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Energy and minerals division tight oil and gas committee: Activities and commodity report for 2019-2020

In 2019, total daily tight oil and gas production increased in the United States month over month, with annualized growth of 14% for oil and 12% for gas. Those gains leveled off in the first quarter of 2020 due to aggressive price competition and increases in international production. Then came the pandemic with a substantially larger dose of economic turmoil, driving down demand due in part to shelter in place orders and safety concerns around travel. Between March and May, tight oil and gas production dropped by nearly 2 million bpd and almost 5 Bcf/day before beginning to recover. Production has continued to increase for the most part through the second half of 2020, but drilling remains subdued throughout most of the U.S. and uncertainty around long term demand along with the current price environment and general state of the economy has contributed to layoffs throughout the industry. Some shale-gas production has declined recently, but a few areas have seen expansion due to construction of LNG facilities along the East Coast of the U.S. (e.g., the Haynesville Formation). Current U.S. shale-gas production is still higher now than in 2019, with daily production of almost 71 Bcf as of October 2020 driven in large part by increased production from the Marcellus Shale in the Appalachian Basin and shales within the Permian Basin. Shale liquids production is down by around a million bpd to approximately 7.1 million (September 2020; U.S. EIA) from pre-pandemic production levels at the end of 2019 and beginning of 2020. Tight oil production remains dominated by plays in the Permian Basin as well as the Bakken and Eagle Ford Formations. On the development and production front, new enhanced oil recovery approaches for tight shale reservoirs are being more widely implemented. Natural gas or CO2 injection is currently being utilized in the Bakken Formation, Eagle Ford Formation, Anadarko Basin, and the Permian Basin to optimize injection sequences and boost recovery. Refracturing of existing wells to reduce drilling costs, improve production, and prolong well productive life has also begun to occur more widely in developed plays. International interest in exploiting hydrocarbons from unconventional reservoirs continues to develop, with active exploration projects on most continents. Europe remains relatively underexplored as compared to North America, although a total of 141 exploration and appraisal wells with a possible shale-gas exploration component have been spudded, including horizontal legs from vertical wells. Shale exploration has made a breakthrough in China with shale gas output in 2019 of 10 billion cubic meters (35.3 Bcf), 60% of which was produced from Sinopec’s Fuling Shale Gas field. Lacustrine shale oil exploration has also been successful in the Sichuan and Ordos Basins in central China, Junggar and Tarim Basins in northwest China, and Songliao Basin in north China, and Bohai Bay Basins in northeast China as of 2018. South America’s potential as an unconventional shale gas and oil province is mainly in Argentina and Brazil, where the production from Neuquen Basin’s tight shale of the Vaca Muerta Formation has been steadily increasing since 2016, but only 4% of the shale resource has been developed thus far. According to International Energy Agency’s report in 2013, Brazil holds the 9th largest unconventional gas reserves. Brazil has shale oil and gas potential in the Parana, Solimoes and Amazon Basins and is actively producing from the oil shale unit of the Irati Formation. In 2019, the Brazil energy ministry launched REATE 2020 to boost onshore investments that include the expectation of drilling an experimental unconventional well in the northeast region. For this inaugural report, the new AAPG EMD Tight Oil and Gas Committee (TO&G; formerly the Shale Gas & Liquids and Tight Gas Sands committees) has developed new commodity report requirements for contributors. This includes shorter annual reports focused on new developments, play concepts, along with the typical updates on production and new drilling in the play areas they cover. We are also asking contributors to collect background geologic and production related information into a document that summarizes important features of the plays they cover that will be stored on the TO&G webpage along with our commodity reports. TO&G is currently working to expand the number of contributors to cover more play areas and replace committee and advisory board members that have recently stepped down. Changes to committee leadership occurred in October as recent chairs transition to EMD elected positions.

Activities and Commodities Report↗

The Wetland and Aquatic Research Center strategic science plan

Introduction The U.S. Geological Survey (USGS) Wetland and Aquatic Research Center (WARC) has two primary locations (Gainesville, Florida, and Lafayette, Louisiana) and field stations throughout the southeastern United States and Caribbean. WARC’s roots are in U.S. Fish and Wildlife Service (USFWS) and National Park Service research units that were brought into the USGS as the Biological Research Division in 1996. Founded in 2015, WARC was created from the merger of two long-standing USGS biology science Centers—the Southeast Ecological Science Center and the National Wetlands Research Center—to bring together expertise in biology, ecology, landscape science, geospatial applications, and decision support in order to address issues nationally and internationally. WARC scientists apply their expertise to a variety of wetland and aquatic research and monitoring issues that require coordinated, integrated efforts to better understand natural environments. By increasing basic understanding of the biology of important species and broader ecological and physiological processes, this research provides information to policymakers and aids managers in their stewardship of natural resources and in regulatory functions. This strategic science plan (SSP) was developed to guide WARC research during the next 5–10 years in support of Department of the Interior (DOI) partnering bureaus such as the USFWS, the National Park Service, and the Bureau of Ocean Energy Management, as well as other Federal, State, and local natural resource management agencies. The SSP demonstrates the alignment of the WARC goals with the USGS mission areas, associated programs, and other DOI initiatives. The SSP is necessary for workforce planning and, as such, will be used as a guide for future needs for personnel. The SSP also will be instrumental in developing internal funding priorities and in promoting WARC’s capabilities to both external cooperators and other groups within the USGS.

Open-File Report↗

Spatial patterns of rainbow smelt energetic condition in Lakes Huron and Erie in 2017: Evidence for Lake Huron resource limitation

Rainbow smelt ( Osmerus mordax ) is a key planktivore and prey fish in Lake Huron. Given the declining offshore productivity in the lake since the early 2000s, we described the energy content of rainbow smelt in 2017 across five different regions (North Channel, Georgian Bay, Saginaw Bay, northern main basin, southern main basin) where phytoplankton and zooplankton productivity likely varied. To increase contrast across the productivity gradient, rainbow smelt energy content was also estimated from western Lake Erie. Within the North Channel where large fish (≥90 mm, total length) were sampled most frequently, mean energy density (kJ/g wet weight) varied seasonally: 4.29 in April (month of spawning), 3.86 in June, 3.99 in July, and up to 4.35 in September. Energy density of rainbow smelt from higher productivity western Lake Erie was 37% (large fish ≥90 mm) to 60% higher (small fish <90 mm) than that of fish from Lake Huron. Within Lake Huron, energy density of rainbow smelt from North Channel was slightly higher than those from other regions; rainbow smelt from Georgian Bay generally had the lowest energy density. Across regions, including western Lake Erie, energy density increased with chlorophyll a concentration. Compared with Lake Huron studies prior to 2004, when oligotrophication had not yet accelerated, energy density of rainbow smelt in 2017 was up to 31% lower. The decline in rainbow smelt energy density is likely the result of declining primary and secondary pelagic production and increased resource limitation for planktivorous fish.

Michigan, Ohio, Ontario↗

Searching for an electrical-grade geothermal resource in Northern Arizona to help geopower the west

The U.S Department of Energy s "Geopowering the West" initiative seeks to double the number of states (currently 4) that generate geothermal electric power over the next few years. Some states, like New Mexico and Oregon, have plentiful and conspicuous geothermal manifestations, and are thus likely to further DOE's goal relatively easily. Other states, including Arizona, demonstrate less geothermal potential, but nevertheless have sites worthy of additional investigation. The Arizona site with greatest potential is near Sunset Crater, a basaltic volcano less than 1,000 years old several kilometers northeast of Flagstaff. Several silicic volcanoes nearby are young enough to have still-hot intrusive roots. Moreover, there is geophysical evidence for magma or hot rock in middle to lower crust beneath the area. A high level of interest in this area by the geothermal industry during the 1970s waned because surface thermal indicators, such as high heat flow, hot springs, and fumaroles are absent. The absence of these features is probably the result of a well-documented deep and pervasive regional aquifer, which likely creates a thermal barrier to the rise of hydrothermal activity from depth, Surface based geological and geophysical studies are under way to evaluate further the geothermal potential of the area and to locate a site for a drill hole to explore for a hydrothermal system beneath the ground-water barrier.

California, Nevada↗

Mapping extent and change in surface mines within the United States for 2001 to 2006

A complete, spatially explicit dataset illustrating the 21st century mining footprint for the conterminous United States does not exist. To address this need, we developed a semi-automated procedure to map the country's mining footprint (30-m pixel) and establish a baseline to monitor changes in mine extent over time. The process uses mine seed points derived from the U.S. Energy Information Administration (EIA), U.S. Geological Survey (USGS) Mineral Resources Data System (MRDS), and USGS National Land Cover Dataset (NLCD) and recodes patches of barren land that meet a &ldquo;distance to seed&rdquo; requirement and a patch area requirement before mapping a pixel as mining. Seed points derived from EIA coal points, an edited MRDS point file, and 1992 NLCD mine points were used in three separate efforts using different distance and patch area parameters for each. The three products were then merged to create a 2001 map of moderate-to-large mines in the United States, which was subsequently manually edited to reduce omission and commission errors. This process was replicated using NLCD 2006 barren pixels as a base layer to create a 2006 mine map and a 2001&ndash;2006 mine change map focusing on areas with surface mine expansion. In 2001, 8,324&thinsp;km 2 of surface mines were mapped. The footprint increased to 9,181&thinsp;km 2 in 2006, representing a 10&middot;3% increase over 5&thinsp;years. These methods exhibit merit as a timely approach to generate wall-to-wall, spatially explicit maps representing the recent extent of a wide range of surface mining activities across the country.

Land Degradation and Development↗

Climate consideration in environmental effects analyses on federal public lands in the United States

Effects of a changing climate, including drought, wildfire, and invasive species encroachment, are evident on public lands across the United States. Decision making on Federal public lands requires analyses under the National Environmental Policy Act (NEPA), and there are guidelines for considering climate in NEPA analyses. To better understand how climate most recently has been considered, we analyzed a stratified random sample of 130 environmental assessments (EAs) completed by the Bureau of Land Management (BLM) from 2021 to 2023 across the contiguous United States. We assessed whether EAs considered (1) potential effects of the proposed action on climate (2) potential climate effects on the proposed action, and (3) potential climate effects on resources of concern. We also identified whether EAs included data and science about climate or greenhouse gas emissions, and which datasets and documents were cited. We used two approaches: automated keyword searches and document analysis. Thirty-seven percent of EAs considered the potential effects of the proposed action on climate, 8% considered the potential effects of climate on the proposed action, and 4% of individual resource analyses considered the potential effects of climate on the resource. EAs in the ‘oil and gas development,’ ‘renewable energy,’ and ‘forestry and timber management’ proposed action categories most frequently considered the potential effects of climate and used climate data and science. Our findings suggest an opportunity for scientists to work more closely with public land managers to identify available data and science for considering climate in environmental effects analyses and to provide science delivery mechanisms that can facilitate the consideration and use of climate science in decision making.

Environmental Management↗

Distribution and foraging patterns of common loons on Lake Michigan with implications for exposure to type E avian botulism

Common loons ( Gavia immer ) staging on the Great Lakes during fall migration are at risk to episodic outbreaks of type E botulism. Information on distribution, foraging patterns, and exposure routes of loons are needed for understanding the physical and ecological factors that contribute to avian botulism outbreaks. Aerial surveys were conducted to document the spatiotemporal distribution of common loons on Lake Michigan during falls 2011–2013. In addition, satellite telemetry and archival geolocator tags were used to determine the distribution and foraging patterns of individual common loons while using Lake Michigan during fall migration. Common loon distribution observed during aerial surveys and movements of individual radiomarked and/or geotagged loons suggest a seasonal pattern of use, with early fall use of Green Bay and northern Lake Michigan followed by a shift in distribution to southern Lake Michigan before moving on to wintering areas. Common loons tended to occupy offshore areas of Lake Michigan and, on average, spent the majority of daylight hours foraging. Dive depths were as deep as 60 m and dive characteristics suggested that loons were primarily foraging on benthic prey. A recent study concluded that round gobies ( Neogobius melanostomus ) are an important prey item of common loons and may be involved in transmission of botulinum neurotoxin type E. Loon distribution coincides with the distribution of dreissenid mussel biomass, an important food resource for round gobies. Our observations support speculation that energy transfer to higher trophic levels via gobies may occur in deep-water habitats, along with transfer of botulinum neurotoxin.

Michigan, Minnesota, Wisconsin↗

Piscivory in recovering Lake Michigan Cisco (Coregonus artedi): The role of invasive species

Contemporary conditions in Lake Michigan where cisco ( Coregonus artedi ) populations are expanding are vastly different from those encountered by the historic fish community. Invasive species introductions have substantially altered the Lake Michigan ecosystem in the last half century. Successful management efforts for cisco in Lake Michigan hinge on our ability to understand their contemporary ecology, especially diet. We collected 725 cisco stomachs opportunistically from commercial fisheries (2%) and in agency surveys (98%) over six years (2014–2019). The majority (70%) of stomachs were from East Grand Traverse Bay and 96% of these were collected at Elk Rapids. Additional samples were collected from Charlevoix (8%), Little Traverse Bay (11%), other sites in northern Lake Michigan (4%), Central Lake Michigan (6%), and Green Bay (1%). Our results indicated a high degree of piscivory, in contrast to historical and contemporary accounts of planktivory for cisco in the other Laurentian Great Lakes. The top three prey items by mass were not native to the Great Lakes and these accounted for 87% of all observed prey mass consumed: round goby ( Neogobius melanostomus) (58%), Bythotrephes longimanus (15%), and alewife ( Alosa pseudoharengus) (14%). Round goby dominated the prey in the spring and summer, while B. longimanus and alewife occurred more in summer and fall diets. The contemporary population of cisco in Lake Michigan has been able to uniquely capitalize on abundant invasive prey resources, which may be less limiting and more energy-rich than a more typical planktivorous cisco diet.

Lake Michigan↗

Mineral deposits of the Mesoproterozoic Midcontinent Rift system in the Lake Superior region – A space and time classification

The Mesoproterozoic Midcontinent Rift System (MRS) of North America hosts a diverse suite of magmatic and hydrothermal mineral deposits in the Lake Superior region where rift rocks are exposed at or near the surface. Historically, hydrothermal deposits, such as Michigan’s native copper deposits and the White Pine sediment-hosted stratiform copper deposit, were major MRS metal producers. On-going exploration for and potential development of copper-nickel sulfide deposits hosted by the Duluth Complex of Minnesota and the opening of the Eagle nickel mine in Michigan indicate an expanding interest in MRS magmatic deposits. MRS hydrothermal and magmatic mineral deposits, many of which are significant past, present, and likely future providers of critical minerals, here are placed into a space and time metallogenic framework. To construct this framework, regional MRS mineral deposits extracted from the U.S. Geological Survey Mineral Resources Data System (MRDS) and the Ontario Ministry of Energy, Northern Development and Mines Mineral Deposit Inventory (MDI) were supplemented by other known and recently recognized mineral deposits described in the literature. All mineral deposits were classified by deposit type, host rock age and type, and estimated timing of mineralization. Deposits were then put into a tectonic evolutionary framework (stages) for the MRS, which shows that deposits formed within discrete spatial and temporal stages of rift evolution.

Lake Superior region↗

Nutrient-reserve dynamics during egg production by female Greater Scaup (Aythya marila): Relationships with timing of reproduction

We studied nutrient-reserve dynamics of female Greater Scaup ( Aythya marila ) to quantify intraspecific strategies of nutrient acquisition for egg production, particularly in relation to the seasonal timing of reproduction (i.e., date of initiation of rapid follicle growth [RFG]). We collected female Greater Scaup on the Yukon-Kuskokwim Delta, Alaska, from arrival through clutch formation during the 2002 and 2003 breeding seasons, and we subsequently conducted standard proximate body-composition analysis. Endogenous lipid, protein, and mineral reserve levels did not decline during egg production. This result differs from most other nutrient-reserve studies of waterfowl, suggesting that female Greater Scaup rely on exogenous food resources, rather than endogenous nutrient reserves, to meet the energy and nutrient costs of clutch formation. Furthermore, endogenous nutrient-reserve levels did not decline with date of RFG initiation, which indicates that body condition at initiation of egg production was similar across the nesting season. We found evidence of nutrient-reserve thresholds for initiation of RFG, in that lipid, protein, and mineral reserves were smaller in nonreproductive than in reproductive females. In light of recent conservation concerns over declining North American scaup populations, our data contrast with nutrient-reserve dynamics described for Lesser Scaup ( A. affinis ).

The Auk↗

Mineral Resources of the Morey and Fandango Wilderness Study Areas, Nye County, Nevada

The Morey (NV-060-191) and Fandango (NV-060-190) Wilderness Study Areas are located in the northern Hot Creek Range about 25 mi north of Warm Springs, Nev. At the request of the Bureau of Land Management, 46,300 acres of the Morey and Fandango Wilderness Study Areas were studied. In this report, the area studied is referred to as 'the wilderness study area', or simply 'the study area'. Geologic, geochemical, geophysical, and mineral surveys were conducted by the USGS and the USBM in 1984 to appraise the identified mineral resources and to assess the mineral resource potential of the study areas. These studies indicate that there are small identified resources of zinc, lead, and silver at the Lead Pipe property in the Fandango Wilderness Study Area, several areas of high potential for the occurrence of gold resources in the Fandango study area, small areas of low and moderate potential for the occurrence of silver, lead, and zinc resources in the Fandango study area, areas of moderate and high potential for the occurrence of silver, lead, and zinc resources in the Morey study area, and an area of low potential for copper, molybdenum, and tin in the Morey study area. Both study areas have low resource potential for petroleum, natural gas, uranium, and geothermal energy.

Bulletin↗

Profiles of gamma-ray and magnetic data from aerial surveys over the conterminous United States

This publication contains images for the conterminous U.S. generated from geophysical data, software for displaying and analyzing the images, and software for displaying and examining the profile data from the aerial surveys flown as part of the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy. The images included are of gamma-ray data (uranium, thorium, and potassium channels), Bouguer gravity data, isostatic residual gravity data, aeromagnetic anomalies, topography, and topography with bathymetry.

conterminous United States↗

Profiles of gamma-ray and magnetic data for aerial surveys over parts of the Western United States from longitude 108 to 126 degrees W. and from latitude 34 to 49 degrees N.

This CD-ROM contains images generated from geophysical data, software for displaying and analyzing the images and software for displaying and examining profile data from aerial surveys flown as part of the National Uranium Resource Evaluation (NURE) Program of the U.S. Department of Energy. The images included are of gamma-ray data (uranium, thorium, and potassium channels), Bouguer gravity data, isostatic residual gravity data, aeromagnetic anomalies, topography, and topography with bathymetry. This publication contains image data for the conterminous United States and profile data for the conterminous United States within the area longitude 108 to 126 degrees W. and latitude 34 to 49 degrees N. The profile data include apparent surface concentrations of potassium, uranium, and thorium, the residual magnetic field, and the height above the ground. The images on this CD-ROM include graytone and color images of each data set, color shaded-relief images of the potential-field and topographic data, and color composite images of the gamma-ray data. The image display and analysis software can register images with geographic and geologic overlays. The profile display software permits the user to view the profiles as well as obtain data listings and export ASCII versions of data for selected flight lines.

Data Series↗

Microplastic particles in dust-on-snow, Upper Colorado River Basin, Colorado Rocky Mountains, 2013–16

Atmospheric dust deposited to snow cover (dust-on-snow) diminishes snow-surface albedo (SSA) to result in early onset and accelerated rate of melting, effects that challenge management of downstream water resources. During ongoing investigations to identify the light-energy absorbing dust particles most responsible for diminished SSA in the Upper Colorado River Basin of the Colorado Rocky Mountains, we found microplastic particles, which are defined as those less than 5 millimeters in any dimension. In each of the 38 samples that represented the last remaining dust layer during melt seasons of 2013–16, microplastics were identified by size, shape, and color, and their relative amounts were visually estimated using stereomicroscopy. Considering the remote, high-elevation settings of the sample sites, the microplastic particles must have been deposited from the atmosphere. The possible role of microplastics for diminishing SSA of snow cover in the Upper Colorado River Basin may be linked to the solar-energy absorptive properties of polymers and is the subject of ongoing investigation.

Colorado↗

Evapotranspiration Rates of Riparian Forests, Platte River, Nebraska, 2002-06

Evapotranspiration (ET) in riparian areas is a poorly understood component of the regional water balance in the Platte River Basin, where competing demands have resulted in water shortages in the ground-water/surface-water system. From April 2002 through March 2006, the U.S. Geological Survey, Nebraska Platte River Cooperative Hydrology Study Group, and Central Platte Natural Resources District conducted a micrometeorological study of water and energy balances at two sites in central Nebraska near Odessa and Gothenburg to improve understanding of ET rates and factors affecting them in Platte River riparian forests. A secondary objective of the study was to constrain estimates of ground-water use by riparian vegetation to satisfy ET consumptive demands, a useful input to regional ground-water flow models. Both study sites are located on large islands within the Platte River characterized by a cottonwood-dominated forest canopy on primarily sandy alluvium. Although both sites are typical of riparian forests along the Platte River in Nebraska, the Odessa understory is dominated by deciduous shrubs, whereas the Gothenburg understory is dominated by eastern redcedars. Additionally, seasonal ground-water levels fluctuated more at Odessa than at Gothenburg. The study period of April 2002 through March 2006 encompassed precipitation conditions ranging from dry to wet. This study characterized the components of the water balance in the riparian zone of each site. ET was evaluated from eddy-covariance sensors installed on towers above the forest canopy at a height of 26.1 meters. Precipitation was measured both above and below the forest canopy. A series of sensors measured soil-moisture availability within the unsaturated zone in two different vertical profiles at each site. Changes in ground-water altitude were evaluated from piezometers. The areal footprint represented in the water balance extended up to 800 meters from each tower. During the study, ET was less variable than precipitation. Annual ET fluctuated about 7 percent from the 4-year mean, ranging from about 514 to 586 millimeters per year (551 on average) at the Odessa site and 535 to 616 millimeters per year (575 on average) at the Gothenburg site. Conversely, annual precipitation fluctuated by about 35 percent from the 4-year mean, ranging from 429 to 844 millimeters per year at Odessa and 359 to 791 millimeters per year at Gothenburg. Of this precipitation, 14 to 15 percent was intercepted by the forest canopy before it could infiltrate into the soil. For the 4-year period, annual ground-water recharge from the riparian measurement zone averaged 76 and 13 millimeters at Odessa and Gothenburg, respectively, to satisfy the water balance at each site. This indicates that, from an annual perspective, ground-water reductions caused by ET may be minimal. This effect varied somewhat and primarily was affected by fluctuations in precipitation. Ground-water discharge occurred during the driest study year (2002), whereas ground-water recharge occurred from 2003 to 2005. These results do not exclude ground water as an important source of water to riparian vegetation - especially to phreatophytes that have the capability of directly using water from the saturated zone - during periods of high ET in the summer, particularly during periods of lower than normal precipitation. However, the calculations indicate that, on an annual (or longer) net-flux basis, ground-water use by riparian forests is likely to be balanced by periods of recharge from excess precipitation at other times of the year. In contrast to more arid settings, where scientific literature indicates that ground water may supply a large fraction of the water used for ET by riparian vegetation, precipitation along the Platte River of Nebraska was great enough - and generally greater than ET - that most or all of the annual ET demand was satisfied by available precipitation. Crop coefficients developed for 15-

Scientific Investigations Report↗

Science to support the understanding of south Texas surface-water and groundwater resources in a changing landscape

Against a backdrop of constant cycles of extreme hydrologic conditions ranging from oppressive droughts to life-threatening floods, the water-resource landscape of south Texas is undergoing constant change. Demands on water resources are increasing because of changes related to population growth, energy demands, agricultural practices, and other human-related activities. In south Texas, the Nueces, San Antonio, and Guadalupe River Basins cover approximately 50,000 square miles and include all or part of 45 counties. These stream systems transect the faulted and fractured carbonate rocks of the Edwards aquifer recharge zone and provide the largest sources of recharge to the aquifer. As the streams make their way to the Gulf of Mexico, they provide water for communities and ecosystems in south Texas and deliver water, sediment, and nutrients to the south Texas bays and estuaries. The U.S. Geological Survey (USGS) works in cooperation with other local, State, and Federal agencies to provide timely access to water data, publications, and information to foster a better understanding of the water resources of south Texas. The USGS and our cooperators are involved in a wide variety of programs for collecting hydrologic data and scientific information in the changing landscape of south Texas to help our cooperators effectively address water-resource issues in this part of the State. This fact sheet provides an overview of our collaborative scientific endeavors in the basins of the Nueces, San Antonio, and Guadalupe Rivers and lower Rio Grande. An overview of USGS capabilities pertaining to water resource issues in Texas, including recently completed and ongoing studies in south Texas, is available at http://tx.usgs.gov/Capabilities/index.html.

Texas↗

Uranium resource assessment in the United States

Uranium is a ubiquitous element-- a little is found in nearly every natural occurring materials, and it is concentrated in many different geologic environments. Thus, uranium differs markedly from the fossil fuels both in its occurrence and how its resources can be assessed. On the one hand uranium behaves like other metals in its occurrences. On the other hand, as a fuel it is like the hydrocarbons in that it is a non-recyclable resources. In addition, uranium occurs in two isotopes that potential may supply energy-- U235 and U238. Present only 0.7% of natural uranium. New technology is being developed to utilize the more abundant isotope U238. Consequently, the U238 obtained from uranium ores that have already been mined and processed (which is now stockpiled) is a resource that may be used in the future.

Conference Paper↗

Improving the operational simplified surface energy balance evapotranspiration model using the forcing and normalizing operation

Actual evapotranspiration modeling is providing useful information for researchers and resource managers in agriculture and water resources around the world. The performance of models depends on the accuracy of forcing inputs and model parameters. We developed an improved approach to the parameterization of the Operational Simplified Surface Energy Balance (SSEBop) model using the Forcing and Normalizing Operation (FANO). SSEBop has two key model parameters that define the model boundary conditions. The FANO algorithm computes the wet-bulb boundary condition using a linear FANO Equation relating surface temperature, surface psychrometric constant, and the Normalized Difference Vegetation Index (NDVI). The FANO parameterization was implemented on two computing platforms using Landsat and gridded meteorological datasets: (1) Google Earth Engine (GEE) and (2) Earth Resources Observation and Science (EROS) Center Science Processing Architecture (ESPA). Evaluation was conducted by comparing modeled actual evapotranspiration ( ETa ) estimates with AmeriFlux eddy covariance (EC) and water balance ETa from level-8 Hydrologic Unit Code sub-basins in the conterminous United States. FANO brought substantial improvements in model accuracy and operational implementation. Compared to the earlier version (v0.1.7), SSEBop FANO (v0.2.6) reduced grassland bias from 47% to −2% while maintaining comparable bias for croplands (11% versus −7%) against EC data. A water balance-based ETa bias evaluation showed an overall improvement from 7% to −1%. Climatology versus annual gridded reference evapotranspiration ( ETr ) produced comparable ETa results, justifying the use of climatology ETr for the global SSEBop Landsat ETa that is accessible through the ESPA website. Besides improvements in model accuracy, SSEBop FANO increases the spatiotemporal coverage of ET modeling due to the elimination of high NDVI requirements for model parameterization. Because of the existence of potential biases from forcing inputs and model parameters, continued evaluation and bias corrections are necessary to improve the absolute magnitude of ETa for localized water budget applications.

Remote Sensing↗