Since August 2013, all 50 states have been available for editing with the USGS The National Map Corps (TNMCorps) volunteered geographic information project. Starting this month, TNMCorps is pleased to add the United States Virgin Islands to that list.
Using crowd-sourcing techniques, TNMCorps encourages citizen volunteers to collect data about manmade structures in an effort to provide accurate and authoritative spatial map data for the USGS National Geospatial Program’s web-based The National Map.
Through an online map editor, volunteers use aerial images and other resources to improve structures data by adding new features, removing obsolete points, and correcting existing data. Points available to edit include schools, hospitals, post offices, police stations and other important public buildings. Volunteers may find editing structures in the U.S. Virgin Islands quite challenging, as some source data points shown in the map editor may be out of date, and some structure types are missing entirely.
One of many younger volunteers has found that contributing to The National Map Corps has been a rewarding summer activity. “I’ve only been working for a month and already I’ve discovered interesting facts, like where Sacagawea is buried, and all of the unique names for places around the country,” said user “crazeyme,” who is also one of the top producing participants.
To recognize our volunteers, TNMCorps has instituted a recognition program that awards "virtual" badges" based on the number of points edited. Badges consist of a series of antique surveying instruments ranging from the Surveyor's Chain (25 – 50 points) to the Theodolite Assemblage (2000+ points). Additionally, volunteers are publically recognized (with user permission) via Twitter, Google+, and Facebook.
Volunteers only need access to a computer and the Internet to participate. The National Map Corps’ website explains how volunteers can edit any area, regardless of their familiarity with the selected structures. Registration is simple and requires only an email address and self-selected username.
Participants make a significant addition to the USGS's ability to provide accurate information to the public. Data collected by volunteers become part of The National Map structures dataset which is available to users free of charge.
See for yourself how much fun participating can be. Go to The National Map Corps and give it a try.Screen shot of The National Map Corps editor webpage showing the capitol city of Charlotte Amalie on St. Thomas, St. Thomas. Within this image lies the governmental center, public schools, and more– which is why The National Map Corps needs your help! (high resolution image 3.3 MB) Badges awarded for submitting edits, shown in from first to last: Order of the Surveyor’s Chain (25-49), Society of the Steel Tape 50-99), Pedometer Posse (100-199), Surveyor’s Compass (200-499), Stadia Board Society (500-999), Alidade Alliance (1000-1999), and Theodolite Assemblage (2000+). New awards for volunteers exceeding 2,000 points are under review. (high resolution image 114.7KB)
Reporters: Video footage of an interview with lead USGS scientist Parker Norton is available online.
Streamflow in the eastern portions of the Missouri River watershed has increased over the past 52 years, whereas other parts have seen downward trends.
U.S. Geological Survey scientists recently studied data from 227 streamgages in the Missouri River watershed that had continuous records for 1960 through 2011. The scientists found that almost half of the streamgages showed either an upward or downward trend in mean annual flow since 1960, while the rest showed no trend.
The study is relevant on a large scale because the Missouri River is the longest river in the United States, with a watershed that includes mountainous to prairie topography in all or parts of 10 states and small parts of Alberta and Saskatchewan in Canada.
“The Missouri River and its tributaries are valuable for agriculture, energy, recreation and municipal water supplies,” said USGS hydrologist Parker Norton. “Understanding streamflow throughout the watershed can help guide management of these critical water resources.”
According to the study, streamflow has increased in the eastern part of the watershed, including eastern North Dakota, eastern South Dakota, western Iowa and eastern Nebraska. Annual flows have decreased in the western headwaters area of the Missouri River in Montana and Wyoming, and in the southern part of the basin associated with the Kansas River watershed.
Climate changes that affect how and where moisture is delivered to the continent may be causing some of these trends in the Missouri River Basin. Although the USGS scientists did not conduct a complete analysis of the causes, they noted that increased streamflow over broad regions occurred despite the increasing use of water. Decreased streamflow in some areas could also be related to climate change factors, or to groundwater pumping.
The USGS report can be accessed online.
For more than 125 years, the USGS has monitored flow in selected streams and rivers across the United States. The information is routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk and for many recreational activities.
Access current flood and high flow conditions across the country by visiting the USGS WaterWatch website. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.
RALEIGH, N.C.—Urban areas in the Southeastern United States will double in size by 2060 unless there are significant changes to land development, according to a new study by the Department of Interior’s Southeast Climate Science Center and North Carolina State University.
The predicted growth would come at the expense of agricultural and forest lands, creating an urban “megalopolis” stretching from Raleigh to Atlanta, which also raises a number of ecological concerns.
“If we continue to develop urban areas in the Southeast the way we have for the past 60 years, we can expect natural areas will become increasingly fragmented,” said Adam Terando, a research ecologist with the U.S. Geological Survey, adjunct assistant professor at NC State, and lead author of the study. “We could be looking at a seamless corridor of urban development running from Raleigh to Atlanta, and possibly as far as Birmingham, within the next 50 years.”
To understand how urban and natural environments could change, the researchers used NC State’s High Performance Computing services to simulate urban development between now and 2060 across the Southeastern United States.
Among the expected impacts of such expansive urban growth, the fragmentation of natural areas would significantly limit the mobility of wildlife, making it more difficult for them to find mates, raise young, find food and respond to environmental changes.
“This, in turn, increases the likelihood that we’ll see more conflicts between people and wildlife, such as the increasing interactions with bears we’re seeing in our suburban areas,” Terando said.
An increase in urbanization would also make urban heat islands—the warming of cities due to human activities and development—more common, favoring species that can take advantage of the hotter conditions in cities. For example, previous studies have found that insect pests – such as scale insects – thrive in urban environments.
“Unless we change course, over the next 50 years urbanization will have a more pronounced ecological impact in many non-coastal areas of the Southeast than climate change, said Jennifer Costanza, a research associate at NC State and a co-author of the study. “It’s impossible to predict precisely what the specific ecological outcomes would be, but so far, the projections are not good in terms of biodiversity and ecosystem health.”
This research emphasizes how decision makers involved in community planning will need a well-thought out strategy for future development, Costanza said.
“Given that urbanization poses significant challenges to this region, decision makers will need to begin serious, long-term discussions about economic development, ecological impacts and the value of non-urban spaces,” she added.
The paper, “The southern megalopolis: using the past to predict the future of urban sprawl in the Southeast U.S.,” is published in PLOS ONE. The paper was co-authored by Adam Terando, Alexa McKerrow and Jaime A. Collazo of the USGS; and Jennifer Costanza, Curtis Belyea and Rob Dunn of NC State. The work was supported by the DOI Southeast Climate Science Center based at NC State. The center provides scientific information to help natural resource managers respond effectively to climate change.
Caribou from the Central Arctic herd along the Sagavanirktok River in northern Alaska. (High resolution image)
ANCHORAGE, Alaska — Due to climate change, some communities in rural Alaska and the Yukon Territory of Canada may face a future with fewer caribou according to new research published by the U.S. Geological Survey and the University of Alaska, Fairbanks in the recent issue of PLoS ONE. Scientists examined the future effects of fires on winter habitats of caribou herds and determined that wildfires will reduce the amount of winter habitat for caribou, thus caribou may need to shift their wintering grounds
Warming temperatures will increase the flammability of lichen-producing boreal forests, which are important winter habitat for caribou herds. Caribou serve as nutritional as well as cultural sustenance for certain communities. Caribou avoid burned areas in winter and the changes in their distribution can persist across multiple generations of hunters. Those who rely on caribou in fire-prone areas may therefore have fewer available as climate change increases the number and sizes of fires in the boreal forests.
“We project that the Porcupine caribou herd will lose 21% of winter habitat to fire by the end of this century, with the majority of this loss driven by increased flammability in spruce forests in the Yukon," said Dr. Dave Gustine, a Research Wildlife Biologist with the USGS and lead author of the study.
The study examines how increasing temperatures will influence flammability of boreal forest areas used by the Central Arctic and Porcupine caribou herds during winter. Understanding possible changes to forest flammability allows forecasting of future winter distributions of caribou that will impact subsistence harvest and land, wildlife and fire management programs.
Climate change is global in scope and scale; however, its impacts are sometimes most visible in remote locations of the planet. Like climate change itself, migratory animals such as caribou do not recognize international geo-political borders and the research needed to study the relationship between climate change and animals crosses many countries.
The potential changes in caribou distribution will affect communities that have a cultural and nutritional reliance on caribou. Arctic Village, Alaska and Old Crow Yukon Territory, are within the traditional boreal forest winter range of the Porcupine herd, while hunters from the Alaskan villages of Fort Yukon, Venetie and Chalkyitsik, travel north each year to harvest animals from this herd.
“Fires were less numerous and smaller in tundra habitats compared to spruce habitats and given the more likely climate trajectory, we projected that the Porcupine caribou herd, which winters primarily in the boreal forest, could be expected to experience a greater reduction in lichen-producing winter habitats than the Central Arctic herd that wintered primarily in the arctic tundra,” said Dr. Todd Brinkman a co-author of the study and member of the Scenarios Network for Alaska and Arctic Planning at the University of Alaska, Fairbanks.
Future work by the USGS and collaborators will examine how fire-driven changes to winter habitat and temperature-driven changes to spring and summer forages will influence the habitats of caribou across the Alaskan Arctic.
This work is part of the USGS Changing Arctic Ecosystems Initiative.Simulation domain and winter ranges of the Central Arctic and Porcupine caribou herds, Alaska and Yukon. (High resolution image)
Insecticides similar to nicotine, known as neonicotinoids, were found commonly in streams throughout the Midwest, according to a new USGS study. This is the first broad-scale investigation of neonicotinoid insecticides in the Midwestern United States and one of the first conducted within the United States.
Effective in killing a broad range of insect pests, use of neonicotinoid insecticides has dramatically increased over the last decade across the United States, particularly in the Midwest. The use of clothianidin, one of the chemicals studied, on corn in Iowa alone has almost doubled between 2011 and 2013.
“Neonicotinoid insecticides are receiving increased attention by scientists as we explore the possible links between pesticides, nutrition, infectious disease, and other stress factors in the environment possibly associated with honeybee dieoffs.” said USGS scientist Kathryn Kuivila, the research team leader.
Neonicotinoid insecticides dissolve easily in water, but do not break down quickly in the environment. This means they are likely to be transported away in runoff from the fields where they were first applied to nearby surface water and groundwater bodies.
In all, nine rivers and streams, including the Mississippi and Missouri Rivers, were included in the study. The rivers studied drain most of Iowa, and parts of Minnesota, Montana, Nebraska, North Dakota, South Dakota, and Wisconsin. These states have the highest use of neonicotinoid insecticides in the Nation, and the chemicals were found in all nine rivers and streams.
Of the three most often found chemicals, clothianidin was the most commonly detected, showing up in 75 percent of the sites and at the highest concentration. Thiamethoxam was found at 47 percent of the sites, and imidacloprid was found at 23 percent. Two, acetamiprid and dinotefuran, were only found once, and the sixth, thiacloprid, was never detected.
Instead of being sprayed on growing or full-grown crops, neonicotinoids can be applied to the seed before planting. The use of treated seeds in the United States has increased to the point where most corn and soybeans planted in the United States have a seed treatment (i.e., coating), many of which include neonicotinoid insecticides.
“We noticed higher levels of these insecticides after rain storms during crop planting, which is similar to the spring flushing of herbicides that has been documented in Midwestern U.S. rivers and streams,” said USGS scientist Michelle Hladik, the report’s lead author. “In fact, the insecticides also were detected prior to their first use during the growing season, which indicates that they can persist from applications in prior years.”
One of the chemicals, imidacloprid, is known to be toxic to aquatic organisms at 10-100 nanograms per liter if the aquatic organisms are exposed to it for an extended period of time. Clothianidin and thiamethoxam behave similarly to imidacloprid, and are therefore anticipated to have similar effect levels. Maximum concentrations of clothianidin, thiamethoxam and imidacloprid measured in this study were 257, 185, and 42.7 nanograms per liter, respectively.
The U.S. Environmental Protection Agency has classified all detected neonicotinoids as not likely to be carcinogenic to humans.
The paper, “Widespread occurrence of neonicotinoid insecticides in streams in a high corn and soybean producing region, USA” and has been published in Environmental Pollution. Learn more about the study and the long-term USGS effort to gather information on the environmental occurrence of new pesticides in different geographic, climatic, and use settings here. To learn more about USGS environmental health science, please visit the USGS Environmental Health website and sign up for our GeoHealth Newsletter.Locations of sites in Iowa sampled for neonicotinoids in 2013. Watersheds for the Mississippi River and Missouri River sites are shown in the inset.
Outdated and inconsistent elevation data cost lives and hinder prosperity across our Nation. Current and accurate 3D elevation data are essential to help communities cope with natural hazards, support infrastructure, ensure agricultural success, strengthen environmental decision making and bolster national security. Flood and landslide maps are just a few of the hundreds of applications benefiting from enhanced lidar data. A coordinated effort among Federal, State, local government and the private sector could meet our country’s needs for high-quality, 3D elevation data in just 8 years. Come learn how the USGS and its partners are working to assemble and apply better data to keep citizens safe and help America thrive.Speakers:
- Douglas Bausch – Region VIII Earthquake Program Manager and Senior Physical Scientist, Federal Emergency Management Agency
- John Dorman – Assistant State Emergency Management Director for Geospatial & Technology Management, North Carolina
- Jonathan Godt- Landslide Hazards Program Coordinator, U.S. Geological Survey
Emcee: Kevin Gallagher – Associate Director for Core Science Systems, USGS
Where: Rayburn House Office Building, Room 2325, Washington, D.C.
When: Friday, July 25, 2014 - 11:00 a.m.
Host: Refreshments provided courtesy of Management Association for Private Photogrammetric Surveyors (MAPPS)
High-resolution lidar image of Mount St. Helens, Washington.
The USGS, along with other federal, state, local and private agencies is establishing a new 3D Elevation Program (3DEP) designed to respond to the growing needs for three-dimensional mapping data of the United States. This coordinated partnership can help meet the country’s needs for high-quality, 3D elevation data.
Current and accurate 3D elevation data are essential to help communities cope with natural hazards and disasters such as floods and landslides, support infrastructure, ensure agricultural success, strengthen environmental decision-making and bolster national security.
The primary goal of the 3DEP partnership is to systematically collect 3D elevation data across the Nation, using lidar, a remote sensing detection system that works on the principle of radar, but uses light from a laser.
“We are excited about working with partners to apply the game-changing technology of lidar to benefit many critical needs of national importance,” said Kevin Gallagher, USGS Associate Director of Core Science Systems. “For example, FEMA and NOAA are some of our strongest partners because they rely on this type of data to significantly improve floodplain mapping and to better communicate flood risks to communities and citizens.”
The 3DEP initiative is based on the results of the National Enhanced Elevation Assessment that documented more than 600 business and science uses across 34 Federal agencies, all 50 States, selected local government and Tribal offices, and private and nonprofit organizations. The assessment also shows that 3DEP would provide more than $690 million annually in new benefits to government entities, the private sector, and citizens.
A recent White House fact sheet described how accessibility of accurate, high-quality 3D elevation data provides the foundation to the Administration’s overall plan to assist populations in the areas of flood risk management, water resource planning, mitigation of coastal erosion and storm surge impacts, and identification of landslide hazards.
The USGS will host a briefing on Capitol Hill on July 25 to further describe the importance, benefits and growing needs for 3D elevation data.
More information about 3DEP and state specific fact sheets is available online.A comparison of an air photo and a lidar image of an area along Secondary Road and Camp Creek, 12 miles north of John Day, OR. The lidar image allows identification of landslide activity that is otherwise masked by trees. (Photo courtesy of the Oregon Department of Geology and Mineral Industries).
The U.S. Geological Survey joins its many partners in other federal agencies, at universities, and in state and local governments in recognizing the importance of the Water Resources Research Act (WRRA) of 1964.
Signed into law 50 years ago by President Lyndon B. Johnson on July 17, 1964, the WRRA established a Water Resources Research Institute in each state and Puerto Rico. “Abundant, good water is essential to continued economic growth and progress,” said President Johnson at the time in a prepared statement. “The Congress has found that we have entered a period in which acute water shortages are hampering our industries, our agriculture, our recreation, and our individual health and happiness.”
“Water makes life on Earth possible, defines our landscape, and shapes our natural heritage. It is key to our continued prosperity,” observed Anne Castle, assistant secretary for water and science at the Department of the Interior. “The keen appreciation of the importance of water resources that was expressed by our nation’s leaders in 1964 appears even more visionary today as we are facing the challenges of population growth, increased demand, and climate change.”
The WRRA’s geographically distributed approach to water research and education, Johnson’s 1964 statement continued, “will enlist the intellectual power of universities and research institutes in a nationwide effort to conserve and utilize our water resources for the common benefit. The new centers will be concerned with municipal and regional, as well as with national water problems. Their ready accessibility to state and local officials will permit each problem to be attacked on an individual basis, the only way in which the complex characteristics of each water deficiency can be resolved.”
Subsequent amendments to the 1964 act broadened the list of National Institutes for Water Resources (NIWR) so that, by 1983, there were 54 institutes, one in each state, the District of Columbia, Puerto Rico, the U.S. Virgin Islands, and Guam.
The Water Resources Research Institute Program originally authorized by WRRA in 1964 is a federal-state partnership that provides for competitive grants to be awarded for research projects focusing on the state and region. Each of the 54 institutes is charged with overseeing competent research that addresses water problems or expands the understanding of water and water-related phenomena. They are also responsible for aiding the entry of new research scientists into water resources fields, helping to train future water scientists and engineers, and transferring the results of sponsored research to water managers and the public.
“The water research partnerships fostered by the Water Resources Research Act are unparalleled,” said Sharon Megdal, Director of the University of Arizona Water Resources Research Center and president-elect of NIWR. “The network of Water Resources Research Institutes connects within states, across regions, and with USGS and other federal agencies to tackle the most pressing water resource challenges of our nation."
Fifty years later, the Water Resources Research Institutes, in partnership with the U.S. Geological Survey, continue to fulfill their roles assigned by Congress in 1964. They have produced path-breaking research, developed innovative information and technology transfer programs, and provided training to more than 25,000 students in their 50-year history.
- National Institutes for Water Resources (NIWR)
- Statement of President Lyndon B. Johnson on the occasion of the approval of the Water Resources Research Act of 1964, July 17, 1964.
- History of Water Resources Research Institutes program
Robin Fergason ( Phone: 928-556-7034 );
TEMPE, Ariz. – A heat-sensing camera designed at Arizona State University has provided data to create the most detailed global map yet of Martian surface properties. The map uses data from the Thermal Emission Imaging System (THEMIS), a nine-band visual and infrared camera on NASA’s Mars Odyssey orbiter. An online version of the map optimized for scientific researchers is also available.
The new Mars map was developed by Robin Fergason of the U.S. Geological Survey Astrogeology Science Center in Flagstaff, Arizona, in collaboration with researchers at ASU's Mars Space Flight Facility. The work reflects the close ties between space exploration efforts at Arizona universities and the USGS.
"We used more than 20,000 THEMIS nighttime temperature images to generate the highest resolution surface property map of Mars ever created," said Fergason, who earned her Ph.D. degree at ASU in 2006. "Now these data are freely available to researchers and the public alike."
Surface properties tell geologists about the physical nature of a planet or moon's surface. Is a particular area coated with dust, and if so, how thick is it likely to be? Where are the outcrops of bedrock? How loose are the sediments that fill this crater or that valley? A map of surface properties lets scientists begin to answer such questions.
The new map uses nighttime temperature images to derive the "thermal inertia" for football field-sized areas of Mars. Thermal inertia is a calculated value that represents how fast a surface heats up and cools off. As night follows day on Mars, loose fine-grain materials such as sand and dust change temperature quickly and thus have low values of thermal inertia. Bedrock has a high thermal inertia because it cools off slowly at night and warms up slowly by day.
"Darker areas in the map have a lower thermal inertia and likely contain fine particles, such as dust, silt or fine sand," said Fergason. “Brighter regions have higher thermal inertia surfaces, consisting perhaps of coarser sand, surface crusts, rock fragments, bedrock or combinations of these materials.”
The designer and principal investigator for the THEMIS camera is Philip Christensen, Regents' Professor of Geological Sciences in the School of Earth and Space Exploration, part of the College of Liberal Arts and Sciences on the Tempe campus. Four years ago, Christensen and ASU researchers used daytime THEMIS images to create a global Mars map depicting the planet's landforms, such as craters, volcanoes, outflow channels, landslides, lava flows and other features.
"A tremendous amount of effort has gone into this great global product, which will serve engineers, scientists and the public for many years to come," Christensen said. "This map provides data not previously available and will enable regional and global studies of surface properties. I'm eager to use it to discover new insights into the recent surface history of Mars."
Fergason noted that there's a practical side, too.
"NASA used THEMIS images to find safe landing sites for the Mars Exploration Rovers in 2004 and Curiosity, the Mars Science Laboratory rover, in 2012," she said. "THEMIS images are now helping to select a landing site for NASA's next Mars rover in 2020."
This new global geologic map of Mars depicts the most thorough representation of the “Red Planet’s” surface. This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration.(High resolution image)
A new global geologic map of Mars –the most thorough representation of the "Red Planet's" surface – has been published by the U.S. Geological Survey. This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration.
The new map brings together observations and scientific findings from four orbiting spacecraft that have been acquiring data for more than 16 years. The result is an updated understanding of the geologic history of the surface of Mars – the solar system’s most Earth-like planet and the only other one in our Sun’s “habitable zone.” The new geologic map of Mars is available for download online.
For hundreds of years, geologic maps have helped drive scientific thought. This new global geologic map of Mars, as well as the recent global geologic maps of Jupiter’s moons Ganymede and Io, also illustrates the overall importance of geologic mapping as an essential tool for the exploration of the solar system.
"Spacecraft exploration of Mars over the past couple decades has greatly improved our understanding of what geologic materials, events and processes shaped its surface," said USGS scientist and lead author, Dr. Kenneth Tanaka. “The new geologic map brings this research together into a holistic context that helps to illuminate key relationships in space and time, providing information to generate and test new hypotheses.”
The USGS-led mapping effort reveals that the Martian surface is generally older than previously thought. Three times as much surface area dates to the first major geologic time period - the Early Noachian Epoch - than was previously mapped. This timeframe is the earliest part of the Noachian Period, which ranges from about 4.1 to about 3.7 billion years ago, and was characterized by high rates of meteorite impacts, widespread erosion of the Martian surface and the likely presence of abundant surface water.
The map also confirms previous work that suggests Mars had been geologically active until the present day. There is evidence that major changes in Mars’ global climate supported the temporary presence of surface water and near-surface groundwater and ice. These changes were likely responsible for many of the major shifts in the environments where Martian rocks were formed and subsequently eroded. This new map will serve as a key reference for the origin, age and historic change of geological materials anywhere on Mars.
"Findings from the map will enable researchers to evaluate potential landing sites for future Mars missions that may contribute to further understanding of the planet’s history," said USGS Acting Director Suzette Kimball. "The new Mars global geologic map will provide geologic context for regional and local scientific investigations for many years to come."
The Martian surface has been the subject of scientific observation since the 1600s, first by Earth-based telescopes, and later by fly-by missions and orbiting spacecraft. The Mariner 9 and Viking Orbiter missions produced the first planet-wide views of Mars’ surface, enabling publication of the first global geologic maps (in 1978 and 1986-87, respectively) of a planetary surface other than the Earth and the Moon. A new generation of sophisticated scientific instruments flown on the Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter spacecraft has provided diverse, high quality data sets that enable more sophisticated remapping of the global-scale geology of Mars.
The production of planetary cartographic products has been a focal point of research at the USGS Astrogeology Science Center since its inception in the early 1960s. USGS began producing planetary maps in support of the Apollo Moon landings, and continues to help establish a framework for integrating and comparing past and future studies of extraterrestrial surfaces. In many cases, these planetary geologic maps show that, despite the many differences between bodies in our solar system, there are many notable similarities that link the evolution and fate of our planetary system together.
The project was funded by NASA through its Planetary Geology and Geophysics Program.
The mission of the USGS Astrogeology Science Center is to serve the Nation, the international planetary science community, and the general public’s pursuit of new knowledge of our solar system. The Team’s vision is to be a national resource for the integration of planetary geosciences, cartography, and remote sensing. As explorers and surveyors, with a unique heritage of proven expertise and international leadership, USGS astrogeologists enable the ongoing successful investigation of the solar system for humankind. For more information, visit Astrogeology Science Center
Jennifer LaVista ( Phone: 303-202-4764 );
Seasonal carbon dioxide frost, not liquid water, is the main driver in forming gullies on Mars today, according to a recent U.S. Geological Survey study that relied on NASA’s Mars Reconnaissance Orbiter’s (MRO) repeated high-resolution observations.
Martian gullies are landforms typically consisting of steep channels, usually having a recessed head, that feed into a fan of material deposited at the bottom. The discovery of active gullies was first reported in 2000, which generated excitement due to consideration that they might result from action of liquid water. Mars has water vapor and plenty of water ice, but liquid water, a necessity for all known life, has not been confirmed on modern Mars. The new report, published in the journal Icarus, is available online.
"As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water," said USGS scientist Colin Dundas, lead author of the new report. "We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity is in winter."
A smaller type of seasonal flow seen on some slopes on Mars may involve liquid water, but is yet to be determined. These flows are called recurring slope lineae (RSL), and are sometimes found within small channels but not systematically associated with larger gullies.
Dundas and collaborators used the High Resolution Imaging Science Experiment (HiRISE) camera on MRO to examine each of 356 Martian sites with gullies at least twice, beginning in 2006. Thirty-eight of the sites showed activity, such as cutting a new channel segment or adding material to the apron-shaped deposit at the downhill end of a gully. Wherever the timing of before-and-after observations enabled determining the season of gully activity, it was a time too cold for the possibility of melting water-ice, but consistent with seasonal carbon dioxide frost.
"RSL and mass movements in Martian gullies are two distinct types of slope activity,” said Dundas “It's not hard to tell them apart in HiRISE images. The classic Martian gullies are much larger than RSL. Many of them are more the size that you'd call ravines on Earth."
Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but it is plentiful on Mars. It has been linked to active processes on Mars such as geysers of carbon dioxide gas from springtime sublimation of dry ice, and blocks of dry ice that plow lines on sand dunes by sledding down dunes on cushions of sublimated gas. One mechanism for how carbon dioxide frost might drive gully flows is by gas that is sublimating from the frost, providing lubrication for dry material to flow. Another might be slides due to accumulating weight of seasonal frost buildup on steep slopes.
Work by Dundas and others has previously pointed to winter timing of gully formation on dune and non-dune slopes, with suggested involvement of seasonal changes in frozen carbon dioxide. The new report adds evidence for the changes. The findings also make a new point that the pace of gully formation that has now been documented is swift enough that all of the fresh-appearing gullies seen on Mars can be attributed to current processes. Some earlier hypotheses attributing the gullies to action of liquid water have suggested they formed thousands to millions of years ago when climate conditions were possibly more conducive to Mars having liquid water due to variations in the planet's tilt and orbit.
Dundas' co-authors on the new report are Serina Diniega of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and Alfred McEwen of the University of Arizona, Tucson.
"Much of the information we have about gully formation and other active processes on Mars comes from the longevity of MRO and other orbiters,” said Diniega. “This enables repeated observation of sites to examine changes over time."
Data will appear in an upcoming special issue of Icarus with multiple reports about active processes on Mars, including RSL.
"I like that Mars can still surprise us," Dundas said. "Martian gullies are fascinating features where we can investigate a process that we just don't see on Earth."
HiRISE is operated by the University of Arizona. The instrument was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. The Mars Reconnaissance Orbiter Project is managed for NASA's Science Mission Directorate, Washington, by JPL.
Visit the USGS Astrogeology Center to learn more.
Visit HiRISE for more information.
Additional information about MRO is available online.These two images show changes in a gully on Mars, and illustrate that these landforms are evolving rapidly. A rubbly flow (noted by the arrows) has been deposited near the mouth of the channel between the time of the two images. Further up the slope, the channel system has been modified by both erosion and deposition. The timing of such changes is often in winter or early spring, suggesting that they are caused by the carbon dioxide frost that forms in and around most gullies every year. (High resolution image)
ANCHORAGE, Alaska — Monitoring wildlife in the Arctic is difficult. Study areas are cold, barren and often inaccessible. For decades scientists have struggled to study animals, like polar bears, which live in these remote areas. Now researchers at the U.S. Geological Survey have begun testing a new, yet counterintuitive solution – rather then get close to the animals, monitor them from afar. Scientists have started using satellites to observe, count and track polar bears. USGS scientists and their Canadian collaborators have begun analyzing high-resolution satellite images from a part of the Canadian High Arctic to determine the feasibility of using satellites to study polar bear populations.
“We tested the use of satellite technology from DigitalGlobe to count polar bears by tasking the satellite to collect photos from an area where we were also conducting aerial surveys,” said Dr. Todd Atwood, research leader for the USGS Polar Bear Research Program. “We then analyzed the satellite and aerial survey data separately and found that the abundance estimates were remarkably similar.”
The study, which is led by former USGS scientist and current University of Minnesota researcher Dr. Seth Stapleton, is part of an ongoing effort to identify non-invasive technologies to better understand how polar bears respond to the loss of sea ice due to a warming climate. This study tries to determine the number of polar bears and where they reside on Rowley Island in Nunavut’s Foxe Basin during the ice-free summer. “We selected Rowley as our study site because bear density is high during summer and the flat terrain provides an ideal setting to evaluate the use of satellite imagery,” said Stapleton.
Traditionally, scientists study polar bears by capturing and tagging them or by conducting aerial surveys with low flying aircraft. While these methods provide a wealth of important information, they are disruptive to the animals and are often not possible when dealing with remote locations. “We think satellite technology has the potential to open vast, remote regions of the Arctic to regular monitoring. It has tremendous potential to aid the circumpolar management of polar bears,” said Stapleton.
The next steps in the research focus on testing the satellites’ ability to detect polar bear populations over larger areas, including sites along coastal Alaska. Using satellite imagery shows incredible promise and provides one more tool for those interested in preserving polar bear populations for future generations.