bluuebunny/crossref_metadata_2025 huggingface dataset:
Relevant CMEMS products to predict oil slick drift in the Grande America accident
Authors: Daniel Pierre , Drevillon Marie , Levier Bruno , Gouriou Vincent
Published: March 2020

The Copernicus Marine Environmental Monitoring Service (CMEMS) is a unique capability to provide daily state-of-the-art ocean analyses and forecasts. In the event of accidental marine pollution incidents, those products can help predict where slicks of pollutant and other substances spilled at sea will drift. For a given area, several products are generally available and it is sometimes difficult to know which is the most suitable for this type of use. The use of several CMEMS products during a major accident in the Bay of Biscay is presented here.

On March 12, 2019, the merchant ship Grande America sank at a depth of 4600 m, 350 km off the French coast, in the Bay of Biscay. It caused a spill of bunker oil and loss of containers. The MOTHY drift model was used daily during the aerial surveillance and recovery at sea period. It provided drift forecasts for oil slicks and containers up to 3 days in deterministic mode and up to 10 days in probabilistic mode. Long-term modelling of residual diffused pollution was also carried out, in particular to manage continuous leakage from the wreck. A technical committee of experts met daily to evaluate drift observations and forecasts. It focused on the best choices of available ocean models.

The operational ocean analysis and forecasting systems IBI (Iberian Biscay Irish) at 1/36 degree and Global Mercator at 1/12 degree were used. They led to significant differences in drift predictions, and only one of the two systems was retained after a few days of use. These differences are analysed in the light of available observations.

Drift forecasts did not indicate any oil arrival to the coast. This allowed the authorities to organize the response at sea without mobilizing resources ashore. No pollution was indeed observed on the coasts.
AEOLUS weekly mission planning concept and strategy
Authors: De Laurentis Marta , Fischer Peggy , Mizzi Loretta , Mellano Luca
Published: March 2020

Launched in August 2018, Aeolus is the first remote sensing mission using a Doppler Wind Lidar for the observation of Earth’s wind and air circulation on a global scale. The main instrument ALADIN – Atmospheric LAser Doppler INstrument –  is measuring the atmospheric dynamics in the near-UV at wavelength of 355 nm, receiving back the signal through two different channels for clear air molecules (Rayleigh) and aerosol and clouds particles (Mie).

ALADIN operations are commanded from ground and are a combination of wind acquisitions and in-flight calibrations, for monitoring the instrument health and improving data quality. The mission is based on a planning cycle of 111 orbits, covering exactly one calendar week, for ~16 orbits per day.

The analysis of the weekly mission planning is performed taking into account a number of requirements and constraints at different levels, including platform and instrument system requirements, calibrations measurement performance, NRT data optimisation, science and cal/val requests, and requirements in support to collocated measurement campaigns. Once the analysis is done, the planning is then built into a timeline of consecutive requests for changing measurement mode, using specific instrument parameters tables.

This poster will provide an overview of the Aeolus weekly mission planning concept, strategy and methodology, together with a description of the major operations events for Aladin FM-A and FM-B instruments during the operational phase.
Magnetometer in-flight offset accuracy for the BepiColombo spacecraft
Authors: Schmid Daniel , Plaschke Ferdinand , Heyner Daniel , Mieth Johannes Z.D. , Anderson Brian J. , Baumjohann Wolfgang , Matsuoka Ayako , Narita Yasuhito
Published: March 2020

Recently ESA and JAXXA launched the two-spacecraft mission BepiColombo to explore the plasma and magnetic field environment of Mercury. Both spacecraft, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO, also referred to as Mio), are equipped with fluxgate magnetometers, to provide in-situ data for the characterization of the internal magnetic field origin as well as its dynamic interaction with the solar wind. To achieve this goal, accurate magnetic field measurements are thus of crucial importance, which require proper in-flight calibration. In particular the magnetometer offset, which relates relative fluxgate readings into an absolute value, needs to be determined with high accuracy. Usually, the magnetometer offsets are evaluated from Alfvénic fluctuations observed in the pristine solar wind. However, while Mio's orbit will indeed partially reside in the solar wind, MPO will remain within the magnetosphere at most times during the main mission phase. Therefore, we examine an alternative offset determination method, based on the observation of highly compressional fluctuations, the so-called Mirror Mode Method. To evaluate the method performance in the Hermean environment, we analyze four years of MESSENGER magnetometer data, which are calibrated by the Alfvénic fluctuation method, and compare it with the accuracy and error of the offsets determined by the Mirror Mode Method in different plasma environments around Mercury. We show that the Mirror Mode Method yields the same offset estimates and thereby confirms its applicability. Furthermore, we also evaluate the spacecraft observation time within different regions necessary to obtain reliable offset estimates. Although the lowest percentage of strong compressional fluctuations are observed in the solar wind, this region is most suitable for an accurate offset determination with the Mirror Mode Method. 132 hours of solar wind data are sufficient to determine the offset to within 0.5nT, while thousands of hours are necessary to reach this accuracy in the magnetosheath or within the magnetosphere. We conclude that in the solar wind the Mirror Mode Method might be a good complementary approach to the Alfvénic fluctuation method to determine the (spin-axis) offset of the Mio magnetometer. However, although the Mirror Mode Method requires considerably more data within the magnetosphere, it might also be for the MPO magnetometer one of the most valuable tools to determine the offsets accurately.
Sequence of Heinrich Event 1 to the Bølling-Allerød in transient climate model simulations
Authors: Sun Yuchen , Zhang Xu , Werner Martin , Knorr Gregor , Lohmann Gerrit
Published: March 2020

During the last deglaciation, the North Atlantic was punctuated by evident millennial-scale climate variability – surface cooling during Heinrich Event 1 (H1), followed by abrupt warming during the Bølling-Allerød (BA). Given its abundance of available proxy records, the last deglaciation is thus a perfect testbed for us to assess the triggering dynamics of these abrupt events. Here, a water-isotope enabled, coupled atmosphere-ocean general circulation model COSMOS-wiso (Werner et al., 2016) is applied to test different mechanisms potentially responsible for a BA abrupt warming. First, two sets of experiments are conducted to test the sensitivity to background boundary conditions: one is based on the Last Glacial Maximum (LGM), and the other was 16ka BP background climate. We also consider the spatial distribution of freshwater flux (FWF) forcing. We find that during the LGM a weak freshwater forcing cannot trigger an Atlantic Meridional Overturning Circulation (AMOC) mode transition. However, the same freshwater forcing can rapidly weaken the AMOC at 16ka BP, including an abrupt AMOC resumption in the subsequent one thousand years. Our experiments support the idea that ice volume plays a dominant role in the stability of AMOC during the termination. Furthermore, we explore the impact of different initial fields on the timing of AMOC recovery. Based on the above 16ka hosing experiment mimicking H1, several phases before the AMOC recovery are selected as initial fields, also with different FWF forcing. Our experiments indicate that the larger the FWF forcing, the longer it would take for the AMOC to recover. In all simulations, we detect an overshoot behavior typically for the BA transition. Finally, we implement a transient experiment from H1 to BA with changing GHGs and orbital forcing to explore the mechanisms of the sequence of rapid climate changes during the last termination.

Werner, M., Haese, B., Xu, X., Zhang, X., Butzin, M., and Lohmann, G.: Glacial–interglacial changes in H218O, HDO and deuterium excess – results from the fully coupled ECHAM5/MPI-OM Earth system model, Geosci. Model Dev., 9, 647-670, doi:10.5194/gmd-9-647-2016, 2016.
The low-cost hybrid sorbents for immoblization of dyes: sorbents features characterization
Authors: Solińska Agnieszka , Bajda Tomasz
Published: March 2020

The occurrence of dyes in wastewater is a threat for environment and living organisms. Therefore many studies have focused on investigation of diverse sorption materials to develop effective adsorption methods of removing these organic compounds (Yagub et al., 2014). Among the wide range of materials, the low-cost sorbents such as clay minerals, fly ash or lignite have received unflagging interest. However, the novel approach is to mix low-cost sorbents, clay minerals with fly ash or lignite, which could promote efficiency of removing chemically varied dyes and impact the modification of sorbent mixtures properties. Thus, the aim of this study is to investigate and compare features of hybrid sorbents: halloysite-fly ash, palygorskite-lignite before and after sorption reactions of selected dyes and evaluate influence of modified properties on their sorption mechanism. The obtained reactions’ products, as well as hybrid and selected raw sorbents after reactions, were studied by Fourier-transform infrared spectroscopy (FTIR), thermal analysis (DTA/TG) coupled with the measurement of evolved gases composition by mass spectrometer (QMS). The morphology of raw sorbents was analyzed by scanning electron microscopy (SEM) equipped with an energy dispersive spectrometer (EDS) for elemental microanalysis. The results show that sorbents features, especially the presence of organic functional groups, negative surface charges, have distinct impact on their sorption behaviour. Each componnent of hybrid sorbents affects the efficiency of dyes sorption. The obtained results revealed that mixing of various low-cost sorption materials may present unexpected properties.

 

Acknowledgments.

The studies results have been presented with the partial financial support from the EU project of POWR.03.02.00-00-I038/16-00.

Literature:

Yagub M. T., Kanti Sen T., Afroze S., Ang H.M. (2014) Dye and its removal from aqueous solution by adsorption: A review, Advances in Colloid and Interface Science, 209, p. 172-184.
The linkage of dust cycle dynamics and loess during the Last Glacial Maximum in Europe
Authors: Ludwig Patrick , Schaffernicht Erik J. , Shao Yaping , Pinto Joaquim G.
Published: March 2020

In this work, we present different aspects of the mineral dust cycle dynamics and the linkage to loess deposits during the Last Glacial Maximum (LGM) in Europe. To this aim, we simulate the LGM dust cycle at high resolution using a regional climate-dust model. The simulated dust deposition rates are found to be comparable with the mass accumulation rates of the loess deposits determined from Loess sites across Europe. In contrast to the present-day prevailing westerlies, easterly wind directions (36 %) and cyclonic regimes (22 %) were dominant circulation patterns over central Europe during the LGM. This supports the hypothesis that recurring east sector winds, dynamically linked with a high-pressure system over the Eurasian ice sheet (EIS), are an important component for the dust transport from the EIS margins towards the central Europe loess belt. Our simulations reveal the occurrence of highest dust emission rates in Europe during summer and autumn, with the highest emission rates located near the southernmost EIS margins corresponding to the present-day German-Polish border region. Coherent with the persistent easterlies, westwards running dust plumes resulted in high deposition rates in western Poland, northern Czechia, the Netherlands, the southern North Sea region and on the North German Plain including adjacent regions in central Germany. Further, a detailed analysis of the characteristics of LGM cyclones shows that they were associated with higher wind speeds and less precipitation than their present-day counterparts. These findings highlight the importance of rapid and cyclic depositions by cyclones for the LGM dust cycle. The agreement between the simulated deposition rates and the mass accumulation rates of the loess deposits corroborates the proposed LGM dust cycle hypothesis for Europe.
Testing the effect of crystal growth rate on foraminiferal calcite microchemistry using Sr/Ca of individual day/night bands
Authors: Bonnin Elisa , Spero Howard , Gagnon Alexander
Published: March 2020

The Mg/Ca paleotemperature proxy in planktic foraminifera is one of the most widely-used proxies for sea surface temperature. However, this ratio is not constant throughout the test, varying systematically by several fold independent of temperature between faster and slower growing diurnal bands. This phenomenon has yet to be explained mechanistically, however, changing calcification rates may be a contributing factor. Observing the relationship between calcification rate and trace metal incorporation for multiple proxies at the scale of this banding will allow us to better understand the contribution of kinetic effects to heterogeneity. In this study, we examine Me/Ca ratios on a diurnal cycle in Orbulina universa, utilizing a novel approach based on multiple isotopic spikes that allows us to measure Sr/Ca, Li/Ca and Mg/Ca with the precision of isotope dilution while still maintaining the time resolution of microanalytical techniques. Using independently measured growth rates derived from NanoSIMS measurements of diurnal Mg/Ca heterogeneity, we examine the effect of crystal growth rate on foraminiferal Sr/Ca and Li/Ca.  We observe that Sr/Ca ratios in foraminifera are ~3% higher during the night than during the day, which initially appears opposite to the expected signal based on growth rate. However, we also observe a positive correlation between Sr and Mg in foraminiferal calcite, which falls on the same mineralogical line as the Sr/Ca and Mg/Ca of other biogenic and inorganic calcites. We attribute offsets in calcite composition from this mineralogical relationship to kinetics. Interpreted within that framework, day Sr/Ca ratios appear more affected by kinetics than night Sr/Ca ratios, which is consistent with observed calcification rates. The difference between any given data point and the mineralogical line can be explained by kinetic processes, and correlates with oceanographic properties in cultured foraminifera, which could help separate temperature from growth rate effects in the paleorecord.
Can we predict global patterns of long-term climate change from short-term simulations?
Authors: Mansfield Laura , Nowack Peer , Kasoar Matt , Everitt Richard , Collins William , Voularakis Apostolos
Published: March 2020

Furthering our understanding of regional climate change responses to different greenhouse gas and aerosol emission scenarios is pivotal to inform societal adaptation and mitigation measures. However, complex General Circulation Models (GCMs) used for decadal to centennial climate change projections are computationally expensive. Here we have utilised a unique dataset of existing global climate model simulations to show that a novel machine learning approach can learn relationships between short-term and long-term temperature responses to different climate forcings, which in turn can accelerate climate change projections. This approach could reduce the costs of additional scenario computations and uncover consistent early indicators of long-term climate responses.

We have explored several statistical techniques for this supervised learning task and here we present predictions made with Ridge regression and Gaussian process regression. We have compared the results to pattern scaling as a standard simplified approach for estimating regional surface temperature responses under varying climate forcing scenarios. In this research, we highlight key challenges and opportunities for data-driven climate model emulation, especially with regards to the use of even larger model datasets and different climate variables. We demonstrate the potential to apply our method for gaining new insights into how and where ongoing climate change can be best detected and extrapolated; proposing this as a blueprint for future studies and encouraging data collaborations among research institutes in order to build ever more accurate climate response emulators.
Tracing leaf litter-derived 15N to mineral soil organic matter in forests of different ages
Authors: Fuss Colin , Lovett Gary , Goodale Christine , Ollinger Scott , Lang Ashley , Ouimette Andrew
Published: March 2020

Forest soils are important for retaining nitrogen (N), especially in areas where anthropogenic activities have led to historically high inputs of N. As forests age and their N demands for biomass accumulation decline, the capacity for N retention of soils may change as well, although little work has been done to further our understanding of this process. We conducted a mineral soil reciprocal transplant study in three northern hardwood forests of different ages (young, recently mature, and old growth) in New Hampshire, USA to determine how the retention of isotopically labeled nitrogen from leaf litter would differ depending on characteristics of the incubated soil’s origin and destination. After 18 months of incubating the soil bags below the 15N-labeled litter, we did not find retention of litter-derived N to be related to the age of the incubation site forest, but rather that it differed based on the origin of the incubated soil.  We found that the soil C content was the strongest predictor of how much of the tracer was recovered in the transplanted soil bags. Furthermore, the C content of soils changed during incubation and tended to change in the direction of equilibrating with the soil C concentration of the incubation site. This finding suggests that site characteristics are important in determining soil C concentrations and consequently N retention capacities.
Estimate of the D/H ratio in the Martian upper atmosphere from the low spectral resolution mode of MAVEN/IUVS
Authors: Chaufray Jean-Yves , Mayyasi Majd , Chaffin Michael , Deighan Justin , Bhattacharyya Dolon , Clarke John , Jain Sonal , Schneider Nick , Jakosky Bruce
Published: March 2020

The recent observations performed with the high-resolution “echelle mode” by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission indicated large deuterium brightness near Ls=270°. The deuterium brightness observed at the beginning of the mission, when Mars was close to its perihelion show brightness ~ 1 kR much larger than the first deuterium detection from Earth ~ 20-50R in 20-21 January 1997 (Ls = 67°). This low brightness of the deuterium emission is consistent with the lack of deuterium observation with the echelle mode of IUVS at solar longitudes around aphelion (Ls = 71°). During southern summer (Ls = 270°), especially near the terminator, the Lyman-α emission observed at 121.6 nm with the “low resolution mode” presents some vertical profiles that were not reproducible with models including only the emission from the thermal hydrogen population. In this study, we investigate the possibility to derive quantitative information on the D/H ratio at Mars from the vertical Lyman-α profiles observed with the “low resolution mode”, and the main limits of the method.
Technics, science and management related to the evolution of water supply network of La Rochelle city, France, from 1864 to 1913.
Authors: Moreau Frederique
Published: March 2020

The water issue, as vital element to be protected, is central in all societies, including those where water may seem plentiful. With the conscience of the fragility of this resource, the need to question the evolution of the perception of water over time, of the various means used to exploit and preserve it, of scientific knowledge, currently appears as an essential aid to the decision for its preservation.

In many countries, XIXs century was the time of major progress in the construction of water supply networks of cities. Particularly in France, this progress was spured by an hygienist discourse in a context of increase city population, inducing a social demand whose national and local governments seized.The autority of the engineers of the « corps des Ponts et Chaussées » who were in charge of the technical realisation of the cities water network was also an important support in this progress, especially because they also participated at the great evolution of the scientific formulation of fluids mechanics applied to groundwater hydraulic like Henry Darcy (1803-1858) or Jules Dupuit (1804-1866). The latter is also well known as an economist. One of his thoughts is to relate the progress of science to an economic perspective. According to him, « The only difference between the [Roman water ] distributions and those which would be made according to a sound theory and with the best practical procedures is entirely in the expenditure.”

In this study, technical, scientific and management aspects of the evolution of the water supply network of La Rochelle (France ) during the XIXs century are investigated from archives documents. The survey of the conditions for setting up the network of a particular city is a gateway to address all the points cited above. This coastal town, which has a long history and whose port is famous, experienced three stages of improvement of its water network, in 1864, 1883 and 1913. The first step coincides with the development of water supply network of many french towns, the second with the discovery of a new aquifer useable for water supply of the city, and the third one, remained at the state of a project due to the first World War, had been planned in response of the increase of water consumption linked both to the growing of the population and to the new ease of access to water.

This historical knowledge is necessary to understand the spatial and time evolution of the customary practice of water and could be used to draw one’s inspiration from the past efficient solutions that have sometimes be forgotten and that could be reemployed.
Constructing stage discharge relationship with numerical simulation including hydraulic resistance
Authors: yorozuya atsuhiro
Published: March 2020

A flood risk assessment has implemented with an inundation map or with other simulated results; e.g., a rainfall-runoff simulation. In order to conduct the flood risk assessment, it is usual that the case with maximum floods are subject for discussion. At the same time, it is usual that observed data of the maximum floods are not available, since the maximum floods has not experienced, or observation have not conducted. Estimation of the discharge values are not simple, since the river flow at the targeted cross section are affected by river shape, or roughness changes. Both of them are sensitive with different flow stage.

The present study discusses about constructing the stage discharge relationship with numerical simulation. For this purpose, the author implements the 2-D depth integrated flow simulation including the flow resistance. The flow resistance is one of the traditional studies of the sediment hydraulics. It deals with the changing of resistance with different micro-scale bed forms as the bed shear stress changes. Similar with the one by Engelund (1966), the relationship with grain shear stress and total shear stress are constructed in qualitative manner by Kishi and Kuroki (1973). It is useful to obtain the bed roughness with different flow stage. The author implements the changes of the roughness in the 2-D depth integrated flow simulation and obtains the flow field in actual river flow in order to obtain the discharge values.

The authors conducted the numerical simulation in steady flow condition. In order to construct the stage-discharge relationship based on the results, 10 different cases with appropriate ranges of stage were conducted. The domain of the simulation is 5 times longer than the width of the targeted section. In order to construct the initial condition, bathymetry data in the one point in 5 m with the laser technique, and sediment size distribution at the different location; e.g., at center of flow, top of the dune and etc., were obtained. The calculated results were compared with observed flow field by float measurements and other non-contact current meter. The results indicate that the numerical stage-discharge relationship shows some good agreements and few disagreements with the one created based on observation. For example, at the water stage which represents the dune I, the simulated results are similar with observed. However, at the stage of dune II, simulated velocity shows smaller velocity than observed. As Hirai (2015) suggested, shape of micro-bed form classified as Dune II is unstably changes between Dune and flat bed. Therefore, velocity at the stage is sensitively changes as well. From this aspect, the authors concluded that not only the numerical simulation but also field measurement are necessary in order to construct good stage-discharge relationships, in particular if the shear stress at the targeted discharge involves the Dune II.
Metamodeling for predicting drainage fraction in groundwater: Development of a decision-support tool
Authors: Bjerre Elisa , Lajer Højberg Anker
Published: March 2020

Diffuse nitrogen pollution is a major cause of degraded water quality in rivers and groundwater across Europe. In artificially drained agricultural catchments, nitrate leaching from the root zone is either transmitted directly to streams by tile drains or transported to the groundwater system. Thus, the partitioning of the water flux to drains, the drainage fraction, is an indicator of surface-water/groundwater vulnerability to nitrogen application. This information can be used to target mitigation measures like drain filter technologies and cover crops. Hydrological models are usually employed to assist water management. Yet, for many decision-making applications numerical models are computationally too time-consuming. Additionally, as models are simplifications of the complex natural system, model results are inherently imprecise for grid-scale, and thus field-scale, predictions. To overcome these barriers, we develop metamodels to make predictions of drainage fraction. We train random forest and gradient boosted regression trees statistical metamodels to MIKE SHE-derived 16-year averages of drainage fraction in a regional groundwater model (100x100m) in Denmark. We explore the effects of mappable and non-mappable predictor variables on model performance. The metamodels are used to identify the most important predictor variables for drainage fraction prediction. Based on this, we investigate how grid cells of similar characteristics can be clustered in homogeneous subsets, in which the drainage fraction variability can be used as an uncertainty estimate. The findings could potentially support decision making on spatially differentiated regulation of nitrate emissions.
Impact of SST on the development of the cold surges over East Asia
Authors: Lee Hye-young , Kim Joowan
Published: March 2020

This study investigates synoptic characteristics of the cold surges over South Korea during winter season (December-February). A total of 61 cold events are selected by quantile regression analysis using daily mean temperature observations from 11 surface stations for 38 years(1981–2018). Composite analyses reveal that a synoptic-scale cyclone developing over the northern Japan is a key feature that significantly contribute to the enhancement of cold advection by increasing pressure gradient over the Korean peninsula. Enhanced sensible and latent heat fluxes are observed over the southern ocean of Korea and Japan during the cold surges due to increased temperature and humidity differences between the lower atmosphere and ocean surface. These fluxes are transported toward the center of the surface cyclone and help the development of the surface cyclone by inducing positive PV in the lower atmosphere. These processes make a positive feedback loop that amplifies strength of the cold surge. To examine how sea surface temperature (SST) affects the strength of cold surge, we categorize the cold surges into warm, normal and cold SST cases. As a result, stronger and more pronounced cyclones are observed in cases of warm SST. Thus, the positive feedback process particularly enhanced when SST is warmer in the early winter.
Investigating blue water response to green management in a Mediterranean headwater catchment
Authors: Latron Jérôme , Moreno de las Heras Mariano , Molina Antonio , Gallart Francesc , Cervera Teresa , Baiges Teresa , Garcia Joaquim , Borràs Gabriel , Munné Antoni , Manzano Andreu , De Cáceres Miquel , Llorens Pilar
Published: March 2020

Although forest provides multiple ecosystem services (e.g., soil conservation, carbon sequestration, regulation of water cycle), it often cannot provide all of them simultaneously because of the trade-offs between some of them. In particular, while afforestation and reforestation have been recommended as a means of sequestering carbon in forest biomass and soils to limit climate change impacts, these practices may significantly alter streamflow and groundwater recharge, particularly in Mediterranean headwater catchments. In this context, a better understanding of forest hydrology is necessary to anticipate the undesirable trade-offs of forest management that can affect water resources.

Within the MASCC and LIFE + CLIMARK projects, which respectively aim to establish possible land cover scenarios for the next decades and to implement forest management practices to strengthen the capacity of the forest to mitigate the effects of change climate, the Vallcebre research catchments (North Eastern Spain) were selected as a reference site to assess the effect of forest (green) management on water resources (blue water) in a Mediterranean environment. These research catchments offer available medium-term (15 years) hydrological series (precipitation, discharge and water table) prior to forest management and a detailed knowledge of their hydrological response, essential for this evaluation.

In October 2018, the forest cover of a small sub-catchment (0.0248 km2) which initially represented 54% of the basin was thinned (removing between 35% and 60% of the basal area depending on the locations) to assess the effect of multifunctional forest management on streamflow. In the same way, the forest covering the contribution areas (0.0138 and 0.0139km2) of two shallow piezometers was thinned according to the same procedure to evaluate possible changes on the dynamics of the piezometric levels.

This work aims to present the general framework of the study, the type of forest management carried out as well as a first analysis (at different temporal scales) of the water table and discharge dynamics observed during the first year after the forest management.
On the use of different approaches based on photochemical reflectance index and surface temperature to monitor the water status of winter wheat in semi-arid regions
Authors: Rafi Zoubair , Le Dantec Valérie , Merlin Olivier , Khabba Said , Mordelet Patrick , Er Raki Salah
Published: March 2020

Agriculture is considered to be the human activity that consumes the most mobilized water on a global scale. However, crops planted in semi-arid areas regularly face periods of moderate to extreme water stress. Such water stress periods have a considerable impact on the seasonal yield of these crops. In order to participate in a more rational irrigation water management, monitoring of the rapid changes in plant water status is necessary. For this purpose, the combination of two different wavelength ranges will be explored : an index based on Xanthophyll cycle (Photochemical Reflectance Index, PRI) and a commonly-used index from thermal infrared spectral range (LST). An experiment on winter wheat was carried out over two agricultural campaigns (2016 to 2018) in the Haouz basin, which is located in the Marrakech region, to better assimilate the temporal dynamics of PRI and surface temperature. In this study, four different approaches are proposed to study the functioning of wheat : 1- an approach based on solar angle to remove the structure effect (PRI0) from the PRI signal and to derive a water stress index PRIj, 2- an approach based on global radiation (Rg) to extrapolate a theoretical PRI (PRIth) for Rg equal to zero and to calculate a water stress index PRIlin, 3- an approach that determines an optimal PRI (PRIpot) on the basis of the available water content (AWC) criterion in order to derive a stress index I-PRI and 4- an energy balance approach to extract dry and wet surface temperatures in order to establish a normalized surface temperature index (Tnorm). The results of this work show a strong correlation between the PRI0 and the Leaf Area Index with a coefficient of determination equal to 0.92, indicating that it is possible to isolate the structural effects of wheat on the PRI signal. In addition, over the range of variation in AWC, a significant correlation with PRIj, PRIjlin and I-PRI was observed with coefficients of determination of 0.71, 0.42 and 0.24, respectively. In contrast to the Tnorm, which varies only for values of AWC below 30%, a coefficient of determination of 0.22 is obtained. Finally, the PRI allows us to acquire early and complete information on the response of wheat to change in AWC as opposed to the surface temperature index, revealing the potential of the PRI to monitor the water status of plants and their responses to changing environmental conditions.
Intercomparison of Surface broadband Albedo products from MODIS, CGLS over Northeast Asia
Authors: Seong Noh-Hun , Choi Sungwon , Jin Donghyun , Jung Daeseong , Han Kyung-soo
Published: March 2020

Surface broadband albedo is one of the climate variables that understand Earth’s radiation budget. Currently, the polar-orbit satellite-derived surface broadband albedo products are retrieved by several organizations. As there are many kinds, it is necessary to identify the characteristics of each products. In this study, we were to compare representative products for long-term that the albedo products based on polar-obit satellite such as moderate resolution imaging spectroradiometer (MODIS) and the Copernicus Global Land Service (CGLS). We studied the Northeast Asia region where the land type remains unchanged from 2000 to 2018. The overall trend of the two products was similar. However, differences occurred depending on the land types and season. The relatively high value of MODIS albedo was calculated in winter because it was sensitive to the snow. In other seasons, the CGLS albedo was higher than the MODIS albedo. The MODIS albedo was calculated higher than CGLS albedo for all land types except forest. The comparison results showed that caution should be given before operational use of the albedo data sets in these regions.
Validation and characterisation of the Sweeping Langmuir Probe (SLP) instrument for the PICASSO mission
Authors: Ranvier Sylvain , Anciaux Michel , Lebreton Jean-Pierre , De Keyser Johan
Published: March 2020

The Sweeping Langmuir Probe (SLP) instrument, that uses a novel measurement technique to take into account spacecraft charging effects, has been developed at the Royal Belgian Institute for Space Aeronomy. SLP will fly on board the ESA scientific in-orbit demonstrator PICASSO together with the hyper-spectral imager VISION. PICASSO, a triple unit CubeSat, will be launched in March 2020. The goal of the mission is to prove the feasibility of performing true science (with limited extent) with a nano-satellite and demonstrate the very low cost / science ratio with respect to big missions. SLP will allow a global monitoring of the ionosphere with a maximum spatial resolution of the order of 150 m.  The main goals are to study the ionosphere-plasmasphere coupling, the subauroral ionosphere and corresponding magnetospheric features together with auroral structures and polar caps, by combining SLP data with other complementary data sources (space- or ground-based instruments). SLP can measure plasma density from 1e8/m³ up to 1e13/m³ and electron temperature up to 15 000 K.

We will present the main results from the validation tests performed in the plasma chamber at ESTEC together with comparisons with particle-in-cell (PIC) simulations performed with SPIS (Spacecraft Plasma Interaction System).
Using the adjoint state variable for parameter estimation by inverse methods with parsimony.
Authors: Ackerer Philippe , Delay Frédérick
Published: March 2020

Since the pioneer work of Emsellem and de Marsily (WRR, 1971), many parameter estimation methods by inverse methods in hydrogeology are based on the minimization of an objective function using descent methods, which requires the computation of the gradient of an objective function. In many cases, the number of parameters to be estimated is large despite parameterization, and the standard computation of the gradient components by sensitivity coefficients may require a lot of computer time. An alternative is the computation of the adjoint variables which require a calculation similar to the forward problem, irrespective of the number of sought parameters.

The computation of the adjoint variable is usually embedded in the code used to compute the state variable. We discuss here an alternative that consists in (i) write the partial differential equation for the adjoint variable, (ii) writing an independent code for the adjoint variable, (iii) solved the adjoint problem on an independent mesh, different of the mesh used to compute the state variable with coarser time and space discretization to speed up the computation of the adjoint variable. We will present the methodology and discuss the use of coarser discretizations since coarser discretization can impact the accuracy of the computed gradients and lead to additional iterations to reach the objective function’s minimum.
Model Calculations on the Influence of Charged Mesospheric dust on the Incoherent Radar Spectrum
Authors: Gunnarsdottir Tinna , Mann Ingrid , Miloch Wojciech
Published: March 2020

Detection of charged dust in the spectrum of incoherent radars has previously been proposed and examined to some degree. These dust particles are of nanometer size and reside at mesospheric altitudes due to incoming ablating meteors. They are difficult to detect and thus their influence on atmospheric processes is hard to determine. Theoretical studies suggest that charged nanometer sized dust in the mesosphere can be successfully detected in the radar spectrum. However, current radar systems like EISCAT are not capable to distinguish adequately the dust signal from the main signal because the influence is small. We expect however, that the upcoming new EISCAT_3D radar will improve the observation conditions. We here present model calculations to examine the influence of the charged dust component on the radar signal, a so-called dusty plasma effect. Instead of the previously assumed one size dust component, we simulate the incoherent scatter spectrum including a large set of dust size bins. We show that different sizes, number density and charge of dust influence the signal in different ways, either causing a narrowing or broadening of the spectrum. Here the results are presented in a systematic way and specific conditions identified that provide the largest chance of dust detection in the signal. A simple charging model is used to model the most probable charge and altitude dependence to simulate realistic dust distributions that are then used as input to the radar spectrum model. These results can then be used to compare with actual radar measurements. Off which the new EISCAT_3D radar system, ready in 2022, might provide the adequate resolution for these requirements.
Flood emergencies and hydrological science communication
Authors: Cloke Hannah
Published: March 2020

Flood emergencies are a cauldron of politics, media, operational agencies working hard on the ground and of course people’s lives, livelihoods, property and wellbeing put at risk by floodwaters.  Government and humanitarian agencies need to rapidly understand the gravity of a situation and their options to respond. To help them make decisions, and to ensure these decisions are based on evidence and not speculation, they often draft in advisory groups made of up experts in relevant fields. For floods this could include engineers, flood and weather forecasters, agricultural economists or land owners. For a hydrologist, being asked to advise governments in an emergency situation is scary and exciting, but also a wonderful opportunity to put your scientific expertise to use helping people. The key skill in these situations is understanding how and when to speak up. You must speak clearly, use simple language that non-scientists can understand, and you often only have a few seconds to convey your points. You may be faced with opposition, yet you must rely on your training and expertise to make rapid judgements and to point to the best evidence available.  Using real-life examples from flooding crises in the UK, Africa and elsewhere, we will see how it is possible to use scientific skill to directly help people by influencing decisions. By working with governments, emergency agencies and NGOs, scientists can help them to make best use of resources and even save lives.
Spatio-temporal temperature and precipitation patterns in the southern Peruvian Andes - insights from the Climandes project
Authors: Spirig Christoph , Stefanie Gubler , Grinia Avalos , Adrian Huerta , Noemi Imfeld , Waldo Lavado , Clara Oria , Karim Quevedo , Mario Rohrer , Simon C. Scherrer , Katrin Sedlmeier , Cornelia Schwierz
Published: March 2020

In the southern Peruvian Andes, climatic threats such as water scarcity or frost pose major challenges for agriculture. Such events may result in severe yield losses threatening the livelihood of smallholder farmers due to missing adaptive and coping strategies. Knowledge on climate variability and change, on the current state of the climate, as well as short- to midrange predictions potentially improve the farmers’ risk management. However, such knowledge is only partly available and often does not reach rural communities. Climandes, a pilot project of the Global Framework for Climate Services, tackled these shortcomings through the enhancement of climatological observations, the production of gridded datasets using satellite and station observations, the verification of seasonal forecasts to determine their usefulness for small-scale applications, and through the establishment of communication channels and user engagement. This contribution highlights some of the insights from the Climandes project: climatological analyses of spatio-temporal patterns in the southern Peruvian Andes, past trends, as well as the performance of seasonal forecasts in the region. The work focuses on temperature and precipitation using the newly developed gridded datasets, quality controlled observational data, and seasonal forecasts of ECMWF SEAS5.

The results of the climatological analysis let us draw the conclusion that precipitation and minimum temperature patterns are likely related through increased / reduced cloud cover and increased / reduced incoming longwave radiation. Both variables show similar spatial patterns for example in austral spring (SON), namely a pronounced northeast / southwest gradient. Trends, which were derived from the enhanced climatological observation data available since 1964, show a strong increase in maximum temperature of around 0.2°C / decade, while minimum temperatures show only very moderate trends. In addition to the slight decrease of total precipitation in austral spring, i.e., the time of sowing, the strong increase of maximum temperatures further decreases soil water availability and enhances drought risk. With regard to seasonal predictions, we found that especially the performance of precipitation forecasts is only very limited in the southern Peruvian Andes, and mostly does not exceed information from climatology. We conclude that seasonal predictions are not applicable for small-scale applications in the region, whereas they may serve as a beneficial basis to assess climate variability and discuss decision-making based thereon.

 
Data management and analysis of the high-resolution multi-model climate dataset from the PRIMAVERA project
Authors: Seddon Jon , Stephens Ag
Published: March 2020

The PRIMAVERA project aims to develop a new generation of advanced and well evaluated high-resolution global climate models. An integral component of PRIMAVERA is a new set of simulations at standard and high-resolution from seven different European climate models. The expected data volume is 1.6 petabytes, which is comparable to the total volume of data in CMIP5.  

A comprehensive Data Management Plan (DMP) was developed to allow the distributed group of scientists to produce and analyse this volume of data during the project’s limited time duration. The DMP uses the approach of taking the analysis to the data. The simulations were run on HPCs across Europe and the data was transferred to the JASMIN super-data-cluster at the Rutherford Appleton Laboratory. A Data Management Tool (DMT) was developed to catalogue the available data and allow users to search through it using an intuitive web-based interface. The DMT allows users to request that the data they require is restored from tape to disk. The users are then able to perform all their analyses at JASMIN. The DMT also controls the publication of the data to the Earth System Grid Federation, making it available to the global community. 

Here we introduce JASMIN and the PRIMAVERA data management plan. We describe how the DMT allowed the project’s scientists to analyse this multi-model dataset. We describe how the tools and techniques developed can help future projects.