Flow of nitrogen into Mississippi Basin believed to cause Gulf hypoxia
No abstract available.
Mississippi Basin↗
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Raster profile development for the spatial data transfer standard
The Spatial Data Transfer Standard (SDTS), recently approved as Federal Information Processing Standard (FIPS) Publication 173, is designed to transfer various types of spatial data. Implementing all of the standard's options at one time is impractical. Profiles, or limited subsets of the SDTS, are the mechanisms by which the standards will be implemented. The development of a raster profile is being coordinated by the U.S. Geological Survey's (USGS) SDTS Task Force. This raster profile is intended to accommodate digital georeferenced image data and regularly spaces, georeferenced gridded data. The USGS's digital elevation models (DEMs) and digital orthophoto quadrangles (DOQs), National Oceanic and Atmospheric Administration's (NOAA) advanced very huh resolution radiometer (AVHRR) and Landsat data, and National Aeronautics and Space Administration's (NASA) Earth observing system (EOS) data are among the candidate data sets for this profile. Other raster profiles, designed to support nongeoreferenced and other types of "raw" sensor data will be consider in the future. As with the Topological Vector Profile (TVP) for the SDTS, development of the raster profile includes designing a prototype profile, testing the prototype profile using sample data sets, and finally, requesting and receiving FIPS approval.
Pecora 12 Symposium↗
Aurora painting pays tribute to Civil War's end
This year marks the sesquicentennial anniversary of the end of the American Civil War, a conflict that Abraham Lincoln called a “mighty scourge.” It was one of the most poignant periods in U.S. history, laying bare political, economic, social, and moral divergence between Northern and Southern states. The cause of the divergence that led to war was slavery [e.g., McPherson , 1988, chap. 3]—an institution that, by the 19th century, had been effectively abolished in the North but remained firmly entrenched in the South. War erupted in 1861 after a confederacy of Southern states declared secession from the Union of the United States. When the war finally ended in 1865, the Union had prevailed, and afterward, slavery was abolished throughout the United States. This outcome was obtained at the cost of 750,000 American lives and substantial destruction, especially in the South [e.g., Gugliotta , 2012]. In 1865, the same year the war ended, the American landscape artist Frederic Edwin Church unveiled Aurora Borealis (pictured above), a dramatic and mysterious painting that can be interpreted in terms of 19th century romanticism, scientific philosophy, and Arctic missions of exploration. Aurora Borealis can also be viewed as a restrained tribute to the end of the Civil War—a moving example of how science and current events served as the muses of late romantic artists [e.g., Carr , 1994, p. 277; Avery , 2011; Harvey , 2012].
Eos, Earth and Space Science News↗
Controls on the stratigraphic architecture of the US Atlantic margin: Processes forming the accommodation space
Accommodation space governs the spatial and temporal distributions of sediments in continental margins. Mapping the sedimentation patterns, therefore, offers insights into the solid-Earth processes that shape accommodation space. We assembled an unprecedented amount of seismic and borehole data along the Eastern North American Margin and used it to divide the margin's sedimentary package into eight chronostratigraphic intervals, identifying temporal shifts in depocenters under the continental shelf, slope, and rise. The Jurassic depocenters follow the syn-rift structure and its thermal subsidence loci. The Long Island Platform is the only margin segment where the early post-rift sediment thickness matches subsidence predictions from uniform-stretching models, whereas in Georges Bank Basin (GBB) and Baltimore Canyon Trough (BCT), sediment thickness is 1.5–3 times higher than predicted, pointing to other factors at play. A margin-wide Jurassic transient shoulder uplift is inferred from the occurrence of stratigraphic onlaps above thinned crust. Unlike the Jurassic, the Cretaceous and Cenozoic depocenters disregard the inherited subsidence pattern. The accommodation space over the shelf and coastal plain during the Cretaceous was affected by regional isostatic compensation of the sedimentary loads accumulated on the shelf and rise. Accommodation space development in the GBB was interrupted during the Cretaceous after the margin crossed the Great Meteor Hotspot track, resulting in a widespread permanent uplift, erosion, and sediment redistribution. The distribution of anomalous Neogene subsidence in the BCT challenges previous suggestions of mantle dynamic control on the accommodation space and favors flexural downwarping of the shelf by sediment accumulation on the rise.
Journal of Geophysical Research: Solid Earth↗
Estimation of elastic moduli in a compressible Gibson half-space by inverting Rayleigh-wave phase velocity
A Gibson half-space model (a non-layered Earth model) has the shear modulus varying linearly with depth in an inhomogeneous elastic half-space. In a half-space of sedimentary granular soil under a geostatic state of initial stress, the density and the Poisson's ratio do not vary considerably with depth. In such an Earth body, the dynamic shear modulus is the parameter that mainly affects the dispersion of propagating waves. We have estimated shear-wave velocities in the compressible Gibson half-space by inverting Rayleigh-wave phase velocities. An analytical dispersion law of Rayleigh-type waves in a compressible Gibson half-space is given in an algebraic form, which makes our inversion process extremely simple and fast. The convergence of the weighted damping solution is guaranteed through selection of the damping factor using the Levenberg-Marquardt method. Calculation efficiency is achieved by reconstructing a weighted damping solution using singular value decomposition techniques. The main advantage of this algorithm is that only three parameters define the compressible Gibson half-space model. Theoretically, to determine the model by the inversion, only three Rayleigh-wave phase velocities at different frequencies are required. This is useful in practice where Rayleigh-wave energy is only developed in a limited frequency range or at certain frequencies as data acquired at manmade structures such as dams and levees. Two real examples are presented and verified by borehole S-wave velocity measurements. The results of these real examples are also compared with the results of the layered-Earth model. ?? Springer 2006.
Surveys in Geophysics↗
Landsat: A Global Land-Imaging Project
Across nearly four decades since 1972, Landsat satellites continuously have acquired space-based images of the Earth's land surface, coastal shallows, and coral reefs. The Landsat Program, a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), was established to routinely gather land imagery from space; consequently, NASA develops remote-sensing instruments and spacecraft, then launches and validates the satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground-data reception, archiving, product generation, and distribution. The result of this program is a visible, long-term record of natural and human-induced changes on the global landscape.
Fact Sheet↗
Landsat: A global land-imaging mission
Across four decades since 1972, Landsat satellites have continuously acquired space-based images of the Earth's land surface, coastal shallows, and coral reefs. The Landsat Program, a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), was established to routinely gather land imagery from space. NASA develops remote-sensing instruments and spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and distribution. The result of this program is a long-term record of natural and human induced changes on the global landscape.
Fact Sheet↗
Landsat Science Team: 2017 Winter meeting summary
The winter meeting of the NASA-U.S. Geological Survey (USGS) Landsat Science Team (LST) was held January 10-12, 2017, at Boston University. LST co-chairs Tom Loveland [USGS’s Earth Resources Observation and Science Center (EROS)—Senior Scientist], Jim Irons [NASA’s Goddard Space Flight Center (GSFC)—Deputy Director, Earth Sciences Division], and Curtis Woodcock [Boston University—Professor and LST Co-Leader] welcomed the participants to the three-day meeting. The group immediately and enthusiastically recognized Woodcock’s receipt of the 2016 Pecora Award. Loveland summarized the primary meeting objectives to identify priorities for future Landsat measurements and to begin identifying next-generation Landsat products. He also discussed USGS’s plans to issue a request for proposals for membership on the 2018-2023 LST (i.e., the next five-year term). Irons stressed Landsat’s bipartisan support but cautioned against complacency when looking toward future capabilities. Meeting presentations are available at https://landsat.usgs.gov/landsat-science-teammeeting-jan-10-12-2017.
The Earth Observer↗
Landsat: a global land imaging program
Landsat satellites have continuously acquired space-based images of the Earth's land surface, coastal shallows, and coral reefs across four decades. The Landsat Program, a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), was established to routinely gather land imagery from space. In practice, NASA develops remote-sensing instruments and spacecraft, launches satellites, and validates their performance. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground-data reception, archiving, product generation, and distribution. The result of this program is a visible, long-term record of natural and human-induced changes on the global landscape.
Fact Sheet↗
Landsat 1-5 Multispectral Scanner System (MSS) sensors radiometric calibration update
First launched in 1972, the Landsat satellite sensors have provided the longest continuous record of high quality images of the Earth’s surface that are used in both civilian and military applications. The Landsat Multispectral Scanner (MSS) sensor was on-board Landsat-1 through Landsat-5. In fact, the MSS sensors provide the only systematic global multispectral space-based imagery of the Earth’s surface from 1972 to 1982. This paper focuses on the radiometric calibration update of the Landsat 1-5 MSS sensors. The radiometric calibration was performed in both radiance and reflectance-based scales through cross-calibration approach. Simultaneous or a near simultaneous image collections were available for MSS sensor pairs and used for the cross-calibration. The estimated uncertainties for this calibration update exhibit progressively decreasing calibration accuracy, ranging from 5.1% for MSS 5 to 8.8% for MSS-1 in the Green spectral band, for example. Lastly, the new radiometric calibration coefficients were validated through the use of pseudo invariant calibration sites (PICS). The temporal TOA Radiance and TOA Reflectance over the Sonoran Desert were plotted with the purpose of verifying the lifetime radiometric stability of MSS sensors. With the previous calibration, the agreement between the measurements of TOA Reflectance over the Sonoran Desert was around 7.5% for all spectral bands. With the calibration update implemented in this study, the agreement between MSS sensors is 3.6%, 2.9%, 3.5% and 5.9% for the Green, Red, NIR-1 and NIR 2 spectral bands, respectively. This study ties all the Landsat legacy instruments from Landsat-1 MSS through Landsat-8 OLI to a consistent radiometric scale.
IEEE Transactions on Geoscience and Remote Sensing↗
Radiometric calibration of the Landsat MSS sensor series
Multispectral remote sensing of the Earth using Landsat sensors was ushered on July 23, 1972, with the launch of Landsat-1. Following that success, four more Landsat satellites were launched, and each of these carried the Multispectral Scanner System (MSS). These five sensors provided the only consistent multispectral space-based imagery of the Earth's surface from 1972 to 1982. This work focuses on developing both a consistent and absolute radiometric calibration of this sensor system. Cross-calibration of the MSS was performed through the use of pseudoinvariant calibration sites (PICSs). Since these sites have been shown to be stable for long periods of time, changes in MSS observations of these sites were attributed to changes in the sensors themselves. In addition, simultaneous data collections were available for some MSS sensor pairs, and these were also used for cross-calibration. Results indicated substantial differences existed between instruments, up to 16%, and these were reduced to 5% or less across all MSS sensors and bands. Lastly, this paper takes the calibration through the final step and places the MSS sensors on an absolute radiometric scale. The methodology used to achieve this was based on simultaneous data collections by the Landsat-5 MSS and Thematic Mapper (TM) instruments. Through analysis of image data from a PICS location and through compensating for the spectral differences between the two instruments, the Landsat-5 MSS sensor was placed on an absolute radiometric scale based on the Landsat-5 TM sensor. Uncertainties associated with this calibration are considered to be less than 5%.
IEEE Transactions on Geoscience and Remote Sensing↗
Effect of crustal layering upon dislocation modeling
Slip distribution at depth on a fault may be inferred from the deformation observed on the surface. In inverting the surface deformation data to obtain the slip distribution, the Earth is generally approximated by an elastic half‐space. Slip distributions inferred from a half‐space model may contain artifacts, including zones of reversed slip, due solely to effects of layering in the real Earth. This effect is demonstrated for a vertical strike‐slip fault in an Earth consisting of an elastic layer overlying an elastic half‐space. Slip on the fault is taken to be independent of the along‐strike coordinate (i.e., antiplane strain is assumed). For a given slip distribution in this model the slip distribution on a similar fault in an elastic half‐space is found that produces the identical surface deformation. Comparison of the two slip distributions reveals structure introduced into the half‐space equivalent slip profile by crustal layering. The comparisons suggest that low‐resolution inversion schemes (e.g., single screw dislocation models) are not drastically affected by Earth structure, but attempts at detailed inversion are likely to produce profiles contaminated by artifacts of Earth structure.
Journal of Geophysical Research B: Solid Earth↗
The USGS geomagnetism program and its role in space weather monitoring
Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring.
Space Weather↗
The anatomy and lethality of the Siberian Traps large igneous province
Emplacement of the Siberian Traps large igneous province (LIP) around 252 Ma coincided with the most profound environmental disruption of the past 500 million years. The enormous volume of the Siberian Traps, its ability to generate greenhouse gases and other volatiles, and a temporal coincidence with extinction all suggest a causal link. Patterns of marine and terrestrial extinction/recovery are consistent with environmental stresses potentially triggered by the Siberian Traps. However, the nature of causal links between the LIP and mass extinction remains enigmatic. Understanding the origins, anatomy, and forcing potential of the Siberian Traps LIP and the spatiotemporal patterns of resulting stresses represents a critical counterpart to high-resolution fossil and proxy records of Permian–Triassic environmental and biotic shifts. This review provides a summary of recent advances and key questions regarding the Siberian Traps in an effort to illuminate what combination of factors made the Siberian Traps a uniquely deadly LIP. Large igneous provinces such as the Siberian Traps are capable of triggering global environmental destabilization. Greenhouse gases generated by Siberian Traps magmatism played a major role in driving the climate changes that triggered the end-Permian mass extinction. The end-Permian extinction fundamentally altered the evolutionary trajectory of Earth's biosphere, creating ecological space for many of the organisms seen today. Determining the timing and patterns of end-Permian marine and terrestrial mortality and recovery and the timing and character of Siberian Traps magmatism is key in understanding the causal link between magmatism and extinction. Understanding the cause(s) of past extinction events informs hypotheses about current and future environmental destabilization.
Siberia↗
System characterization report on the BlackSky Global multispectral sensor
Executive Summary This report addresses system characterization of the BlackSky Global satellites and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the specific sensing system being evaluated; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. The BlackSky Global satellites are three-band multispectral imagers (red, green, and blue multispectral bands plus a panchromatic band) with a 0.8- to 0.9-meter (m) pixel ground sample distance for the assessed satellites. BlackSky Global satellites 9 and 12–17 were launched in March and December 2021, respectively, into a Sun-synchronous orbit of 430–450 kilometers with an inclination of 42–53 degrees and a swath width of 6 kilometers at nadir. Each Global satellite has an expected lifetime of about 3 years. More information on the BlackSky Global satellites is available in the “Land Remote Sensing Satellites Online Compendium” ( https://calval.cr.usgs.gov/apps/compendium ) and from BlackSky at Real-Time Space-Based Intelligence (blacksky.com) The Earth Resources Observation and Science Cal/Val Center of Excellence system characterization team completed data analyses to characterize the geometric (interior and exterior) and spatial performances. Results of these analyses indicate that the assessed BlackSky Global satellites have an interior geometric performance in the range of −0.011 m (−0.012 pixel) to 0.007 m (0.008 pixel) in easting and −0.018 m (−0.020 pixel) to 0.012 m (0.013 pixel) in northing in band-to-band registration; an exterior geometric performance using ground control points of 8.0-m circular error (95-percent certainty) for orthorectified products and 10.7- to 17.4-m circular error (95-percent certainty) for nonorthorectified products, depending on the geolocation metadata used; and a spatial performance in the range of 1.70 to 2.43 pixels for full width at half maximum, with a modulation transfer function at a Nyquist frequency in the range of 0.032 to 0.084.
Open-File Report↗
Unlocking ecological insights from sub-seasonal visible-to-shortwave infrared imaging spectroscopy: The SHIFT campaign
We stand at the threshold of a transformative era in Earth observation, marked by space-borne visible-to-shortwave infrared (VSWIR) imaging spectrometers that promise consistent global observations of ecosystem function, phenology, and inter- and intra-annual change. However, the full value of repeat spectroscopy, the information embedded within different temporal scales, and the reliability of existing algorithms across diverse ecosystem types and vegetation phenophases have remained elusive due to the absence of suitable sub-seasonal spectroscopy data. In response, the Surface Biology and Geology (SBG) High-Frequency Time Series (SHIFT) campaign was initiated during late February 2022 in Santa Barbara County, California. SHIFT, designed to support NASA's SBG mission, addressed mission scoping, scientific advancement, applications development, and community building. This ambitious endeavor included weekly Airborne Visible InfraRed Imaging Spectrometer-Next Generation (AVIRIS-NG) imagery acquisitions for 13 weeks (spanning February 24 to May 29, 2022), accompanied by coordinated terrestrial vegetation and coastal aquatic data collection. We describe the rich datasets collected and illustrate how the complex sub-seasonal patterns of change can be linked to biological science and applications, surpassing insights from multispectral observations. Leveraging open-source processing methods and cloud-based analysis tools, the SHIFT campaign showcases the readiness of the scientific community to harness ecological insights from remotely sensed hyperspectral time series. We provide an overview of SHIFT's goals, data collections, preliminary results, and the collaborative efforts of early career scientists committed to unlocking the transformative potential of high-frequency time series data from space-borne VSWIR imaging spectrometers.
Ecosphere↗
Progress in remote sensing as it applies to missions of Committee for Coordination of Joint Prospecting for Mineral Resources in Asian Offshore Areas
The major thrusts of investigations of the use of space data for understanding our Earth continue to focus on the land and near-shore environments. This is expectable; people live on the land, draw most of their resources from the land or near-shore areas, and in these areas environmental degradation or improvement are most clearly observable. An exception to this focus of investigation was the launch of Seasat, a satellite dedicated to marine investigations. Seasat was short lived but the data produced strongly supported the use of imaging radar for land investigation, and, although studies are incomplete, suggest eventual benefits for the navigator, searchers for marine resources, and mariners--provided that the data and/or interpretations can be available to the marine users shortly after collection. In this regard, the positive steps now being taken in Southeast Asia to establish reception, processing, and interpretation centers are a major development.
Open-File Report↗
Hydrogeology of Picacho Basin, south-central Arizona
The hydrogeology of Picacho Basin was studied to define the stratigraphy, basin structure, physical and hydraulic properties of the basin sediments, and predevelopment and postdevelopment conditions of ground-water flow as of 1985. The study area includes about 900 square miles and contains a sedimentfilled asymmetric graben. The greatest sediment thickness occurs along the east margin of the graben. Basin sediments contain the principal water-bearing units and are separated into lower, middle, and upper units. The lower unit is several thousand feet thick and contains a conglomerate facies and a playa facies that contains a thick evaporite sequence. The middle and upper units contain alluvial and playa facies that are as much as 1,500 feet thick. Ground water occurs in lower and upper aquifer systems separated by a middle confining unit that comprises the playa facies of the three units. Hydraulic properties and compressibility of the middle and upper units are much greater than those of the lower unit. Vertical-head gradients exist, and vertical flow occurs within and between the aquifer systems. Early development of surface-water supplies resulted in increased recharge through deep percolation of irrigation water. Later development of the ground-water supplies resulted in extensive water-level declines, changes in the direction of ground-water flow, removal of water from storage, aquifer compaction, land subsidence, and earth fissures. Dewatering of pore spaces in the upper unit has been the primary source of water; however, as much as 80 percent of the water derived from storage in the Eloy area has resulted from compaction of pore spaces.
Arizona↗