bluuebunny/crossref_metadata_2025 huggingface dataset:
Fire regime impacts on post-fire diurnal land surface temperature change over North American boreal forest
Authors: Zhao Jie , Yue Chao , Ciais Philippe , Hou Xin , Tian Qi
Published: March 2021

Wildfire is the most prevalent natural disturbance in the North American boreal (BNA) forest and can cause post-fire land surface temperature change (ΔLSTfire) through biophysical processes. Fire regimes, such as fire severity, fire intensity and percentage of burned area (PBA), might affect ΔLSTfire through their impacts on post-fire vegetation damage. However, the difference of the influence of different fire regimes on the ΔLSTfire has not been quantified in previous studies, despite ongoing and projected changes in fire regimes in BNA in association with climate change. Here we employed satellite observations and a space-and-time approach to investigate diurnal ΔLSTfire one year after fire across BNA. We further examined potential impacts of three fire regimes (i.e., fire intensity, fire severity and PBA) and latitude on ΔLSTfire by simple linear regression analysis and multiple linear regression analysis in a stepwise manner. Our results demonstrated pronounced asymmetry in diurnal ΔLSTfire, characterized by daytime warming in contrast to nighttime cooling over most BNA. Such diurnal ΔLSTfire also exhibits a clear latitudinal pattern, with stronger daytime warming and nighttime cooling one year after fire in lower latitudes, whereas in high latitudes fire effects are almost neutral. Among the fire regimes, fire severity accounted for the most (43.65%) of the variation of daytime ΔLSTfire, followed by PBA (11.6%) and fire intensity (8.5%). The latitude is an important factor affecting the influence of fire regimes on daytime ΔLSTfire. The sensitivity of fire intensity and PBA impact on daytime ΔLSTfire decreases with latitude. But only fire severity had a significant effect on nighttime ΔLSTfire among three fire regimes. Our results highlight important fire regime impacts on daytime ΔLSTfire, which might play a critical role in catalyzing future boreal climate change through positive feedbacks between fire regime and post-fire surface warming.
Phosphorus Leaching effects of organic and mineral fertilizers on a clay loam soil through in-situ soil columns
Authors: Wang Hongyan , Chen Xin , Chi Guangyu
Published: March 2021

The leaching pattern of phosphorus (P) from continuous fertilization is generally neglected in heavy-textured soils. Generally speaking, P is hard to migrate vertically compared with nitrogen (N) and potassium (K) especially in clay loam soils. However, our study has proved that P could be leached to the depth of 1 m below the groundwater under circumstances of heavy rainfalls and large temperature differences. Our research is based on in-situ soil column experiments to estimate the effects of soil P leaching in typical fertilization regimes of Northeastern China. Fertilization treatments include CK (No fertilizer), NPK (900 kg ha-1 of compound fertilizer), NPKS (NPK + straw return), NPKSM (NPK + straw return + 7.5 ton ha-1 of dried cattle manure compost), 80% NPKS (720 kg ha-1 of compound fertilizer + straw return), 80%NPKSM2 (720 kg ha-1 of compound fertilizer + straw return + 15 ton ha-1 of dried cattle manure compost). In 2019 and 2020, we collected 10 leachates of each treatment and determined the concentrations of TP (Total P), TDP (Total dissolved P), PP (Particle P), SRP (soluble reactive P), and DOP (dissolved organic P). The results showed that P leaching has obviously occurred after 5-year continuous fertilization, with the leaching ratio accounted for 0.61%-2.2% of total P input, and the ratio of PP to TDP was about 1:1. Furthermore, the leaching loss caused by chemical fertilizer was equivalent to that of straw application and low-dose manure fertilizer, while high-dose manure application significantly caused more P leaching losses than the other treatments. What’s more, manure addition mainly promoted the vertical movement of PP, while straw application chiefly increased the leaching ratio of TDP. 20% reduction of chemical fertilizer significantly reduced the leaching loss of TDP, with a ratio of 16%-17% compared to full-scale chemical fertilizer. Overall, in terms of slightest environment risks from P loss via leaching in this study, the excessive manure application appears to pose a long-term risk of vertical P migration than the inorganic fertilizer and straw amendment.
Unravelling socio-hydrological processes behind cascading drought-to-flood disasters
Authors: Van Loon Anne , Matanó Alessia , di Baldassarre Giuliano , Day Rosie , Garcia Margaret , Rohse Melanie , de Ruiter Marleen , Koehler Johanna , Ward Philip
Published: March 2021

Future climate projections show a strengthening of the hydrological cycle with more droughts and floods expected in many regions of the world. This means a higher likelihood of cascading drought-to-flood disasters such as the Millennium Drought – Brisbane flooding in Australia or the California drought – Oroville spillway collapse in the US. Droughts allow ample time for impacts and adaptation, which influence hazard, exposure, and vulnerability of a subsequent flood. When we treat the flood risk as independent from the drought this might lead to large underestimations of future risk.

Here, we present the PerfectSTORM project (‘STOrylines of futuRe extreMes’). In this project we will study drought-to-flood events to provide the understanding needed to prevent major disasters in the future. We will use a mixed-methods approach based on a combination of qualitative and quantitative storylines of past and future drought-to-flood risk in case studies and extrapolation of this rich case study information to the global scale. Qualitative storylines will be collected with narrative interviews and mental simulation workshops and will be analysed to develop timelines and causal loop diagrams. Quantitative storylines will be developed from timeseries of hydrological and social data that will be analysed to distinguish interrelated drivers and modelled with system dynamics modelling. These storylines will then be combined in an iterative way using innovative data visualisation as a basis for co-creating management solutions.

To generalise our case study understanding, a range of global datasets will be analysed to find global types and hotspots of drought-to-flood events. This information will be combined with the system dynamics model developed in the case studies and a global multi-dimensional possibility space will be developed. This will allow us to explore positive pathways for future management of drought-to-flood events in different parts of the world. The PerfectSTORM project will provide in-depth understanding of the hydrosocial feedbacks and dynamic vulnerability of cascading hazards.
Feedback Mechanisms between Heterogeneous Geothermal Heat Fluxes and the Dynamic Ice Sheet Reinforce the Formation of Tunnel Valleys
Authors: Bodenburg Sascha Barbara , Reiche Sönke , Hübscher Christian , Kowalski Julia
Published: March 2021

The large variety of subglacial landforms observed on Earth are due to a complex interplay between the overlying ice sheet and the solid Earth below. While the ice cover thermally isolates the subglacial region, hence shields it from any influence by variations in the atmosphere, spatially varying geothermal heat fluxes from below may lead to the formation or reinforcement of existing subglacial landform patterns, such as tunnel valleys. An observed spatial correlation between tunnel valleys and underlying salt structures in the North German Basin is often explained mechanically. In this work, we alternatively focus on the role of heat transfer for the formation of tunnel valleys, which has not been holistically investigated until now. As salt has a higher thermal conductivity than the surrounding rocks, a local concentration of geothermal energy above salt structures may lead to increased subglacial melting rates of the overlying ice sheet. In particular, it is our goal to investigate to which extent the resulting meltwater discharge and corresponding erosion has the potential to reinforce tunnel valley formation. For our analysis, we develop a coupled computational strategy capable of determining the interplay between the temperature distribution within the heterogeneous subsurface including heat transport and ground water flow, and the overlying ice sheet. Modelling the interfacial heat flux from the subsurface into the ice sheet then allows us to infer on subglacial melt rates, which can be further assessed with respect to their role in the formation of tunnel valleys. In this contribution, we present results of a scaling analysis that takes into account the ice sheet with its internal horizontal and vertical velocity fields, the subsurface and the subglacial interfacial area. We furthermore describe a 1D computational strategy to combine the heat transport including subglacial phase change into a coupled process model allowing for investigating feedback mechanisms. Finally, we discuss strategies how this can be integrated into a full dimensional computational subsurface model, such as SHEMAT-Suite. Preliminary results for two tunnel valleys overlying salt structures in the German North Sea show that the local concentration of geothermal energy solely basing on heat conduction is only slightly augmented. The role of hydrothermal flow processes still remains to be quantified. We can therefore conclude that the geothermal distribution has a complementary effect to mechanical processes together leading to the formation of tunnel valleys.
The role of anisotropy in oceanic lithosphere from 'cradle to grave'
Authors: Kalnins Lara M. , Simons Frederik J. , Farangitakis Georgios-Pavlos , Richards Fred D.
Published: March 2021

The oceanic crust and lithosphere are commonly treated as geologically simple, their fundamental properties encapsulated by the 1D model of layered oceanic crust and the plate-cooling model of lithospheric thickness we learnt as undergraduates. The question of directionality or anisotropy in the behaviour and deeper structure of oceanic plates is relatively rarely considered, despite formation processes, such as rifting and seafloor spreading, and surface topography, such as abyssal hills, that are clearly highly anisotropic. In this presentation, we bring together evidence from a variety of sources from regional studies of rifting and volcanism to numerical modelling and global analyses of bathymetry and gravity data. We show how anisotropy is imprinted into the oceanic lithosphere at formation, both in the early rifting phases and at mature spreading centres, and how that anisotropic signature persists for many millions of years, potentially strengthened by preferential alignment of mineral phases as the moving plates cool and thicken. We then consider how this directionality impacts later deformation, volcanism, and eventually subduction.
A reduced-complexity model of fluvial inundation with a sub-grid representation of floodplain topography evaluated for England, United Kingdom
Authors: Dadson Simon , Blyth Eleanor , Clark Douglas , Davies Helen , Ellis Richard , Lewis Huw , Marthews Toby , Rameshwaran Ponnambalan
Published: March 2021

Timely predictions of fluvial flooding are important for national and regional planning and real-time flood response. Several new computational techniques have emerged in the past decade for making rapid fluvial flood inundation predictions at time and space scales relevant to early warning, although their efficient use is often constrained by the trade-off between model complexity, topographic fidelity and scale. Here we apply a simplified approach to large-area fluvial flood inundation modelling which combines a solution to the inertial form of the shallow water equations at 1 km horizontal resolution, with two alternative, simplified representations of sub-grid floodplain topography. One of these uses a fitted sub-grid probability distribution, the other a quantile-based representation of the floodplain. We evaluate the model’s steady-state performance when used with flood depth estimates corresponding to the 0.01 Annual Exceedance Probability (AEP; ‘100-year’) flood and compare the results with published benchmark data for England. The quantile-based method accurately predicts flood inundation in 86% of locations, with a domain-wide hit rate of 95% and false alarm rate of 10%. These performance measures compare with a hit rate of 71%, and false alarm rate of 9% for the simpler, distribution-based method. We suggest that these approaches are suitable for rapid, wide-area flood forecasting and climate change impact assessment.
Using Airborne Laser Scanning to characterize different land uses in a tropical landscape based on their structural complexity
Authors: Camarretta Nicoló , Ehbrecht Martin , Wenzel Arne , Zuhdi Mohd , Merk Miryam S. , Schlund Michael , Knohl Alexander , Erasmi Stefan
Published: March 2021

Accurate characterization of land use and land cover (LULC) is important in a rapidly changing environment such as the Indonesian tropics. Over the past 30 years, native tropical forests have been cleared and replaced by fast-growing cash-crops, such as oil palm and rubber plantations. This change in land use dramatically alters the vegetation structure of the entire region. Vegetation structural complexity is highly variable in tropical forests, and provides habitat to a large number of native species. In addition, vegetation structure has an impact on micro-climate and the exchange of greenhouse gases (GHG), water and energy. Measuring vegetation structure in the field can be costly and time consuming, particularly in remote, inaccessible areas of tropical forest. In contrast, Airborne Laser Scanning (ALS) can provide very detailed three-dimensional information on forest structure without the need to reach remote areas in the field. Here, we aim to study the potential of ALS-derived measures of structural complexity as ecological indicators to highlight differences in forest structure across a gradient of LULC in Sumatra, Indonesia. We analysed the structural complexity of four main LULC types relevant to the region: tropical secondary forests, rubber agroforests, oil palm plantations and shrublands. Several structural metrics have been extracted from ALS data over 136 circular 0.1 ha plots (34 plots per LULC type): top height, height percentiles, rumple index, leaf area index (LAI), effective number of layers (ENL), vegetation cover, number of gaps. Results from a Principal Component Analysis (PCA) indicated number of gaps to be a major driver associated with the occurrence of oil palm plantations, while higher values of key structural metrics, such as top height, LAI and ENL were strongly linked with the presence of secondary tropical forest plots. Furthermore, a clear separation in metrics behaviour between forest and oil palm plots was evident from the pairwise comparison of these metrics, with rubber and shrubland plots behaving similarly to either forests or oil palm plantings according to different metrics. Our results show clear distinctions in several structural attributes among different LULC, which indicate the need for careful considerations regarding the impact of land-use change on ecosystem functioning, biodiversity and climate.
Linking the dynamic expansion and contraction of stream networks to changes in water storage and water quality in a pre-Alpine catchment
Authors: Bujak Izabela , Rinaldo Andrea , van Meerveld Ilja , Käslin Florian , von Freyberg Jana
Published: March 2021

Many headwater catchments are characterized by temporary streams that flow only seasonally or during rainfall events. As a result, the network of flowing streams is a dynamic system that periodically expands and contracts. This dynamic is likely to affect water flow and composition: the expansion of the stream network enhances the hydrologic connectivity of hillslopes to the streams, which facilitates shorter transit times. Also, the onset of flow in previously dry streambeds can cause flushing of sediments and nutrients. However, our knowledge of the relationships between flowing stream network dynamics and water quantity and quality in headwater catchments is still limited because experimental data remain sparse.

Within the TempAqua project we investigate the processes that drive stream network dynamics by relating measurements of stream network geometry to changes in catchment water storage and stream water quality. For this, we monitored the flow state, discharge, groundwater levels, soil moisture, and precipitation in three (3-7 ha) headwater catchments in the northern Swiss pre-Alps (Alptal catchment) in summer and fall 2020 using a wireless sensor network. To obtain high-resolution data of the dynamic stream network, we did multiple mapping surveys using a self-developed mobile phone application. Moreover, we sampled streamwater and precipitation at an hourly resolution during rainfall events at multiple locations to quantify the short-term changes in water quality when the stream network expands. We will present our research activities in the Alptal catchment and discuss the initial results obtained from the combined monitoring of the flowing stream network and hydrometric and hydrochemical variables.
Whole-tree rainfall interception measured directly by gravimetry and its relationship with plant traits
Authors: Pflug Stefanie , Voortman Bernard R. , Witte Jan-Philip M.
Published: March 2021

Rainfall interception by vegetation is influenced by rainfall characteristics, plant traits such as crown architecture and leaf area index, and the interaction between them. We determined the cumulative seasonal interception, interception loss (interception:gross precipitation) and canopy storage capacities of 7 temperate deciduous broadleaved (Acer pseudoplatanus L., Betula pendula Roth, Carpinus betulus L., Fagus sylvatica L., Populus tremula L., Sorbus aucuparia L.) and 3 evergreen coniferous tree species (Picea abies (L.) Karsten, Pinus sylvestris L., Pseudotsuga menziesii (Mirb.) Franco). Furthermore, the relationship between interception and tree traits such as crown projected area, branch angle, branch length and density and branch surface area was analysed.

Whole-tree interception was measured directly on potted trees in the Netherlands. One tree of each species had been placed on a weighing balance in an outdoor setting, thereby receiving natural rainfall. Tree size ranged from 2 to 8 m and measurements were done for 7 consecutive months.

Our results show that a) the coniferous species had larger canopy storage capacities and larger interception losses than the broadleaved species, b) the cumulative interception (in kg) of the broadleaved species was positively related to stem diameter at breast height, tree height, crown depth, maximum branch length and the total branch surface area, c) cumulative interception (in mm) of both broadleaved and coniferous species was positively related to branch number, branch length and branch surface area corrected for the respective crown projected area. These results can be used to estimate interception capacity from plant traits and to simulate interception losses of trees in a more reliable manner.
Large-scale versus regional drivers of climate change in the Lake Victoria basin
Authors: Van de Walle Jonas , Thiery Wim , P.M. van Lipzig Nicole
Published: March 2021

Severe thunderstorms pose a constant threat to more than 30 million people living along the shores of Lake Victoria (East Africa). Thousands of fishermen lose their lives on the lake every year, and capsizing accidents with passenger ferries and transport boats are frequently reported. Moreover, hazardous thunderstorms affect people living inland, continuously facing flood risks.

In this data scarce region, atmospheric models are particularly useful tools to better understand the region’s complex climate, especially when simulated at convection-permitting resolution. For example, such models already demonstrated the importance of the lake in determining the diurnal precipitation cycle, and highlighted the role that mountain blocking of easterly trade winds plays in explaining the regional rainfall pattern.

Such models also allow us to generate high-resolution future projections for this region. In this study, a surrogate global warming approach has been applied. In a first simulation, the ensemble mean of the recent global climate projections from the CMIP6 data set was used to perturb the lateral boundary conditions from the ERA 5 reanalysis. In this ensemble mean, variations in (large scale) atmospheric dynamics are negligible and the climate change signal is mainly determined by the increased water vapour related to the warming and the response of the mesoscale circulation to differential lake/land heating. Specifically, while increased water vapour tends to increase total precipitation, weakened mesoscale circulation makes the over-lake rainfall to reduce instead. In a second simulation, a CMIP6 member with larger large-scale dynamical changes in the region was chosen to perturb the ERA5 lateral boundary data, thereby changing both the thermodynamics and the dynamical fields. Combining both simulations enables us to study the effects of changed large-scale dynamics and its interaction with the mountain peaks on mean and extreme precipitation in the region, thereby gaining insight in expected future changes of the region’s hazardous thunderstorms.
Analysis of porosity and pore connectivity of soil microaggregates by intrusion of the molten alloy Wood´s metal
Authors: Dultz Stefan , Gentsch Norman , Bode Marie , Woche Susanne K. , Fechner Alexander , Kaiser Klaus , Mikutta Robert , Guggenberger Georg
Published: March 2021

The limited exchange of dissolved matter with the interior of soil microaggregates (SMA) due to narrow pores of high tortuosity result in spatial biogeochemical gradients from outer towards inner SMA surfaces. The goal of our study was to analyze pore space characteristics in SMA by visualization and quantification of connected “open” versus closed pore structures in each of the pore size classes <10, 10-100 and >100 µm². SMA ranging in size between 20 and 250 µm were isolated along a soil clay content gradient (19-35%) and investigated by using a porosimetry technique with a molten alloy, called Wood´s metal, which solidifies below 78°C. The alloy was pressed into connective pores of SMAs by applying an Ar pressure of 55 MPa, allowing an intrusion of pores with a diameter below ~20 nm. After alloy solidification, polished sections of intruded SMA were analyzed by confocal laser scanning microscopy (Keyence, VK-9700) and the ImageJ software was used to quantify open and closed pores by segmenting grayscale histograms. The SMA typically consisted of two different sections, where particle arrangements are loose or dense. Coarse-sized aggregate-forming materials were observed in sections with loose particle arrangements, where pores appear well connected. Part of the coarse SMAs >100 µm show large circular structures with dense particle arrangements in the edge region. These dense arrangements contain high shares of layer silicates and reveal closed pore structures. The total SMA porosity was up to 40 area-%. The share of closed pores <20 nm in diameter ranged typically from 20 to 40 % of total porosity. Pore systems >100 µm² had the highest share within the open pores, while pore system <10 µm² showed the largest share of closed pores. The proportion of closed pores to total porosity decreased for SMA sizes < 50 µm. Our results show that, in addition to an extended connective pore system, SMA also exhibit sections with high contents of clay minerals, where the pore size distribution is narrow (<20 nm) and tortuosity high. Here, element transport and habitation by microorganisms might be impaired, resulting in larger conservation potential for organic matter.
Assessment of spatiotemporal patterns of gross primary productivity in the arctic and boreal ecosystems using multi-source products
Authors: Huang Yan , Yu Zhitong , Hu Luojia , Yao Wei
Published: March 2021

Since an increasing number of global gross primary productivity (GPP) products have become available and been applied in climate change research, there is an urgent need to compare their performance in capturing spatial and temporal variability, especially in the regions where the number of training data is limited or model parameters are of relatively larger uncertainty. Here, we investigated the spatial patterns of interannual trends and variations, and seasonal-cycle amplitudes of GPP in the arctic and boreal zones, and explored the differences across various GPP products during the overlapping period (2000−2010). We compared three main types of state-of-the-art GPP products, including simulations derived from terrestrial biosphere models of the Multi-scale Synthesis and Terrestrial Model Intercomparison Project using drivers under different scenarios, 3 datasets up-scaled from FLUXNET eddy covariance measurements based on machine-learning algorithms, and 2 semi-empirical or empirical remotely sensed products based on different satellite data. We also examined the differences of GPP variability across the main ecosystem types, mainly including tundra and taiga, and assessed the contributions of different ecosystems to the temporal variations of total GPP in this zone. The results showed all the products could capture the interannual and seasonal variability of GPP, but the spatial patterns varied largely, which was in-deep discussed. This study will benefit the usage of the GPP products in the carbon cycle research for the arctic and boreal ecosystems.
Towards a better understanding of Siberian wildfires: linking paleoenvironmental fire reconstructions with an individual-based spatially explicit fire-vegetation model
Authors: Glückler Ramesh , Dietze Elisabeth , Gloy Josias , Herzschuh Ulrike , Kruse Stefan
Published: March 2021

Wildfires are an essential ecological process, located at the interface between atmosphere, biosphere, and geosphere. Climate-related changes in their appearance and frequency will shape the boreal forest of tomorrow, the largest terrestrial biome responsible for numerous important ecosystem functions. Changing fire regimes could also increase pressure on fire management and become a threat for humans living in Siberia. However, a lack of long-term fire reconstructions complicates the understanding of the main drivers in the larch-dominated forests of eastern Siberia. At the same time, this lack of long-term understanding also aggravates the validation of fire-vegetation models, and thus predictions of future changes of fire regimes in this vital region.

Here, we present a new fire module being built for the individual-based, spatially explicit vegetation model LAVESI (Larix Vegetation Simulator). LAVESI is able to simulate fine-scale interactions in individual tree’s life stages and detailed population dynamics, now expanded by the ability of wildfires igniting and damaging biomass. Fire-vegetation simulations were computed around the catchment of Lake Khamra (SW Yakutia), which experienced forest fires in the years 2007 and 2014 according to remote sensing imagery. From the lake, we previously contributed a new, sedimentary charcoal-based fire reconstruction of the late Holocene. Testing the fire module at a current study site, where modern and historic data has already been collected, allows us to improve it, and look into ways in which the fire reconstruction might help inform the model, before eventually scaling it up to cover larger regions. This represents a first step towards a reliable fire-vegetation model, able to predict future impacts of fires on both the forests of eastern Siberia, as well as the humans living there.
Forecasting long-term shoreline evolution in highly antrhopized coastal areas
Authors: Álvarez-Cuesta Moisés , Toimil Alexandra , Losada Iñigo J.
Published: March 2021

A new numerical model for addressing long-term coastline evolution on a local to regional scale on highly anthropized coasts is presented. The model, named IH-LANS (Long-term ANthropized coastlines Simulation tool), is validated over the period 1990-2020 and applied to obtain an ensemble of end-of-century shoreline evolutions. IH-LANS combines a hybrid (statistical-numerical) deep-water propagation module and a shoreline evolution model. Longshore and cross-shore processes are integrated together with the effects of man-made interventions. For the ease of calibration, an automated technique is implemented to assimilate observations. The model is applied to a highly anthropized 40 km stretch located along the Spanish Mediterranean coast. High space-time resolution climate data and satellite-derived shorelines are used to drive IH-LANS. Observed shoreline evolution (<10 meters of root mean square error, RMSE) is successfully represented while accounting for the effects of nourishments and the construction and removal of groynes, seawalls and breakwaters over time. Then, in order to drive the ensemble of end-of-century shoreline evolutions, wave and water level projections downscaled from different climate models for various emissions scenarios are employed to force the calibrated model. From the forecasted shoreline time-series, information from multiple time-scales is unraveled yielding valuable information for coastal planners. The efficiency and accuracy of the model make IH-LANS a powerful tool for management and climate change adaptation in coastal zones.
When the science meets art – a report from the creation of comics about Earthquakes and Geomagnetic field
Authors: Machek Matej , Kučerová Karolína , Brož Petr , Lukačovičová Lucie , Píša David
Published: March 2021

As science communicators we are confronted with little attention paid to the understanding of the Earth inner processes in the educational system of the Czech Republic. For that reason, we thought about ways how to explain basic principles of the Earth dynamics in accessible way to the school students and high school youth. We saw comics as an attractive way that would overcome the gap between knowledge and the need to entertain the young readers. We also thought that in the comics we should not be tell all everything with lot of explanatory text, but rather to try to provoke the reader to look for information and answers and hence to start the passion for science. So, we are trying to explain by graphics.

The presented experience covers the collaboration among three researches, graphic designer and writer in the process of creation of two short comic books about earthquake origin and inner structure of the Earth and origin of the Earth magnetic field.

We believe that such collaboration – to be effective – needs to be founded on several principles. The base of the comics, the storyboard, needs to be the result of discussions and collective effort of all participants. The artists need to be given creative freedom and the researchers should explain how the processes work inside the Earth rather than to try to push forward their views of artistic expression of them. Also, mainly the researches need to accept the equality of roles during the creative process. Last but not least the friendly atmosphere helps a lot.

The first comics “When the Earth Quakes” was created during second half of year 2019 and first months of year 2020 so the work was mostly based on personal meetings. The second comics is in production during diverse lockdowns and thus most of the communication is realized online. Therefore, different types of communication will be reflected based on our experience.   

The comics “When the Earth Quakes” and related board game is published under the Creative Commons license: https://www.ig.cas.cz/en/outreach/comics-seismic-wave/
Validation of Satellite Rainfall Estimates over Equatorial East Africa
Authors: Ageet Simon , Fink Andreas , Maranan Marlon
Published: March 2021

The sparsity of rain gauge (RG) data over Africa is a known impediment to the assessments of hydro-meteorological risks and of the skill of numerical weather prediction (NWP) models. Satellite rainfall estimates (SREs) have been used as surrogate fields for a long time and are continuously replaced by more advanced algorithms.  Using a unique daily rainfall dataset from 36 stations across equatorial East Africa for the period 2001–2018, this study performs a multi-scale evaluation of gauge-calibrated SREs, namely, Integrated Multi-satellite Retrieval for Global Precipitation Measurement (GPM) (IMERG), Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), Climate Hazards group Infrared Precipitation with Stations (CHIRPS) and Multi-Source Weighted-Ensemble Precipitation (MSWEP). Skills were assessed from daily to annual timescales, for extreme daily precipitation, and for the TMPA and IMERG near real-time (NRT) products. Results show that: 1) the satellite products reproduce the annual rainfall pattern and seasonal rainfall cycle well, despite exhibiting biases of up to 9%; 2) IMERG is the best overall for shorter temporal scales (daily, pentadal and dekadal) while MSWEP and CHIRPS perform best at the monthly and annual timesteps, respectively; 3) the SREs’ performance, especially in MSWEP, shows high spatial variability likely due to the variation of weights assigned during gauge calibration; 4) all the SREs miss between 57% (IMERG NRT)  and 83 (CHIRPS) of daily extreme rainfall events recorded in the RGs; 5) IMERG NRT outperforms all the other products regarding extreme event detection and accuracy; and 6) for assessing return values of daily extreme values, IMERG and MSWEP are satisfactory while the use of CHIRPS cannot be recommended. The study highlights some improvements of IMERG over its predecessor TMPA and the potential of Multi-Source Weighted-Ensembles products such as MSWEP for flood risk assessment and validation of NWP rainfall forecasts over East Africa.
Role Of Relative Wind Stress In Generating Eddy Instabilities
Authors: Wilder Thomas , Zhai Xiaoming , Joshi Manoj , Munday Dave
Published: March 2021

Relative wind stress (calculated by including the surface current terms) is known to remove energy from mesoscale eddies, but how they respond to this damping mechanism over their lifetime is poorly understood. A method for predicting eddy energy is made by time stepping forward the energy equation of a linear two-layer model using an analytical relative wind stress damping term. Results of this prediction are then compared with numerical experiments of an idealised two-layer anticyclonic eddy in a high-resolution general circulation model. The energy in both experiments displays a quantitative agreement in relative wind stress damping, though this is not the case when the eddy in the numerical experiment becomes baroclinically unstable. In addition to this well-known relative wind stress damping mechanism, we found that relative wind stress can trigger eddy instabilities sooner, leading to quicker decay. The earlier onset of these instabilities by relative wind stress is observed in a Lorenz energy cycle.
The transformation of a steepland river valley following an earthquake-triggered landslide near Kaikōura, NZ
Authors: Tunnicliffe Jon , Howarth Jamie , Massey Chris
Published: March 2021

In the relatively short and steep catchments of New Zealand’s Alps and Front Range, river systems traverse several process domains, from steep boulder-bed cascades to shallower braided range-front streams. Headwater streams (slope gradient >0.1 m·m-1) typically operate in a state of ‘supply limited’ conditions, where the river’s ability to carry sediment far exceeds the supply of material from upstream. With the catastrophic delivery of 13M m3 of landslide detritus following the 2016 7.8 Mw Kaikōura Earthquake, a tributary of the upper Hapuku River was filled to depths of up to 30 m, as debris spilled 1 km downstream from the delivery point. Nine airborne LiDAR surveys along the 12 km corridor have captured the transformation of the system from step-pool cascade to an unstable aggrading braidplain deposit to a vigorously incising channel, within four years of the event. With this rare window into disequilibrium conditions, we document the dramatic shifts in channel behaviour and dramatic reworking of the debris train following the landslide. There are two distinct phases: (1) a highly dynamic and unstable aggradation phase, with supply from upstream greatly exceeding river transport capacity and (2) exhaustion of supply from upstream and downcutting, maintaining high sediment transport rates through recruitment of material in the valley deposit. With a catchment area of only 3 km2, the upper river has transferred more than 4.2×106 m3 of coarse-grained material in 9 storm events of relatively modest intensity. This sequence of surveys provides an unprecedented picture of dramatic changes to a steepland river system in the aggradation/degradation cycle, which are very seldom captured owing to both the remoteness of such sites and the relative rarity of such events. A temporal picture of the valley sediment budget demonstrates the remarkable capacity of alpine systems to absorb disturbance through storage in the upper reaches, modulating the timing and the sedimentary character of materials being transferred to the reaches downstream. The case study highlights the utility of repeat LiDAR surveys for large-scale process studies and provides insights for assessing residence times of major landslide deliveries following large earthquake events.
Defining the composition of the deep mantle and the primordial He inventory of the Afar plume
Authors: Stuart Finlay , Balci Ugur , Barrat Jean-Alix
Published: March 2021

Basaltic rocks generated by upwelling mantle plumes display a range of trace element and isotope compositions indicative of strong heterogeneity in deep material brought to Earth surface.  Helium isotopes are an unrivalled tracer of the deep mantle in plume-derived basalts.  It is frequently difficult to identify the composition of the deep mantle component as He isotopes rarely correlate with incompatible trace element and radiogenic isotope tracers. It is supposed that this is due to the high He concentration of the deep mantle compared to degassed/enriched mantle reservoirs dominating the He in mixtures, although this is far from widely accepted.  The modern Afar plume is natural laboratory for testing the prevailing paradigm.

The 3He/4He of basalt glasses from 26°N to 11°N along the Red Sea spreading axis increases systematically from 7.9 to 15 Ra. Strong along-rift relationships between 3He/4He and incompatible trace element ratios are consistent with a binary mixture between moderately enriched shallow asthenospheric mantle in the north and plume mantle evident in basalts from the Gulf of Tadjoura, Djibouti (the Ramad enriched component of Barrat et al. 1990).  The high-3He/4He basalts have trace element-isotopic compositions that are similar, but not identical, to the high 3He/4He (22 Ra) high Ti (HT2) flood basalts erupted during the initial phase of the Afar plume volcanism (Rogers et al. in press). This suggests that the deep mantle component in the modern Afar plume has a HIMU-like composition. From the hyperbolic 3He/4He-K/Th-Rb/La mixing relationships we determine that the upwelling deep mantle has 3-5 times higher He concentration than the asthenosphere mantle beneath the northern Red Sea.

Barrat et al. 1990.  Earth and Planetary Science Letters 101, 233-247.
Human and biophysical influence on fire ignition likelihood in protected areas as a function of fire size in west-central Spain
Authors: Arellano-del-Verbo Gonzalo , R. Urbieta Itziar , Moreno José M.
Published: March 2021

Forest fires affect Mediterranean ecosystem, often affecting protected areas. Because these normally harbour vegetation in a better conservation state and more continuous in space, it is important to determine how they burn compared to other areas. In this study we modelled fire ignition likelihood in west-central Spain as a function of biophysical and anthropogenic variables, with a special focus on natural areas that have been recently protected by the EU Natura 2000 Network. During the 2001-2015 period more than 9000 ignitions (≥1ha) were recorded in the Spanish National Forest Fire Statistics (EGIF). We characterized each ignition point with a series of biophysical (topography, radiation and land use-land cover [LULC] types) and anthropogenic (distance to highways and roads, population density, farm density, protected areas, and forest interfaces [WUI, WAI, WGI]) variables. We built and compared statistical models of fire likelihood using the MaxEnt software for three different fire sizes: ≥ 1ha (n=9089), ≥ 10ha (n=1927) and ≥ 100ha (n=292) using a 50% random test percentage in each model. Models for the likelihood of having small and medium fires (≥ 1ha and ≥ 10ha) showed the lowest performance (AUC = 0.65, AUC = 0.73). Biophysical variables barely showed importance in explaining fire activity (except for radiation). Conversely, anthropic variables like distance to roads and settlements, population density, and farm density were important predictors. Models for fires ≥ 100ha showed the best performance (AUC = 0.84). Large fire likelihood was mainly explained by biophysical variables like radiation, elevation and some LULC types (e.g., grasslands, agrarian, shrublands, and oak forests), compared to those of anthropic origin. Protected areas showed the greatest contribution to explain the ignitions of large fires. Our models highlight the different relations of biophysical and anthropogenic variables with the likelihood of fire ignitions according to their final size. 
Improving the representation of cropland sites in the Community Land Model (CLM) version 5.0
Authors: Boas Theresa , Bogena Heye , Grünwald Thomas , Heinesch Bernard , Ryu Dongryeol , Schmidt Marius , Vereecken Harry , Western Andrew , Hendricks-Franssen Harrie-Jan
Published: March 2021

The incorporation of a comprehensive crop module in land surface models offers the possibility to study the effect of agricultural land use and land management changes on the terrestrial water, energy and biogeochemical cycles. It may help to improve the simulation of biogeophysical and biogeochemical processes on regional and global scales in the framework of climate and land use change. In this study, the performance of the crop module of the Community Land Model version 5 (CLM5) was evaluated at point scale with site specific field data focussing on the simulation of seasonal and inter-annual variations in crop growth, planting and harvesting cycles, and crop yields as well as water, energy and carbon fluxes. In order to better represent agricultural sites, the model was modified by (1) implementing the winter wheat subroutines after Lu et al. (2017) in CLM5; (2) implementing plant specific parameters for sugar beet, potatoes and winter wheat, thereby adding the two crop functional types (CFT) for sugar beet and potatoes to the list of actively managed crops in CLM5; (3) introducing a cover cropping subroutine that allows multiple crop types on the same column within one year. The latter modification allows the simulation of cropping during winter months before usual cash crop planting begins in spring, which is an agricultural management technique with a long history that is regaining popularity to reduce erosion and improve soil health and carbon storage and is commonly used in the regions evaluated in this study. We compared simulation results with field data and found that both the new crop specific parameterization, as well as the winter wheat subroutines, led to a significant simulation improvement in terms of energy fluxes (RMSE reduction for latent and sensible heat by up to 57 % and 59 %, respectively), leaf area index (LAI), net ecosystem exchange and crop yield (up to 87 % improvement in winter wheat yield prediction) compared with default model results. The cover cropping subroutine yielded a substantial improvement in representation of field conditions after harvest of the main cash crop (winter season) in terms of LAI magnitudes and seasonal cycle of LAI, and latent heat flux (reduction of winter time RMSE for latent heat flux by 42 %). Our modifications significantly improved model simulations and should therefore be applied in future studies with CLM5 to improve regional yield predictions and to better understand large-scale impacts of agricultural management on carbon, water and energy fluxes.
Maastrichtian-Rupelian paleoclimates in the southwest Pacific realm – a critical evaluation of biomarker paleothermometry and dinoflagellate cyst paleoecology at Ocean Drilling Program Site 1172
Authors: Bijl Peter , Frieling Joost , Cramwinckel Marlow Julius , Boschman Christine , Sluijs Appy , Peterse Francien
Published: March 2021

Sea surface temperature (SST) reconstructions based on isoprenoid glycerol dialkyl glycerol tetraether (isoGDGT) distributions from the Eocene southwest (sw) Pacific Ocean are unequivocally warmer than can be reconciled with state-of-the-art fully coupled climate models. However, the SST signal preserved in sedimentary archives can be obscured by contributions of additional isoGDGT sources. We here use current proxy insights to assess the reliability of the isoGDGT-based SST signal in 69 newly analysed and 242 re-analysed samples covering the Maastrichtian to Oligocene from ODP Site 1172 (East Tasman Plateau, Australia) following state-of-the-art chromatographic techniques. We then reinterpret the record in context of paleo-environmental and paleoclimatologic reconstructions based on dinoflagellate cysts. Our ~130 kyr-resolution SST record reaffirms previous reconstructions of anomalous warmth in the early Eocene sw Pacific and remarkably cool conditions during the mid-Paleocene. Dinocyst diversity and temperature-sensitive taxa show a strong response to the local SST evolution, supporting the robustness of the marine biomarker record.  In addition, the long-term isoGDGT and dinocyst records provide further support for an apparent temperature control on compositional changes of branched glycerol monoalkyl glycerol tetraethers (brGMGTs), recorded in the same samples.Soil-derived branched GDGTs (brGDGTs) stored in the same sediments are used to reconstruct mean annual air temperature (MAAT) of the nearby land through the MBT’5me proxy. General trends in SST and MAAT are similar, except for 1) an enigmatic absence of MAAT rise during the Paleocene-Eocene Thermal Maximum and Middle Eocene Climatic Optimum, and 2) a subdued middle–late Eocene MAAT cooling relative to SST. Both dinocyst assemblages and brGDGT indices (the isomerization index) suggest a mid-shelf depositional environment with strong river-runoff during the Paleocene-early Eocene, becoming more open marine thereafter. This trend reflects gradual drying and more seasonal precipitation regime in the northward drifting Australian hinterland. The overall correlation between dinocyst assemblages, biodiversity and SST changes suggests that temperature and associated environmental changes exert a strong influence on the surface-water ecosystem.