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At least 127 records · Page 7Linked to original sources
USGS2016

Climate adaption and post-fire restoration of a foundational perennial in cold desert: Insights from intraspecific variation in response to weather

1.The loss of foundational but fire-intolerant perennials such as sagebrush due to increases in fire size and frequency in semiarid regions has motivated efforts to restore them, often with mixed or even no success. Seeds of sagebrush Artemisia tridentata and related species must be moved considerable distances from seed source to planting sites, but such transfers have not been guided by an understanding of local climate adaptation. Initial seedling establishment and its response to weather are a key demographic bottleneck that likely varies among subspecies and populations of sagebrush. 2.We assessed differences in survival, growth, and physiological responses of sagebrush to weather among eleven seed sources that varied in subspecies, cytotype, and climates-of-origin over 18 months following outplanting. Diploid or polyploid populations of mountain, Wyoming, and basin big sagebrush ( A.tridentata ssp. vaseyana, A.tridentata ssp. wyomingensis, and A.tridentata ssp. tridentata , respectively) were planted onto five burned sites that normally support A.t.wyomingensis with some A.t.tridentata . 3.A.t.wyomingensis had the most growth and survival, and tetraploid populations had greater survival and height than diploids. Seasonal timing of mortality varied among the subspecies/cytotypes and was more closely related to minimum temperatures than water deficit. 4.Temperatures required to induce ice formation were up to 6°C more negative in 4n- A.t.tridentata and A.t.wyomingensis than other subspecies/cytotypes, indicating greater freezing avoidance. In contrast, freezing resistance of photosynthesis varied only 1°C among subspecies/cytotypes, being greatest in A.t.wyomingensis and least in the subspecies normally considered most cold-adapted, A.t.vaseyana . A large spectrum of reliance on freezing-avoidance vs. freezing-tolerance was observed and corresponded to differences in post-fire survivorship among subspecies/cytotypes. Differences in water deficit responses among subspecies/cytotypes were not as strong and did not relate to survival patterns. 5. Synthesis and applications. Low temperature responses are a key axis defining climate adaptation in young sagebrush seedlings and vary more with cytotype than with subspecies, which contrasts with the traditional emphases on (i) water limitations to explain establishment in these deserts, and (ii) subspecies in selecting restoration seedings. These important and novel insights on climate adaptation are critical for seed selection and parameterizing seed transfer zones, and were made possible by incorporating weather data with survival statistics. The survival/weather statistics used here could be applied to any restoration planting or seeding to help elucidate factors contributing to success and enable adaptive management.

Journal of Applied Ecology↗
USGS1988

National Research Program of the Water Resources Division, U.S. Geological Survey, fiscal year 1987

The National Research Program (NRP) of the U.S. Geological Survey's Water Resources Division (WRD) had its beginnings in the late 1950's when "core research" was added as a line item to the Congressional budget. Since that time, the NRP has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation's water resources. The knowledge gained and methods developed have great value to WRD's operational program. Results of the investigations conducted by the NRP are applicable not only to the solution of current water problems, but also to future issues, anticipated or unanticipated, that may affect the Nation's water resources.

Open-File Report↗
USGS1989

National Research Program of the Water Resources Division, U.S. Geological Survey: Fiscal Year 1988

The National Research Program (NRP) of the US Geological Survey 's Water Resources Division (WRD) had its beginnings in the late 1950 's when ' core research ' was added as a line item to the Congressional budget. Since that time, the NRP has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, ecology, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation 's water resources. The NRP is located principally in Reston, VA, Denver, CO, and Menlo Park , CA. The NRP is subdivided into six disciplines as follows: (1) Ecology; (2) Geomorphology and Sediment Transport; (3) Groundwater Chemistry; (4) Groundwater Hydrology; (5) Surface Water Chemistry; and (6) Surface Water Hydrology. The report provides current information about the NRP on an annual basis. Organized by the six research disciplines, the volume contains a summary of the problem, objective, approach, and progress for each project that was active during fiscal year 1988.

Open-File Report↗
USGS1989

National Research Program of the Water Resources Division, U. S. Geological Survey, Fiscal Year 1989

The National Research Program (NRP) of the U.S. Geological Survey's Water Resources Division (WRD) had its beginnings in the late 1950's when "core research" was added as a line item to the Congressional budget. Since that time, the NRP has grown to encompass a broad spectrum of scientific investigations. The sciences of hydrology, mathematics, chemistry, physics, ecology, biology, geology, and engineering are used to gain a fundamental understanding of the processes that affect the availability, movement, and quality of the Nation's water resources. The knowledge gained and methods developed have great value to WRD's operational program. Results of the investigations conducted by the NRP are applicable not only to the solution of current water problems but also to future issues, anticipated or unanticipated, that may affect the Nation's water resources.

Open-File Report↗
USGS2012

Structure, spectroscopy and dynamics of layered H2O and CO2 ices

Molecular dynamics simulations of structural, spectroscopic and dynamical properties of mixed water–carbon dioxide (H 2 O–CO 2 ) ices are discussed over temperature ranges relevant to atmospheric and astrophysical conditions. The simulations employ multipolar force fields to represent electrostatic interactions which are essential for spectroscopic and dynamical investigations. It is found that at the water/CO 2 interface the water surface acts as a template for the CO 2 component. The rotational reorientation times in both bulk phases agree well with experimental observations. A pronounced temperature effect on the CO 2 reorientation time is observed between 100 K and 200 K. At the interface, water reorientation times are nearly twice as long compared to water in the bulk. The spectroscopy of such ices is rich in the far-infrared region of the spectrum and can be related to translational and rotational modes. Furthermore, spectroscopic signatures mediated across the water/CO 2 interface are found in this frequency range (around 440 cm −1 ). These results will be particularly important for new airborne experiments such as planned for SOFIA.

Physical Chemistry Chemical Physics↗
USGS2000

Detection of crystalline hematite mineralization on Mars by the Thermal Emission Spectrometer: evidence for near-surface water

The Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor (MGS) mission has discovered a remarkable accumulation of crystalline hematite (α-Fe 2 O 3 ) that covers an area with very sharp boundaries approximately 350 by 350–750 km in size centered near 2°S latitude between 0° and 5°W longitude (Sinus Meridiani). Crystalline hematite is uniquely identified by the presence of fundamental vibrational absorption features centered near 300, 450, and >525 cm −1 and by the absence of silicate fundamentals in the 1000 cm −1 region. Spectral features resulting from atmospheric CO 2 , dust, and water ice were removed using a radiative transfer model. The spectral properties unique to Sinus Meridiani were emphasized by removing the average spectrum of the surrounding region. The depth and shape of the hematite fundamental bands show that the hematite is crystalline and relatively coarse grained (>5–10 μm). Diameters up to and greater than hundreds of micrometers are permitted within the instrumental noise and natural variability of hematite spectra. Hematite particles <5–10 μm in diameter (as either unpacked or hard-packed powders) fail to match the TES spectra. The spectrally derived areal abundance of hematite varies with particle size from ∼10% (>30 μm diameter) to 40–60% (10 μm diameter). The hematite in Sinus Meridiani is thus distinct from the fine-grained (diameter <5–10 μm), red, crystalline hematite considered, on the basis of visible, near-IR data, to be a minor spectral component in Martian bright regions like Olympus-Amazonis. Sinus Meridiani hematite is closely associated with a smooth, layered, friable surface that is interpreted to be sedimentary in origin. This material may be the uppermost surface in the region, indicating that it might be a late stage sedimentary unit or a layered portion of the heavily cratered plains units. We consider five possible mechanisms for the formation of coarse-grained, crystalline hematite. These processes fall into two classes depending on whether they require a significant amount of near-surface water: the first is chemical precipitation that includes origin by (1) precipitation from standing, oxygenated, Fe-rich water (oxide iron formations), (2) precipitation from Fe-rich hydrothermal fluids, (3) low-temperature dissolution and precipitation through mobile ground water leaching, and (4) formation of surface coatings, and the second is thermal oxidation of magnetite-rich lavas. Weathering and alteration processes, which produce nanophase and red hematite, are not consistent with the coarse, crystalline hematite observed in Sinus Meridiani. We prefer chemical precipitation models and favor precipitation from Fe-rich water on the basis of the probable association with sedimentary materials, large geographic size, distance from a regional heat source, and lack of evidence for extensive groundwater processes elsewhere on Mars. The TES results thus provide mineralogic evidence for probable large-scale water interactions. The Sinus Meridiani region may be an ideal candidate for future landed missions searching for biotic and prebiotic environments, and the physical characteristics of this site satisfy all of the engineering requirements for the missions currently planned.

Journal of Geophysical Research E: Planets↗
USGS2010

Seasonal groundwater contribution to crop-water use assessed with lysimeter observations and model simulations

Groundwater evaporation can play an important role in crop-water use where the water table is shallow. Lysimeters are often used to quantify the groundwater evaporation contribution influenced by a broad range of environmental factors. However, it is difficult for such field facilities, which are operated under limited conditions within limited time, to capture the whole spectrum of capillary upflow with regard to the inter-seasonal variability of climate, especially rainfall. Therefore, in this work, the method of combining lysimeter and numerical experiments was implemented to investigate seasonal groundwater contribution to crop-water use. Groundwater evaporation experiments were conducted through a weighing lysimeter at an agricultural experiment station located within an irrigation district in the lower Yellow River Basin for two winter wheat growth seasons. A HYDRUS-1D model was first calibrated and validated with weighing lysimeter data, and then was employed to perform scenario simulations of groundwater evaporation under different depths to water table (DTW) and water input (rainfall plus irrigation) driven by long term meteorological data. The scenario simulations revealed that the seasonally averaged groundwater evaporation amount was linearly correlated to water input for different values of DTW. The linear regression could explain more than 70% of the variability. The seasonally averaged ratio of the groundwater contribution to crop-water use varied with the seasonal water input and DTW. The ratio reached as high as 75% in the case of DTW=1.0. m and no irrigation, and as low as 3% in the case of DTW=3.0. m and three irrigation applications. The results also revealed that the ratio of seasonal groundwater evaporation to potential evapotranspiration could be fitted to an exponential function of the DTW that may be applied to estimate seasonal groundwater evaporation. In this case study of multilayered soil profile, the depth at which groundwater may evaporate at potential rate was 0.60-0.65. m, and the extinction depth of groundwater evaporation was approximately 3.8. m. ?? 2010 Elsevier B.V.

Journal of Hydrology↗
USGS2022

Characterization of arsenic species in microbial mats from an inactive gold mine

Filamentous cyanobacterial mats and Fe oxyhydroxide-rich bacterial mats collected near an inactive gold mine in California are enriched in arsenic (As) approximately 1000-fold relative to the waters in contact with them. The predominant organism in the cyanobacterial mat could not be identified using morphological characteristics, but the unique morphology of the sheath-forming β protobacterium Leptothrix ochracea was used to identify this species in Fe oxyhydroxide mat samples from several sites near the gold mine. Leptothrix sheaths commonly exceed 10 μm in length and have an average diameter of 1 μm . The Fe-oxyhydroxide mats are dominated by L. ochracea sheaths, but use of fluorescently tagged genetic stains reveals the presence of sheathless bacteria that presumably also promote the formation of Fe oxyhydroxide. X-ray absorption fine structure (XAFS) spectroscopy was used to identify As species in these microbial mats. Mat-associated As is predominantly As(V), even when As(III) is the primary dissolved species in contact with the mats. The species of As(V) associated with the cyanobacterial mat could not be conclusively identified; however, it is not associated with Fe oxyhydroxide or other minerals, based on comparison to XAFS spectra of As adsorbed to various substrates. In addition, the cyanobacterial mat XAFS spectrum is different from that of aqueous As(V), suggesting that As(V) in the mat lacks some or all of the coordinating water molecules present in aqueous solution. We hypothesize that As is associated with the exopolysaccharide (EPS) matrix secreted by the cyanobacteria. In Leptothrix -dominated Fe-oxyhydroxide bacterial mats, XAFS analysis clearly indicates that As(V) is associated with the Fe oxyhydroxide as an adsorbed and/or coprecipitated complex.

California↗
USGS2007

Climate variability controls on unsaturated water and chemical movement, High Plains aquifer, USA

Responses in the vadose zone and groundwater to interannual, interdecadal, and multidecadal climate variability have important implications for groundwater resource sustainability, yet they are poorly documented and not well understood in most aquifers of the USA. This investigation systematically examines the role of interannual to multidecadal climate variability on groundwater levels, deep infiltration (3–23 m) events, and downward displacement (>1 m) of chloride and nitrate reservoirs in thick (15–50 m) vadose zones across the regionally extensive High Plains aquifer. Such vadose zone responses are unexpected across much of the aquifer given a priori that unsaturated total-potential profiles indicate upward water movement from the water table toward the root zone, mean annual potential evapotranspiration exceeds mean annual precipitation, and millennia-scale evapoconcentration results in substantial vadose zone chloride and nitrate reservoirs. Using singular spectrum analysis (SSA) to reconstruct precipitation and groundwater level time-series components, variability was identified in all time series as partially coincident with known climate cycles, such as the Pacific Decadal Oscillation (PDO) (10–25 yr) and the El Niño/Southern Oscillation (ENSO) (2–6 yr). Using these lag-correlated hydrologic time series, a new method is demonstrated to estimate climate-varying unsaturated water flux. The results suggest the importance of interannual to interdecadal climate variability on water-flux estimation in thick vadose zones and provide better understanding of the climate-induced transients responsible for the observed deep infiltration and chemical-mobilization events. Based on these results, we discuss implications for climate-related sustainability of the High Plains aquifer.

Vadose Zone Journal↗
USGS1973

Fluorescent spectroscopy, a technique for characterizing surface films

A relationship is established between fluorescent spectra obtained by using a light path through the liquid solution and the fluorescent spectra obtained by a direct reading of surface reflection (remote sensing). A brief review of quantum fundamentals provides the necessary information to conclude that "see-through" and reflectance spectra are identical in wavelength response. Many floating films contain fluorescent materials; thus fluorescent spectroscopic techniques were used to obtain the fluorescent spectra of lube oil, crude oil, and lignosulfonie acid in an effort to detect, identify, and quantify these representative fluorescent materials in water solutions. For each material tested the emission maximum was established. The emission maximum was then held constant while the absorption spectrum was recorded and the absorption maximum established. The complete spectral curves are presented.

Journal of Research of the U.S. Geological Survey↗
USGS2014

Seismic profile analysis of sediment deposits in Brownlee and Hells Canyon Reservoirs near Cambridge, Idaho

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center, in cooperation with the USGS Idaho Water Science Center and the Idaho Power Company, collected high-resolution seismic reflection data in the Brownlee and Hells Canyon Reservoirs, in March of 2013.These reservoirs are located along the Snake River, and were constructed in 1958 (Brownlee) and 1967 (Hells Canyon). The purpose of the survey was to gain a better understanding of sediment accumulation within the reservoirs since their construction. The chirp system used in the survey was an EdgeTech Geo-Star Full Spectrum Sub-Bottom (FSSB) system coupled with an SB-424 towfish with a frequency range of 4 to 24 kHz. Approximately 325 kilometers of chirp data were collected, with water depths ranging from 0-90 meters. These reservoirs are characterized by very steep rock valley walls, very low flow rates, and minimal sediment input into the system. Sediments deposited in the reservoirs are characterized as highly fluid clays. Since the acoustic signal was not able to penetrate the rock substrate, only the thin veneer of these recent deposits were imaged. Results from the seismic survey indicate that throughout both of the Brownlee and Hells Canyon reservoirs the accumulation of sediments ranged from 0 to 2.5 m, with an average of 0.5 m. Areas of above average sediment accumulation may be related to lower slope, longer flooding history, and proximity to fluvial sources.

Idaho;Oregon↗
USGS2008

Utilizing spectral analysis of coastal discharge computed by a numerical model to determine boundary influence

In the present study, a spectral analysis was applied to field data and a numerical model of southeastern Everglades and northeastern Florida Bay that involved computing and comparing the power spectrum of simulated and measured flows at the primary coastal outflow creek. Four dominant power frequencies, corresponding to the S1, S2, M2, and 01 tidal periods, were apparent in the measured outflows. The model seemed to reproduce the magnitudes of the S1 and S2 components better than those of the M2 and 01 components. To determine the cause of the relatively poor representation of the M2 and 01 components, we created a steady-base version of the model by setting the time-varying forcing functions - rainfall, evapotranspiration, wind, and inland and tidal boundary conditions - to averaged values. The steady-base model was then modified to produce multiple simulations with only one time-varying forcing function for each model run. These experimental simulations approximated the individual effects of each forcing function on the system. The spectral analysis of the experimental simulations indicated that temporal fluctuations in rainfall, evapotranspiration, and inland water level and discharge boundaries have negligible effects on coastal creek flow fluctuations with periods of less than 48 hours. The tidal boundary seems to be the only forcing function inducing the M2 and 01 frequency flow fluctuations in the creek. An analytical formulation was developed, relating the errors induced by the tidal water-level gauge resolution to the errors in the simulated discharge fluctuations at the coastal creek. This formulation yielded a discharge-fluctuation error similar in magnitude to the errors observed when comparing the spectrum of the simulated and measured discharge. The dominant source of error in the simulation of discharge fluctuation magnitude is most likely the resolution of the water-level gauges used to create the model boundary.

Journal of Coastal Research↗
USGS2008

Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua

Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active volcanoes in Central America. The soil temperatures were measured in a low-temperature fumarole field located 3.5 km down the flanks of the volcano. Analysis of these time series reveals that they respond extremely rapidly, on a time scale of minutes, to changes in volcanic activity also manifested at the summit vent. These rapid temperature changes are caused by increased flow of water vapor through flank fumaroles during volcanism. The soil temperature response, ~5 °C, is repetitive and complex, with as many as 13 pulses during a single volcanic episode. Analysis of the frequency spectrum of these temperature time series shows that these anomalies are characterized by broad frequency content during volcanic activity. They are thus easily distinguished from seasonal trends, diurnal variations, or individual rainfall events, which triggered rapid transient increases in temperature during 5% of events. We suggest that the mechanism responsible for the distinctive temperature signals is rapid change in pore pressure in response to magmatism, a response that can be enhanced by meteoric water infiltration. Monitoring of distal fumaroles can therefore provide insight into coupled volcanic-hydrologic-meteorologic systems, and has potential as an inexpensive monitoring tool.

Masaya Volcano↗
USGS2024

Spatial and temporal variability of movements among sympatric salmonids in an unfragmented inland watershed

Objective Our aim was to determine the movement patterns of three abundant salmonids—Brown Trout Salmo trutta , Mountain Whitefish Prosopium williamsoni , and Rainbow Trout Oncorhynchus mykiss —in the Smith River watershed of Montana. Methods We tagged 7172 fish with passive integrated transponder (PIT) tags, monitored their movements past 15 stationary PIT arrays over 4 years, and located tagged fish between arrays by conducting mobile surveys. Result Movement patterns varied seasonally, among species, and among locations. Movement was greatest in the middle portion of the watershed, which included a pristine main‐stem canyon and lower reaches of major tributaries. Fish rarely left the canyon, but movement into the canyon from other regions was common. Mountain Whitefish were most likely to move, and Brown Trout were least likely to move. Most fish travelled less than 10 km, but some fish travelled over 100 km. Distinct movement patterns were not evident; rather, a continuous spectrum of movement behaviors was apparent. Movements by Mountain Whitefish and Rainbow Trout increased during their spawning periods. Movements peaked when mean daily water temperatures were between 11.3 and 17.1°C. Conclusion Movements were diverse and probably contributed to metapopulation dynamics, population resiliency, and species diversity. Fish movements along stream networks connect populations across diverse landscapes, and therefore, protecting and restoring stream connectivity along inland streams such as the Smith River is critical to maintaining productive fish assemblages.

Montana↗
USGS2024

Large eddy simulation of cross-shore hydrodynamics under random waves in the inner surf and swash zones

A 3D large eddy simulation coupled with a free surface tracking scheme was used to simulate cross-shore hydrodynamics as observed in a large wave flume experiment. The primary objective was to enhance the understanding of wave-backwash interactions and the implications for observed morphodynamics. Two simulation cases were carried out to elucidate key processes of wave-backwash interactions across two distinct stages: berm erosion and sandbar formation, during the early portion of a modeled storm. The major difference between the two cases was the bathymetry: one featuring a berm without a sandbar (Case I), and the other, featuring a sandbar without a berm (Case II) at similar water depth. Good agreement (overall Willmott's index of agreement greater than 0.8) between simulations and measured data in free surface elevation, wave spectrum, and flow velocities validated the model skill. The findings indicated that the bottom shear stress, represented by the Shields parameter, was significant in both cases, potentially contributing substantial sediment transport. Notably, the occurrence of intense wave-backwash interactions were more frequent in the absence of a sandbar. These intense wave-backwash interactions resulted in a pronounced horizontal pressure gradient, quantified by high Sleath parameters, exceeding the criteria for momentary bed failure. Additionally, a more vigorous turbulence-bed interaction, characterized by near-bed turbulent kinetic energy, was observed in the case lacking a sandbar, potentially augmenting sediment suspension. These insights are pivotal in understanding the mechanisms underlying berm erosion and how sandbar formation serves to protect further beach erosion.

JGR Oceans↗
USGS2018

Presentation of the Dana Medal of the Mineralogical Society of America for 2017 to Thomas W. Sisson

I have the pleasure of introducing Thomas W. Sisson, the Mineralogical Society of America Dana Medalist for 2017. Tom is known for his scientific rigor and landmark publications that have contributed to a diverse spectrum of fields closely tied to the mineralogical sciences. He is particularly recognized for his work on magma differentiation and the role of water in subduction-related magmatism. Beginning with his Ph.D. research with Tim Grove, Tom's early papers showcase difficult high-temperature experiments on hydrous basalt and magmatic processes recorded by the Sierra Nevada batholith. This landmark work was soon followed by ion microprobe measurements of dissolved water concentrations in melt inclusions from a range of arc basalts and by infrared spectrometric determinations of dissolved H2O and CO2 concentrations in unusually primitive arc basalt.

American Mineralogist↗
USGS2002

User's guide to Model Viewer, a program for three-dimensional visualization of ground-water model results

Model Viewer is a computer program that displays the results of three-dimensional groundwater models. Scalar data (such as hydraulic head or solute concentration) may be displayed as a solid or a set of isosurfaces, using a red-to-blue color spectrum to represent a range of scalar values. Vector data (such as velocity or specific discharge) are represented by lines oriented to the vector direction and scaled to the vector magnitude. Model Viewer can also display pathlines, cells or nodes that represent model features such as streams and wells, and auxiliary graphic objects such as grid lines and coordinate axes. Users may crop the model grid in different orientations to examine the interior structure of the data. For transient simulations, Model Viewer can animate the time evolution of the simulated quantities. The current version (1.0) of Model Viewer runs on Microsoft Windows 95, 98, NT and 2000 operating systems, and supports the following models: MODFLOW-2000, MODFLOW-2000 with the Ground-Water Transport Process, MODFLOW-96, MOC3D (Version 3.5), MODPATH, MT3DMS, and SUTRA (Version 2D3D.1). Model Viewer is designed to directly read input and output files from these models, thus minimizing the need for additional postprocessing. This report provides an overview of Model Viewer. Complete instructions on how to use the software are provided in the on-line help pages.

Open-File Report↗
USGS1968

Infrared survey of the Pisgah Crater area, San Bernardino County, California - a geologic interpretation

The infrared survey of the Pisgah Crater Area, San Bernardino County, California was primarily undertaken to establish parameters by which rock types, structures, and textures peculiar to this locale could be recognized or differentiated. A secondary purpose was to provide an adequate evaluation and calibration of airborne and ground-based instruments used in the survey. Pisgah Crater and its vicinity was chosen as one of the fundamental test sites for the NASA remote sensing program because of its relatively fresh basaltic flows and pyroclastics. Its typical exposure of basalt also made it a possible lunar analogue. A fundamental test site for the purpose of the program is defined as a readily accessible area for which the topography, geology, hydrology, soils, vegetation and other features are relatively well known. All remote sensor instrument teams, i.e. infrared, radar, microwave, and photography, were obligated to use the fundamental test sites for instrument evaluation and to establish terrain identification procedures. Pisgah Crater, nearby Sunshine Cone, and their associated lava flows are in the southern Mojave Desert about 40 miles east-southeast of Barstow, California. (See fig. 1.) U. S. Highway 66 skirts .the northern part of the area and provides access via asphalt-paved and dirt roads to the Crater and to the perimeters of the flows. Pisgah Crater, which is a pumiceous cone, is owned and occasionally quarried by the Atchison, Topeka and Santa Fe Railroad. The remaining part of the area to the south is within the boundary of the Marine Corps Base, Twentynine Palms, California and is currently being used as a gunnery, and bombing range. The proximate area to east, west, and north of Pisgah Crater is public domain. Originally, an area totaling 10 square miles was outlined for detailed study. (See plate 1.) This included an 8 mile long strip extending south- east from and including Pisgah Crater to Lavic Dry Lake, and a 2 mile strip aligned to include a portion of the Sunshine lava flow and the dry lake. Additional aerial infrared imagery of the Sunshine and Pisgah flows along the Pisgah fault proved so interesting and informative that this area is included in the discussion. Infrared surveys were flown February ii through 13, 1965 and August 5 and 9, 1966. The initial survey was flown by the NASA personnel aboard the NASA 926 Convair 240 aircraft. Because of technical problems with the infrared scanners (4.5-5.5 and 8-14 micron bands) and with certain ground instruments, most of the imagery and ground temperature data obtained during the initial survey period was of little value. However, excellent infrared imagery in the 8-14 micron (?) region of the spectrum was acquired by the Geological Survey during the August 1966 survey. The scanner was mounted in a Beech D-18 aircraft provided by the Survey's Water Resources Division. Likewise, more reliable ground data was obtained at this time owing to improved instrumentation and technique. Ground data were taken by Geological Survey personnel including W. A. Fischer, J. D. Friedman, W. R. Hemphill, D. L. Daniels, G. R. Boynton, Po W. Philbin and the author. C. R. Fross operated the infrared scanner during the August, 1966 survey and R. M. Turner was-responsible for photo processing of the infrared imagery. Their assistance is gratefully acknowledged.

Open-File Report↗