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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 1,639 records · Page 91Linked to original sources
USGS1996

Differentiating climatic and successional influences on long-term development of a marsh

Comparison of long—term records of local wetland vegetation dynamics with regional, climate—forced terrestrial vegetation changes can be used to differentiate the rates and effects of autogenic successional processes and allogenic environmental change on wetland vegetation dynamics. We studied Holocene plant macrofossil and pollen sequences from Portage Marsh, a shallow, 18—ha marsh in northeastern Indiana. Between 10 000 and 5700 yr BP the basin was occupied by a shallow, open lake, while upland vegetation consisted of mesic forests of Pinus, Quercus, Ulmus, and Carya. At 5700 yr BP the open lake was replaced rapidly by a shallow marsh, while simultaneously Quercus savanna developed on the surrounding uplands. The marsh was characterized by periodic drawdowns, and the uplands by periodic fires. Species composition of the marsh underwent further changes between 3000 and 2000 yr BP. Upland pollen spectra at Portage Marsh and other sites in the region shifted towards more mesic vegetation during that period. The consistency and temporal correspondence between the changes in upland vegetation and marsh vegetation indicate that the major vegetational changes in the marsh during the Holocene resulted from hydrologic changes forced by regional climate change. Progressive shallowing of the basin by autogenic accumulation of organic sediment constrained vegetational responses to climate change but did not serve as the direct mechanism of change.

Ecology↗
USGS2017

DOI/GTN-P Climate and active-layer data acquired in the National Petroleum Reserve–Alaska and the Arctic National Wildlife Refuge, 1998–2015

This report provides data collected by the climate monitoring array of the U.S. Department of the Interior on Federal lands in Arctic Alaska over the period August 1998 to July 2015; this array is part of the Global Terrestrial Network for Permafrost (DOI/GTN-P). In addition to presenting data, this report also describes monitoring, data collection, and quality-control methods. The array of 16 monitoring stations spans lat 68.5°N. to 70.5°N. and long 142.5°W. to 161°W., an area of approximately 150,000 square kilometers. Climate summaries are presented along with quality-controlled data. Data collection is ongoing and includes the following climate- and permafrost-related variables: air temperature, wind speed and direction, ground temperature, soil moisture, snow depth, rainfall totals, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2018

DOI/GTN-P climate and active-layer data acquired in the National Petroleum Reserve-Alaska and the Arctic National Wildlife Refuge, 1998-2019

This report provides data collected by the climate monitoring array of the U.S. Department of the Interior on Federal lands in Arctic Alaska over the period August 1998 to July 2019; this array is part of the Global Terrestrial Network for Permafrost (DOI/GTN-P). In addition to presenting data, this report also describes monitoring, data collection, and quality-control methods. The array of 16 monitoring stations spans lat 68.5°N. to 70.5°N. and long 142.5°W. to 161°W., an area of approximately 150,000 square kilometers. Climate summaries are presented along with quality-controlled data. Data collection is ongoing and includes the following climate- and permafrost-related variables: air temperature, wind speed and direction, ground temperature, soil moisture, snow depth, rainfall totals, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2014

DOI/GTN-P climate and active-layer data acquired in the National Petroleum Reserve: Alaska and the Arctic National Wildlife Refuge, 1998-2011

This report provides data collected by the climate monitoring array of the U.S. Department of the Interior on Federal lands in Arctic Alaska over the period August 1998 to July 2011; this array is part of the Global Terrestrial Network for Permafrost, (DOI/GTN-P). In addition to presenting data, this report also describes monitoring, data collection, and quality-control methodology. This array of 16 monitoring stations spans lat 68.5°N. to 70.5°N. and long 142.5°W. to 161°W., an area of approximately 150,000 square kilometers. Climate summaries are presented along with quality-controlled data. Data collection is ongoing and includes the following climate- and permafrost-related variables: air temperature, wind speed and direction, ground temperature and soil moisture, snow depth, rainfall, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2014

DOI/GTN-P climate and active-layer data acquired in the National Petroleum Reserve-Alaska and the Arctic National Wildlife Refuge

This report provides data collected by the climate monitoring array of the U.S. Department of the Interior on Federal lands in Arctic Alaska over the period August 1998 to July 2013; this array is part of the Global Terrestrial Network for Permafrost, (DOI/GTN-P). In addition to presenting data, this report also describes monitoring, data collection, and quality-control methods. This array of 16 monitoring stations spans lat 68.5°N. to 70.5°N. and long 142.5°W. to 161°W., an area of approximately 150,000 square kilometers. Climate summaries are presented along with quality-controlled data. Data collection is ongoing and includes the following climate- and permafrost-related variables: air temperature, wind speed and direction, ground temperature, soil moisture, snow depth, rainfall totals, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2016

DOI/GTN-P Climate and active-layer data acquired in the National Petroleum Reserve–Alaska and the Arctic National Wildlife Refuge, 1998–2014

This report provides data collected by the climate monitoring array of the U.S. Department of the Interior on Federal lands in Arctic Alaska over the period August 1998 to July 2014; this array is part of the Global Terrestrial Network for Permafrost (DOI/GTN-P). In addition to presenting data, this report also describes monitoring, data collection, and quality-control methods. The array of 16 monitoring stations spans lat 68.5°N. to 70.5°N. and long 142.5°W. to 161°W., an area of approximately 150,000 square kilometers. Climate summaries are presented along with quality-controlled data. Data collection is ongoing and includes the following climate- and permafrost-related variables: air temperature, wind speed and direction, ground temperature, soil moisture, snow depth, rainfall totals, up- and downwelling shortwave radiation, and atmospheric pressure. These data were collected by the U.S. Geological Survey in close collaboration with the Bureau of Land Management and the U.S. Fish and Wildlife Service.

Alaska↗
USGS2000

The Sun and climate

Many geologic records of climatic and environmental change based on various proxy variables exhibit distinct cyclicities that have been attributed to extraterrestrial forcing. The best known of these are the changes in Earth’s orbital geometry called Milankovitch Cycles, with periodicities of tens to hundreds of thousands of years. However, many cycles seem to have subMilankovitch periodicities, commonly on decadal and centennial scales, similar to those of known solar cycles. A direct connection between solar irradiance (solar constant) and weather and climate has been suggested for more than 100 years but generally rejected by most scientists, who assume that the effect of solar variations would be small. However, recent satellite radiometer measurements and modeling studies indicate that small changes in total solar irradiance could produce global temperature changes of the magnitude suggested for climatic events such as the Little Ice Age (A.D. 1550–1700).

Fact Sheet↗
USGS2008

Prehistoric Packrats Piled Up Clues to Climate Change

Scientists from the U.S. Geological Survey and Northern Arizona University studying climate change in the Southwestern United States are getting a helping hand?or would that be paw??from prehistoric packrats. By hoarding parts of animals and plants, including seeds and leaves, in garbage piles or ?middens,? these bushy-tailed rodents preserved crucial ecological and environmental information about the past. From these middens, scientists are able to reconstruct plant communities and natural systems from as long ago as 50,000 years. The contents of middens allow scientists to understand how ecosystems responded to rapid, large-scale climate changes of the past. The insights gained from midden research could offer clues to future changes driven by rapid climate shifts.

Fact Sheet↗
USGS2009

Fifty-year record of glacier change reveals shifting climate in the Pacific Northwest and Alaska, USA

Fifty years of U.S. Geological Survey (USGS) research on glacier change shows recent dramatic shrinkage of glaciers in three climatic regions of the United States. These long periods of record provide clues to the climate shifts that may be driving glacier change. The USGS Benchmark Glacier Program began in 1957 as a result of research efforts during the International Geophysical Year (Meier and others, 1971). Annual data collection occurs at three glaciers that represent three climatic regions in the United States: South Cascade Glacier in the Cascade Mountains of Washington State; Wolverine Glacier on the Kenai Peninsula near Anchorage, Alaska; and Gulkana Glacier in the interior of Alaska (fig. 1).

Alaska, British Columbia, Washington↗
USGS2010

Studies of Climate Change in the Yukon River Basin: Connecting Community and Science Through a Unique Partnership

An exciting new partnership between the U.S. Geological Survey (USGS) and the Yukon River Inter-Tribal Watershed Council (YRITWC) is yielding critical data for the assessment of climate change effects in the Yukon River Basin. The foundation of this partnership is a shared interest in the current and future water quality of the Yukon River and its relation to climate. The USGS began a landmark study of the Yukon River and its major tributaries in 2000. A key objective of this study is to establish a baseline dataset of water quality, which will serve as an important frame of reference to assess future changes in the basin that may result from a warmer climate.

Fact Sheet↗
USGS2011

Upper Colorado River Basin Climate Effects Network

The Upper Colorado River Basin (UCRB) Climate Effects Network (CEN) is a science team established to provide information to assist land managers in future decision making processes by providing a better understanding of how future climate change, land use, invasive species, altered fire cycles, human systems, and the interactions among these factors will affect ecosystems and the services they provide to human communities. The goals of this group are to (1) identify science needs and provide tools to assist land managers in addressing these needs, (2) provide a Web site where users can access information pertinent to this region, and (3) provide managers technical assistance when needed. Answers to the team's working science questions are intended to address how interactions among climate change, land use, and management practices may affect key aspects of water availability, ecosystem changes, and societal needs within the UCRB.

Fact Sheet↗
USGS2010

Quantifying effects of climate change on the snowmelt-dominated groundwater resources of northern New England

Recent U.S. Geological Survey (USGS) climate studies in New England have shown substantial evidence of hydrologic changes during the last 100 years, including trends toward earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies are being expanded to include investigation of trends in groundwater levels and fluctuations. Groundwater is an important drinking-water source throughout northern New England (Maine, New Hampshire, and Vermont). The USGS is currently investigating whether or not groundwater recharge from snowmelt and precipitation exhibits historical trends. In addition to trend-testing, groundwater resources also will be analyzed by relating groundwater-level changes to the large year-to-year variability in weather conditions. Introduction The USGS has documented many seasonal climate-related changes in the northeastern United States that have occurred during the last 30 to 150 years. These changes include earlier snowmelt runoff in the late winter and early spring, decreasing duration of ice on rivers and lakes, decreasing ratio of snowfall to total precipitation, and denser and thinner late-winter snowpack. All of these changes are consistent with warming winter and spring air temperatures (Dudley and Hodgkins, 2002; Hodgkins and others, 2002; Huntington and others, 2004; Hodgkins and others, 2005; Hodgkins and Dudley, 2006a; Hodgkins and Dudley, 2006b). Climate-model projections for the Northeast indicate air-temperature warming, earlier snowmelt runoff, increases in annual evaporation, and decreased low streamflows (Hayhoe and others, 2007). The contribution and timing of spring snowmelt to groundwater recharge is particularly important to groundwater resources in the northeastern United States where aquifers typically consist of thin sediments overlying crystalline bedrock with relatively little storage capacity (Mack, 2009). Following spring recharge, groundwater slowly flows into streams throughout the summer. This groundwater flow is a source of cool water during the summer and accounts for a large proportion of the streamflow during summer low-flow periods. Groundwater is an important drinking-water source in northern New England. Approximately 32 percent of public water suppliers draw water from groundwater sources in Vermont, New Hampshire, and Maine, and approximately 40 percent of the population derives its drinking water from private wells (Kenny and others, 2009). It is vital to understand changes that may be occurring to such an important resource for planning industrial and agricultural water uses and protecting drinking water.

Fact Sheet↗
USGS2011

Evidence of multidecadal climate variability in the Gulf of Mexico

The northern Gulf of Mexico coastal region is vulnerable to a variety of natural hazards, many of which are linked to climate and climate variability. Hurricanes, which are one such climate-related hazard, are a major recurring problem, and the active hurricane seasons of 2004 and 2005 raised interest in better understanding the controls and risks of hurricanes. Examination of historical records reveals intervals of alternating low and high hurricane activity that appear to be related to changes in average sea-surface temperature in the North Atlantic Ocean. Analyses of instrumental temperature records from the North Atlantic show decadal-scale oscillations of slightly higher versus slightly lower average temperature extending back in time for over 100 years. This oscillation is known as the Atlantic Multidecadal Oscillation (AMO).

Fact Sheet↗
USGS2011

A climate trend analysis of Sudan

Summer rains in western and southern Sudan have declined by 10-20 percent since the mid-1970s. Observed warming of more than 1 degree Celsius is equivalent to another 10-20 percent reduction in rainfall for crops. The warming and drying have impacted southern Darfur and areas around Juba. Rainfall declines west of Juba threaten southern Sudan's future food production prospects. In many cases, areas with changing climate are coincident with zones of substantial conflict, suggesting some degree of association; however, the contribution of climate change to these conflicts is not currently understood. Rapid population growth and the expansion of farming and pastoralism under a more variable climate regime could dramatically increase the number of at-risk people in Sudan over the next 20 years.

Fact Sheet↗
USGS2012

Climatic changes and effect on wild sheep habitat

Wild sheep are sensitive to environmental change and may be an effective indicator species of climate change in arctic and high mountain ecosystems. To understand the effects of climatic changes on Dall sheep habitat, U.S. Geological Survey scientists have been studying selected areas in Alaska since 2007. The research focus is on forage quality, nutrient levels, and changes resulting from warming or cooling climate trends. Preliminary results indicate significant changes in Dall sheep diet accompanying vegetation changes and upslope retreat of glaciers.

Alaska↗
USGS2014

Landsat Surface Reflectance Climate Data Records

Landsat Surface Reflectance Climate Data Records (CDRs) are high level Landsat data products that support land surface change studies. Climate Data Records, as defined by the National Research Council, are a time series of measurements with sufficient length, consistency, and continuity to identify climate variability and change. The U.S. Geological Survey (USGS) is using the valuable 40-year Landsat archive to create CDRs that can be used to document changes to Earth’s terrestrial environment.

Fact Sheet↗
USGS2015

Effects of projected climate (2011–50) on karst hydrology and species vulnerability—Edwards aquifer, south-central Texas, and Madison aquifer, western South Dakota

Karst aquifers—formed by the dissolution of soluble rocks such as limestone—are critical groundwater resources in North America, and karst springs, caves, and streams provide habitat for unique flora and fauna. Springflow and groundwater levels in karst terrane can change greatly over short time scales, and therefore are likely to respond rapidly to climate change. How might the biological communities and ecosystems associated with karst respond to climate change and accompanying changes in groundwater levels and springflow? Sites in two central U.S. regions—the Balcones Escarpment of south-central Texas and the Black Hills of western South Dakota (fig. 1)—were selected to study climate change and its potential effects on the local karst hydrology and ecosystem. The ecosystems associated with the Edwards aquifer (Balcones Escarpment region) and Madison aquifer (Black Hills region) support federally listed endangered and threatened species and numerous State-listed species of concern, including amphibians, birds, insects, and plants. Full results are provided in Stamm and others (2014), and are summarized in this fact sheet.

South Dakota, Texas↗
USGS2015

Climate change: evaluating your local and regional water resources

The BCM is a fine-scale hydrologic model that uses detailed maps of soils, geology, topography, and transient monthly or daily maps of potential evapotranspiration, air temperature, and precipitation to generate maps of recharge, runoff, snow pack, actual evapotranspiration, and climatic water deficit. With these comprehensive environmental inputs and experienced scientific analysis, the BCM provides resource managers with important hydrologic and ecologic understanding of a landscape or basin at hillslope to regional scales. The model is calibrated using historical climate and streamflow data over the range of geologic materials specific to an area. Once calibrated, the model is used to translate climate-change data into hydrologic responses for a defined landscape, to provide managers an understanding of potential ecological risks and threats to water supplies and managed hydrologic systems. Although limited to estimates of unimpaired hydrologic conditions, estimates of impaired conditions, such as agricultural demand, diversions, or reservoir outflows can be incorporated into the calibration of the model to expand its utility. Additionally, the model can be linked to other models, such as groundwater-flow models (that is, MODFLOW) or the integrated hydrologic model (MF-FMP), to provide information about subsurface hydrologic processes. The model can be applied at a relatively small scale, but also can be applied to large-scale national and international river basins.

Fact Sheet↗