bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlating surface water flood damages in three Indonesia cities
Authors: Farnham Matthew , Camacho-Suarez Vivian , Milne Alistair , Hillier John , Yu Dapeng , Slater Louise , Whyte Laura , Baruch Avinoam
Published: March 2020

Despite a high growth rate of over 5%, the insurance penetration rate in Indonesia is low, at roughly 2.77 percent and is one of the least developed insurance market among ASEAN economies. A primary explanation for the lack of motivation for taking up insurance is due to the lack of understanding of the multitude of risks from natural hazards the Indonesian market faces, principally of flooding. The purpose of this research is to assess the flood correlation between three of the major cities (Jakarta, Semarang, and Solo) on the island of Java. These highly populated and financial centres of Indonesia are most prone to the rainfall extremes during the Monsoon Season (November – March), many of which causes flooding. All the historical rainfall events were extracted from ECMWF’s ERA-5 hourly rainfall dataset (1979 – 2018). The top 10 events for each city were selected based on peak rainfall intensity. For the selected events in a city, rainfall records of the same period were extracted for the other two cities. This results in 30 simulations per city. Using a 2D hydraulic modelling tool (FloodMap), surface water flood footprints were generated for the events. In the absence of depth-damage curves, the number of buildings flooded under each event were used as an approximation to building damages. Damage to buildings due to surface water flooding in Solo and Semarang were found to be most correlated, with a significant number of buildings flooded in both cities in 15 out of the 20 paired events. Solo and Jakarta show some correlation (7 out of 20) whilst flooding in Semarang and Jakarta are least correlated (4 out of 20). This study is an initial analysis relevant to the modelling of catastrophes in a relatively data sparse environment, providing an approximation of the correlation of flooding between three Indonesian cities. Further studies are required to develop pragmatic approaches to complement catastrophe modelling that integrate the spatial correlation between flood damages in cities.
Comparing Causal Discovery Methods using Synthetic and Real Data
Authors: Käding Christoph , Runge Jakob
Published: March 2020

Unveiling causal structures, i.e., distinguishing cause from effect, from observational data plays a key role in climate science as well as in other fields like medicine or economics. Hence, a number of approaches has been developed to approach this. Recent decades have seen methods like Granger causality or causal network learning algorithms, which are, however, not generally applicable in every scenario. When given two variables X and Y, it is still a challenging problem to decide whether X causes Y, or Y causes X. Recently, there has been progress in the framework of structural causal models, which enable the discovery of causal relationships by making use of functional dependencies (e.g., only linear) and noise models (e.g., only non-Gaussian noise). However, each of them is coming with its own requirements and constraints. While the corresponding conditions are usually unknown in real scenarios, it is quite hard to choose the right method for every application in general.

The goal of this work is to evaluate and to compare a number of state-of-the-art techniques in a joint benchmark. To do so, we employ synthetic data, where we can control for the dataset conditions precisely, and hence can give detailed reasoning about the resulting performance of the individual methods given their underlying assumptions. Further, we utilize real-world data to shed light on their capabilities in actual applications in a comparative manner. We concentrate on the case considering two uni-variate variables due to the large number of possible application scenarios. A profound study, comparing even the latest developments, is, to the best of our knowledge, so far not available in the literature.
Fidelity of CORDEX Evaluation runs under Non-stationary climate
Authors: Singh Swati , Salvi Kaustubh , Ghosh Subimal , Karmakar Subhankar
Published: March 2020

The downscaling approaches: Statistical and Dynamic, developed for regional climate predictions, have both advantages and limitations. The statistical downscaling is computationally inexpensive but suffers from the violation of the assumption of stationarity in statistical (predictor-predictand) relationship. The dynamical downscaling is assumed to take care of stationarity but suffers from the biases associated with various sources.  Here we propose a joint approach of both the methods by applying statistical methods: bias correction & statistical downscaling to Coordinated Regional Climate Downscaling Experiment (CORDEX) evaluation runs. The evaluation runs are considered as perfect simulations of CORDEX Regional Climate Models (RCMs) with the boundary conditions by ERA-Interim reanalysis data. The statistical methods are also applied to ERA-Interim reanalysis data and compared with observation data for Indian Summer Monsoon characteristics. We evaluate the ability of statistical methods under the non-stationary environment by taking the difference of years close to extreme future runs (RCP8.5) as warmer years and preindustrial runs as cooler years. We find statistical downscaling of CORDEX evaluation runs shows skill in reproducing the signal of non-stationarity. The study can be extended methods by applying statistical downscaling to CORDEX RCMs with the CMIP5 boundary conditions. 
Spatiotemporal analysis of the housing bubble’s contribution to the proliferation of illegal landfills – The case of Gran Canaria
Authors: Quesada-Ruiz Lorenzo Carlos , Perez Liliana , Rodriguez-Galiano Victor , Aragones David
Published: March 2020

The management of disposed waste in illegal landfills (ILs) is a significant problem in contemporary societies due to respective hazards for the environment and human health. This study investigates the spatiotemporal distribution of IL occurrence for 2000, 2006 and 2012 in two representative areas of Gran Canaria island: northwest (Zone A) and east (Zone B). The interannual growth rate of surfaces affected by ILs for the period between 2000 and 2006 was 4.5% and 9.5% and between 2006 and 2012 it was 6.6% and 6.7%, for Zone A and Zone B respectively. The growth of ILs between 2000 and 2006 was higher in urban areas, spaces under construction, and industrial zones, and may be closely related to the process of urban expansion linked to the real estate boom. The latter would have a deep impact on the landscape due to the proliferation of illegal construction and demolition waste. The growth rate of ILs in urban environments fell during the later period of urban expansion. Besides, this work shows the application of cellular automata (CA) in the analysis of IL occurrence, with ILs considered to be a dynamic and complex system. This may supply added value to policies for environmental repair and protection as well as territorial planning (land use and management), by delimiting possible future areas of IL occurrence. In this regard, IL occurrence was simulated over a long timescale (18 years), to estimate and spatially locate the surface growth of ILs based on CA-Markov and Multiobjective Land Allocation models. The modelling of IL proliferation was divided into three phases: calibration, validation and simulation of the future 2018 scenario. Synchronic data series were used, along with Markov chains and transition rules, in all phases. In the calibration phase the suitability analysis was done and the transition rules and transition potential maps were obtained. The use of dynamic characteristics such as those associated to land uses and static characteristics such as elevation and slope helped model the ILs’ growth. Models’ accuracy was assessed using Kappa index and landscape metrics. Simulation outputs were not highly accurate when reproducing the exact location of ILs, however, they did correctly reproduce the distribution patterns for IL proliferation. Obtaining the best validation results, the CA_Markov model was used to simulating IL proliferation in 2018, predicting that increases of 52.3 ha and 81.5 ha affected by ILs in Zone A and Zone B respectively.
Insight in hydrodynamic properties of submarine flows by the mineral liberation analysis system
Authors: Pszonka Joanna
Published: March 2020

The Mineral Liberation Analysis (MLA) setup is an automated measurement system to provide quantitative data of material features. Originally the MLA system was created and applied to mineralogical and metallurgical processing, however its usage turned out promising for extraction of quantitative data sets in other areas, including sedimentary geology, for example grain size and shape, digital textural maps, porosity, modal mineralogy or mineral associations.

The system is based on a scanning electron microscope (SEM) with an energy dispersive X-ray (EDX) spectrometer and a computer software:

(i)        backscattered electron (BSE) image analysis allows to determine grain boundaries and locations for X-ray spectral acquisition,

(ii)       X-ray spectra allow to classify mineralogical composition of samples by comparison to a library of reference spectra, and

(iii)     software automates microscope operations and data acquisition.

The application of the MLA is useful for collecting textural and mineralogical features of siliciclastic sediments, relevant for assessment of hydrodynamic properties of the flows that deposited them. Moreover, this approach seems to be crucial for analysis of the processes governing difficult to monitor submarine gravity flows, one of the most important sediment transport processes on Earth. Non-linear, non-uniform and unsteady dynamics of submarine gravity flows cause uncertainty in understanding of their nature. Usage of the MLA increases productivity, provides significant statistical representation, reduces human errors and bias as well as tedious manual analyses and is cost effective.
Along-stream evolution of Gulf Stream volume transport and water properties from underwater glider observations
Authors: Heiderich Joleen , Todd Robert E.
Published: March 2020

The Gulf Stream is the western boundary current in the subtropical North Atlantic and a principal component of the upper limb of the Atlantic Meridional Overturning Circulation. Thus, it plays an important role in poleward heat and volume transport, as well as in the redistribution and modification of various water masses. Despite its importance in the climate system, many details of the Gulf Stream’s increase in volume along the US East Coast and the associated entrainment of various water masses are not well known due to a paucity of sustained subsurface measurements within and near the Gulf Stream. Observations from more than 30 Spray autonomous underwater glider missions comprising over 22,000 profiles and more than 180 distinct cross-Gulf Stream transects collected between 2004 and the present fill a 1,500-km-long gap in sustained subsurface measurements; they provide concurrent measurements of hydrography and velocity in and near the Gulf Stream over more than 15 degrees of latitude between Florida and New England. These observations are used to characterize the along-stream evolution of Gulf Stream volume transport including classification by water properties. Remotely formed intermediate waters (i.e., Antarctic Intermediate Water (AAIW) and upper Labrador Sea Water (uLSW)) are significant components of Gulf Stream transport. AAIW is formed at high southern latitudes and enters the Gulf Stream through the Florida Strait, while uLSW is formed through deep convection in the Labrador Sea and encounters the Gulf Stream at Cape Hatteras as the uppermost layer of the Deep Western Boundary Current. Though it is well known where AAIW and uLSW initially encounter the Gulf Stream, their distribution, advection, and modification within the Gulf Stream remain poorly resolved. The extensive glider observations are used to characterize the evolution and intermittency of AAIW and uLSW pathways within and near the Gulf Stream, including effects of near-bottom mixing and the mechanisms by which uLSW crosses isobaths to arrive over the O(1000)-m-deep Blake Plateau south of Cape Hatteras. This first look at Gulf Stream transport by water class and the three-dimensional pathways followed by intermediate water masses within the Gulf Stream provides a reference for global circulation models to replicate.
Numerical study of resonant shallow flows past a lateral cavity: benchmarking the model with a new experimental data set
Authors: Navas-Montilla Adrián , Martínez-Aranda Sergio , Lozano Antonio , García-Navarro Pilar
Published: March 2020

Steady shallow flows past an open channel lateral cavity have been widely studied in the last years due to their engineering and environmental relevance, e.g. for river restoration purposes [1]. Such flows can induce the excitation of an eigenmode of a gravity standing wave inside the cavity, called seiche, which may be coupled with the shedding of vortices at the opening of the cavity. A complete understanding of such phenomenon is necessary as it may determine the mass exchange between the main channel and the cavity [2]. A numerical study of the resonant flow in a channel with a single lateral cavity is herein presented. Five different flow configurations at a fixed Froude number (Fr=0.8), measured in the laboratory [3], are used as a benchmark. Such experiments are reproduced using a high-order 2D depth-averaged URANS model based on the shallow water equations, assuming that shallow water turbulence is mainly horizontal [4]. The large-scale horizontal vortices are resolved by the model, whereas the effect of the small-scale turbulence is accounted for by means of a turbulence model. Water surface elevation and velocity measurements are used for comparison with the numerical results. A detailed comparison of the seiche amplitude distribution in the cavity-channel area is presented, showing a good agreement between the numerical results and the observations. Frequency analysis techniques are used to extract the relevant features of the flow. It is evidenced that the proposed model is able to reproduce the observed spatial distribution of oscillation nodes and anti-nodes, as well as the time-averaged flow field. The coupling mechanism between the gravity wave inside the cavity and the unstable shear layer at the opening of the cavity is also accurately captured.

[1] C. Juez, M. Thalmann, A. J. Schleiss & M. J.  Franca, Morphological resilience to flow fluctuations of fine sediment deposits in bank lateral cavities, Advances in Water Resources,  115 (2018) 44-59.

[2] I. Kimura & T. Hosoda, Fundamental properties of flows in open channels with dead zone, Journal of Hydraulic Engineering 123 (1997) 98-107.

[3] S. Martínez-Aranda, J. Fernández-Pato, D. Caviedes-Voullième, I. García-Palacín & P. García-Navarro, Towards transient experimental water surfaces: a new benchmark dataset for 2D shallow water solvers, Advances in water resources, 121 (2018) 130-149.

[4] A. Navas-Montilla, C. Juez, M.J. Franca & J. Murillo, Depth-averaged unsteady RANS simulation of resonant shallow flows in lateral cavities using augmented WENO-ADER schemes, Journal of Computational Physics, 24 (2019) 203-217.
River water quality modeling using continuous high frequency data allows disentangling whole-stream nitrogen uptake and release pathways
Authors: Huang Jingshui , Rode Michael
Published: March 2020

River water quality models offer studying spatio-temporal variation and processes of nitrogen (N) turnover. However, the infrequent temporal resolution of monitoring data commonly limit the reliability of modeling instream N processing. These limitations of the temporal data resolution can result in equifinality of model parameter sets and considerable uncertainties due to insufficient ability of validating internal turnover processes. The combination of emerging high frequency monitoring techniques and water quality modeling may support continuous quantification of instream N processing pathways with higher reliability.

In this study, we set up a hydrodynamic and river water quality model (WASP 7.5.2) in the 27.4-km reach of the 5th order river Bode in Central Germany for a 5-year period (2014-2018). High frequency data (15-min interval) of discharge, nitrate, dissolved oxygen (DO) and Chlorophyll-a (Chl-a) at the upstream and downstream station were used as model inputs and for model testing, respectively. Chl-a and DO data were used for disentangling uptake via phytoplankton and benthic algae. Furthermore we identified the most important N-removal and release processes including denitrification, excretion from phytoplankton and benthic algae at daily, seasonal and annual scales.

The PBias of lower than 20% between the simulated and measured high-frequency values for the four variables showed general good performance of the model. Results showed that on an annual scale, net N uptake efficiency ranged from 0.2-17.2% and increased with decreasing discharge resulting in highest value for the extreme low-flow year 2018. Among seasons, net uptake efficiency was found to be the highest in summer. Over 50% of the N loading was taken up at the extreme low flow in the summer of 2018. The contributions of each pathway to total N uptake decreased from assimilatory uptake via benthic algae, denitrification, and assimilatory uptake via phytoplankton. However, in the extreme low-flow summer of 2018, the importance of denitrification was largely increased compared to former years. Besides, in autumn, the reach became a net N source, because remineralization of N from benthic algae surpassed uptake processes.

Our study highlights the value of high frequency data to support river water quality modeling allowing continuous quantification of whole-stream N uptake and release pathways.
Deep geophysical investigation in urban area: Ferrara city example
Authors: Rizzo Enzo , Capozzoli Luigi , De Martino Gregory , Piscitelli Sabatino , Bellanova Jessica , Caputo Riccardo , Lapenna Vincenzo , Petronio Lorenzo , Baradello Luca , Affatato Alessandro , Morelli Gianfranco , Fischanger Federico
Published: March 2020

The role of applied geophysics for the new scenario of the increasing global urbanization is going to grow day by day. In this scenario a detailed knowledge of the geological subsoil and its iteration with urban infrastructures became a fundamental issue for urban planning. A novel sub-discipline, called Urban Geophysics (Lapenna, 2017) , has recently been developing in the field of geophysics for analyzing limits and potentialities of well-known geophysical techniques in urban and industrialized areas. The application of some geophysical methods allows the recognition of geological structures from near surface down to more several hundred meters. The urban environment, characterized by a difficult logistic and a high level of noise, has a strong impact on the applicability of the geophysical prospecting methods and on the data quality.

This paper presents the results obtained by Deep Electrical Resistivity Tomography (DERT) and P-wave seismic reflection surveys performed in the city of Ferrara, which is interested in the management of geothermal resources and in the mitigation of seismic risk (CLARA-“Cloud Platform and smart underground imaging for natural risk assessment” Project funded by Italian MIUR). Along the eastern flank of the city walls, DERT and Reflection Seismic profiles were carried out in order to improve the geological information of the urban context.

DERT applications are not very common and there are only few published examples. It consists to inject direct current (square wave) into the ground, depending on the arrangement of the input points and the electrical resistivity of the subsoil, the shape of the electric field that is measured at the surface. The peculiarity of the DERT is the use of large electrode distances (>200 m) and long profiles (>3000 m) in order to reach large investigation depths (>300 m).

Seismic reflection investigations offer a powerful non‐invasive tool suitable for mapping the subsurface geological framework from the very near‐surface to hundreds of metres below surface. Recently several seismic surveys was performed in urban environment by using frequency-controlled vibroseis sources both in P- and SH-wave.

Along the eastern flank of the city walls, a DERT (5500m long) and a reflection seismic (2500m acquired by a MiniVib source in P-wave configuration) profiles were carried out in order to improve the geological information of the urban context. The joint interpretation of DERT and seismic data allowed to reconstruct the 'local' stratigraphic-depositional evolution until a depth of about 1 km, and to highlight the occurrence of a sin-depositional Quaternary tectonic tilting associated to the growth of a fault-propagation fold.
Forest dynamics after drought-induced mortality: a global assessment
Authors: Batllori Presas Enric , Lloret Maya Francisco
Published: March 2020

Forest mortality related to extreme drought has been reported worldwide, affecting all biomes and plant types (angiosperm vs. gymnosperms, evergreen vs. deciduous). The forecasted increased frequency and intensity of drought events as a consequence of anthropogenic climate change could promote an increasingly widespread drought-induced mortality in the future. However, little understanding exists on ecological trajectories or the replacement processes after drought-induced mortality events. We assess (through a collaborative initiative) the extent of short-term self-replacement patterns in temperate forest ecosystems worldwide (N = 131 sites) in relation to: species traits, the major bioclimatic characteristics of reporting sites, and past management and disturbance legacies in the affected sites. We found that alternate species replaced pre-drought dominant tree species in ~70% of the examined cases, whereas in ~10% of the study sites there was no replacement by woody vegetation. Replacement was influenced by management intensity, and post-drought shrub dominance was higher when pathogens acted as co-drivers of tree mortality. No significant replacement patterns were found in relation to the bioclimatic characteristics of the reporting sites (environmental location) or of the dominant species (bioclimatic ‘niche’). Shifts to both more xeric and to moister communities were observed. These changes were driven by species with higher limits of tolerance to dry conditions and by species with wider bioclimatic ranges, respectively. Overall, our findings highlight the potential for major forest ecosystem reorganization in the coming decades.
Validation of tropospheric NO2 columns measurements from GOME-2, OMI and TROPOMI using MAX-DOAS and direct-sun network observations with focus on dilution effects
Authors: Pinardi Gaia , Van Roozendael Michel , Hendrick François , Theys Nicolas , Compernolle Steven , Lambert Jean-Christopher , Valks Pieter , Liu Song , Boersma Folkert , Eskes Henk ,   NIDFORVAL NO2 team
Published: March 2020

Ground-based remote sensing MAX-DOAS and Pandora direct-sun instruments measuring in the UV-Vis spectral region are nowadays widely used to monitor atmospheric NO2 columns. Owing to the multiple geometries used, these techniques can differentiate total, tropospheric and stratospheric NO2 content and  therefore provide an appropriate source of correlative data for the validation of satellite instruments such as GOME-2, OMI and TROPOMI.

In this study we combine ground-based remote sensing correlative measurements available from over 40 sites distributed worldwide to address the validation of GOME-2, OMI and TROPOMI data products. For GOME-2, we concentrate on the GDP operational product generated within the EUMETSAT AC SAF project and on the climate data record generated within the EU QA4ECV project, while for OMI we address both the TEMIS and QA4ECV data products. Regarding TROPOMI, the operational OFFL product is considered. To derive tropospheric NO2 columns from direct-sun total NO2 data, we use estimates of the stratospheric contribution available from each satellite data product.

A negative bias is generally found between the different satellite data products and the ground-based tropospheric NO2 measurements, which is mostly prominent in urban sites characterized by strong localized emission sources (up to about -32% to -45%, e.g. for OMI TEMIS and GOME-2 GDP vs MAX-DOAS ensemble). In an attempt to quantify and correct for the horizontal dilution happening around urban stations (due to diffusion and transport and to the spatial averaging of high resolution structures), we use high-resolution gridded NO2 maps obtained from one year of QA4ECV data. Results from applying this dilution correction show a clear improvement of the agreement between GOME-2 and OMI data at polluted urban locations. Further, the impact of the satellite ground pixel size (GOME-2 40x80km², OMI 13x24km²) and site location is investigated.
Combined Precise Orbit Determination for BDS-2 and BDS-3 Satellites
Authors: Peng Hanbing , Ge Maorong , Yang Yuanxi , Schuh Harald , Galas Roman
Published: March 2020

Since November 2017, the 3rd generation BeiDou Navigation Satellite System (BDS-3) of China has stepped into an intensive build-up phase. Up to the end of 2019, there are 5 experimental and 28 operational BDS-3 satellites in the space. Besides that, 16 BDS-2 legacy satellites are still providing Positioning, Navigation and Timing (PNT) service for Asia-Pacific users. Unlike BDS-2 satellites, BDS-3 satellites will not transmit signal on frequency B2I which is one of the open service frequencies of BDS-2 and will be replaced by B2a of BDS-3. For legacy signals, only that on B1I and B3I will be transmitted by all BDS-3 satellites. Therefore, current routine scheme that generates precise orbit and clock products with B1I+B2I combination observations becomes infeasible for BDS-3. Observation combination used for product generation of BDS-2 could be switched to B1I+B3I combination as well. However, this might cause discontinuity in BDS-2 products as different hardware delays specific to signals are contained in them. In this study, combined processing of BDS-2 and BDS-3 satellites to generate consistent precise orbit and clock products is researched. To elaborate the impact of observation biases between BDS-2 and BDS-3, different combined Precise Orbit Determination (POD) processing schemes are examined. It shows that receiver biases between BDS-2 and BDS-3 should be considered in combined POD which is clear from the post-fit residuals of observations, especially from that of BDS-3 code observations. After estimating those biases between B1I+B2I of BDS-2 and B1I+B3I of BDS-3, Root-Mean-Square (RMS) of BDS-3 code observations decreases from 5.07 to 1.23 m. The results show that, biases of B1I+B3I between BDS-2 and BDS-3 are relatively small, less than 4 m for most receivers and around 1.2 m on average. But their estimates are stable with standard deviations (STDs) of 0.13 ~ 0.34 m depending on receiver types. Influences of these biases on the POD results are limited. However, biases between B1I+B2I of BDS-2 and B1I+B3I of BDS-3 are more significant, from -10 to 30 m for different receivers. Except for Septentrio receivers, quantities of those biases are basically related to the receiver types. Averages of biases from Trimble, JAVAD and Leica receivers are 18.5, 5.0 and 10.0 m, respectively. Those biases are also estimated with very small STDs, which ranges from 0.13 to 0.28 m. It is demonstrated that those receiver biases should be properly handle in combined POD processing of BDS-2 and BDS-3 satellites. As B1I+B2I is more appropriate for BDS-2, using different observation combinations for BDS-2 and BDS-3 in combined POD processing is more preferred over the scheme in which B1I+B3I is used for both BDS-2 and BDS-3.
Atmospheric boundary layer parameters retrieval from Stepped Frequency Microwave Radiometer measurements in tropical cyclones
Authors: Rusakov Nikita , Poplavsky Evgeny , Ermakova Olga , Troitskaya Yuliya , Sergeev Daniil , Balandina Galina
Published: March 2020

Active microwave sensing using satellite instruments has great advantages, since in this range the absorption by clouds and atmospheric gases is noticeably reduced, it allows for round-the-clock and all-weather monitoring of the ocean. One of the main problems is concerned with obtaining the dependency between the RCS of radar signal scattered by the wavy water surface and the parameters of the atmospheric boundary layer in hurricane conditions. To obtain this dependence, we used field measurements of wind speed in a hurricane from falling NOAA GPS-sondes and SAR images from the Sentinel-1 satellite. However, there is the problem of correct collocation of remote sensing data with field measurements of the atmospheric boundary layer parameters, since they are separated in time and space. In this regard, the amount of data suitable for analysis is very limited, which forces us to look for new data sources for processing. A six-channel SFMR radiometer is also installed on board of NOAA research aircraft that measures the emissivity of the ocean surface beneath the aircraft. Thus, it becomes possible to relate the radiometric measurements of SFMR with the parameters of the atmospheric boundary layer in a tropical cyclone obtained from wind velocity profiles, since they are carried out as close as possible in time and space. Using this relation, the SFMR data and the hurricane radar images were analyzed together and an alternative method was found for constructing the dependence of the RCS on the parameters of the boundary layer.

This work was supported by the RFBR projects No. 19-05-00249, 19-05-00366, 18-35-20068 (remote sensing data analysis) and RSF No. 19-17-00209 (GPS-sondes data assimilation and processing).

 
Estimation of Lake Urmia Evaporation from the Combined Ground-based and Satellite Imagery Data
Authors: Abdoli Mohammad , Danesh-Yazdi Mohammad , Arabzadeh Alireza , Javadian Mostafa , Tajrishy Massoud
Published: March 2020

Lake Urmia (LU) has been the second-largest hypersaline lake in the world located in the northwest of Iran that encountered a drastic drawdown in the water level over the past two decades. Accurate estimation of the water balance components, particularly evaporative loss from the water surface as the main component of the LU water budget, is important for the lake water management and restoration programs. In this study, long-term evaporation from the LU surface was estimated between 2000 and 2017 using the Bowen Ratio Energy Balance (BREB), Priestley-Taylor, DeBruin-Keijman, Penman, and Stephans-Stewart methods that leverage meteorological observations and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) satellite earth observation data. The impact of water salinity on evaporation was also considered through dynamic water activity coefficient as well as water density. Given observations from the saline water pan evaporation located in the Lake vicinity, the Debruin-Keijman method yielded the most accurate estimation with the correlation coefficient of 0.93, the root means square error (RMSE) of 121 mm in annual scale. The minimum and maximum annual evaporation were estimated as 783 mm and 1216 mm in 2011 and 2000, respectively, with the annual average evaporation for the entire period, were 1077 mm. By extracting monthly lake surface area from image classification techniques, monthly and annual volumetric evaporation were estimated, indicating that the annual average of the lake volumetric evaporation approximates to 3.6 BCM, which exceeds LU annual environmental requirement water of 3.1 BCM.
Exploring the Growing Role of Terrestrial Carbon Across North Atlantic Fjords
Authors: Smeaton Craig , Austin William
Published: March 2020

Fjords are recognized as globally significant hotspots for the burial (Smith et al., 2015) and long-term storage (Smeaton et al., 2017) of marine and terrestrially derived organic carbon (OC). By trapping and locking away OC over geological timescales, fjord sediments provide a potentially important yet largely overlooked climate regulation service. The proximity of fjords to the terrestrial environment in combination with their geomorphology and hydrography results in the fjordic sediments being subsidized with organic carbon (OC) from the terrestrial environment. This terrestrial OC (OCterr) transferred to the marine environment has traditionally be considered lost to the atmosphere in the form of CO2 in most carbon (C) accounting schemes yet globally it is estimated that 55% of OC trapped in fjord sediments is derived from terrestrial sources (Cui et al., 2016). So is this terrestrial OC truly lost? Here, we estimate the quantity of OCterr held within North Atlantic fjords with the aim of better understanding the recent and long-term role of the terrestrial environment in the evolution of these globally significant sedimentary OC stores. By understanding this subsidy of OC from the terrestrial to the marine environment we can take the first steps in quantifying the terrestrial OC stored in fjords and the wider coastal marine environment.

Cui, X., Bianchi, T.S., Savage, C. and Smith, R.W., 2016. Organic carbon burial in fjords: Terrestrial versus marine inputs. Earth and Planetary Science Letters, 451, pp.41-50.

Smeaton, C., Austin, W.E., Davies, A., Baltzer, A., Howe, J.A. and Baxter, J.M., 2017. Scotland's forgotten carbon: a national assessment of mid-latitude fjord sedimentary stocks. Biogeosciences.

Smith, R.W., Bianchi, T.S., Allison, M., Savage, C. and Galy, V., 2015. High rates of organic carbon burial in fjord sediments globally. Nature Geoscience, 8(6), p.450.

 
Agricultural hydroinformatics: agricultural water systems management as a new application for hydroinformatics
Authors: Celicourt Paul , Gumiere Silvio J. , Rousseau Alain
Published: March 2020

Hydroinformatics, throughout its more than 25 years of existence, has been applied to a set of research areas. So far, these applications include: hydraulics and hydrology, environmental science and technology, knowledge systems and knowledge management, urban water systems management.

This paper introduces agricultural water systems management as a new application for hydroinformatics, and terms it as “agricultural hydroinformatics”. It presents a discipline-delineated conceptual framework originating from the particularities of the socio-technical dimension of applying hydroinformatics in agriculture. It epitomizes the wholeness and inter-dependencies of agricultural systems studies and modelling. It is suitable to support, not only integrated agricultural water resources management in particular, but also agricultural sustainability in general, in addition to a wide range of agricultural development situations beyond connections between agro-economic and water engineering development and its socio-economic impacts.

The paper also highlights some contributions of hydroinformatics to agriculture including new kinds of sensing technologies, information and simulation models development that bear the potential to boost reproducibility of agricultural systems research through systematic and formal records of the relationships among raw data, the processes that produce results and the results themselves.
A baroclinic tidal forecasting model for the Mediterranean Sea - First validation results
Authors: Goglio Anna Chiara , Clementi Emanuela , Drudi Massimiliano , Grandi Alessandro , Lecci Rita , Agresti Valentina , Masina Simona , Coppini Giovanni , Pinardi Nadia
Published: March 2020

In the framework of the Copernicus Marine Environment Monitoring Service (CMEMS) Mediterranean

Analysis and Forecasting Physical System (MedFS), a specific modeling upgrade has been carried out

by including the main lunisolar tides.

Mediterranean tides, even if characterized by small amplitudes, play an important role on the dynamics

of the Mediterranean sea and the introduction of tides in the hydrodynamic numerical model simulations

represent the first step in the development of a numerical forecasting model that considers explicitly the

tidal dynamics and the mesoscales.

MedFS is an operational system that produces weekly analysis and daily 10-days forecasts of the main

physical fields with a resolution of around 4.5km over the whole Mediterranean basin including the

Atlantic Ocean adjacent area (Clementi et al., 2018).

Baroclinic high resolution numerical experiments have been performed including a tidal potential and

forcing the model at the Atlantic boundaries with tidal elevation downscaled from a global model

FES2014 and tidal velocity derived from the TUGOm (http://sirocco.omp.obsmip.

fr/ocean_models/tugo) ocean hydrodynamic model. The experiments have been carried out

including the 8 most relevant tidal constituents in the Mediterranean Sea, namely M2, S2, K1, O1, K2,

N2, P1 and Q1.

In this work, first results of baroclinic tidal model experiments are presented together with their

validation with respect to insitu and satellite data as well as comparing with available literature studies.

In particular the harmonic analysis of tidal amplitudes and phases highlight the model ability to

correctly represent the tide gauges observations in the whole basin and in the areas of large tidal signal.
REVEALS-based reconstruction of Holocene vegetation abundance in temperate China: new insights on past human-induced land-cover change for climate modelling
Authors: Li Furong , Gaillard Marie-José , Sugita Shinya , Cao Xianyong , Herzschuh Ulrike , Zhao Yan , Xu Qinghai , Ni Jian
Published: March 2020

Quantification of the effects of human-induced vegetation-cover change on past (present and future) climate is still a subject of debate. Our understanding of these effects greatly depends on the availability of empirical reconstructions of past anthropogenic vegetation cover. Such reconstructions can be used to evaluate Anthropogenic Land-Cover Change (ALCC) scenarios for the past (such as HYDE and KK), and simulated past vegetation using dynamic vegetation models such as LPJGUESS. In this context, China is an important region given that agriculture started already in early Holocene, and expanded rapidly over large areas throughout the eastern part of the country. Quantitative reconstructions of plant cover based on pollen data has long been a challenge. The REVEALS model (Sugita, 2007) is one of the approaches for quantitative reconstruction of past plant cover that has been applied, tested, and validated in many regions of the world over the last years. Relative pollen productivity (RPP) of plant taxa is a key parameter required for REVEALS applications. A synthesis of all RPP estimates available in temperate China is published in Li et al. (2018). These RPPs were used with pollen records from lakes and bogs to produce REVEALS-based estimates of Holocene regional vegetation-cover change in temperate China. In order to interpret the REVEALS reconstructions in terms of climate or anthropogenic land-cover change, we compared the REVEALS estimates of vegetation-cover change with existing palaeoclimatic data and archaeological evidences on human history and past land-use change. We also compared the REVEALS estimates with fractions of plant functional types simulated by LPJGUESS and ALCC scenarios from HYDE and KK.

The results suggest that the REVEALS-based values of plant cover strongly differ from the pollen percentages and provide new insights on past changes in plant composition and vegetation dynamics over the Holocene. Human-induced deforestation is highest in eastern China with 3 major phases at ca. 5500, 3000 and 2000 calibrated years before present. Disentangling human-induced from climate-induced pollen-based open-land cover remains a challenge. However,  thorough comparison of the REVEALS reconstructions with historical and archaeological information on settlement and land-use history, and with palaeoclimate reconstructions provide important clues to the question. This study is a contribution to PAGES LandCover6k.

References: Li et al., 2018. Front Plant Sci; Sugita, 2007. Holocene.
Hotspots created by earthworms, and their contribution to soil nitrogen cycling
Authors: Whalen Joann , Benslim Hicham
Published: March 2020

Earthworms create hotspots that support microbial diversity and activity in soil. These hotspots may be internal to the earthworm, such as in their intestinal tract, or external to the earthworm in the biopores, casts and middens they create on the soil surface and within the soil profile. This presentation summarizes some of the key hotspots associated with earthworms, and how the biostimulated microbial community in these areas contributes to soil nitrogen cycling. We will present observations about the diversity and activity of nitrogen-cycling microorganisms that live within the earthworm and in its built environments, as well as the population- and community-level contributions of earthworms to denitrification, nitrogen mineralization, and the soil nitrogen supply in temperate agroecosystems.
Solar-related and internal drivers of the northern polar vortex
Authors: Salminen Antti , Asikainen Timo , Maliniemi Ville , Mursula Kalevi
Published: March 2020

During the winter, a polar vortex, a strong westerly thermal wind, forms in the polar stratosphere. In the northern hemisphere the polar vortex varies significantly during and between winters. The Sun and the solar wind affect the polar vortex via two separate factors: electromagnetic radiation and energetic particle precipitation. Earlier studies have shown that increased energetic electron precipitation (EEP) decreases ozone in the polar upper atmosphere and strengthens the northern polar vortex, while solar irradiance affects temperature and ozone in the stratosphere directly at low latitudes and indirectly at high latitudes. In addition to the solar-related drivers, the northern polar vortex is also affected by different atmospheric internal factors such as Quasi-Biennial Oscillation (QBO), El-Nino Southern Oscillation (ENSO) and volcanic aerosols. Several studies have shown that the QBO modulates the effects that the solar-related drivers and ENSO cause to the polar vortex. In this study we examine and compare effects of the two solar-related drivers (solar radiation and EEP) and three atmospheric internal factors (QBO, ENSO and volcanic aerosols) on the polar vortex. We use multiple linear regression analysis to estimate the effects of each factor on temperature and zonal wind. We concentrate on the northern wintertime stratosphere and troposphere and examine the period of 1957-2017 using a combination of ERA-40 and ERA-Interim re-analysis data. We also study these effects separately in the two QBO phases. While we confirm that increased EEP is associated with a strengthened polar vortex, in accordance with the earlier studies, we further show that EEP is the largest and most significant factor among those studied affecting  the northern polar vortex variability. We also find that the EEP effect on polar vortex is particularly strong in the easterly phase of QBO while in the westerly phase the EEP effect is weakened and does not stand out from other effects.
Beyond empiricism: Quantitative models for the permeability of heterogeneous magmas
Authors: Vasseur Jérémie , Wadsworth Fabian , Dingwell Donald
Published: March 2020

Measurements abound for the permeability of volcanic rocks, high temperature magmas, synthetic analogues for magma and rock, and 3-dimensional domains of porous media simulated numerically. Despite a wealth of data, the dominant approach to parameterisation has been empirical, and scarcely goes beyond the power-law models for percolating systems. Here we propose a suite of methods to bring the data for these complex systems in line with theoretically grounded percolation models. To do this we create numerical samples using variations on theme of overlapping spheres filling volumes. In order to create a wide range of possible geometries, we can either define the spheres as the pore phase, or the inter-sphere volume as the pore phase, such that one option is the inverse of the other. In either case, we simulate fluid flow through the pore phase until steady state, to determine the Darcian and inertial permeability tensors. We compare these results with derived, fully theoretical percolation theory and find good agreement without fitting parameters. In order to render this useful for understanding permeability in volcanic scenarios, we compare these validated models to a large database of compiled published permeability data. This approach allows us to group the permeability of magmas into three universality classes, which each have just one dimensionless solution: (1) initially granular magmas, such as variably welded ignimbrites or tuffisites, and (2) bubbly magmas, such as pumice.
Multiyear drought assessment for long term rainfall and river flows in Italy
Authors: Santolini Enia , Lisi Manuela , De Paolis Maria Chiara
Published: March 2020

Long term time series of daily rainfall and daily river flows are
analysed in order to detect the occurrence of drought rich periods
through the application of the theory of runs. In detail, we consider
the time series of the daily rainfall in Bologna (1813-2019) and daily
river flows of the Po River at the closure section (1920-2017). These
data sets are a valuable opportunity to assess long term changes of
precipitation and water resources availability and the effect of recent
climate change. The occurrence of multiyear droughts is a major concern
in the context of Italy for the potential impact on irrigation as well
as water supply for civil and industrial use. The design suitable
adaptation techniques needs to be based on a careful assessment of the
probability of multiyear droughts and their intensity. Our results point
out the occurrence of critical events along the whole span of the
considered observation period, as well as the contingency of a number of
recent droughts that point out a condition of potential vulnerability.