In the northeastern Atlantic Ocean, the eastward-flowing Azores Current converges towards the southwestward-flowing Canary Current, following the African coastline and leading the Eastern Boundary Current System of the North Atlantic Subtropical Gyre. Based on satellite altimetry measurements (1992-2006) and in situ observations (1998, 2002), Sangrà et al. (2009) described for the first time the Canary Eddy Corridor in the northeastern Atlantic Ocean (22.1oN - 29.1oN) as a zonal long-lived mesoscale eddy corridor. In this work, we extend the study area and redefine five zonal corridors that expand from 12oN to 40oN. The aim is to assess the potential role of these eddy corridors as zonal conveyors of mass and ocean properties. To ease its identification, we name these corridors following their generation sites: Cape Verde, Cape Blanc, Canary Islands, Madeira, and the Azores Front. We do this using an altimeter-based dataset of global mesoscale ocean eddies (1992-2018). The analyses are performed in terms of the eddy demography and eddy geometric properties. Generally, we find that cyclonic eddies (CEs) are the most frequent type of long-lived eddies (> 6 months) everywhere but in the Cape Verde Corridor and the Azores Front Corridor, where anticyclonic eddies (AEs) and CEs are of similar number. On average, CEs propagate the farthest away due to the combination of longer lifetimes and higher track stabilities, although AEs also reach on occasions as far as 1000 km away from their generation site. Zonally, results agree well with theory and show recurrent patterns about their geometric eddy properties, where both anticyclonic (AEs) and cyclonic (CEs) eddies display significant differences. Both eddy types increase (decrease) its radius and decrease (increase) its amplitude and rotational speeds when their corridor locates at lower (higher) latitudes. Also, observed eddies propagate west at approximately the phase speed of nondispersive baroclinic Rossby waves, according to their latitude. These results highlight the implications of the geographical location (latitude) of the eddy corridors, suggesting that low latitude eddy corridors may generate the best candidates to convey ocean properties to remote places while these candidates are significantly less frequent than eddies of higher latitude corridors.

As noted in the session description any research object produced should be made ’FAIR’; but ‘FAIR’ objects require attribution. What does that mean for the vast variety of research objects? What roles need to be acknowledged, how and where? These are questions the Federation of Earth Science Data Partners (ESIP) Research Object Citation cluster have been addressing. In particular, we have been applying the lens of the CREDiT taxonomy roles in these discussions. Here our conclusions to date will be described.

The Salton basin is an arid, sub-sea level basin located in southeastern California. Mountain ranges border the basin directly to the west and east, to the north extends a narrow valley that terminates with a transverse mountain range, and to the south spans heavily irrigated, agricultural lands that gradually rise in surface elevation. Within the basin lies the Salton Sea, and surrounding the Sea is diverse terrain that includes dry playa, rocky and vegetated surfaces, and highly emissive alluvial fans and dry washes, among others. Although large dust outbreaks due to orographically forced high wind speed events are frequent in the area, measurements from a new AERONET site stationed within the basin shows that dust is a standard component of the region's atmosphere, even on days with otherwise low wind speeds. We find a diurnal cycle of background dustiness that peaks in the early afternoon. An analysis of boundary layer structure using a Vaisala CL51 suggests that deepening of the boundary layer due to dry convection results in downward mixing of momentum, increased surface wind speeds, and an accumulation of dust in the mixed layer. Further analysis of the CL51 observations at nighttime suggest that high AOD concentrations persist in the shallow nocturnal boundary layer, and can become elevated throughout the night due to westerly katabatic flows. An analysis of surface meteorological station data suggests possible pathways of suspended dust due to mountain and valley flows within the basin.

Interannual changes in spectral irradiance at UV wavelengths is one of sources of solar-driven decadal variability in the atmosphere and in particular in the stratosphere as most of these changes happen at UV wavelengths. In last recent years, it has been suggested that energetic electron precipitation (EEP) also contributes not only to alter the chemical composition of the middle atmosphere but also its dynamical variability through changes in stratospheric ozone. In this study we investigate the effects of the two forcings and their interactions. We employ 35-year long integrations of the atmospheric version of the Whole Atmosphere Community Climate Model version 5 with different idealized and stationary solar and geomagnetic forcing terms. Four experiments are carried out combining high (H) and low (L) solar radiative forcing and high (7) and low (3) EEP associated with geomagnetic activity: H7 (with high radiative forcing and high EEP), H3 (high/low), L7 (low/high), and L3 (low/low). We find that the extension, the seasonality, and the significance of the effects of these two forcing terms on the atmospheric variables like temperature, NOx, and ozone are dependent on the joint effects of both forcing terms. The effect of the impact on NOx, ozone and temperature was measured, on constant pressure levels, by means of a Monte Carlo test. Under minimum solar conditions EEP affects mainly the NOx field on constant pressure levels, even though vertical cross sections show statistically significant effects on temperature and ozone in the southern hemisphere during austral winter and the following spring. Under solar maximum condition the effect of EEP becomes important. Ozone depletion (augmentation) in the upper levels of the stratosphere due to more (less) NOx, produced by EEP, allows UV radiation to produce more (less) ozone in the lower levels of the stratosphere. Solar irradiance hence plays an important role in modulating the impact of geomagnetic activity on climate variables.

Combining auxiliary variables and ground data of forest parameters using the model-based approach has become a frequently used methodology to produce synthetic estimates for small areas. These small areas arise as it may not be financially feasible to take ground measurements or some areas may be inaccessible to ground-based personnel. Until recently, these estimates have been calculated without providing a measure of the variance or in large homogeneous forested areas where the variability would be minimal. This paper uses a Random Forest algorithm to produce estimates of QMDBH (cm) and volume (m3 ha-1) and a k-nn technique to produce variance estimates in a previously unproven heterogeneous forest environment. The area of interest (AOI) was the commercial forest in the Slieve Bloom Mountains in the Republic of Ireland, where the majority species are Sitka spruce (Picea sitchensis (Bong.) Carr.) and Lodgepole pine (Pinus contorta Dougl.). Field plots were measured during the Summer in 2018 during which a LiDAR campaign was flown and Sentinel 2 satellite imagery captured, which were both used as auxiliary variables. Root mean squared errors (rmse) for the modeled estimates of QMDBH and volume were 4.4 cm and 111 m3 ha-1 and the r2 values were 0.65 and 0.76 respectively. An independent dataset of pre-harvest forest stands was used to validate the modeled variance estimates. The results showed that 73% of QMDBH measurements and 60% of volume measurements were within the confidence intervals of the estimated values. The mean percentage standard deviation for QMDBH and volume were 17% and 21% respectively. This application of variance estimation in such a heterogeneous forest landscape adds further weight to the applicability of the methodology in a range of forest landscapes. This finding is extremely important as it highlights the benefits of using earth observation data to produce estimates and confidence intervals for small areas in heterogeneous forest landscape.

Mount St. Helens, Washington State, USA, is characterized by a 2 x 3.5 km horseshoe-shaped and north-facing crater and hosts one of the last expanding glaciers in the Cascade Volcanic Arc, Crater Glacier. First observed in 2012, a new and extensive system of glaciovolcanic caves has developed around the 2004-2008 Lava Dome inside the Crater Glacier. Field studies have documented the cave characteristics via photography and tacheometric survey methods repeated from 2014-2019. Climatologic measurements reveal that sub-glacial fumarole activity leads to large-scale cave complexes, sometimes several hundred meters long. These allowed comparisons of passage extent and volume to be made and gave us a unique opportunity to observe their genesis over time. Ten distinct caves have been discovered in a circumferential pattern surrounding the 2004-2008 Lava Dome. The caves comprise a combined length of 2,232.3 m, the three most significant ones reaching more than 400 m each. Changes in the output of individual fumaroles which have melted the passages have also contributed to the appearance and disappearance of subglacial rooms and marginal dendritic passages which typically orient to entrances along the rock/ice interface. Over time the caves have demonstrated significant morphological changes. Multiple caves demonstrated increases in length and volume over the study period, along with changes to internal morphology. Caves located on the east and west arm of the glacier are additionally influenced by glacier movement and a fast flow rate which contribute much to morphology changes. Resurveys of cave passages over multiple years have revealed the dynamic nature of the systems, which are not necessarily in balance with the geothermal heat release. We expect that the overall growth of the cave systems will continue as long as an equilibrium of snow accumulation and ablation is reached or changes in volcanic activity occur. The newly formed glaciovolcanic cave systems on Mount St. Helens offer a rare view into the internal workings of a glacier and can lead to a better understanding of how glaciers and active volcanoes interact.

Fault zone usually presents a granular gouge, coming from the wear material of previous slips. Considering a mature fault gouge with mineral cementation between particles, we aim to understand the influence of these cohesive links on slip mechanisms. As cohesion is difficult to follow and to quantify with Lab or in-situ experiments, we choose to use Discrete Element Method that has already shown its ability to represent granular gouges with relevant kinematics and rheology. In this work, we consider a dry cohesive contact model in 2D (2x20mm²) involving two rough surfaces representing the rock walls separated by the granular gouge (5000 particles, grain size 27- 260 μm). A step forward compared to literature is to add cohesion on real angular and faceted grains that modifies contact between particles. Focusing on physics of contacts inside the granular gouge, we explore contact interactions and friction coefficient between the different bodies. To represent the cementation we set up a Bonded Mohr-Coulomb law, considering that inter-particular bridges and particles are made with the same material. This numerical model is displacement-driven and is implemented to study the peak of static friction (shape, slope, duration) under a confined pressure of 40 MPa. Depending on the compacity and on the cohesion level of each model, the peak strength may be sharp, short, and intense for dense and highly cohesive cases or smooth, delayed with moderate amplitude for mid-dense and moderately cohesive cases. Three main behaviors are observed: a non-cohesive regime where the added cohesion is too small to truly disturb the global slip mechanism (Couette flow), an intermediate cohesive regime with clusters of cohesive grains, changing the granular flow and acting on slip weakening mechanisms (Riedel shear band R1) and an ultra-cohesive regime where gouge behaves as a brittle material with several Riedel shear bands emergence. We also investigate the role of cohesive bonds in energy budget, focusing on fracture energy term. Three mechanisms are playing a role in fracture energy evolution: the rupture of cohesive bonds, the dilatancy of the gouge and Coulomb dissipations due to friction. These factors are linked to the initial percentage of cohesion inside the sample and help characterize the mechanisms at stake in the initiation of sliding.

The solar polar fields play a crucial role in sustaining the solar dynamo mechanism. Observations and computational modelling indicates that the surface dynamics of active regions mediated via plasma flows, which leads to the polar field build-up, is a fundamental aspect of the solar dynamo mechanism; in fact, this surface mediated flux dynamics also known as the Babcock-Leighton mechanism, is now implicated to be the leading contributor to the Sun’s polar field, and thus also provides a window to the future solar cycle. This emergent understanding is one of the major drivers of novel mission concepts aiming to image the solar high latitudes from out of the ecliptic locations. Based on numerical simulations of the near-surface magnetic field dynamics and the Sun’s polar landscape, here we discuss what new insights may be provided by out-of-the ecliptic solar physics missions.

A substantial amount of dust aerosol was transported to the central Himalayas during the multiple dust storm event that occurred from 12 to 15 June 2018 in the Thar desert, northwestern India. In this study, we implemented a cloud-resolving Weather Research and Forecasting model coupled with chemistry (WRF-Chem) to assess the impact of transported Thar-related dust aerosols on precipitation processes over the central Himalayas. We isolated the effect of the transported dust on the precipitation distribution by zeroing out dust aerosols from lateral boundary condition and keeping other species of aerosols. Results show the noticeable impacts of transported dust aerosols on regional precipitation and cloud properties over the central Himalayas. When transported dust is included, spatially averaged (25°N-31°N and 78°E-89°E) AOD increases by 0.36. Over the Himalayas foothills with the dust, precipitation is enhanced by 7.5% (0.63mm), while surface temperature is reduced. The presence of mineral dust aerosols increased the cloud droplets and ice crystal number concentration, which is further facilitated by the mountainous terrain by orographic lifting, leading to enhanced precipitation. We diagnosed the role of cloud microphysics and that of the cloud dynamics in the simulated precipitation sensitivity. This study highlights the effect of remote dust aerosol on the perturbation of cloud microphysical properties, which can significantly influence precipitation over the Himalayas and impact the regional hydrology.

Landcover information is of relevance for a range of applications in Arctic environments including up-scaling of in situ measurements, permafrost monitoring and modelling and climate change impact assessment. But not only natural landcover types, also the identification of human impacted areas is required. A wide range of satellite records are available, but often there are coverage and resolution limitations. Due to the spatial heterogeneity typical for the Arctic, an as high as possible spatial resolution is needed. Sentinel-1 as well as Sentinel-2 offer 10m nominal resolution for specific bands and modes and are freely available across the entire Arctic. The multi-spectral information from Sentinel-2 is specifically of value for discrimination of tundra types. The Synthetic Aperture Radar mission Sentinel-1 provides added value through representation of land surface structure features. A combination of both allows significantly improved characterization of landcover over larger areas. Here, we review recent progress in monitoring the land surface close to Arctic coasts (focus region of HORIZON2020 Nunataryuk), specifically the distribution of human impacted areas beyond of what is represented in databases such as OpenStreetMap or global settlement maps. The added value of machine learning techniques will be discussed and results based on Sentinel-1 und Sentinel-2 presented. Further on, permafrost change information provided through the ESA CCI+ Permafrost project is combined with the novel maps. The CCI+ Permafrost datasets cover 1997-2018 for ground temperature, active layer thickness and permafrost fraction with 1 km gridding (partially derived from MODIS LST, https://climate.esa.int/en/projects/permafrost/data/) and therefore allow detailed assessment of areas with human presence over permafrost.

Cloud-top heights (CTH) from the Multiangle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra constitute our longest-running single-platform CTH record from a stable orbit. Here, we provide the first evaluation of the Terra Level 2 CTH record against collocated International Space Station Cloud-Aerosol Transport System (CATS) lidar observations between 50ºN - 50ºS. Bias and precision of Terra CTH relative to CATS, calculated from the normality of CTH error histograms, are shown to be strongly tied to cloud horizontal and vertical heterogeneity and altitude. For single-layered, unbroken, optically thick clouds observed for all altitudes, the uncertainty in MODIS and MISR CTH are -540±690 m and -280±370 m, respectively. The uncertainties are generally smaller for lower altitude clouds and larger for optically thinner clouds. For multi-layered clouds, errors are summarized herein using both absolute CTH and CATS-layer-altitude proximity to Terra CTH. We show that MISR detects the lower cloud in a two-layered system, provided top-layer optical depth < ~0.3, but MISR low-cloud errors are unaltered by the presence of thin cirrus. Systematic and random errors are propagated to explain inter-sensor disagreements, as well as to provide the first estimate of MISR stereo-opacity bias. For MISR, altitude-dependent wind-retrieval bias (-90 to -110 m) and stereo-opacity bias (-110 to -240 m) and for MODIS, bias due to low opacity near cloud-top lead to overall negative CTH bias. MISR’s precision is largely driven by wind-speed uncertainty (3.7 m s-1), whereas MODIS precision is driven by forward-modeling uncertainty.

Mantle viscosity controls a variety of geodynamic processes, e.g. Glacial Isostatic Adjustment (GIA). Constraining GIA using better viscosity estimates would improve our estimates of recent ice mass loss from the Greenland and Antarctic ice sheets and the associated sea level rise. However, mantle viscosity is poorly constrained as it can rarely be measured directly, making geophysical observations that could place constraints on viscosity more essential. Empirically, viscosity is mainly controlled by temperature, water content of nominally anhydrous minerals, partial melt, grain size and stress. Of these, temperature, water content, and the presence of partial melt can be inferred from seismic and magnetotelluric (MT) measurements, which are important tools in imaging the subsurface of the Earth. In this study, we develop a method to estimate mantle viscosity in which we: (1) constrain temperature from MT, seismic, and surface heat flow observations; (2) constrain compositional structure (i.e., water content and partial melt) from MT and seismic data coupled with experimental mineral physics data; and finally, (3) convert the calculated thermal and compositional structures into a viscosity structure. In each step, we assess and quantify the involved uncertainties. In addition, we introduce a useful parameter – the viscosity ratio (a ratio between viscosities of a target region and a nearby reference region at the same stress and grain size), and quantify its amplitude and uncertainty for a range of temperatures and water contents. We find that the uncertainty in this ratio is relatively small when computed from both seismic and MT observations, compared to either constraint applied alone. We also explore how viscosity ratio uncertainties vary with grain size and stress. Information about grain size can potentially be obtained from seismic attenuation or tectonic history. Overall, we find that both seismic and MT observations can considerably improve estimates of mantle viscosity, and place useful constraints on its lateral variations in the upper mantle. Geophysically-derived mantle viscosity models can be calibrated in areas like Scandinavia, which has well-constrained GIA models, and applied to polar regions where the GIA response is poorly known.

Studying of solar ionizing environment for the interstellar plasma inside the heliosphere is an unavoidable aspect of the interpretation of the full solar cycle of IBEX observations. We present a recent revision of the observation-based model of the ionization rates inside the heliosphere discussed by Sokół et al. 2020 (ApJ 897:179). The solar wind (SW) and the extreme ultraviolet (EUV) radiation affect fluxes of interstellar atoms inside the heliosphere both in time and in space. We present a Sun–Heliosphere Observation-based Ionization Rates (SHOIR) model based on the SW and EUV data available in solar cycle 24. We revised the in-ecliptic variation of the SW parameters, the latitudinal structure of the SW speed and density, and the photoionization rates. The revision most affects the SW out of the ecliptic plane during solar maximum and the estimate of the photoionization rates, the latter because of a change of the reference data. The changes are not constant and vary in time and in latitude. Our study shows that the polar SW is slower and denser during the solar maximum of solar cycle 24, and that the current estimates of the total ionization rates are higher than the previous ones for H, O, and Ne, and lower for He. The changes for the in-ecliptic total ionization rates are less than 10% for H and He, up to 20% for O, and up to 35% for Ne compared to the previous estimates.

The Prairie Pothole Region of North America is characterized by millions of depressional wetlands, which provide critical habitats for globally significant populations of migratory waterfowl and other wildlife species. Due to their relatively small size and shallow depth, these wetlands are highly sensitive to climate variability and anthropogenic changes, exhibiting inter- and intra-annual inundation dynamics. Moderate-resolution satellite imagery (e.g., Landsat, Sentinel) alone cannot be used to effectively delineate these small depressional wetlands. By integrating multi-temporal (2009-2018) NAIP aerial imagery and ancillary geospatial datasets, a fully automated approach was developed to delineate wetland inundation extent at watershed scales using Google Earth Engine. Machine learning algorithms were used to classify aerial imagery with additional spectral indices to extract potential wetland inundation areas, which were further refined using ancillary geospatial datasets. The wetland delineation results were then compared to the U.S. Fish and Wildlife Service National Wetlands Inventory (NWI) geospatial dataset and existing global-scale surface water products to evaluate the performance of the proposed method. The results showed that the proposed method can not only delineate the most up-to-date wetland inundation status, but also demonstrate wetland hydrological dynamics, such as wetland coalescence through fill-spill hydrological processes. The proposed automated algorithm provides a practical, reproducible, and scalable framework, which can be easily adapted to delineate wetland inundation dynamics at broad geographic scales.

Launched in October 2018, the ESA/JAXA BepiColombo mission is currently in cruise to reach Mercury in late 2025. The Mercury Orbiter Radioscience Experiment (MORE) is one of the 16 instruments hosted on board the spacecraft. Testing general relativity is among the primary objectives of MORE. Superior conjunction experiments (SCE) will be performed during the interplanetary trajectory, with the aim of obtaining an accurate estimate of the post-Newtonian parameter γ. This is allowed by MORE advanced radio tracking system which provides precise range and Doppler data almost at all solar elongation angles, thus enabling an accurate measure of the relativistic time delay and frequency shift undergone by the signal when the spacecraft is in a superior solar conjunction (SSC). The rst BepiColombo SCE will take place in March 2021, and others will follow during the cruise phase. The nal objective is to place new limits to the accuracy of the general relativity as a theory of gravity in the weak eld limit, improving previous result from the Cassini SCE (Bertotti et al. 2003), which was able to determine that γ-1=(2.1±2.3)×10-5. Because of the proximity to the Sun, the spacecraft will undergo severe solar radiation pressure acceleration, and the effect of the random uctuations of the solar irradiance may become a major concern. We address the problem of a realistic estimate of the outcome of the SCE of BepiColombo, by including the effects of solar irradiance random variations in the dynamical model. We analyzed the experiment under different assumptions on the ranging system performances, observation coverage and solar activity showing their impact on the attainable result. We propose a numerical method to mitigate the impact of the variable solar radiation pressure on the scienti c result. Our simulations show that, exploiting data from multiple SSCs, the accuracy obtainable in the relativistic time delay measurement is 13×10-6 for a strong solar activity, and 6×10-6 for weak irradiance uctuations. We found that the latter result can be obtained by the rst SSC alone if the plasma noise calibration works until the impact parameter reaches 6 solar radii.

The measurement and processing of high frequency acoustic backscatter profiles at multiple frequencies is an established technique for measuring suspended sediment load and equivalent mean particle size through the water column. The technique relies on the fact that the intensity of sound scattered by suspended particles is related not only to the particle size, but also the incident acoustic frequency. It is exploited by compact instruments that are deployed on seabed frames, vessels, and in laboratory flumes. However, one of the most significant influences on measurement accuracy comes from the presence of bubbles in the water column. Often found in suspended sediment study areas such as shallow wave-affected waters or highly turbulent flows, they can be of comparable acoustic cross-section to the suspended sediment particles and may dominate backscatter. Acoustic backscatter instrument calibrations and experimental measurements are typically carried out in a recirculating suspended sediment tower where, through careful design, a near homogeneous suspension can be established. Great attention is paid to the choice of fittings and recirculating pumps to ensure that no air is introduced into the flowing liquid, and lengthy periods of degassing are necessary to ensure no bubbles remain before measurements are taken. To tackle the problem of sediment backscatter signal contamination, a new research project is investigating how to detect and quantify bubbles present in sediment suspensions, with the aim of decomposing the backscatter signal into its sediment and bubble components. The first step in evaluating new acoustic techniques is to welcome back the bubble to the sediment tower from its long exile so it can become the focus of observations. The paper describes the recirculating suspended sediment tower and the newly introduced bubble generation and observation apparatus, which is being used to generate and observe controlled bubble populations. Bubble detection and measurement techniques are described, and initial results using a commercial acoustic backscatter profiler are presented.

Growin is a module that calculates the flux-tube-integrated linear Rayleigh-Taylor instability (grow)th rate of (i)o(n)ospheric irregularities is often used in the study of equatorial spread F(ESF). The Rayleigh-Taylor instability is often the prevailing explanation for the growth of plasma irregularities in the bottomside into plumes of depleted plasma, therefore a computation of its growth rate is valuable. This package includes many common approximations used in the computation of the Rayleigh-Taylor growth rate. Although not the focus of this discussion, Kelvin-Helmholtz instabilitiesfrom neutral wind shear below the bottomside F region are another source of plasma instability in the bottomside F region intended to be included in this package eventually.

Majority of currently applied environmental models relay on linear relations between environmental endmembers. In this research, a detailed and comprehensive comparison between linear (L) and non-linear (NL) models are presented. The L and NL models are realized in a framework of Artificial Neural Networks (ANN). The evolution process of the ANN-L and ANN-NL models is based on estimation of fractional snow cover through data-fusion between high resolution (IKONOS) and medium resolution (Landsat TM/ETM+) remotely sensed images. The statistical measure values of R2, RMSE, MAE, Accuracy, Precision, Recall, and Specificity indicate better performance of the ANN-NL model in comparison to the ANN-L in estimation of ANN Landsat-FSC. The presented results, strongly indicate that to fully capture, untangle, and characterize internal environmental relations high-sensitivity non-linear models are required. Non-linear relations are particularly visible the complex in alpine-forested environments.