bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of vermicompost and pelleted manure as amendments on chemical and biochemical properties of soil under greenhouse farming
Authors: Coppola Giuseppe Paolo , Di Rauso Simeone Giuseppe , D'Ambrosio Gennaro , Vairo Francesco , Caputo Michele , Amalfitano Carmine , Zaccardelli Massimo , Rao Maria A.
Published: March 2022

Soil organic matter (SOM) plays an important role in conservation and restoration of soil fertility, as it is able to ameliorate physical, chemical and biochemical soil properties preventing erosion, increasing porosity, water-holding capacity and cation exchange capacity. Furthermore, SOM can stimulate microbial biomass and as consequence microbial activity and functionality in terms of soil respiration and enzymatic activities. Biogeochemical cycle of nutrients can also take advantages from the microbial activity enhancement with positive effects on N and P uptake and crop yields. The intensive farming systems favour the SOM decomposition and depletion due to the absence of rotations, the preference of milling to ploughing, the mineral fertilization, and the removal of crop residues.

The aim of this research was to assess the effect of vermicompost (VC) as organic soil conditioner compared to pelleted manure (PM) under greenhouse in a conventional farm. Two doses of VC and PM corresponding to 75 and 150 kg N ha-1 year-1 were applied to solarized soil. Solarization was carried out during the hottest summer period and applied to all plots to control weeds, nematodes and soil-borne pathogens. VC is the final product of a vermicomposting process involving synergistic action of earthworms and microbes in the bio-conversion of organic matter into humus-like substances. VC used in this research derived from solid digestate obtained in anaerobic digestion plant using, as carbon source, livestock sewage, olive mill wastewater and whey from dairy industry. Chemical and biochemical properties of soils sampled after 7 and 150 days from organic amendments were investigated to understand the correlation between the use of organic soil conditioners and organic C stock, nutrient availability, microbial biomass, enzymatic activity, and crop yields and quality.

In the first sampling PM increased significantly the soil electrical conductivity compared to VC amendments. In addition, PM, in particular the greater dose, enhanced better than VC soil respiration, microbial biomass and overall enzymatic activities because PM is richer in labile carbon source than VC. In contrast, VC was able to improve the activity of acid phosphatase and urease by increasing the applied dose thus making free phosphate and ammonium from organic matter.

This study is part of the project "Sustainable management of soil fertility in the Sele Plain to produce ready-to-eat food as cover crops through organic amendment deriving from local livestock sector" funded by PSR Campania 2014/2020.
The use of robotized inclinometric system in Early Warning System. The case study of a large landslide monitoring.
Authors: Godone Danilo , Allasia Paolo , Baldo Marco , Guenzi Diego , De Polo Fabio
Published: March 2022

Geohazard monitoring is a key component in an early warning system (EWS). The implementation of monitoring actions provides data for the acquisition of variables related to the landslide, its triggering and kinematic; additionally, it can provide insights of its evolution in time in order to plan mitigation actions, including alarms and warnings. The use of high-frequency systems can also provide such data in the shortest time thus optimizing the aforementioned actions. In the last decades, numerous surface monitoring systems were developed, with various features, providing punctual information, like GNSS or Robotized Total Stations, at high frequency or large-scale data, i.e. Remote Sensing, at lower temporal resolution. The choice of the best one is related to the goals to be fulfilled but, independently from the selected method, surface techniques monitor only a displacement resulting from the sum of all the deep-seated ground deformations. To properly detect the subsoil behavior of a landslide, the use of subsurface sensors is necessary. To couple the subsoil survey with high frequency monitoring a robotic inclinometric system was developed, and patented, by the Geohazard Monitoring Group (GMG) of CNR-IRPI. The instrumentation features the operational characteristics of the manual inclinometric measures (reliability, double readings 0/180˚…) but integrates the advantages of the robotization (accuracy, measurement frequency…), too. The robotized instrumentation also called “Automated Inclinometer System” (AIS) allows the automatic exploration of all the borehole length (up to 120 meters in the standard configuration) with a single probe. The AIS is remotely connected by a 4G modem so it is possible to define the acquisition parameters, download measured data and check the device functioning parameters. The instrumentation was deployed, at the beginning of December 2021, in a borehole located in Passiria Valley (northeastern Italy) to monitor a large and slow-moving landslide involving the whole mountain face; thanks to instrumentation modularity, the AIS is ready to measure after only 4÷5 hours of installation time. Concurrently with the main installation, a GNSS benchmark was positioned and surveyed to provide, with the next measurement campaigns, a crosscheck with the AIS results. After 10÷15 days of monitoring at 1 measurement/day the landslide’s sliding surface, its depth and deformation rate, were clearly identified, thus confirming the capability of the AIS to perform early detection of the landslide kinematic. This result is key information in the risk reduction chain as it shortens the time necessary to achieve the numerical parameters describing the landslide and, consequently, plain the following, mitigating, actions.
Source Mechanisms of Deep Long Period Earthquakes beneath the Klyuchevskoy Volcano Group (Kamchatka, Russia) inferred from S-to-P amplitude ratios 
Authors: Galina Natalia , Shapiro Nikolai
Published: March 2022

Long-period earthquakes and tremors are one of two main classes of volcano-seismic activity. Deep long-period (DLP) earthquakes are of particular interest because usually they are attributed to the processes occurring in the deep magma reservoirs close the crust–mantle boundary. The physical mechanism of generation of these earthquakes is still not fully understood. The hypotheses of the DLPs origin include thermomechanical stresses associated with cooling of deep intrusions, rapid CO2 degassing from the oversaturated basaltic magmas, and secondary boiling.

In this work, we study the long-period earthquakes that occur at the crust-mantle boundary beneath the Klyuchevskoy volcano group in Kamchatka in order to reconstruct their source mechanism. We considered three possible sources (single force, shear slip and tensile crack) that can produce DLPs. With given hypocentral location and radiation patterns we calculated synthetic seismograms for each of assumed mechanisms. Then, we compared obtained signals with real records measuring amplitudes of P and S waves at each channel and calculating their ratios. For each of he considered types of mechanisms, we perform a grid search in the parameter space and found an optimal solution that minimizes the misfit between the observations and the model predictions.
Effects of data assimilation on different fluxes of a fully coupled land surface/subsurface model
Authors: Waldowski Bastian , Neuweiler Insa , Sánchez-León Emilio
Published: March 2022

We test the improvement of flux predictions with data assimilation (DA) in a coupled land surface/subsurface model. We present results of DA experiments in an idealized testcase with an extent of 1km x 5km x 50m. Our model considers multiple heterogeneous soil units, different plant functional types and a sophisticated topographical design chosen to induce lateral flow and rivers at specific areas. We use TSMP-PDAF to couple the land-surface model CLM and the subsurface/surface flow model ParFlow with the DA framework PDAF. We use a Localized Ensemble Kalman Filter (LEnKF) with an ensemble of 93 members. We consider uncertainty in the atmosphere, soil properties and initial conditions by different atmospheric forcings, distinct heterogeneous soil parameter distributions and an individual spinup for each ensemble member. The ensemble, which has a horizontal grid resolution of 40m, is updated with virtual measurements from a high resolution (10m) reference model.
In the scope of this work, we address the impact of updating different state variables (soil moisture and pressure head) on groundwater recharge, lateral subsurface flow, surface runoff, and evapotranspiration. While surface runoff and evapotranspiration directly depend on pressure head and soil moisture, subsurface flow depends on pressure head gradients. For groundwater recharge, our estimate depends on groundwater storage changes (which can directly be enforced by the updates during DA) as well as subsurface flow. To investigate if DA can directly improve these fluxes, we run multiple experiments with different observation frequencies and localization radii. Further, we investigate if there are improvements in the fluxes during open loop forecasting periods subsequent to DA.
Diversity in NAO-AMOC interaction on interannual to decadal timescales across CMIP6 models
Authors: Reintges Annika , Robson Jon , Sutton Rowan , Yeager Stephen
Published: March 2022

The variations of the winter climate in Europe are influenced by the North Atlantic Oscillation (NAO). Therefore, the ability to predict the NAO is of great value. Predictability of the NAO can be enabled through oceanic processes that are characterized by relatively long time scales, for example interannual to decadal. An important variable for the interannual to (multi-)decadal variability in the North Atlantic is the Atlantic Meridional Overturning Circulation (AMOC). The NAO and the AMOC are known to interact, but observational records of the AMOC are short and the details of this interaction are unknown. Thus, our understanding largely relies on climate model simulations. However, the interaction of NAO and AMOC is very model dependent.

Here, we present the diversity across CMIP6 models in pre-industrial control experiments. The focus lies on simulations of the NAO, the AMOC, their interaction, and related variables on interannual to decadal timescales. Regarding the NAO-AMOC interaction, there are large differences in the strength of their relationship, in the location (like the latitude of the AMOC), its periodicity and in the time-lag between both variables.

Furthermore, we propose hypotheses of the causes for this diversity in the models. Specific processes involved in NAO-AMOC interaction might be of varying relative importance from model to model, for example, NAO-related buoyancy versus wind-forcing affecting the AMOC. Also, mean state difference like in the North Atlantic sea surface temperature might play an important role for causing differences in the variability across models.
Rates of erosion in the Japanese Alps during the Quaternary – Insights from trapped charge thermochronometry
Authors: Bartz Melanie , King Georgina E. , Anderson Leif S. , Herman Frédéric , Sueoka Shigeru , Tsukamoto Sumiko , Tagami Takahiro
Published: March 2022

The Japanese Alps uplifted throughout the Quaternary and reach elevations of up to 3,000 m today. However, understanding the interaction between rates of Earth surface processes, tectonics and climate is challenging, partly due to the difficulties of measuring changes in the rates of Earth surface processes at the timescale of glacial-interglacial cycles. In particular, the youth of the Japanese Alps has made measurement of their exhumation histories complicated. To help resolve this issue, we investigate the potential of ultra-low temperature thermochronometers based on the luminescence and electron spin resonance (ESR) of feldspar and quartz minerals, respectively. We focus on the Tateyama region in the Hida range, which was glaciated during the late Quaternary period. In total, eight samples were analyzed by luminescence and ESR thermochronometry. While most luminescence signals have already reached their upper dating limit, ESR signals do constrain exhumation rates.

We measured the ESR dose response and thermal decay properties of all samples, specifically targeting the Al and Ti centres. In general, thermal stability is higher for the Ti centre than the Al centre, resulting in ESR ages of between 0.5-0.9 Ma, although the natural intensity of the Ti centre is close to or above the upper dating limit. In contrast, the Al signal still grows with time and is suitable for determining finite exhumation rates. Initial inversions reveal rock cooling rates on the order of 80 °C/Ma, which can be inverted to preliminarily rates of rock exhumation of <3 mm/a within the past 1 Ma. In the next step, we will relate these rates to the climatic (glacial) and tectonic history of the Tateyama region.
Energy of the semidiurnal internal tide from Argo data compared with theory
Authors: Geoffroy Gaspard , Nycander Jonas , de Lavergne Casimir
Published: March 2022

A global map of the amplitude of the semidiurnal internal tide at the 1000 dbar level, obtained from Argo park-phase data, is converted to depth-integrated energy density. As opposed to current satellite altimeter data, the high sampling rate of the floats enables the direct observation of the total wave field, including waves with a time varying phase difference to the astronomical forcing. Thus, the Argo-derived energy content is only affected by mixing, scattering, and nonlinear processes. The Argo data alone do not allow for retrieving the distribution of the energy over the different vertical modes. Nevertheless, the modal partitioning of the Argo-derived energy content is inferred from other datasets. The results are compared with a geographical distribution of the internal tide energy content estimated with a Lagrangian ray tracing model. The outcome is in turn used to tune the modelled attenuation of low-mode internal tides.
Investigating the fluence of bright TGF events detected by the Atmosphere-Space Interactions Monitor
Authors: Sarria David , Østgaard Nikolai , Marisaldi Martino , Lindanger Anders , Mezentsev Andrey , Lehtinen Nikolai , Neubert Torsten , Christiansen Freddy , Reglero Victor
Published: March 2022

Terrestrial Gamma-ray Flashes (TGFs) are short flashes of high-energy photons produced by thunderstorms. They are intense phenomena that may have high photon fluxes with energies up to 40 MeV when observed from detectors in orbit. All instruments in space have suffered instrumental saturation during bright events, including CGRO-BATSE, RHESSI, Fermi-GBM, AGILE-MCAL and ASIM-MXGS. The effects include dead-time and pulse pile-up, which lead to an underestimation of the TGF fluences and, in some cases, incorrect photon energies. 
    A key asset of ASIM is that it has two detectors on the same platform: the High Energy Detector (HED, 300 keV to ~40 MeV) and the Low Energy Detector (LED, 50 keV to 400 keV). LED is only weakly affected, which makes it possible to estimate corrections to the HED measurements for even the brightest TGFs. With the method we propose, we estimate the loss of photons by combining the LED and HED measurements with GEANT4 Monte-Carlo simulations of the detector responses. 
    We applied the method to three TGF events. The first, TGF-200728, has about 0.15 counts per microsecond  per unit, and is not expected to experience saturation and is used as a sanity check for the method. The other events, TGF-181102 (1.5 counts per microsecond per unit) and TGF-181025 (2.8 counts per microsecond per unit), indicate that the HED misses at least 50% of the photon counts for the brightest TGF events.
S-wave velocity profile of an Antarctic ice stream firn layer with ambient seismic recording using Distributed Acoustic Sensing
Authors: Zhou Wen , Butcher Antony , Kendall J. Michael , Kufner Sofia-Katerina , Brisbourne Alex
Published: March 2022

Measurements of the seismic properties of Antarctic ice streams are critical for constraining glacier dynamics and future sea-level rise contributions. In 2020, passive seismic data were acquired at the Rutford Ice Stream, West Antarctica, with the aim of imaging the near-surface firn layer. A DAS (distributed acoustic sensing) interrogator and 1 km of optic fibre were supplemented by 3-component geophones. Taking advantage of transient seismic energy from a petrol generator and seismicity near the ice stream shear margin (10s of km away from the DAS array), which dominated the ambient seismic noise field,  we retrieve Rayleigh wave signals from 3 to 50 Hz. The extracted dispersion curve for a linear fibre array shows excellent agreement with an active seismic surface wave survey (Multichannel Analysis of Surface Waves) but with lower frequency content. We invert the dispersion curves for a 1D S-wave velocity profile through the firn layer, which shows good agreement with the previously acquired seismic refraction survey. Using a triangular-array geometry we repeat the procedure and find no evidence of seismic anisotropy at our study site. Our study presents challenges and solutions for processing noisy but densely sampled DAS data, for noise interferometry and imaging. 
Analysis of volcanic activity of Yasur volcano with long range infrasound observation
Authors: Morelli Rebecca Sveva , Campus Paola , Coppola Diego , Marchetti Emanuele
Published: March 2022

The atmospheric injection of gas and material produced by an explosive volcanic eruption determines a rapid compression of the atmosphere, which subsequently propagates as longitudinal elastic waves (sound). The size of the source, generally greater than tens of meters, and its duration, longer than few seconds, result into an emitted signal that is particularly rich in low frequency (f < 20 Hz), thus determining an efficient infrasound radiation. Thanks to the low spectral content and the reduced attenuation in the atmosphere, infrasound is capable of propagating for very large distances.

In this study we show how the infrasonic monitoring of volcanoes at regional distances (> 100 km) is efficient in recording and characterizing volcanic events. For the purpose of our study, detections from the Yasur volcano (Tanna Island, Vanuatu) registered at a source-to-receiver distance of 400 km by the IS22 infrasound array, located in New Caledonia and part of the Comprehensive nuclear Test Ban Treaty (CTBT) International Monitoring System (IMS), were studied for a period of eleven years (2008-2018). The predominantly explosive Strombolian activity of this volcano makes it a perfect subject to be studied by infrasound technology.

Detections of infrasound signals from Yasur volcano, that are modulated according to the seasonal variation of stratospheric winds, are corrected for attenuation accounting for real atmospheric specification between the source and the receiver to retrieve the pressure at the source: next, they are used to evaluate long term (yearly) and short term (hourly) variations of activity over the period of analysis. Results are eventually compared with thermal anomalies recorded by the MODIS (MODerate resolution Imaging Spectroradiometer) installed on NASA's Terra and Aqua satellites and computed by the MIROVA hotspot detection system.

We show that even at regional (400 km) distances it is possible to follow the fluctuations of ordinary explosive activity during periods of optimal propagation of infrasonic waves in the atmosphere, In addition, we show that, when the signal is recorded, the time resolution retrieved from the analysis allows following variations of activity at hourly time scale, thus representing a valuable source of information, in particular in areas where local geophysical observation is missing.
Overestimation of elevation-melt feedback in uncoupled projections of ice sheet mass loss
Authors: Vizcaino Miren , Mikolajewicz Uwe , Sellevold Raymond
Published: March 2022

The elevation feedback on melt has been identified as a key process to explain (Gregoire et al, Nature, 2012) and project (Aschwanden et al., Sci Advances, 2019; Ridley et al, J Clim, 2005; Vizcaino et al, Clim Dyn, 2008) long-term deglaciation. It is also central to the theory of ice sheet evolution hysteresis, deglaciation thresholds/tipping points, and the problem of reversibility (Garbe et al, Nature, 2020; Gregory et al, TC, 2020; Gregory et al, Nature, 2004, Robinson et al, Nature Clim. Change, 2012). Ice-sheet-model-only estimates of this feedback rely on a largely unexplored parameter, the so-called “lapse rate”. This parameter is defined as the rate at which the near-surface atmospheric temperature changes strictly due to surface elevation change.

In this work, we use coupled an uncoupled ice sheet and climate simulations with two different General Circulation/Earth System Models (Vizcaino et al, GRL, 2015; Muntjewerf et al, JAMES, 2019) to estimate the temperature lapse rate over the Greenland ice sheet as it deglaciates. We find that this lapse rate is highly variable over seasons, with much reduced lapse rates during summer over melting surfaces. We propose that uncoupled  state-of-the-art projections are likely overestimating deglaciation rates due to too high summer lapse rates over the ablation area.
River water input from upstream areas into the Cuvette Centrale peatland complex detected via SMOS data assimilation
Authors: Apers Sebastian , De Lannoy Gabriëlle , Cobb Alexander R. , Dargie Greta C. , Reichle Rolf H. , Bechtold Michel
Published: March 2022

The 16.5 million ha Cuvette Centrale peatland complex in the Congo Basin was described for the first time in 2017. However, a proper understanding of the entire hydrological functioning of this peatland complex is a challenge and large-scale land surface models (LSMs) are unlikely to accurately represent the circulation of water in this area. One of the major issues of large-scale LSMs is the quantification of the spatially- and temporally-variable lateral water input from rivers into peatlands.

In this research, we applied our recently developed tropical peatland-specific module PEATCLSMTrop,Nat in a land surface modeling and assimilation scheme that uses L-band brightness temperature (Tb) data from the Soil Moisture and Ocean Salinity (SMOS) satellite mission. Despite the dense vegetation cover in tropical peatlands, preliminary results showed that the data assimilation improved the water level estimates at 4 evaluation sites over model-only simulations, with mean correlation coefficients of 0.46 for the model-only and 0.63 for the data assimilation estimates, and mean anomaly correlation coefficients of 0.02 for the model-only and 0.26 for the data assimilation estimates. To gain insight into the large-scale hydrology of the Cuvette Centrale peatland complex, we analyzed data assimilation diagnostics and found temporally autocorrelated positive and negative total water storage (tws) increments (=tws correction introduced via data assimilation) over periods of up to four months over the Cuvette Centrale peatlands. This is indicative of a temporarily suboptimal assimilation system, due to a shortcoming in the LSM. Since PEATCLSMTrop,Nat does not simulate lateral water input and the positive autocorrelated periods of tws increments coincide with anomalies in river stages measured upstream, it suggests that lateral water input (=flooding) from upstream mineral areas into the peatlands of the Cuvette Centrale is an important but unmodelled process in its hydrology. This means that land use change and a climate change-induced precipitation reduction in upstream mineral areas will influence the local hydrology of the Cuvette Centrale peatland complex, making it even more vulnerable to external disturbances.
Thermo-kinematic evolution of the Eastern Alps along TRANSALP: Exploring the transient tectonic state towards slab reversal
Authors: Eizenhöfer Paul , Glotzbach Christoph , Kley Jonas , Ehlers Todd
Published: March 2022

The Eastern Alps are shaped by the indentation of Adria into Europe and exhibit a doubly-vergent lithospheric wedge geometry. Immediately after the subduction of the Penninic ocean, pro- and retro-wedges have been established in the European and Adriatic plates, respectively. Recent tomographic studies, depicting several detached slab fragments beneath the Alps, have been interpreted as evidence of continuous southward subduction, contrary to an often-invoked subduction polarity reversal. Systematic changes in orogen-scale exhumation, driven by rock displacement along active faults, should reflect such change in subduction polarity. Low temperature thermochronology can evaluate upper lithospheric cooling as a response to changes in tectonic and/or erosional boundary conditions. This study investigates whether a potential change in locations of the pro- and retro-wedges is reconcilable with observed crustal re-organisations, exhumation patterns and mantle tomography. A suite of thermo-kinematic forward models driven by a new 2D structural-kinematic reconstruction of continental collision along the TRANSALP profile in the Eastern Alps has been subject to systematic sensitivity analyses encompassing variations in shortening rates, thermophysical parameters and topographic evolution, supplemented by new apatite and zircon fission-track data. Results from the thermo-kinematic modelling reproduce: (i) the orogen-scale structural geometry, (ii) the distribution of low-temperature thermochronometer ages, (iii) independently determined time-temperature paths, and (vi) the present-day surface heat flux. We suggest that the observed thermochronologic record along the TRANSALP profile is primarily driven by cooling through rock displacement along active faults. Our thermo-kinematic reconstruction emphasises a systematic southward shift of deformation, in particular in the Southern Alps, since onset of motion along the Tauern Ramp. Interpreting both, the Tauern Ramp as a mega retro-thrust and the southward shift of deformation in the Southern Alps, as a response to new Coulomb-wedge criterions, then our results are consistent with a Mid-Miocene reversal of continental subduction polarity. This time frame is compatible with a detachment of the European slab and a tectonic re-organisation of the Eastern Alps since ~10-25 Ma.   
Results by the Open-Air Laboratory Italy 
Authors: Ruggieri Paolo ,   The OAL-Italy
Published: March 2022

The Open-Air Laboratory, a novel concept developed by the EU-funded Operandum project(OPEn-air laboRAtories for Nature baseD solutions to Manage Environmental risk) to co-design,implement and assess the effectiveness of Nature-Based Solutions (NBSs), has been introduced at the EGU General Assembly 2021  (Ruggieri, P. and the OAL-Italy: The Open-Air Laboratory Italy, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9495, https://doi.org/10.5194/egusphere-egu21-9495, 2021.). In this work we present the results obtained in the framework of the Open-Air Laboratory Italy (OAL-Italy) related to innovative NBSs to mitigate the impact of hydrometeorological hazards in present and future climate. The results are multidisciplinary and involve novel modelling strategies, laboratory measurements and targeted monitoring open-field campaigns in three operational sites, where NBSs are implemented to mitigate a range of hydrometeorological hazards such as coastal erosion, flooding, storm surge and salt wedge intrusion. Innovative NBSs tested and developed by the OAL include deep-rooted plants installed on a river embankment to prevent levee failures, special plants that can live in high salt concentration and remove salt from the river mouth water, an artificial dune and marine seagrass to mitigate the impact of storm surges and coastal erosion. The three sites where these NBS are implemented are located in the Emilia Romagna region, in Northern Italy and they involve the Panaro river, a tributary of the Po river, a branch in the Po river delta and a beach in the north Adriatic sea close to the delta Po river. The innovative approaches to tackle the mentioned hazards are described and results in terms of monitoring campaign results in combination with modelling results are presented. We discuss the innovative approach proposed to test and validate the efficacy of the NBS in present and future climate, in order to evaluate the replicability and the upscaling of the NBSs. We confirm that the OAL constitutes an unprecedented holistic effort towards sustainable land management, adaptation to climate change and the acceptance of Nature-Based Solutions.
Improving NWP forecasts through the direct 4D-Var assimilation of space-borne cloud radar and lidar observations
Authors: Fielding Mark , Janisková Marta
Published: March 2022

As the fidelity of global numerical weather prediction (NWP) models to resolve convective scale features increases with advances in computing power, high-resolution observations of clouds and precipitation are becoming increasingly important for both evaluating model performance and initialising forecasts. This talk focusses on the latter by presenting developments made to the ECMWF integrated forecast system (IFS) to allow the direct 4D-Var assimilation of spaceborne cloud radar and lidar observations. Due to the radar and lidar signal’s ability to penetrate clouds, these observations provide a unique insight to the vertical and horizontal structure of clouds. The additional information provides a fantastic opportunity to improve the model analysis of cloud and precipitation and the subsequent forecast, however extracting useful information from these observations, which are often only partially resolved by the model, pushes current data assimilation systems to their limit.

In this talk we will provide an overview of the developments to the IFS to allow the assimilation of cloud radar and lidar, including a triple-column technique to represent unresolved condensate variability in the simulated observations and the characterisation of observation error, both of which are vital to optimise the observations’ use. We will then give a thorough assessment of the impact of assimilating cloud radar and lidar on NWP forecast skill by assimilating CloudSat radar reflectivity and CALIPSO lidar backscatter on top of routinely assimilated observations. As well as showing improvements by evaluating forecasts against analyses, we will show the observations provide increases in forecast skill when verifying against independent observations, such as top-of-atmosphere radiative fluxes. Looking to the future, the upcoming ESA EarthCARE satellite mission will provide the opportunity to assimilate cloud radar and lidar observations operationally. Differences between CloudSat and CALIPSO with EarthCARE observations will be briefly discussed along with the potential for synergistic uses of other EarthCARE observations, such as Doppler velocity, cloud extinction and shortwave radiances.
Model error covariance estimation in observation space weak-constraint 4DVar
Authors: Pein Anne , Van Leeuwen Peter Jan
Published: March 2022

Weak-constraint 4DVar (WC-4DVar) not only takes errors in initial conditions into account but also assumes that the physical model itself is erroneous. As model errors, arising e.g. from unresolved processes, can be substantial in geoscience applications, the weak-constraint formulation yields more accurate results compared to its strong-constraint counterpart. Furthermore, accuracy in forecasting should be improved since the algorithm produces an optimal solution at the end of the assimilation window, instead of revised initial conditions. Finally, WC-4DVar allows for longer assimilation windows because of reduced sensitivity to initial conditions. 

 

However, for complex high-dimensional models, it is not simple to estimate the model error covariances, as needed in the WC-4DVar algorithm. A promising approach to address this challenge might look as follows: We start with a first-guess model error covariance, e.g. a scaled-down (in amplitude and length-scale) initial state (background) covariance (the so-called B-matrix) with added time correlation, and perform a WC-4DVar assimilation step. This yields, besides an optimised solution at the end of the assimilation window, estimates for the model errors. We then use these model errors to derive new model error covariances with which we perform the next assimilation step. This procedure is iterated.

 

In this talk, we present initial results of this approach applied to the Burgers’ equation and using an observation-space WC-4DVar algorithm (sometimes called PSAS). We outline the procedure, demonstrate its feasibility, and discuss extensions to real-world systems.
A revision of the main active fault systems of the Alboran Basin: their significance in plate tectonics and a first appraisal of its seismogenic and tsunamigenic potential.
Authors: Gómez de la Peña Laura , R. Ranero César , Booth-Rea Guillermo , Azañón José Miguel , Gràcia Eulàlia , Maesano Francesco , Basili Roberto , Romano Fabrizio
Published: March 2022

The Alboran Basin is located in the westernmost Mediterranean Sea. This basin was formed during the Miocene, and since the late Miocene, has been deformed due to the Iberia – Africa tectonic plates convergence, producing the contractive reorganization of some structures at the basin. Thus, the Alboran Basin is a seismically active area, which hosts the plate boundary between the European and African tectonic plates. This plate boundary has been traditionally considered a wide deformation zone, in which several small faults are accommodating the deformation.

Based on a modern set of active seismic data, we were able for the first time to quantify the total slip accommodated by the most prominent tectonic structures of the area, late Miocene - early Pliocene in age. Our results show that the estimated total slip accommodated by the main fault systems may be similar (with error bounds) to the estimated plate convergence value since the Messinian time (~24 km). Thus, slip on that faults may have accommodated most of the Iberian – African plate convergence during the Plio-Quaternary, revealing that the contractive reorganization of the Alboran basin is focused on a few first-order structures that act as lithospheric boundaries, rather than widespread and diffuse along the entire basin.

These results have implications not only for kinematic and geodynamic models, but also for seismic and tsunami hazard assessments. Using the most complete dataset until the date, we performed a revision of the geometry and characteristics of the main fault systems offshore. Based on this data, we perform a first appraisal of the seismogenic and tsunamigenic potential of the main fault systems offshore. Our simulations show that the seismogenic and tsunamigenic potential of the offshore structures of the Alboran Basin may be underestimated, and a further characterization of their associated hazard is needed.
Air-borne glyoxal measurements in the marine and continental atmosphere – comparison to TROPOMI satellite data and EMAC model simulations
Authors: Kluge Flora , Lerot Christophe , Rosanka Simon , Rotermund Meike , Taraborrelli Domenico , Weyland Ben , Pfeilsticker Klaus
Published: March 2022

This study presents glyoxal observations of the mini-DOAS instrument performed during seven different airborne campaigns (ACRIDICON-CHUVA (2014), OMO (2015), EMeRGe-EU (2017), EMeRGe-Asia (2018), CoMet (2018), CAFE (2018), and SouthTRAC (2019)) from the German HALO (High Altitude and LOng range) research aircraft. Geographic regions covered by the research missions include the southern tip of South America, the Weddell sea and the Western Antarctic Peninsula, the tropical and subtropical Atlantic, Europe, as well as the East China Sea, the Philippines, and Japan. The studied areas thus covered observations over (i) natural source regions of glyoxal and its precursors, (ii) local as well as regional pollution sources i.e. biomass burning and major anthropogenic activities, and (iii) the remote marine and terrestrial background atmosphere. Using simultaneous measurements of horizontally (Limb) and vertically (Nadir) aligned telescopes, atmospheric concentrations and vertical column densities (VCDs) of glyoxal along the flight tracks are inferred. For validation purposes, these air-borne measurements are compared to collocated observations of the TROPOspheric Monitoring Instrument (TROPOMI). Overall, a reasonable agreement among the two data sets is found. Finally, both measurements are compared to simulations of the global ECHAM/MESSy Atmospheric Chemistry (EMAC) model (*), which provide further insights into the different sources and sinks of glyoxal and its precursors as well as into its photochemistry.

(*) See also the presentation of Rosanka et al., entitled ‘Improving the representation of glyoxal in the global EMAC model using TROPOMI retrievals and air-borne campaign data’.
Seismological and petrophysical properties of the lithospheric mantle in a nascent rift
Authors: Clutier Adeline , Gautier Stéphanie , Parat Fleurice , Tiberi Christel
Published: March 2022

The North Tanzanian Divergence (NTD) is a rift initiation zone situated at the southern tip of the Eastern Branch of the East African Rift. This zone is a unique continental open-air laboratory to study the beginning of the continental break-up. The rift surface expression results from the interaction between tectonic and magmatic processes. However, the role of each process on the observed surface activity is still debated, as their respective signal is difficult to differentiate. In order to consider the various factors that may interact in this complex zone, a multi-disciplinary study was carried out, combining seismological and petrophysical approaches.

First, our recent development of a new hybrid tomographic method for both P and S-body waves permitted to image at depth the main suture zones between the inherited structures (Archean craton and Proterozoic orogenic belts) and the mantle plume extension (Clutier et al. 2021). We also inferred zones of fluid (melt or gas) presence from the Vp/Vs ratio maps deduced from these P and S independent inversions. Then, to quantify the proportion of fluid from the tomographic images, we carried out a petrophysical study on mantle xenoliths from the Pello Hills volcano, situated in the rift axis. The clinopyroxene-amphibole-phlogopite vein-bearing xenoliths allowed to compute, at a sample scale, the seismic properties of the mantle with and without crystallised or fluid-filled veins. By varying the composition and increasing the proportion veins in the samples, the P and S-wave maximum velocities can decrease from 9.2 down to 5.3 km/s and from 5.1 down to 3.1 km/s, respectively. Those velocity models point out anisotropy in the mantle below the NTD, and particularly in highly metasomatized zones. Finally, despite the difference in spatial and temporal scales between the petrological and geophysical studies, we managed to combine the tomographic velocity anomalies and the xenolith’s seismic properties to infer a maximum volume of fluid in the lithospheric mantle below Pello Hills volcano. This volume may be intermediate between 20% of clinopyroxene-phlogopite-amphibole crystallised vein and 10% melt/fluid-filled vein.
Mechanisms of centennial AMOC variability in a climate model of intermediate complexity
Authors: Mehling Oliver , Angeloni Michela , Bellomo Katinka , von Hardenberg Jost
Published: March 2022

Centennial-scale climate variability in the North Atlantic is characterized by the absence of a clear external forcing. Hence, identifying mechanisms of internal variability at these timescales is crucial to understand low-frequency climate variations. For this task, long control simulations with coupled climate models represent a key tool.

Although significant spectral peaks in centennial variability in the Atlantic Meridional Overturning Circulation (AMOC) were found among some state-of-the-art models, CMIP6 models disagree on the amplitude, periodicity and even existence of centennial AMOC variability. This disagreement motivates the use of models of reduced complexity with idealized setups and perturbed physics ensembles to elucidate the mechanisms of AMOC variability at long timescales.

Here, we investigate multi-millennial piControl simulations of PlaSim-LSG, an earth system model intermediate complexity (EMIC). For a range of vertical oceanic diffusion parameters, PlaSim-LSG exhibits strong oscillations of AMOC strength, as well as of salinity and surface temperatures in the North Atlantic, with a period of about 270 years.

Lag correlation analysis shows that a positive feedback involving the interplay of surface salinity, freshwater flux and sea ice concentration in the Norwegian Sea and the Arctic Ocean is the key driver behind these oscillations. In contrast to previous studies with other models, interhemispheric coupling only plays a minor role. We discuss preliminary results of sensitivity experiments for testing the proposed mechanism, and compare our results with previously proposed mechanisms of AMOC oscillations in CMIP6 models.
Parameterising CO2 air-sea gas transfer with wave breaking energy dissipation rate, sea state, and wind speed
Authors: Smith Andrew , Callaghan Adrian , Bidlot Jean-Raymond
Published: March 2022

Air-sea gas exchange has up-scale ramifications for global climate and ocean biogeochemistry that are of paramount relevance. Gas transfer velocity (k) measurements or appropriate parameterizations for them are required to quantify the fluxes and budgets of the important trace gases (e.g., CO2, DMS, and CH4). Where gas flux and concentration gradients are not explicitly measured, k is subdivided into diffusive and bubble-mediated components – each parameterized. Although diffusive transfer velocity, ks , has been well-described by power-law relationships involving the Schmidt number Sc, large variability exists in parameterizations for bubble-mediated gas transfer velocity, kb. Since kb is driven primarily by entrainment of gases through wave breaking, the uncertainty is acutely problematic at high winds where gas flux measurements are scarce. To address the paucity of such data, the High Wind Gas Exchange Study (HiWinGS) directly calculated gas transfer velocity of CO2 (kCO2) from flux and concentration gradient measurements taken in the Labrador Sea from October 9 – November 13, 2013, where 10-meter neutral wind speeds ranged between 1.8 – 25.2 m s-1. We use these data to validate a novel gas transfer velocity parameterization constructed using output from a wave hindcast obtained with the spectral wave model (ecWAM) forced with the European Centre for Medium-Range Weather Forecasts (ECMWF) 5th Generation Reanalysis (ERA5). Our parameterisation combines a diffusive term based on wind speed and Sc, and a bubble-mediated term based on gas solubility, wave age, and wave breaking energy dissipation rate to capture gas transfer velocity. We compare our results to common wind-speed-only parameterisations and more recent sea-state based relationships.
Diels-Alder-Reactions in nanometer aerosol particles
Authors: Klink Daniela , Hoffmann Thorsten
Published: March 2022

To predict the composition of the atmosphere in the context of understanding global climate change, knowledge about the formation of new aerosol particles and their growth is increasingly important. Nanometer-sized aerosol particles are initially formed by nucleation and then grow under the influence of organic molecules. Especially the small particle embryos form a unique chemical environment at the nanoscale, as they could influence chemical reactions due to their size-dependent physical properties. For example, smaller particles have higher internal pressure (Laplace pressure), which could influence reaction rates and equilibrium status in pressure-dependent reactions. In general, bond-forming chemical reactions should be favored at higher pressure, so they gain importance in small particles. Therefore, particle size-dependent chemical reactions could play a crucial role in the life cycle of atmospheric aerosols. Here we present results on Diels-Alder reactions with suitable dienes and dienophiles in nano-aerosol particles, which represent a pressure-sensitive chemical system. N-methylmaleimide as a dienophile in the particle phase and cyclopentadiene as a diene in the gas phase were chosen for their reactivity, volatility, and detectability. We study the growth and behavior of the aerosol particles and the product formation. The analysis is performed with Scanning Mobility Particle Sizer Systems (SMPS) and a GC-MS system with thermal desorption.
Constraining river streamflow determination using bathymetry and slope from ICESat-2 satellite altimetry
Authors: Sneeuw Nico , Wang Bo , Bao Jingyi , Ke Siqi , Tourian Mohammad
Published: March 2022

In order to determine river streamflow over poorly gauged basins, spaceborne techniques are widely used to obtain hydraulic parameters like river height variation (H), slope (S), river width (W), velocity (V) and river cross section (or bathymetry). Conventional radar altimetry can only provide water height. It is also difficult to measure the slope of a reach even from multi-mission altimetry, due to the problems of the simultaneity and intersatellite biases.

Laser altimetry with ICESat-2 enhances the opportunity to constrain river streamflow. The Advanced Topographic Laser Altimeter System (ATLAS) on the mission carries 3 pairs of laser transmitters (one strong and one weak beam in each pair) with photon-counting detectors. ATLAS emits 532-nm laser pulses (green light) at a 10 kHz repetition rate. It detects individual photons at 70 cm along-track separation for each shot on the earth’s surface with ~17 m diameter footprint. The very dense measurements can provide the height profile of the cross section. Since the laser penetrates water, it can potentially measure the river bathymetry, at least the nearshore part, depending on the turbidity of the water. With its off-nadir beams, the system is able to provide the slope of a reach.

In our study, we process the point cloud of the river cross section and extract the nearshore river bathymetry. The slope is determined by three strong beams of one track. We also analyze the maximum depth of bathymetry in different seasons and different turbidity conditions. The water height of each beam is obtained from measurement of the center of the river (centerline from SWOT River Database), and validated with measurements of the weak beams.