Assessment of bottom-up greenhouse gas emissions estimates through independent methods is needed to demonstrate whether reported values are accurate or if bottom-up methodologies need to be refined. Previous studies of measurements of atmospheric methane (CH4) in London revealed that inventories substantially underestimated the amount of natural gas CH4 1,2. We report atmospheric CH4 concentrations and δ13CH4 measurements from Imperial College London since early 2018 using a Picarro G2201-i analyser. Measurements from May 2019-Feb. 2020 were compared to the values simulated using the dispersion model NAME coupled with the UK national atmospheric emissions inventory, NAEI, and the global inventory, EDGAR, for emissions outside the UK. Simulations of CH4 concentration and δ13CH4 values were generated using nested NAME back-trajectories with horizontal spatial resolutions of 2 km, 10 km and 30 km. Observed concentrations were underestimated in the simulations by 12 %, and there was no correlation between the measured and simulated δ13CH4 values. CH4 from waste sources and natural gas comprised of 32.1 % and 27.5 % of the CH4 added by regional emissions. To estimate the isotopic source signatures for individual pollution events, an algorithm was created for automatically analysing measurement data by using the Keeling plot approach. Over 70 % of source signatures had values higher than -50 ‰, suggesting large amounts of natural gas CH4. The analyses based on model-data comparison of δ13CH4 and on Keeling plot source signature emission both indicate that emissions due to natural gas leaks in London are being under-reported in the NAEI. These results suggest that estimates of CH4 emissions in urban areas need to be revised in the CH4 emissions inventories. 1 Helfter, C. et al. (2016), Atmospheric Chemistry and Physics, 16(16), pp. 10543-10557 2 Zazzeri, G. et al. (2017), Scientific Reports, 7(1), pp. 1-13

The research on increased ductility of organic-rich shale and its impacts on hydraulic fracturing has received relatively little attention. According to recent experimental studies, the popular cohesive zone model that only features decreasing traction along with crack separation may not adequately represent the crack behavior in shale due to ample organic matter. This paper starts by proposing a modified cohesive zone model that can represent various traction-separation laws (TSL) within a unified formulation. Then a fully coupled poroelastic XFEM framework to simulate hydraulic fracturing in organic-rich shales was developed in Matlab and comprehensively verified against the latest analytical solutions. The influences of increased ductility in different forms were studied using the modified cohesive zone model in the context of field-scale hydraulic fracturing simulations. Three important conclusions were drawn. First, the shape of TSL does affect the hydraulic fracturing given the same cohesive crack energy and tensile strength. It suggests that ductility is not only controlled by cohesive crack energy and tensile strength, which further indicates the necessity of the newly proposed TSL. Second, the tensile strength, controlling when the cohesive crack starts propagating, has the greatest impact on the hydraulic fracturing, among all TSL shape parameters. The impacts of TSL parameters become less significant as the fracturing fluid viscosity increases. Lastly, Young’s modulus is the only one among four common poroelastic parameters that significantly changes the ductility/brittleness of rock formation and hydraulic fracture lengths. The increase in cohesive energy accompanied by the decrease of Young’s modulus will greatly reduce the induced fracture length.

This presentation demonstrates a CT scanning and image analysis workflow to characterize wellbore cement degradation under corrosive geologic CO2 storage (GCS) conditions. The workflow includes 1) acquisition of raw CT images of the cement sample (before and after exposure to CO2); 2) application of rigid registration to align raw CT images; 3) acquisition of grayscale intensity difference images; 4) application of noise filtering technique to obtain images with good quality; 5) acquisition of 3D pore structure change of the cement sample after CO2 exposure from grayscale intensity difference images, showing degradation of wellbore cement. To demonstrate an application of the workflow, an experiment of reaction between CO2 and wellbore cement under corrosive GCS conditions was conducted and the wellbore cement samples used in the experiment went through aforementioned CT scanning and image analysis procedures. CT image analysis results demonstrate a region with increased porosity in the exterior of the cement sample (Zone 1) and a region with decreased porosity next to Zone 1 due to CaCO3 precipitation (Zone 2). Next to Zone 2, a region with increased porosity due to Ca(OH)2 and C-S-H dissolution (Zone 3) was observed. In summary, this study proves feasibility to use 3D CT scanning and CT image analysis techniques to investigate CO2-induced degradation of wellbore cement.

Improved air quality has been the silver lining of the pandemic since early 2020. The air quality in northern New Jersey was continuously measured during the COVID-19 pandemic and through the three stages of recovery, i.e. the Stay-at-home Stage, Reopening Stage 1 and Reopening Stage 2. A significant change in air quality was observed during the Stay-at-home Stage (March 16 to May 16, 2020) as most people stayed home and industrial activity decreased 60%. Compared to 2019, carbon dioxide (CO2) decreased 17%, carbon monoxide (CO) decreased 7%, and nitrogen oxides (NOx) decreased 51% during the Stay-at-home Stage in 2020. However, the ground-level ozone (O3) increased in 2020 because of the reduced NOx emission and the possibly increased levels of volatile organic compounds (VOCs) due to the warmer weather. With the step-by-step reopening process, the difference in local CO2 levels between 2019 and 2020 was reduced and the NOx concentration returned to its 2019 level. The CO2 concentrations were positively correlated with CO, and the NOx concentrations were negatively correlated with O3 in 2020. However, these correlations are different from those in 2019. The impact of COVID-19 was found to influence the concentration levels of CO2, CO, NOx, and O3 beyond the effects of meteorology parameters on air quality in metropolitan New Jersey. Moreover, our findings provide a reference of air pollution reduction through replacing fossil fuels with electric or renewable energy in the transportation system and industry.

Ambient noise surface wave tomography is an environmentally friendly and cost-effective seismic technique for subsurface imaging. However, noise sources acting from preferential azimuths may introduce bias in the Green’s function reconstruction and in the resultant velocity models. This study, focused at the deposit scale, investigates how to correctly merge the different phase velocity measurements at various frequencies, in order to fill the gap between natural and anthropogenic noise sources while adjusting the bias caused by changes in the azimuth of the source. The target is the Marathon PGE-Cu deposit (Ontario, Canada), an alkaline intrusion containing gabbros and syenites (ø = 25 km). Mineralisation is hosted by gabbros close to the inward-dipping footwall of the intrusion. The country rocks are Archaean volcanic breccias. 1024 vertical-component receivers were deployed for 30 days in two overlapping grids: a 200 m x 6040 m dense array with node spacing of 50 m, and a 4000 m x 2500 m sparse array with node spacing of 150 m. Beamforming analysis of the recorded data indicates variations in the distribution of noise. Below 5 Hz, the Lake Superior (SSW) is the dominant source of noise, while above 12 Hz, noise from the Canadian Pacific Railway and Trans-Canada highway (SW) is prominent. In the 5 - 12 Hz frequency band, surface-wave energy is dominant, and it comes from the Lake Superior and vehicle traffic. Between 12 Hz and 20 Hz, the signal is characterized by body-wave energy combined with less energetic surface waves, while above 20 Hz the imprint of body waves is dominant. We retrieved the fundamental mode of Rayleigh wave propagation from the recorded data set. The signal was down-sampled to 50 Hz, divided into segments of 30 minutes, cross-correlated and stacked. Surface wave dispersion curves were extracted from 2-km-long arrays. Besides, various phase velocity measurements were applied. Phase-velocities were inverted to S-wave velocity structures using different probabilistic approaches. The overall results show a high-velocity shallow anomaly, probably related to the gabbro intrusion hosting the mineralization, as well as other structures consistent with the geological model inferred from surface mapping and drill logs.

This study presents the novel application of tidal gravimetric data in the determination of phase-velocity dispersion curves of Rayleigh surface waves. Tidal gravimeters are capable to detect surface waves of periods even up to 500−600 s, while a typical broad-band seismic sensor can detect them up to the periods of 200−300 s due to its mechanical limitation. The capability of using tidal gravimeters as long period seismometers has already been analyzed since the late ’90s. These researches were mainly focused on the comparison of the power spectral density of noise level of gravimeters and seismometers and the analysis of normal modes of the largest earthquakes recorded by gravimeters. The first steps in the calculation of group velocity dispersion curves of Rayleigh surface waves were carried out lately. The Wiener deconvolution technique was used to calculate the phase-velocity dispersion curve by a two-stations method, from two pre-processed traces recorded in two different stations, located at the same great circle that the epicentre. The Incorporated Research Institutions for Seismology (IRIS) database were searched in terms of availability of at least 1 Hz data recorded by a co-located broad-band seismometer and tidal gravimeter. Additionally, the IRIS database provides the information about the transfer function of instruments, what is necessary in the two-stations method. Only, three sites met the above conditions: Black Forest, Membach and Rochfort, all located in Western and Central Europe. The compatibility of gravimetric and seismic data in the period range of 20-100 s are shown. Tidal gravimeters, because of their higher sensitivity, can better detect weaker earthquakes, which results in a higher number of recordings. However, to explore all advantages of gravimetric recordings of earthquakes, especially up to the periods of 500-600 s, above analysis must be applied to tidal gravimeters with higher inter-station distances and evaluated transfer functions. This work was done in the research project No. 2017/27/B/ST10/01600 financed from the funds of the Polish National Science Centre.

FSO is a symbolic regression method that allows for automatic estimation of the structure and parameterization of transfer functions from catchment data. The FSO method transforms the search for an optimal transfer function into a continuous optimization problem using a text generating neural network (variational autoencoder). mHM is a widely applied distributed hydrological model, which uses transfer functions for all its parameters. For this study, we estimate transfer functions for the parameters saturated hydraulic conductivity and field capacity. To avoid the influence of parameter equifinality, the remaining mHM parameter values are optimized simultaneously. The study domain consists of 229 basins, including 7 major basins for Training and 222 smaller basins for validation, distributed across Germany. 5 years of data are used for training und 35 years for validation. By validating the estimated transfer functions in a set of validation basins in a different time period, we can examine the FSO estimated transfer functions influence on model performance, scalability and transferability. We find that transfer functions estimated by FSO lead to a robust performance when being applied in an ungauged setting. The median KGE of the validation basins in the validation time period is 0.73, while the median KGE of the 7 training basins in training time is 0.8. These results look promising, especially since we are only using 5 years of training data, and show the general applicability of FSO for distributed hydrological models.

The utilization of first-order information about seafloor morphology, derived from multibeam sonar data, has become common in the investigation of deep-sea benthic habitats. When combined with complementary datasets, these data can be used to study deep-sea coral ecosystems and predict environments that are favorable for fish spawning, larval nurseries, and juvenile fish habitats. The identification and protection of these environments is critical where biodiversity is vulnerable or unique in order to rehabilitate or maintain ecological communities and encourage higher fecundity. In August of 2019, the expedition Deep Connections: Exploring Atlantic Canyons and Seamounts was conducted to explore understudied deep-sea environments aboard the NOAA Ship Okeanos Explorer off the coast of the United States and Canada (EX1905L1 and EX1905L2). This expedition included multibeam mapping and seafloor exploration with a Remotely Operated Vehicle (ROV). Observations from ROV dives include several fish species including multiple sightings of Atlantic halibut (Hippoglossus hippoglossus), which is considered endangered on the International Union for Conservation of Nature Red List of Threatened Species. Identifying and classifying the habitats where Atlantic halibut is observed would facilitate future endeavors of protection or rehabilitation. Spawning events are known to coincide with areas of increased seafloor slope associated with high energy systems such as canyons. Utilizing multibeam data included in the Global Multi-Resolution Topography (GMRT) Synthesis, we characterize canyons at the edges of George’s and Brown’s Banks based on morphology, roughness, and seafloor slope and aspect. We combine these data with observations of Atlantic halibut from ROV video to seek correlations that can be used to identify potential habitats. This information can be used to guide further exploration and characterization of the seafloor to better understand the spatial extent of Atlantic halibut habitat in the region.

The longitudinal structure and annual cycle of mean meridional and eddy momentum fluxes in the upper troposphere of the deep tropics are studied using ERA-Interim reanalysis over a 40 year period. In a zonal mean sense, these two terms oppose each other and peak during the Indian summer monsoon. This zonal mean character arises from a rich longitudinal structure revealed by splitting the globe into three zones, namely, the Asia-West Pacific, central Pacific-West Atlantic, and African sectors. The mean meridional convergence term is cohesive across these three regions; it has a single peak in the boreal summer and always acts to decelerate the zonal flow. On the other hand, eddy fluxes are much more varied and go from being small and seasonally invariant in the African sector to having large seasonal peaks of acceleration (deceleration) in the Asia-West Pacific (central Pacific-West Atlantic) sector. This longitudinal variation in eddy momentum fluxes presents interesting insights into the overturning circulation in these zonally limited sectors, which previously remained hidden in the zonal mean.

Extreme precipitation events from the western disturbances have significant impacts on the water management and ecosystem services in the Upper Indus basin, a part of the Hindukush Himalayan region. Further, there are changes in the duration, intensity, spatial extent and frequency of extreme events due to climate change. In this domain, a few studies have assessed the impact of climate change in the study area with limited data. There will be high uncertainty in the outcomes obtained from the investigation of extreme events with limited data. Therefore, a comprehensive analysis of extreme precipitation events from western disturbances considering high resolution with long-term data is required in the study area. Accordingly, In the present study, Precipitation based ETCCDI Indices are calculated for every year, and non-parametric Mann-Kendall test is applied Sen slope is calculated to detect the changes in the monthly precipitation during the winter season for the period 1901-2019. The findings of the present study reveal the northwest region has an increasing trend in RX1day extreme precipitation of 1.85 mm per decade in December, and the rate has amplified due to the effect of western disturbances in January and February. Also, the pattern of RX5day extreme precipitation is consistent in January and February. Overall the wetness in increasing over the north-west part of the study area In recent decades, the northwest region of the upper Indus basin had faced more extreme events with severe impacts due to western disturbances, and outcomes from the study can improve the understanding of extreme events.

The majority of marine plastic pollution originates from land-based sources with the dominant transport agent being riverine. Despite the widespread recognition that rivers dominate the global flux of plastics to the ocean, there is a key knowledge gap regarding the nature of the flux, the behaviour of microplastics (<5mm) in transport and its pathways from rivers into the ocean. To predict transport, fate and biological interactions of microplastics in aquatic environments at a global scale, the factors that control these processes must be identified and understood. Currently, there remains a large knowledge gap around prediction of microplastic transport in rivers, especially in regards to how biofilm formation influence particle settling velocities. This prevents progress in understanding microplastic fate and hotspot formation, as well as curtailing the evolution of effective mitigation and policy measures. A settling experiment was therefore undertaken to understand how different factors, including salinity, suspended sediment concentration and biofilm formation influence microplastic particle settling velocity. The results presented herein explore the role of biofilms on the generation of microplastic flocs and the impact on buoyancy and settling velocities. Five different polymers were tested and compared including fragments and fibres. Settling velocities were then combined with observed flow velocity data from the Mekong River, one of the top global contributors to marine plastic pollution, allowing predictions of areas of microplastic fallout and hotspots. The results highlight potential areas of highest ecological risk related to the dispersal and distribution of microplastics across the river-delta-coast system including the Tonle Sap Lake. Future work involves supporting predicted hotspots with aligned fieldwork from the Mekong River that details the particulate flux and transport of microplastic, throughout the vertical velocity profile.

An improved understanding of the seasonality of the Arctic snowpack properties related to the timing and intensity of snowmelt processes is the key driver to better quantify atmosphere-ice-ocean interactions, and in particular the seasonal energy and mass budgets of the ice-covered polar oceans. Various satellite data products over the last decades have shown a trend towards an earlier snowmelt onset in the Arctic, thus contributing to Arctic amplification and sea-ice decline, underlining the need to better understand these processes. We present here the physical snow properties from spring 2020 examined during the “Multidisciplinary drifting Observatory for the Study of Arctic Climate” (MOSAiC). We focus on southerly air mass advection events in mid-April that were associated with near-surface air temperatures near freezing at the MOSAiC floe. In doing so, we emphasize a single sampling site that was revisited daily-to-weekly throughout the spring. At the sampling site, snow depth ranged from 10 to 14 cm with the bulk density varying between 200 to 350 kg m-3, mainly driven by freshly fallen snow. The vertical snow structure prior to the warm event was characterized by large pores with distinct snow crystal structures and widespread depth hoar crystals, both related to the strong temperature gradient in the snowpack. During the warm air intrusion, increasing temperatures temporarily reversed the thermal gradient in the snow. The warm snow surface, now above a relatively cold snow/ice interface, resulted temporary negative vertical heat flux values observed to be up to -12 Wm-2. Because the snow/ice interface is close to freezing, the negative flux is an indicator that melt may have occurred. Once temperatures dropped again, the vertical temperature and heat flux gradients returned back to the previous patterns. However, the decreased snow grain sizes throughout the snowpack due to the warming and the associated compacted lower layers now dominated the snowpack. Such a temporary warm spell event has decisive impacts on the sea-ice energy and mass budget of the MOSAiC floe. Understanding this effect on a local scale will help to transfer that knowledge to larger spatial scales, and thus to quantify the influence of warm air intrusions during winter and/or spring in the ice-covered Arctic basin.

The University of Houston’s USIP (Undergraduate Student Instrument Project) Remote Sensing team is designing and building an airborne LiDAR with the intention of using it to 3D map landslides and for possible mineral exploration. The maps will be used to conduct landslide analyses and failure predictions while the magnetometer feedback will be used to determine the presence of possible metallic minerals in the area. The LiDAR will employ the use of two lasers with different output wavelengths; 1550nm will be used for typical terrain mapping and 532nm will be used for snow depth reading to extrapolate the underlying terrain characteristics. Trade studies are currently underway for the lasers, sensors, IMU’s and magnetometers. It is planned for the LiDAR to collect data near Fairbanks, Alaska, with further research into potential study sites being conducted. The scan pattern is still being decided on with the most likely option being a circular scan for the 532nm laser and a zig zag pattern for the 1550nm laser both set at a maximum scan angle of 20 degrees. The Remote Sensing team has been facing unforeseen obstacles due to the nature of the COVID-19 pandemic. Upon initial lockdown, weekly scheduled in person meetings and lab work were prohibited. After the first week, though, new mediums of communication were established. The USIP group decided to conduct online meetings through Microsoft Teams and use Slack for text-based communication outside of meetings. Unfortunately, lockdown and COVID chaos brought psychological issues to group members that can be difficult to overcome. This included high stress levels caused by the chaotic events as well as isolation-induced depression. After some deliberation amongst all USIP groups, it was decided to occasionally hold non work-related meetings through Microsoft Teams. This reduced some of the isolation depression by relaxing, talking, and eating pizza. After lockdown restrictions were lifted, the university had begun preventing the previous number of students from being in the lab at once. On top of that, individuals were understandably hesitant to go to the lab, often opting out. Despite this, small groups of USIP students have been going to the labs to clean, disinfect, and get the lab ready for work. New lab procedures have also been created to adhere to social distancing norms.

We investigate the relationship between NO infrared radiation and x-ray radiation at different local time (LT) and latitudes of NO average fluxes. The NO volume emission rates obtained by SABER instrument on board TIMED satellite and x-ray fluxes on long (0.1-0.8 nm) and short (0.05-0.4) channels measured by GOES 12 satellite were used. NO rates were vertically integrated to obtain fluxes, which are then separated into day (8

The India-Asia continental collision, starting at ~50 Ma, has resulted in about 2000 km crustal shortening to build the Himalaya-Tibetan plateau, which is one of the landmark terrestrial features on the Earth. In this study, using a thin viscous sheet approximation we performed scaled laboratory model experiments to investigate the spatiotemporal variation in the Himalaya-Tibetan tectonics. The experiments allow us to constrain the Tibetan plateau topography as a function of the varying India-Asia convergence rates. Our results suggest two rigid crustal blocks: Tarim and Sichuan basins steered the growth pattern in the Tibetan plateau. Because of the resistance from the rigid Tarim block western Tibet uplifted first relative to eastern part, creating a topographic elevation difference, which directed the crustal flows grossly to NE. We show from experiments the elevated plateau topography underwent gravitational collapse when the indentation velocity dropped to present average of ~3.5 cm/yr at around 18 Ma. This event eventually led to a transition from contraction to extensional tectonics, dominated by east-directed crustal flows in response to the eastward topographic gradient developed during the early stage of fast collision. We compare the present day crustal flow velocity field, strain rates, and topographic variations in the model Tibet with the actual observations in the Himalaya-Tibet Mountain System.

Carbonaceous chondrite meteorites are fragments of asteroids or comets, that have remained relatively unaltered since the formation of the Solar System. This extraterrestrial material contains a variety of organic compounds including amino acids, carboxylic acids, and nucleobases, among others. It has been suggested that carbonaceous chondrites may have been essential in the chemical processes that led to the origin of life on Earth (and possibly elsewhere), serving as delivery vehicles of important organic matter during Earth’s early history. Based on the observed relative abundances and the different alteration processes (i.e., thermal metamorphism or aqueous alteration), many synthetic mechanisms have been proposed for the origins of the organic compounds found within carbonaceous chondrites. Among these synthetic routes, there is one mechanism involving the family of aliphatic amides, a class of substrate, with a chemical composition that includes four of the common elements required for life (C, H, O, N) which have been proposed to be important for prebiotic chemistry. The simplest, formamide, has been found in the galactic center, the interstellar medium, and comets. Experimental approaches using formamide with metal oxides, clays, phosphates, or meteorites as catalysts have formed nucleobases, carboxylic acids, amino acids, and amines. Surprisingly, neither formamide nor any other amide have been reported in meteorites. Therefore, we have developed a silylation derivatization method suitable for the identification and quantification of amides in meteoritic samples via gas chromatography mass spectrometry GC-QqQMS. The derivatization protocol was developed using N-methyl-trimethylsilyl trifluoroacetamide (MSTFA) as the silylating agent for the derivatization of eleven C1 to C6 aliphatic amides and urea. Different temperatures, times of derivatization, solvents, volume of solvents, and acid and basic catalysts were evaluated to optimize our protocol. Finally, the optimized method was tested using pyrolyzed Allende meteorite impregnated with the amide standards as a control, and a fragment of Murchison meteorite as an analytical sample. The Allende/standard samples showed no decomposition of the tested compounds nor significant byproduct formation. In the sample of the Murchison meteorite, none of the aliphatic amides could be clearly identified, possibly due to the presence of water in the sample which could have hydrolyzed the amides during extraction or derivatization. Further studies are needed to firmly assess the presence of amides in carbonaceous chondrites either using our silylation protocol with precautions to eliminate water or with a new protocol that is less sensitive to the presence of water.

The Forum for Arctic Modeling and Observational Synthesis (FAMOS) is a project funded by the U.S. National Science Foundation to advance the science of Arctic physical, chemical, and biological marine modeling. It is further designed to foster collaboration with marine observationalists and those who wish to work with Arctic marine modelers, e.g., atmospheric scientists, glaciologists, hydrologists, terrestrial ecologists. FAMOS holds an annual workshop of ~120 people and spawns numerous collaborative projects that have filled three special JGR collections and more. Attendance at FAMOS workshops is a mix of senior researchers and early-career scientists. The final three days of the 4-day workshop consist of AGU-style short talks, break-out sessions, and panel discussions. But the first day is devoted to the FAMOS School, wherein ~ 40 graduate students, postdocs, and early career polar scientists attend 5 longer-format (~ 35 minute) lectures. Discussion sessions are especially highlighted, and senior scientists in attendance are not allowed to speak. A “wild card” after-lunch session is devoted to various topics, e.g., outreach, alternate career choices, and geoengineering. The day ends with a working dinner in which further discussions and networking occur. School attendees are typically gender-balanced and have included students from non-traditional Arctic countries (e.g., Iran, Brazil, Egypt). The FAMOS School has been very successful, as measured by participant feedback and by the number of applications received (i.e., more than we can accommodate each year). A key outcome has been to bolster confidence in the early-career students, so that they are more willing to actively participate in the following days’ activities. This is also enhanced by naming them as session and discussion chairs, and by suppressing the tendency of senior scientists to “hog the microphone.” Discussion at FAMOS workshops has significantly influenced the focus of many PhD projects and spawned a number of student-led research papers. A main lesson learned from the FAMOS School is that just inviting students to a workshop or into a research community is not enough: One must also take active steps to foster confidence and give them a voice. The good news is that this really works.

Ocean Worlds are strong candidates for the first discovery of extraterrestrial life as they may provide liquid water, energy, and biologically essential elements. These bodies are characterized by large volumes of water under a layer of ice, often in contact with a rocky core and powered by tidal heating. Jupiter’s moon Europa is believed to have at least twice as much water as Earth. A key remaining challenge is reaching the oceans of Europa: the thickness of the ice crust may range from 3 km to 30 km. Initial steps have been taken to develop analytical and numerical models of the thermal and physical dynamics of ice penetrators in cryogenic environments, but experimental validation of these models has been limited. We have built and experimentally tested the performance of a set of melt probes in the Europa Tower located at Stone Aerospace. The Europa Tower is a cryogenic vacuum chamber with an internal diameter of 0.75 m and an ice column height of 2 m, capable of maintaining ice at approximately 90 K and surface pressure at near-vacuum (10-3 torr), allowing for the testing of probes designed for the surface of Europa. The Model Validation Probes (MVPs) used are designed to test the fundamental thermal and kinetic properties of melt probes in cryogenic ice. They include monitoring of power, temperature, and penetration depth, with wires stored and released via spools internal to the probe, allowing continued connection after hole closure. MVP1 was tested in January 2020, was powered by a 500 W cartridge heater, and reached a total depth of approximately 1.1 m after about 10 h of test, resulting in an average steady state penetration velocity of roughly 12 cm/h, which is within 10% of theoretical model predictions. This test also confirmed two important aspects of hole initialization: the capability of the probe to start in cryogenic, vacuum conditions where the lack of liquid water limits heat transfer (the “starting problem”), and the rapid melt hole closure following penetration, which allows the probe to continue penetration in a pressurized bubble that contains liquid water. We will also present results of tests with other MVPs, which validate the modeled dependency between the average steady state velocity and the heater power input level. Future work will investigate the effects of ice density and impurities on penetrator performance.