bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of SVEN model to estimate evapotranspiration on a coffee plantation using MODIS and Sentinel products.
Authors: Durán-Quesada Ana María , Pateromichelaki Ioanna , García Mónica , Wang Sheng , Serra Yolande , Gutiérrez Marco , Chinchilla Cristina
Published: March 2021

Warming conditions represent a threat to food security and livelihood in countries in which agriculture is an important share of the national income. Central America is regarded as a climate change hotspot where significant changes in temperature and rainfall have been projected. Coffee is one of the most traditional crops in the area, with Costa Rican coffee recognized worldwide for its quality. However, increasing temperatures and rainfall extremes will likely compromise coffee plantations. A similar challenge has already been faced by farmers on interannual time scales related to the El Niño-Southern Oscillation phenomena, which is associated with yield disruptions and the spread of the coffee rust. A better understanding of the weather and climate dependency of coffee crops is needed to develop water use efficiency strategies for farms. To this end, the present study centers on the integration of long-term meteorological records and a set of measurements that cover the soil-plant-atmosphere continuum. Surface fluxes derived using the eddy covariance technique and the deployment of soil moisture sensors are combined to evaluate the performance of the Soil Vegetation Energy TraNsfer (SVEN) model. One year of micrometeorological and soil measurements in a sun-exposed coffee plantation is used to assess the skills of the SVEN model using a scheme based on MODIS and Sentinel derived products. The aim of this work is to evaluate the skills of the SVEN model to reproduce the intraseasonal seasonal and diurnal variability of evapotranspiration. Given the size of Costa Rica and the scale of the crops, satellite products are often considered of limited use. Nevertheless, given the strong need, the goal of this project is to provide a detailed evaluation of the use of these products in models and support strategies that could expand the use of satellite retrievals in areas currently considered marginal.
Assessment of GloFAS ensemble flood forecast for the Brahmaputra basin: skilful lead-times to predict monsoon floods for early action in Bangladesh
Authors: Hossain Sazzad , Cloke Hannah , Ficchì Andrea , Prudhomme Christel , Bhuyan Arifuzzaman , Stephens Elisabeth
Published: March 2021

Flood is a frequent natural hazard in the Brahmaputra basin in Bangladesh during the South Asian summer monsoon between June to September. When will flooding start during monsoon and how long it will last are two important questions that forecasters need to answer. Predicting flood timing and duration with a sufficient lead-time is challenging for forecasters due to strong intraseasonal variation of floods within a monsoon.

The GloFAS forecasting system is run by ECMWF as part of the Copernicus Emergency Management Service and provides operational extended-range ensemble flood forecast with 30 days lead-time for the major river basins in the world. In this study, we evaluated GloFAS reforecasts for the Brahmaputra basin in Bangladesh for the period 1997–2019 at different lead-times against observed stream gauge and ECMWF ERA5 reanalysis river discharge data. We used various probabilistic forecast verification metrics, such as Relative Operating Characteristic (ROC), False Alarm Ratio (FAR), and Probability of Detection (POD), to study how forecast skill varies over different lead-times. We also assessed the skilful lead-times of the GloFAS forecast to predict flood timing and duration during the monsoon. These scores were calculated considering relevant flood threshold levels and action-based parameters, such as Action Lifetime, based on user needs in Bangladesh. The GloFAS forecast case study for the recent 2020 monsoon floods in the Brahmaputra basin shows that the onset of flood events was successfully predicted with a lead-time of 15 days. These forecasts were disseminated among the different stakeholders, including humanitarian agencies, flood and disaster management organisations, to inform forecast-based actions, such as evacuation of vulnerable people to safer places ahead of flood events. Our study demonstrates that GloFAS ability to predict monsoon floods in terms of timing and duration can improve national flood forecasting capabilities providing sufficient lead-time for early actions in Bangladesh. The study will help forecasters as well as users to understand forecast skill and associated uncertainty in probabilistic forecasts to predict flood events in Bangladesh.

 

 

 
Catastrophic landslide affected by topography: a case study in Guizhou, China
Authors: Guo Jian
Published: March 2021

In mountainous areas, large-scale landslides usually cause serious disasters. A large number of studies have found that complex terrain may affect the landslides dynamic, which may be one of the significant factors in catastrophic events. However, the mechanism is rarely explored. On July 23, 2019, a large-scale landslide occurred in Jichang town, Shuicheng County, Liupanshui City, Guizhou Province in China. The landslide, which moved along two gullies, resulted in strong punching-shear, induced scarping on vegetation and large destruction of houses and finally formed a deposit with a volume of 2×106 m3. This research aims to understand the effect of topography on landslide kinematics. To achieve this aim, a detailed field investigation was first carried out with an unmanned aerial vehicle (UAV) aerial photography survey, resident interviews, and field sampling. The rainfall analysis indicate the effective rainfall within seven days before landslides was 70.14 mm which exceeded the rainfall threshold of 54.3 mm in this region, which finally triggered the landslide. Traditional soil mechanics tests were then performed to identify the soil properties of the source material. Combined with numerical simulation using the nonlinear shallow water equation, the whole process of landslides was divided into four stages: instability stage, acceleration stage, transformation stage and impact and accumulation stage. The simulations results show the landslide block slid with a low velocity of 8 m/s for about 100 m. Then, Froude number of landslide increase from 2 to 3 when passing the high and steep terrain, indicating that landslide change to inertial dominated with potential same Froude behavior of classic debris flow. The rupture mass slid with the peak velocity of 23 m/s and diverged in two gullies and ran out for about 600 m. The maximum velocity is 23 m/s in east gully while only 15 m/s in west gully. Compared with deep and incised valleys in west, shallow and straight valley in east decrease the deposit depth, further increase the velocity of landslide material with increased runout distance. This research may provide a fast flow path of back analyzing geo-hazards on complex terrain and serve as a basis for future research on long runout landslides. 
An Approach for Open and Reproducible Hydrological Modeling using Sciunit and HydroShare
Authors: Choi YoungDon , Goodall Jonathan , Ahmad Raza , Malik Tanu , Tarboton David
Published: March 2021

It is widely acknowledged that the reproducibility of published computational results is critical to advancing science. Creating reproducible computational workflows, however, is burdensome and requires significant work to share the complete package that efficiently encapsulates all required data and software. Computational hydrology is one field that has seen rapid advancements through fast-evolving technologies for supporting increasingly complex computational hydrologic modeling and analysis. This growing model complexity, along with rapidly evolving underlying software technologies, makes the options and approaches for achieving computational reproducibility extremely challenging to settle. We argue that the technologies needed to achieve open and reproducible hydrological modeling can be grouped into three general categories: 1) data (and metadata) sharing, 2) containerizing computational environments, and 3) capturing and executing modeling workflows. While a growing set of science gateways and virtual research environments have been created to support one or more of these technologies to improve reproducibility, the integration and interoperability across all three needs are still lacking, making end-to-end systems still out of reach. The objective of this research is to advance such an end-to-end solution that can support open and reproducible hydrological modeling that effectively integrates data sharing, containerization, and workflow execution environments. Our approach emphasizes 1) well-documented modeling objects shared with meaningful metadata through the HydroShare open repository, 2) version control with efficient containerization using the Sciunit software, and 3) immutable, but flexible, computational environments to use newly developing software packages. A key to this work is advancing Sciunit, a tool for easily containerizing, sharing, and tracking deterministic computational applications, to minimally containerize reproducible hydrologic modeling workflow objects into the same container with version control capabilities. We present how to add new model input and modeling dependencies into the Sciunit container for flexibility and how to create Docker images through Sciunit containers for compatibility with popular containerization tools. In this presentation, we will emphasize both the underlying technological developments made possible through this research along with a user-centric case study showing the application of the technology from a hydrologic modeler’s perspective.
Integrated Spatial and Economic Analysis on Water Infrastructure Expansion Profitability and Affecting Climatic Factors within the Central Valley of California
Authors: Maskey Mahesh Lal , Li Liying , Fernandez-Bou Angel S. , Viers Joshua H. , Medellin-Azuara Josue
Published: March 2021

Climate signals have been consistently changing over the past century, together with increased population and human activities. Consequently, notable shifts in timing and magnitude of floods and drought and declining surface and subsurface water storage have been seriously posing effects on water supply and demand throughout the planet. Hence, it becomes relevant to understand the optimal water allocation to different water users such as agriculture, urban, environmental, and wildlife refuge and manage water infrastructure projects accordingly to support optimal water allocation. In the past, we have shown the successful application of the statewide hydro-economic model, also known as CALVIN (California Value Integrated Network)1,2, to minimize water allocation costs and optimize water utility under the policy, operational, and environmental constraints.

This study utilizes economic and water allocation output from the CALVIN model historical run (1921 to 2003; monthly scale), and it explores the opportunity cost of water storage and conveyance expansion in California (economic data based on 2050 projected water use3,4). This study performs a time series analysis on the marginal economic value of expansion to characterize the correlation between historical climatic factors with water allocation capacity extension to characterize how climate events such as droughts or floods can affect the profitability of water infrastructure expansion projects. The result provides useful information for statewide planners and decision-makers in setting coping strategies for the future under climate change conditions5,6. Additionally, this study uses the historical run expansion cost results to identify the most profitable water infrastructure expansion locations using spatial analysis. This study concentrates on agriculture and urban water demands from surface and groundwater sources and categorizes the water allocation over different water years dictated by the California Department of Water Resources (DWR). This study offers a holistic approach to elucidate responses of existing water supply-demand nexus, and the results will be useful for the Sustainable Groundwater Management Act (SGMA) of California.

References:

 
Formation and decay of a transpolar arc during a major magnetic storm onset
Authors: Pulkkinen Tuija , Hill Shannon , Al Shidi Qusai , Brenner Austin , Zou Shasha
Published: March 2021

We examine a transpolar arc that formed at the onset of a geomagnetic storm on 15 May 2005 just prior to the arrival of a magnetic cloud. The theta aurora was recorded over the southern hemisphere by the FUV-WIC camera onboard IMAGE satellite. While in most cases transpolar arcs decay as the IMF turns southward, this arc persisted for almost an hour into the cloud, with peak AL-activity below -1500 nT and Dst at the level of -100 nT.  We use the University of Michigan Space Weather Modeling Framework (SWMF) global geospace simulation to study the magnetotail, inner magnetosphere, and ionospheric conditions during the theta aurora to resolve the origin of the polar cap precipitation. At the time of formation of the theta aurora, the SWMF simulation results indicate a single-cell potential pattern, very low Region 2 currents, and slow inner magnetotail convection. A substorm onset took place as a result of IMF turning, re-creating and enhancing the two-cell convection pattern while the theta aurora persisted. The tail flows were a complex mixture of Earthward flows along the plasma sheet boundary layer and tailward flows at the tail center created by the substorm-associated near-tail reconnection. We analyze the ionospheric mapping of the Earthward flows and the effects of the global current systems on the large-scale auroral precipitation pattern.
Mining and the green energy transition: an analysis exploring threats to biodiversity and conservation priorities
Authors: Sonter Laura
Published: March 2021

Switching from fossil fuels to renewable sources of energy is needed to achieve net zero emissions this century and safeguard the climate conditions underpinning natural systems and human society. However, renewable energies are material intensive and so growing the supply of wind, solar and hydropower will increase demand for the minerals these technologies require. Some energy transition minerals, such as copper, nickel, cobalt and lithium, have deposits that coincide with biodiverse places, where mining may create new, or exacerbate existing (including climate change driven), threats to biodiversity. In the talk, I will present an analysis exploring the spatial correlation between mineral resources, sites valued for biodiversity (protected areas, key biodiversity areas) and areas containing habitat for threatened species. Results suggest that a green energy transition will create new mining threats to biodiversity, many of which are not addressed by current conservation plans and policies. I will outline the tools needed to better understand the impacts of extracting energy transition minerals, and discuss the contexts in which ecological compensation approaches may be appropriate to achieve No Net Loss of biodiversity.
Dynamic Rupture Scenarios of Large Earthquakes on the Rodgers Creek-Hayward-Calaveras-Northern Calaveras Fault System, California
Authors: Harris Ruth , Barall Michael , Ponce David , Moore Diane , Graymer Russell , Lockner David , Morrow Carolyn , Funning Gareth , Kyriakopoulos Christos , Eberhart-Phillips Donna
Published: March 2021

The Rodgers Creek-Hayward-Calaveras-Northern Calaveras fault system in California dominates the hazard posed by active faults in the San Francisco Bay Area. Given that this fault system runs through a densely populated area, a large earthquake in this region is likely to affect millions of people. This study produced scenarios of large earthquakes in this fault system, using spontaneous (dynamic) rupture simulations. These types of physics-based computational simulations require information about the 3D fault geometry, physical rock properties, fault friction, and initial stress conditions. In terms of fault geometry, the well-connected multi-fault system includes the Hayward fault, at its southern end the Central and Northern Calaveras faults, and at its northern end the Rodgers Creek fault. Geodetic investigations of the fault system’s slip-rate pattern provide images of where the fault surfaces at depth are creeping or locked interseismically, and this helped us choose appropriate initial stress conditions for our simulations. A 3D geologic model of the fault system provides the 3D rock units and fault structure at depth, while field samples from rocks collected at Earth’s surface provide frictional parameters. We used this suite of information to investigate the behavior of large earthquake ruptures nucleating at various positions along this partially creeping fault system. We found that large earthquakes starting on the Hayward fault or on the Rodgers Creek fault may be slowed, stopped, or unaffected in their progress, depending on how much energy is released by the creeping regions of the Hayward and Central Calaveras faults during the time between large earthquakes. Large earthquakes starting on either the Hayward fault or the Rodgers Creek faults will likely not rupture the Northern Calaveras fault, and large earthquakes starting on either the Northern Calaveras fault or the Central Calaveras fault will likely remain confined to those fault segments.
Assessing plant-microbe interactions in the rhizosphere using spatially resolved proteomics 
Authors: Moran James , Lin Vivian , Zhu Ying , Thompson Allison , Purvine Samuel , Tolic Nikola , Rosnow Joshua , Lipton Mary
Published: March 2021

Extensive spatial variability combined with analytical challenges associated with soil sampling complicate efforts to elucidate plant-microbe interactions within the rhizosphere, changes in these relationships over time, and the impacts of shifting microenvironmental conditions on microbial community membership and activity. Proteomics analysis of root or soil samples can provide insights to the taxonomy and functional capability of microbial populations and be used to augment various genomic and imaging techniques. Historically, however, proteomics relies on bulk level sampling by removing rhizosphere over relatively large lengths of root surface and is, therefore, neither spatially specific nor non-destructive. We are employing spatially resolved, non-destructive harvesting of mobile proteins onto a membrane to enable both two-dimensional protein mapping and proteomic analysis within rhizosphere while preserving the sample for either timeseries measurements or complementary, destructive techniques.

We are using rhizoboxes planted with switchgrass (variety Cave-in-rock) and constructed with natural soil (Kellogg Biological Station, Hickory Corners, Michigan, USA) to develop the approach. We are coupling membrane extraction with specialized sample digestion, purification, and analysis to enable proteomic interpretation. Through its non-destructive nature, this approach permits timeseries analyses for tracking specific taxa and, in some cases, functions associated with rhizosphere processes before and after a system perturbation or over plant growth phases during a growing season. The method’s high sensitivity enables spatial analysis at the up to two-millimeter diameter scale along the rhizobox sampling plane and samples can be manually selected based on proximity to specific root structure, metabolic hotspots, or other parameters of choice. We are using this analysis to track statistically significant shifts in plant and microbe contributions to rhizosphere proteome associated with roots at different growth stages. We are also linking this approach to a 13C tracer to identify specific taxonomic groups having the closest metabolic association with a host plant to identify shifts in plant-microbe interactions associated with nutrient availability. For instance, we are using a split root rhizobox approach to monitor the plasticity of plant-microbe C exchange associated with P availability. Combined, the spatial and 13C tracer components of this proteomic technique can help illuminate understanding of the complex inter-kingdom interactions within the rhizosphere and the implications these interactions have on driving C cycling and plant performance.
Dynamics of arc-continent collision: the role of crustal-mantle dynamics on controlling the spatio-temporal evolution of stress 
Authors: Rodriguez Corcho Andres Felipe , Morón Sara , Farrington Rebecca , Beucher Romain , Moresi Louis , Montes Camilo
Published: March 2021

Arc-continent collision is the process by which intra-oceanic arc crust is accreted to continental margins and the most important mechanism that enables the growth of the continental crust since Phanerozoic times. We use numerical visco-plastic mechanical models to explore: (i) the role of lithospheric-mantle dynamics in controlling the spatio-temporal evolution of stress in arc-continent collision settings, and (ii) the role of density contrasts in the evolution of the stress regime. We performed a series of simulations only varying the thickness of the arc based on natural examples as the arc thickness controls the buoyancy of intra-oceanic arcs. Therefore, we investigated a range of density contrasts between the arc and the continental plate. Modelling results show that arc-continent collision can evolve into two contrasting scenarios: (i) slab-anchoring and arc transference in dense arcs where the density contrast between the arc and the adjacent continental lithosphere is above -3% (15-31 km in thickness); and (ii) slab break-off in buoyant arcs where the density contrast between the arc and the adjacent continental lithosphere is below -3% (32-35 km in thickness). We conclude that the large-scale mantle return flow emerged from slab-anchoring facilitates the simultaneous occurrence of compression and extension in the margin by enhancing: (i) compression and lithospheric thickening of the buoyant intra-oceanic arc crust; and (ii) the density contrast between the accreted arc and the continental margin that triggers the release of a gravitational flow. In the particular case of buoyant arcs, the compressional body force applied by the deformed arc to the subducting plate drives its passive retreat. The results of our numerical modelling highlight the importance of the role of lithospheric-mantle dynamics on controlling the spatio-temporal evolution of stress.
An objective separation of rainfall classes in the high tropical Andes by using a clustering analysis.
Authors: Urgilés Gabriela , Célleri Rolando , Trachte Katja , Bendix Jörg , Orellana-Alvear Johanna
Published: March 2021

Information about the temporal rainfall variability at high-resolution is scarce, especially in regions with complex topography as the Tropical Andes, and this hinders the study rainfall dynamics. The identification of rainfall types is usually determined using thresholds of some rainfall characteristics as rain rate and velocity. Nevertheless, these thresholds are identified for a specific study area and thus they cannot be extrapolated to other places to identify rainfall classes. Thus, the aim of this study is to investigate rainfall-event classes based on a clustering approach by using the k-means algorithm. The clustering analysis is used to group objects (i.e., rainfall-events) based on its characteristics (e.g., duration, intensity, drop size distribution, melting layer identification). This study was carried out using data retrieved from a vertically pointing Micro Rain Radar (MRR) and a laser disdrometer. The instruments were located in the tropical Andes, at 2600 m a.s.l., in the city of Cuenca, Ecuador.  Three years of data were available for the study. Firstly, the rainfall events were selected by using the criteria: minimum inter-event, minimum total accumulation and minimum duration. Then, by using the k-means algorithm, two principal rainfall classes were identified in the study area. These rainfall classes (i.e., convective, stratiform) showed marked differences in their rainfall characteristics. Besides, a third rainfall class (mixed class) was identified as a subclass of the stratiform class. The stratiform class was more common during the year in the study area. Also, short duration rainfall events (less than 70 min) were dominant. Furthermore, the melting layer characteristic – that is used to determine rainfall classes – did not influence the rainfall class identification using the clustering analysis, especially in two classes; thus, its prior study is not necessary, and this makes the clustering analysis highly beneficial. Finally, this clustering analysis ensured an objective separation of rainfall classes in the tropical high Andes. This rainfall classification provided new insights about the rainfall dynamics in this tropical mountain area.
Identifying global hotspots of plastic waste accumulation along river networks
Authors: Gomez-Velez Jesus , Krause Stefan
Published: March 2021

Global plastic pollution is affecting ecosystems and human health globally. Proposing solutions and coping strategies for this threat requires a clear understanding of the processes controlling the fate and transport of mismanaged plastics at multiple scales, going from watersheds to regions and even continents. River corridors are the primary conveyor and trap for mismanaged plastic produced within the landscape and eventually released to the ocean. New approaches that apply technological sensing innovations for monitoring plastic waste in aquatic environments can improve observations and plastic waste datasets globally. However, our understanding of when, where, and how to target monitoring is limited, reducing the benefit gained. There is therefore a critical demand for predictions of hotspots (as well as hot moments) of plastic accumulation along river networks globally, in order to optimize observational capacity.     

Here, we present a new global flow and transport model for plastic waste in riverine environments. Our model predicts that only a small fraction (roughly 2.5%) of the global mismanaged plastic that entered rivers since the 1950s has been delivered to the ocean by 2020, with an overwhelming majority sequestered in freshwater ecosystems. Furthermore, we predict the patterns of mismanaged plastic accumulation and its residence time depend on (i) the topology and geometry of the river network, (ii) the relative location of plastic sources, and (ii) the relative location and trapping efficiency of flow regulation structures, primarily large dams. Our results highlight the role of rivers as major sinks for plastic waste and the need for targeted remedial strategies that consider the structure of the river network and anthropogenic regulation when proposing intervention measures and sampling efforts.
Spatiotemporal and Synchronous Monitoring of Drought in the Dry Corridor of Central America
Authors: Sanchez Hernandez Karel Aldrin , Corzo Perez Gerald Augusto , Santos Granados German Ricardo
Published: March 2021

Drought is often conceptualised as an extreme weather event generated by anomalies in water resources availabilities. Understanding the behaviour and spatiotemporal distribution of drought events has become very important due to the possible teleconnections of drought propagation patterns. This understanding and if is possible representation of teleconnections between patterns could lead to better prediction and management of extreme events.
This study develops a methodology to monitor spatiotemporal drought events in the dry corridor of Central America using the drought index SPI and SPEI for the period 1981 to 2020.
This methodology consists of five stages. 1) collection and quality validation of the data sets used. 2) ERA5 and Observation datasets allow calibrating the precipitation and temperature values from historical gauge measurements. 3) Then, by the estimation and trend analysis of the drought index in different time scales (3, 6, 12 months) an initial baseline is defined. 4) Spatiotemporal association algorithms (based on computer vision) are used to characterise and monitoring the most extensive drought events. For this, the extreme and severe events (DI values below -1) threshold is estimated. 5)  Synchronic Integration between temporal patterns and spatial propagation is carried out to evaluate possible interactions or connections of drought events along the dry corridor of Central America. These results provide valuable information to evaluate the impacts on different sectors threatened by drought throughout the territory. This work presents preliminary results of an extended project looking at the dry corridor in Central America. 
Effects of natural streambed sediment on the riverbed exchange flows and microbial respiration
Authors: Chen Yunxiang , Bao Jie , Li Bing , Liu Xiaofeng , DiBiase Roman , Scheibe Timothy
Published: March 2021

Exchange flows at the water-sediment interface control river water quality and carbon cycling through microbial respiration. However, accurate quantification of these exchange flows and microbial respiration is still challenging in field surveys due in part to the dynamic turbulence generated by streambed topography. Using a framework that combines Structure-from-Motion (SfM) photogrammetry with a fully-coupled surface-subsurface computational fluid dynamics (CFD) model, this work studies the effects of streambed sediment structure on riverbed turbulence and its impact on exchange flows and microbial respiration. Specifically, the SfM photogrammetry is first applied to obtain mm- to cm-scale resolution riverbed topography over a meter scale domain at four sites; these high-resolution riverbed topography data are then used to generate meshes for use in hyporheicFoam, a fully coupled surface-subsurface model developed in OpenFOAM. Simulated time series of water depth and average flow velocity from a previously-developed 30-kilometer scale CFD model will be used to set the water depth and mean flow velocity conditions for high-resolution CFD models of the SfM-characterized locations. The modeling results will be used to investigate the dependence of riverbed exchange flows, concentration gradients, and the concentration profile from the water surface to riverbed on water depth, mean velocity, roughness size, sediment distribution, bed porosity, and subsurface permeability. The relative importance of flow advection, turbulence dispersion, and microbial reaction in both streambed and surface water will also be evaluated.
Coupled evolution of supercontinents and lower mantle structure
Authors: Cao Xianzhi , Flament Nicolas , Bodur Ömer , Müller Dietmar
Published: March 2021

The relationships between plate motions and basal mantle structure remain poorly understood, with some models implying that the basal mantle structure has remained stable over time, while others suggest that it could be shaped by the aggregation and dispersal of supercontinents. Here we investigate the plate-basal mantle relationship through 1) building a series of end-member plate tectonic models over one billion years, and 2) creating mantle flow models assimilated by those plate models. To achieve that, we build synthetic plate tectonic models dating from 1 Ga to 250 Ma that we connect to an existing palaeogeographical plate reconstruction from 250 Ma to create a relative plate motion model for the last 1 Gyr, in which supercontinent breakup and reassembly occur via introversion. We consider three distinct reference frames that result in different net lithospheric rotation. We find that the flow models predict a dominant degree-2 lower mantle structure most of the time and that they are in first-order agreement (~70% spatial match) with tomographic models. Model thermochemical structures at the base of the mantle may split into smaller structures when slabs sink onto them, and smaller basal structures may merge into larger ones as a result of slab pushing. The basal thermochemical structure under the superocean is large and continuous, whereas the basal thermochemical structure under the supercontinent is smaller and progressively assembles during and shortly after supercontinent assembly. In the models, plumes also develop preferentially along the edge of the basal thermochemical structures and tend to migrate towards the interior of basal structures over time as they interact with the slabs. Lone plumes can also form away from the main thermochemical structures, often within a small network of sinking slabs. Lone plumes may migrate between basal structures. We analyse the relationship between imposed tectonic velocities and deep mantle flow, and find that at spherical harmonic degree 2, the maxima of lower mantle radial flow and temperature follow the motion path of the maxima of surface divergence. It may take ~160-240 Myr for lower mantle structure to reflect plate motion changes when the lower mantle is reorganised by slabs sinking onto basal thermochemical structures, and/or when slabs stagnate in the transition zone before sinking to the lower mantle. Basal thermochemical structures move at less than 0.6 °/Myr in our models with a temporal average of 0.16 °/Myr when there is no net lithospheric rotation, and between 0.20-0.23 °/Myr when net lithospheric rotation exists and is induced to the lower mantle. Our results suggest that basal thermochemical structures are not stationary, but rather linked to global plate motions and plate boundary reconfigurations, reflecting the dynamic nature of the co-evolving plate-mantle system.
Fostering International Collaboration Through a Unified Verification, Validation, and Diagnostics Framework - METplus 
Authors: Jensen Tara , Mittermaier Marion , Kucera Paul , Brown Barbara
Published: March 2021

Verification and validation activities are critical for the success of modeling and prediction efforts at organizations around the world.  Having reproducible results via a consistent framework is equally important for model developers and users alike.  The Model Evaluation Tools (MET) was developed over a decade ago and expanded to the METplus framework with a view towards providing a consistent platform delivering reproducible results.   

The METplus system is an umbrella verification, validation and diagnostic framework for use by thousands of users from both US and international organizations.  These tools are designed to be highly flexible to allow for quick adaption to meet additional evaluation and diagnostic needs.  A suite of python wrappers have been implemented to facilitate a quick set-up and implementation of the system, and to enhance the pre-existing plotting capabilities.  Recently, several organizations within the National Oceanic and Atmospheric Adminstration (NOAA), the United States Department of Defense (DOD), and international partnerships such as Unified Model (UM) Partnership led by the Met Office have adopted the tools for their use both operationally and for research purposes.  Many of these organizations are also now contributing to METplus development, leading to a more robust and dynamic framework for the entire earth system modeling community to use.

This presentation will provide an update on the current status of METplus and how it is being used in across multiple scales and applications.  It will highlight examples of METplus applied to verification and validation efforts throughout the international community to address a range of temporal (hourly forecasts to subseasonal-to-seasonal) and spatial scales (convection allowing to mesoscale, regional to global, tropical to cryosphere to space).
The influence of backstop geometry in the structural style of the Eastern Cordillera of Colombia: A sandbox modeling approach 
Authors: Conde Carvajal Camilo Andrés , Riascos Rodríguez Cristhian Bolívar , Avila Paez Michael Andres , Kammer Andreas
Published: March 2021

Among the foreland belts of the Andean mountain system, the Eastern Cordillera of Colombia (EC) represents a unique example of an isolated, bi-vergent mountain belt. In contrast, to block tectonics of broken foreland basins, it displays a ductile deformation style which involves two mountain fronts with a structural relief of the order of 10 km. Internal parts of the EC have been shortened by buckling at high and a homogeneously strained basement at deeper structural levels. These deformation patterns likely attest to conditions of a thermally weakened backarc setting. Two opposed scenarios have been postulated for its surface uplift and consequent exhumation: 1) an E-migrating deformation front and the formation of progressively forward breaking faults; and 2) the pop-up of a weak crustal welt enclosed by strong foreland blocks. In this latter setting, a synchronous early formation of marginal mountain fronts and a late-stage surface uplift of a central domain may be anticipated. These two constellations compare, in terms of a contrasting model setup, to a foreland migrating orogenic wedge or a relatively stable, doubly vergent wedge formed above a structural discontinuity or rheologic boundaries that acted as sites for the nucleation of the marginal faults.

In this contribution, we opt to examine the “boundary” conditions for the development of a doubly vergent wedge formed at the tip line of a rigid tapering backstop, that simulates a rigid foreland block. With respect to the shape of this backstop, we examine the effects of tip angles less than the angle of internal friction (<30°) and find, that at a low tip angle of 10° the pop-up evolves above a forward-breaking principal kink-band with the synchronous formation of a sequence of conjugate back-kinks that cut into the sand pack, as it is pushed toward the backstop. At a moderate tip angle of 20o the forward-breaking kink-band is slightly steeper than the backstop and gives rise to a frontal fold with an overturned limb. This latter geometrical configuration loosely compares to the structural relations of a structural section through the high plains of Bogotá, where the eastern mountain front defines a strongly deformed antiform, that is juxtaposed against an undeformed margin of the adjacent Guyana shield.
Naturally rainfall-induced changes in runoff-associated nitrogen and phosphorus losses in purple soil area: roles of land disturbance and plot length
Authors: Liang Ke , He Binghui
Published: March 2021

Severe soil erosion occurs in southwestern China owing to the large expanses of human disturbance and sloping land. This field monitoring study was conducted during the rainy season to record the rainfall events, runoff, sediment yield, nitrogen, and phosphorous loss in 20-, 40-, and 60-m plots under conditions of artificial disturbance or natural restoration on a 15° slope in the purple soil area of southwestern China. The concentrations and loss amounts of total nitrogen (TN), total dissolved nitrogen (TDN), ammonium-nitrogen (NH4-N) and nitrate-nitrogen (NO3-N), total phosphorus (TP), total dissolved phosphorus (TDP) and orthophosphate (PO4-P) were comparatively determined. The highest N concentration was observed in long duration and soft rainfall events across all plots. The highest P concentration in artificial disturbed plots was found in long duration and intensive rainfall events while it was recordeds for measured variables were dominantly recorded under the long duration and lowest soft rainfall events in naturally restored plots intensity., while The the highest loss amounts for N and P in different forms for these variablesalmostmostly appeared under high rainfall intensity. Land disturbances differed orthophosphate PO4-P concentration in 20--m plot and and loss amounts of of measured variables N and P with different forms across in all plots. Plot lengths differed total dissolved phosphorus TDP concentration in natural restored plot and loss amounts of total dissolved nitrogenTDN and orthophosphate PO4-P in artificially disturbed plots. Naturally restoration reduced loss amounts of total nitrogen and total phosphorus by 69.4%62.14-79.05% and 79.28-83.43% TN, 68.8% TDN, 71.2% NH4-N, 74.3% NO3-N, 81.5% TP, 71.9% TDP and 70.0% PO4-P loss amounts comparedrelative to artificial disturbance, respectively. There were significant interrelationships among N and P concentrations in different forms in two land disturbance plots, while nitrate-NO3-nitrogenN concentration hadwas significantly negatively negative correlatedion with rainfall intensity and runoff rate in artificialally disturbanceed plots. Rainfall intensity was logarithmically correlated with TN, NO3-N concentrations in artificially disturbed plots and with NO3-N concentration in naturally restored plots. Runoff rate was logarithmically correlated with TN, TDN and NO3-N concentrations in artificially disturbed plots. Our results highlight the effects of land disturbance and plot length on nutrient losses in sloping land.
Temporal Variation Characteristics of Soil After Fire in A Post-fire Debris Flow Source Area
Authors: Lei Mingyu
Published: March 2021

The influence of forest fire on soil hydrology and mechanical effects promotes the occurrence of post-fire debris flow. However, the variation of soil properties with time has not been much studied. In order to determine the temporal variation characteristics of soil hydrology and mechanical effects after forest fires under different fire severities, and link them to the initiation of post-fire debris flows, a two-year continuous testing of samples from the source area of post-fire debris flows in Muli County, China, were investigated. Saturated direct shear test, saturated permeability experiment and scanning electron microscope experiments of undisturbed soil were carried out. The results showed that the burning of organic matter occurred, which reduced soil permeability sharply. In addition, high temperatures destroyed the structure of soil, causing the internal collapse of aggregates and reducing soil shear strength. While the herbaceous plants can quickly regenerate after fire, improving the hydrological and mechanical properties of soil, and reducing the frequency of post-fire debris flow. These results can evaluate the changes of soil physical and mechanical properties in short term after fire, and also explain the formation mechanism of post-fire debris flow. 
The Remarkable Generality of the Transient Storage Model with Residence Time Dependence: Temporal Moments.
Authors: Aghababaei Mohammad , Ginn Timothy , Carroll Kenneth , Gonzalez-Pinzon Ricardo , Tartakovsky Alex
Published: March 2021

Several distinct approaches to the one-dimensional modeling of river corridor transport at the macroscale have been developed as generalizations of the original Transient Storage Model (TSM).  We show that essentially all of them can be captured by simply restructuring the TSM so that the exchange coefficients are functions of residence time, because doing so converts the TSM to a general memory function form.  We use this generalized TSM approach to find novel closed-form expressions for the temporal moments of breakthrough curves resulting from river corridor tracer tests, when hyporheic zone exchange is governed by a memory function.  These expressions are useful because they can be used to test different hypotheses about the hyporheic zone residence time distribution based on analyses of the temporal moments of the tracer test breakthrough curves prior to detailed modeling work.  We demonstrate the application with a case study, and present extensions of the notion of making rate coefficients depend on residence time.
Projections of 21st century sea-level contribution from the retreat of Humboldt Glacier, North Greenland
Authors: Hillebrand Trevor , Hoffman Matthew , Perego Mauro , Price Stephen , Roat Abby , Howat Ian
Published: March 2021

Humboldt Glacier drains ~5% of the Greenland Ice Sheet and has retreated and accelerated since the late 1990s. The northern section of the terminus has retreated towards an overdeepening in the glacier bed that extends tens of kilometers towards the ice sheet interior, raising the possibility of a rapid increase in ice discharge and retreat in the near future. Here we investigate the potential 21st century sea-level contribution from Humboldt Glacier with the MPAS-Albany Land Ice (MALI) ice sheet model. First, we optimize the basal friction field using observations of surface velocity and ice surface elevation to obtain an initial condition for the year 2007. Next, we tune parameters for calving, basal friction, and submarine melt to match the observed retreat rates and surface velocity changes. We then simulate glacier evolution to 2100 under a range of climate forcings from the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6), using ocean temperatures from the MIROC5 Earth System Model, with surface mass balance and subglacial discharge from MAR3.9/MIROC5. Our simulations predict ~3.5 mm of sea-level rise from the retreat of Humboldt Glacier by 2100 for RCP8.5, and ~1 mm for RCP2.6. The results are insensitive to the choice of calving parameters for grounded ice, but a low stress threshold for calving from floating ice is necessary to initiate retreat. We find that a highly plastic basal friction law is required to reproduce the observed acceleration, but the choice of basal friction law does not have a large effect on the magnitude of sea-level contribution by 2100 because much of the ice is at present close to floatation in the areas that retreat most significantly. Instead, the majority of ice mass loss comes from increasingly negative surface mass balance. Preliminary results from experiments with a subglacial hydrology model suggest that the simple treatment of subglacial discharge used in our 21st century projections (as used in the ISMIP6-Greenland protocol) underestimates spatial variability of melting at the glacier front but gives a reasonable approximation of total melt. When compared to the recent ISMIP6 estimates of 60–140 mm sea-level rise from the entire Greenland Ice Sheet by 2100, our estimate of 3.5 mm from Humboldt Glacier indicates a significant but far from dominant contribution from this single large outlet.
Comparison of Spatial Interpolation Methods for Mapping Daily Air Temperature 
Authors: Sahoo Lasyamayee L , Dutta Subashisa
Published: March 2021

The sparsely distributed meteorological centers fails to provide enough information regarding spatial patterns. Even at places where dense meteorological stations are available, it is difficult to develop realistic gridded data due to the complex topography and climatic variability. Some of the climate as well as hydrological model require spatially continuous datasets as inputs. It is possible to obtain a continuous surface of raster datasets with the help of interpolation methods where each value is assigned based on surrounding values using specific mathematical formulas. For present study, various interpolation methods, like Inverse distance weighted, ordinary krigging, thin plate smoothing spline; has been compared for maximum and minimum temperature. Error in the interpolated data was analyzed by independent cross validation method, in which measurements like root mean square error (RMSE), mean squared relative error (MSRE), coefficient of determination (r2) and coefficient of efficiency (CE) were adopted for performance evaluation. Method with minimum error was chosen for developing the final map. It provides an effective way for mapping the meteorological variables in a topographically diverse region. In this case, an Indian state Odisha is chosen as study area. The state consists of 10 different agro-climatic zones and sees several weather systems across the year. The area suffers with floods, drought, heat waves and costal erosion almost every year with variable intensity. Strong heat waves in summer affect the human health, agriculture, construction efficiency and labour productivity. As three-fourth of the state is filled with mountains and high lands, monitoring network is sparsely distributed. Despite small latitudinal difference, temperature changes considerably with respect to both space and time. Here interpolation method plays a vital role to avoid uncertainty in modelling. Based on the generated maps, vulnerable areas on the basis of maximum temperature in summer and minimum temperature in winter is identified. Several indicators and vulnerability indices has been used.