bluuebunny/crossref_metadata_2025 huggingface dataset:
SIT4ME project: Up-scaling seismic methods for mineral exploration in the Zinkgruvan mining area, Sweden
Authors: Gil Alba , Malehmir Alireza , Buske Stefan , Alcalde Juan , Ayarza Puy , Martínez Yesenia , Lindskog Louise , Spicer Bill , Carbonell Ramon , Orlowsky Dirk , Penney Matthew , Hagerud Anja
Published: March 2020

Mineral resources are used in large quantities than ever before because they are fundamental to our modern society. To this front and facing an up-scaling challenge, the EIT Raw-Materials funded project SIT4ME (Seismic Imaging Techniques for Mineral Exploration) was launched involving several European institutions. As part of the project, a dense multi-method seismic dataset was acquired in the Zinkgruvan mining area at the Bergslagen mineral district of Sweden, which hosts one of the largest volcanic-hosted massive sulphide (VMS) deposits in the country.

In November 2018, a dense multi-method seismic dataset was acquired in the Zinkgruvan mining area, in a joint collaborative approach among Swedish, Spanish and German partners. A combination of sparse 3D grid and dense 2D profiles in an area of approximately 6 km2 was acquired using a 32t seismic vibrator (10-150 Hz) of TU Bergakademie Freiberg, enabling reasonable pseudo-3D sub-surface illumination. For the data acquisition, a total of approximately 1300 receiver positions (10-20 m apart), using different recorders, and 950 source positions were surveyed. All receivers were active during the data acquisition allowing a combination of 2D and semi-3D data to be obtained for various imaging and comparative studies. The main objective of the study, apart from its commercial-realization approach, was also to provide information useful for deep-targeting and structural imaging in this complex geological setting. The main massive-sulphide bearing horizon, Zinkgruvan formation, is strongly reflective as correlated with the existing boreholes in the mine. Careful analysis of the seismic sections suggests a dominant northeast-dipping structure, consistent with the general plunge of the main Zinkgruvan fold that has been suggested in the area.

Acknowledgements: EIT-RawMaterials is gratefully thanked for funding this up-scaling project 17024.
Geological Processes to Consider for Modeling the Distribution of Hydrogeological Properties in Fractured Crystalline Rocks on a Site Scale
Authors: Achtziger-Zupancic Peter , Loew Simon
Published: March 2020

Reliable predictions of the distribution of permeabilities on site scale are economically relevant in a wide range of geoscientific disciplines. Not only are predictions important for modeling hydrogeological conditions at site scale but also for using the underground safely and sustainably.

Scale dependent, different geological processes are influencing the distribution of hydrogeological properties. A dataset of about 5000 inflows from individual transmissive fractures draining to about 660 km of drifts and 57 km of boreholes has been compiled into depths of 2000 mbgs of the Variscan age German Ore Mountains (Erzgebirge/Krušné hory). Fracture closure with increasing depth is a main process controlling the distribution of transmissivities. Additionally, orientation, age and mode of fault zones exert a major control on the local distribution of inflows. These factors are locally overprinted by with the presence of contact metamorphic aureoles around Variscan granitic intrusions as seen from transmissivity reversals with depth. However, as seen from a decreasing trend of mean log hydraulic conductivity and permeability, the contact metamorphism exerts minor control on the rock mass hydrology with depth than the decreasing secondary porosity provided by fractures.

These findings are in accordance with results deduced from a worldwide permeability compilation of about 30000 single in-situ permeability measurements to depths of 2000 mbgs. Geological influences on the distribution have been analyzed on permeability-depth relationships using log-log regressions. Depth is generally the most important geological factor, resulting in a permeability decrease of three to four orders of magnitude in the investigated depth range. Beside depth, most influential factors are the long-term tectono-geological history described by geological province which locally is overprinted by current seismotectonic activity as determined by peak ground acceleration. Although petrography might be of local importance, only a low impact has been observed for the global dataset, besides lithologies allowing for karstification.

In summary, the multi-variate analysis of the datasets has improved our generic understanding of the distribution of hydrogeological properties and provides a basis to model hydrogeological processes in fractured crystalline rocks.
Aircraft-based 2- and 3D Trace Gas Measurements with HAIDI (Heidelberg Airborne Imaging DOAS Instrument) - Results of the EMeRGe Missions
Authors: Bigge Katja , Pöhler Denis , Frieß Udo , Platt Ulrich
Published: March 2020

Today, the majority of humanity lives in urban areas. Accordingly, major population centers are a significant source of a multitude of atmospheric emissions from human activity such as traffic, heating, industry or power generation. Pollutants directly impact the local inhabitant's health, but are also transported to neighbouring areas, undergo chemical evolution and can have an impact on climate. To understand and assess effective measures for reducing the effects, it is important to determine the source locations and strengths as well as relevant chemical processes.

Aircraft-based measurements can cover the gap between long-term ground-based and globe-covering satellite instruments with its high temporal and spatial coverage during flight time. Remote sensing methods in particular allow a fast and wide-spread probing of atmospheric trace gas distributions. Within this context, the HAIDI (Heidelberg Airborne Imaging DOAS Instrument) instrument was designed to provide data of extremely high temporal and spatial resolution (40m x 40m at 1.5 km flight altitude, 266m x 266m at 10 km flight altitude, at 10 ms temporal resolution) in 2D and 3D during overflight.

During the EMeRGe (Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global Scales) missions HAIDI was part of the comprehensive set of measurement equipment installed on the research airplane HALO (High Altitude and LOng range re-search aircraft) of the DLR (German Aerospace Center). The EMeRGe missions targeted the emission outflows of megacities to investigate their compositions and the atmospheric impact of urban pollution. One mission part was conducted in Europe (July 2017) and aimed at areas around Paris, London, the Po area, Madrid and the Benelux area. For contrast, the second mission part was based in Taiwan (March 2018) and investigated Taiwan cities, Bangkok, Manila, Japanese cities and China outflow.

HAIDI derived a number of trace gases such as NO2, SO2, BrO and HCHO. Due to large concentrations present, for NO2 and SO2 in particular it was possible to obtain high-resolution 2D data of megacity areas and plumes of megacities, powerplants and ships and estimate their emissions. We will present results of the HAIDI measurements during the EMeRGe mission.
The NASA ORACLES airborne flight projects – lessons learned for future multi-platform missions to study aerosol-cloud-climate interactions
Authors: Redemann Jens ,   The ORACLES science team
Published: March 2020

Three deployments involving the NASA P-3 and ER-2 aircraft in the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) project in September 2016, August 2017 and October 2018 were designed to study the seasonal interactions of biomass burning (BB) aerosols emanating from Southern Africa with the semi-permanent subtropical stratocumulus (Sc) cloud deck over the South-East (SE) Atlantic. We provide a science overview of all deployments, describing novel approaches for coordinating the NASA aircraft with each other, with the Bae-146 aircraft during flights near Ascension Island in 2017, and with satellite overpasses. Based on various examples, we describe the requirements for spatiotemporal coordination and the scientific benefits gleaned from successful synergy of datasets thus obtained. We provide the current status of integrative work that addresses the overarching science questions regarding aerosol-radiation-climate interactions in the region. We conclude by linking the suborbital observations with overarching observational efforts, in particular NASA’s ACCP (Aerosols, Clouds, Convection, and Precipitation) Designated Observable study, which aims to define combinations of orbital and suborbital observing system concepts for addressing integrated aerosol-cloud-climate objectives as defined in the 2017 US Decadal Survey.
Scale-Dependent Worth of QPF for Real-Time Streamflow Forecasting
Authors: Krajewski Witold , Ghimire Ganesh
Published: March 2020

The authors explore uncertainty associated with the quantitative precipitation forecasts (QPF) and its implication to the predictability of real-time streamflow forecasts. Including rainfall forecasts into real-time streamflow forecasting system extends the forecast lead time. As rainfall is a key driver of rainfall-runoff models both past and future rainfall estimates should be used in streamflow and flood forecasting. Since both QPE and QPF are subject to substantial uncertainties, questions arise on the trade-off between the time horizon of the QPF and the accuracy of the streamflow forecasts. Particularly QPF is notorious for its significant uncertainty with respect to location, timing and magnitude. Operational hydrologic services often limit their use of the QPF to one or two days into the future. The authors study this problem systematically using operational models and QPF. Their focus is on scale-dependence of the trade-off between the QPF time horizon and streamflow accuracy. To address this question, the authors first perform comprehensive independent evaluation of QPF at about 140 basins with wide range of spatial scales (10 - 40000 km2) corresponding to U.S Geological Survey (USGS) streamflow monitoring stations over the state of Iowa in Midwestern United States. High Resolution Rapid Refresh (HRRR) is an hourly short-medium range rainfall forecast of up to 18 hours updated every hour with spatial resolution of about 3 km by 3 km. Six-hourly rainfall forecasts are available for up to seven days ahead. Since basins are hydrologically relevant, the authors perform HRRR skill verification for the years 2016-2019 using conventional verification techniques and mean areal precipitation (basin scale rainfall volume) with respect to multi-radar

multi-sensor (MRMS) QPE (gauge-corrected) rainfall. The authors show that the QPF errors/uncertainties are scale-dependent. The QPF skills show increase as the basin scale and lead time of the forecast increases at short-medium range. In the second part of the study, both QPE and QPFs are forced separately to the hydrologic model called hillslope-link model (HLM) used at the Iowa Flood Center for real-time streamflow forecasting for Iowa. The objective is to understand the contribution of QPF uncertainty structure on the skill of streamflow forecasts. Since real-time streamflow observations (15 minutes resolution) are available at USGS sites, the authors incorporate them using a simple data assimilation framework. Several scenarios of forecasts, such as open-loop combined with QPF, persistence-based approach (using streamflow observations) combined with QPF, and open-loop combined with QPF for more than 18 hours horizon is explored. The authors report the contribution of QPF errors on hydrologic predictions across scales and suggest a forecasting scenario that shows the most enhanced predictability of streamflows.
Evolving the Helicopter Emergency Medical Services (HEMS) Tool
Authors: Cross Austin , Avey Stephanie , Veitor Dan
Published: March 2020

The Helicopter Emergency Medical Services (HEMS) tool is designed to be an intuitive web-based platform that presents weather conditions for short-distance and low-altitude flights to non-weather experts quickly and effectively.  Having timely and accurate weather information is crucial for the flight planning needs of the HEMS community.  

The Aviation Weather Center (AWC) has been working closely with FAA partners from the Aviation Weather Research Program (AWRP) and the Aviation Weather Demonstration and Evaluation (AWDE) Services group to enhance the ceiling and visibility capabilities within the tool, as well as the usability of the tool to meet user needs. An updated gridded ceiling and visibility analysis, as well as forecast ceiling and visibility, are two recent improvements based on user evaluation results that are set for operational implementation in early spring 2020. Evaluations have shown that users span well beyond helicopter pilots, and therefore the tool must evolve to accomodate all low level flight users, including unmanned aerial systems (UAS)/urban air mobility (UAM) users.

To meet this evolution, AWC will be incorporating the HEMS tool capabilities into the same framework as the one-stop-shop tool for general aviation users, the Graphical Forecasts for Aviation (GFA). The Low Altitude GFA (GFA-LA) will continue to meet the needs of the HEMS community, and will provide better consistency with other products across aviationweather.gov providing a common user experience for all aviation users. Research into automated quality control of surface observations is expected to allow addition of non-regulated station information to be added, and work on on-the-fly visualizations is expected to allow three dimensional data interrogation. Recent updates to the HEMS tool, as well as future plans to evolve HEMS into GFA-LA will be presented.
Recent trends in crop rotation in the Czech Republic and associated soil erosion risks
Authors: Krasa Josef , Dostal Tomas , Zumr David , Tejkl Adam , Bauer Miroslav
Published: March 2020

In last decades several trends have been visible in agricultural land use in the Czech Republic. Among all oil rape production was raised (mainly in last 10 years) and maize production was enlarged in some regions where bio-fuel stations have been newly built. As a row crop, maize without proper management control leads to accelerated water erosion and sediment transport. Oil rape is generally considered as a relatively soil preserving crop, supporting also infiltration by a root system. But seeding period of oil rape in the Czech Republic starts in August still in the peak period of erosive rainstorms. Recent risks associated with both crops will be presented by data from field rainfall-runoff simulations, targeted on developing actual crop protection factor (C-factor) of USLE for Czech conditions. The second source of the data for presenting risk trends is Czech soil erosion monitoring database of State Land Office (https://me.vumop.cz/), where many occurrences of erosion damages were identified on both crops. Finally, study focused on bare soil remote sensing via Landsat 8 and Sentinel 2 in recent years showed link between erosion risks and the two above mentioned crops.

National implementation of European cross compliance policy in the Czech Republic targeted the protection also to fight these risky trends, but the power of the agricultural policy, as will be presented, is limited in this scope. We see similar threats in other European countries and we were able to visit North East China regions with intensive corn production where soil erosion by water is causing serious soil and water degradation. Therefore, shared knowledge on strategies how to prevent risky soil managements could lead to benefits in both European and Chinese conditions.

The contribution was prepared in the frame of projects No. QK1920224 (Possibilities of anti-erosion protection on farms to avoid the use of glyphosate), and H2020 SHUi (Soil Hydrology research platform underpinning innovation to manage water scarcity in European and Chinese cropping systems).
Detecting regimes of the mid-latitude atmospheric circulation by nonlinear data decomposition
Authors: Mukhin Dmitry , Hannachi Abdel
Published: March 2020

We suggest a method for nonlinear analysis of atmospheric circulation regimes in the middle latitudes. The method is based on the kernel principal component analysis allowing to separate principal modes of dynamics entangled in data. We propose a new kernel function accounting specifics of large-scale wave patterns in the mid-latitude atmosphere. First, capabilities of the method are shown by the analysis of the 3-layer quasi-geostrophic model of the Northern hemisphere atmosphere: a statistically significant set of modes can be detected by the method from relatively short (several thousand days) time series. Next, we consider reanalysis data of wintertime geopotential height anomalies over the Northern hemisphere from 1950 to the present. The principal components obtained uncover several recurrent and persistent wave structures which are associated with different weather regimes. We find that there is a pronounced inter-annual and decadal variability in the dominance of different modes in different years. Possible climatic and external forcings which impact such variability as well as long-term predictability of anomalous weather seasons based on the obtained components are discussed.
Visualize the change
Authors: Giunta Paola
Published: March 2020

In Geosciences the use of visualizations - diagrams, images, animations, maps, is an essential tool in helping students to visualise Earth and its changes.

In a secondary high school class, I observed how helpful the use of visualization tools was in learning a geoscience topic such as the climate change.
I created a guided educational activity to enhance students’ knowledge about climate change, using visualization tools from the simple images to the use of the Google Earth software.

The aim of the project was to assess the effectiveness of an activity based on ”situated learning” about raising the awareness on climate change and global warming in our students.
Therefore this might encourage students to enhance the culture of prevention to aim to a sustainable future.
Base-salt Relief Controls Salt-related Contractional Styles in the Translational Domain of the Outer Kwanza Basin, offshore Angola
Authors: Erdi Aurio , Jackson Christopher
Published: March 2020

Salt-bearing passive margins are typically characterized by thin-skinned, gravity-driven deformation above a salt detachment, resulting in kinematically-linked domains of updip extension and downdip contraction. These domains are commonly connected by a mid-slope translational domain in which salt-related structures accommodate local extensional and contractional strains associated with salt flow across base-salt relief. Despite a general understanding of these salt-tectonic processes and products, little is still known about the detailed geometric and kinematic evolution of mid-slope contractional structures.

We use a high-quality, depth-migrated three-dimensional seismic reflection dataset located in the mid-slope translational domain of the Outer Kwanza Basin, offshore Angola. We analysed the seismic-stratigraphic architecture of the Aptian salt and its immediate Albian overburden to reveal the distribution of local, salt-related contractional structures above varying geometries of base-salt relief.

Our analysis reveals two types of salt-related contractional structures, variably distributed in terms of their trend relative to underlying ramps that trend NW or N. The first type is represented by salt-cored anticlines, the limbs of which may be dissected by salt-detached thrusts. The folds trend parallel to the NW- or N-trending ramps, being located either updip or directly above the underlying ramp. These folds increase in amplitude and decrease in wavelength basinward, and are also locally polyharmonic; showing an upwards increase in wavelength, but a decrease in amplitude. The second type of structure is represented by two sub-types of salt walls: (i) reactive salt walls, and (ii) squeezed salt walls. These salt walls trend broadly parallel to, and are located above or downdip of NW-trending, basinward- and landward-facing ramps. The salt-cored anticlines are formed by local contraction associated with salt flow deceleration above ramp-updip. This process of local contraction also locally induces active rise and overburden piercement as salt walls translate over local base-salt structural highs. Still, other salt walls are locally contracted on the basinward-facing ramp during salt flow seaward, resulting in the squeezed salt wall.

We show that careful seismic-stratigraphic analysis of salt and overburden deformation, in the context of the underlying base-salt geometry, reveals complex patterns of salt structure evolution during seaward translation across the midslope translational domain. The results are applicable along salt-bearing passive margin worldwide and may provide an important insight in identifying potential plays along the midslope translational domain, where major deepwater oilfields reside.
Modelling the evolution of CMEs and their shocks through different solar wind structures
Authors: Palmerio Erika , Lee Christina , Mays Leila , Odstrcil Dusan
Published: March 2020

The evolution of coronal mass ejections (CMEs) as they travel away from the Sun is one of the major issues in heliophysics and space weather. After erupting, CMEs propagate outwards through the background solar wind flow, which in turn may significantly affect CME evolution by means of e.g. acceleration, deflection, and/or rotation. In order to determine to which extent the ambient wind can alter the speed, trajectory, and orientation of a CME, we run a series of 3D magnetohydrodynamics simulations (using the coupled solar–heliospheric WSA–Enlil model) to conduct a multi-vantage point study of the radial and longitudinal evolution of CME structures as they propagate up to Earth’s (1 AU) and Mars’ (1.5 AU) orbits. We explore a broad range of input CME parameters (initial radial speed, angular width) and ambient solar wind conditions (slow versus fast wind) to investigate the different evolutionary behaviours of CMEs and their driven shocks and sheath regions. To study the radial and longitudinal evolution for the modelled CME ejecta and shock events, we examine the resulting magnetic field and plasma time series at different heliocentric distances (0.5 AU, 1 AU, and 1.5 AU) and heliolongitudes (in 30° increments). This work will help establish a set of expected CME behaviours at Earth’s and Mars’ radial distances, which can be used for analysing real CME events.
Local climate of Zachary glacier, North East Greenland
Authors: Reijmer Carleen , Khan Abas , Rignot Eric , van de Broeke Michiel , Noël Brice
Published: March 2020

In August 2016, two automatic weather stations (AWS) were placed on Zachary glacier, North East Greenland. They were installed in support of a project investigating the surface mass balance, ice velocity and calving conditions of Zachary glacier. The stations are full energy balance stations, i.e. they measure all parameters (air temperature, wind speed, relative humidity, air pressure, and short and long wave incoming and outgoing radiation) necessary to derive the full surface energy balance. In addition, the stations are equipped with a sonic height ranger in combination with a draw wire to measure snow accumulation and ice melt, respectively, and a GPS to monitor glacier velocity. These stations provide insight in the local climate of north east Greenland, a region for which only limited in situ data is available.

The AWS were located initially at ~145 m a.s.l., about 13 km from the glacier front (AWS23), and at  ~535 m a.s.l., about 35 km from the glacier front (AWS22). Both are moving reasonably fast (0.7 – 1.7 km/yr) towards the front, which has an impact on observed variables mainly since station elevation decreases, although changing (surrounding) topography impacts wind and radiation observations as well. Results show that both sites exhibit a strong katabatic signature, with directional constancies around 0.9, and wind speeds in winter being twice as strong as in summer. Temperature difference between the sites reflect the height difference, and is smaller in summer due to the melting surface impacting the near surface temperature. The lapse rate increases from ~0.5 °C/100 m in summer to ~0.7°C/100 m in the other seasons. The lower station, AWS23, is located in the ablation zone and has experienced on average 2.1 m ice melt over the past 3 years. At the higher station the mass budget appears to be in balance over this period.

The 3.5 years of available station data is compared with regional climate model RACMO2.3p2 output (5.5 km resolution), where monthly averaged data from the grid point nearest to the average station location is used. Initial differences in surface pressure reflect a difference in model grid height and station elevation (stations being located at lower elevation), while an increase in the absolute difference reflects the fast movement of the glacier transporting the AWS to lower elevations (30 and 70 m lowering for AWS22 and 23 respectively). The model overestimates temperature at AWS22 (1.3 °C), and wind speeds are too high at both sites.
Intercropping fava bean with broccoli can improve soil properties while maintaining crop production under Mediterranean conditions
Authors: Marcos-Pérez Mariano , Sánchez-Navarro Virginia , Zornoza Raúl
Published: March 2020

Including legumes in intercropping systems may be regarded as a sustainable way to improve soil quality, fertility and land productivity, mostly due to facilitation processes and high rhizospheric activity which can mobilize soil nutrients for plants. Improvements in production and soil quality depend on inherent soil properties, climatic conditions, adopted management practices and fertilization, among others. The aim of this study was to assess the effect of the association between broccoli (Brassica oleracea var italica) and fava bean (Vicia fava) grown under different intercropping patterns on crop production, soil organic carbon (SOC), total nitrogen (Nt), soil aggregate stability (SAS) and soil fertility, compared to a broccoli monocrop. We defined a randomised block field experiment with three replications assessing the effect of monocropping, row 1:1 intercropping, row 2:1 intercropping and mix intercropping, with 30% reduction in fertilization in intercropped systems compared to monocrop. Soil sampling took place at harvest in February 2019. Results showed that the broccoli-fava bean intercropping significantly increased the general land production, with similar broccoli yield of 20000 kg ha-1 in all treatments, plus 8000 kg ha-1 coming from fava bean. Crop diversification and fava bean cultivation even in monocrop significantly increased SOC and Nt compared to broccoli monocrop. SOC and Nt were 1.06% and 0.09%, respectively, for broccoli monocrop, while they had average values of 1.29% and 0.12%, respectively for the intercropped systems. SAS was also significantly affected by crop diversification, with increases in the proportion of the macroaggregates (size >2 mm) with intercropping. Broccoli monocrop showed an average proportion of these macroaggregates of 9.19%, while they increased up to 17.51% in intercropped systems. CEC was not significantly affected by intercropping SAS showing almost same percentage of aggregates independently of the treatment. Available P significantly increased in intercropped systems, likely due to increased microbial activity with the simultaneous growth of the two crop species. However, no significant effect of intercropping was observed with any other nutrient (Ca, Mg, K, Mn, Cu, Fe, Zn and B), suggesting that microbial communities activated by the crop association are highly related to P mobilization but not so intensively involved in other nutrients. Thus, intercropping systems like broccoli-fava bean association can be regarded as a viable alternative for sustainable crop production while increasing soil fertility despite reducing the addition of external fertilization. However, more crop cycles are needed to confirm this trend.
Dependence of GPM precipitation product performance on the spatial extent of precipitation system and relative location in precipitation system
Authors: Li Runze , Wang Kaicun , Qi Dan
Published: March 2020

Evaluations of satellite precipitation estimates have been routinely conducted, often in individual gridbox. However, real precipitation is organized as precipitation system in space with a certain extent and structure. Evaluation from the perspective of precipitation system to understand the relationship between satellite errors with the spatial extent of precipitation system and relative location in precipitation system may help to the better knowledge of satellite error sources but has rare been concerned. To address this issue, the Integrated Multi-satellitE Retrievals for GPM (IMERG) V05B final run half-hourly product is evaluated in this study with hourly rain gauge data collected at approximately 50,000 stations in China. We first identify the precipitation system in IMERG and make comparison in gridboxes with gauge observations as a function of gridboxes’ distance to the boundaries of system and the system sizes to investigate their relationships. Our results show that the false alarm proportions generally decrease as the increase of precipitation system sizes, while it is opposite for the miss proportions. Both the miss and false alarm proportion evidently decrease with the longer distance from the boundaries. Over 90% false alarms occur within the distance of 10% of the square root of precipitation system sizes from the boundaries, while 90% misses locate within the distance of 20% the square root of system sizes. The difference between the false alarm proportion inside the systems and miss proportion outside the systems in accordant distances from the boundaries indicate the generally overestimation of IMERG precipitation system sizes, but much severer for small systems than large systems. For the hit bias, IMERG generally underestimates in small precipitation systems but have regional-dependent sign of bias for larger systems. Accordantly, IMERG underestimates the hit precipitation rates for all distances from the boundaries, but the situation is more complex for larger precipitation systems, with an overestimation for about 0-50 km but underestimation for about 50-200km and again overestimation for over about 200km, indicating the evident location-dependent errors in precipitation system of IMERG.
Importance of Stratospheric Polar Vortex Events for Seasonal Predictability of Sea Level Pressure over the North Atlantic and Europe
Authors: Baehr Johanna , Wett Simon , Dobrynin Mikhail , Domeisen Daniela
Published: March 2020

The downward influence of the stratosphere on the troposphere can be significant during boreal winter when the polar vortex is most variable, when major circulation changes in the stratosphere can impact the tropospheric flow. These strong and weak vortex events, the latter also referred to as Sudden Stratospheric Warmings (SSWs), are capable of influencing the tropospheric circulation down to the sea level on timescales from weeks to months. Thus, the occurrence of stratospheric polar vortex events influences the seasonal predictability of sea level pressure (SLP), which is, over the Atlantic sector, strongly linked to the North Atlantic oscillation (NAO).
We analyze the influence of the polar vortex on the seasonal predictability of SLP in a seasonal prediction system based on the mixed resolution configuration of the coupled Max-Planck-Institute Earth System Model (MPI-ESM), where we investigate a 30 member ensemble hindcast simulation covering 1982 -2016. Since the state of the polar vortex is predictable only a few weeks or even days ahead, the seasonal prediction system cannot exactly predict the day of occurrence of stratospheric events. However, making use of the large number of stratospheric polar vortex events in the ensemble hindcast simulation, we present a statistical analysis of the influence of a correct or incorrect prediction of the stratospheric vortex state on the seasonal predictability of SLP over the North Atlantic and Europe.
Arctic Mediterranean Exchanges: A consistent volume budget and trends in transports from two decades of observations
Authors: Østerhus Svein , Woodgate Rebecca , Valdimarsson Héðinn , Turrell Bill , de Steur Laura , Quadfasel Detlef , Olsen Steffen M. , Moritz Martin , Lee Craig M. , Larsen Karin Margretha , Jónsson Steingrímur , Johnson Clare , Jochumsen Kerstin , Hansen Bogi , Curry Beth , Cunningham Stuart , Berx Barbara
Published: March 2020

Conditions in the Arctic are in part driven by the ocean state in the Arctic Mediterranean (AM), the collective name for the Arctic Ocean, the Nordic Seas, and their adjacent shelf seas. Exchange between the lower latitude ocean basins and this region occurs through the Bering Strait (Pacific inflow) and through the passages across the Greenland-Scotland Ridge (Atlantic inflow). These waters are subsequently modified within the AM. The modified waters leave the AM in several flow branches, which are grouped into two different categories: (1) overflow of dense water through the deep passages across the Greenland-Scotland Ridge, and (2) outflow of light water (surface outflow) on both sides of Greenland. These exchanges transport heat and salt into and out of the AM and are important for conditions in the AM. They are also part of the global ocean circulation and climate system. Attempts to quantify the transports by various methods have been made for many years, but only recently, the observational coverage has become sufficiently complete to allow an integrated assessment of the AM-exchanges based solely on observations.

In this EGU contribution, we focus on the observations (incl. volume transport time series) of all the main AM-exchange branches collected in the last 20 to 30 years.
Going beyond FAIR to increase data reliability
Authors: Koedel Uta , Dietrich Peter
Published: March 2020

The FAIR principle is on its way to becoming a conventional standard for all kinds of data. However, it is often forgotten that this principle does not consider data quality or data reliability issues. If the data quality isis not sufficiently described, a wrong interpretation and use of these data in a common interpretation can lead to false scientific conclusions. Hence, the statement about data reliability is an essential component for secondary data processing and joint interpretation efforts. Information on data reliability, uncertainty, quality as well as information on the used devices are essential and needs to be introduced or even implemented in the workflow from the sensor to a database if data is to be considered in a broader context.

In the past, many publications have shown that the same devices at the same location do not necessarily provide the same measurement data. Likewise, statistical quantities and confidence intervals are rarely given in publications in order to assess the reliability of the data. Many secondary users of measurement data assume that calibration data and the measurement of other auxiliary variables are sufficient to estimate the data reliability. However, even if some devices require on-site field calibration, that does not mean that the data are comparable. Heat, cold, internal processes on electronic components can lead to differences in measurement data recorded with devices of the same type at the same location, especially with the increasingly complex devices themselves.

The data reliability can be increased by implementing data uncertainty issues within the FAIR principle. The poster presentation will show the importance of comparative measurements, the information needs for the application of proxy-transfer functions, and suitable uncertainty analysis for databases.
Pyrocumulonimbus Events over British Columbia, 2017: The Long-term Transport and Radiative Impacts of Smoke Aerosols in the Stratosphere
Authors: Das Sampa , Colarco Peter , Oman Luke , Taha Ghassan , Torres Omar
Published: March 2020

Interactions of meteorology with wildfires in British Columbia, Canada during August 2017 led to several extreme pyrocumulonimbus (PyroCb) events that resulted in the injection of smoke aerosols and other combustion products into the lower stratosphere. These plumes of stratospheric smoke were observed by many satellite instruments to have elevated values of aerosol extinction and backscatter compared to the background state and were readily tracked as they spread across the Northern Hemisphere and resided in the lower stratosphere for about ten months following the fires. To investigate the radiative impacts of these events on the Earth system, we performed a number of simulations with the Goddard Earth Observing System (GEOS) global Earth system model, which includes detailed aerosol and chemistry packages coupled to the underlying model physical and dynamical cores. Retrievals of smoke aerosol properties from space-based OMPS/NPP, SAGE-III/ISS, and CALIOP/CALIPSO instruments were used to calibrate the injection location, timing, amount, and optical properties of the smoke aerosols. The resulting simulations of three-dimensional smoke transport were evaluated over a year following the injections using observations from OMPS-Limb Profiler (LP), which provides aerosol retrievals at a high temporal and vertical resolution for altitudes greater than 10 km. We found that diabatic heating due to aerosol absorption, combined with the large-scale atmospheric motions, play important roles in lifting the smoke plumes from near the tropopause altitudes to about 22 km into the atmosphere. The model was able to simulate the rate of plume ascent from lower to the middle stratosphere, hemispherical spread and residence time of the smoke aerosols in the stratosphere in close agreement with OMPS-LP. Finally, we also investigated the impact of these PyroCb emitted smoke aerosols on the stratospheric radiative forcing and the subsequent impact on temperature tendencies.
Differences between urban and natural stream temperatures across the eastern United States
Authors: Kelleher Christa , Hurst Eliza
Published: March 2020

Stream temperature is inherently shaped by human activity, often reflecting reduced riparian cover, runoff from impervious surfaces, limited connectivity between groundwater and surface waters, and a host of other sources of water delivery, including stormwater, wastewater, and dam releases.  This is especially true in urbanized areas, where heat exchanges may be additionally altered by urban hydrology, delivering warm pulses of water during heavy storms that locally elevate water temperatures.  While this effect has been documented in several cities, no comprehensive summary of these impacts exists at regional and larger scales.  Our work documents the impact of urbanization on stream temperatures during wet and dry periods in small streams for several cities across the eastern United States.  Our work seeks to benchmark how stream temperature surges during storms and average stream temperatures in more urbanized watersheds differ from nearby forested, less-impacted sites.  We show that the occurrence and magnitude of temperature surges as well as the statistical characteristics of dry-day stream temperature varies with climate and level of imperviousness.  Interestingly, comparisons within and across cities demonstrate the complex responses of stream temperature to urbanization, suggesting that the human imprint on stream temperature signals is highly variable and reflects site specific characteristics rather than regional influences.
Copula-based multivariate methods in hydroclimatic applications: avoiding common misconceptions and pitfalls.
Authors: Tootoonchi Faranak , Haerter Jan , Raty Olle , Grabs Thomas , Sadegh Mojtaba , Teutschbein Claudia
Published: March 2020

For most hydroclimatic applications, precipitation and temperature are of particular interest for modeling purposes and future projections. Both variables strongly affect the water cycle, they can easily be measured and have the benefit of typically being readily available from many meteorological stations worldwide. In order to account for precipitation and temperature variability, their interdependence and their physical correlation, several multivariate analysis methods have been adopted in the hydroclimatic literature in recent years. In fact, the total number of papers published per year has nearly doubled from roughly 300 per year in 2010 to nearly 600 per year in 2018. In line with this increasing use of multivariate methods, the notion of Copula-based probability distribution has also attracted tremendous interest to deal with the complexity of compound events in the multidimensional pool. A Copula is a function that connects a multivariate distribution to its one-dimensional margins. The Copula concept is particularly advantageous, because it allows for a joint distribution of random variables with great flexibility for the marginal distribution and because it takes into account the dependence structure of these variables. However, there seems to be a lack of comprehensive understanding of the fundamental requirements of the Copula concept such as the strength and dependability of correlation between variables, autocorrelation effects and the choice of representative Copula families, which potentially compromises the accuracy of projections of future environmental processes and natural hazards.

Therefore, we bring forward a step-by-step guide on Copula-based modeling for hydroclimatic variables such as temperature and precipitation, which (1) provides end-users with an overview of necessary requirements, statistical assumptions and consequential limitations of Copulas, and (2) offers clear guidelines on how to implement Copulas. Based on a systematic literature, we also discuss common pitfalls and misconceptions using a specific hydroclimatic case study in Sweden and provide a Copula modeling framework to support researchers and decision makers in addressing climatological hazards and sustainable development.

 
The PMIP4-CMIP6 Last Glacial Maximum experiments: preliminary results and comparison with the PMIP3-CMIP5 simulations
Authors: Kageyama Masa ,   PMIP4 LGM group
Published: March 2020

The Last Glacial Maximum (LGM, ~21,000 years ago) has been a major focus for evaluating how well state-of-the-art climate models simulate climate changes as large as those expected in the future using paleoclimate reconstructions. A new generation of climate models have been used to generate LGM simulations as part of the Palaeoclimate Modelling Intercomparison Project (PMIP) contributionto CMIP6. Here we provide a preliminary analysis and evaluation of the results of these LGM experiments and compare them with the previous generation of simulations (PMIP3-CMIP5). We show that the PMIP4-CMIP6 are globally less cold and less dry than the PMIP3-CMIP5 simulations, most probably because of the use of a more realistic specification of the northern hemisphere ice sheets in the latest simulations although changes in model configuration may also contribute to this. There are important differences in both atmospheric and ocean circulation between the two sets of experiments, with the northern and southern jet streams being more poleward and the changes in the Atlantic Meridional Overturning Circulation being less pronounced in the PMIP4-CMIP6 simulations than in the PMIP3-CMIP5 simulations. Changes in simulated precipitation patterns are influenced by both temperature and circulation changes. Differences in simulated climate between individual models remain large so, although there are differences in the average behaviour across the two ensembles, the new simulation results are not fundamentally different from the PMIP3-CMIP5 results. Evaluation of large-scale climate features, such as land-sea contrast and polar amplification, confirms that the models capture these well and within the uncertainty of the palaeoclimate reconstructions. Nevertheless, regional climate changes are less well simulated: the models underestimate extratropical cooling, particularly in winter, and precipitation changes. The spatial patterns of increased precipitation associated with changes in the jet streams are also poorly captured. However, changes in the tropics are more realistic, particularly the changes in tropical temperatures over the oceans. Although these results are preliminary in nature, because of the limited number of LGM simulations currently available, they nevertheless point to the utility of using paleoclimate simulations to understand the mechanisms of climate change and evaluate model performance.
Measuring Anatolian plate velocity and strain with Sentinel-1 InSAR and GNSS data: implications for fault locking, seismic hazard, and crustal dynamics
Authors: Weiss Jonathan , Walters Richard , Wright Tim , Morishita Yu , Lazecky Milan , Wang Hua , Hussain Ekbal , Hooper Andrew
Published: March 2020

Geodetic measurements of small rates of interseismic crustal motion made at high spatial resolutions and over large areas are crucial for understanding the earthquake cycle, characterizing spatial variations in lithosphere rheology and fault frictional properties, illuminating the mechanics of large-scale continental deformation, and improving earthquake hazard models. The densification of Global Navigation Satellite System (GNSS) networks has provided an unprecedented view of the kinematics of deforming regions. However, large gaps in spatial coverage still hamper our ability to fully characterize patterns of surface deformation. Interferometric synthetic aperture radar (InSAR), and the Sentinel-1 (S-1) satellites in particular, have the potential to overcome this obstacle by providing spatially continuous measurements of surface motions, without instruments on the ground, with precision approaching that obtained from GNSS, and at a resolution of a few tens of meters. In order to manage and process the large data volumes produced by S-1, we have developed open-source, automated workflows to efficiently generate interferograms and line-of-sight (LOS) velocity fields. These outputs are valuable for a range of applications, from earthquake rapid-response to investigating human-induced ground-level changes. In this talk, we demonstrate our ability to measure plate-scale interseismic deformation using data from the first ~5 years of the S-1 mission. We estimate LOS velocities for the Anatolian microplate, an area encompassing ~800,000 km2 and including the highly seismogenic North Anatolian Fault Zone (NAFZ). By combining S-1 InSAR and GNSS data, we create high-resolution surface velocity and strain rate fields for the region, which illuminate horizontal deformation patterns dominated by the westward motion of Anatolia relative to Eurasia, localized strain accumulation along the NAFZ, and rapid vertical signals associated with groundwater extraction. Relatively low levels of strain characterize other active regions including the East and Central Anatolian Fault Zones and the Western Anatolian Extensional Province. We find that GNSS data alone are insufficient for characterizing key details of the strain rate field that are critical for understanding the relationship between strain accumulation and release in earthquakes. We highlight two important results stemming from our work including probabilistic estimates of the recurrence times of earthquakes of varying magnitudes for the region and a new NAFZ locking distribution that shows close correspondence to the surface rupture extents of large 20th century earthquakes.