Meteorological Centre’s Global Deterministic Prediction System Reforecasts.

We use the model to explore the variability in ocean and sea ice characteristics along Nares Strait. The positive and negative degree days, measures of ice decay and growth, along the strait are consistent with the warming that the region is experiencing. Sea-ice production/decay did not show any significant change other than an enhanced decay during the summers of 2017-1019. Sea-ice thickness on the other hand has decreased significantly since 2007. This decrease has been more pronounced along the northern (north of Kane Basin) portion of the strait. What is more, ocean model data indicates that since 2007 the northern Nares Strait upper 100m layer has become fresher, indicating an increase in the freshwater export out of the Arctic Ocean and through the strait. The southern portion of the strait, on the other hand, has become warmer and saltier, which would be consistent with an influx of Irminger Water as proposed by previous modelling results. These changes could impact the formation and stability of the ice arch and hence the cessation of ice transport down Nares Strait as well as contributing to changes in the characteristics of the NOW. 
How good does Automatic Model Structure Identification work? A Benchmark Study with 6915 Model Structures.
Authors: Spieler Diana , Schütze Niels
Published: March 2021

Recent investigations have shown it is possible to simultaneously calibrate model structures and model parameters to identify appropriate models for a given task (Spieler et al., 2020). However, this is computationally challenging, as different model structures may use a different number of parameters. While some parameters may be shared between model structures, others might be relevant for only a few structures, which theoretically requires the calibration of conditionally active parameters. Additionally, shared model parameters might cause different effects in different model structures, causing their optimal values to differ across structures. In this study, we tested how two current “of the shelf” mixed-integer optimization algorithms perform when having to handle these peculiarities during the automatic model structure identification (AMSI) process recently introduced by Spieler et al. (2020).

To validate the current performance of the AMSI approach, we conduct a benchmark experiment with a model space consisting of 6912 different model structures.  First, all model structures are independently calibrated and validated for three hydro-climatically differing catchments using the CMA-ES algorithm and KGE as the objective function. This is referred to as standard calibration procedure. We identify the best performing model structure(s) based on validation performance and analyze the range of performance as well as the number of structures performing in a similar range. Secondly, we run AMSI on all three catchments to automatically identify the most feasible model structure based on the KGE performance. Two different mixed-integer optimization algorithms are used – namely DDS and CMA-ES. Afterwards, we compare the results to the best performing models of the standard calibration of all 6912 model structures.

Within this experimental setup, we analyze if the best performing model structure(s) AMSI identifies are identical to the best performing structures of the standard calibration and if there are differences in performance when using different optimization algorithms for AMSI. We also validate if AMSI can identify the best performing model structures for a catchment at a fraction of the computational cost than the standard calibration procedure requires by using “off the shelf” mixed-integer optimization algorithms.

 

 

 

Spieler, D., Mai, J., Craig, J. R., Tolson, B. A., & Schütze, N. (2020). Automatic Model Structure Identification for Conceptual Hydrologic Models. Water Resources Research, 56(9). https://doi.org/10.1029/2019WR027009
Essential Role of Mid-latitude Air-Sea Interactions over the North Atlantic and North Pacific in the Occurrence of Euro-Atlantic Blocking
Authors: Cheung Ho-Nam , Omrani Nour-Eddine
Published: March 2021

Atmospheric blocking (“blocking”) is a crucial dynamic driver of extreme weather (e.g., severe/long-lasting cold spells, heat waves, drought and flood) over the extratropical region, where blocking occurs most frequently in boreal winter over the Euro-Atlantic and North Pacific sectors. In the state-of-the-art climate models, however, blocking frequency over the mid-latitude Euro-Atlantic sector is generally underestimated. Recent studies have pinpointed the importance of air-sea interactions over the North Atlantic in the formation of Euro-Atlantic blocking. In this study, we will demonstrate that the occurrence of Euro-Atlantic blocking is also related to the remote forcing from the North Pacific. Based on novel semi-idealized atmospheric general-circulation model experiments, we depict the impact of tropical and extratropical SST over different basins on the physical processes of Euro-Atlantic blocking events. We will show that the SST fronts over the mid-latitude North Atlantic and North Pacific jointly contribute to the occurrence of Euro-Atlantic blocking, whereas the contribution of tropical SST is relatively small. A budget analysis of the vorticity equation reveals that both high-frequency (< 8 days) and low-frequency (> 8 days) forcing contribute to the formation of Euro-Atlantic blocking events. The high-frequency forcing is associated with the intensification of an extratropical cyclone over the northwestern/central Atlantic, which is related to the North Atlantic storm tracks. The low-frequency forcing is associated with the eastward propagation of a Rossby wavetrain from North America to the Euro-Atlantic region. We will demonstrate how these physical processes are attributed to the North Atlantic and North Pacific SST fronts. Overall, our results provide new insights into the fundamental dynamics of Euro-Atlantic blocking events.
Can We Measure a COVID-19 Related Slowdown in Atmospheric CO2 Growth? Sensitivity of Total Carbon Column Observations
Authors: Sussmann Ralf , Rettinger Markus , Hase Frank , Roehl Coleen
Published: March 2021

The COVID-19 pandemic caused annual CO2 emission reductions estimated up to -8 % for 2020. This approximately matches reductions required year-on-year to fulfill the Paris agreement. We pursue the question whether related atmospheric concentration changes may be detected by the Total Carbon Column Observing Network (TCCON), and brought into agreement with bottom-up emission-reduction estimates. We present an original mathematical framework to derive annual growth rates from TCCON observations. Our approach guarantees robust results for the non-equidistant  (clear-sky) sampling of solar absorption measurements of column-averaged carbon dioxide (XCO2) and it includes for the first time a mathematically rigorous uncertainty calculation for annual growth rates. The min-max range of TCCON growth rates for 2012-2019 is [2.00, 3.27] ppm/yr with a largest one-year increase of 1.07 ppm/yr for 2015/16 caused by El Niño. Uncertainties are 0.38 [0.28, 0.44] ppm/yr limited by synoptic variability, including a 0.05 ppm/yr contribution from single-measurement precision. TCCON growth rates are linked to a UK Met Office forecast of a COVID-19 related reduction of -0.32 ppm yr-2 in 2020 for Mauna Loa. The separation of TCCON-measured growth-rates vs the reference forecast (without COVID-19) is discussed in terms of detection delay. A 0.6 [0.4, 0.7]-yr delay is caused by the impact of synoptic variability on XCO2, including a »1-month contribution from single-measurement precision. A hindrance for detection of the COVID-19 related growth-rate reduction in 2020 is the ±0.57 ppm/yr uncertainty for the forecasted reference case (without COVID-19). Assuming ongoing growth-rate reductions increasing year-on-year by -0.32 ppm yr-2 would allow a discrimination of TCCON measurements vs the unperturbed forecast and its uncertainty – with a 2.4 [2.2, 2.5]-yr delay. Using no forecast but the max-min range of the TCCON-observed growth rates for discrimination only leads to a factor »2 longer delay. Therefore, forecast uncertainties for annual growth rates must be reduced. This requires improved terrestrial ecosystem models and ocean observations to better quantify the land and ocean sinks dominating interannual variability. The paper highlights the results of our first published study based on 4 midlatitude TCCON sites and gives an outlook to our ongoing work including all TCCON sites. TCCON will be a valuable basis to monitor the Paris process in the years to come.

Reference:

Sussmann, R., and Rettinger, M.: Can We Measure a COVID-19-Related Slowdown in Atmospheric CO2 Growth? Sensitivity of Total Carbon Column Observations, Remote Sens., 12, 2387, https://doi.org/10.3390/rs12152387, 2020.
One-year long common view measurements with continuous gravimeters
Authors: Pereira Dos Santos Franck , Vermeulen Pierre , Bonvalot Sylvain , Gabalda Germinal , Le Moigne Nicolas , Champollion Cédric , Antoni-Micollier Laura , Merlet Sébastien
Published: March 2021

Since a few years, several laboratories, institutes or organizations through the world have acquired marketed quantum absolute gravimeters AQG developed by Muquans. Among their potentialities, these new generations of instruments are expected to complement the existing capabilities of long term monitoring of the Earth gravity field. A metrological evaluation of their performances for long-term measurements is thus a first step.

The LNE-SYRTE gravimetry laboratory in the suburb of Paris, has been designed to accommodate other gravimeters for metrological comparisons, tests and calibrations. Instruments of different classes operate in this well characterized laboratory: a laboratory-based absolute cold atom gravimeter (CAG) and a relative superconducting gravimeter iGrav. Both instruments allow for continuous measurements, Accuracy is guaranteed by the CAG and long-term stability by the iGrav.

We there have performed a more than one-year long measurement session with the initial version of the marketed quantum gravimeter AQG (AQG-A01).

An improved version of this AQG (AQG-B01) designed for outdoor measurement and recently acquired by RESIF (the French Seismologic and Geodetic Network) has been also implemented to close this session with a last month of simultaneous data recording involving all the instruments. Finally, we also performed supplementary accuracy tests, in particular to evaluate the Coriolis bias of the two AQG commercial sensors.

The talk will briefly present the different instruments to rapidly focus on the performances of the AQGs and results of the comparisons.
Late Mesozoic – Cenozoic evolution of the eastern Cyprus offshore
Authors: Bertone Nicolò , Bonini Lorenzo , Del Ben Anna , Brancatelli Giuseppe , Camerlenghi Angelo , Forlin Edy , Klaeschen Dirk , Pini Gian Andrea
Published: March 2021

The present‐day tectonic setting of the Eastern Mediterranean Sea results from a long deformation history, characterized by an alternation of extensional and contractional phases: from Mesozoic rifting to Late Cretaceous-present-day compression. This study focused on the tectonic reconstruction of the north-eastern side of the Mediterranean Sea, on a sector located between the Turkish coast and the northern Levantine Basin, using seismic reflection profiles. Previous studies dealt with the recent (Neogene) evolution because they did not have enough depth of investigation to recognize deeper reflections. We used vintage data such as MS and Strakhov surveys to analyze the deeper part of the area. We interpreted and depth-converted these seismic data, and we developed a sequential restoration to reconstruct the stratigraphic and structural evolution of the study area. 

In general, from north to south, we recognize the Cilicia Basin: a piggy-back basin bordered to the south by the offshore continuation of the Kyrenia Range. The Kyrenia Range is a positive flower structure generated during a transpressional phase because of the rotation of the Arabic plate. Southward, a secondary contractional system with an onlapping wedge is present in the area between the Kyrenia Range and another prominent ridge, i.e. the Larnaca Ridge. In the southern part, the same transpressional phase that generated the Kyrenia Range led to a positive inversion of an ancient extensional system, i.e. the Latakia Ridge. Beyond these positive flowers, the Levantine Basin is affected by extensional structures showing weak positive reactivation, including halokinetic features.

In summary, we found that the inherited extensional structures strongly impacted the following contractional ones affecting both their geometry and their kinematics.
Stratigraphic noise in isotope records on the East Antarctic Plateau; new insights from an array of firn profiles
Authors: Hirsch Nora , Zuhr Alexandra , Münch Thomas , Hörhold Maria , Freitag Johannes , Dallmayr Remi , Laepple Thomas
Published: March 2021

Stable oxygen isotopes from firn and ice cores provide valuable information on past climate variations, however, single profiles showed not to be representative for robust climate reconstructions. Stratigraphic noise, i.e. the irregular deposition and spatial redistribution and erosion of snow due to the influence of wind drift and the local topography, prevents a regular layering of the accumulating isotopic climate signal. It thus essentially impacts the utilization of high-resolution stable isotope records in low-accumulation areas.

Here, we assess the amount and structure of the stratigraphic noise at six different locations on the East Antarctic Plateau. The locations are sited along a traverse of ca. 83 km length and cover accumulation rates of 43 – 59 mm/a (Rotschky et al., 2004). At each location, we analysed five one-metre isotopic profiles with 10 m spacing between each other. A sequence of absolute snow heights was recorded at each sampling location. We further used the large-scale topography for this area derived from a digital elevation model by Helm et al. (2014). The isotopic profiles are used to quantify the signal-to-noise ratios, whereas accumulation rates, surface roughness and slope inclination can give insights on the environmental settings of the different locations and potential relationships to the stratigraphic noise.

We found signal-to-noise ratios between 0 and ~0.6 for the different locations with slightly higher values for locations on plateaus which exhibit a smaller surface roughness and higher accumulation rates. We were able to identify common isotopic peaks for the single profiles at only two locations, indicating strong changes of the local topography throughout the time of accumulation. A comparison of the mean profiles of each location with simulated profiles based on ERA5 temperatures and precipitation, resulted in correlations between 0.38 and 0.8. This confirms a reduction of stratigraphic noise for several locations, when averaging single profiles. We conclude that the correct drilling location for high-resolution firn and ice cores can already significantly improve the signal to noise ratio. However, a larger number of profiles is still necessary to minimise the contribution from stratigraphic noise in mean isotopic profiles and to achieve reliable climatic information from high-resolution firn cores on the East Antarctic Plateau.
Magmatic processes leading to the 1650 CE explosive eruption at the Kolumbo submarine volcano, Greece.
Authors: Mastroianni Filippo , Fantozzi Iacopo , Petrone Chiara Maria , Vougioukalakis Georgios E. , Braschi Eleonora , Francalanci Lorella
Published: March 2021

Kolumbo is the largest of twenty submarine volcanic cones, tectonically aligned in the transtentional Anydros basin, one of the most seismically active zones in the South Aegean Volcanic Arc, whose magmatism is related to the subduction of the African Plate beneath the Aegean microplate. Kolumbo explosively erupted in 1650 CE, causing the death of 70 people on Santorini, which is only 7 km SW of Kolumbo. Explorative cruises employing ROVs discovered a high temperature (220°C) hydrothermal field with CO2-rich discharges and accumulation of acidic water at the bottom of the crater (505 m b.s.l.), increasing the related hazard. A possible magma chamber was recognized below the crater at depth 9-6 km by seismic data [Dimitriadis et al. 2009]. Geochemical data [Klaver et al. 2016] suggest that Kolumbo have a different mantle source and storage system from Santorini. It is fundamental to understand the behaviour of this volcano, and how its storage and plumbing system works, to correctly assess risk for nearby islands.

We present petrographic, geochemical and isotopic data of samples collected during the cruises and by divers. Most samples represent the juvenile products of the 1650 CE activity, characterizing different magmas interacting before the eruption. They consist of white rhyolitic pumices with grey and black bands, also including basaltic-andesitic enclaves. Plagioclase, biotite, pyroxenes are the main mineral phases; olivine is found in the mafic enclaves. Minerals show quite complex zoning and a large compositional variability. Fresh lithic lavas were sampled; they also have amphibole and can be subdivided in three groups with distinctive petrographic textures that are well reflected in their different chemical compositions. They give information on the early history of the volcano and on how the rhyolitic magma could have been generated.

Our data suggest the presence of a complex storage system where the most evolved magma differentiated by assimilation and fractional crystallization, undergoing several inputs of mafic magmas. Early batches of new melts initially mixed with the resident ones, whereas later arrivals only mingled with the rhyolitic magma, thus possibly representing the final trigger of the eruption.
Socio-hydrological modelling to manage and mitigate hydrological droughts
Authors: Wendt Doris E , Bloomfield John P , Van Loon Anne F , Larsen Joshua R , Hannah David M
Published: March 2021

Managing water-human systems in times of water shortage and droughts is key to avoid overexploitation and reduce drought impacts. Drought policies are designed to structure water management response and avoid crisis management, aiming to sustain both environmental and anthropogenic water demand. However, the impact of drought policies on the hydrological cycle is rarely assessed. We developed a socio-hydrological model, simulating feedbacks between water availability and managed water use for 3 decades. Thereby, we aim to assess the impact of drought policies on both surface water and groundwater droughts. We tested this model in an idealised catchment driven by English climate data, representing English water resource management practices and drought policies. The model environment includes a surface water storage (reservoir), a range of hydrogeological conditions for the groundwater module, and an option to import surface water or groundwater that could all be used to satisfy anthropogenic and environmental water demand. Modelled scenarios represent four aspects of drought policies: 1) increased water supply, 2) restricted water use, 3) conjunctive water use, and 4) maintained environmental flow requirements that were evaluated in separate and combined scenarios. Results show that hydrological droughts are mitigated in scenarios applying conjunctive use, particularly in low groundwater storage systems. In high groundwater storage systems, maintaining environmental flows reduces hydrological droughts most, particularly for surface water droughts. Scenarios that gradually increase water supply or restrict water use have opposite impacts on droughts and these scenarios are in balance when combined according to the policies in the resources management plans. Most combined scenarios reduce the severity and occurrence of hydrological droughts, although the dependency on importing water increases, satisfying a third of the total anthropogenic water demand. The increased dependency on imported water shows the considerable pressure on water resources and the delicate balance of water-human systems during droughts that calls for short-term and long-term sustainability targets within drought policies.
Aeolus Calibration, Validation and Science Post-Launch Campaigns
Authors: Fehr Thorsten , Amiridis Vassilis  , von Bismarck Jonas , Bley Sebastian , Flamant Cyrille , Hertzog Albert , Lemmerz Christian , Močnik Griša , Parrinello Tommaso , Skofronick-Jackson Gail , Straume Anne Grete
Published: March 2021

ESA supported airborne and ground-based campaigns constitute an essential element in the development and operation of satellite missions, providing the opportunity to test novel observation technologies, acquire representative data for the development of the mission concepts, processors and use cases, as well as in their calibration and validation phases once in orbit.

For the Aeolus Doppler Wind Lidar satellite mission, ESA has implemented a campaign programme that started in 2007 and has continued beyond the launch of the mission on 22. August 2018. Building on the successful WindVal-I and –II campaigns with DLR’s A2D and 2µm Doppler Wind Lidar systems on-board the DLR Falcon aircraft, a number of validation campaigns have been successfully implemented: WindVal-III in November 2018, AVATAR-E in May 2019, and AVATAR-I in September 2019. In addition, ESA supported the CNES pre-Stratéole-2/TAPAPA campaign with eight stratospheric balloons having been launched from the Seychelles in November/December 2019 providing unique upper level wind data in the Tropics. The validation by stratospheric balloons has been extended in the frame of a collaboration with Loon LLC for a test case covering the months August and September 2019.

As the largest impact of the Aeolus observations is expected in the Tropics, and in particular over the Tropical oceans, ESA, in close collaboration with NASA and European partners, is currently implementing a Tropical campaign in July 2021.  With its base in Cape Verde the activity comprises both airborne and ground-based activities addressing the tropical winds and aerosol validation, as well as a wide range of science objectives. The location is unique as it allows the study of the Saharan Aerosol layer, African Easterly Waves and Jets, the Tropical Easterly Jet, as well as deep convection in ITCZ and tropical cyclogenesis, with a focus on the impact of Saharan dust on micro-physics in tropical cloud systems. The campaign builds on remote and in-situ observations from aircraft (DLR Falcon-20, the Safire Falcon-20, the NASA DC-8 and an Aerovizija/UNG light aircraft) and drone systems, as well as an extensive aerosol and cloud measurement programme with a range of lidar, radar and radiometer systems coordinated by NOA.

This paper will provide a summary of the Aeolus campaign activities, focussing on the completed and planned post launch campaigns.
Changes in patterns of extreme temperature distribution across different regions in India
Authors: Borah Angana , Bhatia Udit
Published: March 2021

Global studies of extreme temperature suggest that in recent times there has been an increase in frequency and intensity for hot temperature and decrease for cold temperatures  while a few others show an increase in both warm and cold extremes in the last decade of the twentieth century. Previous research on large scale climate projections show an amplified increase in the highest percentile of maxima and minima, with respect to the lowest percentiles of temperature extremes. The indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices (ETCCDMI) to analyse trends of extreme climate are pertinent to policy and decision making with regard to impact and adaptation studies. While literature is abundant with large scale evaluation of trends in extreme temperatures, there is a want of studies in the regional patterns and distribution of temperature extremes in India. Although India is widely known as a tropical country, the diversities found in the topography of the regions from north to south and east to west, renders microclimate unique to each region leading to disparate inter-annual temperature ranges across the country. So, it is important to explore how regional trends in the different climatic zones of the Indian subcontinent correspond with each other in view of its unique climatic regimes. A comprehensive analysis of temperature extremes in the urban agglomerates and their suburban and rural counterparts is relatively unexplored for India. The results offer insights on the change in the percentile based indices recommended by the IPCC as well as summer and winter maximas and minimas for the entire India over the last several decades. The frequency and intensity of extreme temperatures characterised by number of days less than 10th percentile and more than 90th percentile, and minimum annual minimum temperature and maximum annual maximum temperature respectively, of the distribution over the last six decades have been assessed. The findings of this study suggests that warmer extremes follow an increasing trend, while the colder extremes exhibit no significant trend. However, the trends appear to be spatially coherent irrespective of the extent of urbanization.   Additionally, change in maximum and minimum percentiles of summer and winter temperatures are assessed between the first half of the last century and  the later half of the last century, for the entire country. It was found that change in highest percentiles in both summer and winter minima is more pronounced than lowest percentiles, while increase in highest percentile is more amplified for summer and winter maxima. 

 
The effect of COVID-19 restrictions of human activities on atmospheric chemical cocktail, new particle formation  and air quality in in Eastern and Northern China
Authors: Kulmala Markku , Yan Chao , Dada Lubna , Bianchi Federico , Kokkonen Tom , Jiang Jingkun ,   Aerosol and Haze Laboratory Team
Published: March 2021

The pandemic of SARS-CoV-2 has led to a substantial reduction in anthropogenic activities globally. This is particularly true for traffic, which was reduced by 40-80 % in Eastern and Northern China. The imposed lockdown provides a unique opportunity to investigate the direct and indirect effects of anthropogenic activities (particularly traffic) on atmospheric new particle formation, atmospheric chemical cocktail and haze formation in polluted urban environments in the case when the emissions were substantially lower. Here, we utilize comprehensive, long term ground-based and satellite observations to investigate changes in the atmospheric composition and connect them with a continental scale gas-to-particle conversion producing both fresh particles and new aerosol mass.  We show  that despite the reductions in emissions, both new particle formation (NPF) and haze events still occur. The observational evidence confirms that the main NPF mechanism remains similar because of non-linear response of NPF and growth to local and regional vehicle emission reductions. Furthermore we are able follow the growth from NPF to haze and show, in the case study, that regional NPF makes a dominating contribution to the haze.
Interreg Atlantic Area AGEO Project – Explaining natural hazards and the role of citizen observatories through storytelling
Authors: Ortega Rodriguez Ariadna , Carrilho Gomes Rui , Correia Vitor , Pinto Cláudia , Bodó Balazs , Cseko Adrienn
Published: March 2021

The Platform for Atlantic Geohazard Risk Management (AGEO) is a project co-financed under the Interreg Programme for the Atlantic Area that aims to launch five Citizens’ Observatory pilots on geohazards according to regional priorities:

Citizens’ observatory on rockfalls and rockfall-triggers in the Canary Islands, Spain

Citizens’ observatory on rockfalls and rockfall-triggers in Giants' Causeway and Carrick-a-rede, Northern Ireland

Multihazard Citizens Observatory in Lisbon, Portugal

Citizens’ observatory of slope instability monitoring in Madeira island, Portugal

Citizens’ observatory of vulnerability to coastal Risks in Brittany, france

These pilots will demonstrate how citizens’ involvement in geohazard risks prevention can strengthen regional and national risk management systems. The consortium is led by the Instituto Superior Técnico (Portugal) andcounts with several other partners from Portugal, Spain, France, Ireland and the United Kingdom.

Experiences gained during the implementation of the Citizens’ Observatory pilots will be used to formulate recommendations for the creation of future observatories in response to the widest range of hazards (both natural and human-induced) faced in the Atlantic region. Engaging citizens in Citizens Observatories requires the development of outreach strategies seeking to understand expectations and develop attitudes, behaviours and competencies relevant for the aims and activities of the observatories.

The AGEO Consortium identified and targeted relevant stakeholders using Mendelow’s (1991) power-interest matrix, and developed perceptual maps of stakeholders, adapted for each of the five Citizens’ Observatory pilots. This approach was the basis for the development of tailored value propositions formulated to raise awareness on geohazards  and mobilize citizens participation.

AGEO is also using storytelling to inspire the general public to action and emotionally implicate non-specialised audiences. This approach is being used to educate children at school age and to reach their parents (in the pilot regions).

 

 

Mendelow, A. L., 1991. Environmental Scanning: The Impact of the Stakeholder Concept. Proceedings from the Second International Conference on Information Systems 407-418. Cambridge, MA.https://aisel.aisnet.org/icis1981/20/
Aircraft observations of NO2 and NH3 over selected locations in Germany
Authors: Clarisse Lieven , Tack Frederik , Ruhtz Thomas , Merlaud Alexis , Van Damme Martin , Schuettemeyer Dirk , Coheur Pierre , Van Roozendael Michel
Published: March 2021

Anthropogenic atmospheric emissions of the reactive nitrogen components nitrogen dioxide (NO2) and ammonia (NH3) have majorly altered the global nitrogen cycle in the past 100 years, with devastating consequences to biodiversity, soil, water and air quality. Thanks to effective legislation, NO2 emissions are declining worldwide. Unfortunately, this is not the case for NH3 for which a recent study reports yearly increases of around 2% in Europe and the U.S. and up to 6% in East Asia. 

Both species are currently actively monitored with several satellite sounders, which provide daily global measurements. Yet, the spatial resolution of current sounders is inadequate for resolving the highly heterogonous spatial distributions of both species. This is particularly the case for point source emitters, for which satellites are currently only able to quantify the largest and most isolated ones. To fill the important gap in the monitoring landscape, a satellite called Nitrosat has been proposed in answer to ESA’s Earth Explorer call.  The satellite would allow making simultaneous measurements of NO2 and NH3 at a spatial resolution of 500 meter. In support to the Nitrosat proposal, ESA has funded a project called NITRO-CAM (Nitrogen cycle airborne measurements), which aims at mapping simultaneously NO2 and NH3 in the Greater Berlin area using aircraft measurements. It is the results of this campaign that are presented here. These can be seen as proof-of-concept for Nitrosat, but are also interesting in their own right. A larger focus is given to NH3, for which the presented measurements are the first of their kind.

Campaign flights were performed in the surroundings of Berlin in the autumn of 2020. A follow-up campaign is foreseen in early spring. Measurements are performed with BIRA’s UV-VIS spectrometer newly-developed SWING instrument for NO2 and TELOPS thermal infrared HYPER-CAM for NH3. Surveying gapless areas of at least 10 by 10 km, the measurements enable capturing the emissions of both point and area sources, and are suitable for degrading at various hypothetical satellite instrument footprints.  For NO2 specifically, Berlin and nearby power plants are targeted, while for NH3 the Piesteritz fertilizer factory is targeted, as well as rural areas in the surroundings of Berlin.   
A terrestrial temperature peak in the first millennia after the Cretaceous-Paleogene Boundary 
Authors: Price Gregory , Dearing Crampton-Flood Emily , Jerrett Rhodri , Lengger Sabine , van Dongen Bart , Naafs David , Pancost Richard , Lempotesis-Davies Aris , McCormack Paul
Published: March 2021

The Cretaceous-Paleogene (K-Pg) boundary marks one of the five major mass extinctions of the Phanerozoic. A bolide impact and flood basalt volcanism compete as triggers for the extinction, but their relative roles remain contentious. This is in part related to a paucity of robust measurements of temperature change at millennial time scales across the K-Pg boundary. Using the distribution of branched tetraether lipids in samples collected from coals (fossil peats), we present the initial findings of an ongoing study attempting to reconstruct temperatures across North America in the latest Cretaceous to earliest Paleogene. The glycerol dialkyl glycerol tetraether (brGDGTs) palaeotemperature proxy – which has been successfully applied to temperature reconstructions in the Pleistocene and Holocene – is being applied to a succession of fossil peats (lignites) that span the K-Pg boundary at ten sites from Colorado in the south to the North West Territories in the north. The Iridium anomaly that is synonymous with bolide impact at the K-Pg boundary can be used as a datum to correlate the coals. Data derived from coals deposited at a latitude of ~55 °N in Saskatchewan (Canada), are interpreted to reveal millennial-scale records of terrestrial mean annual air temperature (MAAT) for an interval spanning the latest Maastrichtian and earliest Paleogene. The MAAT record peaks at 28 °C ~1 ka (+ 4 ka/- 0.3 ka) after the K-Pg boundary, and subsequently recovers to pre-event values in the subsequent ~ 5 ka (+30 ka/-2 ka). Our unique record is consistent with an abrupt increase in atmospheric CO2 that has been widely documented at this time. 
On Magnetic Helicity and Field-Aligned Currents in the Polar Ionosphere
Authors: De Michelis Paola , Consolini Giuseppe , Alberti Tommaso , Carbone Vincenzo , Tozzi Roberta , Coco Igino , Giannattasio Fabio
Published: March 2021

Magnetic helicity, which is a measure of twist and linkage of magnetic field lines, is a useful quantity to investigate some processes occurring in space plasmas. In particular, there is a strong link between magnetic helicity, magnetic flux structures, turbulence and dissipation. We investigate the connection between the reduced magnetic helicity and the structure of field-aligned currents in the high-latitude ionosphere using high resolution (50 Hz) magnetic data collected on board the ESA Swarm constellation. We show the existence of a clear link between the multiscale coarse-grained structure of reduced magnetic helicity and the field-aligned currents. This finding strongly supports the idea that turbulence processes might be at the origin of the observed small-scale current structures. A discussion of the relevance of our results in the framework of the filamentary nature of the field-aligned current is also presented.

This work is supported by Italian PNRA under contract PNRA18_00289-A “Space weather in Polar Ionosphere: the Role of Turbulence ".
Rising To The Challenge: Addressing climate literacy in Ireland through the lens of student rights
Authors: Neenan Emer Emily
Published: March 2021

A recent geoscience education project, undertaken in Irish secondary schools using a children's rights based methodology that incorporated student voice in the design, implementation, and analysis, began with a focus on "Earth Science" but ended, through the influence of the student co-researchers, with a focus on climate literacy. Teenagers have seen the writing on the wall, as sea levels and global temperatures rise, and traditional career paths and global superpowers fall. 

Following on from the aforementioned project, an international comparative study currently ongoing seeks to establish global best practice in geoscience education and climate literacy, with the aim of facilitating improvement in the Irish context. Research suggests Irish school students are eager to learn about the Earth, but are frustrated by classes on climate change that are not actionable and do not address the systemic causes of the climate catastrophe. There is an appetite among teenagers and young people to learn more, but simply adding more classes or more class time isn't sufficient, the classes must be appropriately challenging, honest, and action-focused. This ongoing research seeks to provide guidance and tools to achieve that in Irish formal and informal education. 

Thus, in this presentation, the findings of a recent geoscience and climate change education project will be discussed in the context of how the expressed needs and opinions of the participating students have impacted the ongoing international comparative study seeking to improve Ireland's geoscience and climate literacy.
Effect of sediment-organism interactions on hyporheic exchange in streams: role of sediment reworking time
Authors: Shrivastava Shivansh , Stewardson Michael , Arora Meenakshi
Published: March 2021

In-stream faunal organisms constantly interact with their habitat to modify its physical and hydraulic properties. However, little is known about how sediment-organism interactions could modify the hyporheic exchange. Previous experimental work investigating the effects of the activities of faunal organisms on exchange across the sediment-water interface has been largely conducted in small mesocosms or infiltration columns that do not represent the lotic environment adequately. Therefore, the experimental findings from these studies may not be transferable to flowing water environments (e.g., streams). Our previous experimental work demonstrated that sediment reworking by macroinvertebrates could significantly alter the hyporheic flux, mean residence times, and depth of exchange in streambeds. In this work, we explore how sediment-organism contact time influence the effect of the activities of model organisms, Lumbriculus variegatus, on the hyporheic flow regime. We conduct laboratory experiments in re-circulating flumes subject to different sediment reworking times (5 and 10 days). The hyporheic flow characteristics in these flumes were studied by conducting dye tracer tests after the bed sediments were reworked. Deposition of fecal pellets and holes/burrows dug by sample organisms were visible at the bed surface in both the experimental flumes. The flume reworked for a longer time exhibited higher hyporheic flux, longer median/mean residence times, and deeper depth of solute penetration compared to the flume reworked for a shorter period. The modification of hyporheic flow regime to different degrees depending on the sediment reworking times has direct relevance to the biogeochemistry in hyporheic zones, and thus on the overall quality of surface and sub-surface waters. We advocate that more intensive laboratory experiments and field investigations must be conducted to support the findings from our study and advance our understanding of the role of the activities of faunal organisms on fluvial ecosystem functioning.
Meandering channels over ice: Cooler and unique?
Authors: Fernández Roberto
Published: March 2021

Experimental work on small-scale meltwater meandering channels over ice and field observations have identified similarities and differences between their planform morphologies and those of meandering channels in other media (e.g. alluvial, bedrock). Qualitatively and quantitatively, planform characteristics, including sinuosity, wavelength-to-width ratios, coefficient of skewness and fatness, suggest that most meandering channels behave in certain ways and within certain ranges. However, what makes meltwater meandering channels over ice unique? In this contribution, I highlight the different aspects that set meltwater meandering channels over ice apart from meandering channels in other media and share ongoing work focusing in their planform morphologies, curvature signals, and cross section geometry.
Can a model weighting scheme be used to obtain skillful, reliable and  seamless climate information for the next 1-40 years?
Authors: Weisheimer Antje , Befort Daniel J. , Brunner Lukas , Borchert Leonard F. , Ballinger Andrew P. , O'Reilly Christopher H. , Hegerl Gabi , Mignot Juliette
Published: March 2021

Skillful, reliable and seamless climate information for the next 1-40 years is crucial for policy- and other decision makers to develop suitable planning strategies. This poses a challenge for the scientific community, which is split up into the prediction community (developing initialized predictions up to multi-annual time scales, e.g. 10 years), and the climate projection community (providing long-term projections). As predictions are initialized with the observed climate state at the start of the integration, they are often more skillful for lead times of a few years (depending on variable and region) compared to uninitialized climate projections, which can provide information beyond 10 years. Thus, most useful climate information for the next 1-40 years would likely need to draw upon information from both sources. However, temporal merging from different sources is challenging, e.g., it can lead to discontinuities in the central estimates at the respective transition points, which pose problems for interpretation and communication alike.

The aim of this study is to explore if skillful and seamless climate information can be provided by applying a model weighting scheme to initialized decadal predictions and projections. The model specific weights are based on the respective past model performance compared to observations. Whereas for climate projections each model is assigned a single weight, for initialized decadal predictions these weights are calculated for each forecast year separately. Here, we apply the weighting technique to CMIP6 decadal predictions and climate projections from 8 different models. 