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- Creator:
- Engebretson, Mark J.
- Description:
- Large geomagnetic disturbances (GMDs, also denoted as MPEs - magnetic perturbation events) have sufficient amplitude to cause geomagnetically induced currents (GICs) that can damage technical infrastructure. In this study we present occurrence statistics for GMD / MPE events with derivatives ≥ 6 nT/s and ≥ 20 nT/s from five stations in the MACCS and AUTUMNX magnetometer arrays in Arctic Canada at magnetic latitudes ranging from 65° to 75°. Earlier studies using data from these arrays (Engebretson et al., 2019a,b, 2021a,b) covered only two years (2015 and 2017) and focused on latitude- and local time-dependent occurrence patterns and short-term dependencies on solar wind/IMF parameters and magnetospheric activity indices. This study presents all available data from these stations from 2011 through 2022 to analyze variations of GMD activity over a full solar cycle. Intense GMD activity did not closely follow the sunspot cycle, but instead was lowest during its rising phase and maximum (2011-2014), was highest during the early declining phase (2015-2017), and reached a subsequent minimum early in the following sunspot cycle (2020). GMDs with amplitude >20 nT/s followed the same yearly pattern but peaked even more strongly during 2015-2017. Most of these GMDs were associated with high-speed solar wind streams (Vsw > 600 km/s), but not with strongly negative values of the SYM/H index. The majority of these GMDs, irrespective of the Vsw value, were accompanied within 10 min (and most often less) by other events with amplitude ≥ 6 nT/s and showed a mostly poleward progression. These results show that large amplitude but spatially localized nighttime GMDs are primarily associated with high-speed stream geomagnetic drivers during the declining phase of the solar cycle. This indicates that large GIC hazard conditions can occur for a variety of solar wind drivers and geomagnetic conditions and not only for fast-coronal mass ejection driven storms.
- Keyword:
- geomagnetic disturbance events, geomagnetically induced currents
- Citation to related publication:
- Engebretson, M. J., Steinmetz, Yang, L., Pilipenko, V. A., Moldwin, M. B., McCuen, B. A., Connors, M. G., Weygand, J. M., Waters, C. L., Lyons, L. R., Nishimura, Y., Russell, C. T. (2023) Solar Cycle Dependence of Very Large Nighttime Geomagnetic Disturbances (GMDs) Observed in Eastern Arctic Canada. Journal of Geophysical Research – Space Physics
- Discipline:
- Science
-
- Creator:
- Kort, Eric A., Plant, Genevieve, Brandt, Adam R., Chen, Yuanlei, Fordice, Graham, Gorchov Negron, Alan M., Schwietzke, Stefan, Smith, Mackenzie, and Zavala-Araiza, Daniel
- Description:
- As part of the Flaring & Fossil Fuels: Uncovering Emissions & Losses (F3UEL) project ( https://graham.umich.edu/f3uel), the aircraft measurement platform sampled downwind of flares in the Permian and Eagle Ford regions of Texas (2020) and the Bakken in North Dakota (2021). Estimates of methane destruction removal efficiency are calculated for each airborne intercept of a flare combustion plume based on the observed enhancements of carbon dioxide and methane, along with assumptions about the flare gas composition. Locations provided are the GPS coordinates for the aircraft sampling, not of the upwind flare infrastructure on the ground. Attempts to link the airborne sampling locations to ground infrastructure using the provided wind information (measured at the aircraft), should take care to account for transport in the atmosphere.
- Keyword:
- Natural Gas Flaring, Methane, and Oil & Gas
- Citation to related publication:
- Plant, G., Kort, E. A., Brandt, A. R., Chen, Y., Fordice, G., Gorchov Negron, A. M., Schwietzke, S., Smith, M., & Zavala-Araiza, D. (2022). Inefficient and unlit natural gas flares both emit large quantities of methane. Science, 377(6614), 1566–1571. https://doi.org/10.1126/science.abq0385, Kort, E. A., Plant, G., Smith, M. L., Brandt, A. R., Chen, Y., Gorchov Negron, A. M., Schwietzke, S., Zavala-Araiza, D. (2022). Aircraft Data (2020) for Flaring & Fossil Fuels: Uncovering Emissions & Losses (F3UEL), University of Michigan - Deep Blue Data. https://doi.org/10.7302/1xjm-3v49, and Kort, E. A., Plant, G., Brandt, A. R., Chen, Y., Gorchov Negron, A. M., Schwietzke, S., Smith, M. L., Zavala-Araiza, D. (2022). Aircraft Data (2021) for Flaring & Fossil Fuels: Uncovering Emissions & Losses (F3UEL), University of Michigan - Deep Blue Data. https://doi.org/10.7302/6tgq-e116
- Discipline:
- Science
-
Data for Macroscopic Transition Metal Dichalcogenides Monolayers with Uniformly High Optical Quality
- Creator:
- Li, Qiuyang, Alfrey, Adam, Hu, Jiaqi, Lydick, Nathanial, Paik, Eunice, Liu, Bin, Sun, Haiping, Lu, Yang, Wang, Ruoyu, Forrest, Stephen, and Deng, Hui
- Description:
- This dataset contains raw and source data for all figures generated in the manuscript "Macroscopic Transition Metal Dichalcogenides Monolayers with Uniformly High Optical Quality" The raw data files include '.spe' data, which are spectral data collected by LightField Sofware, and '.dset' and '.vms' files, which are X-ray photoelectron spectroscopy (XPS) data and require CasaXPS to access. The source data files include the processed data that can be directly used for generating the corresponding figures in the manuscript.
- Keyword:
- 2D materials, Exciton-polaritons, and Photonics
- Discipline:
- Science
-
- Creator:
- Walsh, Lisa L
- Description:
- Stable isotope values of carbon (δ13C) and nitrogen (δ15N) from Virginia opossum (Didelphis virginiana) guard hairs were analyzed to evaluate the ecology and winter adaptations in opossums by Dr. Lisa L. Walsh as part of her Ph.D. thesis in the Ecology and Evolutionary Biology Department. The collection of stable isotope data took place from 2017 to 2019. Guard hair was processed at the University of Michigan and analyzed by the University of New Mexico Center for Stable Isotopes (UNM-CSI, USA). Captive and wild opossums were evaluated for evidence of biannual or incomplete biannual molting, a mammalian adaptation to harsh winters. Results suggest opossums do not exhibit either winter molting strategy and that guard hairs capture the opossum’s lifetime diet (Walsh and Tucker 2021). The stable isotope values were used to test the hypothesis that a Type A generalist’s niche is positively correlated with habitat heterogeneity and to evaluate which climate variables best explained isotope values. There was a positive correlation between isotopic niche size and habitat-diversity indexes (Walsh and Tucker 2020). The δ13C values from opossums in the Midwest and Northeast to test whether opossums rely on anthropogenic trash to survive extreme winters. There was no significant relationship between δ13C and winter variables, but there was a significant increase in variance of Midwest opossums’ δ13C after the 1970 corn agricultural boom (Walsh and Tucker 2023).
- Keyword:
- stable isotope, Virginia opossum, mesopredator, ecology, and mammal
- Citation to related publication:
- Walsh, L.L. and P.K. Tucker. 2020. Habitat heterogeneity is correlated with isotopic niche breadth across the range of a mammalian generalist mesopredator. Ecosphere, 11(12): e03314. https://doi.org/10.1002/ecs2.3314, Walsh, L.L. and P.K. Tucker. 2021. Stable isotope values suggest opossums (Didelphis virginiana) at their northern edge do not seasonally molt. Northeastern Naturalist, 28(1): 1-8. https://doi.org/10.1656/045.028.0101, and Walsh, L.L., and P.K. Tucker. 2023. Evaluating anthropogenic influence on a mesopredator: Opossum (Didelphis virginiana) isotope values influenced by corn agriculture more than urbanization. Canadian Journal of Zoology, 101: https://doi.org/10.1139/cjz-2021-0172.
- Discipline:
- Science
-
- Creator:
- Jenkins, G. J. and Bougher, S. W.
- Description:
- In early 2019, the Mars Atmosphere and Volatile Evolution (MAVEN) mission underwent an ~2-month aerobraking campaign, during which time the spacecraft periapsis altitude was lowered from its nominal altitude range of 140-160 km to as low as ~123 km. Excluding spacecraft walk-in/out maneuvers, accelerometer measurements were made along 272 orbits with coverage spanning Ls 340-3°, latitudes ~5-54°S, longitudes 0-360°, and Local Solar Time (LST) ~22-17 hours. In this study, we perform a diagnostic analysis of the full aerobraking data set by fitting 4-harmonic waves to mass densities. We then study the variations of these waves as a function of latitude with an emphasis on those observed previously in Mars’ thermosphere by MAVEN and other missions. Additionally, we utilize data collected during the same time period from the Mars Reconnaissance Orbiter’s Mars Climate Sounder to study the vertical propagation of waves originating from the middle atmosphere. Key results indicate that normalized wave amplitudes decrease with latitude, and this is consistent with the latitudinal structure of a diurnal Kelvin mode. We also observe that waves imprinted from the middle atmosphere show normalized amplitude growth with increasing altitude. A complete summary of data sets, analysis methodology, and scientific results is given. The purpose of this study is to add to the body of knowledge surrounding Martian atmospheric wave features and to provide further constraints for future numerical modeling and subsequent tidal mode identification.
- Keyword:
- MAVEN, Mars Thermosphere, Accelerometer Data Set, Global Data Set, and Wave Analysis of Tides
- Citation to related publication:
- Jenkins, G. A., Bougher, S. W., Lugo, R., Tolson, R. H., Zurek, R. W., Baird, D., Steele, L., Kass, D., Withers, P. (2023), MAVEN Accelerometer Observations of Thermospheric Densities during Aerobraking and Deep Dip 2: Wave Features and Connections to Upward Propagating Thermal Tides, Journal of Geophysical Research: Planets, xx, xx.
- Discipline:
- Science
-
- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:fish:216417 (Acarichthys heckeli (Müller & Troschel, 1849)). Raw Dataset includes 2401 TIF images (each 632 x 853 x 1 voxel at 0.02187606 mm resolution, derived from 2401 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:fish:216417 (Acarichthys heckeli (Müller & Troschel, 1849)). Reconstructed Dataset includes 1972 TIF images (each 632 x 853 x 1 voxel at 0.021876 mm resolution, derived from 2401 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Perciformes, Cichlidae, Acarichthys heckeli (Müller & Troschel, 1849), 1889117016, computed tomography, X-ray, 3D, and DiceCT
- Citation to related publication:
- For more information on the original UMMZ specimen, see: https://www.gbif.org/occurrence/1889117016 and DiceCT for Fishes: Recommendations for pairing iodine contrast agents with μCT to visualize soft tissues in fishes https://doi.org/10.1111/jfb.15320
- Discipline:
- Science
-
- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:fish:252706 (Eigenmannia viricens). Raw Dataset includes 1801 TIF images (each 637 x 456 x 1 voxel at 0.05305043 mm resolution, derived from 1801 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:fish:252706 (Eigenmannia viricens). Reconstructed Dataset includes 1945 TIF images (each 637 x 456 x 1 voxel at 0.053050 mm resolution, derived from 1801 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Actinopterygii, Gymnotiformes, Sternopygidae, Eigenmannia viricens, computed tomography, X-ray, 3D, and DiceCT
- Citation to related publication:
- DiceCT for Fishes: Recommendations for pairing iodine contrast agents with μCT to visualize soft tissues in fishes https://doi.org/10.1111/jfb.15320
- Discipline:
- Science
-
- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:fish:252549 (Bivibranchia bimaculata). Reconstructed Dataset includes 2000 TIF images (each 888 x 988 x 1 voxel at 0.029451 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:fish:252549 (Bivibranchia bimaculata). Raw Dataset includes 1601 TIF images (each 888 x 988 x 1 voxel at 0.02945109 mm resolution, derived from 1601 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Actinopterygii, Characiformes, Hemiodontidae, Bivibranchia bimaculata, computed tomography, X-ray, 3D, and DiceCT
- Citation to related publication:
- DiceCT for Fishes: Recommendations for pairing iodine contrast agents with μCT to visualize soft tissues in fishes https://doi.org/10.1111/jfb.15320
- Discipline:
- Science
-
- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:fish:252559 (Cyphocharax fowleri) - Skull. Reconstructed Dataset includes 1217 TIF images (each 1433 x 1028 x 1 voxel at 0.017592 mm resolution, derived from 1801 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:fish:252559 (Cyphocharax fowleri) - Skull. Raw Dataset includes 1801 TIF images (each 1433 x 1028 x 1 voxel at 0.01759157 mm resolution, derived from 1801 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Actinopterygii, Characiformes, Curimatidae, Cyphocharax fowleri, computed tomography, X-ray, 3D, and DiceCT
- Citation to related publication:
- DiceCT for Fishes: Recommendations for pairing iodine contrast agents with μCT to visualize soft tissues in fishes https://doi.org/10.1111/jfb.15320
- Discipline:
- Science
-
- Creator:
- University of Michigan Museum of Zoology
- Description:
- Scan of specimen ummz:fish:252549 (Bivibranchia bimaculata) - Skull. Reconstructed Dataset includes 1851 TIF images (each 1221 x 1165 x 1 voxel at 0.016589 mm resolution, derived from 2401 scan projections), xtek and vgi files for volume reconstruction. and Scan of specimen ummz:fish:252549 (Bivibranchia bimaculata) - Skull. Raw Dataset includes 2401 TIF images (each 1221 x 1165 x 1 voxel at 0.01658923 mm resolution, derived from 2401 scan projections), xtek and vgi files for volume reconstruction.
- Keyword:
- Animalia, Chordata, Actinopterygii, Characiformes, Hemiodontidae, Bivibranchia bimaculata, computed tomography, X-ray, 3D, and DiceCT
- Citation to related publication:
- DiceCT for Fishes: Recommendations for pairing iodine contrast agents with μCT to visualize soft tissues in fishes https://doi.org/10.1111/jfb.15320
- Discipline:
- Science