Physical Sciences and Mathematics Commons^™

A Warm-Season Comparison Of Wrf Coupled To The Clm4.0, Noah-Mp, And Bucket Hydrology Land Surface Schemes Over The Central Usa, Matthew S. Van Den Broeke, Andrew Kalin, Jose Abraham Torres Alavez, Robert Oglesby, Q. Steven Hu

Department of Earth and Atmospheric Sciences: Faculty Publications

In climate modeling studies, there is a need to choose a suitable land surface model (LSM) while adhering to available resources. In this study, the viability of three LSM options (Community Land Model version 4.0 [CLM4.0], Noah-MP, and the five-layer thermal diffusion [Bucket] scheme) in the Weather Research and Forecasting model version 3.6 (WRF3.6) was examined for the warm season in a domain centered on the central USA. Model output was compared to Parameter-elevation Relationships on Independent Slopes Model (PRISM) data, a gridded observational dataset including mean monthly temperature and total monthly precipitation. Model output temperature, precipitation, latent heat (LH) …

The Future Of Evapotranspiration: Global Requirements For Ecosystem Functioning, Carbon And Climate Feedbacks, Agricultural Management, And Water Resources, Joshua B. Fisher, Forrest S. Melton, Elizabeth M. Middleton, Christopher Hain, Martha C. Anderson, Richard G. Allen, Matthew Mccabe, Simon Hook, Dennis Baldocchi, Philip A. Townsend, Ayse Kilic, Kevin Tu, Diego Miralles, Johan Perret, Jean-Pierre Lagouarde, Duane Waliser, Adam J. Purdy, Andrew French, David Schimel, James S. Famiglietti, Graeme Stephens, Eric F. Wood

Department of Earth and Atmospheric Sciences: Faculty Publications

The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking …

Tropospheric Emissions: Monitoring Of Pollution (Tempo), P. Zoogman, X. Liu, R. M. Suleiman, W. F. Pennington, D. E. Flittner, J. A. Al-Saadi, B. B. Hinton, D. K. Nicks, M. J. Newchurch, J. L. Carr, S. J. Janz, M. R. Andraschko, A. Arola, B. D. Baker, B. P. Canova, C. Chan Miller, R. C. Cohen, J. E. Davis, M. E. Dussault, D. P. Edwards, J. Fishman, A. Ghulam, G. Gonzalez Abad, M. Grutter, J. R. Herman, J. Houck, D. J. Jacob, J. Joiner, B. J. Kerridge, J. Kim, N. A. Krotkov, L. Lamsal, C. Li, A. Lindfors, R. V. Martin, C. T. Mcelroy, C. Mclinden, V. Natraj, D. O. Neil, C. R. Nowlan, E. J. O'Sullivan, P. I. Palmer, R. B. Pierce, M. R. Pippin, A. Saiz-Lopez, R. J. D. Spurr, J. J. Szykman, O. Torres, J. P. Veefkind, B. Veihelmann, H. Wang, J. Wang

Department of Earth and Atmospheric Sciences: Faculty Publications

TEMPO was selected in 2012 by NASA as the first Earth Venture Instrument, for launch between 2018 and 2021. It will measure atmospheric pollution for greater North America from space using ultraviolet and visible spectroscopy. TEMPO observes from Mexico City, Cuba, and the Bahamas to the Canadian oil sands, and from the Atlantic to the Pacific, hourly and at high spatial resolution (~2.1kmN/S x 4.4 kmE/W at 36.5°N, 100°W). TEMPO provides a tropospheric measurement suite that includes the key elements of tropospheric air pollution chemistry, as well as contributing to carbon cycle knowledge. Measurements are made hourly from geostationary (GEO) …

Intercomparison Of Modis And Viirs Fire Products In Khanty-Mansiysk Russia: Implications For Characterizing Gas Flaring From Space, Ambrish Sharma, Jun Wang, Elizabeth M. Lennartson

Department of Earth and Atmospheric Sciences: Faculty Publications

Gas flaring is commonly used by industrial plants for processing oil and natural gases in the atmosphere, and hence is an important anthropogenic source for various pollutants including CO₂, CO, and aerosols. This study evaluates the feasibility of using satellite data to characterize gas flaring from space by focusing on the Khanty-Mansiysk Autonomous Okrug in Russia, a region that is well known for its dominant gas flaring activities. Multiple satellite-based thermal anomaly data products at night are intercompared and analyzed, including MODIS (Moderate Resolution Imaging Spectroradiometer) Terra level 2 Thermal Anomalies product (MOD14), MODIS Aqua level 2 Thermal …

Evaporation From A Shallow, Saline Lake In The Nebraska Sandhills: Energy Balance Drivers Of Seasonal And Interannual Variability, Diego Andrés Riveros-Iregui, John Lenters, Colin Peake, John T. Ong, Nathan C. Healey, Vitaly A. Zlotnik

Department of Earth and Atmospheric Sciences: Faculty Publications

Despite potential evaporation rates in excess of the local precipitation, dry climates often support saline lakes through groundwater inputs of water and associated solutes. These groundwater-fed lakes are important indicators of environmental change, in part because their shallow water levels and salinity are very sensitive to weather and climatic variability. Some of this sensitivity arises from high rates of open-water evaporation, which is a dominant but poorly quantified process for saline lakes. This study used the Bowen ratio energy budget method to calculate open-water evaporation rates for Alkali Lake, a saline lake in the Nebraska Sandhills region (central United States), …

Evolution Of A Long-Track Violent Tornado Within A Simulated Supercell, Leigh Orf, Robert Wilhelmson, Bruce Lee, Catherine Finley, Adam L. Houston

Department of Earth and Atmospheric Sciences: Faculty Publications

Utilizing state-of-the-art visualization and analysis software, we explore the evolution of a violent tornado within a simulated supercell thunderstorm and describe associated computational challenges.

Interactions Of A Paleocene River, A Rising Fold, And Early-Diagenetic Concretions, David B. Loope, Ross Secord

Department of Earth and Atmospheric Sciences: Faculty Publications

The relative rates of sediment accumulation, erosion, and structural uplift determine whether a growing fold develops positive topographic relief, is beveled by antecedent streams, or is buried under thick growth strata. When folds rise in subsiding basins, upward, convergent flow of groundwater through the permeable growth strata that underlie antecedent streams enhances the flux of ions required for concretion growth. Early diagenetic concretions that grow in such alluvial strata may constitute the only clasts larger than sand size available for transport when antecedent streams become erosive. The first reworked concretions deposited by these streams should accurately mark the transition from …

Rear-Flank Outflow Dynamics And Thermodynamics In The 10 June 2010 Last Chance, Colorado, Supercell, Curtis J. Riganti, Adam L. Houston

Department of Earth and Atmospheric Sciences: Faculty Publications

On 10 June 2010, the second Verification of the Origins of Tornadoes Experiment (VORTEX2) armada observed a supercell thunderstorm near Last Chance, Colorado. Tempest unmanned aircraft system (UAS) data collected in the rear-flank outflow revealed what appeared to be an elevated outflow head, turbulent wake, and a cold rear-flank internal surge (RFIS). Surface thermodynamic and kinematic data collected by the StickNet and mobile mesonet indicated that the outflow wake may have extended to or very near the surface, perhaps modifying or outright replacing the leading edge of the outflow at times. Single-Doppler data collected by the NOAA X-Pol Mobile Polarimetric …

The Possible Role Of Density Current Dynamics In The Generation Of Low-Level Vertical Vorticity In Supercells, Adam L. Houston

Department of Earth and Atmospheric Sciences: Faculty Publications

A physical mechanism based on density current dynamics is proposed to explain the generation of low-level vertical vorticity in supercells. This mechanism may serve as one explanation for the associative relationship between environmental low-level vertical shear and the occurrence of significant tornadoes. The mechanism proposed herein represents an indirect connection to the generation of strong surface-based rotation: the barotropic horizontal vorticity associated with the vertical shear acts to amplify existing rotation but does not directly contribute to surface rotation. The proposed mechanism couples the likelihood of a tornado to the vertical shear through the pattern of vertical motion induced through …

Dynamics Of Cloud-Top Generating Cells In Winter Cyclones. Part Iii: Shear And Convective Organization, Jason M. Keeler, Robert M. Rauber, Brian F. Jewett, Greg M. Mcfarquhar, Roy M. Rasmussen, Lulin Xue, Changhai Liu, Gregory Thompson

Department of Earth and Atmospheric Sciences: Faculty Publications

Cloud-top generating cells (GCs) are a common feature atop stratiform clouds within the comma head of winter cyclones. The dynamics of cloud-top GCs are investigated using very high-resolution idealized WRF Model simulations to examine the role of shear in modulating the structure and intensity of GCs. Simulations were run for the same combinations of radiative forcing and instability as in Part II of this series, but with six different shear profiles ranging from 0 to 10ms21 km21 within the layer encompassing the GCs.

The primary role of shear was to modulate the organization of GCs, which organized as closed convective …

Tornado Warning Response And Perceptions Among Undergraduates In Nebraska, Sabrina T. Jauernic, Matthew S. Van Den Broeke

Department of Earth and Atmospheric Sciences: Faculty Publications

Few studies show how university students perceive and respond to tornado warnings. Lacking in the literature are investigations of what influences perceptions of tornado risk among this population and how these perceptions may influence actions. Through an online survey of 640 undergraduates enrolled at a large university in Nebraska, significant relationships were found between student demographics, perceptions, and response actions. Tornado mythology relevant to the local city influenced perceptions so that students felt the city was less at risk than surrounding rural land. Confirming risk before sheltering remained popular, with some students choosing to never seek shelter during a warning. …

Crustal Distribution In The Central Gulf Of Mexico From An Integrated Geophysical Analysis, Irina Filina

Department of Earth and Atmospheric Sciences: Faculty Publications

This study addresses the question of the crustal composition in the central part of the northern Gulf of Mexico (GOM) – the region of the major disagreement between published tectonic models. The location of the Ocean-Continental Boundary (OCB) for different tectonic models varies within 140 km (87 mi) in the study area. I have developed a 2D model integrating the seismic reflection and refraction data with potential fields (gravity and magnetics) along the profile through the debated region. Two alternative OCB locations were tested. The preferred model suggests the OCB position near the Sigsbee Escarpment, which is in agreement with …

Early Miocene Quantitative Calcareous Nannofossil Biostratigraphy From The Tropical Atlantic, Waheed A. Albasrawi, David K. Watkins

Department of Earth and Atmospheric Sciences: Faculty Publications

A quantitative analysis of calcareous nannofossils was conducted on lower Miocene sediments from Ocean Drilling Program Hole 959A on the West African margin. Combined with data from previous investigations of the lower Miocene from the tropical Atlantic, this research identifies and tests the viability of markers used in current zonation schemes, identifies alternative markers for age boundaries, and examines statistically the most probable order of events in the lower Miocene with the use of the ranking and scaling method (RASC).

Evaluation Of Aerosol Optical Depth And Aerosol Models From Viirs Retrieval Algorithms Over North China Plain, Jun Zhu, Xiangao Xia, Jun Wang, Huizheng Che, Hongbin Chen, Jinqiang Zhang, Xiaoguang Xu, Robert Levy, Min Oo, Robert Holz, Mohammed Ayoub

Department of Earth and Atmospheric Sciences: Faculty Publications

The first Visible Infrared Imaging Radiometer Suite (VIIRS) was launched on Suomi National Polar-orbiting Partnership (S-NPP) satellite in late 2011. Similar to the Moderate resolution Imaging Spectroradiometer (MODIS), VIIRS observes top-of-atmosphere spectral reflectance and is potentially suitable for retrieval of the aerosol optical depth (AOD). The VIIRS Environmental Data Record data (VIIRS_EDR) is produced operationally by NOAA, and is based on the MODIS atmospheric correction algorithm. The “MODIS-like” VIIRS data (VIIRS_ML) are being produced experimentally at NASA, from a version of the “dark-target” algorithm that is applied to MODIS. In this study, the AOD and aerosol model types from these …

Fire And Smoke Remote Sensing And Modeling Uncertainties: Case Studies In Northern Sub‐Saharan Africa, Charles Ichoku, Luke T. Ellison, Yun Yue, Jun Wang, Johannes W. Kaiser

Department of Earth and Atmospheric Sciences: Faculty Publications

Significant uncertainties are incurred in deriving various quantities related to biomass burning from satellite measurements at different scales, and, in general, the coarser the resolution of observation the larger the uncertainty. WRF‐Chem model simulations of smoke over the northern sub‐Saharan African (NSSA) region for January–February 2010, using fire energetics and emissions research version 1.0 (FEERv1) aerosol emissions derived from MODIS measurements of fire radiative power (FRP) and aerosol optical depth (AOD), resulted in a severe model underestimation of AOD compared with satellite retrievals. Such uncertainties are attributable to three major factors: limitations in the spatial and temporal resolutions of the …

Polarimetric Radar Metrics Related To Tornado Life Cycles And Intensity In Supercell Storms, Matthew S. Van Den Broeke

Department of Earth and Atmospheric Sciences: Faculty Publications

Polarimetric radar signatures have been related to the typical evolution of supercell storms, including through tornado life cycles. Now that polarimetric radar observations are available for a large sample of supercell storms, time series of new radar metrics can be derived. These metrics can be compared with phases of known tornado life cycles in an effort to develop new methods of anticipating tornadoes and to increase understanding of storm-scale structural and microphysical changes through supercell and tornado life cycles. In this paper, radar metrics including measures of differential reflectivity Z_DR columns, Z_DR arcs, polarimetrically inferred hailfall regions, and …