A careful characterization of moisture fluxes and saturation-ratio statistics in atmospheric convection is significant for cloud microphysical processes and dynamics. The saturation-ratio of water vapor is defined as the ratio of actual water vapor pressure and its equilibrium value at a given air temperature. Therefore, it is a function of two scalars (water vapor and temperature) and is coupled through the nonlinear Clausius-Clapeyron equation. Participation of both scalar fields in the convection process and the nonlinear coupling of both scalars in saturation-ratio make this problem more complex, as compared to its dry-convection counterpart. We have explored heat and water vapor fluxes and saturation-ratio statistic in the moist Rayleigh-Bénard convection case, using the one-dimensional-turbulence (ODT) model developed by Wunsch et al. JFM 2005. This idealized small-scale simulation is a step toward understanding the full atmospheric convection problem at a more fundamental level. We have obtained the thermal and moisture fluxes as a function of the non-dimensional buoyancy parameter, also known as moist Rayleigh number, and compared it with the scaling relations. Moreover, we have examined the mean and variance profiles of saturation-ratio, and analyzed the different contributing terms for saturation-ratio fluctuations. Based on the scaling analysis, a simplified relation between saturation-ratio variance and moist Rayleigh number has been derived and compared with the simulation results. Additionally, we found that different values of water vapor and thermal diffusivities make the saturation-ratio pdf broader than the case when they are considered equal.

Hydro climate services, such as early warning systems and monitoring and forecasting services for floods and droughts, are required to deal with climate risk management and adaptation. Those tools also contribute to achieving international goals and commitments such as Sustainable Development Goals (SDGs), the Paris Agreement and the Sendai Framework for Disaster Risk Reductions. Recognizing these needs, UNESCO’s International Hydrological Programme (IHP) has fostered the creation and application of many such products in recent years. This has been accomplished through unique formal and informal partnerships among IHP programs, such as the Global Network on Water and Development Information for Arid Lands (G-WADI) and the International Flood Initiative (IFI); UNESCO regional and country offices in Africa, Latin America and Asia; university engineering and hydrology departments; and UNESCO’s network of affiliated (“category 2”) centers, such as the International Center for Integrated Water Resources Management (ICIWaRM) and the International Centre for Water Hazard and Risk Management (ICHARM). The presentation will include an overview of the products, tools and services developed through these collaborations among IHP and its “water family” and their effectiveness in providing such services to Member States.

Ash-producing volcanic eruptions are a major natural hazard and the magnitude of the explosivity of these eruptions have been indicated for decades by a semi-quantitative “Volcanic Explosivity Index (VEI)” based on a number of interdependent factors, (eruption duration, volume of ejected material, eruptive column height, tropospheric and stratospheric injection, and qualitative descriptors). We present a simple empirical formulation for a fully quantitative VEI (𝑉𝐸𝐼Hc), based solely on eruption column height. This method directly translates the height of the eruption column into VEI, a useful formulation for immediate understanding of the explosivity of eruptions as they are taking place. This new scale is calibrated for convenience and familiarity to span the same range of values as the existing, semi-quantitative, VEI scale. In addition to being a simple and quantitative approach, this new method, translating column height directly into VEI, has the advantage of being calculated in real time during an eruption. This will improve immediate response by aviation, hazard management, and others to mitigate societal impact of hazardous eruptions.

Computational geoscience courses often combine domain science, math, programming, and hardware instrumentation. Ensuring students master all those skills can be daunting for professors, as well as for students who tackle these hybrid classes. Through a series of 3-day in-person workshops, faculty across the geoscience disciplines and allied science fields have collaborated to produce on-line teaching resources and a community of peers to support these multi-faceted but essential Geoscience courses. These resources support Geoscience and Science educators seeking to update their curriculum and even create whole new courses. Topics addressed include approaches to teaching, best practices for working group design, empowering students to self-advocate, building computational skills optimally, and coordinating curriculum across a department and even cross-departments. This e-lightning talk will show the resources available to educators – teaching activities including MATLAB code, presentations on teaching approaches, and course curriculum, among others. It will also highlight relevant MathWorks tools for learning and teaching, from online videos, to free, interactive MATLAB tutorials (MATLAB Onramp and more), to autograding software for MATLAB code (MATLAB Grader), with associated publicly available homework problem sets. Attendees will learn where and how to access these online resources, share their teaching challenges, and participate in future workshops.

We live in an “Ice House” world that has extensive ice cover at both poles. However, it has not always been this way. During the last 540 million years there have been only 4 other time intervals characterized by extensive polar ice caps (latest Ordovician, latest Devonian, Permo-Carboniferous, and late Cenozoic). The combined duration of these frigid intervals was approximately 160 million years, or ~30% of Phanerozoic history. During the remaining 380 million years the Earth lacked permanent polar ice caps, though some winter snow and ice may have accumulated at high latitudes during cool, greenhouse intervals (Silurian-early Devonian, late Jurassic – early Cretaceous). The modern ice house world is probably the most severe of all ice house worlds because it is the only time in Earth history when the North and South polar regions were concurrently glaciated. Using the compilation of lithologic indicators of glacial conditions (tillites, dropstone, & glendonites) compiled by Boucot et al. (2013), I have mapped the areal extent of polar ice caps (millions of km2) for the time periods when ice house conditions prevailed. Using a simple algorithm that estimates the thickness of the ice based on the total area of the ice cap, I have calculated the corresponding volume of continental ice (millions of km3) for each of these time intervals. Converting solid ice to liquid water, the equivalent volume of evaporated ocean water was calculated. Expressed as a percentage of the present-day volume of ocean water (1.35 billion km3), I estimated the amount of water removed from the oceans during each of these ice house intervals. Preliminary results, indicate that the five largest ice volume events were the Hirnantian (444.5 Ma) – 2%, Modern World – 2%, Pliocene (3 Ma) – 2%, early Permian (280 Ma) – 1.5%, and late Miocene (10-15 Ma) – 1.4%. Since the water removed from the oceans by evaporation is preferential enriched in 16O, it is possible to calculate the resulting δ18O of the remaining oceanic reservoir. These calculations may be useful when estimating paleotemperatures from the δ18O record of fossil organisms.

Methane fluxes are often studied using eddy covariance flux towers or chambers placed on the soil surface. These measurement techniques have improved our understanding of methane emissions from wetlands. However, there are limitations with each measurement method. For example, chambers are fixed in place and have high maintenance costs, limiting spatial coverage and characterization of heterogeneity. Measurements taken in Interior Alaskan wetlands suggest that heterogeneity in methane fluxes from this region may increase during the fall and early winter, when the soils begin to freeze. Unfortunately, off-grid power limitations and freezing conditions complicate chamber operation during this time. Towers share similar demands with respect to maintenance and cost of operation, and, therefore, are not often replicated within a landscape. Moreover, towers provide an integrated measurement which masks any spatial heterogeneity in fluxes within the tower footprint. Therefore, although chamber and flux towers provide important insights into the carbon exchange between terrestrial and atmospheric pools, these methods have limitations, particularly when characterizing spatial heterogeneity. We tested a new technology that may be able to be counteract some of these limitations, thereby providing additional insights into methane emissions from wetlands. We outfitted a small-unmanned aerial system (sUAS, or drone), that can fly extremely close (<2 m) to the wetland’s surface, with a miniature open-path laser spectrometer methane sensor, LIDAR, and a miniature anemometer. We then tested this system in several bogs near Fairbanks, Alaska. We tested if this system could detect spatial and/or temporal variability of methane emissions within a bog. We also compared methane fluxes calculated using this system to values obtained from tower and chamber measurements. Results of these missions will be presented and we will discuss the ability of this new technology to provide additional information regarding methane emissions from wetlands.

The Global Learning and Observations to Benefit the Environment (GLOBE) Program is an international science and education program that connects a network of communities around the world and gives them the opportunity to participate in data collection and the scientific process, and contribute meaningfully to our understanding of the Earth system and global environment. GLOBE hosts the GLOBE International STEM Network (GISN), which is an international network of STEM professionals that work with GLOBE students, teachers, and other STEM professionals around the world. Members of the GISN may mentor students and teachers, collaborate on scientific research, use GLOBE data in their research, judge student research projects, and write blogs for the GLOBE website, among other things. In January 2018, the GISN, which was previously only open to graduate students and seasoned STEM professionals, was expanded to include “Early Career STEM Professionals” which includes upper-level undergraduates or master’s students pursuing a degree in a STEM field or recent graduates working in STEM fields but have less than five years’ experience. Goals for expanding the the GISN include granting early career professionals a chance to establish ties with the next generation of STEM professionals, connecting early career professionals and students with potential mentors and collaborators, and allowing early career professionals and students to explore what a career in a STEM field can look like. All GISN members will benefit from an increase in the number of members as well as an increase in the numbers of members who have more flexibility in terms of time and finances. As well, it is another opportunity for GLOBE to engage with alumni of the program who have continued a career in STEM. Unlike other ECS networks, the GISN does not separate the ECS’ out from the other members so all members have equal access to resources and each other. Since opening up the GISN in January, 17 Early Career STEM Professionals representing 5 of our 6 regions (Africa, Asia and the Pacific, Europe and Eurasia, Latin America and the Caribbean, and North America, but not Near East and North Africa) have joined the network bringing total membership to 421 members.

Land use change due to population growth and an increase in anthropogenic activities such as logging and mining (mostly illegal) have led to an increase in the sediment load of the Kasai River in the Congo River Basin. However, even with recent developments in technologies such as remote sensing and improvements in erosion prediction models to study sediment transport in water bodies; this phenomenon has been little studied in this poorly gauged catchment and the wider Congo River Basin due to lack of field-based sediment concentration measurements required to calibrate the results of such studies. The present study describes recently concluded field excursions to set up a high frequent sediment sampling station on one of the major tributaries of Congo River, the Kasai River. The station is fitted with an ISCO 6712 automatic pumping sampler to enable high frequency sampling. The ISCO is coupled with an OBS 501 turbidity sensor to collect even higher frequent sediment concentration data. The site is also fitted with other instruments to measure other hydrologic and climatic variables such as a manual staff gauge and an automatic water levels logger. The preliminary sampling efforts have been designed to guide a comprehensive sediment sampling programme which is part of a wider study to build a sediment yield model for the Congo River Basin in order to study the impacts of sedimentation on hydropower planning.

Apatite (U-Th)/He (AHe) thermochronology depends on accurate knowledge of how diffusion occurs. This involves measurement of core diffusion kinetics as well as understanding the behavior of migrating He atoms. Drawing from previous studies as well as data obtained via continuous ramped heating (CRH), we assess several processes that need to be integrated into a single model for He diffusion in apatite. CRH analyses conducted at different heating rates show a kinetic response for both the “normal” lower-temperature and the higher-temperature release peaks, with peaks shifting to lower temperatures at lower heating rates. Where we do see a rollover in Arrhenius trends it also shows a kinetic response, being deferred to higher temperatures at higher heating rates, though many samples with unimodal release peaks do not show a significant rollover; fluorapatites seem to show more prominent rollover. For samples showing multiple release peaks, we find that their Arrhenius data often transition from one lower-temperature trend to another at higher temperatures that has about the same slope and thus activation energy. This looks very much like MDD behavior in K-feldspar, and MDD domain analysis fits the observed data very well, even if mechanisms involving discrete domain sizes are implausible. This interesting and unexplained result must speak to the nature of what is happening during analysis of samples having trapped He. To explore our data, we coded a simple diffusion model in which single He atoms are free to jump within a grid, but can also arrive at grid nodes designated as reversible sinks, escape from which depends on an exponentially temperature- dependent probability. The model includes radiogenic He production over geological thermal histories followed by laboratory CRH outgassing. When conditioned using D values observed for AHe, the model accurately predicts parameters such as closure temperature and fractional loss. When traps are introduced, the model simulates the essential nature of the dual-peak CRH results we see. Three important results emerge from this model. (1) Few sinks need be present. (2) Trapping occurs twice during diffusion, first in nature and then again during laboratory outgassing, meaning that the ratio of the gas amounts beneath each CRH peak overestimates the geological trapping. (2) Trapping in nature is very dependent on the sample’s thermal history: it is smallest for ancient rapid cooling and largest for samples that reside in the PRZ (allowing more radiogenic production to find traps before diffusion ceases). This model raises the possibility that complex CRH data record extended thermal-history information. If CRH and 4He/3He analysis were combined the 3He lab outgassing would record the sample’s trapping dynamics, and the 4He outgassing would reflect that plus a segment of the sample’s thermal history, which could be extracted using the 3He observations.

Paleotempestology assists in extending the instrumental storm record through sedimentary-based, high-resolution records of storms over millennia. A fundamental understanding of the paleorecord provides essential context for modern climate models and, therefore, a broader understanding of our climate system. The Texas (TX) coastline receives the second largest number of hurricane landfalls per year in the United States; since 1900, 92 tropical storms and hurricanes have made landfall on the TX coast. During storm impacts, coastal downwelling storm channels deliver coarse sediment to the muddy shelf. This return flow or “backwash” process results in thin but expansive storm deposits in the region, making it ideal for paleotempestological reconstructions. In this work, three sediment cores from the central TX shelf, approximately six kilometers off the coast of Matagorda Island, were collected and analyzed. Several historic and Holocene storm events have been identified in cores by conducting detailed grain size analysis at one-centimeter intervals. Bayesian-based age models couple short-lived isotopic dating techniques (210-Pb and 137-Cs) with radiocarbon ages. X-ray fluorescence (XRF) analysis is used to determine geochemical signatures of the sediments and thus the material source for cross validating the depositional mechanism. Specifically, XRF is utilized to differentiate the effects of the 1929 Colorado River diversion relative to marine deposition. Our new record of tropical cyclone (TC) occurrence from the TX shelf is compared to paleoclimate models and proxy records of El Niño Southern Oscillation (ENSO) and Gulf of Mexico (GOM) sea surface temperature (SST). Preliminary results suggest that periods of decreased ENSO and increased GOM SST correspond with enhanced TX TC activity. Understanding these complex climatic interactions will help us to understand the changes in TC activity expected in the future against the background of accelerating climate change. Given that the frequency of extreme ENSO events is projected to increase, changes in the occurrence and severity of ENSO-TX TC events may prove detrimental to many coastal populations.

Apatite – Ca5(PO4)3(OH,F,Cl) – is a common accessory mineral in many terrestrial rocks and has a low (~75˚C) closure temperature for He retention[1]. As such the (U-Th-Sm)/He thermochronometer has become one of the most used dating techniques to constrain low temperature cooling histories of terrestrial samples. Apatite has been documented in many meteoritic, lunar, and martian samples, and is a particularly common accessory phase in many martian lithologies[2]. In meteoritic samples, (U-Th-Sm)/He dating of apatites provides some methodological challenges in that grains are frequently anhedral making it complicated to do a FT correction[2]. Results are commonly interpreted to represent the timing of shock metamorphism related to impacts onto the (planetary) surface which often correlates with cosmic-ray exposure ages[2]. NWA 7034, and its pairings, represents a piece of martian regolith that documents events on the martian surface that span approximately 4 Ga[3]. NWA 7034 is known to contain upwards of 4 wt.% apatite as detrital mineral fragments and as accessory phases in many lithic and impact-derived clasts[4]. These apatites have been previously analyzed geochronologically via U-Pb apatite and isotopically via δD, δ37Cl, and H2O using microbeam techniques[5,6]. At present, (U-Th)/He dating of NWA 7034 and its pairings has been restricted to bulk rock analyses[4,7,8,9]. This whole-rock approach relies on assumptions that the He, and its parent isotopes, are evenly distributed throughout the sample and that resetting of the WR-He thermochronometer is universal throughout the sample in response to the thermal pulse associated with the impact. These studies have yielded widely dispersed datasets that range from 50 Ma to 200 Ma, putting some of those assumptions into question[4,7,8,9]. In this contribution, we utilize the laser ablation double-dating (LADD) technique on individual apatites present within several polished slabs of NWA 7034. This targeted approach allows us to acquire (U-Th-Sm)/He ages, U-Pb ages, and trace element information within a petrological framework. The (U-Th-Sm)/He ages will provide additional constraints on the low temperature history of NWA7034 and help test the veracity of WR-He retention ages. References: [1] Zeitler et al. 1987 GCA, [2] Min 2005 Rev. Mineral Geochem; [3] Cassata et al. 2018, SciAdv; [4] Agee et al. 2013 Sci; [5] Hu et al. 2019 MAPS; [6] Davidson et al. 2020 EPSL; [7] Cartwright et al. 2014 EPSL; [8] Lindsay et al. 2021 MAPS; [9] Stephenson et al. 2017 MAPS

In the energy transition context, the design of integrated multi-energy systems is key for reaching ambitious sustainability objectives. Due to the intermittent nature of the renewable energy sources, introducing technologies for storing and transforming energy in different carriers (e.g., electricity, gas, heat) is, in fact, a strategic solution for fully exploiting the renewable power generation, increasing the flexibility of the system, and contributing to the decarbonization. Although the need to rely on multi-energy systems is widely shared, identifying their optimal design requires the use of complex modelling tools able to characterize the territory, simulate the system dynamics, and evaluate the solutions with respect to different sustainability objectives. To support the decarbonization decision-making process, in this work we develop a three-step modelling chain for planning optimal multi-energy systems at the local scale. More precisely, we first perform a territory characterization by estimating, through different methodologies, input data of renewable resource availability, territory exploitation potential, and energy demand of electricity and heat. Then, we carry out a multi-energy analysis identifying Pareto optimal system designs with respect to two sustainability objectives, namely the Net Present Cost and the CO2 emissions. Finally, we perform an intersectoral Multi Criteria Analysis-Cost Benefit Analysis (MCA-CBA) for evaluating the solutions obtained in the previous step with respect to a wide range of indicators representing energy, economic, and social acceptance aspects. The CBA approach is adopted for evaluating the financial and economic viability of the investment options, while the assessment of non-monetary impacts is performed through the MCA approach. We apply the modelling chain to the real case study of Sulcis Iglesiente (Sardinia, Italy), a territory characterized by carbon-intensive industries, recently selected for receiving funding from the Just Transition Fund launched by the EU Commission in the context of the Green Deal. Expected results aim to demonstrate the validity of the proposed modelling chain in the identification of the best interventions for supporting the decarbonization and the sustainable development of Sulcis Iglesiente.

Low marine clouds are a major source of uncertainty in cloud simulations across models from LES to global scale. To address this issue, we conducted Lagrangian LES experiments that explore the aerosol-cloud interactions for case studies covering a spectrum of observed ambient conditions, and evaluated the model against observations. Our LES benefits from a prognostic aerosol model that simulates aerosol budget tendencies such as coalescence and interstitial scavenging, surface sources, and entrainment from free troposphere. To initialize, force, and evaluate the LES, we used a combination of reanalysis, satellite, and aircraft data from the Cloud System Evolution in the Trades (CSET) field campaign in summer 2015 over the Northeast Pacific. The LES follows two Lagrangian trajectories from subtropical stratocumulus (Sc) deck region offshore of California to tropical shallow cumulus (Cu) region near Hawaii. The first trajectory is characterized by a clean, well-mixed Sc-topped marine boundary layer (MBL) on the first day, and continuous MBL deepening and precipitation onset after the first day followed by a clear Sc-to-Cu transition (SCT) and a consistent reduction of aerosols that ultimately leads to an ultra-clean layer at the top of MBL. Overall, the LES simulates general MBL features seen in observations. The runs with enhanced aerosols show distinct changes in microphysics and macrophysics such as delayed precipitation onset and SCT. The second trajectory is characterized by an initially polluted and decoupled MBL, weak or no precipitation, and no clear sign of SCT throughout the simulations. It is challenging for LES to simulate observed features, and the LES underestimates (overestimates) low cloud fraction in the first (last) day. Although enhancing aerosols among cases leads to distinct changes in microphysics (e.g., enhancement of cloud optical depth and reduction of effective radius), it does not affect cloud macrophysical properties significantly. Finally, a theoretical analysis was conducted to decompose contributions to albedo of the Twomey effect and cloud adjustments. The cloud radiative forcing due to the Twomey effect shows an enhancement with an increase in aerosol, however, the cloud radiative forcing due to cloud adjustments is strongly dependent on ambient meteorological conditions.

A gap in community practice on data citation that emerged during the AGU fall meeting 2020 Data FAIR Town Hall, “Why Is Citing Data Still Hard?” with the goal of addressing the use case of citing a large number of datasets such that credit for individual datasets is assigned properly. The discussion included the concept of a “Data Collection” and the infrastructure and guidance still needed to fully implement the capability so it is easier for researchers to use and receive credit when their data are cited in this manner. Such collections of data may contain thousands to millions of elements with a citation needing to include subsets of elements potentially from multiple collections. Such citations will be crucial to enable reproducible research and credit to data and digital object creators. To address this gap, the data citation community of practice formed including members from data centres, research journals, informatics research communities, and data citation infrastructure. The community has the goal of recommending an approach that is realistic for researchers to use and for each stakeholder to implement that leverages existing infrastructure. To achieve data citation of these subsets of large data collections the concept of a “reliquary” is introduced. In this context the reliquary is a container of persistent identifiers (PIDs) or references defining the objects used in a research study. This can include any number of elements. The reliquary can then be cited as a single entity in academic publications. The reliquary concept will enable data citation use cases such as the citation of elements within a data collection that are formed from numerous underlying datasets that have their own PIDs, unambiguous citation of data used in IPCC Assessment Reports, and citing the subsets of collections of research data that contain millions of elements. The discussions over the course of 2021 have developed a theoretical concept, at the time of writing formal use cases and initial applications are being defined. The recommendation developed by this effort will be available for review and comment by communities such as ESIP and RDA. All are welcome.

The southeast Atlantic Ocean provides an excellent natural laboratory to study smoke-cloud interactions, a large driver of uncertainty in climate projections. The value of studying this in particular region is largely attributable to two factors---the expansive, bright, semi-permanent stratocumulus cloud deck and the fact that southern Africa is the largest source of biomass-burning aerosols in the world. We study this region using the WRF-Chem model with CAM5 aerosols and in situ observations from the ORACLES, LASIC, and CLARIFY field campaigns, all of which overlapped in August 2017. Across these campaigns, we compare aerosol, cloud, and thermodynamic variables to quantify model performance and expand upon observational findings of aerosol-cloud effects. Specifically, our approach is to analyze aerosol and cloud properties along flight tracks, picking out uniform legs within tropospheric smoke plumes and in the boundary layer. This unique approach allows us to sample the high spatiotemporal variability that can get lost to large-scale averaging. It also allows process-level comparison of local cloud responses to aerosol conditions, and measure model performance in those same processes. Along with better quantifying model predictive power, we find and justify updates to model parameters and processes to better emulate observations, notably aerosol size parameters. Preliminary results suggest that WRF-CAM5 is activating a smaller percentage of aerosols into cloud droplets than shown in observations, which could lead to biased modeling of aerosol indirect radiative effects on a larger scale. We explore this effect further with CCN activation tendency, updraft, particle sizing, and composition analysis, as well as broader dynamics like entrainment and removal rates. Comparing the model with similar instrument suites across multiple colocated campaigns also allows us to quantify instrument uncertainty in ways that a focus on a single campaign cannot and gives further context to the model performance.

As part of NASA’s Earth Science Technology Office, the Advanced Information Systems Technology (AIST) Program defines an Earth System Digital Twin (ESDT) as an interactive and integrated multidomain, multiscale, digital replica of the state and temporal evolution of Earth systems that dynamically integrates: Relevant Earth system models and simulations Other relevant models (e.g., related to the world’s infrastructure and human activity); continuous and timely (including near real time and direct readout) observations (e.g., space, air, ground, over/underwater, Internet of Things (IoT), socioeconomic) Long-time records Analytics and artificial intelligence tools. Effective ESDTs will enable users to run hypothetical or “what-if” scenarios to improve the continuous assessment and prediction of Earth system processes, natural phenomena and human activities as well as their many interactions, and to ensure optimal mitigation and response to these phenomena. Toward this goal, the AIST Program is developing individual technologies and a few pilots. Some of the technologies that are being considered include: agile interoperability between measurement acquisition and science investigations; moving from mono-discipline to multi-discipline interconnected models; digital thread developments to provide communication links to all digital twin capabilities and to enable design requirements, records, provenance, and system reconfigurations to be easily coordinated; concepts and technologies for developing “federated ESDTs”; multi-scale simulations, statistics, uncertainty quantification, and causality methodologies; high-end computing and surrogate models to optimize the computational efficiency of “what-if” investigations; and innovative user interfaces and visualization methods capable of visualizing complex systems of systems.

The entire western US is in the midst of a megadrought. Combined with high temperatures, increasingly severe droughts are causing widespread forest mortality. In the Sierra Nevada, CA in particular, the Mediterranean climate exposes montane forests to water stress due to the summer drought. Normally, the slow melting of the winter snowpack helps to alleviate summer water stress, especially in riparian ecosystems that benefit from subsurface lateral inputs along a hillslope. However, the loss of the snowpack due to snow drought could potentially eliminate these buffering effects. This research aims to address the role of subsurface lateral redistribution in mediating vegetation responses to drought along a hillslope. We apply a spatially-distributed ecohydrologic model (RHESSys) to an experimental hillslope in a snow-dominated watershed in the Sierra Nevada, CA. We incorporate observed sap flow data from the experimental hillslope to estimate the relative differences in onset of water stress for upslope and riparian sites, which is used to constrain RHESSys drainage parameter uncertainty. Then, we run hypothetical multi-year drought experiments to investigate how climate variability translates to water stress on a hillslope. Our results challenge the common assumption that riparian forests are buffered against drought stress by subsurface lateral inputs. For all drought types, both upslope and riparian sites experience severe losses of net primary productivity (NPP), and on average upslope sites are more adversely affected (upslope loss of NPP = 50% vs. riparian = 35%). But even in a wet year, as temperatures rise and the snowpack disappears (i.e., warm snow drought), vegetation approaches a threshold response that destabilizes the riparian buffering effect. Our results show that for 12% of all scenarios, riparian NPP decreases more than upslope NPP, as a consequence of earlier snowmelt. Interactions between climate variability and ecophysiological uncertainty produce scenarios that exhibit the riparian threshold response. By recognizing the conditions that determine riparian sensitivity to drought, management actions can be proactive in preserving this important hydrological refugia.

Virtual reality (VR) is an important tool for several applications in science, industry, and education. Previous studies have already shown how the use of VR at full scale is an effective tool for outcrops characterization even at centimetre scale [1]. We aim to extend the use of this approach in various fields of planetary exploration, from outcrop to regional scale. This regional approach may provide an effective support for the planning and management of future missions, but also for geological and geomorphological studies and mapping. Among the most obvious advantages of the use of virtual reality are the lack of optical deformations and approximate dimensions of the two-dimensional display (such as display, projections and printed cartography) and the opportunity to layer various levels of information through a new concept of superposition. The VR environment is derived from several multi-scale elements: medium to high-resolution elevation data, photogrammetric 3D models, orthophotos, multispectral data, thematic maps and vector data transformed into three-dimensional digital representations placed in the study context. The first tests are based on stereogrammetry (using USGS ISIS [2] and NASA ASP [3]) of the lunar LRO (LROC-NAC) [4] and Martian MRO (CTX and HiRISE) [5] and MEX (HRSC) [6] missions and on data and cartography realized through external open-source GIS tools (GDAL libraries, QGIS, GRASS) and virtual tools developed to be used within the VR environment. In our tests, for example, the Rock Abundance analysis results have been shown not only as thematic maps but also as digital representations of floating boulders on the surface. This has been achieved by placing major rock elements (>1m) in the position detected from satellite imagery and smaller elements, estimated from size-frequency distributions studies, with a preliminary semi-random distribution. References [1] Mouélic S. L. et al. (2019), Geophys. Res. Abstr, Vol. 21. [2] Becker K. J. et al. (2013), LPSC, Vol. 44. [3] Moratto Z. M. et al. (2010), LPSC, No. 1533, p. 2364. [4] Robinson M. S. et al. (2010), Space Sci. Rev., 150: 81-124. [5] McEwen A. S. et al. (2007), J. Geophys. Res. Planets, 112.E5 [6] Neukum G. & Jaumann R. (2004). Mars Express: The Scientific Payload, Vol. 1240, pp. 17-35.