bluuebunny/crossref_metadata_2025 huggingface dataset:
The international flood damage database HOWAS 21
Authors: Kreibich Heidi , Krahn Astrid , Schröter Kai
Published: March 2021

The Flood Damage Database HOWAS 21 (https://doi.org/10.1594/GFZ.SDDB.HOWAS21) contains object-specific flood damage data resulting from fluvial, pluvial and groundwater flooding. The 8329 datasets (as at January 2021) incorporate various variables of flood hazard, exposure, vulnerability and direct tangible damage at properties from several economic sectors. The sectors comprise private households, commercial and industrial sector, agricultural and forested land, public thoroughfare (including roads and transport infrastructure) and watercourses and hydraulic structures. Although it currently almost exclusively contains datasets from Germany, it is still unique in respect to amount of data and detail of contained variables. HOWAS 21 mainly supports forensic flood analysis and the derivation of flood damage models. HOWAS 21 was first developed for Germany in 2007 but has recently been enhanced to an international flood damage database. This presentation shows the recent advancements of HOWAS 21 and highlights exemplary the use of HOWAS 21 flood damage data. HOWAS 21 is available at https://howas21.gfz-potsdam.de/howas21/

The use of HOWAS 21 follows a community-based concept, i.e. institutions that provide a defined amount and quality of data to HOWAS 21 get full access to the entire database. Thus, HOWAS 21 depends on the cooperation and commitment of the (scientific) community. The empirical flood damage database can only continuously grow, and as such increase its value for the whole community, if collected flood damage data are provided to HOWAS 21. Therefore, if flood damage data are or become available, we expressly encourage data owners to include them in HOWAS 21 for their own benefit and for the benefit of the whole community.
What if the best option for managing burnt forest areas was not managing them at all? A modelling approach to evaluate different post-fire management scenarios 
Authors: Basso Marta , Martins Martinho , Serpa Dalila , Keizer Jacob , Vieira Diana
Published: March 2021

Scars left by wildfires are easily noticeable in the Mediterranean landscape, turning these events a major issue for forest management. Like any wound, even those left by fires must be treated to properly regenerate.

In a burned area the vegetation cover is often destroyed by the fire, leaving the soil unprotected and vulnerable to erosion. The alterations of soil properties induced by fires lead to an increase in surface runoff, promoting the detachment of sediments and consequently endangering the water quality of downstream aquatic systems. If left unmanaged, the spontaneous regeneration of vegetation will eventually cover the affected area, restoring its natural hydrological cycle. After a wildfire, in Portugal, following an economical based perspective, the burned areas are normally reforested with selected plants species, namely Eucalypt and Maritime Pine, not infrequently by resorting to the implementation of bench terraces.

To define the best management strategy to adopt after a fire, the scientific community is continuously assessing the effects of these forestry practices on soils and the downstream water bodies. In this study, the Soil and Water Assessment Tool (SWAT) was used to simulate three different post-fire land management scenarios for a small catchment (21.9 ha) in central Portugal. The choice of this basin relates to the implementation of terraces to create a eucalyptus forest production area, 6 months after a fire burned the catchment completely. The model was calibrated for streamflow and water quality at the catchment outlet, both for the short post-fire period and the following eucalyptus cycle. In this study two post-fire scenarios were created, one with the recovery of the vegetation, and another in which a highly effective erosion mitigation measure (mulching) was applied to the high and moderate fire severity burned areas. The third scenario corresponded to the implementation of the terraces and the actual eucalyptus cycle.

Both the mulch application and the eucalyptus cycle scenario showed an important reduction in soil loss and sediment transport when compared with the post-fire spontaneous recovery scenario. A smaller reduction in the total runoff, as well as a negligible change in total flow, was found in the mulching scenario when compared with the spontaneous recovery one. Despite the eucalyptus cycle presented the highest flow discharge for the overall period, it presents smaller discharge peaks when compared with the two post-fire management scenarios.
Quantifying methane emissions from fossil fuel sources using a Bayesian inverse model and observations of ethane with an uncertain emissions ratio
Authors: Ramsden Alice , Ganesan Anita , Western Luke , Manning Alistair , Rigby Matthew , Say Daniel , Wisher Adam , Arnold Tim , Rennick Chris , Levy Peter , Young Dickon , O'Doherty Simon
Published: March 2021

Methane is an important greenhouse gas with a range of anthropogenic sources, including livestock farming and fossil fuel production. It is important that methane emissions can be correctly attributed to their source, to aid climate change policy and emissions mitigation efforts. For source attribution, many ‘top-down’ models of atmospheric methane use spatial maps of sources from emissions inventory data coupled with an atmospheric transport model. However, this can cause difficulties if sources are co-located or if there is uncertainty in the sources’ spatial distributions.

To help with this issue and reduce overall uncertainty in estimates of methane emissions, recent methods have used observations of a secondary trace gas and its correlation with methane to infer methane emissions from a target sector. Most previous work has assumed a fixed emissions ratio between the two gases, which often does not reflect the true range of possible emission ratios. In this work, measurements of atmospheric ethane and its emissions ratio relative to methane are used to infer emissions of methane from fossil fuel sources. Instead of assuming a fixed emission ratio, our method allows for uncertainty in the emission ratio to be statistically propagated through the inverse model and incorporated into the sectoral estimates of methane emissions. We further demonstrate the inaccuracies that can result in an assessment of fossil fuel methane emissions if this uncertainty is not considered.

We present this novel method for modelling sectoral methane emissions with examples from a synthetic data experiment and give results from a case study of UK methane emissions. Methane and ethane observations from a tall tower network across the UK were used with this model to produce monthly estimates of UK fossil fuel methane emissions with improved uncertainty characterisation.
Identification of a fault zone beneath Moxa observatory (Central Germany): evidence from combining logging, rock physical measurements, and geophysical profiling
Authors: Kasburg Valentin , Valchev Todor , Goepel Andreas , Schwarze Cornelius Octavian , Kukowski Nina
Published: March 2021

Geophysical observatories aim to decipher natural processes taking place in very different parts of the Earth’s interior by recording long time series of various signals related to these processes. As such signals, e.g. fluctuations of deformation or temperature, may be very small, complementary information e.g. from climate stations and very good knowledge of geological structures in the vicinity of an observatory is indispensable. Moxa Geodynamic Observatory, belonging to Jena university is located in a remote area in the Palaeozoic Thuringian Slate Mountains, which however, is characterized by complex subsurface structures with regard to fluid transport and hydrology, including a suspected fault beneath the observatory.

Information about the subsurface beneath the observatory and its geological structures is available from various near-surface geophysical surveys including numerous geo-electrical profiles. These were used to undertake 3D resistivity tomography.

Here we use rock physical measurements, including thermal conductivity, permeability and seismic velocities, on core material from the research drill hole next to the observatory building to characterise the silty greywackes. This data set is complemented by the evaluation of logging data and inspection of long-term temperature data obtained from records of an optical fibre deployed in the borehole to characterize the drilled rocks and identify sections which may favour ground water transport. We also identified fissures from the acoustic televiewer and thus found several depth intervals which could represent a fault zone. Finally we used this information and the results of the resistivity tomography to propose a structural model for the subsurface including the position and type of the suspected fault zone.
Study on the complexity reduction of the input data for 3D numerical modeling of the hydrodynamics and sediment transport in a Brazilian reservoir  
Authors: Gonzalez Wendy , Mees Delfes Varela Diogo , Seidel Frank
Published: March 2021

The importance of water reservoirs has been increasing with population growth and the need of water supply. Understanding the environmental processes in these water bodies is essential for the correct management performed by stakeholders. In this context, numerical models appear as a great tool for simulating hydrodynamics and sediment related processes and presenting them in way easy to understand. However, a wide range of data is required as input for a good performance of these models and its quality have a direct influence on the simulations results. Long term high resolution input data is the ideal case for simulations, but in developing countries this is usually not the case due to the absence of measured or simulated data to be used as input. The main objective of this research is to understand how the reduction of input data resolution and/or use of wrong datasets may influence final results of the processes taking place in reservoirs regarding the hydrodynamics, water temperature and sedimentation. Passaúna reservoir located in Curitiba, Brazil, is used as a study case with high resolution measured and simulated datasets which will be implemented as input data for numerical simulations using Delft3D. For the simulation of the horizontal velocities and the water temperature, parameters related to heat flux calculations showed the strongest influences on the results. A specific important parameter was the secchi depth, which is a single value used as input data and shows great differences for the reproduction of periods with mixed or stratified water column. On the other hand, sediment simulations showed sensitivity to the main river flow discharge temporal resolution and its corresponding sediment concentrations. Reanalysis data used as heat flux parameters and wind presented great differences from the use of measured datasets, but in cases where measured data is not available, this source may be the best choice for users.
How does aerosol forcing drive a strengthening of the AMOC in CMIP6 historical simulations?
Authors: Robson Jon , Menary Matthew , Gregory Jonathan , Jones Colin , Sinha Bablu , Stevens David , Sutton Rowan , Wilcox Laura
Published: March 2021

Previous work has shown that anthropogenic aerosol emissions drive a strengthening in the Atlantic Meridional Overturning Circulation (AMOC) in CMIP6 historical simulations over ~1850-1985. However, the mechanisms driving the increase are not fully understood. Previously, forced AMOC changes have been linked to changes in surface heat fluxes, changes in salinity, and interhemispheric energy imbalances. Here we will show that across CMIP6 historical simulations there is a strong correlation between ocean heat loss from the subpolar North Atlantic and the forced change in the AMOC. Furthermore, the model spread in the surface heat flux change explains the spread of the AMOC response and is correlated with the strength of the models’ aerosol forcing.  However, the AMOC change is not strongly related to changes in downwelling surface shortwave radiation over the North Atlantic, showing that anthropogenic aerosols do not drive AMOC change through changes in the local surface radiation budget. Rather, by separating the models into those with ‘strong’ and ‘weak’ aerosol forcing, we show that aerosols appear to predominantly imprint their impact on the AMOC through changes in surface air temperature over the Northern Hemisphere and the consequent impact on latent and sensible heat flux. This thermodynamic driver (i.e. more heat loss from the North Atlantic) is enhanced both by the increase in the AMOC itself, which acts as a positive feedback, and by a response in atmospheric circulation. 
A tool for evaluation of target area homogeneity at ecosystem stations employing eddy covariance method
Authors: Šigut Ladislav , Wutzler Thomas , El-Madany Tarek , Fischer Milan , Migliavacca Mirco
Published: March 2021

Our understanding of the carbon and water cycle was greatly improved through application of eddy covariance measurements in recent decades. Though powerful, this micrometeorological approach relies on a number of assumptions that can be affected by a selection of station location. Most importantly, terrain of the target area should be flat, target area should be homogeneous and adequate air mixing should be achieved. Although possible shortcomings can be reduced by careful site inspection before tower installation (flat terrain) or can be corrected for during data post-processing (filtering of periods with low mixing), preliminary assessment of target area homogeneity is difficult as well as correction of its impacts afterwards. The influence of such inhomogeneities can lead to a bias in the flux annual sums but also a bias in their relationships with environmental variables. Certain solutions were already proposed, but target area homogeneity was so far assessed only at a few selected sites. Here we aim to provide a suit of software tools that build on the existing software packages (REddyProc, Flux Footprint Prediction, openair, openeddy) and allow easy diagnosis of the situation at the given ecosystem station. We plan to provide directional analyses of variables of interest. This will allow to identify the wind sectors that show large deviations from the mean value of the whole target area. In a further step, we plan to combine footprint modeling with CO2 and energy flux measurements and thus provide attribution of mean (weighted) fluxes to their source area. Based on the differences with the directional analyses we will assess whether the higher computational expenses of footprint modeling are justified and bring additional information. Finally, we plan to separate the target area to a limited amount of wind sectors and attempt separate gap-filling and flux partitioning for areas identified by preceding homogeneity evaluation. The limitations and feasibility of this approach will be assessed.

This work was supported by the Ministry of Education, Youth and Sports of CR within Mobility CzechGlobe2 (CZ.02.2.69/0.0/0.0/18_053/0016924).
Changes on atmospheric electric field and PM 2.5 during the COVID-19 measures at Xanthi on 2020 compared to the 2019 measurements and depending on the circulation weather types
Authors: Karagioras Athanasios , Nita Andrei , Stavroulas Iasonas
Published: March 2021

We present here the results of a study on the changes of PM 2.5 and atmospheric electric field (Potential Gradient, PG) during COVID-19 measures implemented at Xanthi in comparison with the 2019 measurements according to 10 classes of circulation weather types (CWT). There are two study periods. The first period was from February to May of both 2019 (no lockdown measures were implemented) and 2020 (under lockdown), and the second period was from September to December of both 2019 (no lockdown) and 2020 (lockdown). For both study periods of 2020, Xanthi was subjected to additional measures, such as curfew. Specifically, from 01/04/2020 to 27/04/2020 from 20:00 to 08:00 and from 13/11/2020 to 31/12/2020 from 21:00 to 05:00. These periods were selected according the two lockdown periods of 2020 at Xanthi and the same periods were selected for the previous year. PM 2.5 was measured in two different locations, one in the city center of Xanthi and the other is located at a semirural location approximately 2 kilometers from the city center, where also PG was measured. We present results in comparison with mean PM 2.5 and mean PG per circulation weather type on no lockdown and lockdown periods of 2019 and 2020 respectively, at Xanthi. There were changes on mean PM 2.5 and mean PG per circulation weather type between the two years. A moderate decrease of PM 2.5 per CWT between the two periods of lockdown on 2020 due to COVID-19 measures and the same periods for 2019 is observed when there was neither lockdown nor curfew. Fluctuations and a variability on mean PG per CWT are also observed between the two years. We acknowledge support of this work by the project “PANhellenic infrastructure for Atmospheric Composition and climatE change” (MIS 5021516) which is implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund).
Identifying the regional impact of deep thermogenic gas on aquifers in Alberta, Canada by  comparing multilayered isoscape maps of domestic water wells and fugitive gases from energy wells
Authors: Gonzalez Arismendi Gabriela , Muehlenbachs Karlis
Published: March 2021

The origin and distribution of unwanted thermogenic gas in aquifers and domestic water wells in petroliferous basins are of continuing concern. Most published studies to date consider only a few water wells with little or no information on fugitive gases from nearby energy wells.   We mapped δ13C of  hydrocarbons in 1,124  domestic water wells and fugitive gases (many thousands) from energy wells of Alberta, Canada.  About 90% of the water wells that exsolve hydrocarbons produce methane derived locally by microbes. The δ13C of these biogenic methanes vary regionally and follows topography,  suggesting in situ generation of methane within a flowing aquifer perhaps following a Rayleigh constrained generation process. Some domestic water wells have free thermogenic butanes, propane and ethanes indicating the impact of thermogenic gas on the aquifer.  The δ13C of these thermogenic sourced gases impacting domestic water wells matches those of nearby energy wells indicating their failure as the ultimate source of thermogenic gas in domestic water wells.  The impacted water wells are geographically grouped. Our regional mapping of hydrocarbon gases in domestic water wells has identified specific, kilometre scale regions needing detailed hydrogeological and geochemical investigation.
How effective is Disaster Risk Reduction education? A longitudinal study of secondary school students in Dominica.
Authors: Parham Martin
Published: March 2021

Priority 3 of the Hyogo Framework for Action (HFA) (2005-2015) explicitly outlined the role of education to improve Disaster Risk Reduction (DRR). By 2013 the deadline to integrate DRR into school curricula had disappeared and when the Sendai Framework for Action (SFA) (2015-2030) was published it merely sought to ‘reduce losses from disaster risk’. This reduction in educational emphasis may be a consequence of difficulty to establish DRR effectively into school curricula. Despite this, UNESCO outlined a guide for effective approaches to DRR education (Kagawa and Selby, 2012).  This study presents results from a longitudinal study of secondary school students in Dominica, Caribbean, assessing the impact of three UNESCO educational approaches; interactive, surrogate and field-based learning.  These educational sessions occurred between 2016-2018 during a time where the population were subject to natural hazards, most notably Hurricane Maria in 2017.

This study uses the Pictorial Representation of Individual Self Measure (PRISM) to assess change in student perception of multiple hazards before and after educational sessions, as a measure of effectiveness.  The educational sessions were designed based on recommendations from past studies and through collaboration with local DRR professionals (aid agencies, government and local experts) and schoolteachers, to increase relevance to the local community.  Relevant pedagogic theories were integrated to encourage student engagement. 

All educational approaches were shown to have impact, though the greatest change in perception was caused by field-based learning. These sessions caused a greater change in student perception towards lower frequency, higher magnitude geophysical hazards. Some educational approaches, while considered ‘engaging’ did not have a clear DRR message which should act as a warning to the DRR community. This study highlighted the need for educational approaches to incorporate variety, participation, and adopt local relevance.  We highlight the need for improved integration between geoscience and educational professionals to improve DRR education. Further work also needs to be undertaken to understand the relationship between effective educational approaches for DRR and resourcing.
Dust Grain Detection by Solar Orbiter, Parker Solar Probe, and Magnetospheric Multiscale (MMS) Mission — Similarities and Differences
Authors: Vaverka Jakub , Pavlů Jiří , Nouzák Libor , Kočiščák Samuel , Šafránková Jana , Němeček Zdeněk , Píša David , Souček Jan , Zaslavsky Arnaud , Mann Ingrid , Maksimovic Milan , Bale Stuart , Linqvist Per-Arne
Published: March 2021

The dust impact detection by electric field instruments is already a well-established technique. On the other hand, not all aspects of signal generation by dust impacts and its consequent detection are completely understood and explained. It has been shown that the design and configuration (monopole/dipole) of the electric field antennas/probes are very important for dust impact detection and understanding of the measured signal. Therefore, it is not straightforward to compare detected signals by various spacecraft. Most of space missions use at the same time either monopole or dipole antenna configuration. However, the MMS simultaneous monopole and dipole measurements provide us with interesting information about dust impact signals. We have analyzed individual electric field waveforms of dust impacts detected by Solar Orbiter, Parker Solar Probe, and MMS to understand similarities and differences of dust detection by various spacecraft with different antenna designs and configurations. This understanding will allow us to reliably compare obtained dust fluxes among individual missions.  
Stratospheric OClO observed with ground-based DOAS over Kiruna in the Arctic winters 1996/1997 – 2019/2020
Authors: Gu Myojeong , Enell Carl-Fredrik , Pukite Janis , Platt Ulrich , Raffalski Uwe , Wagner Thomas
Published: March 2021

Recent research on stratospheric ozone indicates signs of ozone recovery, but on the other hand, ozone recovery is also expected to be delayed by many aspects (e.g climate change). Therefore, it is important to monitor continuously stratospheric trace gases to predict the future evolution of the Arctic ozone and other trace gases which are involved in the ozone depletion chemistry. OClO is well known as an indicator of the stratospheric chlorine activation and can be measured using remote sensing techniques.

In this study, we present long-term measurements of OClO slant column densities at Kiruna, Sweden (67.84°N, 20.41°E) which were obtained from the ground-based zenith sky DOAS instruments since 1997. The measurement site is located north of the polar circle in which the variability of the OClO abundance depends on the state of stratospheric chlorine activation but also whether the polar vortex is located above the measurement site.

The aim of this study is to give an overview of the measured stratospheric OClO abundance for 19 years, and to investigate the dominant parameters affecting ozone and OClO during periods of stratospheric chlorine activation. One particular focus is on the parameters which trigger the activation and de-activation at the beginning and the end of the polar winter.

To do so, we compare the general dependencies of OClO on other trace gases and meteorological conditions.
Effects of turbulent fluctuations on phase partitioning in adiabatic mixed-phase cloud parcels
Authors: Gomes Albuquerque Daniel , Coelho Abade Gustavo , Pawłowska Hanna
Published: March 2021

Several microphysical processes determine phase partitioning between ice and liquid water in a mixed-phase cloud. Here we investigate the collective growth of ice particles and liquid droplets affected by turbulent fluctuations in temperature and water vapor fields. All cloud particles, including inactivated nuclei (both CCN and IN), are described by Lagrangian super-particles. To account for local variability in the turbulent cloud environment we apply a Lagrangian microphysical scheme, where temperature and vapor mixing ratio are stochastic attributes attached to each super-particle. In addition, a simple linear relaxation scheme models turbulent mixing of the scalar fields probed by each super-particle. The limit of a locally homogeneous growth environment corresponds to an infinitely short turbulent mixing timescale. The impact of our Lagrangian microphysical scheme on phase partitioning is tested in adiabatic cloud parcel simulations. Results are confronted with idealized reference simulations that use bulk microphysics based on an assumed (temperature-dependent) phase partitioning function. Our study suggests that accounting for local variability in a turbulent cloud is important for reproducing steady-state mixed-phase conditions.
A Surrogate-Based Optimization Approach for Sustainable Drainage Design in Large Urban Areas
Authors: Seyedashraf Omid , Bottacin-Busolin Andrea , Harou Julien J.
Published: March 2021

The design of conventional and sustainable urban drainage systems is a complex task that requires consideration of several design objectives and decision variables. Simulation-based optimization models allow exploring the decision space and identify design options that best meet the design criteria. However, existing approaches generally require simulation of the system hydraulics for each function evaluation, which leads to prohibitive computational cost when applied to large drainage networks.

In this work, a disaggregation-emulation approach is proposed which allows sequential optimization of multiple sub-catchments in an urban area without having to simulate the full system dynamics. This is achieved by using artificial neural networks (ANN) to represent the boundary condition at the interface between neighboring sub-catchments. The approach is demonstrated with an application to a many-objective optimization problem in which sustainable drainage systems are used to expand the capacity of an existing drainage network. The evaluation of the objective function using the emulation model is found to be 22 times faster than using the physically based model, resulting in a significant speed-up of the optimization process. Unlike previously proposed optimization approaches that rely on surrogate models to emulate the objective functions, the proposed approach remains physically based for the individual sub-catchments, thus reducing the chance of bias in the optimization results.
Ensuring science-based climate action: Analysis of multi-stakeholder engagement in Nationally Determined Contributions
Authors: Cintron Rodriguez Isatis M.
Published: March 2021

Good environmental governance includes participatory, transparent and accountable decision-making. All sectors of society have an essential role in organizing climate action towards our shared future. Networking science into decision-making will allow us to build actionable resilience intelligence. Developed in 1992, Article 6 of the United Nations Framework Convention on Climate Change, Principle 10 of the Rio Convention, and the Article 12 of the 2015 Paris Agreement include specific mandates for public participation and engagement in climate actions. Governments have pledged, in international agreements, to broader public participation in environmental policy design processes facilitating access to information. Here we show how Latin-American countries are doing in regard to such responsibility by focusing on the reference to participatory processes and the inclusion in climate strategies of adequate instruments of participation in the contributions presented to the United Nations. This analysis provides a baseline from which we can ground truth and track progress of NDCs’ accelerating climate-smart future through stakeholder engagement. Our research shows there is a need for understanding and metrics for quality public participation and articulation of participatory processes
Mongolian peatland documents 5000-year pollution history and a baseline of Pb and Tl in northeastern Asia
Authors: Bao Kunshan , Qiang Mingrui , Zhao Kewei , Yan Ying , Ganzorig Ulgiichimeg , Batkhishig Ochirbat
Published: March 2021

Peat records of trace metals pollution history over thousands of years are not widely reported in northeastern Asia, although the mining/metallurgy have already started in the past 5000 years. Peat core was collected in September 2015, from the Nur Sphagnum bog, in Selenge province, in the NW part of the Kenthii Mountains, Mongolia. The Nur Sphagnum bog (49°39’N; 107°48’E; 1250 m.a.s.l.) is the largest wetland located in the mountain taiga forest of Mongolia in the northern part of the Hentei highlands. The mean January and July temperatures are -27.1°C and 18.3°C respectively, while mean annual precipitations are 288 mm. The peatland is composed of than 10 species of Sphagnum, while herb layer is dominated by Carex rostrata, and several species of Sphagnum. The dominant tree species are composed of Betulaplatyphylla, Pinussylvestris, Piceaobovata and Abiessibirica. As for the Nur bog, no research on elemental or isotopic geochemistry was undertaken currently. Our preliminary geochemical study established a baseline for typical heavy metal, Pb, 1.1 mg kg-1, which is reasonable to represent a pre-industrial background value in Mongolia, even in northeastern Asia. The average Pb content through the cores was 2.2 mg kg-1, which was significantly lower than the level in northeastern China and showed that the it was still typical area of pristine ecosystem in northern Mongolia. However, the elevation of Pb and Tl contents in the near surface layers was also observed, with an enrichment factor of 6, which suggested that the anthropogenic impact was approaching in this region and more attention should be paid to safeguard its nature heritage.
Impact of CMIP6 biomass burning emissions on Arctic sea ice loss
Authors: DeRepentigny Patricia , Jahn Alexandra , Holland Marika , Fasullo John , Lamarque Jean-François , Hannay Cécile , Mills Michael , Bailey David , Tilmes Simone , Barrett Andrew
Published: March 2021

The use of the Global Fire Emissions Database (GFED) from 1997-2014 to create the CMIP6 historical biomass burning (BB) forcing allows for a more accurate representation of BB emissions in climate models, but also results in an unrealistic increase in their inter-annual variability compared to pre- and post-GFED years, especially in the Northern Hemisphere mid-latitudes. We find that this new BB forcing affects the simulated Arctic sea ice loss in several CMIP6 models, bringing them into better agreement with the observed sea ice decline by leading to enhanced sea ice loss in the early 21st century. This suggests that BB emissions may have played a role in the acceleration of the observed early 21st century Arctic sea ice loss.

Using the Community Earth System Model version 2 (CESM2), we conduct sensitivity experiments in which we use BB emissions with a fixed annual cycle over the GFED period, to remove the inter-annual variability between 40-70°N. These experiments show that the strong acceleration in sea ice decline since the late 1990s simulated by the CESM2 is caused by enhanced Arctic warming driven by the increased variability in BB emissions over the GFED period. We also find that about half of the increase in sea ice sensitivity to CO2 and global mean surface temperature in the CESM2 compared to its CMIP5 counterpart, the CESM1, can be attributed to the change in BB emissions from CMIP5 to CMIP6, which suggests that the previously found improvement in sea ice sensitivity in CMIP6 models may in part be due to this new BB forcing and not only to changes in model physics. Overall, the results from this analysis highlight the influence of mid-latitude BB emissions on Arctic sea ice and provide new insights into the potential of a forced contribution to the observed accelerated early 21st century Arctic sea ice loss. Furthermore, this work highlights the importance of avoiding temporal discontinuities in prescribed aerosol forcing datasets as well as the need to better understand inter-model contrasts within the CMIP6 archive related to sensitivity to BB emissions.
Monthly streamflow reconstruction for the Chao Phraya River Basin with tree rings and δ180
Authors: Nguyen Hung , Galelli Stefano , Xu Chenxi , Buckley Brendan
Published: March 2021

The Chao Phraya River Basin covers a third of Thailand’s area and is also home to a third of the country’s population. The Chao Phraya River serves multiple purposes: water supply, irrigation, hydropower production, cooling for thermoelectric power plants, among others. Water management in the basin could benefit from long term streamflow records that extend beyond the instrumental period. But to acquire practical relevance, streamflow reconstructions should have a sub-annual resolution—in line with the time step characterizing water management decisions. To this end, we reconstruct 253 years of monthly streamflow at all four major tributaries (Ping, Nan, Yon, and Wang) of the Chao Phraya. The reconstructions are developed using a network of tree rings and δ180 chronologies in Southeast Asia. Importantly, our reconstruction method ensures that the total monthly flow matches the annual flow closely. This mass balance criterion is necessary to avoid misguiding water management decisions, such as the allocation of water rights. All reconstructions are skillful. Better skills are obtained in the pre-monsoon months (March to May) than in the peak monsoon season (September, October). Overall, this work presents the most comprehensive record of high resolution and long term streamflow variability in the basin.
Devonian magnetostratigraphy: new data and old problems
Authors: van der Boon Annique , Biggin Andy , Thallner Daniele , Hounslow Mark , Nawrocki Jerzy , Wójcik Kristyan , Paszkowski Mariusz , Königshof Peter , de Backer Tim , Kabanov Pavel , Gouwy Sofie , Vandenberg Richard
Published: March 2021

The global polarity time scale (GPTS) is relatively unconstrained for the Paleozoic, particularly the Devonian. Constraining the GPTS and reversal frequency for the Devonian is crucial for the understanding of the behaviour of Earth’s magnetic field. Furthermore, construction of a GPTS for the Paleozoic could provide a valuable tool for age determination in other studies. However, most paleomagnetic data from the Devonian is problematic. The data are difficult to interpret and don’t have a single easy to resolve (partial or full) overprint. Paleointensity studies suggest that the field was much weaker than the field of today, which could have been accompanied by many reversals (a hyperreversing field). In order to improve the geomagnetic polarity time scale in the Devonian, and quantify the number of reversals in this time, we sampled three Devonian sections in Germany, Poland and Canada. These sections show evidence that the rocks were not significantly heated, and they show little evidence for remineralisation. This minimises the chance the rocks were remagnetised after the Devonian. Our data show that even when rocks are well qualified to have reliably recorded the Devonian field, the interpretation is not straightforward. We also discuss problems with the Devonian GPTS as presented in the geologic timescale.
Multi-model superensemble projection of seasonal soil drought in the midst of various uncertainties
Authors: Chen Sisi , Yuan Xing
Published: March 2021

Seasonal drought has a serious impact on nature and human society, especially during vegetation growing periods. As climate change alters terrestrial hydrological cycle significantly, it is imperative to assess drought changes and develop corresponding risk management measures for adaptation. According to a series of warming targets proposed by IPCC, researchers have focused on the response of regional droughts to global warming, but with inconsistent conclusions due to the large uncertainties in soil moisture simulation by the climate models, and the difficulty in representing the internal variability of climate system by using multi-model ensemble, etc. As compared with Coupled Model Intercomparison Project Phase 5 (CMIP5) models, the future projection of soil moisture based on the latest CMIP6 shows opposite trends over parts of China. Therefore, we project seasonal soil drought over China by using the superensemble that includes a set of CMIP5 and CMIP6 soil moisture data, high resolution land surface simulations driven by bias-corrected CMIP5 climate forcings, as wells large ensemble (LE) simulation data. We also investigate the influences from internal variability, and model uncertainties in responding to global warming at different levels.
An ichnological predictive map of the Jezero Crater, Mars: searching for potential traces of life-substrate interactions based on terrestrial analogues (Liguria, Italy; Naturtejo UNESCO Geopark, Portugal; Ômnôgov, Mongolia)
Authors: Baucon Andrea , Neto De Carvalho Carlos , Briguglio Antonino , Felletti Fabrizio , Piazza Michele
Published: March 2021

Seeking signs of past life in the geological record of Mars is one of the four primary goals of the NASA Mars 2020 mission. However, scant attention has been paid to the fossilized products of life-substrate interactions (ichnofossils), which are one of the most abundant and reliable biosignatures on Earth. This lack of attention is surprising because the ichnofossil heritage does not include only metazoan tracks, but also macroscopic burrows produced by bacteria, microborings ascribed to the activity of bacteria and fungi, and biostratification structures produced by archaea, cyanobacteria and euglenozoans. In light of this gap, the goal of the present study is evaluating the suitability of the Mars 2020 Landing Site for ichnofossils. To this goal, this work applies palaeontological predictive modelling, a technique used to predict the location of fossil sites in uninvestigated areas on Earth. Accordingly, a GIS of the landing site is developed. Each layer of the GIS maps the suitability for one or more ichnofossil types (bioturbation, bioerosion, biostratification structure) based on an assessment of a single attribute (suitability factor) of the Martian environment. Suitability criteria have been selected among the environmental attributes that control ichnofossil abundance, preservation, and accessibility in W Liguria (Italy), Naturtejo UNESCO Geopark (Portugal), and Ômnôgov district (Mongolia). The goal of this research will be delivered through a predictive map showing which areas of the Mars 2020 landing site are more likely to preserve ichnofossils. This map can be used to guide future efforts to the regions of the Mars 2020 Landing Site with the highest ichnological potential, realizing benefits in life-search efficiency and cost‐reduction.
Development of a Three-Source Remote Sensing Model for Estimation of Urban Evapotranspiration (TRU)
Authors: Chen Han , Huang Jinhui Jeanne , McBean Edward , Lan Zhiqing , Gao Junjie , Li Han , Zhang Jiawei
Published: March 2021

Evapotranspiration (ET) from an urban area and its components are important  when estimating the urban ‘heat island’ effect and the urban hydrological cycle. Multi-source satellite-based ET models for ecosystems (e.g. farmland, forest, and wetland) have been developed and applied, but satellite-based ET model dimensions for urban areas are lacking, especially since all currently available models are designed for single-source schemes. This paper proposes the first Three-source Remote sensing model for Urban areas (TRU) to discriminate between soil evaporation, vegetation transpiration, and impervious surface evaporation. TRU uses a new parameterization scheme, based on the use of a complementary relationship integrating soil surface temperature to estimate soil evaporation. An iterative procedure was developed for decomposing land surface temperature (LST) into component temperatures. Also, the ET for impervious areas was independently delineated using the “patch” approach. The model was tested for 45 cloudless days in Tianjin for 2017-2020 based on 30 m Operational Land Imager (OLI)/Enhanced Thematic Mapper Plus (ETM+) images. Results indicated the root mean square error (RMSE) of 38.8 W/m2 and Bias of 9.9 W/m2 compared with two Eddy Correlation (EC) observations for instantaneous latent heat (LE) simulation and RMSE was 0.087 and Bias was -0.012, compared with stable water isotope measurements for the estimation of the ratio of vegetation latent heat flux to latent heat flux (LEv/LE).Comparison with urban single-source models and two-source models for ecosystem suggest TRU provide best accuracy for ET and its components simulation. The spatial pattern suggested impervious surface evaporation exhibited minimal seasonal variation and maintained a very lower level due to limited availability of water. The results emphasized the importance of using land use and land cover (LULC) in urban ET modeling and the necessity to calculate ET as independent of impervious areas. TRU represents a groundbreaking development of multi-source urban satellite-based ET models and facilitates the mapping of urban ET components.
Drought legacy effects on vegetation growth in Yunnan Province, China
Authors: Dong Bogang , Yu Yang
Published: March 2021

Climate change is leading to significant changes in the intensity and frequency of drought events, and the key processes of terrestrial ecosystems are directly affected by the uncertainty of extreme climate events. In 2009-2010, Southwest China suffered a once-in-a-hundred-years extreme drought, but the response of vegetation to this drought event on a long-term scale is still unclear. Using multi-year moderate resolution imaging spectrometer (MODIS) normalized difference vegetation index (NDVI) data and meteorological data, the duration of legacy effect of 2009-2010 extreme drought in Yunnan Province were studied and the response difference of diverse vegetation types were analyzed. The results showed that 1）The inhibition of vegetation growth occurred about 2 years in Yunnan Province after the extreme drought event, especially in areas where precipitation experienced a severe reduction. 2）The most sensitive area of vegetation response to drought events is around 2000 m above sea level, and the vegetation growth above 4000m is almost unaffected. 3）Compared with grassland and farmland, the inhibition of forest vegetation is stronger. This research revealed the negative impact of extreme drought on the growth of vegetation in Yunnan Province and provided a theoretical basis for coping with extreme drought and restoring vegetation effectively in the future.
Determining optimum wave velocity from sparse CMP automatically by coupling POCS interpolation and NMO correction: application to array antenna GPR data collected during in-situ infiltration test
Authors: Oikawa Koki , Saito Hirotaka , Kuroda Seiichiro , Takahashi Kazunori
Published: March 2021

As an array antenna ground penetrating radar (GPR) system electronically switches any antenna combinations sequentially in milliseconds, multi-offset gather data, such as common mid-point (CMP) data, can be acquired almost seamlessly. However, due to the inflexibility of changing the antenna offset, only a limited number of scans can be obtained. The array GPR system has been used to collect time-lapse GPR data, including CMP data during the field infiltration experiment (Iwasaki et al., 2016). CMP data obtained by the array GPR are, however, too sparse to obtain reliable velocity using a standard velocity analysis, such as semblance analysis. We attempted to interpolate the sparse CMP data based on projection onto convex sets (POCS) algorithm (Yi et al., 2016) coupled with NMO correction to automatically determine optimum EM wave velocity. Our previous numerical study showed that the proposed method allows us to determine the EM wave velocity during the infiltration experiment.

The main objective of this study was to evaluate the performance of the proposed method to interpolate sparse array antenna GPR CMP data collected during the in-situ infiltration experiment at Tottori sand dunes. The interpolated CMP data were then used in the semblance analysis to determine the EM wave velocity, which was further used to compute the infiltration front depth. The estimated infiltration depths agreed well with independently obtained depths. This study demonstrated the possibility of developing an automatic velocity analysis based on POCS interpolation coupled with NMO correction for sparse CMP collected with array antenna GPR.
Gravity Measurements of the Juno Spacecraft Matched with Jupiter Models that rely on a Dilute Core and Deep Winds
Authors: Militzer Burkhard , Wahl Sean , Hubbard William
Published: March 2021

Since its arrival at Jupiter in 2016, the Juno spacecraft has measured the planet’s gravity fields with unprecedented precision. The interpretation of these measurements has been challenging because the magnitudes of the gravity coefficients J4 and J6 were smaller than predicted by traditional interiors models that included a dense inner core composed of rock and ice. Here we instead present models with dilute cores [Geophys. Res. Lett. 44 (2017) 4649] and deep-winds that conform to theoretical predictions of hydrogen-helium phase separation in the interior layer from approximately 0.8 to 0.85 Jupiter radii. Such models match the entire set of zonal gravity measurements by the Juno spacecraft. Our work is based on the accelerated version of the Concentric Maclaurin Spheroid method [Astrophysical J. 879 (2019) 78]. We conclude by comparing with models for Saturn’s interior. 