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USGS2011

Using remote sensing and imagery exploitation to monitor the dynamics of East Timbalier Island, LA: 2000-2010

In 1999, the National Oceanic and Atmospheric Administration-National Marine Fisheries Service and the State of Louisiana jointly undertook the restoration of East Timbalier, a barrier island along a sediment-starved portion of the Gulf of Mexico coast of Louisiana. High-resolution overhead imagery was used to monitor the course of this restoration effort. This article describes the changes in area and movement of East Timbalier Island and compares these changes with the previous measurements. Between 2000 and 2010, East Timbalier Island lost 52–66% of its area and moved northwards 12–105 m/year. The area of East Timbalier Island is less today than at any time since 1887. Understanding of the physical processes in nature that control the size, shape and movement of the island, as well as the human impacts that have hastened its degradation, is critical for accomplishing any future restoration.

Louisiana↗

USGS2021

Development of soil radiocarbon profiles in a reactive transport framework

Today, there is a greater appreciation for the importance of the physical protection of carbon (C) through interactions with mineral surfaces, isolation from microbes, and the important role of transport in shaping soil properties and controlling moisture limitations on decomposition. As our paradigm for soil organic carbon (SOC) preservation changes, so too should our representation of the underlying processes in soil models. Reactive transport models (RTMs) provide a framework capable of assessing the interactive influence of soil chemistry and transport processes on the accumulation and turnover of SOC. In this study, we present new developments in the isotopically enabled RTM “CrunchTope,” which is capable of explicitly tracking the three isotopes of carbon ( 12 C, 13 C, and 14 C) and their fractionation between multiple coexisting and interacting solid, liquid and gas phases. This modeling framework opens the door to new applications of depth-resolved RTMs models in application to SOC and deeper subsurface carbon reservoirs. Here, we demonstrate SOC accumulation and radiocarbon aging for long-timescale models of soil development in CrunchTope. Our goal is to assess advantages and limitations of such an approach and to identify the type and complexity of reaction networks that are required to adequately apply this model to SOC dynamics. We assess the behavior of this model relative to a high-resolution dataset of SOC content, stable isotope composition, and radiocarbon ages as well as physical and hydrologic data measured from a chronosequence of soils located near Santa Cruz, California. Starting from a previously published model using a simplified reaction network with a single class of carbon, we sequentially incorporate multiple C reservoirs subject to both reactivity and transport pathways. Our results indicate that multiple SOC pools with different mean ages of C do not inherently emerge as a result of including reactions which are conventionally expected to provide a diversity of transit times, i.e., sorption and complexation of SOC on mineral surfaces. Instead, transit times emerge as a result of the timescales of the reactions represented in the reaction network. For mineral associated C, the RTM framework imposes dynamic equilibrium with the fluid phase dissolved organic C, such that no distinction in radiocarbon ages is achieved between these pools. Aged C can be produced by including a solid-phase C reservoir, with a rate-limited solubilization coefficient. Aging of SOC in this way is more akin to selective preservation than to mineral protection and, while such a mechanism may be at play in many soils, mineral protection is thought to be at least as important. As such, our results indicate that additional parameterization is required to reproduce the heterogeneity of carbon transit times that result from organo-mineral interactions. These efforts show the promise of a modeling approach where the varied transit time of soil C emerges from the dynamic physical and hydrologic properties of the model rather than from the a priori assignment of operationally defined pools.

Geochimica et Cosmochimica Acta↗

USGS1999

Commemorative naming in the United States

Naming is a basic human tendency; it allows us to perceive the distinct identities of people and places and conveys those characteristics that make them unique. The name of a geographic feature can describe spectacular physical attributes (such as the Grand Canyon or Half Dome in Yosemite National Park), indicate cultural or historical significance (such as Washington Crossing on the Delaware River), or commemorate a worthy individual (such as the Hudson River, named for Henry Hudson, the explorer). Names have many different origins, and regardless of the type of name, they give us a greater familiarity with our surroundings and a sense of belonging to our environment. Naming rivers, mountains, and valleys after individuals was one way settlers marked the land; it signified their lives on these lands were important and, in addition to being a point of reference, usually satisfied the need for stability and enhanced the general concept of sense of place. Even today, naming geographic features after individuals helps us to recognize their special achievements and contributions to the physical or cultural landscape. However, what may be most significant about the present commemorative naming decisions is their permanence. It is important for us to realize that the commemorative names assigned today may last for centuries.

Fact Sheet↗

USGS1998

Commemorative Naming in the United States

Fact Sheet↗

USGS2021

Dry formation of recent Martian slope features

Martian surface conditions are cold and dry, unfavorable for liquid water, yet steep slopes display young and currently active features suggestive of wet processes. These include recurring slope lineae and slope streaks, gully landforms, and small lobate features. Wet origins for these features would imply surprising amounts of liquid water at the surface. However, detailed observations of the morphology and activity of these features have demonstrated that dry processes, some of them unique to the Martian environment, can account for all of them. This reconciles the contradiction between physics and geomorphology and provides a self-consistent model of a Martian surface that is very active today despite having negligible volumes of liquid water.

Book chapter↗

USGS2017

Niobium and tantalum

Niobium and tantalum are transition metals that are almost always found together in nature because they have very similar physical and chemical properties. Their properties of hardness, conductivity, and resistance to corrosion largely determine their primary uses today. The leading use of niobium (about 75 percent) is in the production of high-strength steel alloys used in pipelines, transportation infrastructure, and structural applications. Electronic capacitors are the leading use of tantalum for high-end applications, including cell phones, computer hard drives, and such implantable medical devices as pacemakers. Niobium and tantalum are considered critical and strategic metals based on the potential risks to their supply (because current production is restricted to only a few countries) and the significant effects that a restriction in supply would have on the defense, energy, high-tech industrial, and medical sectors. The average abundance of niobium and tantalum in bulk continental crust is relatively low—8.0 parts per million (ppm) niobium and 0.7 ppm tantalum. Their chemical characteristics, such as small ionic size and high electronic field strength, significantly reduce the potential for these elements to substitute for more common elements in rock-forming minerals and make niobium and tantalum essentially immobile in most aqueous solutions. Niobium and tantalum do not occur naturally as pure metals but are concentrated in a variety of relatively rare oxide and hydroxide minerals, as well as in a few rare silicate minerals. Niobium is primarily derived from the complex oxide minerals of the pyrochlore group ((Na,Ca,Ce) 2 (Nb,Ti,Ta) 2 (O,OH,F) 7 ), which are found in some alkaline granite-syenite complexes (that is, igneous rocks containing sodium- or potassium-rich minerals and little or no quartz) and carbonatites (that is, igneous rocks that are more than 50 percent composed of primary carbonate minerals, by volume). Tantalum is derived mostly from the mineral tantalite ((Fe,Mn)(Ta,Nb) 2 O 6 ), which is found as an accessory mineral in rare-metal granites and pegmatites that are also enriched in lithium and cesium (termed lithium-cesium-tantalum (LCT)-type pegmatites). Brazil and Canada are the leading nations that produce niobium mineral concentrates, but Brazil is by far the leading producer, accounting for about 90 percent of production, which comes mostly from weathered material derived from carbonatites. Brazil and Canada also have the largest identified niobium resources; additional resources, although they are less well reported, occur in Angola, Australia, China, Greenland, Malawi, Russia, and South Africa. Australia and Brazil have been the leading producers of tantalum mineral concentrates, although recently Ethiopia and Mozambique have also been significant suppliers of tantalum. Artisanal mining of columbite-tantalite (also called coltan) is practiced in many countries, particularly Burundi, the Democratic Republic of the Congo (Congo [Kinshasa]), Nigeria, Rwanda, and Uganda. Brazil has about 40 percent of the identified tantalum resources; other countries and regions with identified tantalum resources include, in decreasing order of resources, Australia, Asia, Russia and the Middle East, Africa, North America, and Europe. Identified niobium and tantalum resources in the United States are small, low grade, and difficult to recover and process, and are thus not commercially recoverable at current prices. Consequently, the United States meets its current and expected future needs for niobium and tantalum through imports of primary mineral concentrates and alloys and through recovery from foreign and domestic alloy scrap that contain the metals. Environmentally, the main issues related to niobium and tantalum mining are land disruptions, the volume of waste materials and their disposal, and the radioactivity of some tailings and waste materials that contain thorium and uranium. Because of the relative biological inertness of niobium and tantalum, human and ecological health concerns are generally minimal under most natural conditions. Demand for both niobium and tantalum is expected to increase as the world economy continues to recover from the downturn that began in 2008. Increased demand for niobium is linked to increased consumption of microalloyed steel, which is used in the manufacture of cars, buildings, ships, and refinery equipment. Demand for these steels will likely increase with continued economic development in such countries as Brazil, China, and India. In addition, increased global demand for cars, cell phones, computers, superconducting magnets, and other high-tech devices will likely spur increased demand for both niobium and tantalum. The estimated global reserves and resources of niobium and tantalum are large and appear more than sufficient to meet global demand for the foreseeable future, possibly the next 500 years. The sale of “conflict coltan” attributed to rebel forces waging a civil war in Congo (Kinshasa) has been of recent concern and has highlighted the need for a transparent and traceable global supply chain that can exclude illegal columbite-tantalite from the conventional market while discerning legitimate artisanal mine production in central Africa.

Professional Paper↗

USGS2016

Sediment budgets, transport, and depositional trends in a large tidal delta

The Sacramento-San Joaquin Delta is the largest delta on the west coast of the United States. It is formed where the confluence of California’s two largest rivers (the Sacramento and San Joaquin) meet the ocean tides and has a significant physical gradient from fluvial to tidal. It is a semidiurnal system (two high and two low tides per day). Today, the Delta is one of the most manipulated in the United States. Once composed of many shallow, meandering and braided dendritic channels and dead-end sloughs and wetlands, it is now a network of leveed canals moving clear water around subsided islands. It historically has supported a biologically diverse tidal wetland complex, of which only 3% remains today (Whipple et al., 2012). It has also witnessed a collapse in the native fish populations. The Delta provides critical habitat for native species, however the hydrology and water quality are complicated by manipulations and diversions to satisfy multiple statewide objectives. Today water managers face co-equal goals of water supply to Californians and maintenance of ecosystem health and function. The Delta is a hub for both a multi-hundred-million dollar agricultural industry and a massive north-to-south water delivery system, supplying the primary source of freshwater to Central Valley farmers and drinking water for two-thirds of California’s population. Large pump facilities support the water demand and draw water from the Delta, further altering circulation patterns and redirecting the net flow toward the export facilities (Monsen et al., 2007). Fluvial sedimentation, along with organic accumulation, creates and sustains the Delta landscape. Hydraulic mining for gold in the watershed during the late 1800s delivered an especially large sediment pulse to the Delta. More recently, from 1955 to the present, a significant sediment decline has been observed that is thought to have been caused mostly by the construction of water storage reservoirs that trap the upstream sediment supply (Wright and Schoellhamer, 2004). Today, one concern is whether the volume of sediment supplied from the upper watershed is sufficient to support ecological function and sustain the Delta landscape and ecosystem in the face of climate change, sea level rise, and proposed restoration associated with the Bay Delta Conservation Plan (http://baydeltaconservationplan.com). Ecosystem health is a management focus and 150,000 acres of restoration is currently proposed, therefore it is of increasingly important to understand the quantity of sediment available for marsh and wetland restoration throughout the Bay Delta Estuary. It is also important to understand the pathways for sediment transport and the sediment budget into each of three Delta regions (figure 1) to guide restoration planning, modeling, and management.

California↗

USGS2022

Measuring and attributing sedimentary and geomorphic responses to modern climate change: Challenges and opportunities

Today, climate change is affecting virtually all terrestrial and nearshore settings. This commentary discusses the challenges of measuring climate-driven physical landscape responses to modern global warming: short and incomplete data records, land use and seismicity masking climatic effects, biases in data availability and resolution, and signal attenuation in sedimentary systems. We identify opportunities to learn from historical and paleo data, select especially sensitive study sites, and report null results to better characterize the extent and nuances of climate-change effects. We then discuss efforts to improve attribution practices, which will lead to better predictive capabilities. We encourage the earth-science community to prioritize scientific research on climate-driven physical landscape changes so that societies will be better prepared to manage the effects on health and safety, infrastructure, water–food–energy security, economics, and ecosystems that follow from climate-driven physical landscape change.

Earth's Future↗

USGS1991

On seismological moments and magnitudes

My approach to seismology over the years has always been from the point of view of applied mathematics, as exemplified broadly by the work of the late Sir Harold Jeffreys and Professor K. E. Bullen. Both stresses the development of mathematics in the context of physical systems and of modeling, with an eye always on the side of inference. Seismology provided for them and still provides today the almost perfect paradigm; the problem is the resolution of the detailed consitution of the Earth and its geologically short-term dynamics. The latter part, includes, of course, seismic-risk estimation. The last 20 years have seen the construction of a brilliant theoretical formalism for linear inverse problems in seismology , although, oddly enough, the current popular Earth models do not take account it. It is interesting too that the narrow opinion, prevelent a decade ago, to the effect that the traditional seismic body-wave approaches to structural definition were superceded, has been largely abandoned under today's banner of tomography-as though the Oldham-Jeffreys-Gutenbery inversions were not tomography.

Earthquakes & Volcanoes (USGS)↗

USGS1994

Remote sensing and airborne geophysics in the assessment of natural aggregate resources

Natural aggregate made from crushed stone and deposits of sand and gravel is a vital element of the construction industry in the United States. Although natural aggregate is a high volume/low value commodity that is relatively abundant, new sources of aggregate are becoming increasingly difficult to find and develop because of rigid industry specifications, political considerations, development and transporation costs, and environmental concerns, especially in urban growth centers where much of the aggregate is used. As the demand for natural aggregate increases in response to urban growth and the repair and expansion of the national infrastructure, new sources of natural aggregate will be required. The USGS has recognized the necessity of developing the capability to assess the potential for natural aggregate sources on Federal lands; at present, no methodology exists for systematically describing and evaluating potential sources of natural aggregate. Because remote sensing and airborne geophysics can detect surface and nearsurface phenomena, these tools may useful for detecting and mapping potential sources of natural aggregate; however, before a methodology for applying these tools can be developed, it is necessary to understand the type, distribution, physical properties, and characteristics of natural aggregate deposits, as well as the problems that will be encountered in assessing their potential value. There are two primary sources of natural aggregate: (1) exposed or near-surface igneous, metamorphic, and sedimentary bedrock that can be crushed, and (2) deposits of sand and gravel that may be used directly or crushed and sized to meet specifications. In any particular area, the availability of bedrock suitable for crushing is a function of the geologic history of the area - the processes that formed, deformed, eroded and exposed the bedrock. Deposits of sand and gravel are primarily surficial deposits formed by the erosion, transportation by water and ice, and deposition of bedrock fragments. Consequently, most sand and gravel deposits are Tertiary or Quaternary in age and are most common in glaciated areas, alluvial basins, and along rivers and streams. The distribution of potential sources of natural aggregate in the United States is closely tied to physiography and the type of bedrock that occurs in an area. Using these criteria, the United States can be divided into 12 regions: western mountain ranges, alluvial basins, Columbia Plateau, Colorado Plateau and Wyoming basin, High Plains, nonglaciated central region, glaciated central region, Piedmont Blue Ridge region, glaciated northeastern and Superior uplands, Atlantic and Gulf coastal plain, Hawaiian Islands, and Alaska. Each region has similar types of natural aggregate sources within its boundary, although there may be wide variations in specific physical and chemical characteristics of the aggregates within a region. Conventional exploration for natural aggregate deposits has been largely a ground-based operation (field mapping, sampling, trenching and augering, resistivity), although aerial photos and topographic maps have been extensively used to target possible deposits for sampling and testing. Today, the exploration process also considers other factors such as the availability of the land, space and water supply for processing purposes, political and environmental factors, and distance from the market; exploration and planning cannot be separated. There are many physical properties and characteristics by which aggregate material is judged to be acceptable or unacceptable for specific applications; most of these properties and characteristics pertain only to individual aggregate particles and not to the bulk deposit. For example, properties of crushed stone aggregate particles such as thermal volume change, solubility, oxidation and hydration reactivity, and particle strength, among many others, are important consi

Open-File Report↗

USGS1999

Physical, chemical, and isotopic data for samples from the Anderson Springs area, Lake County, California, 1998-1999

Anderson Springs is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. In the rugged hills to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. In the 1970s, the high-elevation areas surrounding Anderson Springs became part of The Geysers geothermal field. Today, several electric powerplants are located on the ridges above Anderson Springs, utilizing steam produced from a 240°C vapor-dominated reservoir. The primary purpose of this report is to provide physical, chemical, and isotopic data on samples collected in the Anderson Springs area during 1998 and 1999, in response to a Freedom of Information Act request. In July 1998, drainage from the Schwartz adit of the abandoned Anderson mercury mine increased substantially over a 2-day period, transporting a slurry of water and precipitates down a tributary and into Anderson Creek. In August 1998, J.J. Rytuba and coworkers sampled the Schwartz adit drainage and water from the Anderson Springs Hot Spring for base metal and methylmercury analysis. They measured a maximum temperature (Tm) of 85°C in the Hot Spring. Published records show that the temperature of the Anderson Springs Hot Spring (main spring) was 63°C in 1889, 42–52°C from 1974 through 1991, and 77°C in March 1995. To investigate possible changes in thermal spring activity and to collect additional samples for geochemical analysis, C.J. Janik and coworkers returned to the area in September and December 1998. They determined that a cluster of springs adjacent to the main spring had Tm=98°C, and they observed that a new area of boiling vents and small fumaroles (Tm=99.3°C) had formed in an adjacent gully about 20 meters to the north of the main spring. During August–October 1999, several field trips were conducted in the vicinity of Anderson Springs to continue monitoring and sampling the thermal manifestations. The new fumarolic area had increased in temperature and in discharge intensity since 1998, and a zone of dead trees had developed on the steep bank directly west of the fumaroles. Ground temperatures and diffuse flow of CO2 flow through soils were measured in the area surrounding the main spring and new fumaroles and in the zone of tree-kill.

California↗

USGS2016

Synthesis and revision of the lithostratigraphic groups and formations in the Upper Permian?–Lower Jurassic Newark Supergroup of eastern North America

The Upper Permian? - Lower Jurassic Newark Supergroup of eastern North America has a strikingly uniform succession of lithologic units. This uniformity is seen regardless of whether these units are characterized on the basis of their lithostratigraphy, allostratigraphy, biostratigraphy, or chemostratigraphy. After deposition, these units were broken up tectonically and attacked erosionally; parts of them survive today only within localized, down-faulted areas. Many lines of evidence compellingly demonstrate that most or all of these remnant units once were physically continuous between remaining outcrops. It is needlessly confusing to give every remnant of each unit a different name in each area where it persists simply because it is now physically isolated by erosion from other portions of the same unit. Instead, these units should be defined within a regional lithostratigraphic framework that emphasizes their common origins and original stratigraphic continuity. To this end, the formation-level stratigraphy of the Newark Supergroup is reduced from 58 locally applied and locally defined formations to a succession of only 16 uniformly defined and regionally recognizable formations. In all cases the oldest name validly applied to each formation is given priority over more recently erected synonymous names, which are either abandoned or, in a few cases, changed in rank to a member of one of the formations recognized here. The Newark Supergroup is here organized into four regionally recognizable groups, each subdivided into regionally recognizable formations. In ascending order, the Upper Permian?-Middle Triassic Acadia Group (new name) includes the Honeycomb Point Formation, Chedabucto Formation, Economy Formation, and Evangeline Formation. This group is preserved only in the Canadian Fundy and Chedabucto basins. The Upper Triassic (Carnian-Norian) Chatham Group includes the Doswell Formation, Stockton Formation, Lockatong Formation, and Passaic Formation. The Upper Triassic-Lower Jurassic (upper Rhaetian-lower Hettangian) Meriden Group includes the Talcott Formation, Shuttle Meadow Formation, Holyoke Formation, East Berlin Formation, and Hampden Formation. The term "Agawam Group," previously proposed to encompass all Newark Supergroup strata above the highest basalt of the Meriden Group, is here abandoned and replaced with the name "Portland Group" for the same suite of strata. The Lower Jurassic (upper Hettangian-lower Sinemurian) Portland Group includes a lower Boonton Formation, an overlying Longmeadow Sandstone (here reinstated), and the Mount Toby Conglomerate, which laterally intertongues with both the Boonton Formation and the Longmeadow Sandstone.

Stratigraphy↗

USGS2018

Rare earth element and rare metal inventory of central Asia

Rare earth elements (REE), with their unique physical and chemical properties, are an essential part of modern living. REE have enabled development and manufacture of high-performance materials, processes, and electronic technologies commonly used today in computing and communications, clean energy and transportation, medical treatment and health care, glass and ceramics, aerospace and defense, and metallurgy and chemical refining. Central Asia is an emerging REE and rare metals (RM) producing region. A newly compiled inventory of REE-RM-bearing mineral occurrences and delineation of areas-of-interest indicate this region may have considerable undiscovered resources.

Fact Sheet↗

USGS2005

A legacy of change: The lower Colorado River, Arizona-California-Nevada, USA, and Sonora-Baja California Norte, Mexico

The lower Colorado is among the most regulated rivers in the world. It ranks as the fifth largest river in volume in the coterminous United States, but its flow is fully allocated and no longer reaches the sea. Lower basin reservoirs flood nearly one third of the river channel and store 2 years of annual flow. Diverted water irrigates 1.5 million ha of cropland and provides water for industry and domestic use by 22 million people in the southwestern United States and northern Mexico. The native fish community of the lower Colorado River was among the most unique in the world, and the main stem was home to nine freshwater species, all of which were endemic to the basin. Today, five are extirpated, seven are federally endangered, and three are being reintroduced through stocking. Decline of the native fauna is attributed to predation by nonnative fishes and physical habitat degradation. Nearly 80 alien species have been introduced, and more than 20 now are common. These nonnative species thrived in modified habitats, where they largely eliminated the native kinds. As a result, the lower Colorado River has the dubious distinction of being among the few major rivers of the world with an entirely introduced fish fauna. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗

USGS1975

Environmental problems in the coastal and wetlands ecosystems of Virginia Beach, Virginia

Many of the city of Virginia Beach's beach stabilization and sewage disposal problems are the result of an inadequate understanding of the physical and biological systems. Influenced by population and economic pressures, natural systems were artificially stabilized by engineering projects that had to be constantly maintained. These same pressures continue to prevail today in spite of a new environmental awareness; changes are occurring very slowly. Furthermore, the lack of adequate sewage disposal facilities and the continued urbanization of inappropriate areas are threatening Virginia Beach's attractiveness as a resort area.

North Carolina;Virginia↗

USGS1990

Paleoclimatic implications of the high stand of Lake Lahontan derived from models of evaporation and lake level

Based on previous climate model simulations of a split of the polar jet stream during the late Pleistocene, we hypothesize that (1) 20-13.5 ka BP, season-to-season variation in the latitudinal maximum of the jet stream core led to enhanced wetness in the Great Basin, and (2) after 13.5 ka BP, northward movement of the jet stream resulted in increased aridity similar to today. We suggest that the enhanced effective wetness was due to increased precipitation combined with an energy-limited reduction in evaporation rates that was caused by increased summer cloud cover. A physically based thermal evaporation model was used to simulate evaporation for Lake Lahontan under various hypothesized paleoclimates. The simulated evaporation rates, together with hypothetical rates of precipitation and discharge, were input to a water balance model of Lake Lahontan. A 42% reduction in evaporation rate, combined with maximum historical rates of precipitation (1.8 times the mean annual rate) and discharge (2.4 times the mean annual rate), were sufficient to maintain Lake Lahontan at its 20-15 ka BP level. When discharge was increased to 3.8 times the present-day, mean annual rate, the ??? 13.5 ka BP maximum level of Lake Lahontan was attained within 1400 years. A 135-m drop from the maximum level to Holocene levels was simulated within 300 years under the imposition of the present-day hydrologic balance. ?? 1990 Springer-Verlag.

Climate Dynamics↗

USGS2013

An international network of magnetic observatories

Since its formation in the late 1980s, the International Real-Time Magnetic Observatory Network (INTERMAGNET), a voluntary consortium of geophysical institutes from around the world, has promoted the operation of magnetic observatories according to modern standards [eg. Rasson, 2007]. INTERMAGNET institutes have cooperatively developed infrastructure for data exchange and management ads well as methods for data processing and checking. INTERMAGNET institute have also helped to expand global geomagnetic monitoring capacity, most notably by assisting magnetic observatory institutes in economically developing countries by working directly with local geophysicists. Today the INTERMAGNET consortium encompasses 57 institutes from 40 countries supporting 120 observatories (see Figures 1a and 1b). INTERMAGNET data record a wide variety of time series signals related to a host of different physical processes in the Earth's interiors and in the Earth's surrounding space environment [e.g., Love, 2008]. Observatory data have always had a diverse user community, and to meet evolving demand, INTERMAGNET has recently coordinated the introduction of several new data services.

Eos, Transactions, American Geophysical Union↗

USGS2009

What is a picture worth? A history of remote sensing

Remote sensing is the use of electromagnetic energy to measure the physical properties of distant objects. It includes photography and geophysical surveying as well as newer techniques that use other parts of the electromagnetic spectrum. The history of remote sensing begins with photography. The origin of other types of remote sensing can be traced to World War II, with the development of radar, sonar, and thermal infrared detection systems. Since the 1960s, sensors have been designed to operate in virtually all of the electromagnetic spectrum. Today a wide variety of remote sensing instruments are available for use in hydrological studies; satellite data, such as Skylab photographs and Landsat images are particularly suitable for regional problems and studies. Planned future satellites will provide a ground resolution of 10–80 m. Remote sensing is currently used for hydrological applications in most countries of the world. The range of applications includes groundwater exploration determination of physical water quality, snowfield mapping, flood-inundation delineation, and making inventories of irrigated land. The use of remote sensing commonly results in considerable hydrological information at minimal cost. This information can be used to speed-up the development of water resources, to improve management practices, and to monitor environmental problems.

Hydrological Sciences Bulletin↗