UNAVCO and IRIS, major repositories for global geodetic and seismic data, are in the process of joining their operations to form a unified facility for supporting the broad spectrum of geophysical observations and science required to help understand and predict the behavior of Earth Systems. This process would be complicated in a static data management environment, but both repositories are also migrating archives and services to the cloud as part of the merger. To simplify and unify archive data management, the organizations are collaborating to create common data and metadata models for observations from a wide variety of instruments and disciplines. For data, the initial focus has been on the xArray data model, already used in the geodetic and magnetotelluric communities, which can be implemented with several disc- and cloud-native approaches (HDF5, netCDF4, and Zarr). For metadata, the SensorML Standard developed by the Open Geospatial Consortium is being explored because 1) SensorML accommodates the large parameter space associated with instrument metadata required to use and trust complex observations and 2) the ability to extend the standard when required. The merger of two large repositories combined with migration to the cloud requires careful identification and on-going testing of a wide variety of assumptions about data management systems. This presentation will focus on lessons learned so far.

This paper aimed to study the variation in the total ozone column amount (TOC) during the life cycle of the tropical cyclone (TC) that occurred over the northwest Indian Ocean in October 2008. The characteristics of TC tilts with vertically varying background flows were inspected preliminarily also in the current study. The vertical wind shear (VWS) was estimated as one of the most important dynamical parameters of the large-scale environment related to TC formation, structure, and intensity changes. It is found that the magnitude of VWS increased during the growth period, meanwhile, VWS weakened during the decay period. Anomalies of daily TOC have been calculated and found related to the strengthening of the cyclonic system. During the development of the tropical cyclone, an outflow develops in the upper levels with high velocities that can extend beyond tropopause up to the lower stratosphere. As a result, the lowest value of TOC during the tropical cyclone was owing to a large amount of injected water vapor from the troposphere into the stratosphere through the convection processes which was mostly photo-dissociated into OH plus atomic O by deep solar radiation in the upper and lower stratosphere leading to severe reduction of stratospheric ozone

The response of critically stressed dormant faults to fluid perturbation, by oil and gas production, has been a major public concern because of its link to induced seismicity. In this paper, we study the hydrogeological factors that affect a nearby fault response, during and after hydraulic fracturing (HF) operations, evaluated by the change in Coulomb Failure Stress (CFS) through coupling solid deformation and fluid flow. We take the Duvernay formation in Alberta, Canada as a base study case for our analysis. Our results show that the injection rate and the fault’s distance to HF operations play an important role in increasing the CFS and hence the probability of fault reactivation. When the fault is far from the operations, its damage zones allow lateral diffusion and prevent pore pressure build up in its upper part, which stabilizes it. The lower part, however, will be under a lower normal stress and its failure may be triggered by an increase in shear stress. This is not the case for close faults where the damage zones act as conduits for pressure diffusion and the possible triggering failure mechanism will be the increase in pore pressure. Moreover, we show that the width of the HF zone does not affect the activation mechanisms or the stability of the fault unless it is hydraulically connected to its damage zone. Therefore, serious attention should be given to the fault position, its architecture, and the volume of fluid injected to help reduce the potential for induced seismicity from HF.

Climate and sediment supply are critical factors for the sediment output of geomorphic systems. It is known that non-linearities between forcing and sediment mobilization may lead to dampened or shredded environmental signals in sediment flux measurements. But it is unclear under which circumstances environmental signals, such as extreme events or climate change, are transmitted and measurable downstream. We used a sediment cascade model and a stochastic weather generator to quantify climate forcing effects under a range of sediment supply regimes in a debris-flow catchment in the Swiss Alps (Illgraben). Sediment yields estimated from short records have high uncertainties both in terms of mean and interannual variability, and tend to be underestimated especially in supply-limited systems, where also long-term memory effects driven by sediment storage are evident. Consequently, climate change impact assessments based on short duration records may be grossly inaccurate, and should be extended with uncertainty estimation.

Changes to the eastern North Pacific tropical intraseasonal oscillation (ISO) at the end of the 21st Century and implications for tropical cyclone (TC) genesis are examined in the Shared Socioeconomic Pathways (SSP585) scenario of the Coupled Model Intercomparison Project phase 6 (CMIP6) data set. Multimodel mean composite low-level wind and precipitation anomalies associated with the leading intraseasonal mode indicate that precipitation amplitude increases while wind amplitude weakens under global warming, consistent with previous studies for the Indo-Pacific warm pool. The eastern North Pacific intraseasonal precipitation/wind pattern also tends to shift southwestward in a warmer climate, associated with weaker positive precipitation anomalies near the coast of Mexico and Central America during the enhanced convection/westerly wind phase. Implications for the modulation of TC genesis by the leading intraseasonal mode are then explored using an empirical genesis potential index (GPI). In the historical simulation, GPI shows positive anomalies in the eastern North Pacific in the convectively enhanced phase of the ISO. The ISO’s modulation of GPI weakens near the coast of Mexico and Central America with warming, associated with a southward shift of GPI anomalies. Further examination of the contribution from individual environmental variables that enter the GPI shows that relative humidity and vorticity changes during ISO events weaken positive GPI anomalies near the Mexican coast with warming and make genesis more favorable to the southwest. The impact of vertical shear anomaly changes is also to favor genesis away from the coast. These results suggest a weaker modulation of TCs near the Mexican Coast by the ISO in a warmer climate.

Due to the coupled nature of the earth system, precipitation forecast errors at S2S lead times are caused by a combination of errors/biases from the atmosphere, ocean, ice and land across a range of spatial and temporal scales. We show that UFS precipitation errors over the U.S. at Weeks 3-4 can be directly related to biases in simulating tropical dynamics. In particular, the inability of the UFS to realistically simulate the Madden-Julian oscillation (MJO) leads to biases in the teleconnection to North America that produces these errors. When the tropics are nudged to produce an accurate representation of the MJO and other tropical disturbances, U.S. West Coast precipitation biases are substantially reduced. A clustering analysis is used to show that the greatest forecast improvements with nudging occur during warm ENSO events when MJO convection is in the Indian Ocean and about to move into the Maritime Continent. Physical mechanisms that explain the improvement in tropical-extratropical teleconnections during certain MJO and ENSO states will be discussed. We will also present future plans to combine state-of-the-art developments in machine learning with process-based diagnostics of the tropical moisture and moist static energy (MSE) budgets to understand and correct precipitation biases in coupled UFS hindcasts. In particular, we will discuss how model biases and errors in tropical variability (e.g. MJO) and associated teleconnections to midlatitudes lead to errors in U.S. precipitation on S2S timescales, and present methods to reduce these errors via post-processing on a forecast-by-forecast basis.

Landsat-based monitoring of seasonal and near real-time evapotranspiration (ET) in California vineyards is currently challenged by its low temporal revisit period and missing data under cloudy conditions. Gap-filling approaches, such as data fusion with high-temporal resolution images (e.g., MODIS) and interpolation of actual to potential ET ratio (ET/ETo) between image acquisition dates are now commonly used to overcome this challenge. However, these methods may not fully capture non-linear changes in crop condition due to scheduled irrigation, and other management decisions affecting ET during days when satellite images are unavailable and can lead to biased ET estimates. In this study, we combined Landsat-8 and Sentinel-2 data to develop a Shuttleworth-Wallace (SW) based near real-time ET modeling framework for mapping daily ET across three California Vineyard sites. In addition, we utilized daily Leaf area index (LAI) products derived from the Harmonized Landsat and Sentinel-2 (HLS) surface reflectance and MODIS LAI data products to constrain key resistance parameters in the SW model and tested the model across nine flux towers covering three vineyard sites in California. Results suggest that compared to the linear interpolation-based ET/ETo approach, this framework can help reduce biases and root mean squared error of estimated daily ET by over 10%. Results point to a potential utility of the combined Landsat-8 and Sentinel-2 based approach to monitor near real-time ET and complement ongoing thermal remote sensing-based ET modeling approaches to better characterize near real-time crop water status in California vineyards.

We review the mechanisms that shape the spatial distributions of energetic electrons trapped in the magnetospheres of Jupiter, Saturn, Uranus and Neptune. To determine what controls the energy and spatial distributions throughout the different magnetospheres, we compute the time evolution of particle distributions with the help of a diffusion theory particle transport code that solves the governing 3-D Fokker-Planck equation. We discuss the processes already accounted for in our physics-based models of the outer planet electron radiation belts but also those suspected to be missing to improve our model results. Our theoretical modeling is guided by the analysis of particle, field and wave data collected by Pioneer 10&11 and Galileo at Jupiter, Cassini at Saturn, and during Voyager 2’s flyby of Uranus in January 1986 and at Neptune in August 1989.

Efficient use of available water resources is key to sustainable viticulture management in California (CA) and other regions with limited water availability in the western US and abroad. This requires remote and frequent field-scale information on vineyard water status. Though the Sentinel-2 sensors offer good spatial (10-60m) and temporal (~5 days) coverages, their utility in monitoring vineyard evapotranspiration (ET) has not been considered viable primarily due to the lack of a thermal band. However, recently, a new spectral-based Shuttleworth Wallace (SW) ET model, which uses a contextual framework to determine dry and wet extremes from the Sentinel-2 (SW-S2) surface reflectance data, has shown promise when tested over a single GRAPEX (Grape Remote-sensing Atmospheric Profile and Evapotranspiration eXperiment) site in CA. However, current knowledge on its applicability across a climate gradient in CA with different topography, soils, trellis design and vine variety is lacking. Moreover, how the selection of modeling domain and meteorological forcing data influence model output is limited. Consequently, this presentation expands the evaluation of the SW-S2 model across multiple domains and meteorological inputs covering all three GRAPEX vineyard sites spanning a north to south climate gradient over three recent growing seasons (2018-2020). In comparison with flux tower observations, the size of the modeling domain and the source and quality of meteorological forcing data on the performance of the SW-S2 model as well as application to the three different vineyard study sites will be presented. Future research on merging output from more-frequent spectral and less-frequent thermal-based ET models to reduce latency in ET monitoring of California vineyards will also be discussed.

Shear bands critically govern the shear failure processes and associated many geophysical phenomena, e.g., faulting, in Earth's crust. Earlier investigations on homogeneous materials recognized temperature and strain rate as the principal factors controlling the band growth. However, how inherent mechanical heterogeneities can influence their growth mechanism and internal structures remained unexplored. From plane-strain compression experiments on rock analogue models the present article addresses this issue. It is demonstrated from these experiments that mechanical heterogeneities dictate the failure to develop wide bands, localized preferentially in their neighborhood, unlike uniformly distributed, conjugate sets of closely spaced narrow bands in homogeneous models. The wide bands eventually attain a composite structure with a core of densely packed band-parallel sharp secondary bands, flanked by a linear zone of closely spaced, narrow bands. This study also reveals the effects of global strain-rate on the band evolution in heterogeneous systems. Decreasing strain rates replace the composite bands by well-defined homogeneous shear bands, containing a core of uniform shear, bordered by narrow zones of weak shear, grading into completely unstrained walls. Numerical modelling in a visco-elasto-plastic rheological framework under geological strain-rates is used to quantify the strain partitioning patterns in the heterogeneity-controlled transformation of spatially distributed narrow to localized, wide composite shear bands. The model simulations also reveal that increasing strain rates facilitates the bands to form clusters, instead of single wide bands. The article finally provides a set of field observations to demonstrate the importance of heterogeneity-driven band mechanics in interpreting macro-scale shear zones in geological terrains.

To investigate the subsurface structure surrounding the Main Frontal Thrust (MFT) in central Nepal, we drilled and cored sediments to depths of 45-100 m at ten sites. Our boreholes were located along previously acquired high-resolution seismic profiles across the MFT imaging the upper 1-2 km of the subsurface, which revealed a beveled erosional surface in the hanging wall above a broad, gentle anticline, as well as growth strata in the footwall. The boreholes exhibit interlayered clays, silts, sands, and gravels, dated with optically stimulated luminescence and radiocarbon to <72.5±4.3 ka, with a transition from finer to coarser sediments at ~13.5±0.1 ka. Near the fault tip, the sediments exhibit steeper dips and deformation bands. A 25-m-thick section of silt and clay above the south end of the buried anticline is interpreted as a temporary lacustrine depocenter formed due to uplift near the fault tip. Based on the distribution of marker beds and sediment ages, we interpret a shortening rate of 3.1-12.1 mm/a on the MFT. Three major transitions between fluvio-lacustrine and coarse fluvial channel facies are inferred from the boreholes, and the timings of these transitions correlate with Indian monsoonal intensity variations linked to Earth’s precession. We infer that strengthened monsoon led to increased river discharge and advance of coarse bedload-dominant braided channels, whereas weak monsoon formed a finer-grained channel environment. These monsoonal climate variations have affected the depositional environment and river base levels in this region, influencing the formation and apparent relative uplift of nearby river terraces.

Estimating the fraction of photosynthetically active radiation absorbed by vegetation (i.e., fPAR) is crucial for quantifying the carbon uptake activity of terrestrial ecosystems. Satellite-derived vegetation index (i.e., NDVI) is the powerful indicator of fPAR, enabling us to capture spatiotemporal variations in ecosystem carbon uptake activity. Since 2015, Sentinel-2 having about 3-day of revisit interval and 10 m of spatial resolution has been operated. This study evaluates the relationship between ground observed fPAR and Sentinel-2 derived NDVI in four temperate forests in Niigata prefecture, central Japan. Briefly, fPAR for April to July (from 0.44 to 0.96) varied depending on the seasons and the forest ages and types (i.e., two young mixed forests, a mature mixed forest, and a mature needleleaf forest). In the two young mixed forests and the mature needleleaf forest, NDVI was positively correlated with fPAR (r = 0.81 to 0.99), where a 0.1 increase in NDVI implied a 0.2 increase in fPAR. However, the correlation between NDVI and fPAR in the mature mixed forest was weak (r = 0.38 to 0.53). Thus, this study confirmed that the effectiveness of Sentinel-2 derived NDVI tracking spatiotemporal variations in fPAR and carbon uptake activity likely varied depending on types and ages of forests.

The immunity to slope failure is the concept that once slope failure occurs, slope failure does not recur until the soil layer recovers. It is adequate to examine whether two slope failures occurred on the same slope or not in order to verify whether the immunity to slope failures is maintained during a certain period. Two heavy rainfall the 1945 Makurazaki typhoon and the 2018 heavy rainfall occurred in the southern part of Hiroshima Prefecture, southwestern Japan in the almost same region. The aim of this study is to reveal the distribution of slope failures induced by the Makurazaki typhoon and to verify whether the immunity to slope failures is maintained during the Makurazaki typhoon and the 2018 heavy rainfall. Based on the interpretation of aerial photograph, it is revealed that the number of slope failures induced by the Makurazaki typhoon was 3,787. It is considered that the occurrence of slope failures and the amount of precipitation may be related. Areas of high slope failure density overlap in both the Makurazaki typhoon and the 2018 heavy rainfall. Thus, the immunity does not exist, or the effective period is shorter than 73 years on a mountain or watershed scale. However, 113 slope failures were caused with the 2018 heavy rainfall on the same slope where slope failure occurred with the Makurazaki typhoon, and the slope failure which recurred was only 1.4% of the whole slope failures. In addition, the length of the slope failure caused with the 2018 heavy rainfall on the same slope where slope failure occurred with the Makurazaki typhoon was shorter than that of the Makurazaki typhoon.These results suggest that the surface soil on the slope where slope failure occurred with the Makurazaki typhoon did not recover sufficiently during the period of 73 years up to the 2018 heavy rainfall, and that the immunity to the slope failure was maintained.

The recent deployment of nodal seismic instruments and DAS sensor networks has opened up a new chapter in observational seismology. Besides earthquake-generated signals, these new types of seismic array record a larger variety of low-frequency acoustic (infrasound) signals and noise than traditional instruments. Due to the near-surface deployments of these seismic sensing systems, the composition of the signals includes ground-motion sources that are associated with the atmosphere and manmade events. Meanwhile, with rapidly-growing data volumes recorded by nodal and DAS sensors, designing an automated system that detects time periods that are contaminated by these ground motions is essential. This presentation presents a comprehensive framework for the automated detection of ground-motion signals on seismic or infrasound instruments using computer vision, machine learning, and sensor fusion. Extensive experiments were conducted on Sage Brush Flats nodal array in Southern California, and our framework provides a benchmark performance for detecting aircraft events (one of the major ground-motion sources) and demonstrates the advantage of using an array of sensors. This framework is flexible and can also be extended to detecting other common types of ground motions, and to fusing other types of sensors. By combining models/systems that detect other types of ground motion, a complete characterization of the ground motions recorded by nodal and DAS sensor networks could be obtained. In addition, the data from other types of sensors such as All-Sky cameras and ADS-B or Mode S receivers could be integrated into this framework to further refine the detection performance.

Drift Orbit Bifurcation (DOB) has been suggested to play a major role in the loss and transport of radiation belt electrons since it violates the second and third adiabatic invariants of particles. Results from our guiding-center test particle simulations using the Tsyganenko-1989c magnetic field model show that the DOB could affect a broad region of the outer radiation belt, which can penetrate inside the geosynchronous orbit at Kp ≥ 3, and its effects are more significant further away from Earth, at higher Kp, and for higher electron energies. Specifically, the short-term simulation results after one electron drift show both traditional and nontraditional DOB transport of electrons, with the nontraditional DOB, caused by a third minimum of the magnetic field strength near the equator, reported here for the first time. Moreover, our results show large ballistic jumps in the second invariant and radial distance for electrons at high equatorial pitch angles after one drift. In addition, long-term DOB transport coefficients of electrons over many drifts are calculated based on our simulation results. We find that the pitch angle and radial diffusion coefficients of electrons due to DOB could be comparable to or even larger than those caused by electron interactions with chorus and ULF waves, respectively. In sum, our results demonstrate that DOB could cause effective loss and transport of radiation belt electrons even in the absence of waves.

Streambed inhabitants mix and mobilize sediments by actions such as burrowing, feeding, and excretion, a process referred to as sediment reworking. This sediment-organism interaction could modify the hydro-physical properties of streambeds and significantly influence the hyporheic flow regime in streams as highlighted by our recent research. In this work, we further advance the understanding of the sediment reworking process by investigating the influence of the organism size on the modification of streambed properties and hyporheic exchange. Laboratory experiments were conducted in long recirculating flumes to simulate streamflow environment and Lumbriculus variegatus of two different sizes (large worms were double the thickness of small worms) were used as model organisms. The organisms of both sizes were allowed to rework the sediment beds in their respective flumes for 10 days after which dye tracer tests were performed to characterize hyporheic exchange flows. Visual observations reveal that the burrow openings at the bed surface were readily visible in the flume reworked by larger organisms compared to the flume reworked by organisms of smaller size. The former also exhibits higher hyporheic flux and shorter residence times compared to the latter which could be attributed to the rapid exchange of solutes across the streambeds due to the presence of a dense network of voluminous burrows. The exchange depths in both the flumes were similar and a potential reason for this observation could be the reworking of sediment beds up to similar depths in the flumes. We suggest that further exploration must be done at both small and large scales to comprehend the role of sediment-organism interaction in modulating hyporheic exchange flows as it will have direct implications on critical stream ecosystem services such as natural processing of nutrients and contaminants.

During Marine Isotope Stage 3 (MIS-3; 57–29 ka) Antarctic ice cores reveal a glacial climate state punctuated by millennial-scale warming events and pulses of CO2. Changes in iron-fertilised export production and ocean circulation/upwelling, interpreted from South Atlantic sediment cores, suggest that the Southern Ocean is a conduit for the storage and release of CO2 from the deep ocean. However, it is unclear whether this occurs throughout the Southern Ocean as these processes have not previously been investigated in the southwest Pacific . Here we describe localised iron limitation linked to glaciation changes in New Zealand, which reduced export production during early MIS-3 (60–48 ka) and caused decreases/increases in export production during late MIS-3 (48–29 ka) millennial-scale warming/cooling. Consistent decreases in foraminifera-bound δ15N during all MIS-3 warming events may reflect changes in the supply of nitrate to the subantarctic Pacific, possibly from increased wind-driven upwelling in the Antarctic and northward eddy-driven transport and/or shifting SO fronts. Concomitant decreases in bottom water oxygen and increases in the 14C age of deep waters suggest that old, nutrient-rich waters influenced upper circumpolar deep water in the southwest Pacific during warming events. This signature may reflect an expansion of Pacific Deep Water into the Southern Ocean as Southern Ocean overturning strengthens. Iron-limitation of export production, the expansion of Pacific Deep water, and increased wind-driven upwelling would all work to contribute to increasing atmospheric CO2 through reduced drawdown, and increased outgassing from the Pacific carbon reservoir during the millennial-scale warming events of MIS-3.

1. Freshwater phytoplankton communities are currently experiencing multiple global change stressors, including increasing frequency and intensity of storms. An important mechanism by which storms affect lake and reservoir phytoplankton is by altering the water column’s thermal structure (e.g., changes to thermocline depth). However, little is known about the effects of intermittent thermocline deepening on phytoplankton community vertical distribution and composition or the consistency of phytoplankton responses to varying frequency of these disturbances over multiple years. 2. We conducted whole-ecosystem thermocline deepening manipulations in a small reservoir. We used an epilimnetic mixing system to experimentally deepen the thermocline in two summers, simulating potential responses to storms, and did not manipulate thermocline depth in two succeeding summers. We collected weekly depth profiles of water temperature, light, nutrients, and phytoplankton biomass as well as discrete samples to assess phytoplankton community composition. We then used time-series analysis and multivariate ordination to assess the effects of intermittent thermocline deepening due to both our experimental manipulations and naturally-occurring storms on phytoplankton community structure. 3. We observed inter-annual and intra-annual variability in phytoplankton community response to thermocline deepening. We found that peak phytoplankton biomass was significantly deeper in years with a higher frequency of thermocline deepening events (i.e., years with both manipulations and natural storms) due to weaker thermal stratification and deeper depth distributions of soluble reactive phosphorus. Furthermore, we found that the depth of peak phytoplankton biomass was linked to phytoplankton community composition, with certain taxa being associated with deep or shallow biomass peaks, often according to functional traits such as optimal growth temperature, mixotrophy, and low-light tolerance. 4. Our results demonstrate that abrupt thermocline deepening due to water column mixing affects both phytoplankton depth distribution and community structure via alteration of physical and chemical gradients. In addition, our work supports previous research that phytoplankton depth distribution and community composition interact at inter-annual and intra-annual timescales. 5. Variability in the inter-annual and intra-annual responses of phytoplankton to abrupt thermocline deepening indicates that antecedent conditions and the seasonal timing of surface water mixing may mediate these responses. Our findings emphasize that phytoplankton depth distributions are sensitive to global change stressors and effects on depth distributions should be taken into account when predicting phytoplankton responses to increased storms under global change.