39. CENTRAL SECTION, TELEPHOTO VIEW FROM AREA OF PORTER PLOT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. CENTRAL SECTION, TELEPHOTO VIEW FROM AREA OF PORTER PLOT LOOKING EAST TO WEST (NOTE SAME OBELISK CAPPED BY A FUNERAL URN SEEN IN HABS No. PA-1811-38) - Laurel Hill Cemetery, 3822 Ridge Avenue, Philadelphia, Philadelphia County, PA

Trace metal characterization of aerosol particles and cloud water during HCCT 2010

NASA Astrophysics Data System (ADS)

Fomba, K. W.; van Pinxteren, D.; Müller, K.; Iinuma, Y.; Lee, T.; Collett, J. L., Jr.; Herrmann, H.

2015-08-01

Trace metal characterization of bulk and size-resolved aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign. Cloud water was collected at the top of Mt. Schmücke while aerosol samples were collected at two stations upwind and downwind of Mt. Schmücke. Fourteen trace metals including Ti, V, Fe, Mn, Co, Zn, Ni, Cu, As, Sr, Rb, Pb, Cr, and Se were investigated during four full cloud events (FCEs) that fulfilled the conditions of a continuous air mass flow through the three stations. Aerosol particle trace metal concentrations were found to be lower than those observed in the same region during previous field experiments but were within a similar range to those observed in other rural regions in Europe. Fe and Zn were the most abundant elements with concentration ranges of 0.2-111.6 and 1.1-32.1 ng m-3, respectively. Fe, Mn, and Ti were mainly found in coarse mode aerosols while Zn, Pb, and As were mostly found in the fine mode. Correlation and enrichment factor analysis of trace metals revealed that trace metals such as Ti and Rb were mostly of crustal origin while trace metals such as Zn, Pb, As, Cr, Ni, V, and Cu were of anthropogenic origin. Trace metals such as Fe and Mn were of mixed origins including crustal and combustion sources. Trace metal cloud water concentration decreased from Ti, Mn, Cr, to Co with average concentrations of 9.18, 5.59, 5.54, and 0.46 μg L-1, respectively. A non-uniform distribution of soluble Fe, Cu, and Mn was observed across the cloud drop sizes. Soluble Fe and Cu were found mainly in cloud droplets with diameters between 16 and 22 μm, while Mn was found mostly in larger drops greater than 22 μm. Fe(III) was the main form of soluble Fe especially in the small and larger drops with concentrations ranging from 2.2 to 37.1 μg L-1. In contrast to other studies, Fe(II) was observed mainly in the evening hours, implying its presence was not directly related to photochemical processes. Aerosol-cloud interaction did not lead to a marked increase in soluble trace metal concentrations; rather it led to differences in the chemical composition of the aerosol due to preferential loss of aerosol particles through physical processes including cloud drop deposition to vegetative surfaces.

Trace metal characterization of aerosol particles and cloud water during HCCT 2010

NASA Astrophysics Data System (ADS)

Fomba, K. W.; van Pinxteren, D.; Müller, K.; Iinuma, Y.; Lee, T.; Collet, J., Jr.; Herrmann, H.

2015-04-01

Trace metal characterization of bulk and size resolved aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign. Cloud water was collected at the top of Mt. Schmücke while aerosol samples were collected at two stations upwind and downwind of Mt. Schmücke. Fourteen trace metals including Ti, V, Fe, Mn, Co, Zn, Ni, Cu, As, Sr, Rb, Pb, Cr, and Se were investigated during four full cloud events (FCE) that fulfilled the conditions of a continuous air mass flow through the three stations. Aerosol particle trace metal concentrations were found to be lower than those observed in the same region during previous field experiments but were within a similar range to those observed in other rural regions in Europe. Fe and Zn were the most abundant elements with concentration ranges of 0.2-111.6 and 1.1-32.1 ng m-3, respectively. Fe, Mn and Ti were mainly found in coarse mode aerosols while Zn, Pb and As were mostly found in the fine mode. Correlation and enrichment factor analysis of trace metals revealed that trace metals such as Ti and Rb were mostly of crustal origin while trace metals such as Zn, Pb, As, Cr, Ni, V, and Cu were of anthropogenic origin. Trace metals such as Fe, Mn, were of mixed origins including crustal and combustion sources. Trace metal cloud water concentration decreased from Ti, Mn, Cr, to Co with average concentrations of 9.18, 5.59, 5.54, and 0.46 μg L-1, respectively. A non-uniform distribution of soluble Fe, Cu and Mn was observed across the cloud drop sizes. Soluble Fe and Cu were found mainly in cloud droplets with diameters between 16 and 22 μm while Mn was found mostly in larger drops greater than 22 μm. Fe (III) was the main form of soluble Fe especially in the small and larger drops with concentrations ranging from 2.2 to 37.1 μg L-1. In contrast to other studies, Fe (II) was observed mainly in the evening hours, implying its presence was not directly related to photochemical processes. Aerosol cloud interaction did not lead to a mark increase in soluble trace metal concentrations, but led to differences in the chemical composition of the aerosol due to preferential loss of aerosol particles through physical processes including cloud drop deposition to vegetative surfaces.

Elevation Measurement Profile of Mars

NASA Technical Reports Server (NTRS)

1999-01-01

The elevation measurements were collected by the Mars Orbiter Laser Altimeter (MOLA) aboard Global Surveyor during the spring and summer of 1998, as the spacecraft orbited Mars in an interim elliptical orbit. MOLA sends laser pulses toward the planet and measures the precise amount of time before the reflected signals are received back at the instrument. From this data, scientists can infer surface and cloud heights.

During its mapping of the north polar cap, the MOLA instrument also made the first direct measurement of cloud heights on the red planet. Reflections from the atmosphere were obtained at altitudes from just above the surface to more than nine miles (approximately 15 kilometers) on about 80 percent of the laser profiles. Most clouds were observed at high latitudes, at the boundary of the ice cap and surrounding terrain.

Clouds observed over the polar cap are likely composed of carbon dioxide that condenses out of the atmosphere during northern hemisphere winter. Many clouds exhibit dynamic structure probably caused by winds interacting with surface topography, much as occurs on Earth when winds collide with mountains to produce turbulence.

The principal investigator for MOLA is Dr. David E. Smith of Goddard. The MOLA instrument was designed and built by the Laser Remote Sensing Branch of Laboratory for Terrestrial Physics at Goddard. The Mars Global Surveyor Mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for the NASA Office of Space Science.

Polar Winds

NASA Image and Video Library

2018-04-05

This VIS image shows 'streamers' of clouds created by katabatic winds at the north polar cap. Katabatic winds are created by cold air sinking at the pole and then speeding along the ice surface towards the edge of the polar cap. When the winds enter troughs the wind regime changes from laminar flow to choatic and clouds of ice particles and/or dust are visible. This wind activity peaks at the start of northern hemisphere summer. Orbit Number: 53942 Latitude: 86.8433 Longitude: 99.3149 Instrument: VIS Captured: 2014-02-10 10:50 https://photojournal.jpl.nasa.gov/catalog/PIA22362

Impact of the CO2 and H2O clouds of the Martian polar hood on the polar energy balance

NASA Technical Reports Server (NTRS)

Forget, Francois; Pollack, James B.

1993-01-01

Clouds covering extensive areas above the martian polar caps have regularly been observed during the fall and winter seasons of each hemisphere. These 'polar hoods' are thought to be made of H2O and CO2. In particular, the very cold temperatures observed during the polar night by Viking and Mariner 9 around both poles have been identified as CO2 clouds and several models, including GCM, have indicated that the CO2 can condense in the atmosphere at all polar latitudes. Estimating the impact of the polar hood clouds on the energy balance of the polar regions is necessary to model the CO2 cycle and address puzzling problems like the polar caps assymetry. For example, by altering the thermal radiation emitted to space, CO2 clouds alter the amount of CO2 that condenses during the fall and winter season. The complete set of Viking IRTM data was analyzed to define the spatial and temporal properties of the polar hoods, and how their presence affects the energy radiated by the atmosphere/caps system to space was estimated. The IRTM observations provide good spatial and temporal converage of both polar regions during fall, winter, and spring, when a combination of the first and the second Viking year is used. Only the IRTM brightness temperatures at 11, 15, and 20 microns are reliable at martian polar temperatures. To recover the integrated thermal fluxes from the IRTM data, a simple model of the polar hood, thought to consist of 'warm' H2O clouds lying above colder and opaque CO2 clouds was developed. Such a model is based on the analysis of the IRIS spectra, and is consistent with the IRTM data used.

Health effects of acute exposure to air polllution. Part II: Healthy subjects exposed to cencentrated ambient particles

EPA Science Inventory

The purpose of this study was to assess the impact of short-term exposure to concentrated ambient particles (CAPs*) on lung function and on inflammatory parameters in blood and airways of healthy human subjects. Particles were concentrated from the ambient air in Chapel Hill, Nor...

The hemispherical asymmetry of the residual polar caps on Mars

NASA Technical Reports Server (NTRS)

Lindner, Bernhard Lee

1991-01-01

A model of the polar caps of Mars was created which allows: (1) for light penetration into the cap; (2) ice albedo to vary with age, latitude, hemisphere, dust content, and solar zenith angle; and (3) for diurnal variability. The model includes the radiative effects of clouds and dust, and heat transport as represented by a thermal wind. The model reproduces polar cap regression data very well, including the survival of CO2 frost at the south pole and reproduces the general trend in the Viking Lander pressure data.

Katabatic jumps in the Martian northern polar regions

NASA Astrophysics Data System (ADS)

Spiga, Aymeric; Smith, Isaac

2018-07-01

Martian polar regions host active regional wind circulations, such as the downslope katabatic winds which develop owing to near-surface radiative cooling and sloped topography. Many observations (stratigraphy from radar profiling, frost streaks, spectral analysis of ices) concur to show that aeolian processes play a key role in glacial processes in Martian polar regions. A spectacular manifestation of this resides in elongated clouds that forms within the polar spiral troughs, a series of geological depressions in Mars' polar caps. Here we report mesoscale atmospheric modeling in Martian polar regions making use of five nested domains operating a model downscaling from horizontal resolutions of twenty kilometers to 200 m in a typical polar trough. We show that strong katabatic jumps form at the bottom of polar troughs with an horizontal morphology and location similar to trough clouds, large vertical velocity (up to +3 m/s) and temperature perturbations (up to 20 K) propitious to cloud formation. This strongly suggests that trough clouds on Mars are caused by katabatic jumps forming within polar troughs. This phenomena is analogous to the terrestrial Loewe phenomena over Antarctica's slopes and coastlines, resulting in a distinctive "wall of snow" during katabatic events. Our mesoscale modeling results thereby suggest that trough clouds might be present manifestations of the ice migration processes that yielded the internal cap structure discovered by radar observations, as part of a "cyclic step" process. This has important implications for the stability and possible migration over geological timescales of water ice surface reservoirs-and, overall, for the evolution of Mars' polar caps over geological timescales.

The CAMEO barium release - E/parallel/ fields over the polar cap

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Miller, M. L.; Pongratz, M. B.; Smith, G. M.; Smith, L. L.; Mende, S. B.; Nath, N. R.

1981-01-01

Four successive thermite barium releases at an altitude of 965 km over polar cap invariant latitudes 84 to 76 deg near magnetic midnight were conducted from the orbiting second stage of the vehicle that launched Nimbus 7; the releases were made as part of the CAMEO (Chemically Active Material Ejected in Orbit) program. This was the first opportunity to observe the behavior of conventional barium release when conducted at orbital velocity in the near-earth magnetic field. The principal unexpected characteristic in the release dynamics was the high, 1.4 to 2.6 km/s, initial Ba(+) expansion velocity relative to an expected velocity of 0.9 km/s. Attention is also given to neutral cloud expansion, initial ion cloud expansion, convective motion, and the characteristics of field-aligned motion. The possibility of measuring parallel electric fields over the polar cap by observing perturbations in the motion of the visible ions is assessed.

A decision tool for selecting trench cap designs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paige, G.B.; Stone, J.J.; Lane, L.J.

1995-12-31

A computer based prototype decision support system (PDSS) is being developed to assist the risk manager in selecting an appropriate trench cap design for waste disposal sites. The selection of the {open_quote}best{close_quote} design among feasible alternatives requires consideration of multiple and often conflicting objectives. The methodology used in the selection process consists of: selecting and parameterizing decision variables using data, simulation models, or expert opinion; selecting feasible trench cap design alternatives; ordering the decision variables and ranking the design alternatives. The decision model is based on multi-objective decision theory and uses a unique approach to order the decision variables andmore » rank the design alternatives. Trench cap designs are evaluated based on federal regulations, hydrologic performance, cover stability and cost. Four trench cap designs, which were monitored for a four year period at Hill Air Force Base in Utah, are used to demonstrate the application of the PDSS and evaluate the results of the decision model. The results of the PDSS, using both data and simulations, illustrate the relative advantages of each of the cap designs and which cap is the {open_quotes}best{close_quotes} alternative for a given set of criteria and a particular importance order of those decision criteria.« less

Paleontology. A Curriculum and Activity Guide to Mammoth Cave National Park. [Grades] 1-12.

ERIC Educational Resources Information Center

National Park Service (Dept. of Interior), Washington, DC.

Mammoth Cave (Kentucky) was designated as a national park in 1941 because of its beautiful hills and valleys, scenic rivers, and the vast cave system located within its boundaries. Outstanding physiographic features include karst terrains, sandstone capped plateaus, and bluffs overlooking rivers and streams, which provide an unusually wide variety…

Simulating the Current Water Cycle with the NASA Ames Mars Global Climate Model

NASA Astrophysics Data System (ADS)

Kahre, M. A.; Haberle, R. M.; Hollingsworth, J. L.; Brecht, A. S.; Urata, R. A.; Montmessin, F.

2017-12-01

The water cycle is a critical component of the current Mars climate system, and it is now widely recognized that water ice clouds significantly affect the nature of the simulated water cycle. Two processes are key to implementing clouds in a Mars global climate model (GCM): the microphysical processes of formation and dissipation, and their radiative effects on atmospheric heating/cooling rates. Together, these processes alter the thermal structure, change the atmospheric dynamics, and regulate inter-hemispheric transport. We have made considerable progress using the NASA Ames Mars GCM to simulate the current-day water cycle with radiatively active clouds. Cloud fields from our baseline simulation are in generally good agreement with observations. The predicted seasonal extent and peak IR optical depths are consistent MGS/TES observations. Additionally, the thermal response to the clouds in the aphelion cloud belt (ACB) is generally consistent with observations and other climate model predictions. Notably, there is a distinct gap in the predicted clouds over the North Residual Cap (NRC) during local summer, but the clouds reappear in this simulation over the NRC earlier than the observations indicate. Polar clouds are predicted near the seasonal CO2 ice caps, but the column thicknesses of these clouds are generally too thick compared to observations. Our baseline simulation is dry compared to MGS/TES-observed water vapor abundances, particularly in the tropics and subtropics. These areas of disagreement appear to be a consistent with other current water cycle GCMs. Future avenues of investigation will target improving our understanding of what controls the vertical extent of clouds and the apparent seasonal evolution of cloud particle sizes within the ACB.

Chandra X-ray Observation of a Mature Cloud-Shock Interaction in the Bright Eastern Knot of Puppis A

NASA Technical Reports Server (NTRS)

Hwang, Una; Flanagan, Kathryn A.; Petre, Robert

2005-01-01

We present Chandra X-ray images and spectra of the most prominent cloud-shock interaction region in the Puppis A supernova remnant. The Bright Eastern Knot (BEK) has two main morphological components: (1) a bright compact knot that lies directly behind the apex of an indentation in the eastern X-ray boundary and (2) lying 1 westward behind the shock, a curved vertical structure (bar) that is separated from a smaller bright cloud (cap) by faint diffuse emission. Based on hardness images and spectra, we identify the bar and cap as a single shocked interstellar cloud. Its morphology strongly resembles the "voided sphere" structures seen at late times in Klein et al. experimental simulat.ions of cloud-shock interactions, when the crushing of the cloud by shear instabilities is well underway. We infer an intera.ction time of roughly cloud-crushing timescales, which translates to 2000-4000 years, based on the X-ray temperature, physical size, and estimated expansion of the shocked cloud. This is the first X-ray identified example of a cloud-shock interaction in this advanced phase. Closer t o the shock front, the X-ray emission of the compact knot in the eastern part of the BEK region implies a recent interaction with relatively denser gas, some of which lies in front of the remnant. The complex spatial relationship of the X-ray emission of the compact knot to optical [O III] emission suggests that there are multiple cloud interactions occurring along the line of sight.

Aerosol properties and their influences on surface cloud condensation nuclei during CAP-MBL and MC3E

NASA Astrophysics Data System (ADS)

Logan, T.; Dong, X.; Xi, B.

2016-12-01

Aerosol particles are of particular importance because of their influences on cloud development and precipitation processes over land and ocean. Aerosol physical and chemical properties and their ability to activate as cloud condensation nuclei (CCN) as well as influence CCN number concentration (NCCN) during the 2011 Midlatitude Continental Convective Clouds Experiment (MC3E) over the Southern Great Plains (SGP) region and the 2009-2010 Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) over the Azores are presented in this study. Both regions periodically observe increases in NCCN when sulfate pollution and biomass burning smoke are present but over ocean, mineral dust diminishes NCCN. During clean conditions over the ocean, sea salt is the main contributor to CCN production, and strong (weak) surface winds and turbulent conditions can enhance (diminish) NCCN. Over the SGP, there were moderate to high correlations (R > 0.5) between increased magnitudes of aerosol loading (ssp), NCCN, chemical species, and PWV suggesting a shared common transport mechanism via the Gulf of Mexico further indicating the strong dependence on air mass type (e.g., marine vs. continental). Further investigations will greatly help to understand the seasonal influences of air masses on aerosol, NCCN, and cloud properties.

Ice crystals classification using airborne measurements in mixing phase

NASA Astrophysics Data System (ADS)

Sorin Vajaiac, Nicolae; Boscornea, Andreea

2017-04-01

This paper presents a case study of ice crystals classification from airborne measurements in mixed-phase clouds. Ice crystal shadow is recorded with CIP (Cloud Imaging Probe) component of CAPS (Cloud, Aerosol, and Precipitation Spectrometer) system. The analyzed flight was performed in the south-western part of Romania (between Pietrosani, Ramnicu Valcea, Craiova and Targu Jiu), with a Beechcraft C90 GTX which was specially equipped with a CAPS system. The temperature, during the fly, reached the lowest value at -35 °C. These low temperatures allow the formation of ice crystals and influence their form. For the here presented ice crystals classification a special software, OASIS (Optical Array Shadow Imaging Software), developed by DMT (Droplet Measurement Technologies), was used. The obtained results, as expected are influenced by the atmospheric and microphysical parameters. The particles recorded where classified in four groups: edge, irregular, round and small.

Martian North Polar Water-Ice Clouds During the Viking Era

NASA Technical Reports Server (NTRS)

Tamppari, L. K.; Bass, D. S.

2000-01-01

The Viking Orbiters determined that the surface of Mars' northern residual cap consists of water ice. Observed atmospheric water vapor abundances in the equatorial regions have been related to seasonal exchange between reservoirs such as the polar caps, the regolith and between different phases in the atmosphere. Kahn modeled the physical characteristics of ice hazes seen in Viking Orbiter imaging limb data, hypothesizing that ice hazes provide a method for scavenging water vapor from the atmosphere and accumulating it into ice particles. Given that Jakosky found that these particles had sizes such that fallout times were of order one Martian sol, these water-ice hazes provided a method for returning more water to the regolith than that provided by adsorption alone. These hazes could also explain the rapid hemispheric decrease in atmospheric water in late northern summer as well as the increase during the following early spring. A similar comparison of water vapor abundance versus polar cap brightness has been done for the north polar region. They have shown that water vapor decreases steadily between L(sub s) = 100-150 deg while polar cap albedo increases during the same time frame. As a result, they suggested that late summer water-ice deposition onto the ice cap may be the cause of the cap brightening. This deposition could be due to adsorption directly onto the cap surface or to snowfall. Thus, an examination of north polar waterice clouds could lend insight into the fate of the water vapor during this time period. Additional information is contained in the original extended abstract.

Perspective view looking from the northeast to show east elevation ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Perspective view looking from the northeast to show east elevation and north (front) elevation; note portico on east side tucked under the extended gable roof of the wing-much like a shed roof - whereas the front has a projecting porch capped by a triangular pediment and cross-gable roof - Fort Hill, Clemson University Campus, Clemson, Pickens County, SC

A Study of Rapidly Developing Low Cloud Ceilings in a Stable Atmosphere at the Florida Spaceport

NASA Technical Reports Server (NTRS)

Wheeler, Mark M.; Case, Jonathan L.; Baggett, G. Wayne

2006-01-01

Forecasters at the Space Meteorology Group (SMG) issue 30 to 90 minute forecasts for low cloud ceilings at the Shuttle Landing Facility (KTTS) in Kennedy Space Center, FL for all Space Shuttle missions. Mission verification statistics have shown cloud ceilings to be the biggest forecast challenge. SMG forecasters are especially concerned with rapidly developing cloud ceilings below 8000 ft. in a stable, capped thermodynamic environment because ceilings below 8000 ft restrict Shuttle landing operations and are the most challenging to predict accurately. This project involves the development of a database of these cases over east-central Florida in order to identify the onset, location, and if possible, dissipation times of rapidly-developing low cloud ceilings. Another goal is to document the atmospheric regimes favoring this type of cloud development to improve forecast skill of such events during Space Shuttle launch and landing operations. A 10-year database of stable, rapid low cloud development days during the daylight hours was compiled for the Florida cool-season months by examining the Cape Canaveral Air Force Station sounding data, and identifying days that had high boundary layer relative humidity associated with a thermally-capped environment below 8000 ft. Archived hourly surface observations from KTTS and Melbourne, Orlando, Sanford, and Ocala, FL were then examined for the onset of cloud ceilings below 8000 ft between 1100 and 2000 UTC. Once the database was supplemented with the hourly surface cloud observations, visible satellite imagery was examined in 30-minute intervals to confirm event occurrences. This paper will present results from some of the rapidly developing cloud ceiling cases and the prevailing meteorological conditions associated with these events, focusing on potential pre-curser information that may help improve their prediction.

Dust aerosols above the south polar cap of Mars as seen by OMEGA

NASA Astrophysics Data System (ADS)

Vincendon, M.; Langevin, Y.; Poulet, F.; Bibring, J.-P.; Gondet, B.; Jouglet, D.; Omega Team

2008-08-01

The time evolution of atmospheric dust at high southern latitudes on Mars has been determined using observations of the south seasonal cap acquired in the near infrared (1-2.65 μm) by OMEGA/Mars Express in 2005. Observations at different solar zenith angles and one EPF sequence demonstrate that the reflectance in the 2.64 μm saturated absorption band of the surface CO 2 ice is mainly due to the light scattered by aerosols above most places of the seasonal cap. We have mapped the total optical depth of dust aerosols in the near-IR above the south seasonal cap of Mars from mid-spring to early summer with a time resolution ranging from one day to one week and a spatial resolution of a few kilometers. The optical depth above the south perennial cap is determined on a longer time range covering southern spring and summer. A constant set of optical properties of dust aerosols is consistent with OMEGA observations during the analyzed period. Strong variations of the optical depth are observed over small horizontal and temporal scales, corresponding in part to moving dust clouds. The late summer peak in dust opacity observed by Opportunity in 2005 propagated to the south pole contrarily to that observed in mid spring. This may be linked to evidence for dust scavenging by water ice-rich clouds circulating at high southern latitudes at this season.

A Cloudy Day on Mars

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 23 April 2002) The Science This image, centered near 49.7 N and 43.0 W (317.0 E), displays splotchy water ice clouds that obscure the surface. Most of Mars was in a relatively clear period when this image was acquired, which is why many of the other THEMIS images acquired during the same period do not have obvious signs of atmospheric dust or water ice clouds. This image is far enough north to catch the edge of the north polar hood that develops during the northern winter. This is a cap of water ice and CO₂ ice clouds that form over the Martian north pole. Mars has a number of interesting atmospheric phenomena which THEMIS will be able to view in addition to water ice clouds, including dust devils, dust storms, and tracking atmospheric temperatures with the infrared camera. The Story Anyone who's been on an airplane in a storm knows how clouds on Earth can block the view below. The thin water ice clouds on Mars might make things slightly blurry, but at least we can still see the surface. While the surface features may not be as clear in this image, it's actually kind of fascinating to see clouds at work, because we can get a sense of how the north pole on Mars influences the weather and the climate. In this image, the north pole is responsible for the presence of the clouds. Made of water ice and carbon dioxide, these clouds 'mist out' in a atmospheric 'hood' that caps the surface during the northern Martian winter, hiding it from full view of eager observers here on Earth.

An observational search for CO2 ice clouds on Mars

NASA Technical Reports Server (NTRS)

Bell, James F., III; Calvin, Wendy M.; Pollack, James B.; Crisp, David

1993-01-01

CO2 ice clouds were first directly identified on Mars by the Mariner 6 and 7 infrared spectrometer limb scans. These observations provided support for early theoretical modeling efforts of CO2 condensation. Mariner 9 IRIS temperature profiles of north polar hood clouds were interpreted as indicating that these clouds were composed of H2O ice at lower latitudes and CO2 ice at higher latitudes. The role of CO2 condensation on Mars has recently received increased attention because (1) Kasting's model results indicated that CO2 cloud condensation limits the magnitude of the proposed early Mars CO2/H2O greenhouse, and (2) Pollack el al.'s GCM results indicated that the formation of CO2 ice clouds is favorable at all polar latitudes during the fall and winter seasons. These latter authors have shown that CO2 clouds play an important role in the polar energy balance, as the amount of CO2 contained in the polar caps is constrained by a balance between latent heat release, heat advected from lower latitudes, and thermal emission to space. The polar hood clouds reduce the amount of CO2 condensation on the polar caps because they reduce the net emission to space. There have been many extensive laboratory spectroscopic studies of H2O and CO2 ices and frosts. In this study, we use results from these and other sources to search for the occurrence of diagnostic CO2 (and H2O) ice and/or frost absorption features in ground based near-infrared imaging spectroscopic data of Mars. Our primary goals are (1) to try to confirm the previous direct observations of CO2 clouds on Mars; (2) to determine the spatial extent, temporal variability, and composition (H2O/CO2 ratio) of any clouds detected; and (3) through radiative transfer modeling, to try to determine the mean particle size and optical depth of polar hood clouds, thus, assessing their role in the polar heat budget.

Comparison View of Mars Cloud Cover

NASA Technical Reports Server (NTRS)

1997-01-01

These color and black and white pictures of Mars were taken by NASA's Hubble Space Telescope just two weeks after Earth made its closest approach to the Red Planet during the 1997 opposition. When the Hubble pictures were taken Mars was at a distance of 62 million miles (100 million kilometers) and the resolution at the center of the disk is 13.5 miles/pixel (22 kilometers/pixel). Both images were made with the Wide Field and Planetary Camera 2. The color composite (left image) is constructed from three images taken in red (673 nanometers), green (502 nm) and blue (410 nm) light. The right image, in blue light only, brings out details in the cloud structure and is remarkably similar to weather satellite pictures taken of Earth. A planetary-scale wave curls around the north pole, similar in behavior to high latitude cold fronts which descend over North America and Europe during springtime.

The picture was taken when Mars was near aphelion, its farthest point from the Sun. The faint sunlight results in cold atmospheric conditions which stimulate the formation of water ice clouds. The clouds themselves further reduce atmospheric temperatures. Atmospheric heating, resulting when sunlight is absorbed by the dust, is reduced when ice forms around the dust particles and causes the dust to gravitationally settle to the ground.

These images of Mars are centered at approximately 94 degrees longitude and 23 degrees N latitude (oriented with north up). The four largest Tharsis Montes (massive extinct volcanoes) are visible as dark spots extending through the clouds. The vast canyon system, Valles Marineris, stretches across the eastern (lower right) half of the image; the Pathfinder landing site is near the eastern edge of the image. It is early summer in the northern hemisphere, and the North polar cap has retreated to about 80 degrees N latitude; the 'residual' summer cap, which is composed of water ice, is about one-third the size of the 'seasonal' winter cap, which consists mostly of carbon-dioxide frost (dry ice) condensed on the surface. The polar cap is surrounded by a 'sand sea' made up of dark sand dunes. A distinct belt of water-ice clouds extends over much of this hemisphere.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

COMPARISON VIEW OF MARS CLOUD COVER

NASA Technical Reports Server (NTRS)

2002-01-01

These color and black and white pictures of Mars were taken by NASA's Hubble Space Telescope just two weeks after Earth made its closest approach to the Red Planet during the 1997 opposition. When the Hubble pictures were taken Mars was at a distance of 62 million miles (100 million kilometers) and the resolution at the center of the disk is 13.5 miles/pixel (22 kilometers/pixel). Both images were made with the Wide Field and Planetary Camera 2. The color composite (left image) is constructed from three images taken in red (673 nanometers), green (502 nm) and blue (410 nm) light. The right image, in blue light only, brings out details in the cloud structure and is remarkably similar to weather satellite pictures taken of Earth. A planetary-scale wave curls around the north pole, similar in behavior to high latitude cold fronts which descend over North America and Europe during springtime. The picture was taken when Mars was near aphelion, its farthest point from the Sun. The faint sunlight results in cold atmospheric conditions which stimulate the formation of water ice clouds. The clouds themselves further reduce atmospheric temperatures. Atmospheric heating, resulting when sunlight is absorbed by the dust, is reduced when ice forms around the dust particles and causes the dust to gravitationally settle to the ground. These images of Mars are centered at approximately 94 degrees longitude and 23 degrees N latitude (oriented with north up). The four largest Tharsis Montes (massive extinct volcanoes) are visible as dark spots extending through the clouds. The vast canyon system, Valles Marineris, stretches across the eastern (lower right) half of the image; the Pathfinder landing site is near the eastern edge of the image. It is early summer in the northern hemisphere, and the North polar cap has retreated to about 80 degrees N latitude; the 'residual' summer cap, which is composed of water ice, is about one-third the size of the 'seasonal' winter cap, which consists mostly of carbon-dioxide frost (dry ice) condensed on the surface. The polar cap is surrounded by a 'sand sea' made up of dark sand dunes. A distinct belt of water-ice clouds extends over much of this hemisphere. Credit: Phil James (Univ. Toledo), Todd Clancy (Space Science Inst., Boulder, CO), Steve Lee (Univ. Colorado), and NASA Image files in GIF and JPEG format and captions may be accessed on the Internet via anonymous ftp from oposite.stsci.edu in /pubinfo.

The Geology of Somalia: A Selected Bibliography of Somalian Geology, Geography and Earth Science

DTIC Science & Technology

2007-02-01

31, Issue 6, Pages 302-307. Descriptors: Child, Preschool; Developing Countries; English Abstract; Humans; Nutritional Status; Primary Health Care...much smaller figures than had been reported previously. Data on the nutritional status of all children under 5 was collected at the vaccination places...gypsum beds underlying the compact sedimentary formations capping the hills. ISSN: 0365-7477. Centers for Disease Control (CDC). 1989. “ Nutritional

Spectral unmixing of hyperspectral data to map bauxite deposits

NASA Astrophysics Data System (ADS)

Shanmugam, Sanjeevi; Abhishekh, P. V.

2006-12-01

This paper presents a study about the potential of remote sensing in bauxite exploration in the Kolli hills of Tamilnadu state, southern India. ASTER image (acquired in the VNIR and SWIR regions) has been used in conjunction with SRTM - DEM in this study. A new approach of spectral unmixing of ASTER image data delineated areas rich in alumina. Various geological and geomorphological parameters that control bauxite formation were also derived from the ASTER image. All these information, when integrated, showed that there are 16 cappings (including the existing mines) that satisfy most of the conditions favouring bauxitization in the Kolli Hills. The study concludes that spectral unmixing of hyperspectral satellite data in the VNIR and SWIR regions may be combined with the terrain parameters to get accurate information about bauxite deposits, including their quality.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, J S; Lefevre, R J; Pace, J C

Ash clouds generated by erupting volcanoes represent a serious hazard to military and civil aviation. The dispersion modeling system of the Atmospheric Release Advisory Capability (ARAC) has been used to model the cloud resulting from the eruption of the Soufriere Hills volcano, Montserrat in December 1997. A clone of parts of the ARAC system, now being installed at the Air Force Weather Agency (AFWA), will enable AFWA to provide hazard guidance to military operations in the vicinity of erupting volcanoes. This paper presents ARAC's modeling results and discusses potential application of similar calculations for AFWA support during future events.

Options to Improve Rain Snow Parameterization in Surface Based Models

NASA Astrophysics Data System (ADS)

Feiccabrino, J. M.

2017-12-01

Precipitation phase determination is of upmost importance in a number of surface based hydrological, ecological, and safety models. However, precipitation phase at Earth's surface is a result of cloud and atmospheric properties not measured by surface weather stations. Nonetheless, they can be inferred from the available surface datum. This study uses 681,620 weather observations with air temperatures between -3 and 5°C and identified precipitation occurring at the time of the observation to determine simple, yet accurate, thresholds for precipitation phase determination schemes (PPDS). This dataset represents 38% and 42% of precipitation observations over a 16 year period for 85 Swedish, and 84 Norwegian weather stations. The misclassified precipitation (error) from PPDS using AT, dew-point temperature (DT) and wet-bulb temperature (WB) thresholds were compared using a single threshold PPDS. The Norwegian observations between -3 and 5°C resulted in 11.64%, 11.21%, and 8.42% error for DT (-0.2°C), AT (1.2°C), and WB (0.3°C) thresholds respectively. Individual station thresholds had a range of -0.7 to 1.2°C, -1.2 to 0.9°C, and -0.1 to 2.5°C for WB, DP, and AT respectively. To address threshold variance while decreasing error, weather stations were grouped into nine landscape categories; windward (WW) ocean, WW coast, WW fjord, WW hill, WW mountain, leeward (LW) mountain, LW hill, LW rolling hills, and LW coast. Landscape classification was based on location relative to the Scandinavian Mountains, and the % water or range of elevation within 15KM. Within landscapes, stations share similar land atmosphere exchanges which differ from other landscapes. These differences change optimal thresholds for PPDS between landscapes. Also tested were threshold temperature affects based on assumed atmospheric differences for the following observation groups; 1.) occurring before and after an air mass boundary, 2.) with different water temperatures and/or NAO phases, 3.) with snow cover, 4.) coupled with higher elevation stations and 5.) with different cloud heights. For example, in Norway, as the unsaturated layer depth beneath clouds increased, AT thresholds warmed. Cloud height adjusted AT thresholds reduced error by 5% before threshold adjustments for landscapes.

Water Cycling in the North Polar Region of Mars

NASA Technical Reports Server (NTRS)

Tamppari, L. K.; Smith, M. D.; Bass, D. S.

2003-01-01

To date, there has been no comprehensive study to understand the partitioning of water into vapor and ice clouds, and the associated effects of dust and surface temperature in the north polar region. Ascertaining the degree to which water is transported out of the cap region versus within the cap region will give much needed insight into the overall story of water cycling on a seasonal basis. In particular, understanding the mechanism for the polar cap surface albedo changes would go along way in comprehending the sources and sinks of water in the northern polar region. We approach this problem by examining Thermal Emission Spectrometer (TES) atmospheric and surface data acquired in the northern summer season and comparing it to Viking data when possible. Because the TES instrument spans the absorption bands of water vapor, water ice, dust, and measures surface temperature, all three aerosols and surface temperature can be retrieved simultaneously. This presentation will show our latest results on the water vapor, water-ice clouds seasonal and spatial distributions, as well as surface temperatures and dust distribution which may lend insight into where the water is going.

Constitutive models for the Etchegoin Sands, Belridge Diatomite, and overburden formations at the Lost Hills oil field, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

FOSSUM,ARLO F.; FREDRICH,JOANNE T.

2000-04-01

This report documents the development of constitutive material models for the overburden formations, reservoir formations, and underlying strata at the Lost Hills oil field located about 45 miles northwest of Bakersfield in Kern County, California. Triaxial rock mechanics tests were performed on specimens prepared from cores recovered from the Lost Hills field, and included measurements of axial and radial stresses and strains under different load paths. The tested intervals comprise diatomaceous sands of the Etchegoin Formation and several diatomite types of the Belridge Diatomite Member of the Monterey Formation, including cycles both above and below the diagenetic phase boundary betweenmore » opal-A and opal-CT. The laboratory data are used to drive constitutive parameters for the Extended Sandler-Rubin (ESR) cap model that is implemented in Sandia's structural mechanics finite element code JAS3D. Available data in the literature are also used to derive ESR shear failure parameters for overburden formations. The material models are being used in large-scale three-dimensional geomechanical simulations of the reservoir behavior during primary and secondary recovery.« less

Microphysical characterization of winter cloud systems during a research flight campaign

NASA Astrophysics Data System (ADS)

Fernández-González, Sergio; Sánchez, José Luis; Valero, Francisco; Gascón, Estíbaliz; Merino, Andrés; Hermida, Lucía; López, Laura; Marcos, José Luis; García-Ortega, Eduardo

2015-04-01

The lack of accuracy in the knowledge of cloud microphysics leads to aviation risks, which have caused numerous crashes, mainly owing to aircraft icing (e.g., an EMB-120 crashed in Detroit, Michigan in 1997, and an ATR-72 crashed near Roselawn, Indiana in 1994). Further, this lack is a source of uncertainty in numerical weather forecasting models, since commonly used parameterizations often overestimate ice water content and underestimate supercooled liquid water. This makes the collection of data on cloud microphysical characteristics very useful toward improving the forecasting of icing conditions. Ten research flights were conducted during the winters of 2011/12 and 2012/13. Their goal was to determine dominant microphysical conditions of winter cloud systems traversing the Guadarrama Mountains in the central Iberian Peninsula. The aircraft was a C-212-200, equipped with a Cloud, Aerosol, and Precipitation Spectrometer (CAPS) under the left wing. Data of temperature and Liquid Water Content (LWC), registered by the CAPS probe, were used in the study. Furthermore, we thoroughly analyzed images taken by a Cloud Imaging Probe Grayscale (CIP-GS), capable of measuring hydrometeors between 25 and 1,550 µm in size, and representing them in a 2D image. The various types of hydrometeors observed during these flights are described, along with microphysical processes inferred from the CIP-GS images. ACKNOWLEDGEMENTS S. Fernández-González acknowledges grant support from the FPU program (AP 2010-2093). This study was also supported by grants from GRANIMETRO (CGL2010-15930) and MICROMETEO (IPT-310000-2010-22). The authors thank INTA for the research flights.

The role of calcium in the desensitization of capsaicin responses in rat dorsal root ganglion neurons.

PubMed

Koplas, P A; Rosenberg, R L; Oxford, G S

1997-05-15

Capsaicin (Cap) is a pungent extract of the Capsicum pepper family, which activates nociceptive primary sensory neurons. Inward current and membrane potential responses of cultured neonatal rat dorsal root ganglion neurons to capsaicin were examined using whole-cell and perforated patch recording methods. The responses exhibited strong desensitization operationally classified as acute (diminished response during constant Cap exposure) and tachyphylaxis (diminished response to successive applications of Cap). Both acute desensitization and tachyphylaxis were greatly diminished by reductions in external Ca2+ concentration. Furthermore, chelation of intracellular Ca2+ by addition of either EGTA or bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid to the patch pipette attenuated both forms of desensitization even in normal Ca2+. Release of intracellular Ca2+ by caffeine triggered acute desensitization in the absence of extracellular Ca2+, and barium was found to effectively substitute for calcium in supporting desensitization. Cap activated inward current at an ED50 of 728 nM, exhibiting cooperativity (Hill coefficient, 2.2); however, both forms of desensitization were only weakly dependent on [Cap], suggesting a dissociation between activation of Cap-sensitive channels and desensitization. Removal of ATP and GTP from the intracellular solutions resulted in nearly complete tachyphylaxis even with intracellular Ca2+ buffered to low levels, whereas changes in nucleotide levels did not significantly alter the acute form of desensitization. These data suggest a key role for intracellular Ca2+ in desensitization of Cap responses, perhaps through Ca2+-dependent dephosphorylation at a locus that normally sustains Cap responsiveness via ATP-dependent phosphorylation. It also seems that the signaling mechanisms underlying the two forms of desensitization are not identical in detail.

Carbon Dioxide Snow Storms During the Polar Night on Mars

NASA Technical Reports Server (NTRS)

Toon, Owen B.; Colaprete, Anthony

2001-01-01

The Mars Orbiter Laser Altimeter (MOLA) detected clouds associated with topographic features during the polar night on Mars. While uplift generated from flow over mountains initiates clouds on both Earth and Mars, we suggest that the Martian clouds differ greatly from terrestrial mountain wave clouds. Terrestrial wave clouds are generally compact features with sharp edges due to the relatively small particles in them. However, we find that the large mass of condensible carbon dioxide on Mars leads to clouds with snow tails that may extend many kilometers down wind from the mountain and even reach the surface. Both the observations and the simulations suggest substantial carbon dioxide snow precipitation in association with the underlying topography. This precipitation deposits CO2, dust and water ice to the polar caps, and may lead to propagating geologic features in the Martian polar regions.

Polar Cap Disturbances: Mesosphere and Thermosphere-Ionosphere Response to Solar-Terrestrial Interactions

NASA Technical Reports Server (NTRS)

Sivjee, G.; McEwen, D.; Walterscheid, R.

2003-01-01

The Polar Cap is the Upper-Atmosphere cum Mag-netosphere region which is enclosed by the poleward boundary of the Auroral Oval and is threaded by open geomagnetic tield lines. In this region, there is normally a steady precipition (Polar "drizzle") of low energy (w 300eV) electrons that excite optical emissions from the ionosphere. At times, enhanced ionization patches are formed near the Dayside Cusp regions that drift across the Polar Cap towards the Night Sector of the Auroral Oval. Discrete auroral arcs and auroras formed during Solar Magnetic Cloud (SMC)/Coronal Mass Ejection (CME) events are also observed in the Polar Cap. Spectrophotometric observations of all these Polar Cap phenomena provide a measure of the average energy as well a energy flux of the electrons precipitating in the Polar Cap region during these disturbances. Such measurements also point to modulations of the Polar Cap Mesosphere-Lower Thermosphere (MLT) air density and temperature by zonally symmetric tides whose Hough functions peak in the Polar region. MLT cooling during Stratospheric Warming events and their relation to Polar Vortex and associated Gravity wave activities are also observed at the Polar Cap sites.

A Cultural Resources Inventory of the Pearl River Basin, Louisiana and Mississippi. Volume I.

DTIC Science & Technology

1982-04-01

The Jackson Prairie is characterized by gently rolling terrain with deposits of terrace sands capping some of the higher hills (Baughman 1971). The...11 I I I higher level deposits usually are more graveliferous and !he lower depo- sits are predominantly sand. The Pleistocene gravels could have pro... Women Voters of Slidell 1965). Theses and dissertations often provide valuable information for researchers. Some of the subjects which relate to the

Characterization of clouds in Titan's tropical atmosphere

USGS Publications Warehouse

Griffith, C.A.; Penteado, P.; Rodriguez, S.; Le, Mouelic S.; Baines, K.H.; Buratti, B.; Clark, R.; Nicholson, P.; Jaumann, R.; Sotin, Christophe

2009-01-01

Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere. Radiative transfer analyses indicate similarities between summer polar and tropical methane clouds. Like their southern counterparts, tropical clouds consist of particles exceeding 5 ??m. They display discrete structures suggestive of convective cumuli. They prevail at a specific latitude band between 8??-20?? S, indicative of a circulation origin and the beginning of a circulation turnover. Yet, unlike the high latitude clouds that often reach 45 km altitude, these discrete tropical clouds, so far, remain capped to altitudes below 26 km. Such low convective clouds are consistent with the highly stable atmospheric conditions measured at the Huygens landing site. Their characteristics suggest that Titan's tropical atmosphere has a dry climate unlike the south polar atmosphere, and despite the numerous washes that carve the tropical landscape. ?? 2009. The American Astronomical Society.

Hubble the Rotation of Uranus

NASA Image and Video Library

1998-08-02

These three NASA Hubble Space Telescope images of the planet Uranus reveal the motion of a pair of bright clouds in the planet southern hemisphere, and a high altitude haze that forms a cap above the planet south pole.

Excitation of nonlinear wave patterns in flowing complex plasmas

NASA Astrophysics Data System (ADS)

Jaiswal, S.; Bandyopadhyay, P.; Sen, A.

2018-01-01

We describe experimental observations of nonlinear wave structures excited by a supersonic mass flow of dust particles over an electrostatic potential hill in a dusty plasma medium. The experiments have been carried out in a Π- shaped experimental (DPEx) device in which micron sized Kaolin particles are embedded in a DC glow discharge Argon plasma. An equilibrium dust cloud is formed by maintaining the pumping speed and gas flow rate and the dust flow is induced either by suddenly reducing the height of a potential hill or by suddenly reducing the gas flow rate. For a supersonic flow of the dust fluid precursor solitons are seen to propagate in the upstream direction while wake structures propagate in the downstream direction. For flow speeds with a Mach number greater than 2 the dust particles flowing over the potential hill give rise to dispersive dust acoustic shock waves. The experimental results compare favorably with model theories based on forced K-dV and K-dV Burger's equations.

Glacial Inception in north-east Canada: The Role of Topography and Clouds

NASA Astrophysics Data System (ADS)

Birch, Leah; Tziperman, Eli; Cronin, Timothy

2016-04-01

Over the past 0.8 million years, ice ages have dominated Earth's climate on a 100 thousand year cycle. Interglacials were brief, sometimes lasting only a few thousand years, leading to the next inception. Currently, state-of-the-art global climate models (GCMs) are incapable of simulating the transition of Earth's climate from interglacial to glaciated. We hypothesize that this failure may be related to their coarse spatial resolution, which does not allow resolving the topography of inception areas, and their parameterized representation of clouds and atmospheric convection. To better understand the small scale topographic and cloud processes mis-represented by GCMs, we run the Weather Research and Forecasting model (WRF), which is a regional, cloud-resolving atmospheric model capable of a realistic simulation of the regional mountain climate and therefore of surface ice and snow mass balance. We focus our study on the mountain glaciers of Canada's Baffin Island, where geologic evidence indicates the last inception occurred at 115kya. We examine the sensitivity of mountain glaciers to Milankovitch Forcing, topography, and meteorology, while observing impacts of a cloud resolving model. We first verify WRF's ability to simulate present day climate in the region surrounding the Penny Ice Cap, and then investigate how a GCM-like biased representation of topography affects sensitivity of this mountain glacier to Milankovitch forcing. Our results show the possibility of ice cap growth on an initially snow-free landscape with realistic topography and insolation values from the last glacial inception. Whereas, smoothed topography as seen in GCMs has a negative surface mass balance, even with the relevant orbital parameter configuration. We also explore the surface mass balance feedbacks from an initially ice-covered Baffin Island and discuss the role of clouds and convection.

Characterizing synoptic and cloud variability in the northern atlantic using self-organizing maps

NASA Astrophysics Data System (ADS)

Fish, Carly

Low-level clouds have a significant influence on the Earth's radiation budget and it is thus imperative to understand their behavior within the marine boundary layer (MBL). The cloud properties in the Northeast Atlantic region are highly variable in space and time and are a research focus for many atmospheric scientists. Characterizing the synoptic patterns in the region through the implementation of self-organizing maps (SOMs) enables a climatological grasp of cloud and atmospheric fields. ERA -- Interim and MODIS provide the platform to explore the variability in the Northeast Atlantic for over 30 years of data. Station data comes from CAP -- MBL on Graciosa Island in the Azores, which lies in a strong gradient of cloud and other atmospheric fields, offer an opportunity to incorporate an observational aspect for the years of 2009 and 2010.

Intensity, frequency and spatial configuration of winter temperature inversions in the closed La Brevine valley, Switzerland

NASA Astrophysics Data System (ADS)

Vitasse, Yann; Klein, Geoffrey; Kirchner, James W.; Rebetez, Martine

2017-11-01

Some of the world's valleys are famous for having particularly cold microclimates. The La Brevine valley, in the Swiss Jura Mountains, holds the record for the lowest temperature ever measured in an inhabited location in Switzerland. We studied cold air pools (CAPs) in this valley during the winter of 2014-2015 using 44 temperature data loggers distributed between 1033 and 1293 m asl. Our goals were to (i) describe the climatic conditions under which CAPs form in the valley, (ii) examine the spatial configuration and the temperature structure of the CAPs and (iii) quantify how often temperature inversions occur in winter using long-term series of temperature from the valley floor. Our results show that CAPs occurred every second night, on average, during the winter of 2014-2015 and were typically formed under cloudless, windless and high-pressure conditions. Strong temperature inversions up to 28 °C were detected between the valley floor and the surrounding hills. The spatial temperature structure of the CAPs varies among the different inversion days, with the upper boundary of the cold pool generally situated at about 1150 m asl. Although mean temperatures have increased in this area over the period 1960-2015 in connection with climate change, the occurrences of extreme cold temperatures did not decrease in winter and are highly correlated with the North Atlantic Oscillation and the East Atlantic indices. This suggests that CAPs in sheltered valleys are largely decoupled from the free atmosphere temperature and will likely continue to occur in the next decades under warmer conditions.

Snow Clouds and the Carbon Dioxide Cycle on Mars

NASA Astrophysics Data System (ADS)

Hayne, P. O.; Paige, D. A.

2009-12-01

The present climate of Mars is strongly influenced by the energy balance at the planet’s poles, with ~30% of the atmospheric mass exchanged seasonally with the polar ice caps. While the spring and summer sublimation process is observable in sunlight, the deposition process occurs in the darkness of polar night. We present direct radiometric observations of carbon dioxide snow clouds from the Mars Climate Sounder (MCS) and estimate the rate of deposition due to snowfall. We also present radiative transfer models capable of reproducing the observations and providing constraints on the radiative and thermal properties of the cap-atmosphere system. Snow clouds display a multi-layered structure with greatest opacity near the surface and extending to typical altitudes of about 20 km, with equivalent normal visible optical depths of ~0.1. Our modeling suggests the observed carbon dioxide snow grains are ~10 μm in radius, implying modest deposition rates, and suggesting the majority of the seasonal cap is deposited in a vertical region within one MCS field of view (or ~1 km) of the surface. Models reproducing the MCS limb observations only reproduce the nadir observations if the surface (or near-surface) is an optically thick layer of small (< 100 μm radius) carbon dioxide grains, which are therefore the primary cause of radiometrically cold areas (“cold spots”) observed since the Viking era. For the extreme polar regions, a persistent, ~500 km diameter snow cloud is strongly coupled to the most active cold spots, and smaller clouds (< 50 km diameter) in the latitude range 60-80°, though unobserved, cannot be ruled out by the MCS data. Based on this correlation, and observations of cold spots recurring near topographic slopes, we conclude that deposition is indeed linked to cloud formation, with the majority of material condensing below ~1 km altitude. Optically thin water ice layers are necessary to accurately model the MCS spectrum, particularly at altitudes above 20 km. This suggests water ice functions as the required condensation nucleus, consistent with earlier laboratory and theoretical studies. Important hemispherical differences are observed in the deposition process: 1) northern clouds are optically thicker at middle altitudes, ~5-15 km; 2) southern clouds are more often “detached”, showing a local maximum opacity near 20-25 km altitude; 3) mode particle radii are larger (~100 μm versus ~10 μm) in the north. Total normal optical depths are typically higher by a factor of ~2 in the north, and water ice content is relatively higher. Energy balance constraints can be placed on the system by MCS observations of outgoing infrared flux, which we map through time as an effective emissivity by taking account of the topography from MOLA and the expected frost point temperature.

Time-variability of Polar Winter Snow Clouds on Mars

NASA Astrophysics Data System (ADS)

Hayne, P. O.; Kass, D. M.; Kleinboehl, A.; Schofield, J. T.; McCleese, D. J.

2015-12-01

Carbon dioxide snow clouds are known to occur in the polar regions on Mars during the long polar night. Earlier studies have shown that a substantial fraction (up to ~20%) of the seasonal ice caps of Mars can be deposited as CO2 snowfall. The presence of optically thick clouds can also strongly influence the polar energy balance, by scattering thermal radiation emitted by the surface and lower atmosphere. Furthermore, snow deposition is likely to affect the surface morphology and subsequent evolution of the seasonal caps. Therefore, both the spatial distribution and time variability of polar snow clouds are important for understanding their influence on the Martian CO2cycle and climate. However, previous investigations have suffered from relatively coarse time resolution (typically days), coarse or incomplete spatial coverage, or both. Here we report results of a dedicated campaign by the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter, to observe polar CO2 clouds with an unprecedented time-resolution within the same spatial region. By scanning the MCS field of view, we acquired observations directly over the north pole for every ~2hr orbit over the course of several days. This was repeated during two separate periods in northern winter. The 2 hr sampling frequency enables the detailed study of cloud evolution. These observations were also compared to a cloud-free, control region just off the pole, which was sampled in the same way. Results from this experiment show that the north polar CO2 clouds are dynamic, and appear to follow a consistent pattern: Beginning with a relatively clear atmosphere, the cloud rapidly grows to ~25 - 30 km altitude in < 2 hr. Then, the altitude of the cloud tops diminishes slowly, reaching near the surface after ~6 - 10 hr. We interpret this slow decay as the precipitation of snow particles, which constrains their size to be ~10 - 100 μm. Also pervasive in this season are water ice clouds, which may provide condensation nuclei for the CO2. The interplay between these two atmospheric aerosol species on short timescales is a potentially fruitful area of future research, enabled by these unique observations. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Sahara Desert, Algeria

NASA Image and Video Library

1994-09-30

STS068-228-081 (30 September-11 October 1994) --- This northwest-looking view shows central Algeria with an unusual amount of cloud cover, responsible for one of the infrequent bouts of rain in the Sahara Desert. The lope-shaped, red sand dunes mass in the center of the view is one of the most prominent features in the Sahara as seen from the Space Shuttle Endeavour. It is known as the Tifernine Dunes. The Atlas Mountains (top) are only apparent in this view because of the clouds, which cap their summits.

The variability of California summertime marine stratus: impacts on surface air temperatures

USGS Publications Warehouse

Iacobellis, Sam F.; Cayan, Daniel R.

2013-01-01

This study investigates the variability of clouds, primarily marine stratus clouds, and how they are associated with surface temperature anomalies over California, especially along the coastal margin. We focus on the summer months of June to September when marine stratus are the dominant cloud type. Data used include satellite cloud reflectivity (cloud albedo) measurements, hourly surface observations of cloud cover and air temperature at coastal airports, and observed values of daily surface temperature at stations throughout California and Nevada. Much of the anomalous variability of summer clouds is organized over regional patterns that affect considerable portions of the coast, often extend hundreds of kilometers to the west and southwest over the North Pacific, and are bounded to the east by coastal mountains. The occurrence of marine stratus is positively correlated with both the strength and height of the thermal inversion that caps the marine boundary layer, with inversion base height being a key factor in determining their inland penetration. Cloud cover is strongly associated with surface temperature variations. In general, increased presence of cloud (higher cloud albedo) produces cooler daytime temperatures and warmer nighttime temperatures. Summer daytime temperature fluctuations associated with cloud cover variations typically exceed 1°C. The inversion-cloud albedo-temperature associations that occur at daily timescales are also found at seasonal timescales.

Water adsorption constrained Frenkel-Halsey-Hill adsorption activation theory: Montmorillonite and illite

NASA Astrophysics Data System (ADS)

Hatch, Courtney D.; Greenaway, Ann L.; Christie, Matthew J.; Baltrusaitis, Jonas

2014-04-01

Fresh mineral aerosol has recently been found to be effective cloud condensation nuclei (CCN) and contribute to the number of cloud droplets in the atmosphere due to the effect of water adsorption on CCN activation. The work described here uses experimental water adsorption measurements on Na-montmorillonite and illite clay to determine empirical adsorption parameters that can be used in a recently derived theoretical framework (Frenkel-Halsey-Hill Activation Theory, FHH-AT) that accounts for the effect of water adsorption on CCN activation. Upon fitting the Frenkel-Halsey-Hill (FHH) adsorption model to water adsorption measurements, we find FHH adsorption parameters, AFHH and BFHH, to be 98 ± 22 and 1.79 ± 0.11 for montmorillonite and 75 ± 17 and 1.77 ± 0.11 for illite, respectively. The AFHH and BFHH values obtained from water adsorption measurements differ from values reported previously determined by applying FHH-AT to CCN activation measurements. Differences in FHH adsorption parameters were attributed to different methods used to obtain them and the hydratable nature of the clays. FHH adsorption parameters determined from water adsorption measurements were then used to calculate the critical super-saturation (sc) for CCN activation using FHH-AT. The relationship between sc and the dry particle diameter (Ddry) gave CCN activation curve exponents (xFHH) of -0.61 and -0.64 for montmorillonite and illite, respectively. The xFHH values were slightly lower than reported previously for mineral aerosol. The lower exponent suggests that the CCN activity of hydratable clays is less sensitive to changes in Ddry and the hygroscopicity parameter exhibits a broader variability with Ddry compared to more soluble aerosols. Despite the differences in AFHH, BFHH and xFHH, the FHH-AT derived CCN activities of montmorillonite and illite are quite similar to each other and in excellent agreement with experimental CCN measurements resulting from wet-generated clay aerosol. This study illustrates that FHH-AT using adsorption parameters constrained by water adsorption is a simple, valid method for predicting CCN activation of fresh clay minerals and provides parameters that can be used in atmospheric models to study the effect of mineral dust aerosol on cloud formation and climate.

Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

NASA Astrophysics Data System (ADS)

van Pinxteren, Dominik; Wadinga Fomba, Khanneh; Mertes, Stephan; Müller, Konrad; Spindler, Gerald; Schneider, Johannes; Lee, Taehyoung; Collett, Jeffrey L.; Herrmann, Hartmut

2016-03-01

Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a three-stage and a five-stage collector were applied and samples were analysed for inorganic ions (SO42-,NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 µmol L-1 for ammonium, nitrate, and sulfate respectively, between 4 and 27 µmol L-1 for minor ions, 5.4 µmol L-1 for H2O2 (aq), 1.9 µmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC × 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). The similar variability of solute concentrations and CWLs together with the results of back-trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC), were the main factor controlling bulk solute concentrations for the cloud studied. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CVI) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic differences and limitations of the approaches (such as outgassing of dissolved gases during residual particle sampling). Scavenging efficiencies (SEs) of aerosol constituents were 0.56-0.94, 0.79-0.99, 0.71-98, and 0.67-0.92 for SO42-, NO3-, NH4+, and DOC respectively when calculated as event means with in-cloud data only. SEs estimated using data from an upwind site were substantially different in many cases, revealing the impact of gas-phase uptake (for volatile constituents) and mass losses across Mt. Schmücke likely due to physical processes such as droplet scavenging by trees and/or entrainment. Drop size-resolved cloud water concentrations of major ions SO42-, NO3-, and NH4+ revealed two main profiles: decreasing concentrations with increasing droplet size and "U" shapes. In contrast, profiles of typical coarse particle mode minor ions were often increasing with increasing drop size, highlighting the importance of a species' particle concentration size distribution for the development of size-resolved solute concentration patterns. Concentration differences between droplet size classes were typically < 2 for major ions from the three-stage collector and somewhat more pronounced from the five-stage collector, while they were much larger for minor ions. Due to a better separation of droplet populations, the five-stage collector was capable of resolving some features of solute size dependencies not seen in the three-stage data, especially sharp concentration increases (up to a factor of 5-10) in the smallest droplets for many solutes.

Elevation Change of Drangajokull, Iceland, from Cloud-Cleared ICESat Repeat Profiles and GPS Ground-Survey Data

NASA Technical Reports Server (NTRS)

Shuman, Christopher A.; Sigurdsson, Oddur; Williams, Richard, Jr.; Hall, Dorothy K.

2009-01-01

Located on the Vestfirdir Northwest Fjords), DrangaJokull is the northernmost ice map in Iceland. Currently, the ice cap exceeds 900 m in elevation and covered an area of approx.l46 sq km in August 2004. It was about 204 sq km in area during 1913-1914 and so has lost mass during the 20th century. Drangajokull's size and accessibility for GPS surveys as well as the availability of repeat satellite altimetry profiles since late 2003 make it a good subject for change-detection analysis. The ice cap was surveyed by four GPS-equipped snowmobiles on 19-20 April 2005 and has been profiled in two places by Ice, Cloud. and land Elevation Satellite (ICESat) 'repeat tracks,' fifteen times from late to early 2009. In addition, traditional mass-balance measurements have been taken seasonally at a number of locations across the ice cap and they show positive net mass balances in 2004/2005 through 2006/2007. Mean elevation differences between the temporally-closest ICESat profiles and the GPS-derived digital-elevation model (DEM)(ICESat - DEM) are about 1.1 m but have standard deviations of 3 to 4 m. Differencing all ICESat repeats from the DEM shows that the overall elevation difference trend since 2003 is negative with losses of as much as 1.5 m/a from same season to same season (and similar elevation) data subsets. However, the mass balance assessments by traditional stake re-measurement methods suggest that the elevation changes where ICESat tracks 0046 and 0307 cross Drangajokull are not representative of the whole ice cap. Specifically, the area has experienced positive mass balance years during the time frame when ICESat data indicates substantial losses. This analysis suggests that ICESat-derived elevations may be used for multi-year change detection relative to other data but suggests that large uncertainties remain. These uncertainties may be due to geolocation uncertainty on steep slopes and continuing cloud cover that limits temporal and spatial coverage across the area.

Nature and Stability of the Martian Seasonal Water Cycle

NASA Astrophysics Data System (ADS)

Richardson, M. I.; Wilson, R. J.

2001-12-01

Which components control the contemporary water cycle and what is the nature of the control mechanisms? These questions are at the heart of understanding how the Martian exchangeable water budget adjusts to perturbations and changes in the climate system. Analysis of a water cycle model embedded in the GFDL Mars GCM provides a paradigm for the water cycle as a feedback system, providing information on the important control points and response times. Much information on this system derives from monitoring the evolution towards steady state--one that resembles the observed water vapour and ice cloud distributions. The most important exchange balance in the system is that between the northern polar atmosphere and the rest of the planet. As the major net source for water, the northern residual water ice cap is active during summer, in the window of time between the sublimation and recondensation of the seasonal CO2 cap. At this time, water is exported from the northern polar atmosphere at a rate determined by the mixing capacity of the atmosphere and the amount of water held in the polar atmosphere. The latter is determined by the cap surface temperature. During the remainder of the year, water is returned to the pole. This return flux is determined by the atmospheric mixing capacity and the amount of water vapour held in the tropical and winter extratropical atmosphere. Steady-state is achieved when these fluxes balance. For a given climate state (and a roughly repeatable annual cycle of mixing), the outflux and influx of polar water are controlled by separate variables. Holding the cap temperature constant, the outflux will remain constant. Any perturbation to the global water budget will result in a change in the return flux that tends to oppose the sense of the perturbation--the perturbation will be damped. In the same way, a change in cap temperature (e.g. associated with a change in albedo) will result in changed water outflow. Again, this will tend to change the non-polar water vapour budget and hence the polar water influx so as to develop a new steady-state. It is important to note that only in this case is the steady-state global humidity changed: a given cap temperature and seasonal cycle of mixing capacity specifies a bulk steady-state atmospheric humidity. In all cases, the regolith acts as a damper on the system and adjusts to the global water distribution dictated ultimately by the northern cap. The model also suggests fast adjustment times, on order decades. A number of factors can affect atmospheric mixing capacity. As climate forcing factors change (associated with obliquity or greenhouse gas loading) the mixing capacity will change--an area for future study. The current mixing capacity of the atmosphere is also different from one that would obtain without atmospheric water condensation and sedimentation. Model clouds play important roles in returning water to the residual ice cap in northern summer, and significantly altering interhemispheric transport from that which would occur without clouds. As with previous studies, the southern polar cap acts as a permanent sink for water. The model and resulting paradigm for the water cycle can be used in very preliminary studies of past climate states. Forcing the model with an obliquity of 45 deg., the seasonal water ice caps become significantly more extended, reaching into the summer hemisphere. In fact, the seasonal caps "overlap" in the northern tropics, generating a year-round surface ice belt. Much work remains to be done in understanding water ice transport and exchange processes before models of paleoclimate can be of widespread utility--of which analysis of data from MGS and future missions will be key.

POST - A New Look at Stratocumulus

DTIC Science & Technology

2010-07-01

1 10.1 POST - A New Look at Stratocumulus H. Gerber , G. Frick , S. P. Malinowski , W . Kumula , S...interesting to note that another flight shows entirely different behavior: Malinowski et al (2010) finds positive T’ in LW C holes near cloud top in...parameterization will also rely on ongoing analysis by POST colleagues described in Malinowski et al (2010), Hill et al (2010), W ang, Q., et al (2010), and W ang

ENGINEERING-GEOLOGY SITE APPRAISAL OF THE FEDERAL CAPITAL TERRITORY, NIGERIA.

USGS Publications Warehouse

Ege, J.R.; Griffitts, W.R.; Overstreet, W.C.

1985-01-01

The 7,700-km**2-area Federal Capital Territory, Nigeria, is underlain by crystalline igneous and metamorphic rocks of Precambrian age. Laterite caps many hills of Cretaceous rock, some hills of Precambrian rock, and crops out near stream banks in the east and northeast. The most conspicuous structural features are a broad 'J'-shaped fold traversing the eastern and central part of the Territory and a north-trending shear zone along the eastern boundary. The soils of the Territory are lateritic and belong to the SW-SP-SM (Unified Soil Classification System) groups covering Precambrian migmatites, gneisses and granites and the SC group covering Cretaceous sediments and Precambrian mica-rich schists. The engineering characteristics of the rocks are medium- to high-strength massive and gneissic rock, low-to medium-strength bedded rock, and low-strength foliated and sheared rock. An area of at least 800 km**2 is free from apparent geological hazards and should be suitable for construction of a capital city, its environs and supporting facilities.

Satellite observations of polar mesospheric clouds by the solar backscattered ultraviolet spectral radiometer - Evidence of a solar cycle dependence

NASA Technical Reports Server (NTRS)

Thomas, Gary E.; Mcpeters, Richard D.; Jensen, Eric J.

1991-01-01

Results are presented on eight years of satellite observations of the polar mesospheric clouds (PMCs) by the SBUV spectral radiometer, showing that PMCs occur in the summertime polar cap regions of both hemispheres and that they exhibit year-to-year variability. It was also found that the increase in the PMC occurrence frequency was inversely correlated with solar activity. Two kinds of hemispherical asymmetries could be identified: (1) PMCs in the Northern Hemisphere were significantly brighter than in the Southern Hemisphere, in accordance with previous results derived from SME data; and (2) the solar cycle response in the south is more pronounced than in the north. The paper also describes the cloud detection algorithm.

Development and lithogenesis of the palustrine and calcrete deposits of the Dibdibba Alluvial Fan, Kuwait

NASA Astrophysics Data System (ADS)

AlShuaibi, Arafat A.; Khalaf, Fikry I.

2011-08-01

A model is proposed for the development of the Quaternary palustrine carbonate-calcrete association, which occurs as hard crust capping low hills at a distal flood plain of Al Dibdibba alluvial fan located at southwestern Kuwait. Field occurrence, detailed petrographic investigation and geochemical analysis revealed that a single cycle of groundwater calcrete with vertical gradational maturity pattern was developed. This represents a continuous sedimentological cycle during which flood sheet conditions prevailed with intermittent periods of humid and arid conditions. Subsequently, calcitic micrite was continuously precipitated from small, shallow, local, isolated and short lived ponds fringed by freshwater marshes with abundant charophyte meadows. The latter were developed as a result of flooding scattered depressions by groundwater supersaturated with respect to calcite due to rise of groundwater table. The deposition of two facies of carbonate muds, namely; biomicrite and pelintraclasts skeletal micrites was followed by a drought phase which witnessed desiccation of the fresh water ponds and significant drop in groundwater level. A sequence of pedogenic and diagenetic processes acted on the deposited carbonate muds are manifested by: (a) desiccation cracks, (b) micrite neomorphism, (c) infilling of root burrows and some cracks by aeolian siliciclastics, (d) karstification, (e) marmorization, (f) calcretization of root burrow infill and development of pseudo-rhizocrete, (g) calcite cementation and mineral authigenesis, and (h) silcretization. These processes are responsible for the development of hard palustrine carbonate crust. At the advent of aridity, the whole system of Al Dibdibba alluvial fan was subjected to deflation. This resulted in reversing the paleotopography of the hard crusted palustrine depressions into carbonate capped domal hills.

Cloud water composition during HCCT-2010: Scavenging efficiencies, solute concentrations, and droplet size dependence of inorganic ions and dissolved organic carbon

NASA Astrophysics Data System (ADS)

van Pinxteren, D.; Fomba, K. W.; Mertes, S.; Müller, K.; Spindler, G.; Schneider, J.; Lee, T.; Collett, J.; Herrmann, H.

2015-09-01

Cloud water samples were taken in September/October 2010 at Mt. Schmücke in a rural, forested area in Germany during the Lagrange-type Hill Cap Cloud Thuringia 2010 (HCCT-2010) cloud experiment. Besides bulk collectors, a 3-stage and a 5-stage collector were applied and samples were analysed for inorganic ions (SO42-, NO3-, NH4+, Cl-, Na+, Mg2+, Ca2+, K+), H2O2 (aq), S(IV), and dissolved organic carbon (DOC). Campaign volume-weighted mean concentrations were 191, 142, and 39 μmol L-1 for ammonium, nitrate, and sulfate, respectively, between 4 and 27 μmol L-1 for minor ions, 5.4 μmol L-1 for H2O2 (aq), 1.9 μmol L-1 for S(IV), and 3.9 mgC L-1 for DOC. The concentrations compare well to more recent European cloud water data from similar sites. On a mass basis, organic material (as DOC · 1.8) contributed 20-40 % (event means) to total solute concentrations and was found to have non-negligible impact on cloud water acidity. Relative standard deviations of major ions were 60-66 % for solute concentrations and 52-80 % for cloud water loadings (CWLs). Contrary to some earlier suggestions, the similar variability of solute concentrations and CWLs together with the results of back trajectory analysis and principal component analysis, suggests that concentrations in incoming air masses (i.e. air mass history), rather than cloud liquid water content (LWC) was the main factor controlling bulk solute concentrations at Mt. Schmücke. Droplet effective radius was found to be a somewhat better predictor for cloud water total ionic content (TIC) than LWC, even though no single explanatory variable can fully describe TIC (or solute concentration) variations in a simple functional relation due to the complex processes involved. Bulk concentrations typically agreed within a factor of 2 with co-located measurements of residual particle concentrations sampled by a counterflow virtual impactor (CV) and analysed by an aerosol mass spectrometer (AMS), with the deviations being mainly caused by systematic differences and limitations of the approaches (such as outgassing of dissolved gases during residual particle sampling). Scavenging efficiencies (SEs) of aerosol constituents were 0.56-0.94, 0.79-0.99, 0.71-98, and 0.67-0.92 for SO42-, NO3-, NH4+, and DOC, respectively, when calculated as event means with in-cloud data only. SEs estimated using data from an upwind site were substantially different in many cases, revealing the impact of gas-phase uptake (for volatile constituents) and mass losses across Mt. Schmücke likely due to physical processes such as droplet scavenging by trees and/or entrainment. Drop size-resolved cloud water concentrations of major ions SO42-, NO3-, and NH4+ revealed two main profiles: decreasing concentrations with increasing droplet size and "U"-shapes. In contrast, profiles of typical coarse particle mode minor ions were often increasing with increasing drop size, highlighting the importance of a species' particle concentration size distribution for the development of size-resolved solute concentration patterns. Concentration differences between droplet size classes were typically < 2 for major ions from the 3-stage collector and somewhat more pronounced from the 5-stage collector, while they were much larger for minor ions. Due to a better separation of droplet populations, the 5-stage collector was capable of resolving some features of solute size dependencies not seen in the 3-stage data, especially sharp concentration increases (up to a factor of 5-10) in the smallest droplets for many solutes.

Detecting dust hits at Enceladus, Saturn and beyond using CAPS / ELS data from Cassini

NASA Astrophysics Data System (ADS)

Vandegriff, J. D.; Stoneberger, P. J.; Jones, G.; Waite, J. H., Jr.

2016-12-01

It has recently been shown (1) that the impact of hypervelocity dust grains on the Cassini spacecraft can be detected by the Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument. For multiple Enceladus flybys, fine scale features in the lower energy regime of ELS energy spectra can be explained as short-duration, isotropic plasma clouds due to dust impacts. We have developed an algorithm for detecting these hypervelocity dust impacts, and the list of such impacts during Enceladus flybys will be presented. We also present preliminary results obtained when using the algorithm to search for dust impacts in other regions of Saturn's magnetosphere as well as in the solar wind. (1) Jones, Geraint, Hypervelocity dust impact signatures detected by Cassini CAPS-ELS in the Enceladus plume, MOP Meeting, June 1-5, 2015, Atlanta, GA

ULF geomagnetic activity effects on tropospheric temperature, specific humidity, and cloud cover in Antarctica, during 2003-2010

NASA Astrophysics Data System (ADS)

Regi, Mauro; Redaelli, Gianluca; Francia, Patrizia; De Lauretis, Marcello

2017-06-01

In the present study we investigated the possible relationship between the ULF geomagnetic activity and the variations of several atmospheric parameters. In particular, we compared the ULF activity in the Pc1-2 frequency band (100 mHz-5 Hz), computed from geomagnetic field measurements at Terra Nova Bay in Antarctica, with the tropospheric temperature T, specific humidity Q, and cloud cover (high cloud cover, medium cloud cover, and low cloud cover) obtained from reanalysis data set. The statistical analysis was conducted during the years 2003-2010, using correlation and Superposed Epoch Analysis approaches. The results show that the atmospheric parameters significantly change following the increase of geomagnetic activity within 2 days. These changes are evident in particular when the interplanetary magnetic field Bz component is oriented southward (Bz<0) and the By component duskward (By>0). We suggest that both the precipitation of electrons induced by Pc1-2 activity and the intensification of the polar cap potential difference, modulating the microphysical processes in the clouds, can affect the atmosphere conditions.

Trade-Wind Cloudiness and Climate

NASA Technical Reports Server (NTRS)

Randall, David A.

1997-01-01

Closed Mesoscale Cellular Convection (MCC) consists of mesoscale cloud patches separated by narrow clear regions. Strong radiative cooling occurs at the cloud top. A dry two-dimensional Bousinesq model is used to study the effects of cloud-top cooling on convection. Wide updrafts and narrow downdrafts are used to indicate the asymmetric circulations associated with the mesoscale cloud patches. Based on the numerical results, a conceptual model was constructed to suggest a mechanism for the formation of closed MCC over cool ocean surfaces. A new method to estimate the radioative and evaporative cooling in the entrainment layer of a stratocumulus-topped boundary layer has been developed. The method was applied to a set of Large-Eddy Simulation (LES) results and to a set of tethered-balloon data obtained during FIRE. We developed a statocumulus-capped marine mixed layer model which includes a parameterization of drizzle based on the use of a predicted Cloud Condensation Nuclei (CCN) number concentration. We have developed, implemented, and tested a very elaborate new stratiform cloudiness parameterization for use in GCMs. Finally, we have developed a new, mechanistic parameterization of the effects of cloud-top cooling on the entrainment rate.

Midwestern United States as seen from STS-58

NASA Image and Video Library

1993-10-30

STS058-102-018 (18 Oct-1 Nov 1993) --- A cloud-free, wide-angle view from above western Tennessee to the northern edge of Lake Michigan. The view extends from Saint Louis, Missouri near the lower left-hand corner, past Evansville, Indiana and Louisville, Kentucky to Cincinnati, Ohio. A range of hills covered by trees in Fall foliage extends from the Ohio River toward Lake Michigan, ending just southwest of Indianapolis, Indiana.

[Exacerbations of asthma in Guadeloupe (French West Indies) and volcanic eruption in Montserrat (70 km from Guadeloupe)].

PubMed

Cadelis, G; Tourres, R; Molinie, J; Petit, R H

2013-03-01

This study evaluates the impact of the ash cloud emitted in February 2010 during the eruption of the Soufrière Hill volcano of the island of Montserrat (70 km from Guadeloupe), on asthma exacerbations registered by the emergency hospital services in the archipelago of Guadeloupe in February 2010. We first recorded the clinical features and outcome of each adult patient admitted as an emergency with an acute asthma exacerbation during this period, then compared the admission rates for asthma exacerbation, concentrations of particulates and chemical pollutants, and climatic parameters before, during, and after exposure to the ash cloud. Then, using a generalized linear model defined by a Poisson regression, we calculated the risks related to these factors. There was an increase in acute asthma admissions during and after exposure to the ash cloud (2.44/day versus 5.6/day, P<0.003). PM10 (particles<10 microns) were the major particulate pollution episodes (mean: 223 μg/m(3)). Asthmatics admitted acutely during the period of pollution were young adults (35 [18-49] years old), and the majority had asthma classified as intermittent (57%, n=27). In multivariate analysis, PM10 were a risk factor for acute asthma presentations during this period (aRR 2.89, 95% [from 1.69 to 4.93]). This study describes the clinical data and outcome of adult patients admitted to emergency asthma exacerbation during the eruption of the Soufrière Hills Volcano in Montserrat and indicates that there was a significant impact of the ash plume on respiratory health, mainly in patients with intermittent asthma. Copyright © 2012 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Water clouds and dust aerosols observations with PFS MEX at Mars

NASA Astrophysics Data System (ADS)

Zasova, L.; Formisano, V.; Moroz, V.; Grassi, D.; Ignatiev, N.; Giuranna, M.; Hansen, G.; Blecka, M.; Ekonomov, A.; Lellouch, E.; Fonti, S.; Grigoriev, A.; Hirsch, H.; Khatuntsev, I.; Mattana, A.; Maturilli, A.; Moshkin, B.; Patsaev, D.; Piccioni, G.; Rataj, M.; Saggin, B.

2005-08-01

Observations of water ice clouds and dust are among the main scientific goals of the Planetary Fourier Spectrometer (PFS), a payload instrument of the European Mars Express mission. We report some results, obtained in three orbits: 37, 41 and 68. The temperature profile, and dust and water ice cloud opacities are retrieved from the thermal infrared (long-wavelength channel of PFS) in a self-consistent way using the same spectrum. Orographic ice clouds are identified above Olympus (orbit 37) and Ascraeus Mons (orbit 68). Both volcanoes were observed near noon at Ls=337° and 342°, respectively. The effective radius of ice particles is preliminary estimated as 1-3 μm, changing along the flanks. The corresponding visual opacity changes in the interval 0.2-0.4 above Olympus and 0.1-0.6 above Ascraeus Mons. In the case of Ascraeus Mons, the ice clouds were observed mainly above the Southern flank of the volcano with maximum opacity near the summit. In the case of Olympus, the clouds were found above both sides of the top. A different type of ice cloud is observed at latitudes above 50°N (orbit 68) in the polar hood: the effective particle radius is estimated to be 4 μm. Below the 1 mb level an inversion in the temperature profiles is found with maximum temperature at around 0.6 mb. Along orbit 68 it appears above Alba Patera, then it increases to the north and decreases above the CO 2 polar cap. Beginning from latitude 20°S above Tharsis (orbit 68), the ice clouds and dust contribute equally to the spectral shape. Further on, the ice clouds are found everywhere along orbit 68 up to the Northern polar cap, except the areas between the Northern flank of Ascraeus Mons (below 10 km) and the edge of Alba Patera. Orbit 41 is shifted from the orbit 68 by roughly 180° longitude and passes through Hellas. Ice clouds are not visible in this orbit at latitudes below 80°S. The dust opacity is anticorrelated with the surface altitude. From 70°S to 25°N latitude the vertical dust distribution follows an exponential law with a scale height of 11.5±0.5 km, which corresponds to the gaseous scale height near noon and indicates a well-mixed condition. The 9 μm dust opacity, reduced to zero surface altitude, is found to be 0.25±0.05, which corresponds to a visual opacity of 0.5-0.7 (depending on the particle size).

Analysis of Rapidly Developing Low Cloud Ceilings in a Stable Environment

NASA Technical Reports Server (NTRS)

Bauman, William H., III; Barrett, Joe H., III; Case, Jonathan L.; Wheeler, Mark M.; Baggett, G. Wayne

2006-01-01

Forecasters at the Space Meteorology Group (SMG) issue 30 to 90 minute forecasts for low cloud ceilings at the Space Shuttle Landing Facility (TTS) to support Space Shuttle landings. Mission verification statistics have shown ceilings to be the number one forecast challenge for SMG. More specifically, forecasters at SMG are concerned with any rapidly developing clouds/ceilings below 8000 ft in a stable, capped thermodynamic environment. Therefore, the Applied Meteorology Unit (AMU) was tasked to examine archived events of rapid stable cloud formation resulting in ceilings below 8000 ft, and document the atmospheric regimes favoring this type of cloud development. The AMU examined the cool season months of November to March during the years of 1993-2003 for days that had low-level inversions and rapid, stable low cloud formation that resulted in ceilings violating the Space Shuttle Flight Rules. The AMU wrote and modified existing code to identify inversions from the morning (-10 UTC) Cape Canaveral, FL rawinsonde (XMR) during the cool season and output pertinent sounding information. They parsed all days with cloud ceilings below 8000 ft at TTS, forming a database of possible rapidly-developing low ceiling events. Days with precipitation or noticeable fog burn-off situations were excluded from the database. In the first phase of this work, only the daytime hours were examined for possible ceiling development events since low clouds are easier to diagnose with visible satellite imagery. Phase II of this work includes expanding the database to include nighttime cases which is underway as this abstract is being written. For the nighttime cases, the AMU will analyze both the 00 UTC soundings and the 10 UTC soundings to examine those data for the presence of a low-level inversion. The 00 UTC soundings will probably not have a surface-based inversion, but the presence of inversions or "neutral" layers aloft and below 8,000 ft will most likely help define the stable regime, being a thermodynamically "capped" environment. Occurrences of elevated low-level inversions or stable layers will be highlighted in conjunction with nights that experienced a possible development or onset of cloud ceilings below 8,000 ft. Using these criteria to narrow down the database, the AMU will then use archived IR satellite imagery for these possible events. This presentation summarizes the composite meteorological conditions for 20 daytime event days with rapid low cloud ceiling formation and 48 non-events days consisting of advection or widespread low cloud ceilings and describes two sample cases of daytime rapidly-developing low cloud ceilings. The authors will also summarize the work from the nighttime cases and describe a representative sample case from this data set.

Clouds in the Martian Atmosphere

NASA Astrophysics Data System (ADS)

Määttänen, Anni; Montmessin, Franck

2018-01-01

Although resembling an extremely dry desert, planet Mars hosts clouds in its atmosphere. Every day somewhere on the planet a part of the tiny amount of water vapor held by the atmosphere can condense as ice crystals to form cirrus-type clouds. The existence of water ice clouds has been known for a long time, and they have been studied for decades, leading to the establishment of a well-known climatology and understanding of their formation and properties. Despite their thinness, they have a clear impact on the atmospheric temperatures, thus affecting the Martian climate. Another, more exotic type of clouds forms as well on Mars. The atmospheric temperatures can plunge to such frigid values that the major gaseous component of the atmosphere, CO2, condenses as ice crystals. These clouds form in the cold polar night where they also contribute to the formation of the CO2 ice polar cap, and also in the mesosphere at very high altitudes, near the edge of space, analogously to the noctilucent clouds on Earth. The mesospheric clouds are a fairly recent discovery and have put our understanding of the Martian atmosphere to a test. On Mars, cloud crystals form on ice nuclei, mostly provided by the omnipresent dust. Thus, the clouds link the three major climatic cycles: those of the two major volatiles, H2O and CO2; and that of dust, which is a major climatic agent itself.

Telescopic observations - Visual, photographic, polarimetric. [of planet Mars

NASA Technical Reports Server (NTRS)

Martin, Leonard J.; James, Philip B.; Dollfus, Audouin; Iwasaki, Kyosuke; Beish, Jeffrey D.

1992-01-01

The paper divides the high points of telescopic observations of Mars into three time periods: historical, missions support (recent), and present. Particular attention is given to visual and photographic observations, with brief discussions of spectroscopic and polarization studies. Major topics of Martian phenomena included are albedo features, polar caps, dust storms, and white clouds. The interannual variability of the recessions of seasonal polar caps has been compared to dust storm activity, but this relationship remains uncertain. Only a very limited number of canals can be related to markings on the Viking images. The remainder are argued to be optical illusions created by observers pushing their perceived resolution beyond practical limits.

MECA Symposium on Mars: Evolution of its Climate and Atmosphere

NASA Technical Reports Server (NTRS)

Baker, Victor (Editor); Carr, Michael (Editor); Fanale, Fraser (Editor); Greeley, Ronald (Editor); Haberle, Robert (Editor); Leovy, Conway (Editor); Maxwell, Ted (Editor)

1987-01-01

The geological, atmospheric, and climatic history of Mars is explored in reviews and reports of recent observational and interpretive investigations. Topics addressed include evidence for a warm wet climate on early Mars, volatiles on Earth and on Mars, CO2 adsorption on palagonite and its implications for Martian regolith partitioning, and the effect of spatial resolution on interpretations of Martian subsurface volatiles. Consideration is given to high resolution observations of rampart craters, ring furrows in highland terrains, the interannual variability of the south polar cap, telescopic observations of the north polar cap and circumpolar clouds, and dynamical modeling of a planetary wave polar warming mechanism.

Full-Circle Vista With a Linear Shaped Martian Sand Dune

NASA Image and Video Library

2017-02-27

The left side of this 360-degree panorama from NASA's Curiosity Mars rover shows the long rows of ripples on a linear shaped dune in the Bagnold Dune Field on the northwestern flank of Mount Sharp. The view is a mosaic of images taken with Curiosity's Navigation Camera (Navcam) on Feb. 5, 2017, during the 1,601st Martian day, or sol, of the rover's work on Mars. The view is centered toward west-southwest, with east-southeast on either end. A capped mound called "Ireson Hill" is on the right. http://photojournal.jpl.nasa.gov/catalog/PIA21268

Computational analysis of PET by AIBL (CapAIBL): a cloud-based processing pipeline for the quantification of PET images

NASA Astrophysics Data System (ADS)

Bourgeat, Pierrick; Dore, Vincent; Fripp, Jurgen; Villemagne, Victor L.; Rowe, Chris C.; Salvado, Olivier

2015-03-01

With the advances of PET tracers for β-Amyloid (Aβ) detection in neurodegenerative diseases, automated quantification methods are desirable. For clinical use, there is a great need for PET-only quantification method, as MR images are not always available. In this paper, we validate a previously developed PET-only quantification method against MR-based quantification using 6 tracers: 18F-Florbetaben (N=148), 18F-Florbetapir (N=171), 18F-NAV4694 (N=47), 18F-Flutemetamol (N=180), 11C-PiB (N=381) and 18F-FDG (N=34). The results show an overall mean absolute percentage error of less than 5% for each tracer. The method has been implemented as a remote service called CapAIBL (http://milxcloud.csiro.au/capaibl). PET images are uploaded to a cloud platform where they are spatially normalised to a standard template and quantified. A report containing global as well as local quantification, along with surface projection of the β-Amyloid deposition is automatically generated at the end of the pipeline and emailed to the user.

South Polar Cap Erosion and Aprons

NASA Technical Reports Server (NTRS)

2000-01-01

This scene is illuminated by sunlight from the upper left.

While Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have shown that the north and south polar cap surfaces are very different from each other, one thing that the two have in common is that they both seem to have been eroded. Erosion in the north appears mostly to come in the form of pits from which ice probably sublimed to vapor and was transported away from the polar cap by wind. Erosion in the south takes on a wider range of possible processes that include collapse, slumping and mass-movement on slopes, and probably sublimation. Among the landforms created by these process on the south polar cap are the 'aprons' that surround mesas and buttes of remnant layers such as the two almost triangular features in the lower quarter of this image. The upper slopes of the two triangular features show a stair-stepped pattern that suggest these hills are layered.

This image shows part of the south polar residual cap near 86.9oS, 78.5oW, and covers an area approximately 1.2 by 1.0 kilometers (0.7 x 0.6 miles) in size. The image has a resolution of 2.2 meters per pixel. The picture was taken on September 11, 1999.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Infrared Image of Low Clouds on Venus

NASA Technical Reports Server (NTRS)

1993-01-01

This false-color image is a near-infrared map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft as it approached the planet's night side on February 10, 1990. Bright slivers of sunlit high clouds are visible above and below the dark, glowing hemisphere. The spacecraft is about 100,000 kilometers (60,000 miles) above the planet. An infrared wavelength of 2.3 microns (about three times the longest wavelength visible to the human eye) was used. The map shows the turbulent, cloudy middle atmosphere some 50-55 kilometers (30- 33 miles) above the surface, 10-16 kilometers or 6-10 miles below the visible cloudtops. The red color represents the radiant heat from the lower atmosphere (about 400 degrees Fahrenheit) shining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. This cloud layer is at about -30 degrees Fahrenheit, at a pressure about 1/2 Earth's surface atmospheric pressure. Near the equator, the clouds appear fluffy and blocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude.

Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) Final Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, R.

2016-01-01

The extensive coverage of low clouds over the subtropical eastern oceans greatly impacts the current climate. In addition, the response of low clouds to changes in atmospheric greenhouse gases and aerosols is a major source of uncertainty, which thwarts accurate prediction of future climate change. Low clouds are poorly simulated in climate models, partly due to inadequate long-term simultaneous observations of their macrophysical and microphysical structure, radiative effects, and associated aerosol distribution in regions where their impact is greatest. The thickness and extent of subtropical low clouds is dependent on tight couplings between surface fluxes of heat and moisture, radiativemore » cooling, boundary layer turbulence, and precipitation (much of which evaporates before reaching the ocean surface and is closely connected to the abundance of cloud condensation nuclei). These couplings have been documented as a result of past field programs and model studies. However, extensive research is still required to achieve a quantitative understanding sufficient for developing parameterizations, which adequately predict aerosol indirect effects and low cloud response to climate perturbations. This is especially true of the interactions between clouds, aerosol, and precipitation. These processes take place in an ever-changing synoptic environment that can confound interpretation of short time period observations.« less

Sedimentary structures and stratal geometries at the foothills of Mount Sharp: their role in paleoenvironmental interpretation

NASA Astrophysics Data System (ADS)

Gupta, S.; Rubin, D. M.; Sumner, D. Y.; Grotzinger, J. P.; Lewis, K. W.; Stack, K.; Kah, L. C.; Banham, S.; Edgett, K. S.

2015-12-01

The Mars Science Laboratory Curiosity rover has been exploring sedimentary rocks at the foothills of Mount Sharp since August 2014. Robust interpretation of the paleoenvironmental contexts requires detailed facies analysis of these rocks including analysis and interpretation of sedimentary structures and sediment body geometries. Here, we describe some of the detailed sedimentary structures and sedimentary geometries observed by Curiosity between the Pahrump_Hills field site and its current location at Marias Pass. The Pahrump Hills sedimentary section comprises a succession dominated by finely laminated mudstones of the Murray formation that are interpreted to have been deposited in an ancient lake within Gale crater. Toward the top of the Pahump Hills succession, we observe the appearance of coarser-grained sandstones that are interstratified within the lacustrine mudstones. These sandstones that include Whale Rock and Newspaper Rock show lenticular geometries, and are pervasively cross-stratified. These features indicate that currents eroded shallow scours in the lake beds that were then infilled by deposition from migrating subaqueous dunes. The paleoenvironmental setting may represent either a gullied delta front setting or one in which lake level fall caused fluvial erosion and infilling of the shallow scours. Since leaving Pahrump_Hills, Curiosity has imaged extensive exposures of strata that are partly correlative with and stratigraphically overlie the uppermost part of the Pahrump section. Isolated cross-bedded sandstones and possible interstratified conglomerates beds occur within Murray formation mudstones. Capping sandstones with a likely variety of environmental contexts overlie mudstones. Where imaged in detail, sedimentary structures, such as trough-cross bedding and possible eolian pinstriping, provide constraints on plausible sedimentary processes and bounds on depositional setting.

CO2 cycle

USGS Publications Warehouse

Titus, Timothy N.; Byrne, Shane; Colaprete, Anthony; Forget, Francois; Michaels, Timothy I.; Prettyman, Thomas H.

2017-01-01

This chapter discusses the use of models, observations, and laboratory experiments to understand the cycling of CO2 between the atmosphere and seasonal Martian polar caps. This cycle is primarily controlled by the polar heat budget, and thus the emphasis here is on its components, including solar and infrared radiation, the effect of clouds (water- and CO2-ice), atmospheric transport, and subsurface heat conduction. There is a discussion about cap properties including growth and regression rates, albedos and emissivities, grain sizes and dust and/or water-ice contamination, and curious features like cold gas jets and araneiform (spider-shaped) terrain. The nature of the residual south polar cap is discussed as well as its long-term stability and ability to buffer atmospheric pressures. There is also a discussion of the consequences of the CO2 cycle as revealed by the non-condensable gas enrichment observed by Odyssey and modeled by various groups.

Laboratory Studies of the Cloud Droplet Activation Properties and Corresponding Chemistry of Saline Playa Dust.

PubMed

Gaston, Cassandra J; Pratt, Kerri A; Suski, Kaitlyn J; May, Nathaniel W; Gill, Thomas E; Prather, Kimberly A

2017-02-07

Playas emit large quantities of dust that can facilitate the activation of cloud droplets. Despite the potential importance of playa dusts for cloud formation, most climate models assume that all dust is nonhygroscopic; however, measurements are needed to clarify the role of dusts in aerosol-cloud interactions. Here, we report measurements of CCN activation from playa dusts and parameterize these results in terms of both κ-Köhler theory and adsorption activation theory for inclusion in atmospheric models. κ ranged from 0.002 ± 0.001 to 0.818 ± 0.094, whereas Frankel-Halsey-Hill (FHH) adsorption parameters of A FHH = 2.20 ± 0.60 and B FHH = 1.24 ± 0.14 described the water uptake properties of the dusts. Measurements made using aerosol time-of-flight mass spectrometry (ATOFMS) revealed the presence of halite, sodium sulfates, and sodium carbonates that were strongly correlated with κ underscoring the role that mineralogy, including salts, plays in water uptake by dust. Predictions of κ made using bulk chemical techniques generally showed good agreement with measured values. However, several samples were poorly predicted suggesting that chemical heterogeneities as a function of size or chemically distinct particle surfaces can determine the hygroscopicity of playa dusts. Our results further demonstrate the importance of dust in aerosol-cloud interactions.

Pyroclastic flows generated by gravitational instability of the 1996-97 lava dome of Soufriere Hills Volcano, Montserrat

USGS Publications Warehouse

Cole, P.D.; Calder, E.S.; Druitt, T.H.; Hoblitt, R.; Robertson, R.; Sparks, R.S.J.; Young, S.R.

1998-01-01

Numerous pyroclastic flows were produced during 1996-97 by collapse of the growing andesitic lava dome at Soufriere Hills Volcano, Montserrat. Measured deposit volumes from these flows range from 0.2 to 9 ?? 106 m3. Flows range from discrete, single pulse events to sustained large scale dome collapse events. Flows entered the sea on the eastern and southern coasts, depositing large fans of material at the coast. Small runout distance (<1 km) flows had average flow front velocities in the order of 3-10 m/s while flow fronts of the larger runout distance flows (up to 6.5 km) advanced in the order of 15-30 m/s. Many flows were locally highly erosive. Field relations show that development of the fine grained ash cloud surge component was enhanced during the larger sustained events. Periods of elevated pyroclastic flow productivity and sustained dome collapse events are linked to pulses of high magma extrusion rates.Numerous pyroclastic flows were produced during 1996-97 by collapse of the growing andesitic lava dome at Soufriere Hills Volcano, Montserrat. Measured deposit volumes from these flows range from 0.2 to 9??106 m3. Flows range from discrete, single pulse events to sustained large scale dome collapse events. Flows entered the sea on the eastern and southern coasts, depositing large fans of material at the coast. Small runout distance (<1 km) flows had average flow front velocities in the order of 3-10 m/s while flow fronts of the larger runout distance flows (up to 6.5 km) advanced in the order of 15-30 m/s. Many flows were locally highly erosive. Field relations show that development of the fine grained ash cloud surge component was enhanced during the larger sustained events. Periods of elevated dome pyroclastic flow productivity and sustained collapse events are linked to pulses of high magma extrusion rates.

Possible recent and ancient glacial ice flow in the south polar region of Mars

NASA Technical Reports Server (NTRS)

Kargel, J. S.

1992-01-01

Martian polar science began almost as soon as small telescopes were trained on the planet. The seasonal expansion and contraction of the polar caps and their high albedoes led most astronomers to think that water ice is the dominant constituent. In 1911 Lowell perceived a bluish band around the retreating edge of the polar caps, and interpreted it as water from melting polar ice and seasonal snow. An alternative idea in his time was that the polar caps consist of frozen carbonic acid. Lowell rejected the carbonic acid hypothesis on account of his blue band. He also pointed out that carbonic acid would sublimate rather than melt at confining pressures near and below one bar, hence, carbonic acid could not account for the blue band. In comparing Lowell's theories with today's knowledge, it is recognized that (1) sublimation is mainly responsible for the growth and contraction of Mars' polar caps, (2) carbon dioxide is a major component of the southern polar cap, and (3) Lowell's blue band was probably seasonal dust and/or clouds. Geomorphic evidence that glacial ice and glacial melt waters once flowed over broad areas of the southern polar region. Two aspects of the south polar region suggest possible glacial processes during two distinct eras in Mars' history.

Red Cloud’s War: An Insurgency Case Study for Modern Times

DTIC Science & Technology

2011-03-16

region. All these tribes were master horseman , and over time became skilled and fearsome mounted warriors. It is important to note how much different...much of the land as ”sacred ground” to be defended to the death . The Powder River Country from the Big Horn Mountains to the Black Hills loomed large...too inviting for the hostiles, and running this daily gauntlet of death resulted in many casualties. On the other hand, one terrain advantage for

Overview for the reanalysis of Mariner 9 UV spectrometer data for ozone, cloud, and dust abundances, and their interaction over climate timescales

NASA Technical Reports Server (NTRS)

Lindner, Bernhard Lee

1992-01-01

Mariner 9 UV spectrometer data were reinverted for the ozone abundance, cloud abundance, dust abundance, and polar-cap albedo. The original reduction of the spectra ignored the presence of atmospheric dust and clouds, even though their abundance is substantial and can mask appreciable amounts of ozone if not accounted for (Lindner, 1988). The Mariner 9 ozone data has been used as a benchmark in all theoretical models of atmospheric composition, escape, and photochemistry. A second objective is to examine the data for the interrelationship of the ozone cycle, dust cycle, and cloud cycle, on an annual, inter-annual, and climatic basis, testing predictions by Lindner (1988). This also has implications for many terrestrial ozone studies, such as the ozone hole, acid rain, and ozone-smog. A third objective is to evaluate the efficacy of the reflectance spectroscopy technique at retrieving the ozone abundance on Mars. This would be useful for planning ozone observations on future Mars missions or the terrestrial troposphere.

Characteristics of ionospheric electron density profiles in the auroral and polar cap regions from long-term incoherent scatter radar observations

NASA Astrophysics Data System (ADS)

Jee, G.; Kim, E.; Kwak, Y. S.; Kim, Y.; Kil, H.

2017-12-01

We investigate the climatological characteristics of the ionospheric electron density profiles in the auroral and polar cap regions in comparison with the mid-latitude ionosphere using incoherent scatter radars (ISR) observations from Svalbard (78.15N, 16.05E), Tromso (69.59N, 19.23E), and Millstone Hill (42.6N, 288.5E) during a period of 1995 - 2015. Diurnal variations of electron density profiles from 100 to 500 km are compared among the three radar observations during equinox, summer and winter solstice for different solar and geomagnetic activities. Also investigated are the physical characteristics of E-region and F-region peak parameters of electron density profiles in the auroral and polar cap regions, which are significantly different from the mid-latitude ionosphere. In the polar ionosphere, the diurnal variations of density profiles are extremely small in summer hemisphere. Semiannual anomaly hardly appears for all latitudes, but winter anomaly occurs at mid-latitude and auroral ionospheres for high solar activity. Nighttime density becomes larger than daytime density in the winter polar cap ionosphere for high solar activity. The E-region peak is very distinctive in the nighttime auroral region and the peak height is nearly constant at about 110 km for all conditions. Compared with the F-region peak density, the E-region peak density does not change much with solar activity. Furthermore, the E-region peak density can be even larger than F-region density for low solar activity in the auroral region, particularly during disturbed condition.

CLaMS-Ice: Large-scale cirrus cloud simulations in comparison with observations

NASA Astrophysics Data System (ADS)

Costa, Anja; Rolf, Christian; Grooß, Jens-Uwe; Spichtinger, Peter; Afchine, Armin; Spelten, Nicole; Dreiling, Volker; Zöger, Martin; Krämer, Martina

2016-04-01

Cirrus clouds are an element of uncertainty in the climate system and have received increasing attention since the last IPCC reports. The interactions of different freezing mechanisms, sedimentation rates, updraft velocity fluctuations and other factors that determine the formation and evolution of those clouds is still not fully understood. Thus, a reliable representation of cirrus clouds in models representing real atmospheric conditions is still a challenging task. At last year's EGU, Rolf et al. (2015) introduced the new large-scale microphysical cirrus cloud model CLaMS-Ice: based on trajectories calculated with CLaMS (McKenna et al., 2002 and Konopka et al. 2007), it simulates the development of cirrus clouds relying on the cirrus bulk model by Spichtinger and Gierens (2009). The qualitative agreement between CLaMS-Ice simulations and observations could be demonstrated at that time. Now we present a detailed quantitative comparison between standard ECMWF products, CLaMS-Ice simulations, and in-situ measurements obtained during the ML-Cirrus campaign 2014. We discuss the agreement of the parameters temperature (observational data: BAHAMAS), relative humidity (SHARC), cloud occurrence, cloud particle concentration, ice water content and cloud particle radii (all NIXE-CAPS). Due to the precise trajectories based on ECMWF wind and temperature fields, CLaMS-Ice represents the cirrus cloud vertical and horizontal coverage more accurately than the ECMWF ice water content (IWC) fields. We demonstrate how CLaMS-Ice can be used to evaluate different input settings (e.g. amount of ice nuclei, freezing thresholds, sedimentation settings) that lead to cirrus clouds with the microphysical properties observed during ML-Cirrus (2014).

Glaciotectonic deformation and reinterpretation of the Worth Point stratigraphic sequence: Banks Island, NT, Canada

NASA Astrophysics Data System (ADS)

Vaughan, Jessica M.; England, John H.; Evans, David J. A.

2014-05-01

Hill-hole pairs, comprising an ice-pushed hill and associated source depression, cluster in a belt along the west coast of Banks Island, NT. Ongoing coastal erosion at Worth Point, southwest Banks Island, has exposed a section (6 km long and ˜30 m high) through an ice-pushed hill that was transported ˜ 2 km from a corresponding source depression to the southeast. The exposed stratigraphic sequence is polydeformed and comprises folded and faulted rafts of Early Cretaceous and Late Tertiary bedrock, a prominent organic raft, Quaternary glacial sediments, and buried glacial ice. Three distinct structural domains can be identified within the stratigraphic sequence that represent proximal to distal deformation in an ice-marginal setting. Complex thrust sequences, interfering fold-sets, brecciated bedrock and widespread shear structures superimposed on this ice-marginally deformed sequence record subsequent deformation in a subglacial shear zone. Analysis of cross-cutting relationships within the stratigraphic sequence combined with OSL dating indicate that the Worth Point hill-hole pair was deformed during two separate glaciotectonic events. Firstly, ice sheet advance constructed the hill-hole pair and glaciotectonized the strata ice-marginally, producing a proximal to distal deformation sequence. A glacioisostatically forced marine transgression resulted in extensive reworking of the strata and the deposition of a glaciomarine diamict. A readvance during this initial stage redeformed the strata in a subglacial shear zone, overprinting complex deformation structures and depositing a glaciotectonite ˜20 m thick. Outwash channels that incise the subglacially deformed strata record a deglacial marine regression, whereas aggradation of glaciofluvial sand and gravel infilling the channels record a subsequent marine transgression. Secondly, a later, largely non-erosive ice margin overrode Worth Point, deforming only the most surficial units in the section and depositing a capping till. The investigation of the Worth Point stratigraphic sequence provides the first detailed description of the internal architecture of a polydeformed hill-hole pair, and as such provides an insight into the formation and evolution of an enigmatic landform. Notably, the stratigraphic sequence documents ice-marginal and subglacial glaciotectonics in permafrost terrain, as well as regional glacial and relative sea level histories. The reinterpreted stratigraphy fundamentally rejects the long-established paleoenvironmental history of Worth Point that assumed a simple ‘layer-cake’ stratigraphy including the type-site for an organically rich, preglacial interval (Worth Point Fm).

Clouds, Aerosols, and Precipitation in the Marine Boundary Layer: An Arm Mobile Facility Deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.

The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulusmore » and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1- 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging. The data from at Graciosa are being compared with short-range forecasts made a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.« less

Clouds, aerosol, and precipitation in the Marine Boundary Layer: An ARM mobile facility deployment

DOE PAGES

Wood, Robert; Luke, Ed; Wyant, Matthew; ...

2014-04-27

The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols, and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulusmore » and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.« less

Clouds, Aerosols, and Precipitation in the Marine Boundary Layer: An Arm Mobile Facility Deployment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.

The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) 38 deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) 39 comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric 40 Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is 41 to gain improved understanding of the interactions of clouds, aerosols and precipitation in the 42 marine boundary layer. 43 Graciosa Island straddles the boundary between the subtropics and midlatitudes in the 44 Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and 45 cloudiness conditions. Lowmore » clouds are the dominant cloud type, with stratocumulus and cumulus 46 occurring regularly. Approximately half of all clouds contained precipitation detectable as radar 47 echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-48 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide 49 range of aerosol conditions was sampled during the deployment consistent with the diversity of 50 sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way 51 interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation 52 and cloud radiative properties while being controlled in part by precipitation scavenging. 53 The data from at Graciosa are being compared with short-range forecasts made a variety 54 of models. A pilot analysis with two climate and two weather forecast models shows that they 55 reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, 56 but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to 57 be a long-term ARM site that became operational in October 2013.« less

Ice dynamics of the Allan Hills meteorite concentration sites revealed by satellite aperture radar interferometry

NASA Astrophysics Data System (ADS)

Coren, F.; Delisle, G.; Sterzai, P.

2003-09-01

The ice flow conditions of a 100 x 100 km area of Victoria Land, Antarctica were analyzed with the synthetic aperture radar (SAR) technique. The area includes a number of meteorite concentration sites, in particular the Allan Hills ice fields. Regional ice flow velocities around the Mid- western and Near-western ice fields and the Allan Hills main ice field are shown to be 2.5 m yr-1. These sites are located on a horseshoe-shaped area that bounds an area characterized by higher ice flow velocities of up to 5 m yr-1. Meteorite find locations on the Elephant Moraine are located in this "high ice flow" area. The SAR derived digital elevation model (DEM) shows atypical low surface slopes for Antarctic conditions, which are the cause for the slow ice movements. Numerous ice rises in the area are interpreted to cap sub-ice obstacles, which were formed by tectonic processes in the past. The ice rises are considered to represent temporary features, which develop only during warm stages when the regional ice stand is lowered. Ice depressions, which develop in warm stages on the lee side of ice rises, may act as the sites of temporary build-up of meteorite concentrations, which turn inoperative during cold stages when the regional ice level rises and the ice rises disappear. Based on a simplified ice flow model, we argue that the regional ice flow in cold stages is reduced by a factor of at least 3.

Mars: Atmosphere

NASA Astrophysics Data System (ADS)

Moroz, V.; Murdin, P.

2001-07-01

The atmosphere of MARS is much thinner than the terrestrial one. However, even the simplest visual telescopic observations show a set of atmospheric events such as seasonal exchange of material between polar caps, temporal appearance of clouds and changes of visibility of dark regions on the disk of the planet. In 1947 the prominent CO2 bands in the near-infrared part of the Martian spectrum were...

AFGL Fiscal Year 1989. Air Force Technical Objectives Document

DTIC Science & Technology

1988-10-01

analyzing and forecasting atmospheric parameters. The critical technologies are cloud and precipitation effects, atmospheric boundary effects, climatology for...on the morphology and dynamics of auroral electron and ion precipitation using existing and future satellite data bases. The research will specify the...other ground based diagnostics. In the transport and particle precipitation dominated regions of polar cap, oval, and trough, research efforts are

KSC-99pc04

NASA Image and Video Library

1999-01-03

KENNEDY SPACE CENTER, FLA. -- Amid clouds of exhaust and into a gray-clouded sky , a Boeing Delta II expendable launch vehicle lifts off with NASA's Mars Polar Lander at 3:21:10 p.m. EST from Launch Complex 17B, Cape Canaveral Air Station. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

Soil information system of Arunachal Pradesh in a GIS environment for land use planning

NASA Astrophysics Data System (ADS)

Maji, Amal K.; Nayak, Dulal C.; Krishna, Nadimpalli, , DR; Srinivas, Challa V.; Kamble, Kalpana; Reddy, Gangalakunta P. Obi; Velayutham, Mariappan

Arunachal Pradesh, the largest mountainous state of India, is situated in the northeastern part of the Himalayan region and characterized by high annual rainfall, forest vegetation and diversity in soils. Information on the soils of the state is essential for scientific land use planning and sustainable production. A soil resource inventory and subsequent database creation for thematic mapping using a Geographical Information System (GIS) is presented in this paper. Physiographically, Arunachal Pradesh can be divided into four distinct zones: snow-capped mountains (5500 m amsl); lower Himalayan ranges (3500 m amsl); the sub-Himalayan Siwalik hills (700 m amsl); and the eastern Assam plains. Soils occurring in these physiographic zones are Inceptisols (37 percent), Entisols (35 percent), Ultisols (14 percent) and Alfisols (0.5 percent). The remaining soils can be classed as miscellaneous. Soil resource inventory studies show that the soils of the warm perhumid eastern Himalayan ecosystem, with a 'thermic' temperature regime, are Inceptisols and Entisols; and that they are highly acidic in nature. Soils of the warm perhumid Siwalik hill ecosystem, with a 'hyperthermic' temperature regime, are also Entisols and Inceptisols with a high to moderate acidic condition. The dominant soils of the northeastern Purvachal hill ecosystem, with 'hyperthermic' and 'thermic' temperature regimes, are Ultisols and Inceptisols. Inceptisols and Entisols are the dominant soils in the hot and humid plain ecosystem. Steeply sloping landform and high rainfall are mainly responsible for a high erosion hazard in the state. The soil erosion map indicates that very severe (20 percent of TGA) to severe (25 percent of TGA) soil erosion takes place in the warm per-humid zone, whereas, moderate erosion takes place in the Siwalik hills and hot, humid plain areas. This is evident from the soil depth class distribution of Arunachal Pradesh, which shows that shallow soils cover 20 percent of the TGA of the state. Most of the state is covered by hills and agricultural practices are limited to valley regions. However, the soils of other physiographic zones (lower altitudinal, moderately hilly terrain) provide scope for plantations, such as orange, banana and tea plantations.

Using In Situ Observations and Satellite Retrievals to Constrain Large-Eddy Simulations and Single-Column Simulations: Implications for Boundary-Layer Cloud Parameterization in the NASA GISS GCM

NASA Astrophysics Data System (ADS)

Remillard, J.

2015-12-01

Two low-cloud periods from the CAP-MBL deployment of the ARM Mobile Facility at the Azores are selected through a cluster analysis of ISCCP cloud property matrices, so as to represent two low-cloud weather states that the GISS GCM severely underpredicts not only in that region but also globally. The two cases represent (1) shallow cumulus clouds occurring in a cold-air outbreak behind a cold front, and (2) stratocumulus clouds occurring when the region was dominated by a high-pressure system. Observations and MERRA reanalysis are used to derive specifications used for large-eddy simulations (LES) and single-column model (SCM) simulations. The LES captures the major differences in horizontal structure between the two low-cloud fields, but there are unconstrained uncertainties in cloud microphysics and challenges in reproducing W-band Doppler radar moments. The SCM run on the vertical grid used for CMIP-5 runs of the GCM does a poor job of representing the shallow cumulus case and is unable to maintain an overcast deck in the stratocumulus case, providing some clues regarding problems with low-cloud representation in the GCM. SCM sensitivity tests with a finer vertical grid in the boundary layer show substantial improvement in the representation of cloud amount for both cases. GCM simulations with CMIP-5 versus finer vertical gridding in the boundary layer are compared with observations. The adoption of a two-moment cloud microphysics scheme in the GCM is also tested in this framework. The methodology followed in this study, with the process-based examination of different time and space scales in both models and observations, represents a prototype for GCM cloud parameterization improvements.

Classification of Arctic, Mid-Latitude and Tropical Clouds in the Mixed-Phase Temperature Regime

NASA Astrophysics Data System (ADS)

Costa, Anja; Afchine, Armin; Luebke, Anna; Meyer, Jessica; Dorsey, James R.; Gallagher, Martin W.; Ehrlich, André; Wendisch, Manfred; Krämer, Martina

2016-04-01

The degree of glaciation and the sizes and habits of ice particles formed in mixed-phase clouds remain not fully understood. However, these properties define the mixed clouds' radiative impact on the Earth's climate and thus a correct representation of this cloud type in global climate models is of importance for an improved certainty of climate predictions. This study focuses on the occurrence and characteristics of two types of clouds in the mixed-phase temperature regime (238-275K): coexistence clouds (Coex), in which both liquid drops and ice crystals exist, and fully glaciated clouds that develop in the Wegener-Bergeron-Findeisen regime (WBF clouds). We present an extensive dataset obtained by the Cloud and Aerosol Particle Spectrometer NIXE-CAPS, covering Arctic, mid-latitude and tropical regions. In total, we spent 45.2 hours within clouds in the mixed-phase temperature regime during five field campaigns (Arctic: VERDI, 2012 and RACEPAC, 2014 - Northern Canada; mid-latitude: COALESC, 2011 - UK and ML-Cirrus, 2014 - central Europe; tropics: ACRIDICON, 2014 - Brazil). We show that WBF and Coex clouds can be identified via cloud particle size distributions. The classified datasets are used to analyse temperature dependences of both cloud types as well as range and frequencies of cloud particle concentrations and sizes. One result is that Coex clouds containing supercooled liquid drops are found down to temperatures of -40 deg C only in tropical mixed clouds, while in the Arctic and mid-latitudes no liquid drops are observed below about -20 deg C. In addition, we show that the cloud particles' aspherical fractions - derived from polarization signatures of particles with diameters between 20 and 50 micrometers - differ significantly between WBF and Coex clouds. In Coex clouds, the aspherical fraction of cloud particles is generally very low, but increases with decreasing temperature. In WBF clouds, where all cloud particles are ice, about 20-40% of the cloud particles are nevertheless classified as spherical for all temperatures, possibly indicating columnar ice crystals (see Järvinen et al, submitted to JAS 2016).

Central American biomass burning smoke can increase tornado severity in the U.S.

NASA Astrophysics Data System (ADS)

Saide, P. E.; Spak, S. N.; Pierce, R. B.; Otkin, J. A.; Schaack, T. K.; Heidinger, A. K.; Silva, A. M.; Kacenelenbogen, M.; Redemann, J.; Carmichael, G. R.

2015-02-01

Tornadoes in the Southeast and central U.S. are episodically accompanied by smoke from biomass burning in central America. Analysis of the 27 April 2011 historical tornado outbreak shows that adding smoke to an environment already conducive to severe thunderstorm development can increase the likelihood of significant tornado occurrence. Numerical experiments indicate that the presence of smoke during this event leads to optical thickening of shallow clouds while soot within the smoke enhances the capping inversion through radiation absorption. The smoke effects are consistent with measurements of clouds and radiation before and during the outbreak. These effects result in lower cloud bases and stronger low-level wind shear in the warm sector of the extratropical cyclone generating the outbreak, two indicators of higher probability of tornadogenesis and tornado intensity and longevity. These mechanisms may contribute to tornado modulation by aerosols, highlighting the need to consider aerosol feedbacks in numerical severe weather forecasting.

Mars south polar spring and summer behavior observed by TES: seasonal cap evolution controlled by frost grain size

USGS Publications Warehouse

Kieffer, Hugh H.; Titus, Timothy N.; Mullins, Kevin F.; Christensen, Philip R.

2000-01-01

Thermal Emission Spectrometer (TES) observations of the recession phase of Mars' south polar cap are used to quantitatively map this recession in both thermal and visual appearance. Geographically nonuniform behavior interior to the cap is characterized by defining several small regions which exemplify the range of behavior. For most of the cap, while temperatures remain near the CO2 frost point, albedos slowly increase with the seasonal rise of the Sun, then drop rapidly as frost patches disappear over a period of ∼20 days. A “Cryptic” region remains dark and mottled throughout its cold period. TES observations are compared with first-order theoretical spectra of solid CO2 frost with admixtures of dust and H2O. The TES spectra indicate that the Cryptic region has much larger grained solid CO2 than the rest of the cap and that the solid CO2 here may be in the form of a slab. The Mountains of Mitchel remain cold and bright well after other areas at comparable latitude, apparently as a result of unusually small size of the CO2 frost grains; we found little evidence for a significant presence of H2O. Although CO2 grain size may be the major difference between these regions, incorporated dust is also required to match the observations; a self-cleaning process carries away the smaller dust grains. Comparisons with Viking observations indicate little difference in the seasonal cycle 12 Martian years later. The observed radiation balance indicates CO2 sublimation budgets of up to 1250 kg m−2. Regional atmospheric dust is common; localized dust clouds are seen near the edge of the cap prior to the onset of a regional dust storm and interior to the cap during the storm.

Regional scale climatic trends derived from Younger Dryas glaciers in the U.K.

NASA Astrophysics Data System (ADS)

Pearce, D.; Rea, B. R.; Barr, I.; Small, D.; McDougall, D.

2014-12-01

In the U.K., the glacial geomorphological record has been utilised to infer paleo-glacier geometries and ice dynamics, with much of this work focussing on the Scottish Highlands during the Younger Dryas (YD; c. 12.9 - 11.7 ka BP). During the YD the West Highlands Ice-cap covered the majority of the Scottish Highlands (c. 13,000 sq mi), which is thought to have affected accumulation rates beyond the ice-cap margins, resulting in a steep (c. 80%) easterly decline in precipitation and smaller ice-masses. We present multi-proxy data investigating YD glaciation in the Tweedsmuir Hills, Southern Uplands, Scotland (55°46' N, 03°34' W), suggesting conditions were less arid. The area forms the most easterly upland region in the Southern Uplands and south of the West Highlands Ice-cap, reaching an altitude of 840 m and covering c. 200 sq mi. Results of air-photo interpretation and field mapping, which utilised a morphostratigraphic approach, have demonstrated a more extensive glaciation than previously mapped. The reconstruction consists of two separate icefields covering an area c. 40 sq mi. and new 14C dates of basal contact organics place the ice-mass within the context of the YD but new Cosmogenic Nuclide Analysis (CNA) of bedrock and in situ boulders are inconclusive, implying limited erosion and limited resetting during the YD. Equilibrium Line Altitudes are calculated to have ranged from c. 419 - 634 m. Paleo-precipitation values were derived using two precipitation-temperature relationships and suggest slightly lower totals than YD ice-masses located on the west coast of the U.K. but do not support a significant easterly reduction in precipitation. Analysis of present-day (c. 30 year) meteorological data across the U.K. demonstrates a pronounced reduction in precipitation of c. 50% on the east coast. This disparity between present-day and glacier-based YD precipitation patterns is partly attributable to the methodology employed in glacier reconstruction and represents an avenue for future research. These results differ significantly from the traditional paradigm which due to low accumulation rates, only restricted ice-masses developed in the Tweedsmuir Hills. Within a wider context this data questions the steep precipitation gradients thought to have been present during the YD.

ARC-1990-A91-2001

NASA Image and Video Library

1990-02-19

Range : 60,000 miles These images are two versions of a near-infrafed map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft.The map shows the turbulent, cloudy middle atmosphere some 30-33 miles above the surface, 6-10 miles below the visible cloudtops. The image to the left shows the radiant heat from the lower atmosphere (about 400 degrees F) ahining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. This cloud layer is at about 170 degrees F, at a pressure about 1/2 Earth's atmospheric pressure. About 2/3 of the dark hemisphere is visible, centered on longitude 350 West, with bright slsivers of daylit high clouds visible at top and bottom left. The right image, a modified negative, represents what scientists believe would be the visual appearance of this mid-level cloud deck in daylight, with the clouds reflecting sunlight instead of clocking out infrared from the hot planet and lower atmosphere. Near the equator, the clouds appear fluffy and clocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude. The Near Infrared Mapping Spectrometer (NIMS) on the Galileo is a combined mapping (imaging) and spectral instrument. It can sense 408 contiguous wavelengths from 0.7 microns (deep red) to 5.2 microns, and can construct a map or image by mechanical scanning. It can spectroscopic-ally analyze atmospheres and surfaces and construct thermal and chemical maps.

ARC-1990-A91-2002

NASA Image and Video Library

1990-02-10

Range : 60,000 miles These images are two versions of a near-infrafed map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft.The map shows the turbulent, cloudy middle atmosphere some 30-33 miles above the surface, 6-10 miles below the visible cloudtops. The image to the left shows the radiant heat from the lower atmosphere (about 400 degrees F) ahining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. This cloud layer is at about 170 degrees F, at a pressure about 1/2 Earth's atmospheric pressure. About 2/3 of the dark hemisphere is visible, centered on longitude 350 West, with bright slsivers of daylit high clouds visible at top and bottom left. The right image, a modified negative, represents what scientists believe would be the visual appearance of this mid-level cloud deck in daylight, with the clouds reflecting sunlight instead of clocking out infrared from the hot planet and lower atmosphere. Near the equator, the clouds appear fluffy and clocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude. The Near Infrared Mapping Spectrometer (NIMS) on the Galileo is a combined mapping (imaging) and spectral instrument. It can sense 408 contiguous wavelengths from 0.7 microns (deep red) to 5.2 microns, and can construct a map or image by mechanical scanning. It can spectroscopic-ally analyze atmospheres and surfaces and construct thermal and chemical maps.

Landscape evolution on Mars - A model of aeolian denudation in Gale Crater

NASA Astrophysics Data System (ADS)

Day, M. D.; Kocurek, G.; Grotzinger, J. P.

2015-12-01

Aeolian erosion has been the dominant geomorphic agent to shape the surface of Mars for the past ~3.5 billion years. Although individual geomorphic features evidencing aeolian activity are well understood (e.g., yardangs, dune fields, and wind streaks), landscapes formed by aeolian erosion remain poorly characterized. Intra-crater sedimentary mounds are hypothesized to have formed by wind deflation of craters once filled with flat-lying strata, and, therefore, should be surrounded by landscapes formed by aeolian erosion. Here we present a landscape evolution model that provides both an initial characterization of aeolian landscapes, and a mechanism for large-scale excavation. Wind excavation of Gale Crater to form the 5 km high Mount Sharp would require removal of 6.4 x 104 km3 of sediment. Imagery in Gale Crater from satellites and the Mars Science Laboratory rover Curiosity shows a surface characterized by first-cycle aeolian erosion of bedrock. The overall landscape is interpreted to represent stages in a cycle of aeolian deflation and excavation, enhanced by physical weathering (e.g., thermal fracturing, cratering). Initial wind erosion of bedrock is enhanced along fractures, producing retreating scarps. Underlying less resistant layers then erode faster than the armoring cap rock, increasing relief in scarps to form retreating mesas. As scarp retreat continues, boulders from the armoring cap unit break away and cover the hillslopes of less resistant material below the scarps. Eventually all material from the capping unit is eroded away and a boulder-capped hill remains. Winnowing of fine material flattens hillslope topography, leaving behind a desert pavement. Over long enough time, this pavement is breached and the cycle begins anew. This cycle of landscape denudation by the wind is similar to that of water, but lacks characteristic subaqueous features such as dendritic drainage networks.

Clouds, Aerosol, and Precipitation in the Marine Boundary Layer: An ARM Mobile Facility Deployment

NASA Technical Reports Server (NTRS)

Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew;

Intercomparisons of marine boundary layer cloud properties from the ARM CAP-MBL campaign and two MODIS cloud products

NASA Astrophysics Data System (ADS)

Zhang, Zhibo; Dong, Xiquan; Xi, Baike; Song, Hua; Ma, Po-Lun; Ghan, Steven J.; Platnick, Steven; Minnis, Patrick

2017-02-01

From April 2009 to December 2010, the Department of Energy Atmospheric Radiation Measurement (ARM) program carried out an observational field campaign on Graciosa Island, targeting the marine boundary layer (MBL) clouds over the Azores region. In this paper, we present an intercomparison of the MBL cloud properties, namely, cloud liquid water path (LWP), cloud optical thickness (COT), and cloud-droplet effective radius (CER), among retrievals from the ARM mobile facility and two Moderate Resolution Imaging Spectroradiometer (MODIS) cloud products (Goddard Space Flight Center (GSFC)-MODIS and Clouds and Earth's Radiant Energy System-MODIS). A total of 63 daytime single-layer MBL cloud cases are selected for intercomparison. Comparison of collocated retrievals indicates that the two MODIS cloud products agree well on both COT and CER retrievals, with the correlation coefficient R > 0.95, despite their significant difference in spatial sampling. In both MODIS products, the CER retrievals based on the 2.1 µm band (CER2.1) are significantly larger than those based on the 3.7 µm band (CER3.7). The GSFC-MODIS cloud product is collocated and compared with ground-based ARM observations at several temporal-spatial scales. In general, the correlation increases with more precise collocation. For the 63 selected MBL cloud cases, the GSFC-MODIS LWP and COT retrievals agree reasonably well with the ground-based observations with no apparent bias and correlation coefficient R around 0.85 and 0.70, respectively. However, GSFC-MODIS CER3.7 and CER2.1 retrievals have a lower correlation (R 0.5) with the ground-based retrievals. For the 63 selected cases, they are on average larger than ground observations by about 1.5 µm and 3.0 µm, respectively. Taking into account that the MODIS CER retrievals are only sensitive to cloud top reduces the bias only by 0.5 µm.

Southern Half of Spirit's 'Bonestell' Panorama (Anaglyph)

NASA Technical Reports Server (NTRS)

2008-01-01

This stereo, 180-degree panorama shows the southward vista from the location where Spirit is spending its third Martian winter inside Mars' Gusev Crater. The rover's overwintering location is on the northern edge of a low plateau informally called 'Home Plate,' which is about 80 meters or 260 feet in diameter.

The view combines a stereo pair so that it appears three-dimensional when seen through blue-red glasses.

Spirit took the first of the images that are combined into this view during the mission's 1,477th Martian day, or sol, (February 28, 2008) two weeks after the rover made its last move to reach the location where it would stop driving for the winter. Solar energy at Gusev Crater is so limited during the Martian winter that Spirit does not generate enough electricity to drive, nor even enough to take many images per day. The last frame for this mosaic was taken on Sol 1599 (July 2, 2008). The rover team plans for Spirit to finish taking images for the northern half of the scene during the Martian spring.

The northwestern edge of Home Plate is visible in the right foreground. The blockier, more sharply shadowed texture there is layered sandstone whose layering is tilted inward toward the edge of the Home Plate platform. A dark rock on top of Home Plate in that area is a porous volcanic basalt unlike rocks nearby. The northeastern edge of Home Plate is visible in the left foreground. Spirit first climbed onto Home Plate on that region, in early 2006.

Rover tracks from driving by Spirit are visible on Home plate in the center and right of the image. These were made during Spirit's second exploration on top of the plateau, which began when Spirit climbed onto the southern edge of Home Plate in September, 2007.

In the center foreground, the turret of tools at the end of Spirit's robotic arm appears in duplicate because the arm was repositioned between the days when the images making up that part of the mosaic were taken.

On the horizon, the highest point is 'McCool Hill.' This is one of the seven larger hills in the Columbia Hills range. Home Plate is in the inner basin of the range, between McCool Hill to the south and 'Husband Hill' to the north. To the right of McCool Hill, in the center of the image and closer to Home Plate, is a smaller hill capped with a light-toned outcrop. This hill is called 'Von Braun,' and it is a possible destination the rover team has discussed for the next season of driving by Spirit, after the solar energy level increases in the Martian spring. The flat horizon in the right-hand portion of the panorama is the basaltic plain onto which Spirit landed on Jan. 4, 2004.

Atmospheric Collapse on Early Mars: The Role of CO2 Clouds

NASA Technical Reports Server (NTRS)

Kahre, M. A.; Haberle, R. M.; Steakley, K. E.; Murphy, J. R.; Kling, A.

2017-01-01

The abundance of evidence that liquid water flowed on the surface early in Mars' history strongly implies that the early Martian atmosphere was significantly more massive than it is today. While it seems clear that the total CO2 inventory was likely substantially larger in the past, the fundamental question about the physical state of that CO2 is not completely understood. Because the temperature at which CO2 condenses increases with surface pressure, surface CO2 ice is more likely to form and persist as the atmospheric mass increases. For the atmosphere to remain stable against collapse, there must be enough energy, distributed planet wide, to stave off the formation of permanent CO2 caps that leads to atmospheric collapse. The presence of a "faint young sun" that was likely about 25 percent less luminous 3.8 billion years ago than the sun today makes this even more difficult. Several physical processes play a role in the ultimate stability of a CO2 atmosphere. The system is regulated by the energy balance between solar insolation, the radiative effects of the atmosphere and its constituents, atmospheric heat transport, heat exchange between the surface and the atmosphere, and latent heating/cooling. Specific considerations in this balance for a given orbital obliquity/eccentricity and atmospheric mass are the albedo of the caps, the dust content of the atmosphere, and the presence of water and/or CO2 clouds. Forget et al. show that, for Mars' current obliquity (in a circular orbit), CO2 atmospheres ranging in surface pressure from 500 hectopascals to 3000 hectopascals would have been stable against collapsing into permanent surface ice reservoirs. Soto et al. examined a similar range in initial surface pressure to investigate atmospheric collapse and to compute collapse rates. CO2 clouds and their radiative effects were included in Forget et al. but they were not included in Soto et al. Here we focus on how CO2 clouds affect the stability of the atmosphere against collapse.

ARC-1990-AC91-2005

NASA Image and Video Library

1990-02-10

Range : 60,000 miles This image is a false-color version of a near- infrared map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard Galileo. Taken at an infrared wavelength of 2.3 microns (about three times the longest wavelength visible to the human eye) the map shows the turbulent, cloudy middle atmosphere some 30-33 miles above the surface, 6-10 miles below the visible cloudtops. The image shows the radiant heat from the lower atmosphere (about 400 degrees F) shining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. The colors indicate relative cloud transparency; white and red show thin cloud regions, while black and blue represent relatively this clouds. This cloud layer is at about 170 degrees F., at a pressure about 1/2 Earth's atmospheric pressure. About 2/3 of the dark hemisphere is visible, centered on longitude 350 West, with bright slivers of daylit high clouds visible at top and bottom left. Near the equator, the clouds appear fluffy and blocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude. The Near Infrared Mapping Spectrometer (NIMS) on the Galileo is a combined mapping (imaging) and spectral instrument. It can sense 408 contiguous wavelengths from 0.7 microns (deep red) to 5.2 microns, and can construct a map or image by mechanical scanning. It can spectroscopic-ally analyze atmospheres and surfaces and construct thermal and chemical maps. Designed and operated by scientists and engineers at the JPL, NIMS involves 15 scientists in the US, England and France.

Intercomparisons of Marine Boundary Layer Cloud Properties from the ARM CAP-MBL Campaign and Two MODIS Cloud Products

NASA Technical Reports Server (NTRS)

Zhang, Zhibo; Dong, Xiquan; Xi, Baike; Song, Hua; Ma, Po-Lun; Ghan, Steven J.; Platnick, Steven; Minnis, Patrick

2017-01-01

From April 2009 to December 2010, the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program carried out an observational field campaign on Graciosa Island, targeting the marine boundary layer (MBL) clouds over the Azores region. In this paper, we present an inter-comparison of the MBL cloud properties, namely, cloud liquid water path (LWP), cloud optical thickness (COT) and cloud-droplet effective radius (CER), among retrievals from the ARM mobile facility (AMF) and two Moderate Resolution Spectroradiometer (MODIS) cloud products (GSFC-MODIS and CERES-MODIS). A total of 63 daytime single-layer MBL cloud cases are selected for inter-comparison. Comparison of collocated retrievals indicates that the two MODIS cloud products agree well on both COT and CER retrievals, with the correlation coefficient R greater than 0.95 despite their significant difference in spatial sampling. In both MODIS products, the CER retrievals based on the 2.1 micrometers band (CER(sub 2.1)) is significantly smaller than that based on the 3.7 micrometers band (CER(sub 3.7)). The GSFC-MODIS cloud product is collocated and compared with ground-based ARM observations at several temporal spatial scales. In general, the correlation increases with more precise collocation. For the 63 selected MBL cloud cases, the GSFC-MODIS LWP and COT retrievals agree reasonably well with the ground-based observations with no apparent bias and correlation coefficient R around 0.85 and 0.70, respectively. However, GSFC-MODIS CER(sub 3.7) and CER(sub 2.1) retrievals have a lower correlation (R is approximately 0.5) with the ground-based retrievals. For the 63 selected cases, they are on average larger than ground observations by about 1.5 micrometers and 3.0 micrometers, respectively. Taking into account that the MODIS CER retrievals are only sensitive to cloud top reduces the bias only by 0.5 micrometers.

Early views of the martian surface from the Mars Orbiter Camera of Mars Global Surveyor.

PubMed

Malin, M C; Carr, M H; Danielson, G E; Davies, M E; Hartmann, W K; Ingersoll, A P; James, P B; Masursky, H; McEwen, A S; Soderblom, L A; Thomas, P; Veverka, J; Caplinger, M A; Ravine, M A; Soulanille, T A; Warren, J L

1998-03-13

High-resolution images of the martian surface at scales of a few meters show ubiquitous erosional and depositional eolian landforms. Dunes, sandsheets, and drifts are prevalent and exhibit a range of morphology, composition (inferred from albedo), and age (as seen in occurrences of different dune orientations at the same location). Steep walls of topographic depressions such as canyons, valleys, and impact craters show the martian crust to be stratified at scales of a few tens of meters. The south polar layered terrain and superposed permanent ice cap display diverse surface textures that may reflect the complex interplay of volatile and non-volatile components. Low resolution regional views of the planet provide synoptic observations of polar cap retreat, condensate clouds, and the lifecycle of local and regional dust storms.

The Boeing Delta II rocket with Mars Polar Lander aboard lifts off at Pad 17B, CCAS

NASA Technical Reports Server (NTRS)

1999-01-01

Amid clouds of exhaust and into a gray-clouded sky , a Boeing Delta II expendable launch vehicle lifts off with NASA's Mars Polar Lander at 3:21:10 p.m. EST from Launch Complex 17B, Cape Canaveral Air Station. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern- most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

CGILS Phase 2 LES intercomparison of response of subtropical marine low cloud regimes to CO 2 quadrupling and a CMIP3 composite forcing change: Large eddy simulation of cloud feedbacks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blossey, Peter N.; Bretherton, Christopher S.; Cheng, Anning

We extended Phase 1 of the CGILS large-eddy simulation (LES) intercomparison in order to understand if subtropical marine boundary-layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO 2 near-equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well-mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. Our results are generally consistent with a single-LES studymore » of Bretherton et al. (2013) on which this intercomparison was based. Both quadrupled CO 2 and the composite climate perturbation result in less cloud and a shallower boundary layer for all models in well-mixed stratocumulus and for all but a single LES in decoupled stratocumulus and shallow cumulus, corroborating similar findings from global climate models (GCMs). For both perturbations, the amount of cloud reduction varies across the models, but there is less intermodel scatter than in GCMs. Furthermore, the cloud radiative effect changes are much larger in the stratocumulus-capped regimes than in the shallow cumulus regime, for which precipitation buffering may damp the cloud response. In the decoupled stratocumulus and cumulus regimes, both the CO 2 increase and CMIP3 perturbations reduce boundary-layer decoupling, due to the shallowing of inversion height.« less

CGILS Phase 2 LES intercomparison of response of subtropical marine low cloud regimes to CO 2 quadrupling and a CMIP3 composite forcing change: Large eddy simulation of cloud feedbacks

DOE PAGES

Blossey, Peter N.; Bretherton, Christopher S.; Cheng, Anning; ...

2016-10-27

We extended Phase 1 of the CGILS large-eddy simulation (LES) intercomparison in order to understand if subtropical marine boundary-layer clouds respond to idealized climate perturbations consistently in six LES models. Here the responses to quadrupled carbon dioxide (“fast adjustment”) and to a composite climate perturbation representative of CMIP3 multimodel mean 2×CO 2 near-equilibrium conditions are analyzed. As in Phase 1, the LES is run to equilibrium using specified steady summertime forcings representative of three locations in the Northeast Pacific Ocean in shallow well-mixed stratocumulus, decoupled stratocumulus, and shallow cumulus cloud regimes. Our results are generally consistent with a single-LES studymore » of Bretherton et al. (2013) on which this intercomparison was based. Both quadrupled CO 2 and the composite climate perturbation result in less cloud and a shallower boundary layer for all models in well-mixed stratocumulus and for all but a single LES in decoupled stratocumulus and shallow cumulus, corroborating similar findings from global climate models (GCMs). For both perturbations, the amount of cloud reduction varies across the models, but there is less intermodel scatter than in GCMs. Furthermore, the cloud radiative effect changes are much larger in the stratocumulus-capped regimes than in the shallow cumulus regime, for which precipitation buffering may damp the cloud response. In the decoupled stratocumulus and cumulus regimes, both the CO 2 increase and CMIP3 perturbations reduce boundary-layer decoupling, due to the shallowing of inversion height.« less

Assessment of biomass burning smoke influence on environmental conditions for multi-year tornado outbreaks by combining aerosol-aware microphysics and fire emission constraints.

PubMed

Saide, Pablo E; Thompson, Gregory; Eidhammer, Trude; da Silva, Arlindo M; Pierce, R Bradley; Carmichael, Gregory R

2016-09-16

We use the WRF system to study the impacts of biomass burning smoke from Central America on several tornado outbreaks occurring in the US during spring. The model is configured with an aerosol-aware microphysics parameterization capable of resolving aerosol-cloud-radiation interactions in a cost-efficient way for numerical weather prediction (NWP) applications. Primary aerosol emissions are included and smoke emissions are constrained using an inverse modeling technique and satellite-based AOD observations. Simulations turning on and off fire emissions reveal smoke presence in all tornado outbreaks being studied and show an increase in aerosol number concentrations due to smoke. However, the likelihood of occurrence and intensification of tornadoes is higher due to smoke only in cases where cloud droplet number concentration in low level clouds increases considerably in a way that modifies the environmental conditions where the tornadoes are formed (shallower cloud bases and higher low-level wind shear). Smoke absorption and vertical extent also play a role, with smoke absorption at cloud-level tending to burn-off clouds and smoke absorption above clouds resulting in an increased capping inversion. Comparing these and WRF-Chem simulations configured with a more complex representation of aerosol size and composition and different optical properties, microphysics and activation schemes, we find similarities in terms of the simulated aerosol optical depths and aerosol impacts on near-storm environments. This provides reliability on the aerosol-aware microphysics scheme as a less computationally expensive alternative to WRF-Chem for its use in applications such as NWP and cloud-resolving simulations.

Assessment of Biomass Burning Smoke Influence on Environmental Conditions for Multi-Year Tornado Outbreaks by Combining Aerosol-Aware Microphysics and Fire Emission Constraints

NASA Technical Reports Server (NTRS)

Saide, Pablo E.; Thompson, Gregory; Eidhammer, Trude; Da Silva, Arlindo M.; Pierce, R. Bradley; Carmichael, Gregory R.

2016-01-01

We use the WRF system to study the impacts of biomass burning smoke from Central America on several tornado outbreaks occurring in the US during spring. The model is configured with an aerosol-aware microphysics parameterization capable of resolving aerosol-cloud-radiation interactions in a cost-efficient way for numerical weather prediction (NWP) applications. Primary aerosol emissions are included and smoke emissions are constrained using an inverse modeling technique and satellite-based AOD observations. Simulations turning on and off fire emissions reveal smoke presence in all tornado outbreaks being studied and show an increase in aerosol number concentrations due to smoke. However, the likelihood of occurrence and intensification of tornadoes is higher due to smoke only in cases where cloud droplet number concentration in low level clouds increases considerably in a way that modifies the environmental conditions where the tornadoes are formed (shallower cloud bases and higher low-level wind shear). Smoke absorption and vertical extent also play a role, with smoke absorption at cloud-level tending to burn-off clouds and smoke absorption above clouds resulting in an increased capping inversion. Comparing these and WRF-Chem simulations configured with a more complex representation of aerosol size and composition and different optical properties, microphysics and activation schemes, we find similarities in terms of the simulated aerosol optical depths and aerosol impacts on near-storm environments. This provides reliability on the aerosol-aware microphysics scheme as a less computationally expensive alternative to WRFChem for its use in applications such as NWP and cloud-resolving simulations.

Single-Column Model Simulations of Subtropical Marine Boundary-Layer Cloud Transitions Under Weakening Inversions

NASA Astrophysics Data System (ADS)

Neggers, R. A. J.; Ackerman, A. S.; Angevine, W. M.; Bazile, E.; Beau, I.; Blossey, P. N.; Boutle, I. A.; de Bruijn, C.; Cheng, A.; van der Dussen, J.; Fletcher, J.; Dal Gesso, S.; Jam, A.; Kawai, H.; Cheedela, S. K.; Larson, V. E.; Lefebvre, M.-P.; Lock, A. P.; Meyer, N. R.; de Roode, S. R.; de Rooy, W.; Sandu, I.; Xiao, H.; Xu, K.-M.

2017-10-01

Results are presented of the GASS/EUCLIPSE single-column model intercomparison study on the subtropical marine low-level cloud transition. A central goal is to establish the performance of state-of-the-art boundary-layer schemes for weather and climate models for this cloud regime, using large-eddy simulations of the same scenes as a reference. A novelty is that the comparison covers four different cases instead of one, in order to broaden the covered parameter space. Three cases are situated in the North-Eastern Pacific, while one reflects conditions in the North-Eastern Atlantic. A set of variables is considered that reflects key aspects of the transition process, making use of simple metrics to establish the model performance. Using this method, some longstanding problems in low-level cloud representation are identified. Considerable spread exists among models concerning the cloud amount, its vertical structure, and the associated impact on radiative transfer. The sign and amplitude of these biases differ somewhat per case, depending on how far the transition has progressed. After cloud breakup the ensemble median exhibits the well-known "too few too bright" problem. The boundary-layer deepening rate and its state of decoupling are both underestimated, while the representation of the thin capping cloud layer appears complicated by a lack of vertical resolution. Encouragingly, some models are successful in representing the full set of variables, in particular, the vertical structure and diurnal cycle of the cloud layer in transition. An intriguing result is that the median of the model ensemble performs best, inspiring a new approach in subgrid parameterization.

Effects of Cloud-Microphysics on Tropical Atmospheric Hydrologic Processes in the GEOS GCM

NASA Technical Reports Server (NTRS)

Lau, K. M.; Wu, H. T.; Sud, Y. C.; Walker, G. K.

2004-01-01

The sensitivity of tropical atmospheric hydrologic processes to cloud-microphysics is investigated using the NASA GEOS GCM. Results show that a faster autoconversion - rate produces more warm rain and less clouds at all levels. Fewer clouds enhances longwave cooling and reduces shortwave heating in the upper troposphere, while more warm rain produces increased condensation heating in the lower troposphere. This vertical heating differential destablizes the tropical atmosphere, producing a positive feedback resulting in more rain over the tropics. The feedback is maintained via a two-cell secondary circulation. The lower cell is capped by horizontal divergence and maximum cloud detrainment near the melting/freezing, with rising motion in the warm rain region connected to descending motion in the cold rain region. The upper cell is found above the freezing/melting level, with longwave-induced subsidence in the warm rain and dry regions, coupled to forced ascent in the deep convection region. The tropical large scale circulation is found to be very sensitive to the radiative-dynamic effects induced by changes in autoconversion rate. Reduced cloud-radiation processes feedback due to a faster autoconversion rate results in intermittent but more energetic eastward propagating Madden and Julian Oscillations (MJO). Conversely,-a slower autconversion rate, with increased cloud radiation produces MJO's with more realistic westward propagating transients, resembling a supercloud cluster structure. Results suggests that warm rain and associated low and mid level clouds, i.e., cumulus congestus, may play a critical role in regulating the time-intervals of deep convections and hence the fundamental time scales of the MJO.

Deep convective clouds at the tropopause

NASA Astrophysics Data System (ADS)

Aumann, H. H.; Desouza-Machado, S. G.

2010-07-01

Data from the Advanced Infrared Sounder (AIRS) on the EOS Aqua spacecraft identify thousands of cloud tops colder than 225 K, loosely referred to as Deep Convective Clouds (DCC). Many of these cloud tops have "inverted" spectra, i.e. areas of strong water vapor, CO2 and ozone opacity, normally seen in absorption, are now seen in emission. We refer to these inverted spectra as DCCi. They are found in about 0.4% of all spectra from the tropical oceans excluding the Western Tropical Pacific (WTP), 1.1% in the WTP. The cold clouds are the anvils capping thunderstorms and consist of optically thick cirrus ice clouds. The precipitation rate associated with DCCi suggests that imbedded in these clouds, protruding above them, and not spatially resolved by the AIRS 15 km FOV, are even colder bubbles, where strong convection pushes clouds to within 5 hPa of the pressure level of the tropopause cold point. Associated with DCCi is a local upward displacement of the tropopause, a cold "bulge", which can be seen directly in the brightness temperatures of AIRS and AMSU channels with weighting function peaking between 40 and 2 hPa, without the need for a formal temperature retrieval. The bulge is not resolved by the analysis in numerical weather prediction models. The locally cold cloud tops relative to the analysis give the appearance (in the sense of an "illusion") of clouds overshooting the tropopause and penetrating into the stratosphere. Based on a simple model of optically thick cirrus clouds, the spectral inversions seen in the AIRS data do not require these clouds to penetrate into the stratosphere. However, the contents of the cold bulge may be left in the lower stratosphere as soon as the strong convection subsides. The heavy precipitation and the distortion of the temperature structure near the tropopause indicate that DCCi are associated with intense storms. Significant long-term trends in the statistical properties of DCCi could be interesting indicators of climate change.

Liquid water content variation with altitude in clouds over Europe

NASA Astrophysics Data System (ADS)

Andreea, Boscornea; Sabina, Stefan

2013-04-01

Cloud water content is one of the most fundamental measurements in cloud physics. Knowledge of the vertical variability of cloud microphysical characteristics is important for a variety of reasons. The profile of liquid water content (LWC) partially governs the radiative transfer for cloudy atmospheres, LWC profiles improves our understanding of processes acting to form and maintain cloud systems and may lead to improvements in the representation of clouds in numerical models. Presently, in situ airborne measurements provide the most accurate information about cloud microphysical characteristics. This information can be used for verification of both numerical models and cloud remote sensing techniques. The aim of this paper was to analyze the liquid water content (LWC) measurements in clouds, in time of the aircraft flights. The aircraft and its platform ATMOSLAB - Airborne Laboratory for Environmental Atmospheric Research is property of the National Institute for Aerospace Research "Elie Carafoli" (INCAS), Bucharest, Romania. The airborne laboratory equipped for special research missions is based on a Hawker Beechcraft - King Air C90 GTx aircraft and is equipped with a sensors system CAPS - Cloud, Aerosol and Precipitation Spectrometer (30 bins, 0.51-50 m). The processed and analyzed measurements are acquired during 4 flights from Romania (Bucharest, 44°25'57″N 26°06'14″E) to Germany (Berlin 52°30'2″N 13°23'56″E) above the same region of Europe. The flight path was starting from Bucharest to the western part of Romania above Hungary, Austria at a cruse altitude between 6000-8500 m, and after 5 hours reaching Berlin. In total we acquired data during approximately 20 flight hours and we presented the vertical and horizontal LWC variations for different cloud types. The LWC values are similar for each type of cloud to values from literature. The vertical LWC profiles in the atmosphere measured during takeoff and landing of the aircraft have shown their dependence of the meteorological parameters.

Single-Column Model Simulations of Subtropical Marine Boundary-Layer Cloud Transitions Under Weakening Inversions: SCM SIMULATIONS OF CLOUD TRANSITIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neggers, R. A. J.; Ackerman, A. S.; Angevine, W. M.

Results are presented of the GASS/EUCLIPSE single-column model inter-comparison study on the subtropical marine low-level cloud transition. A central goal is to establish the performance of state-of-the-art boundary-layer schemes for weather and climate mod- els for this cloud regime, using large-eddy simulations of the same scenes as a reference. A novelty is that the comparison covers four different cases instead of one, in order to broaden the covered parameter space. Three cases are situated in the North-Eastern Pa- cific, while one reflects conditions in the North-Eastern Atlantic. A set of variables is considered that reflects key aspects of the transitionmore » process, making use of simple met- rics to establish the model performance. Using this method some longstanding problems in low level cloud representation are identified. Considerable spread exists among models concerning the cloud amount, its vertical structure and the associated impact on radia- tive transfer. The sign and amplitude of these biases differ somewhat per case, depending on how far the transition has progressed. After cloud breakup the ensemble median ex- hibits the well-known “too few too bright” problem. The boundary layer deepening rate and its state of decoupling are both underestimated, while the representation of the thin capping cloud layer appears complicated by a lack of vertical resolution. Encouragingly, some models are successful in representing the full set of variables, in particular the verti- cal structure and diurnal cycle of the cloud layer in transition. An intriguing result is that the median of the model ensemble performs best, inspiring a new approach in subgrid pa- rameterization.« less

Further Research on the Electrification of Pyrocumulus Clouds

NASA Technical Reports Server (NTRS)

Lang, Timothy J.; Laroche, Kendell; Baum, Bryan; Bateman, Monte; Mach, Douglas

2015-01-01

Past research on pyrocumulus electrification has demonstrated that a variety of lightning types can occur, including cloud-to-ground (CG) flashes, sometimes of dominant positive polarity, as well as small intra-cloud (IC) discharges in the upper levels of the pyro-cloud. In Colorado during summer 2012, the first combined polarimetric radar, multi-Doppler radar, and three-dimensional lightning mapping array (LMA) observations of lightning-producing pyrocumulus were obtained. These observations suggested that the National Lightning Detection Network (NLDN) was not sensitive enough to detect the small IC flashes that appear to be the dominant mode of lightning in these clouds. However, after an upgrade to the network in late 2012, the NLDN began detecting some of this pyrocumulus lightning. Multiple pyrocumulus clouds documented by the University of Wisconsin for various fires in 2013 and 2014 (including over the Rim, West Fork Complex, Yarnell Hill, Hardluck, and several other incidents) are examined and reported on here. This study exploits the increased-sensitivity NLDN as well as the new nationwide U.S. network of polarimetric Next-generation Radars (NEXRADs). These observations document the common occurrence of a polarimetric "dirty ice" signature - modest reflectivities (20-40+ dBZ), near-zero differential reflectivity, and reduced correlation coefficient (less than 0.9) - prior to the production of lightning. This signature is indicative of a mixture of ash and ice particles in the upper levels of the pyro-cloud (less than -20 C), with the ice interpreted as being necessary for pyro-cloud electrification. Pseudo-Geostationary Lightning Mapper (GLM) data will be produced from the 2012 LMA observations, and the ability of GLM to detect small pyrocumulus ICs will be assessed. The utility of lightning and polarimetric radar for documenting rapid wildfire growth, as well as for documenting pyrocumulus impacts on the composition of the upper troposphere/lower stratosphere (UTLS), will be discussed.

The magnetospheric and ionospheric response to a very strong interplanetary shock and coronal mass ejection

NASA Astrophysics Data System (ADS)

Ridley, A. J.; De Zeeuw, D. L.; Manchester, W. B.; Hansen, K. C.

2006-01-01

We present results from a coupled magnetospheric and ionospheric simulation of a very strong solar wind shock and coronal mass ejection (CME). The solar wind drivers that are used for this simulation were output from the Sun-to-Earth MHD simulation of the Carrington-like CME reported in Manchester et al. [Manchester IV, W., Ridley, A., Gombosi, T., De Zeeuw, D. Modeling the Sun-Earth propagation of a very fast cme. Adv. Space Res. 38 (this issue), 2006]. We use the University of Michigan's BATS-R-US MHD code to model the global magnetosphere and coupled height integrated ionosphere. As the interplanetary shock swept over the magnetosphere, a wave is observed to propagate through the system. This is evident both in the magnetosphere and ionosphere. On the dayside, the magnetospheric bowshock is shown to bifurcate. The inner shock is pushed close to the inner boundary, where it "bounces" and propagates back outwards to meet the outer bowshock, which is propagating inwards. The inward and outward motion of the bowshocks can be observed propagating down the flanks of the magnetosphere. In the ionosphere, the wave is manifested as two pairs of field-aligned currents moving antisunward. The first pair is opposite of the normal region-1 current system, while the second pair is in the same sense as the normal region-1 system. The ionospheric potential shows a behavior consistent with the field-aligned current pattern, given the strong gradient in the conductance from the dayside to the nightside. As the magnetic cloud flows over the system, the entire magnetopause boundary is observed to move inside of geosynchronous orbit (6.6 Re). At the time of the most extreme solar wind conditions, the magnetopause boundary encounters the inner edge of the magnetospheric simulation domain. During the magnetic cloud, the ionospheric cross-polar cap potential is shown to match the Siscoe et al. [Siscoe, G.L., Erickson, G., Sonnerup, B., Maynard, N., Schoendorf, J., Siebert, K., Weimer, D., White, W., Wilson, G. Hill model of transpolar potential saturation: comparisons with MHD simulations. J. Geophys. Res. 107, 1321, doi:10.1029/2001JA009176, 2002] formulation relating the ionospheric potential to the solar wind and IMF conditions. It is shown that by using this formulation, the extremely large potentials observed in the MHD results are most likely saturated.

Application and Limitations of GPS Radio Occultation (GPS-RO) Data for Atmospheric Boundary Layer Height Detection over the Arctic.

NASA Astrophysics Data System (ADS)

Ganeshan, M.; Wu, D. L.

2014-12-01

Due to recent changes in the Arctic environment, it is important to monitor the atmospheric boundary layer (ABL) properties over the Arctic Ocean, especially to explore the variability in ABL clouds (such as sensitivity and feedback to sea ice loss). For example, radiosonde and satellite observations of the Arctic ABL height (and low-cloud cover) have recently suggested a positive response to sea ice loss during October that may not occur during the melt season (June-September). Owing to its high vertical and spatiotemporal resolution, an independent ABL height detection algorithm using GPS Radio Occultation (GPS-RO) refractivity in the Arctic is explored. Similar GPS-RO algorithms developed previously typically define the level of the most negative moisture gradient as the ABL height. This definition is favorable for subtropical oceans where a stratocumulus-topped ABL is often capped by a layer of sharp moisture lapse rate (coincident with the temperature inversion). The Arctic Ocean is also characterized by stratocumulus cloud cover, however, the specific humidity does not frequently decrease in the ABL capping inversion. The use of GPS-RO refractivity for ABL height retrieval therefore becomes more complex. During winter months (December-February), when the total precipitable water in the troposphere is a minimum, a fairly straightforward algorithm for ABL height retrieval is developed. The applicability and limitations of this method for other seasons (Spring, Summer, Fall) is determined. The seasonal, interannual and spatial variability in the GPS-derived ABL height over the Arctic Ocean, as well as its relation to the underlying surface (ice vs. water), is investigated. The GPS-RO profiles are also explored for the evidence of low-level moisture transport in the cold Arctic environment.

Faint Luminescent Ring over Saturn’s Polar Hexagon

NASA Astrophysics Data System (ADS)

Adriani, Alberto; Moriconi, Maria Luisa; D'Aversa, Emiliano; Oliva, Fabrizio; Filacchione, Gianrico

2015-07-01

Springtime insolation is presently advancing across Saturn's north polar region. Early solar radiation scattered through the gaseous giant's atmosphere gives a unique opportunity to sound the atmospheric structure at its upper troposphere/lower stratosphere at high latitudes. Here, we report the detection of a tenuous bright structure in Saturn's northern polar cap corresponding to the hexagon equatorward boundary, observed by Cassini Visual and Infrared Mapping Spectrometer on 2013 June. The structure is spectrally characterized by an anomalously enhanced intensity in the 3610-3730 nm wavelength range and near 2500 nm, pertaining to relatively low opacity windows between strong methane absorption bands. Our first results suggest that a strong forward scattering by tropospheric clouds, higher in respect to the surrounding cloud deck, can be responsible for the enhanced intensity of the feature. This can be consistent with the atmospheric dynamics associated with the jet stream embedded in the polar hexagon. Further investigations at higher spectral resolution are needed to better assess the vertical distribution and microphysics of the clouds in this interesting region.

A Summary of the Naval Postgraduate School Research Program

DTIC Science & Technology

1988-08-30

Teh.(accepted). F. P. Kel lyr C.-F. Shih , D. L. Reinke, and T. H. Vonder Haart "Metric Statistical Comparison of Objective Cloud Detectors," Er...February 5, 1988, Anaheim, CAP American Meteorological Society# Boston, MA. 211 Publications: C.-F. Shih , M. Wentzel, and T. H. Yonder Haar, (cont... Shih , "Estimation of Meteorological Parameters Over Mesoscale Regions from Satel l ite and In Situ Data." Preprints, Third Conference DR Satellite

Falcon Reservoir, Brownsville, TX, USA

NASA Image and Video Library

1991-08-11

STS043-151-043 (8 August 1991) --- The Rio Grande extends across the center of this photograph from Falcon Reservoir to its bulging delta, joining the Gulf of Mexico. Sediment brought down by the river is spread northward and southward by alongshore currents to form the barrier chain of Padre Island and its protected Laguna Madre Speckled agricultural land use patterns in the river valley contrast with range land northward from the white cloud, and with closed canopy forest on hills in Mexico. A Linhof camera with a 90mm lens, was used to expose the frame at 14:43 GMT, Aug. 8, 1991.

Weather features associated with aircraft icing conditions: a case study.

PubMed

Fernández-González, Sergio; Sánchez, José Luis; Gascón, Estíbaliz; López, Laura; García-Ortega, Eduardo; Merino, Andrés

2014-01-01

In the context of aviation weather hazards, the study of aircraft icing is very important because of several accidents attributed to it over recent decades. On February 1, 2012, an unusual meteorological situation caused severe icing of a C-212-200, an aircraft used during winter 2011-2012 to study winter cloud systems in the Guadarrama Mountains of the central Iberian Peninsula. Observations in this case were from a MP-3000A microwave radiometric profiler, which acquired atmospheric temperature and humidity profiles continuously every 2.5 minutes. A Cloud Aerosol and Precipitation Spectrometer (CAPS) was also used to study cloud hydrometeors. Finally, ice nuclei concentration was measured in an isothermal cloud chamber, with the goal of calculating concentrations in the study area. Synoptic and mesoscale meteorological conditions were analysed using the Weather Research and Forecasting (WRF) model. It was demonstrated that topography influenced generation of a mesolow and gravity waves on the lee side of the orographic barrier, in the region where the aircraft experienced icing. Other factors such as moisture, wind direction, temperature, atmospheric stability, and wind shear were decisive in the appearance of icing. This study indicates that icing conditions may arise locally, even when the synoptic situation does not indicate any risk.

The interaction of a magnetic cloud with the Earth - Ionospheric convection in the Northern and Southern Hemispheres for a wide range of quasi-steady interplanetary magnetic field conditions

NASA Technical Reports Server (NTRS)

Freeman, M. P.; Farrugia, C. J.; Burlaga, L. F.; Hairston, M. R.; Greenspan, M. E.; Ruohoniemi, J. M.; Lepping, R. P.

1993-01-01

Observations are presented of the ionospheric convection in cross sections of the polar cap and auroral zone as part of the study of the interaction of the Earth's magnetosphere with the magnetic cloud of January 13-15, 1988. For strongly northward IMF, the convection in the Southern Hemisphere is characterized by a two-cell convection pattern comfined to high latitudes with sunward flow over the pole. The strength of the flows is comparable to that later seen under southward IMF. Superimposed on this convection pattern there are clear dawn-dusk asymmetries associated with a one-cell convection component whose sense depends on the polarity of the magnetic cloud's large east-west magnetic field component. When the cloud's magnetic field turns southward, the convection is characterized by a two-cell pattern extending to lower latitude with antisunward flow over the pole. There is no evident interhemispheric difference in the structure and strength of the convection. Superimposed dawn-dusk asymmetries in the flow patterns are observed which are only in part attributable to the east-west component of the magnetic field.

Soufriere Hills, Montserrat, West Indies

NASA Technical Reports Server (NTRS)

2002-01-01

Volcanic activity on the West Indian island of Montserrat has remained high for several years-the current activity started in 1995. However, remote sensing of the island has been difficult because of frequent cloud cover. The International Space Station crew flew north of the island on a clear day in early July (July 9, 2001) and recorded a vigorous steam plume emanating from the summit of Soufriere Hills. The image also reveals the extensive volcanic mud flows (lahars) and new deltas built out from the coast from the large amounts of volcanic debris delivered downstream by the rivers draining the mountain. As a small island (only 13 x 8 km), all of Montserrat has been impacted by the eruptions. Sources of Information: Smithsonian Global Volcanism Program Italy's Volcanoes Montserrat Volcano Observatory Digital photograph number ISS002-E-9309 was taken on 9 July 2001 from Space Station Alpha and was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

Southern Half of Spirit's 'Bonestell' Panorama (False Color)

NASA Technical Reports Server (NTRS)

2008-01-01

This 180-degree panorama shows the southward vista from the location where Spirit is spending its third Martian winter inside Mars' Gusev Crater. The rover's overwintering location is on the northern edge of a low plateau informally called 'Home Plate,' which is about 80 meters or 260 feet in diameter.

This view combines 168 different exposures taken with Spirit's panoramic Camera (Pancam) 42 pointings with 4 filters at each pointing. Spirit took the first of these frames during the mission's 1,477th Martian day, or sol, (February 28, 2008) two weeks after the rover made its last move to reach the location where it would stop driving for the winter. Solar energy at Gusev Crater is so limited during the Martian winter that Spirit does not generate enough electricity to drive, nor even enough to take many images per day. The last frame for this mosaic was taken on Sol 1599 (July 2, 2008). The rover team plans for Spirit to finish taking images for the northern half of the scene during the Martian spring.

The northwestern edge of Home Plate is visible in the right foreground. The blockier, more sharply shadowed texture there is layered sandstone whose layering is tilted inward toward the edge of the Home Plate platform. A dark rock on top of Home Plate in that area is a porous volcanic basalt unlike rocks nearby. The northeastern edge of Home Plate is visible in the left foreground. Spirit first climbed onto Home Plate on that region, in early 2006.

Rover tracks from driving by Spirit are visible on Home plate in the center and right of the image. These were made during Spirit's second exploration on top of the plateau, which began when Spirit climbed onto the southern edge of Home Plate in September, 2007.

In the center foreground, the turret of tools at the end of Spirit's robotic arm appears in duplicate because the arm was repositioned between the days when the images making up that part of the mosaic were taken.

On the horizon, the highest point is 'McCool Hill.' This is one of the seven larger hills in the Columbia Hills range. Home Plate is in the inner basin of the range, between McCool Hill to the south and 'Husband Hill' to the north. To the right of McCool Hill, in the center of the image and closer to Home Plate, is a smaller hill capped with a light-toned outcrop. This hill is called 'Von Braun,' and it is a possible destination the rover team has discussed for the next season of driving by Spirit, after the solar energy level increases in the Martian spring. The flat horizon in the right-hand portion of the panorama is the basaltic plain onto which Spirit landed on Jan. 4, 2004.

This is a false-color, red-green-blue composite panorama generated from images taken through the Pancam's 750-nanometer, 530-nanometer and 430-nanometer filters. The false color enhances visibility of differences among the types of rock and soil material in the image.

Atmospheric correction for satellite-based volcanic ash mapping and retrievals using ``split window'' IR data from GOES and AVHRR

NASA Astrophysics Data System (ADS)

Yu, Tianxu; Rose, William I.; Prata, A. J.

2002-08-01

Volcanic ash in volcanic clouds can be mapped in two dimensions using two-band thermal infrared data available from meteorological satellites. Wen and Rose [1994] developed an algorithm that allows retrieval of the effective particle size, the optical depth of the volcanic cloud, and the mass of fine ash in the cloud. Both the mapping and the retrieval scheme are less accurate in the humid tropical atmosphere. In this study we devised and tested a scheme for atmospheric correction of volcanic ash mapping and retrievals. The scheme utilizes infrared (IR) brightness temperature (BT) information in two infrared channels (both between 10 and 12.5 μm) and the brightness temperature differences (BTD) to estimate the amount of BTD shift caused by lower tropospheric water vapor. It is supported by the moderate resolution transmission (MODTRAN) analysis. The discrimination of volcanic clouds in the new scheme also uses both BT and BTD data but corrects for the effects of the water vapor. The new scheme is demonstrated and compared with the old scheme using two well-documented examples: (1) the 18 August 1992 volcanic cloud of Crater Peak, Mount Spurr, Alaska, and (2) the 26 December 1997 volcanic cloud from Soufriere Hills, Montserrat. The Spurr example represents a relatively ``dry'' subarctic atmospheric condition. The new scheme sees a volcanic cloud that is about 50% larger than the old. The mean optical depth and effective radii of cloud particles are lower by 22% and 9%, and the fine ash mass in the cloud is 14% higher. The Montserrat cloud is much smaller than Spurr and is more sensitive to atmospheric moisture. It also was located in a moist tropical atmosphere. For the Montserrat example the new scheme shows larger differences, with the area of the volcanic cloud being about 5.5 times larger, the optical depth and effective radii of particles lower by 56% and 28%, and the total fine particle mass in the cloud increased by 53%. The new scheme can be automated and can contribute to more accurate remote volcanic ash detection. More tests are needed to find the best way to estimate the water vapor effects in real time.

Jupiter's High-Altitude Clouds

NASA Technical Reports Server (NTRS)

2007-01-01

The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of Jupiter in this image has a mottled appearance, and the scene is not as dynamic as the equatorial and south polar regions.

The intricate structures revealed in this image are exciting, but they are only part of the story. The New Horizons instruments have taken images of Jupiter at approximately 260 different wavelengths, providing essentially a three-dimensional view of Jupiter's atmosphere, since images at different wavelengths probe different altitudes. New Horizons is providing a wealth of data on this fascinating planet during this last close-up view of Jupiter until the middle of the next decade.

Stratigraphy, age and environments of the late Miocene Mpesida Beds, Tugen Hills, Kenya.

PubMed

Kingston, John D; Fine Jacobs, Bonnie; Hill, Andrew; Deino, Alan

2002-01-01

Interpretations of faunal assemblages from the late Miocene Mpesida Beds in the Tugen Hills of the Central Kenyan Rift Valley have figured prominently in discussions of faunal turnover and establishment of the modern East African communities. These faunal changes have important implications for the divergence of the human lineage from the African apes ca. 8-5 Ma. While fossil material recovered from the Mpesida Beds has traditionally been analyzed collectively, accumulating evidence indicates that Mpesida facies span the 7-6 Ma interval and are scattered more than 25 km along the eastern flanks of the Tugen Hills. Stratigraphic distinctions between Mpesida facies and younger sediments in the sequence, such as the Lukeino Formation, are not yet fully resolved, further complicating temporal assessments and stratigraphic context of Mpesida facies. These issues are discussed with specific reference to exposures of Mpesida facies at Rurmoch, where large fossil tree fragments were swept up in an ancient ash flow. Preserved anatomical features of the fossil wood as well as estimated tree heights suggest a wet, lowland rainforest in this portion of the rift valley. Stable isotopic analyses of fossil enamel and paleosol components indicate the presence of more open habitats locally. Overlying air-fall tuffs and epiclastic debris, possibly associated with the ash flow, have yielded an assemblage of vertebrate fossils including two teeth belonging to one of the earliest colombines of typical body size known from Africa, after the rather small Microcolobus. Single-crystal, laser-fusion,(40)Ar/(39)Ar dates from a capping trachyte flow as well as tuffs just below the lava contact indicate an age of greater than 6.37 Ma for the fossil material. Copyright 2002 Academic Press.

Black carbon solar absorption suppresses turbulence in the atmospheric boundary layer.

PubMed

Wilcox, Eric M; Thomas, Rick M; Praveen, Puppala S; Pistone, Kristina; Bender, Frida A-M; Ramanathan, Veerabhadran

2016-10-18

The introduction of cloud condensation nuclei and radiative heating by sunlight-absorbing aerosols can modify the thickness and coverage of low clouds, yielding significant radiative forcing of climate. The magnitude and sign of changes in cloud coverage and depth in response to changing aerosols are impacted by turbulent dynamics of the cloudy atmosphere, but integrated measurements of aerosol solar absorption and turbulent fluxes have not been reported thus far. Here we report such integrated measurements made from unmanned aerial vehicles (UAVs) during the CARDEX (Cloud Aerosol Radiative Forcing and Dynamics Experiment) investigation conducted over the northern Indian Ocean. The UAV and surface data reveal a reduction in turbulent kinetic energy in the surface mixed layer at the base of the atmosphere concurrent with an increase in absorbing black carbon aerosols. Polluted conditions coincide with a warmer and shallower surface mixed layer because of aerosol radiative heating and reduced turbulence. The polluted surface mixed layer was also observed to be more humid with higher relative humidity. Greater humidity enhances cloud development, as evidenced by polluted clouds that penetrate higher above the top of the surface mixed layer. Reduced entrainment of dry air into the surface layer from above the inversion capping the surface mixed layer, due to weaker turbulence, may contribute to higher relative humidity in the surface layer during polluted conditions. Measurements of turbulence are important for studies of aerosol effects on clouds. Moreover, reduced turbulence can exacerbate both the human health impacts of high concentrations of fine particles and conditions favorable for low-visibility fog events.

Black carbon solar absorption suppresses turbulence in the atmospheric boundary layer

PubMed Central

Wilcox, Eric M.; Thomas, Rick M.; Praveen, Puppala S.; Pistone, Kristina; Bender, Frida A.-M.; Ramanathan, Veerabhadran

2016-01-01

The introduction of cloud condensation nuclei and radiative heating by sunlight-absorbing aerosols can modify the thickness and coverage of low clouds, yielding significant radiative forcing of climate. The magnitude and sign of changes in cloud coverage and depth in response to changing aerosols are impacted by turbulent dynamics of the cloudy atmosphere, but integrated measurements of aerosol solar absorption and turbulent fluxes have not been reported thus far. Here we report such integrated measurements made from unmanned aerial vehicles (UAVs) during the CARDEX (Cloud Aerosol Radiative Forcing and Dynamics Experiment) investigation conducted over the northern Indian Ocean. The UAV and surface data reveal a reduction in turbulent kinetic energy in the surface mixed layer at the base of the atmosphere concurrent with an increase in absorbing black carbon aerosols. Polluted conditions coincide with a warmer and shallower surface mixed layer because of aerosol radiative heating and reduced turbulence. The polluted surface mixed layer was also observed to be more humid with higher relative humidity. Greater humidity enhances cloud development, as evidenced by polluted clouds that penetrate higher above the top of the surface mixed layer. Reduced entrainment of dry air into the surface layer from above the inversion capping the surface mixed layer, due to weaker turbulence, may contribute to higher relative humidity in the surface layer during polluted conditions. Measurements of turbulence are important for studies of aerosol effects on clouds. Moreover, reduced turbulence can exacerbate both the human health impacts of high concentrations of fine particles and conditions favorable for low-visibility fog events. PMID:27702889

Contrasting sea-ice and open-water boundary layers during melt and freeze-up seasons: Some result from the Arctic Clouds in Summer Experiment.

NASA Astrophysics Data System (ADS)

Tjernström, Michael; Sotiropoulou, Georgia; Sedlar, Joseph; Achtert, Peggy; Brooks, Barbara; Brooks, Ian; Persson, Ola; Prytherch, John; Salsbury, Dominic; Shupe, Matthew; Johnston, Paul; Wolfe, Dan

2016-04-01

With more open water present in the Arctic summer, an understanding of atmospheric processes over open-water and sea-ice surfaces as summer turns into autumn and ice starts forming becomes increasingly important. The Arctic Clouds in Summer Experiment (ACSE) was conducted in a mix of open water and sea ice in the eastern Arctic along the Siberian shelf during late summer and early autumn 2014, providing detailed observations of the seasonal transition, from melt to freeze. Measurements were taken over both ice-free and ice-covered surfaces, offering an insight to the role of the surface state in shaping the lower troposphere and the boundary-layer conditions as summer turned into autumn. During summer, strong surface inversions persisted over sea ice, while well-mixed boundary layers capped by elevated inversions were frequent over open-water. The former were often associated with advection of warm air from adjacent open-water or land surfaces, whereas the latter were due to a positive buoyancy flux from the warm ocean surface. Fog and stratus clouds often persisted over the ice, whereas low-level liquid-water clouds developed over open water. These differences largely disappeared in autumn, when mixed-phase clouds capped by elevated inversions dominated in both ice-free and ice-covered conditions. Low-level-jets occurred ~20-25% of the time in both seasons. The observations indicate that these jets were typically initiated at air-mass boundaries or along the ice edge in autumn, while in summer they appeared to be inertial oscillations initiated by partial frictional decoupling as warm air was advected in over the sea ice. The start of the autumn season was related to an abrupt change in atmospheric conditions, rather than to the gradual change in solar radiation. The autumn onset appeared as a rapid cooling of the whole atmosphere and the freeze up followed as the warm surface lost heat to the atmosphere. While the surface type had a pronounced impact on boundary-layer structure in summer, the surface was often warmer than the atmosphere in autumn, regardless of surface type. Hence the autumn boundary-layer structure was more dependent on synoptic scale meteorology.

Assessment of biomass burning smoke influence on environmental conditions for multiyear tornado outbreaks by combining aerosol-aware microphysics and fire emission constraints

NASA Astrophysics Data System (ADS)

Saide, Pablo E.; Thompson, Gregory; Eidhammer, Trude; da Silva, Arlindo M.; Pierce, R. Bradley; Carmichael, Gregory R.

2016-09-01

We use the Weather Research and Forecasting (WRF) system to study the impacts of biomass burning smoke from Central America on several tornado outbreaks occurring in the U.S. during spring. The model is configured with an aerosol-aware microphysics parameterization capable of resolving aerosol-cloud-radiation interactions in a cost-efficient way for numerical weather prediction (NWP) applications. Primary aerosol emissions are included, and smoke emissions are constrained using an inverse modeling technique and satellite-based aerosol optical depth observations. Simulations turning on and off fire emissions reveal smoke presence in all tornado outbreaks being studied and show an increase in aerosol number concentrations due to smoke. However, the likelihood of occurrence and intensification of tornadoes is higher due to smoke only in cases where cloud droplet number concentration in low-level clouds increases considerably in a way that modifies the environmental conditions where the tornadoes are formed (shallower cloud bases and higher low-level wind shear). Smoke absorption and vertical extent also play a role, with smoke absorption at cloud-level tending to burn-off clouds and smoke absorption above clouds resulting in an increased capping inversion. Comparing these and WRF-Chem simulations configured with a more complex representation of aerosol size and composition and different optical properties, microphysics, and activation schemes, we find similarities in terms of the simulated aerosol optical depths and aerosol impacts on near-storm environments. This provides reliability on the aerosol-aware microphysics scheme as a less computationally expensive alternative to WRF-Chem for its use in applications such as NWP and cloud-resolving simulations.

Assessment of biomass burning smoke influence on environmental conditions for multi-year tornado outbreaks by combining aerosol-aware microphysics and fire emission constraints

PubMed Central

Saide, Pablo E.; Thompson, Gregory; Eidhammer, Trude; da Silva, Arlindo M.; Pierce, R. Bradley; Carmichael, Gregory R.

2018-01-01

We use the WRF system to study the impacts of biomass burning smoke from Central America on several tornado outbreaks occurring in the US during spring. The model is configured with an aerosol-aware microphysics parameterization capable of resolving aerosol-cloud-radiation interactions in a cost-efficient way for numerical weather prediction (NWP) applications. Primary aerosol emissions are included and smoke emissions are constrained using an inverse modeling technique and satellite-based AOD observations. Simulations turning on and off fire emissions reveal smoke presence in all tornado outbreaks being studied and show an increase in aerosol number concentrations due to smoke. However, the likelihood of occurrence and intensification of tornadoes is higher due to smoke only in cases where cloud droplet number concentration in low level clouds increases considerably in a way that modifies the environmental conditions where the tornadoes are formed (shallower cloud bases and higher low-level wind shear). Smoke absorption and vertical extent also play a role, with smoke absorption at cloud-level tending to burn-off clouds and smoke absorption above clouds resulting in an increased capping inversion. Comparing these and WRF-Chem simulations configured with a more complex representation of aerosol size and composition and different optical properties, microphysics and activation schemes, we find similarities in terms of the simulated aerosol optical depths and aerosol impacts on near-storm environments. This provides reliability on the aerosol-aware microphysics scheme as a less computationally expensive alternative to WRF-Chem for its use in applications such as NWP and cloud-resolving simulations. PMID:29619287

Blue Hill Observatory Sunshine - Assessment of Climate Signals in the Longest Continuous Meteorological Record in North America

NASA Astrophysics Data System (ADS)

Magee, N. B.; Finocchio, P.; Melaas, E. K.; Iacono, M. J.

2014-12-01

The Blue Hill Meteorological Observatory occupies a unique place in the history of the American Meteorological Society and the development of atmospheric science. Through its 129-year history, the Observatory has been operated by founder Abbott Lawrence Rotch (1861-1912), Harvard University, and the National Weather Service, and it is presently run by the non-profit Blue Hill Observatory Science Center. While daily temperature and precipitation records are available through the National Climatic Data Center, they do not include the full record of sunshine duration data that were measured using a Campbell-Stokes sunshine recorder. We have recently digitized the Observatory's original daily sunshine archives, and now present the first full collection and analysis of sunshine records extending from 1889 to the present. This data set is unique and salient to modern climate research because the collection represents the earliest and longest continuous measurements of insolation outside of Western Europe. Together the record provides an unprecedented glimpse into regional climate features, as well as important links between global phenomena and regional climate. Analysis reveals long-term fluctuations of cloud-cover and solar radiation, including signals of regional industrialization, global-dimming, volcanic eruptions, the 11-Year Solar Cycle, and the El Niño Southern Oscillation. Shorter period fluctuations include evidence of an intricate annual pattern of sunshine duration and correlations with the Arctic Oscillation, North Atlantic Oscillation, and galactic cosmic rays.

Rate of radial transport of plasma in Saturn’s inner magnetosphere

NASA Astrophysics Data System (ADS)

Chen, Y.; Hill, T. W.

2009-12-01

The Cassini Plasma Spectrometer (CAPS) and the Cassini Magnetospheric Imaging Instrument (MIMI) frequently observe longitudinally localized injection and drift dispersion of hot plasma in Saturn’s magnetosphere. These signatures provide direct evidence for the major convective process in the inner magnetosphere of a rapidly rotating planet, in which the radial transport of plasma comprises hot, tenuous plasma moving inward and cooler, denser plasma moving outward. These injection events have been found to occupy only a small fraction of the total available longitudinal space, indicating that the inflow speed is probably much larger than the outflow speed. We set the local corotation speed as the upper limit of inflow velocities, and deduce the corresponding radial velocities of the outflowing flux tubes by analyzing the width of injection structures and assuming that the total potential drop around a given L-shell is zero. We then estimate an upper limit to the plasma outward mass transport rate, which turns out to be somewhat larger than previous estimates of the Enceladus source rate (e.g., Pontius and Hill, 2006). An important assumption in this study is that the plasma is largely confined to a thin equatorial sheet, and we have applied a centrifugal scale height model developed by Hill and Michel [1976].

MABEL Iceland 2012 Flight Report

NASA Technical Reports Server (NTRS)

Cook, William B.; Brunt, Kelly M.; De Marco, Eugenia L.; Reed, Daniel L.; Neumann, Thomas A.; Markus, Thorsten

2017-01-01

In March and April 2012, NASA conducted an airborne lidar campaign based out of Keflavik, Iceland, in support of Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) algorithm development. The survey targeted the Greenland Ice Sheet, Iceland ice caps, and sea ice in the Arctic Ocean during the winter season. Ultimately, the mission, MABEL Iceland 2012, including checkout and transit flights, conducted 14 science flights, for a total of over 80 flight hours over glaciers, icefields, and sea ice.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information:VIS instrument. Latitude 86.5, longitude 57.4 East (302.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 84.3, Longitude 314.4 East (45.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This week we will be looking at five examples of laminar wind flow on the north polar cap. On Earth, gravity-driven south polar cap winds are termed 'catabatic' winds. Catabatic winds begin over the smooth expanse of the cap interior due to temperature differences between the atmosphere and the surface. Once begun, the winds sweep outward along the surface of the polar cap toward the sea. As the polar surface slopes down toward sealevel, the wind speeds increase. Catabatic wind speeds in the Antartic can reach several hundreds of miles per hour.

In the images of the Martian north polar cap we can see these same type of winds. Notice the streamers of dust moving downslope over the darker trough sides, these streamers show the laminar flow regime coming off the cap. Within the trough we see turbulent clouds of dust, kicked up at the trough base as the winds slow down and enter a chaotic flow regime.

The horizontal lines in these images are due to framelet overlap and lighting conditions over the bright polar cap.

Image information: VIS instrument. Latitude 84.2, Longitude 57.4 East (302.6 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Role of clouds, aerosols, and aerosol-cloud interaction in 20th century simulations with GISS ModelE2

NASA Astrophysics Data System (ADS)

Nazarenko, L.; Rind, D. H.; Bauer, S.; Del Genio, A. D.

2015-12-01

Simulations of aerosols, clouds and their interaction contribute to the major source of uncertainty in predicting the changing Earth's energy and in estimating future climate. Anthropogenic contribution of aerosols affects the properties of clouds through aerosol indirect effects. Three different versions of NASA GISS global climate model are presented for simulation of the twentieth century climate change. All versions have fully interactive tracers of aerosols and chemistry in both the troposphere and stratosphere. All chemical species are simulated prognostically consistent with atmospheric physics in the model and the emissions of short-lived precursors [Shindell et al., 2006]. One version does not include the aerosol indirect effect on clouds. The other two versions include a parameterization of the interactive first indirect aerosol effect on clouds following Menon et al. [2010]. One of these two models has the Multiconfiguration Aerosol Tracker of Mixing state (MATRIX) that permits detailed treatment of aerosol mixing state, size, and aerosol-cloud activation. The main purpose of this study is evaluation of aerosol-clouds interactions and feedbacks, as well as cloud and aerosol radiative forcings, for the twentieth century climate under different assumptions and parameterizations for aerosol, clouds and their interactions in the climate models. The change of global surface air temperature based on linear trend ranges from +0.8°C to +1.2°C between 1850 and 2012. Water cloud optical thickness increases with increasing temperature in all versions with the largest increase in models with interactive indirect effect of aerosols on clouds, which leads to the total (shortwave and longwave) cloud radiative cooling trend at the top of the atmosphere. Menon, S., D. Koch, G. Beig, S. Sahu, J. Fasullo, and D. Orlikowski (2010), Black carbon aerosols and the third polar ice cap, Atmos. Chem. Phys., 10,4559-4571, doi:10.5194/acp-10-4559-2010. Shindell, D., G. Faluvegi, N. Unger, E. Aguilar, G.A. Schmidt, D.M. Koch, S.E. Bauer, and J.R. Miller (2006), Simulations of preindustrial, present-day, and 2100 conditions in the NASA GISS composition and climate model G-PUCCINI, Atmos. Chem. Phys., 6, 4427-4459.

Space Weather Connections to Clouds and Climate

NASA Astrophysics Data System (ADS)

Tinsley, B. A.

2004-12-01

There is now a considerable amount of observational data and theoretical work pointing to a link between space weather and atmospheric electricity, and then between atmospheric electricity and cloud cover and precipitation, which ultimately affect climate and the biosphere. Studies so far have been largely confined to the Earth, but may be applicable to all planets with clouds in their atmospheres. The current density Jz, that is the return current flowing downward through clouds in the global circuit, is modulated by the galactic cosmic ray flux; by solar energetic particles; by the dawn-dusk polar cap potential difference; and by the precipitation of relativistic electrons from the radiation belts. The flow of Jz through clouds generates unipolar space charge, which is positive at cloud tops and negative at cloud base. This charge attaches to aerosol particles, and affects their interaction with other particles and droplets. Ultrafine aerosol particles are formed around ions and are preserved from scavenging on background aerosols, and preserved for growth by vapor deposition, by space charge at the bases and tops of layer clouds. There is electro-preservation of both ultrafines and of existing CCN that leads to increases in CCN concentration, and increases in cloud cover and reduction in both droplet size and precipitation by the `indirect aerosol effect'. For cold clouds and larger aerosol particles that act as ice forming nuclei, the rate of scavenging of the IFN by large supercooled droplets varies with space charge. Changes in space weather affect both ion production and Jz in planetary atmospheres. In addition, changes in cosmic ray flux affect conductivity within thunderclouds and may affect the output of the thundercloud generators in the global circuit. Thus all four processes, (a) ion-induced nucleation, (b) electro-preservation of leading to increases in CCN concentration and the indirect aerosol effect, (c) contact ice nucleation affecting the production of ices, (d) cosmic ray effects on the generators of the global circuit, are potential links between space weather and life on planets.

View of portion of Western United States as seen by Skylab

NASA Image and Video Library

1974-01-10

SL4-139-4040 (10 Jan. 1974) --- An oblique view of a portion of the Western United States, as photographed from the Skylab space station in Earth orbit by one of the Skylab 4 crewmen. The camera used was a hand-held 70mm Hasselblad, with SO-368 medium-speed Ektachrome film. This photograph is one of a stereo pair (the other being 4039) taken to support the hydrological studies of the changing snow patterns in several watersheds. Stereo analysis will enable snow to be distinguished from clouds quantitatively. In a qualitative sense, the clouds are the fuzzy white, whereas the snow is distinct white. The area covered is from the Colorado Springs, Colorado area at the south to (and beyond) the Black Hills, South Dakota area. The Black Forest between Colorado Springs and Denver is evident as are the mountains west of these cities. South Park, west of Colorado Springs, and the South Platte River running north and east from Denver are two other conspicuous features. Photo credit: NASA

Visualizing nD Point Clouds as Topological Landscape Profiles to Guide Local Data Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oesterling, Patrick; Heine, Christian; Weber, Gunther H.

2012-05-04

Analyzing high-dimensional point clouds is a classical challenge in visual analytics. Traditional techniques, such as projections or axis-based techniques, suffer from projection artifacts, occlusion, and visual complexity.We propose to split data analysis into two parts to address these shortcomings. First, a structural overview phase abstracts data by its density distribution. This phase performs topological analysis to support accurate and non-overlapping presentation of the high-dimensional cluster structure as a topological landscape profile. Utilizing a landscape metaphor, it presents clusters and their nesting as hills whose height, width, and shape reflect cluster coherence, size, and stability, respectively. A second local analysis phasemore » utilizes this global structural knowledge to select individual clusters or point sets for further, localized data analysis. Focusing on structural entities significantly reduces visual clutter in established geometric visualizations and permits a clearer, more thorough data analysis. In conclusion, this analysis complements the global topological perspective and enables the user to study subspaces or geometric properties, such as shape.« less

Seasonal Changes in Mars' North Polar Ice Cap

NASA Technical Reports Server (NTRS)

1997-01-01

These images, which seem to have been taken while NASA's Hubble Space Telescope (HST) was looking directly down on the Martian North Pole, were actually created by assembling mosaics of three sets of images taken by HST in October, 1996 and in January and March, 1997 and projecting them to appear as they would if seen from above the pole. This first mosaic is a view which could not actually be seen in nature because at this season a portion of the pole would have actually been in shadow; the last view, taken near the summer solstice, would correspond to the Midnight Sun on Earth with the pole fully illuminated all day. The resulting polar maps begin at 50 degrees N latitude and are oriented with 0 degrees longitude at the 12 o'clock position. This series of pictures captures the seasonal retreat of Mars' north polar cap.

October 1996 (early spring in the Northern hemisphere): In this map, assembled from images obtained between Oct. 8 and 15, the cap extends down to 60 degrees N latitude, nearly it's maximum winter extent. (The notches are areas where Hubble data were not available). A thin, comma-shaped cloud of dust can be seen as a salmon-colored crescent at the 7 o'clock position. The cap is actually fairly circular about the geographic pole at this season; the bluish 'knobs' where the cap seems to extend further are actually clouds that occurred near the edges of the three separate sets of images used to make the mosaic.

January 1997 (mid-spring): Increased warming as spring progresses in the northern hemisphere has sublimated the carbon dioxide ice and frost below 70 degrees north latitude. The faint darker circle inside the cap boundary marks the location of circumpolar sand dunes (see March '97 map); these dark dunes are warmed more by solar heating than are the brighter surroundings, so the surface frost sublimates from the dunes earlier than from the neighboring areas. Particularly evident is the marked hexagonal shape of the polar cap at this season, noted previously by HST in 1995 and Mariner 9 in 1972; this may be due to topography, which isn't well known, or to wave structure in the circulation. This map was assembled from WFPC2 images obtained between Dec. 30, 1996 and Jan. 4, 1997.

March 30, 1997 (early summer): The cap has fully retreated to its remnant core of water-ice. This residual cap is actually almost cut into two by a large, horn-shaped canyon called Chasma Borealis which is cut deeply into the polar terrain. The HST images also reveal a curious layered terrain which is evidence of past climatic changes on Mars. The sublimation of all of the carbon dioxide has exposed the ring of dark sand dunes which encircle the North Polar Cap. Outliers of ice persist south of the polar sand sea (between the 3 o'clock and 9 o'clock positions). The bright circular features at 3, 6, and 9 o'clock are ice-filled craters.

All images were taken with the Wide Field and Planetary Camera 2. The color is constructed from images taken in red (673 nm) , blue (410 nm) and green (502 nm) light. The resolution at the North Pole ranges from about 115 km/pixel in October '96 to about 45 km/pixel in March '97.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

Slumps and Fog in Valles Marineris

NASA Astrophysics Data System (ADS)

Ojha, L.; Chojnacki, M.; Toigo, A. D.; McDonald, G. D.; Wolff, M. J.; Leung, C. W. S.

2016-12-01

The first spectral evidence for H2O ice clouds on Mars came from the interferometer spectrometer on board the Mariner 9 spacecraft. Water ice clouds on Mars form by freezing of atmospheric water vapor, of which the main surface source is the seasonal sublimation of the polar caps, and have been observed around the Tharsis volcanoes, Olympus Mons, Alba Patera, Valles Marineris (VM) and the southern highlands. Cloud activity in some of these regions display a seasonal trend, where the cloud area increases in warmer seasons, and decreases during colder seasons. The atmospheric hazes in VM are relatively small in areal extent, confined within canyon topography, and are difficult to replicate in models of global or regional vapor transport, indicating that they may be locally sourced. This distinguishes the VM hazes from the global-scale clouds. Spectral data from the Planetary Fourier Spectrometer onboard the Mars Express orbiter have been reported as consistent with water ice in the atmospheric fog, however results from Mars Express favored dust as responsible for low-elevation hazes. Here we report observations and spectroscopic analyses of low elevation haze in Juventae Chasma, which are spatially correlated with locations of seasonal flows thought to be caused by briny liquid water. Furthermore, we report the seasonality of the haze and explore its potential role in the creation of contemporary mass-wasting features on Mars.

Using Amazon's Elastic Compute Cloud to dynamically scale CMS computational resources

NASA Astrophysics Data System (ADS)

Evans, D.; Fisk, I.; Holzman, B.; Melo, A.; Metson, S.; Pordes, R.; Sheldon, P.; Tiradani, A.

2011-12-01

Large international scientific collaborations such as the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider have traditionally addressed their data reduction and analysis needs by building and maintaining dedicated computational infrastructure. Emerging cloud computing services such as Amazon's Elastic Compute Cloud (EC2) offer short-term CPU and storage resources with costs based on usage. These services allow experiments to purchase computing resources as needed, without significant prior planning and without long term investments in facilities and their management. We have demonstrated that services such as EC2 can successfully be integrated into the production-computing model of CMS, and find that they work very well as worker nodes. The cost-structure and transient nature of EC2 services makes them inappropriate for some CMS production services and functions. We also found that the resources are not truely "on-demand" as limits and caps on usage are imposed. Our trial workflows allow us to make a cost comparison between EC2 resources and dedicated CMS resources at a University, and conclude that it is most cost effective to purchase dedicated resources for the "base-line" needs of experiments such as CMS. However, if the ability to use cloud computing resources is built into an experiment's software framework before demand requires their use, cloud computing resources make sense for bursting during times when spikes in usage are required.

Photometric properties of Triton hazes

NASA Technical Reports Server (NTRS)

Hillier, J.; Veverka, J.

1994-01-01

Voyager imaging observations of Triton have been used to investigate the characteristics of the atmospheric hazes on Triton at three wavelengths: violet (0.41 micrometers), blue (0.48 micrometers), and green (0.56 micrometers). The globally averaged optical depth is wavelength dependent, varying from 0.034 in green to 0.063 in violet. These photometric results are dominated by the properties of localized discrete clouds rather than by those of the thinner, more widespread haze known to occur on Triton. The cloud particles are bright, with single-scattering albedos near unity at all three wavelengths, suggestive of a transparent icy condensate. The asymmetry parameter (+0.6) and the wavelength dependence of the optical depth both indicate cloud particles 0.2-0.4 micrometers in radius. The clouds are concentrated at 50-60 deg S latitude, where opacities up to three times the global average are observed. This is the same latitude region where most of the evidence for current surface activity is found, suggesting that the clouds may be related to the plumes or at least to some process connected with the sublimation of the south polar cap. The effects of possible temporal variations in the haze opacity are examined. Increases in the haze opacity tend to redden Triton. However, the degree of reddening is not sufficient to explain the full range of observed changed in Triton over the past decade; variations in the surface properties appear to be necessary.

Implications of summertime marine stratocumulus on the North American climate

NASA Technical Reports Server (NTRS)

Clark, John H. E.

1994-01-01

This study focuses on the effects of summertime stratocumulus over the eastern Pacific. This cloud is linked to the semi-permanent sub-tropical highs that dominate the low-level circulation over the Pacific and Atlantic. Subsidence on the eastern flank of these highs creates an inversion based about 800 m above sea level that caps moist air near the surface. This air overlies cool waters driven by upwelling along the coastal regions of North America. Strong surface north-westerlies mix the boundary layer enough to saturate the air just below the capping inversion. Widespread stratocumulus is thus formed. All calculations were carried out using the GENESIS general circulation model that was run at MSFC. Among the more important properties of the model is that it includes radiative forcing due to absorption of solar radiation and the emission of infrared radiation, interactive clouds (both stratocumulus and cumulus types), exchanges of heat and moisture with the lower boundary. Clouds are interactive in the sense that they impact the circulation by modifying the fields of radiative heating and turbulent fluxes of heat and moisture in the boundary layer. In turn, clouds are modified by the winds through the advection of moisture. In order to isolate the effects of mid- and high-latitude stratocumulus, two runs were made with the model: one with and the other without stratocumulus. The runs were made for a year, but with perpetual July conditions, i.e., solar forcing was fixed. The diurnal solar cycle, however, was allowed for. The sea surface temperature distribution was fixed in both runs to represent climatological July conditions. All dependent variables were represented at 12 surfaces of constant sigma = p/p(sub O), where p is pressure and p(sub O) is surface pressure. To facilitate analysis, model output was transformed to constant pressure surfaces. Structures no smaller in size than 7.5 degrees longitude and 4.5 degrees in latitude were resolved. Smaller features of the circulation were parameterized. The model thus captures synoptic- and planetary-scale circulation features.

Cooperative Atmosphere-Surface Exchange Study-1999.

NASA Astrophysics Data System (ADS)

Moeng, Chin-Hoh; Poulos, Gregory S.; Lemone, Margaret A.

2003-10-01

Surface-station, radiosonde, and Doppler minisodar data from the Cooperative Atmosphere-Surface Exchange Study-1997 (CASES-97) field project, collected in a 60-km-wide array in the lower Walnut River watershed (terrain variation 150 m) southeast of Wichita, Kansas, are used to study the relationship of the change of the 2-m potential temperature 2m with station elevation ze, 2m/ze ,ze to the ambient wind and thermal stratification /z ,z during fair-weather nights. As in many previous studies, predawn 2m varies linearly with ze, and ,ze ,z over a depth h that represents the maximum elevation range of the stations. Departures from the linear 2m-elevation relationship (,ze line) are related to vegetation (cool for vegetation, warm for bare ground), local terrain (drainage flows from nearby hills, although a causal relationship is not established), and the formation of a cold pool at lower elevations on some days.The near-surface flow and its evolution are functions of the Froude number Fr = S/(Nh), where S is the mean wind speed from the surface to h, and N is the corresponding Brunt-Väisälä frequency. The near-surface wind is coupled to the ambient flow for Fr = 3.3, based on where the straight line relating ,ze to ln Fr intersects the ln Fr axis. Under these conditions, 2m is constant horizontally even though ,z > 0, suggesting that near-surface air moves up- and downslope dry adiabatically. However, 2m cools (or warms) everywhere at the same rate. The lowest Froude numbers are associated with drainage flows, while intermediate values characterize regimes with intermediate behavior. The evolution of 2m horizontal variability σ through the night is also a function of the predawn Froude number. For the nights with the lowest Fr, the σ maximum occurs in the last 1-3 h before sunrise. For nights with Fr 3.3 (,ze 0) and for intermediate values, σ peaks 2-3 h after sunset. The standard deviations relative to the ,ze line reach their lowest values in the last hours of darkness. Thus, it is not surprising that the relationships of ,ze to Fr and ,z based on data through the night show more scatter, and ,ze 0.5,z in contrast to the predawn relationship. However, ,ze 0 for ln Fr = 3.7, a value similar to that just before sunrise.A heuristic Lagrangian parcel model is used to explain the horizontal uniformity of time-evolving 2m when the surface flow is coupled with the ambient wind, as well as both the linear variation of 2m with elevation and the time required to reach maximum values of σ under drainage-flow conditions.

The 1946 Unimak Tsunami Earthquake Area: revised tectonic structure in reprocessed seismic images and a suspect near field tsunami source

USGS Publications Warehouse

Miller, John J.; von Huene, Roland E.; Ryan, Holly F.

2014-01-01

In 1946 at Unimak Pass, Alaska, a tsunami destroyed the lighthouse at Scotch Cap, Unimak Island, took 159 lives on the Hawaiian Islands, damaged island coastal facilities across the south Pacific, and destroyed a hut in Antarctica. The tsunami magnitude of 9.3 is comparable to the magnitude 9.1 tsunami that devastated the Tohoku coast of Japan in 2011. Both causative earthquake epicenters occurred in shallow reaches of the subduction zone. Contractile tectonism along the Alaska margin presumably generated the far-field tsunami by producing a seafloor elevation change. However, the Scotch Cap lighthouse was destroyed by a near-field tsunami that was probably generated by a coeval large undersea landslide, yet bathymetric surveys showed no fresh large landslide scar. We investigated this problem by reprocessing five seismic lines, presented here as high-resolution graphic images, both uninterpreted and interpreted, and available for the reader to download. In addition, the processed seismic data for each line are available for download as seismic industry-standard SEG-Y files. One line, processed through prestack depth migration, crosses a 10 × 15 kilometer and 800-meter-high hill presumed previously to be basement, but that instead is composed of stratified rock superimposed on the slope sediment. This image and multibeam bathymetry illustrate a slide block that could have sourced the 1946 near-field tsunami because it is positioned within a distance determined by the time between earthquake shaking and the tsunami arrival at Scotch Cap and is consistent with the local extent of high runup of 42 meters along the adjacent Alaskan coast. The Unimak/Scotch Cap margin is structurally similar to the 2011 Tohoku tsunamigenic margin where a large landslide at the trench, coeval with the Tohoku earthquake, has been documented. Further study can improve our understanding of tsunami sources along Alaska’s erosional margins.

Cassini Imaging of Titan’s North Polar Cloud With the Visual and Infrared Mapping Spectrometer

NASA Astrophysics Data System (ADS)

Le Mouélic, S.; Rannou, P.; Rodriguez, S.; Sotin, C.; Le Corre, L.; Barnes, J. W.; Brown, R. H.; Griffith, C. A.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P.

2009-12-01

We report on the Visual and Infrared Mapping Spectrometer (VIMS) observations of a giant cloud over the north pole of Titan. Griffith et al. [Science, 2006] described the first evidence of a north polar feature having the form of an ubiquitous bright band at 51° to 68°N in VIMS images acquired in December 2004, August and September 2005. Rodriguez et al. [Nature, 2009] systematically detect spectral signatures of clouds with VIMS at latitudes higher than 50°N between July 2004 and December 2007, with no attempt to show the structure of each individual cloud. The first good opportunity to observe the fully illuminated north pole, that we described here, occurred on December 28, 2006. The north cloud was then continuously monitored in various geometries during 3 years after its first discovery. This cloud shows much less signal at 5-µm than southern and tropical clouds which are thought to be composed of liquid/solid methane. This indicates a lower backscattering at 5-µm. It is consistent with clouds composed of micron-sized particles made of solid ethane. A radiative transfer model in spherical geometry (SPDISORT) shows that it is found at an altitude between 30 and 40 km. This observation confirms the IPSL Titan global circulation model of Rannou et al. [Science 2006] that predicted the formation of large polar ethane clouds due to the downwelling of atmospheric streams exactly at the same latitudes. The limits of the observed northern cloud between 50-60°N corresponds to the limit between filled and dry lakes as observed by the RADAR of Cassini. The cloud cover appears less widespread in the last observations, which could indicate that it is progressively vanishing. This is also in agreement with the predictions of the IPSL general circulation model as we approach the equinox in August 2009. Dedicated observations by the Cassini spacecraft during the extended mission possibly up to 2017 should allow the observation of the forthcoming seasonal circulation turnover, with possibly the complete disappearance of this type of cloud that caps the north pole.

Recession of the Northern polar cap from the PFS Mars Express observations

NASA Astrophysics Data System (ADS)

Zasova, L. V.; Formisano, V.; Moroz, V. I.; Giuranna, M.; Grassi, D.; Hansen, G.; Ignatiev, N. I.; Maturilli, A.; Pfs Team

Planetary Fourier Spectrometer (PFS) has two spectral channels, devoted to the thermal and solar reflected spectral range investigations. The first observations by PFS of the Northern hemisphere ,which includes the North pole, occurred at Ls= 342 (northern winter). Surface temperature alone the orbit shows that the CO2 ice polar cap, where the surface temperature is found around 150K and below, is extended down to about 62 N. The spectra at latitudes above 80 N are obtained at polar darkness and at latitudes below 80 at illumination by the low Sun. Retrieved temperature profiles of the atmosphere at darkness show that temperature of the atmosphere is low enough to allow the CO2 condensation up to about 25 km. Between 70 and 80 latitude the upper levels of the atmosphere are heated by the Sun, but condensation of the CO2 may occur in the near surface layer below 5 km. The water ice clouds exist at lower latitudes with maximum opacity at the edge of the polar cap. More detailed investigation of the data obtained in winter as well as of the measurements in the northern spring will be presented.

Copernicus observational searches for OH and H/sub 2/O in diffuse clouds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, W.H.; Snow, T.P. Jr.

1979-03-01

An intensive search for OH and H/sub 2/O in the directions of sigma Sco, ..cap alpha.. Cam, and omicron Per was undertaken with the Copernicus satellite. Multiple scans were carried out over the wavelength region for the expected absorption features due to the OH D--X and H/sub 2/O C--X transitions. The feature due to OH was possibly detected toward sigma Sco, and only an upper limit can be given toward ..cap alpha.. Cam. H/sub 2/O was not detected in any of the stars at the signal level accumulated. The OH abundance toward sigma Sco and the respective lower limits formore » the OH/H/sub 2/O ratios are discussed with regard to the extant models for the steady-state abundances of OH and H/sub 2/O, and shown not to be inconsistent with ion-molecule schemes.« less

Soufriere Hills Volcano Resumes Activity

NASA Image and Video Library

2017-12-08

A massive eruption of Montserrat’s Soufrière Hills Volcano covered large portions of the island in debris. The eruption was triggered by a collapse of Soufrière Hills’ summit lava dome on February 11, 2010. Pyroclastic flows raced down the northern flank of the volcano, leveling trees and destroying buildings in the village of Harris, which was abandoned after Soufrière Hills became active in 1995. The Montserrat Volcano Observatory reported that some flows, about 15 meters (49 feet) thick, reached the sea at Trant’s Bay. These flows extended the island’s coastline up to 650 meters (2,100 feet). These false-color satellite images show the southern half of Montserrat before and after the dome collapse. The top image shows Montserrat on February 21, 2010, just 10 days after the event. For comparison, the bottom image shows the same area on March 17, 2007. Red areas are vegetated, clouds are white, blue/black areas are ocean water, and gray areas are covered by flow deposits. Fresh deposits tend to be lighter than older deposits. On February 21, the drainages leading down from Soufrière Hills, including the White River Valley, the Tar River Valley, and the Belham River Valley, were filled with fresh debris. According to the Montserrat Volcano Observatory, pyroclastic flows reached the sea through Aymers Ghaut on January 18, 2010, and flows entered the sea near Plymouth on February 5, 2010. NASA Earth Observatory image by Robert Simmon, using data from the NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Robert Simmon. To read more go to: earthobservatory.nasa.gov/IOTD/view.php?id=42792 NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe. Follow us on Twitter Join us on Facebook

Inventory of forest and rangeland and detection of forest stress

NASA Technical Reports Server (NTRS)

Heller, R. C.; Aldrich, R. C.; Weber, F. P.; Driscoll, R. S. (Principal Investigator)

1972-01-01

There are no author-identified significant results in this report. Some ERTS-1 imagery has been received for each of the test sites: Black Hills, Atlanta, and Manitou. Only small portions of each site are covered and clouds have precluded capturing good imagery over the center of each site. Discoloration infestations of ponderosa pine are being located and sized on CIR transparencies. A computer program was completed from microdensitometer scans of CIR photos which maps areas of an image which are spectrally similar. Decided differences between forest types are present as well as differences between forest and other vegetative and nonvegetative land classes.

Imaging open-path Fourier transform infrared spectrometer for 3D cloud profiling

NASA Astrophysics Data System (ADS)

Rentz Dupuis, Julia; Mansur, David J.; Vaillancourt, Robert; Carlson, David; Evans, Thomas; Schundler, Elizabeth; Todd, Lori; Mottus, Kathleen

2009-05-01

OPTRA is developing an imaging open-path Fourier transform infrared (I-OP-FTIR) spectrometer for 3D profiling of chemical and biological agent simulant plumes released into test ranges and chambers. An array of I-OP-FTIR instruments positioned around the perimeter of the test site, in concert with advanced spectroscopic algorithms, enables real time tomographic reconstruction of the plume. The approach is intended as a referee measurement for test ranges and chambers. This Small Business Technology Transfer (STTR) effort combines the instrumentation and spectroscopic capabilities of OPTRA, Inc. with the computed tomographic expertise of the University of North Carolina, Chapel Hill.

Exploring Mars in 1988

NASA Astrophysics Data System (ADS)

Beish, J. D.; Parker, D. C.

1988-04-01

During September 19-26, 1988, Mars will be 23.8 arcsec wide; this is fully 95 percent as large as Mars can ever possibly become, and only 1 arcsec smaller than it attained during the last very favorable apparition, in 1971. In the case of the 1988 apparition, Mars will be 20 deg higher in the sky than in either 1971 or 1986, offering observers in the Northern Hemisphere a much better view. The south polar cap is discussed as well as clouds and hazes, yellow dust storms, and seasonable trends.

Panoramic View of the Andes Mountains, Chile and Argentina

NASA Technical Reports Server (NTRS)

1992-01-01

This panoramic view of the Andes Mountains of Chile and Argentina (24.5S, 69.5W) is dominated by the yellows and browns of the coastal Atacama Desert and the full width of the Andes altiplano, about 300 miles. Winter snow can be seen capping the 22,000 to 23,000 ft. peaks of the Andes. Wisps of cirrus clouds lie over the altiplano and offshore fog obscures the coast. In the distance, the low Chaco Plain appears green with pastures and agriculture.

Far-Field Simulation of the Hawaiian Wake: Sea Surface Temperature and Orographic Effects(.

NASA Astrophysics Data System (ADS)

Hafner, Jan; Xie, Shang-Ping

2003-12-01

Recent satellite observations reveal far-reaching effects of the Hawaiian Islands on surface wind, cloud, ocean current, and sea surface temperature (SST) that extend leeward over an unusually long distance (>1000 km). A three-dimensional regional atmospheric model with full physics is used to investigate the cause of this long wake. While previous wind wake studies tend to focus on regions near the islands, the emphasis here is the far-field effects of SST and orography well away from the Hawaiian Islands. In response to an island-induced SST pattern, the model produces surface wind and cloud anomaly patterns that resemble those observed by satellites. In particular, anomalous surface winds are found to converge onto a zonal band of warmer water, with cloud liquid water content enhanced over it but reduced on the northern and southern sides. In the vertical, a two-cell meridional circulation develops of a baroclinic structure with the rising motion and thicker clouds over the warm water band. The model response in the wind and cloud fields supports the hypothesis that ocean atmosphere interaction is crucial for sustaining the island effects over a few thousand kilometers.Near Hawaii, mountains generate separate wind wakes in the model lee of individual islands as observed by satellites. Under orographic forcing, the model simulates the windward cloud line and the southwest-tilted cloud band leeward of the Big Island. In the far field, orographically induced wind perturbations are found to be in geostrophic balance with pressure anomalies, indicative of quasigeostrophic Rossby wave propagation. A shallow-water model is developed for disturbances trapped in the inversion-capped planetary boundary layer. The westward propagation of Rossby waves is found to increase the wake length significantly, consistent with the three-dimensional simulation.

The role of mountain precipitation as a drought buffer in Puerto Rico: Assessing natural systems' resilience to change

NASA Astrophysics Data System (ADS)

Scholl, M. A.; Clark, K. E.; Van Beusekom, A.; Shanley, J. B.; Torres-Sanchez, A.; Murphy, S. F.; Gonzalez, G.

2017-12-01

Like many island and coastal areas, the Luquillo Mountains of Puerto Rico receive orographic precipitation (rain and cloud water), maintaining headwater streamflow and allowing diverse forest ecosystems to thrive. Although rainfall from regional-scale convective systems is greater in volume, multiple lines of evidence (stable isotope tracers; precipitation amount, frequency, and intensity; cloud immersion; regional cloud dynamics; weather analysis) show that trade-wind orographic precipitation contributes significantly to streamflow, soil water, and shallow groundwater. Ceilometer data and time-lapse photography of cloud-immersed conditions at the mountain indicated a seasonally invariant, sustained overnight regime of cloud water precipitation, in addition to the abundant rainfall in the mountains. Rising ocean temperatures and a warming tropical climate lead to questions about persistence of the trade-wind associated orographic precipitation and the resilience of similar mountain ecosystems to change. Projections for Caribbean climate change include amplification of trade winds; less frequent, more intense large convective systems; and a warming ocean. These may have opposing effects on mountain precipitation, increasing uncertainty about processes that mitigate drought. Field studies provide insights regarding these questions. Ceilometer and satellite observations showed cloud base is higher over the mountains than in the surrounding Caribbean region; with the trade-wind inversion cap, further rise in cloud base may produce shallower clouds and reduced precipitation. We analyzed the February-October 2015 drought, characterized by strong El Niño conditions, an absence of tropical storm systems, and reduced convection in easterly waves. Combined δ2H, δ18O and d-excess signatures of streamflow indicated precipitation was derived from shallow convective systems, trade-wind showers and cloud water. During severe drought on the island, streamflow-sustaining rainfall at the mountain station at 640 m persisted, albeit with 19% lower frequency and 52% fewer large (>10 mm) rain events than the 20-year average. Clearly, resilience of the mountain forest ecosystem and of streamflow to drought periods depends on orographic precipitation.

Comparison of Dawn and Dusk Precipitating Electron Energy Populations Shortly After the Initial Shock for the January 10th, 1997 Magnetic Cloud

NASA Technical Reports Server (NTRS)

Spann, J.; Germany, G.; Swift, W.; Parks, G.; Brittnacher, M.; Elsen, R.

1997-01-01

The observed precipitating electron energy between 0130 UT and 0400 UT of January 10 th, 1997, indicates that there is a more energetic precipitating electron population that appears in the auroral oval at 1800-2200 UT at 030) UT. This increase in energy occurs after the initial shock of the magnetic cloud reaches the Earth (0114 UT) and after faint but dynamic polar cap precipitation has been cleared out. The more energetic population is observed to remain rather constant in MLT through the onset of auroral activity (0330 UT) and to the end of the Polar spacecraft apogee pass. Data from the Ultraviolet Imager LBH long and LBH short images are used to quantify the average energy of the precipitating auroral electrons. The Wind spacecraft located about 100 RE upstream monitored the IMF and plasma parameters during the passing of the cloud. The affects of oblique angle viewing are included in the analysis. Suggestions as to the source of this hot electron population will be presented.

Southern Half of Spirit's 'Bonestell' Panorama

NASA Technical Reports Server (NTRS)

2008-01-01

This 180-degree panorama shows the southward vista from the location where Spirit is spending its third Martian winter inside Mars' Gusev Crater. The rover's overwintering location is on the northern edge of a low plateau informally called 'Home Plate,' which is about 80 meters or 260 feet in diameter.

This view combines 168 different exposures taken with Spirit's panoramic Camera (Pancam) 42 pointings with 4 filters at each pointing. Spirit took the first of these frames during the mission's 1,477th Martian day, or sol, (February 28, 2008) two weeks after the rover made its last move to reach the location where it would stop driving for the winter. Solar energy at Gusev Crater is so limited during the Martian winter that Spirit does not generate enough electricity to drive, nor even enough to take many images per day. The last frame for this mosaic was taken on Sol 1599 (July 2, 2008). The rover team plans for Spirit to finish taking images for the northern half of the scene during the Martian spring.

The northwestern edge of Home Plate is visible in the right foreground. The blockier, more sharply shadowed texture there is layered sandstone whose layering is tilted inward toward the edge of the Home Plate platform. A dark rock on top of Home Plate in that area is a porous volcanic basalt unlike rocks nearby. The northeastern edge of Home Plate is visible in the left foreground. Spirit first climbed onto Home Plate on that region, in early 2006.

Rover tracks from driving by Spirit are visible on Home plate in the center and right of the image. These were made during Spirit's second exploration on top of the plateau, which began when Spirit climbed onto the southern edge of Home Plate in September, 2007.

In the center foreground, the turret of tools at the end of Spirit's robotic arm appears in duplicate because the arm was repositioned between the days when the images making up that part of the mosaic were taken.

On the horizon, the highest point is 'McCool Hill.' This is one of the seven larger hills in the Columbia Hills range. Home Plate is in the inner basin of the range, between McCool Hill to the south and 'Husband Hill' to the north. To the right of McCool Hill, in the center of the image and closer to Home Plate, is a smaller hill capped with a light-toned outcrop. This hill is called 'Von Braun,' and it is a possible destination the rover team has discussed for the next season of driving by Spirit, after the solar energy level increases in the Martian spring. The flat horizon in the right-hand portion of the panorama is the basaltic plain onto which Spirit landed on Jan. 4, 2004.

This is an approximate true-color, red-green-blue composite panorama generated from images taken through the Pancam's 750-nanometer, 530-nanometer and 430-nanometer filters. This 'natural color' view is the rover team's best estimate of what the scene would look like if we were there and able to see it with our own eyes.

Ongoing Search for Metal Line Emission in Intermediate and High Velocity Clouds with WHAM

NASA Astrophysics Data System (ADS)

Barger, K. A.; Haffner, L. M.; Madsen, G. J.; Hill, A. S.; Wakker, B. P.

2010-01-01

We present new observations of the ionized gas in Complexes A, K, and L obtained with the Wisconsin H-Alpha Mapper (WHAM). To date, there have been only a limited number of studies of the ionized components of intermediate and high velocity clouds. Investigating their emission provides a rare probe of the physical conditions of the clouds and the halo they are embedded within. These types of measurements will help guide discussion of the origin and evolution of these neutral halo structures. Here we follow up on the H-alpha maps we have presented elsewhere with deeper observations in H-alpha, [S II], [N II], and [O I]. Distance constraints from absorption studies place this gas in the mid to lower Galactic halo. Complex A has been constrained to a distance of 8-10 kpc (Wakker et al. 2008); Complex K has an upper limit of 6.8 kpc; and Complex L at a distance of 8-15 kpc (Wakker 2000). Some halo gas structures have clear metal line emission (e.g., Smith Cloud; Hill et al. 2009 and this meeting); however, the lack of [S II] emission toward Complex C combined with absorption-line observations demonstrates that it has very low metallically (Wakker, et al. 1999). Such discoveries reveal ongoing gas replenishment of the evolving Milky Way. Here, we find a similar lack of emission toward the high-velocity Complex A. In particular, the cores of its cloud components designated III and IV show no evidence for metal line emission in our new observations, which places new constraints on the metallically of this complex. These observations were taken with WHAM at Kitt Peak, and we thank the excellent, decade-long support from its staff. WHAM operations are supported through NSF award AST-0607512.

Weather Features Associated with Aircraft Icing Conditions: A Case Study

PubMed Central

Fernández-González, Sergio; Sánchez, José Luis; Gascón, Estíbaliz; López, Laura; García-Ortega, Eduardo; Merino, Andrés

2014-01-01

In the context of aviation weather hazards, the study of aircraft icing is very important because of several accidents attributed to it over recent decades. On February 1, 2012, an unusual meteorological situation caused severe icing of a C-212-200, an aircraft used during winter 2011-2012 to study winter cloud systems in the Guadarrama Mountains of the central Iberian Peninsula. Observations in this case were from a MP-3000A microwave radiometric profiler, which acquired atmospheric temperature and humidity profiles continuously every 2.5 minutes. A Cloud Aerosol and Precipitation Spectrometer (CAPS) was also used to study cloud hydrometeors. Finally, ice nuclei concentration was measured in an isothermal cloud chamber, with the goal of calculating concentrations in the study area. Synoptic and mesoscale meteorological conditions were analysed using the Weather Research and Forecasting (WRF) model. It was demonstrated that topography influenced generation of a mesolow and gravity waves on the lee side of the orographic barrier, in the region where the aircraft experienced icing. Other factors such as moisture, wind direction, temperature, atmospheric stability, and wind shear were decisive in the appearance of icing. This study indicates that icing conditions may arise locally, even when the synoptic situation does not indicate any risk. PMID:24701152

Southern Clouds

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Context image for PIA03026 Southern Clouds

This image shows a system of clouds just off the margin of the South Polar cap. Taken during the summer season, these clouds contain both water-ice and dust.

Image information: VIS instrument. Latitude 80.2S, Longitude 57.6E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Effects of turbulence on warm clouds and precipitation with various aerosol concentrations

NASA Astrophysics Data System (ADS)

Lee, Hyunho; Baik, Jong-Jin; Han, Ji-Young

2015-02-01

This study investigates the effects of turbulence-induced collision enhancement (TICE) on warm clouds and precipitation by changing the cloud condensation nuclei (CCN) number concentration using a two-dimensional dynamic model with bin microphysics. TICE is determined according to the Taylor microscale Reynolds number and the turbulent dissipation rate. The thermodynamic sounding used in this study is characterized by a warm and humid atmosphere with a capping inversion layer, which is suitable for simulating warm clouds. For all CCN concentrations, TICE slightly reduces the liquid water path during the early stage of cloud development and accelerates the onset of surface precipitation. However, changes in the rainwater path and in the amount of surface precipitation that are caused by TICE depend on the CCN concentrations. For high CCN concentrations, the mean cloud drop number concentration (CDNC) decreases and the mean effective radius increases due to TICE. These changes cause an increase in the amount of surface precipitation. However, for low CCN concentrations, changes in the mean CDNC and in the mean effective radius induced by TICE are small and the amount of surface precipitation decreases slightly due to TICE. A decrease in condensation due to the accelerated coalescence between droplets explains the surface precipitation decrease. In addition, an increase in the CCN concentration can lead to an increase in the amount of surface precipitation, and the relationship between the CCN concentration and the amount of surface precipitation is affected by TICE. It is shown that these results depend on the atmospheric relative humidity.

Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qing; Gustafson, William I.; Fast, Jerome D.

2011-12-02

In the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model, we have coupled the Morrison double-moment microphysics scheme with interactive aerosols so that full two-way aerosol-cloud interactions are included in simulations. We have used this new WRF-Chem functionality in a study focused on assessing predictions of aerosols, marine stratocumulus clouds, and their interactions over the Southeast Pacific using measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals. This study also serves as a detailed analysis of our WRF-Chem simulations contributed to the VOCALS model Assessment (VOCA) project. The WRF-Chem 31-day (October 15-November 16,more » 2008) simulation with aerosol-cloud interactions (AERO hereafter) is also compared to a simulation (MET hereafter) with fixed cloud droplet number concentrations assumed by the default in Morrison microphysics scheme with no interactive aerosols. The well-predicted aerosol properties such as number, mass composition, and optical depth lead to significant improvements in many features of the predicted stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness, and cloud macrostructure such as cloud depth and cloud base height. These improvements in addition to the aerosol direct and semi-direct effects, in turn, feed back to the prediction of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengths temperature and humidity gradients within capping inversion layer and lowers the MBL depth by 150 m from that of the MET simulation. Mean top-of-the-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with observations in AERO, compared to the MET simulation. Nevertheless, biases in some of the simulated meteorological quantities (e.g., MBL temperature and humidity over the remote ocean) and aerosol quantities (e.g., overestimations of supermicron sea salt mass) might affect simulated stratocumulus and energy fluxes over the SEP, and require further investigations. Although not perfect, the overall performance of the regional model in simulating mesoscale aerosol-cloud interactions is encouraging and suggests that the inclusion of spatially varying aerosol characteristics is important when simulating marine stratocumulus over the southeastern Pacific.« less

Studying the influence of temperature and pressure on microphysical properties of mixed-phase clouds using airborne measurements

NASA Astrophysics Data System (ADS)

Andreea, Boscornea; Sabina, Stefan; Sorin-Nicolae, Vajaiac; Mihai, Cimpuieru

2015-04-01

One cloud type for which the formation and evolution process is not well-understood is the mixed-phase type. In general mixed-phase clouds consist of liquid droplets and ice crystals. The temperature interval within both liquid droplets and ice crystals can potentially coexist is limited to 0 °C and - 40 °C. Mixed-phase clouds account for 20% to 30% of the global cloud coverage. The need to understand the microphysical characteristics of mixed-phase clouds to improve numerical forecast modeling and radiative transfer calculation is of major interest in the atmospheric community. In the past, studies of cloud phase composition have been significantly limited by a lack of aircraft instruments capable of discriminating between the ice and liquid phase for a wide range of particle sizes. Presently, in situ airborne measurements provide the most accurate information about cloud microphysical characteristics. This information can be used for verification of both numerical models and cloud remote-sensing techniques. The knowledge of the temperature and pressure variation during the airborne measurements is crucial in order to understand their influence on the cloud dynamics and also their role in the cloud formation processes like accretion and coalescence. Therefore, in this paper is presented a comprehensive study of cloud microphysical properties in mixed-phase clouds in focus of the influence of temperature and pressure variation on both, cloud dynamics and the cloud formation processes, using measurements performed with the ATMOSLAB - Airborne Laboratory for Environmental Atmospheric Research in property of the National Institute for Aerospace Research "Elie Carafoli" (INCAS). The airborne laboratory equipped for special research missions is based on a Hawker Beechcraft - King Air C90 GTx aircraft and is equipped with a sensors system CAPS - Cloud, Aerosol and Precipitation Spectrometer (30 bins, 0.51-50 µm) and a HAWKEYE cloud probe. The analyzed data in this work is acquired during 2 flight hours on the 23th of October 2014 in mixed clouds formations over Romania ( Craiova, Lat 44°19', Lon 23°48' ). The temperature variation during the cloud sounding was between -14 °C and -2 °C, with a maximum altitude in the cloud of 4863 m and a minimum altitude of 3353 m. In total 6 horizontal lines of 10 minutes each where performed recording ice crystal number concentrations (using the CIP - Cloud Imaging Probe) between 10 to 20 particles/cm3 outside the cloud layer and over 100 particles/cm3 inside the cloud layer and a number concentration of small droplets, aerosol and small ice crystals (using the CAS - Cloud Aerosol Spectrometer) between 150 particles/cm3 outside the cloud layer and 1600 particles/cm3 inside the cloud layer, this values confirms also the presence of IN (ice nuclei) in the atmosphere between the cloud layers. The results in respect with size distribution of cloud's particles and LWC show to be controlled by the temperature and pressure variations.

Ash and Steam, Soufriere Hills Volcano, Monserrat

NASA Technical Reports Server (NTRS)

2002-01-01

International Space Station crew members are regularly alerted to dynamic events on the Earth's surface. On request from scientists on the ground, the ISS crew observed and recorded activity from the summit of Soufriere Hills on March 20, 2002. These two images provide a context view of the island (bottom) and a detailed view of the summit plume (top). When the images were taken, the eastern side of the summit region experienced continued lava growth, and reports posted on the Smithsonian Institution's Weekly Volcanic Activity Report indicate that 'large (50-70 m high), fast-growing, spines developed on the dome's summit. These spines periodically collapsed, producing pyroclastic flows down the volcano's east flank that sometimes reached the Tar River fan. Small ash clouds produced from these events reached roughly 1 km above the volcano and drifted westward over Plymouth and Richmond Hill. Ash predominately fell into the sea. Sulfur dioxide emission rates remained high. Theodolite measurements of the dome taken on March 20 yielded a dome height of 1,039 m.' Other photographs by astronauts of Montserrat have been posted on the Earth Observatory: digital photograph number ISS002-E-9309, taken on July 9, 2001; and a recolored and reprojected version of the same image. Digital photograph numbers ISS004-E-8972 and 8973 were taken 20 March, 2002 from Space Station Alpha and were provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

Chiral recognition of phenylglycinol enantiomers based on N-acetyl-L-cysteine capped CdTe quantum dots in the presence of Ag+

NASA Astrophysics Data System (ADS)

Guo, Yuan; Zeng, Xiaoqing; Yuan, Haiyan; Huang, Yunmei; Zhao, Yanmei; Wu, Huan; Yang, Jidong

2017-08-01

In this study, a novel method for chiral recognition of phenylglycinol (PG) enantiomers was proposed. Firstly, water-soluble N-acetyl-L-cysteine (NALC)-capped CdTe quantum dots (QDs) were synthesized and experiment showed that the fluorescence intensity of the reaction system slightly enhancement when added PG enantiomers to NALC-capped CdTe quantum dots (QDs), but the R-PG and S-PG could not be distinguished. Secondly, when there was Ag+ presence in the reaction system, the experiment result was extremely interesting, the PG enantiomers cloud make NALC-capped CdTe QDs produce different fluorescence signal, in which the fluorescence of S-PG + Ag+ + NALC-CdTe system was significantly enhanced, and the fluorescence of R-PG + Ag+ + NALC-CdTe system was markedly decreased. Thirdly, all the enhanced and decreased of the fluorescence intensity were directly proportional to the concentration of R-PG and S-PG in the linearly range 10- 5-10- 7 mol·L- 1, respectively. So, the new method for simultaneous determination of the PG enantiomers was built too. The experiment result of the method was satisfactory with the detection limit of PG can reached 10- 7 mol·L- 1 and the related coefficient of S-PG and R-PG are 0.995 and 0.980, respectively. The method was highly sensitive, selective and had wider detection range compared with other methods.

The Two Moons of Mars As Seen from 'Husband Hill'

NASA Technical Reports Server (NTRS)

2005-01-01

Taking advantage of extra solar energy collected during the day, NASA's Mars Exloration Rover Spirit settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. Spirit took this succession of images at 150-second intervals from a perch atop 'Husband Hill' in Gusev Crater on martian day, or sol, 594 (Sept. 4, 2005), as the faster-moving martian moon Phobos was passing Deimos in the night sky. Phobos is the brighter object on the left and Deimos is the dimmer object on the right. The bright star Aldebaran and some other stars in the constellation Taurus are visible as star trails. Most of the other streaks in the image are the result of cosmic rays lighting up random groups of pixels in the camera.

Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this c omposite with its panoramic camera using the camera's broadband filter, which was designed specifically for acquiring images under low-light conditions.

Environmental Characteristics of Convective Systems During TRMM-LBA

NASA Technical Reports Server (NTRS)

Halverson, Jeffrey B.; Rickenbach, Thomas; Roy, Biswadev; Pierce, Harold; Williams, Earle; Einaudi, Franco (Technical Monitor)

2001-01-01

In this paper, data collected from 51 days of continual upper atmospheric soundings and TOGA radar at ABRACOS Hill during the TRMM-LBA experiment are used to describe the mean thermodynamic and kinematic airmass properties of wet season convection over Rondonia, Brazil. Distinct multi-day easterly and westerly lower tropospheric wind regimes occurred during the campaign with contrasting airmass characteristics. Westerly wind periods featured modest CAPE (1000 J/kg), moist conditions (>90% RH) extending through 700 mb and shallow (900 mb) speed shear on the order of 10(exp -4)/s. This combination of characteristics promoted convective systems that featured a relatively large fraction of stratiform rainfall and weak convection nearly devoid of lightning. The environment is very similar to the general airmass conditions experienced during the Darwin, Australia monsoon convective regime. In contrast, easterly regime convective systems were more strongly electrified and featured larger convective rain rates and reduced stratiform rainfall fraction. These systems formed in an environment with significantly larger CAPE (1500 J/kg), drier lower and middle level humidities (< 80% RH) and a wind shear layer that was both stronger (10(exp -3)/s) and deeper (700 mb). The larger CAPE resulted from strong insolation under relatively cloud-free skies (owing to reduced column humidity) and was also weakly capped in the lowest 1-2 km, thus contributing to a more explosive growth of convection. The time series of low- and mid-level averaged humidity exhibited marked variability between westerly and easterly regimes and was characterized by low frequency (i.e., multi-day to weekly) oscillations. The synoptic scale origins of these moisture fluctuations are examined, which include the effects of variable low-level airmass trajectories and upper-level, westward migrating cyclonic vortices. The results reported herein provide an environmental context for ongoing dual Doppler analyses and numerical modeling case studies of individual TRMM-LBA convective systems.

Using Satellite Observations to Evaluate the AeroCOM Volcanic Emissions Inventory and the Dispersal of Volcanic SO2 Clouds in MERRA

NASA Technical Reports Server (NTRS)

Hughes, Eric J.; Krotkov, Nickolay; da Silva, Arlindo; Colarco, Peter

2015-01-01

Simulation of volcanic emissions in climate models requires information that describes the eruption of the emissions into the atmosphere. While the total amount of gases and aerosols released from a volcanic eruption can be readily estimated from satellite observations, information about the source parameters, like injection altitude, eruption time and duration, is often not directly known. The AeroCOM volcanic emissions inventory provides estimates of eruption source parameters and has been used to initialize volcanic emissions in reanalysis projects, like MERRA. The AeroCOM volcanic emission inventory provides an eruptions daily SO2 flux and plume top altitude, yet an eruption can be very short lived, lasting only a few hours, and emit clouds at multiple altitudes. Case studies comparing the satellite observed dispersal of volcanic SO2 clouds to simulations in MERRA have shown mixed results. Some cases show good agreement with observations Okmok (2008), while for other eruptions the observed initial SO2 mass is half of that in the simulations, Sierra Negra (2005). In other cases, the initial SO2 amount agrees with the observations but shows very different dispersal rates, Soufriere Hills (2006). In the aviation hazards community, deriving accurate source terms is crucial for monitoring and short-term forecasting (24-h) of volcanic clouds. Back trajectory methods have been developed which use satellite observations and transport models to estimate the injection altitude, eruption time, and eruption duration of observed volcanic clouds. These methods can provide eruption timing estimates on a 2-hour temporal resolution and estimate the altitude and depth of a volcanic cloud. To better understand the differences between MERRA simulations and volcanic SO2 observations, back trajectory methods are used to estimate the source term parameters for a few volcanic eruptions and compared to their corresponding entry in the AeroCOM volcanic emission inventory. The nature of these mixed results is discussed with respect to the source term estimates.

Chemical Impact of Solar Energetic Particle Event From The Young Sun: Implications for the Origin of Prebiotic Chemistry and the Fain Young Sun Paradox

NASA Astrophysics Data System (ADS)

Airapetian, V.; Gronoff, G.; Hébrard, E.; Danchi, W.

2015-12-01

Understanding how the simple molecules present on the early Earth and possibly Mars may have set a path for complex biological molecules, the building blocks of life, represents one of greatest unsolved questions. Here we present a new model of the rise of the abiotic nitrogen fixation and associated pre-biotic chemistry in the early Earth and Mars atmosphere mediated by solar eruptive events. Our physical models of interaction of magnetic clouds ejected from the young Sun with magnetospheres of the early Earth show significant perturbations of geomagnetic fields that produce extended polar caps. These polar caps provide pathways for energetic particles associated with magnetic clouds to penetrate into the nitrogen-rich weakly reducing atmosphere and initiate the reactive chemistry by breaking molecular nitrogen, carbon dioxide, methane and producing hydrogen cyanide, the essential compound for life. The model also shows that contrary to the current models of warming of early Earth and Mars, major atmospheric constituents, CO2 and CH4 will be destroyed due to collisional dissociation with energetic particles. Instead, efficient formation of the potent greenhouse gas, nitrous oxide, as a by-product of these processes is expected. This mechanism can consistently explain the Faint Young Sun's paradox for the early atmospheres of Earth and Mars. Our new model provides insight into how life may have initiated on Earth and Mars and how to search for the spectral signatures on planets "pregnant" with the potential for life.

Mars Atmospheric CO2 Condensation Above the North and South Poles as Revealed by Radio Occultation, Climate Sounder, and Laser Ranging Observations

NASA Technical Reports Server (NTRS)

Hu, Renyu; Cahoy, Kerri; Zuber, Maria T.

2012-01-01

We study the condensation of CO2 in Mars atmosphere using temperature profilesretrieved from radio occultation measurements from Mars Global Surveyor (MGS) as wellas the climate sounding instrument onboard the Mars Reconnaissance Orbiter (MRO),and detection of reflective clouds by the MGS Mars Orbiter Laser Altimeter (MOLA). Wefind 11 events in 1999 where MGS temperature profiles indicate CO2 condensation andMOLA simultaneously detects reflective clouds. We thus provide causal evidence thatMOLA non-ground returns are associated with CO2 condensation, which strongly indicatestheir nature being CO2 clouds. The MGS and MRO temperature profiles together revealthe seasonal expansion and shrinking of the area and the vertical extent of atmosphericsaturation. The occurrence rate of atmospheric saturation is maximized at high latitudes inthe middle of winter. The atmospheric saturation in the northern polar region exhibits moreintense seasonal variation than in the southern polar region. In particular, a shrinking ofsaturation area and thickness from LS 270 to 300 in 2007 is found; this is probablyrelated to a planet-encircling dust storm. Furthermore, we integrate the condensation areaand the condensation occurrence rate to estimate cumulative masses of CO2 condensatesdeposited onto the northern and southern seasonal polar caps. The precipitation flux isapproximated by the particle settling flux which is estimated using the impulse responses ofMOLA filter channels. With our approach, the total atmospheric condensation mass canbe estimated from these observational data sets with average particle size as the onlyfree parameter. By comparison with the seasonal polar cap masses inferred from thetime-varying gravity of Mars, our estimates indicate that the average condensate particleradius is 822 mm in the northern hemisphere and 413 mm in the southern hemisphere.Our multi-instrument data analysis provides new constraints on modeling the global climateof Mars.

Mars atmospheric CO2 condensation above the north and south poles as revealed by radio occultation, climate sounder, and laser ranging observations

NASA Astrophysics Data System (ADS)

Hu, Renyu; Cahoy, Kerri; Zuber, Maria T.

2012-07-01

We study the condensation of CO2 in Mars' atmosphere using temperature profiles retrieved from radio occultation measurements from Mars Global Surveyor (MGS) as well as the climate sounding instrument onboard the Mars Reconnaissance Orbiter (MRO), and detection of reflective clouds by the MGS Mars Orbiter Laser Altimeter (MOLA). We find 11 events in 1999 where MGS temperature profiles indicate CO2 condensation and MOLA simultaneously detects reflective clouds. We thus provide causal evidence that MOLA non-ground returns are associated with CO2 condensation, which strongly indicates their nature being CO2 clouds. The MGS and MRO temperature profiles together reveal the seasonal expansion and shrinking of the area and the vertical extent of atmospheric saturation. The occurrence rate of atmospheric saturation is maximized at high latitudes in the middle of winter. The atmospheric saturation in the northern polar region exhibits more intense seasonal variation than in the southern polar region. In particular, a shrinking of saturation area and thickness from LS ˜ 270° to ˜300° in 2007 is found; this is probably related to a planet-encircling dust storm. Furthermore, we integrate the condensation area and the condensation occurrence rate to estimate cumulative masses of CO2 condensates deposited onto the northern and southern seasonal polar caps. The precipitation flux is approximated by the particle settling flux which is estimated using the impulse responses of MOLA filter channels. With our approach, the total atmospheric condensation mass can be estimated from these observational data sets with average particle size as the only free parameter. By comparison with the seasonal polar cap masses inferred from the time-varying gravity of Mars, our estimates indicate that the average condensate particle radius is 8-22 μm in the northern hemisphere and 4-13 μm in the southern hemisphere. Our multi-instrument data analysis provides new constraints on modeling the global climate of Mars.

The morphodynamics and internal structure of intertidal fine-gravel dunes: Hills Flats, Severn Estuary, UK

NASA Astrophysics Data System (ADS)

Carling, P. A.; Radecki-Pawlik, A.; Williams, J. J.; Rumble, B.; Meshkova, L.; Bell, P.; Breakspear, R.

2006-01-01

In the macrotidal Severn estuary, UK, the dynamics of intertidal fine-gravel dunes were investigated. These dunes are migrating across a bedrock platform. Systematic observations were made of hydraulic climate, geometry, migration rates and internal sedimentary structures of the dunes. During spring tides, the ebb flow is dominant, dunes grow in height and have ebb orientated geometry with bedrock floors in the troughs. During neap tides, a weak flood flow may dominate. Dunes then are flood orientated or symmetrical. Neap dune heights decrease and the eroded sediment is stored in the dune troughs where the bedrock becomes blanketed by muddy gravel. During spring tides, instantaneous bed shear stresses reach 8 N m - 2 , sufficient to disrupt a 9 mm-gravel armour layer. However, a sustained bed shear stress of 4 N m - 2 is required to initiate dune migration at which time the critical depth-mean velocity is 1 m s - 1 . Ebb and flood inequalities in the bed shear stress explain the changes in dune asymmetry and internal structures. During flood tides, the crests of the dunes reverse such that very mobile sedimentary 'caps' overlie a more stable dune 'core'. Because ebb tides dominate, internal structures of the caps often are characterised by ebb orientated steep open-work foresets developed by strong tidal currents and some lower angle crossbeds deposited as weaker currents degrade foresets. The foresets forming the caps may be grouped into cosets (tidal bundles) and are separated from mud-infused cores of crossbeds that lie below, by reactivation and erosion surfaces blanketed by discontinuous mud drapes. The cores often exhibit distinctive muddy toe sets that define the spacing of tidal cosets.

Design of relative motion and attitude profiles for three-dimensional resident space object imaging with a laser rangefinder

NASA Astrophysics Data System (ADS)

Nayak, M.; Beck, J.; Udrea, B.

This paper focuses on the aerospace application of a single beam laser rangefinder (LRF) for 3D imaging, shape detection, and reconstruction in the context of a space-based space situational awareness (SSA) mission scenario. The primary limitation to 3D imaging from LRF point clouds is the one-dimensional nature of the single beam measurements. A method that combines relative orbital motion and scanning attitude motion to generate point clouds has been developed and the design and characterization of multiple relative motion and attitude maneuver profiles are presented. The target resident space object (RSO) has the shape of a generic telecommunications satellite. The shape and attitude of the RSO are unknown to the chaser satellite however, it is assumed that the RSO is un-cooperative and has fixed inertial pointing. All sensors in the metrology chain are assumed ideal. A previous study by the authors used pure Keplerian motion to perform a similar 3D imaging mission at an asteroid. A new baseline for proximity operations maneuvers for LRF scanning, based on a waypoint adaptation of the Hill-Clohessy-Wiltshire (HCW) equations is examined. Propellant expenditure for each waypoint profile is discussed and combinations of relative motion and attitude maneuvers that minimize the propellant used to achieve a minimum required point cloud density are studied. Both LRF strike-point coverage and point cloud density are maximized; the capability for 3D shape registration and reconstruction from point clouds generated with a single beam LRF without catalog comparison is proven. Next, a method of using edge detection algorithms to process a point cloud into a 3D modeled image containing reconstructed shapes is presented. Weighted accuracy of edge reconstruction with respect to the true model is used to calculate a qualitative “ metric” that evaluates effectiveness of coverage. Both edge recognition algorithms and the metric are independent of point cloud densit- , therefore they are utilized to compare the quality of point clouds generated by various attitude and waypoint command profiles. The RSO model incorporates diverse irregular protruding shapes, such as open sensor covers, instrument pods and solar arrays, to test the limits of the algorithms. This analysis is used to mathematically prove that point clouds generated by a single-beam LRF can achieve sufficient edge recognition accuracy for SSA applications, with meaningful shape information extractable even from sparse point clouds. For all command profiles, reconstruction of RSO shapes from the point clouds generated with the proposed method are compared to the truth model and conclusions are drawn regarding their fidelity.

The UAE Rainfall Enhancement Assessment Program: Implications of Thermodynamic Profiles on the Development of Precipitation in Convective Clouds over the Oman Mountains

NASA Astrophysics Data System (ADS)

Breed, D.; Bruintjes, R.; Jensen, T.; Salazar, V.; Fowler, T.

2005-12-01

During the winter and summer seasons of 2001 and 2002, data were collected to assess the efficacy of cloud seeding to enhance precipitation in the United Arab Emirates (UAE). The results of the feasibility study concluded: 1) that winter clouds in the UAE rarely produced conditions amenable to hygroscopic cloud seeding; 2) that summer convective clouds developed often enough, particularly over the Oman Mountains (e.g., the Hajar Mountains along the eastern UAE border and into Oman) to justify a randomized seeding experiment; 3) that collecting quantitative radar observations continues to be a complex but essential part of evaluating a cloud seeding experiment; 4) that successful flight operations would require solving several logistical issues; and 5) that several scientific questions would need to be studied in order to fully evaluate the efficacy and feasibility of hygroscopic cloud seeding, including cloud physical responses, radar-derived rainfall estimates as related to rainfall at the ground, and hydrological impacts. Based on these results, the UAE program proceeded through the design and implemention of a randomized hygroscopic cloud seeding experiment during the summer seasons to statistically quantify the potential for cloud seeding to enhance rainfall, specifically over the UAE and Oman Mountains, while collecting concurrent and separate physical measurements to support the statistical results and provide substantiation for the physical hypothesis. The randomized seeding experiment was carried out over the summers of 2003 and 2004, and a total of 134 cases were treated over the two summer seasons, of which 96 met the analysis criteria established in the experimental design of the program. The statistical evaluation of these cases yielded largely inconclusive results. Evidence will show that the thermodynamic profile had a large influence on storm characteristics and on precipitation development. This in turn provided a confounding factor in the conduct of the seeding experiment, particularly in the lateness of treatment in the storm cycle. The prevalence of capping inversions and the sensitivity of clouds to the level of the inversions as well as to wind shear will be shown using several data sets (soundings, aircraft, radar, numerical models). Concurrent physical measurements with the randomized experiment provided new insights into the physical processes of precipitation that developed in summertime convective clouds over the UAE that in turn helped in the interpretation of the statistical results.

Octopus: A Design Methodology for Motion Capture Wearables

PubMed Central

2017-01-01

Human motion capture (MoCap) is widely recognised for its usefulness and application in different fields, such as health, sports, and leisure; therefore, its inclusion in current wearables (MoCap-wearables) is increasing, and it may be very useful in a context of intelligent objects interconnected with each other and to the cloud in the Internet of Things (IoT). However, capturing human movement adequately requires addressing difficult-to-satisfy requirements, which means that the applications that are possible with this technology are held back by a series of accessibility barriers, some technological and some regarding usability. To overcome these barriers and generate products with greater wearability that are more efficient and accessible, factors are compiled through a review of publications and market research. The result of this analysis is a design methodology called Octopus, which ranks these factors and schematises them. Octopus provides a tool that can help define design requirements for multidisciplinary teams, generating a common framework and offering a new method of communication between them. PMID:28809786

Octopus: A Design Methodology for Motion Capture Wearables.

PubMed

Marin, Javier; Blanco, Teresa; Marin, Jose J

2017-08-15

Human motion capture (MoCap) is widely recognised for its usefulness and application in different fields, such as health, sports, and leisure; therefore, its inclusion in current wearables (MoCap-wearables) is increasing, and it may be very useful in a context of intelligent objects interconnected with each other and to the cloud in the Internet of Things (IoT). However, capturing human movement adequately requires addressing difficult-to-satisfy requirements, which means that the applications that are possible with this technology are held back by a series of accessibility barriers, some technological and some regarding usability. To overcome these barriers and generate products with greater wearability that are more efficient and accessible, factors are compiled through a review of publications and market research. The result of this analysis is a design methodology called Octopus, which ranks these factors and schematises them. Octopus provides a tool that can help define design requirements for multidisciplinary teams, generating a common framework and offering a new method of communication between them.

The opposition of Mars, 1999

NASA Astrophysics Data System (ADS)

McKim, R. J.

2007-12-01

The 1999 martian apparition was followed by BAA members while Mars Global Surveyor was monitoring the planet from martian orbit. The planet's surface showed little change from 1997, indicating the absence of any great dust storm since solar conjunction. The long period of telescopic coverage enabled us to conclude that neither was there any planet-encircling storm in the southern martian spring or summer in 1999-2000. Three small telescopic storms were followed along the Valles Marineris, and two were seen at the edge of the summer N. polar cap. Dust storms commencing at the historically rarely-active Margaritifer Sinus emergence site (MGS data) point to ongoing changes in the fallout pattern of atmospheric dust. White cloud activity was high before and around opposition time - in northern midsummer - with morning and evening limb hazes, the equatorial cloud band (ECB) and orographic clouds. The ECB 'season' was identical to 1997, pointing to an equally low level of atmospheric dust-loading. Comparison with historical records suggests that the seasonal 'wave of darkening' may be partly attributable to the annual disappearance of the ECB. This report covers the period 1998 September 12 (Ls = 28°) to 2000 March 13 (Ls = 318°)

Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx

NASA Astrophysics Data System (ADS)

Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

2011-09-01

Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. The BL had a depth of 1140 ± 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and meso-scale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October-4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cloud LWP relationship reveals that during the typical well-mixed BL days the cloud LWP increased with the CCN concentrations. On the other hand, meteorological factors and the decoupling processes have large influences on the cloud LWP variation as well.

Research Opportunities at Storm Peak Laboratory

NASA Astrophysics Data System (ADS)

Hallar, A. G.; McCubbin, I. B.

2006-12-01

The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation of 3210 m MSL (Borys and Wetzel, 1997). SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. The ridge-top location produces almost daily transition from free tropospheric to boundary layer air which occurs near midday in both summer and winter seasons. Long-term observations at SPL document the role of orographically induced mixing and convection on vertical pollutant transport and dispersion. During winter, SPL is above cloud base 25% of the time, providing a unique capability for studying aerosol-cloud interactions (Borys and Wetzel, 1997). A comprehensive set of continuous aerosol measurements was initiated at SPL in 2002. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a cold room for precipitation and cloud rime ice sample handling and ice crystal microphotography, a 150 m2 roof deck area for outside sampling equipment, a full kitchen and two bunk rooms with sleeping space for nine persons. The laboratory is currently well equipped for aerosol and cloud measurements. Particles are sampled from an insulated, 15 cm diameter manifold within approximately 1 m of its horizontal entry point through an outside wall. The 4 m high vertical section outside the building is capped with an inverted can to exclude large particles.

Near-field monitoring of the Eyjafjallajökull eruption cloud

NASA Astrophysics Data System (ADS)

Bjornsson, H.; Pedersen, G. N.; Arason, P.; Karlsdottir, S.; Vogfjord, K. S.; Thorsteinsson, H.; Palmason, B.; Sigurdsson, A.

2010-12-01

When the ice capped Eyjafjallajökull volcano erupted in April 2010 the Icelandic Meteorological Office (IMO) employed range of observation systems to monitor the eruption cloud and the progress of the eruption. The main tool for monitoring the volcanic cloud was a C-band weather radar located at Keflavik international airport, about 150 km from the volcano. Radar monitoring was supported by visual observations, on-site and from a network of web-cameras. Airborne observations allowed for detailed examination of the plume, and pilot reports proved to be an extremely useful aid in verifying the radar data. Furthermore, data from lightning sensors and radiosondes was used to supplement information on plume height. Satellite images, from several frequency bands and both polar as well as geostationary satellites were used to track the orientation of the eruption cloud, and brightness temperature difference was used to estimate far field ash dispersal. Ash fall monitoring and meteorological observations supplemented with atmospheric reanalysis and wind forecasts were used to track local ash dispersal. Information from these data sources was combined with geophysical and hydrological measurements (seismic, GPS, strain and river flow gauges) made by the IMO, the Earth Institute of the University of Iceland and other institutions. The data generated by these different observation types gives a consistent picture of the progression of the eruption and reveals interesting connections. For example, volcanic tremors tended to be inversly related to the eruption cloud height, increasing tremors were associated lower plume height and reduced eruption strength. Furthermore, the occurrence of lighting seems to be explained by both sufficiently strong plume and cold ambient air. Wind also had a clear effect on the eruption cloud height. In general, simple scaling laws for the relationship between the emission rate of the volcano, and the height of the eruption do not seem to explain all the height variations in the eruption cloud.

Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang Q.; Lee Y.; Gustafson Jr., W. I.

2011-12-02

This study assesses the ability of the recent chemistry version (v3.3) of the Weather Research and Forecasting (WRF-Chem) model to simulate boundary layer structure, aerosols, stratocumulus clouds, and energy fluxes over the Southeast Pacific Ocean. Measurements from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) and satellite retrievals (i.e., products from the MODerate resolution Imaging Spectroradiometer (MODIS), Clouds and Earth's Radiant Energy System (CERES), and GOES-10) are used for this assessment. The Morrison double-moment microphysics scheme is newly coupled with interactive aerosols in the model. The 31-day (15 October-16 November 2008) WRF-Chem simulation with aerosol-cloud interactions (AERO hereafter) is also comparedmore » to a simulation (MET hereafter) with fixed cloud droplet number concentrations in the microphysics scheme and simplified cloud and aerosol treatments in the radiation scheme. The well-simulated aerosol quantities (aerosol number, mass composition and optical properties), and the inclusion of full aerosol-cloud couplings lead to significant improvements in many features of the simulated stratocumulus clouds: cloud optical properties and microphysical properties such as cloud top effective radius, cloud water path, and cloud optical thickness. In addition to accounting for the aerosol direct and semi-direct effects, these improvements feed back to the simulation of boundary-layer characteristics and energy budgets. Particularly, inclusion of interactive aerosols in AERO strengthens the temperature and humidity gradients within the capping inversion layer and lowers the marine boundary layer (MBL) depth by 130 m from that of the MET simulation. These differences are associated with weaker entrainment and stronger mean subsidence at the top of the MBL in AERO. Mean top-of-atmosphere outgoing shortwave fluxes, surface latent heat, and surface downwelling longwave fluxes are in better agreement with observations in AERO, compared to the MET simulation. Nevertheless, biases in some of the simulated meteorological quantities (e.g., MBL temperature and humidity) and aerosol quantities (e.g., underestimations of accumulation mode aerosol number) might affect simulated stratocumulus and energy fluxes over the Southeastern Pacific, and require further investigation. The well-simulated timing and outflow patterns of polluted and clean episodes demonstrate the model's ability to capture daily/synoptic scale variations of aerosol and cloud properties, and suggest that the model is suitable for studying atmospheric processes associated with pollution outflow over the ocean. The overall performance of the regional model in simulating mesoscale clouds and boundary layer properties is encouraging and suggests that reproducing gradients of aerosol and cloud droplet concentrations and coupling cloud-aerosol-radiation processes are important when simulating marine stratocumulus over the Southeast Pacific.« less

Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium).

NASA Astrophysics Data System (ADS)

di Diodato, A.; de Leonibus, L.; Zauli, F.; Biron, D.; Melfi, D.

2009-04-01

Operational Estimation of Accumulated Precipitation using Satellite Observation, by Eumetsat Satellite Application facility in Support to Hydrology (H-SAF Consortium). Cap. Attilio DI DIODATO(*), T.Col. Luigi DE LEONIBUS(*), T.Col Francesco ZAULI(*), Cap. Daniele BIRON(*), Ten. Davide Melfi(*) Satellite Application Facilities (SAFs) are specialised development and processing centres of the EUMETSAT Distributed Ground Segment. SAFs process level 1b data from meteorological satellites (geostationary and polar ones) in conjunction with all other relevant sources of data and appropriate models to generate services and level 2 products. Each SAF is a consortium of EUMETSAT European partners lead by a host institute responsible for the management of the complete SAF project. The Meteorological Service of Italian Air Force is the host Institute for the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF). HSAF has the commitment to develop and to provide, operationally after 2010, products regarding precipitation, soil moisture and snow. HSAF is going to provide information on error structure of its products and validation of the products via their impacts into Hydrological models. To that purpose it has been structured a specific subgroups. Accumulated precipitation is computed by temporal integration of the instantaneous rain rate achieved by the blended LEO/MW and GEO/IR precipitation rate products generated by Rapid Update method available every 15 minutes. The algorithm provides four outputs, consisting in accumulated precipitation in 3, 6, 12 and 24 hours, delivered every 3 hours at the synoptic hours. These outputs are our precipitation background fields. Satellite estimates can cover most of the globe, however, they suffer from errors due to lack of a direct relationship between observation parameters and precipitation, the poor sampling and algorithm imperfections. For this reason the 3 hours accumulated precipitation is compared by climatic thresholds got, basically, by the project "Climate Atlas of Europe" led by Meteo France inside the project ECSN (European Climate Support Network) of EUMETNET. To reduce the bias errors introduced by satellite estimates the rain gauge data are used to make an intercalibration with the satellite estimates, using information achieved by GTS network. Precipitation increments are estimated at each observation location from the observation and the interpolated background field. A field of the increments is carried out by standard Kriging method. The final precipitation analysis is achieved by the sum of the increments and the precipitation estimation at each grid points. It is also considered that major error sources in retrieval 15 minutes instantaneous precipitation from cloud top temperature comes from high (cold) non precipitating clouds and the use of same regression coefficients both for warm clouds (stratus) and cold clouds (convective). As that error is intrinsic in the blending technique applied, we are going to improve performances making use of cloud type specified retrievals. To apply such scheme on the products, we apply a discrimination from convective and stratified clouds, then we retrieve precipitation in parallel for the two clouds classes; the two outputs are merged again into one products, solving the double retrieval pixels keeping the convection retrieval. Basic tools for that is the computation of two different lookup tables to associate precipitation at a brightness temperature for the two kinds of cloudiness. The clouds discrimination will be done by the NWC-SAF product named "cloud type" for the stratified clouds and with an application, running operationally at Italian Met Service, named NEFODINA for automatic detection of convective phenomena. Results of studies to improve the accumulated precipitation as well are presented. The studies exploit the potential to use other source of information like quantitative precipitation forecast (QPF) got by numerical weather prediction model to improve the algorithm where the density of ground observations is low, or using it as a background field to generate a precipitation analysis by an optimal interpolation technique. (*) Centro Nazionale Meteorologia e Climatologia Aeronautica - CNMCA

The bioreactivity of the sub-10 μm component of volcanic ash: Soufrière Hills volcano, Montserrat.

PubMed

Jones, Timothy; Bérubé, Kelly

2011-10-30

With the recent eruption of the Icelandic volcano Eyafallajökull and resulting ash cloud over much of Europe there was considerable concern about possible respiratory hazards. Volcanic ash can contain minerals that are known human respiratory health hazards such as cristobalite. Short-term ash exposures can cause skin sores, respiratory and ocular irritations and exacerbation of pre-existing lung conditions such as asthma. Long-term occupational level exposures to crystalline silicon dioxide can cause lung inflammation, oedema, fibrosis and cancer. The potential health effects would be dependent on factors including mineralogy, surface chemistry, size, and levels and duration of exposure. Bulk ash from the Soufrière Hills volcano was sourced and inhalable (<2.5 μm) ash samples prepared and physicochemically characterised. The fine ash samples were tested for bioreactivity by SDS-PAGE which determined the strength of binding between mineral grains and lung proteins. Selected proteins bound tightly to cristobalite, and bound loosely to other ash components. A positive correlation was seen between the amount of SiO(2) in the sample and the strength of the binding. The strength of binding is a function of the mineral's bioreactivity, and therefore, a potential geo-biomarker of respiratory risk. Copyright © 2011 Elsevier B.V. All rights reserved.

In situ fragmentation and rock particle sorting on arid hills

NASA Astrophysics Data System (ADS)

McGrath, Gavan S.; Nie, Zhengyao; Dyskin, Arcady; Byrd, Tia; Jenner, Rowan; Holbeche, Georgina; Hinz, Christoph

2013-03-01

Transport processes are often proposed to explain the sorting of rock particles on arid hillslopes, where mean rock particle size often decreases in the downslope direction. Here we show that in situ fragmentation of rock particles can also produce similar patterns. A total of 93,414 rock particles were digitized from 880 photographs of the surface of three mesa hills in the Great Sandy Desert, Australia. Rock particles were characterized by the projected Feret's diameter and circularity. Distance from the duricrust cap was found to be a more robust explanatory variable for diameter than the local hillslope gradient. Mean diameter decreased exponentially downslope, while the fractional area covered by rock particles decreased linearly. Rock particle diameters were distributed lognormally, with both the location and scale parameters decreasing approximately linearly downslope. Rock particle circularity distributions showed little change; only a slight shift in the mode to more circular particles was noted to occur downslope. A dynamic fragmentation model was used to assess whether in situ weathering alone could reproduce the observed downslope fining of diameters. Modeled and observed size distributions agreed well and both displayed a preferential loss of relatively large rock particles and an apparent approach to a terminal size distribution of the rocks downslope. We show this is consistent with a size effect in material strength, where large rocks are more susceptible to fatigue failure under stress than smaller rocks. In situ fragmentation therefore produces qualitatively similar patterns to those that would be expected to arise from selective transport.

Venus - Lower-level Nightside Clouds As Seen By NIMS

NASA Technical Reports Server (NTRS)

1990-01-01

These images are two versions of a near-infrared map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft as it approached the planet February 10, 1990. Taken from an altitude of about 22,000 miles above the planet, at an infrared wavelength of 2.3 microns (about three times the longest wavelength visible to the human eye) the map shows an area of the turbulent, cloudy middle atmosphere some 30-33 miles above the surface, 6-10 miles below the visible cloudtops. With a spatial resolution of about 13 miles, this is the sharpest image ever obtained of the mid-level clouds of Venus. The image to the left shows the radiant heat from the lower atmosphere (about 400 degrees Fahrenheit) shining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. This cloud layer is at about - 30 degrees Fahrenheit, at a pressure about 1/2 Earth's atmospheric pressure. This high-resolution map covers a 40- degree-wide sector of the Northern Hemisphere. The several irregular vertical stripes are data dropouts. The right image, a modified negative, represents what scientists believe would be the visual appearance of this mid-level cloud deck in daylight, with the clouds reflecting sunlight instead of blocking out infrared from the hot planet and lower atmosphere. Near the equator, the clouds appear fluffy and blocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude. The Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft is a combined mapping (imaging) and spectral instrument. It can sense 408 contiguous wavelengths from 0.7 microns (deep red) to 5.2 microns, and can construct a map or image by mechanical scanning. It can spectroscopically analyze atmospheres and surfaces and construct thermal and chemical maps. Designed and operated by scientists and engineers at the Jet Propulsion Laboratory, NIMS involves 15 scientists in the U.S., England, and France. The Galileo Project is managed for NASA's Office of Space Science and Applications by JPL; its mission is to study the planet Jupiter and its satellites and magnetosphere after multiple gravity-assist flybys at Venus and the Earth.

Venus - Lower-level Clouds As Seen By NIMS

NASA Technical Reports Server (NTRS)

1990-01-01

These images are two versions of a near-infrared map of lower-level clouds on the night side of Venus, obtained by the Near Infrared Mapping Spectrometer aboard the Galileo spacecraft as it approached the planet February 10, 1990. Taken from an altitude of about 60,000 miles above the planet, at an infrared wavelength of 2.3 microns (about three times the longest wavelength visible to the human eye) the map shows the turbulent, cloudy middle atmosphere some 30-33 miles above the surface, 6-10 miles below the visible cloudtops. The image to the left shows the radiant heat from the lower atmosphere (about 400 degrees Fahrenheit) shining through the sulfuric acid clouds, which appear as much as 10 times darker than the bright gaps between clouds. This cloud layer is at about -30 degrees Fahrenheit, at a pressure about 1/2 Earth's atmospheric pressure. About 2/3 of the dark hemisphere is visible, centered on longitude 350 West, with bright slivers of daylit high clouds visible at top and bottom left. The right image, a modified negative, represents what scientists believe would be the visual appearance of this mid-level cloud deck in daylight, with the clouds reflecting sunlight instead of blocking out infrared from the hot planet and lower atmosphere. Near the equator, the clouds appear fluffy and blocky; farther north, they are stretched out into East-West filaments by winds estimated at more than 150 mph, while the poles are capped by thick clouds at this altitude. The Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft is a combined mapping (imaging) and spectral instrument. It can sense 408 contiguous wavelengths from 0.7 microns (deep red) to 5.2 microns, and can construct a map or image by mechanical scanning. It can spectroscopically analyze atmospheres and surfaces and construct thermal and chemical maps. Designed and operated by scientists and engineers at the Jet Propulsion Laboratory, NIMS involves 15 scientists in the U.S., England, and France. The Galileo Project is managed for NASA's Office of Space Science and Applications by JPL; its mission is to study the planet Jupiter and its satellites and magnetosphere after multiple gravity-assist flybys at Venus and the Earth.

The Distribution of Lightning Channel Lengths in Northern Alabama Thunderstorms

NASA Technical Reports Server (NTRS)

Peterson, H. S.; Koshak, W. J.

2010-01-01

Lightning is well known to be a major source of tropospheric NOx, and in most cases is the dominant natural source (Huntreiser et al 1998, Jourdain and Hauglustaine 2001). Production of NOx by a segment of a lightning channel is a function of channel segment energy density and channel segment altitude. A first estimate of NOx production by a lightning flash can be found by multiplying production per segment [typically 104 J/m; Hill (1979)] by the total length of the flash s channel. The purpose of this study is to determine average channel length for lightning flashes near NALMA in 2008, and to compare average channel length of ground flashes to the average channel length of cloud flashes.

Economic impact of climate on water management in Oklahoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eddy, A.

1981-08-01

Topics and authors are listed below: The Oklahoma Water Plan, Jim Schuelin; The Garber-Wellington Research Project, Odell Morgan; The Tulsa Urban Study, Howard Chalker; Some Civil Defense/Flood Warning Problems, Ron Hill; The Impact of Climate on Rural Water Management, Ellen Cooter; Economic Models for Water Resource and Climate Impact Applications, William S. Cooter; Flood Forecasting, Jack Bowman; Small Basin Rainfall Characteristics via Factor Analysis, John M. Harlin; Radar Clouds Over Oklahoma, Bernard N. Meisner; The Oklahoma Climatological Survey Data Bank, Amos Eddy; Derived Variables: Climatic and Hydrologic Data from Weather Station Records, Jayne M. Salisbury; Precipitation Estimates Using Radar, Kenmore » Wilk and David Zittel; and A Water Control Data System, Joe Z. Durham.« less

Coastal management politics: a view from Capitol Hill

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kitsos, T.R.

The Coastal Zone Management Act (CZMA) of 1972 emerged from the national debate about land use in the late 1960s and early 1970s. Despite public support for environmental protection, enactment of the CZMA was clouded by a gloomy prognosis and by the lack of presidential enthusiasm for the program. The author traces the evolution of political forces that helped to establish and sustain coastal management as a federal function during the program's first decade; identifies the support of coastal state congressmen as the most important single factor in the program's survival; and raises questions about the capacity of legislative effortsmore » to respond to the current budgetary austerity of the Reagan administration. 17 references.« less

Water ice clouds on Mars: a study of partial cloudiness with a global climate model and MARCI data

NASA Astrophysics Data System (ADS)

Pottier, Alizée; Montmessin, Franck; Forget, François; Wolff, Mike; Navarro, Thomas; Millour, Ehouarn; Madeleine, Jean-Baptiste; Spiga, Aymeric; Bertrand, Tanguy

2015-04-01

There is a large reservoir of water ice on Mars in the polar caps, that sublimates in summer and releases water vapor. Water is then advected in the atmospheric circulation that evolves seasonally. This vapor forms clouds, frost, and can also be adsorbed in the soil. In a global study of the water cycle, water ice clouds play a key part in the martian climate. There is a need to understand better their distribution and radiative effect. The tool used in this study is the global climate model (GCM) of the Laboratoire de Météorologie Dynamique. It is made up of a core that computes fluid dynamics, and a physical part that gathers a number of parametrised processes. It includes tracers and the condensation and sublimation of water in the atmosphere and on the ground, allowing a study of the complete water cycle. To improve the representation of water ice clouds in the model, a new parametrisation of partial cloudiness has been implemented and will be presented. Indeed, model cells are hundreds of kilometers wide, and it is quite unrealistic to suppose that cloud coverage is always uniform in them. Furthermore, the model was quite unstable since the implementation of the radiative effect of clouds, and partial cloudiness had the effect of reducing this instability. In practice, a subgrid temperature distribution is supposed, and the temperature computed in the model is interpreted as its mean. The subgrid scale temperature distribution is simple, and its width is a free parameter. Using this distribution, the fraction of the grid cells under the water vapor condensation temperature is interpreted as the fraction of the cell in which clouds form (or cloud fraction). From these fractions at each height a total partial cloudiness (the clouds as seen from the orbit) is deduced. The radiative transfer is computed twice, for the clear area and for the cloudy one. Observing the water cycle with this new parametrisation, some differences are seen with standard runs. These changes mainly affect the aphelion cloud belt and the polar hoods. Partial cloudiness is compared to higher resolution (one per one degree) runs in which cloudiness diagnostics are done. MARCI data of cloud opacity is also used to verify the predicted water ice cloud distribution and patchiness. The aim is to understand the causes of patchiness and to validate the choice of a subgrid scale temperature distribution. There are seasonal variations, recurring patterns near major topographical features.

Analysis of TRMM Microphysical Measurements: Tropical Rainfall Measuring Mission (TRMM)

NASA Technical Reports Server (NTRS)

2004-01-01

SPEC Incorporated participated in three of the four TRMM field campaigns (TEFLUN-A, TEFLUN-B and KWAJEX), installing and operating a cloud particle imager (CPI) and a high volume precipitation spectrometer (HVPS) on the SPEC Learjet in TEFLUN-A, the University of North Dakota Citation in TEFLUN-B and KWAJEX, and a CPI on the NASA DC-8 in KWAJEX. This report presents and discusses new software tools and algorithms that were developed to analyze microphysical data collected during these field campaigns, as well as scientific interpretations of the data themselves. Software algorithms were developed to improve the analysis of microphysical measurements collected by the TRMM aircraft during the field campaigns. Particular attention was paid to developing and/or improving algorithms used to compute particle size distributions and ice water content. Software was also developed in support of production of the TRMM Common Microphysical Product (CMP) data files. CMP data files for TEFLUN-A field campaign were produced and submitted to the DAAC. Typical microphysical properties of convective and stratiform regions from TEFLUN-A and KWAJEX clouds were produced. In general, it was found that in the upper cloud region near -20 to -25 C, stratiform clouds contain very high (greater than 1 per cubic centimeter) concentrations of small ice particles, which are suspected to be a residual from homogeneous freezing and sedimentation of small drops in a convective updraft. In the upper cloud region near -20 to -25 C, convective clouds contain aggregates, which are not found lower in the cloud. Stratiform clouds contain aggregates at all levels, with the majority in the lowest levels. Convective cloud regions contain much higher LWC and drop concentrations than stratiform regions at all levels, and higher LWC in the middle and upper regions. Stratiform clouds contain higher IWC than convective clouds only at the lowest level. Irregular shaped ice particles are found in very high concentrations throughout both convective and stratiform cloud regions. A striking difference in particle shape in cirrus formed in situ, cirrus formed from maritime anvils and cirrus formed from continental anvils. Over 50% of the mass of in situ cirrus ice particles is composed of bullet rosettes, while bullet rosettes are virtually non-existent in maritime and tropical anvils. Tropical anvils are composed of mostly singular, plates, capped columns, and blocky irregular shapes, while continental anvils have a much higher percentage of aggregates, some of which are chains of small spheroidal particles that appear to result from homogeneous freezing of drops. A correlation between high electric fields in continental anvils and the formation of aggregates is hypothesized.

Upper Thermosphere Winds and Temperatures in the Geomagnetic Polar Cap: Solar Cycle, Geomagnetic Activity, and Interplanetary Magnetic Field Dependencies

NASA Technical Reports Server (NTRS)

Killeen, T. L.; Won, Y.-I.; Niciejewski, R. J.; Burns, A. G.

1995-01-01

Ground-based Fabry-Perot interferometers located at Thule, Greenland (76.5 deg. N, 69.0 deg. W, lambda = 86 deg.) and at Sondre Stromfjord, Greenland (67.0 deg. N, 50.9 deg. W, lambda = 74 deg.) have monitored the upper thermospheric (approx. 240-km altitude) neutral wind and temperature over the northern hemisphere geomagnetic polar cap since 1983 and 1985, respectively. The thermospheric observations are obtained by determining the Doppler characteristics of the (OI) 15,867-K (630.0-nm) emission of atomic oxygen. The instruments operate on a routine, automatic, (mostly) untended basis during the winter observing seasons, with data coverage limited only by cloud cover and (occasional) instrument failures. This unique database of geomagnetic polar cap measurements now extends over the complete range of solar activity. We present an analysis of the measurements made between 1985 (near solar minimum) and 1991 (near solar maximum), as part of a long-term study of geomagnetic polar cap thermospheric climatology. The measurements from a total of 902 nights of observations are compared with the predictions of two semiempirical models: the Vector Spherical Harmonic (VSH) model of Killeen et al. (1987) and the Horizontal Wind Model (HWM) of Hedin et al. (1991). The results are also analyzed using calculations of thermospheric momentum forcing terms from the Thermosphere-ionosphere General Circulation Model TGCM) of the National Center for Atmospheric Research (NCAR). The experimental results show that upper thermospheric winds in the geomagnetic polar cap have a fundamental diurnal character, with typical wind speeds of about 200 m/s at solar minimum, rising to up to about 800 m/s at solar maximum, depending on geomagnetic activity level. These winds generally blow in the antisunward direction, but are interrupted by episodes of modified wind velocity and altered direction often associated with changes in the orientation of the Interplanetary Magnetic Field (IMF). The central polar cap (greater than approx. 80 magnetic latitude) antisunward wind speed is found to be a strong function of both solar and geomagnetic activity. The polar cap temperatures show variations in both solar and geomagnetic activity, with temperatures near 800 K for low K(sub p) and F(sub 10.7) and greater than about 2000 K for high K(sub p) and F(sub 10.7). The observed temperatures are significantly greater than those predicted by the mass spectrometer/incoherent scatter model for high activity conditions. Theoretical analysis based on the NCAR TIGCM indicates that the antisunward upper thermospheric winds, driven by upstream ion drag, basically 'coast' across the polar cap. The relatively small changes in wind velocity and direction within the polar cap are induced by a combination of forcing terms of commensurate magnitude, including the nonlinear advection term, the Coriolis term, and the pressure gradient force term. The polar cap thennospheric thermal balance is dominated by horizontal advection, and adiabatic and thermal conduction terms.

Mapping forest height, foliage height profiles and disturbance characteristics with time series of gap-filled Landsat and ALI imagery

NASA Astrophysics Data System (ADS)

Helmer, E.; Ruzycki, T. S.; Wunderle, J. M.; Kwit, C.; Ewert, D. N.; Voggesser, S. M.; Brandeis, T. J.

2011-12-01

We mapped tropical dry forest height (RMSE = 0.9 m, R2 = 0.84, range 0.6-7 m) and foliage height profiles with a time series of gap-filled Landsat and Advanced Land Imager (ALI) imagery for the island of Eleuthera, The Bahamas. We also mapped disturbance type and age with decision tree classification of the image time series. Having mapped these variables in the context of studies of wintering habitat of an endangered Nearctic-Neotropical migrant bird, the Kirtland's Warbler (Dendroica kirtlandii), we then illustrated relationships between forest vertical structure, disturbance type and counts of forage species important to the Kirtland's Warbler. The ALI imagery and the Landsat time series were both critical to the result for forest height, which the strong relationship of forest height with disturbance type and age facilitated. Also unique to this study was that seven of the eight image time steps were cloud-gap-filled images: mosaics of the clear parts of several cloudy scenes, in which cloud gaps in a reference scene for each time step are filled with image data from alternate scenes. We created each cloud-cleared image, including a virtually seamless ALI image mosaic, with regression tree normalization of the image data that filled cloud gaps. We also illustrated how viewing time series imagery as red-green-blue composites of tasseled cap wetness (RGB wetness composites) aids reference data collection for classifying tropical forest disturbance type and age.

Titan's cloud seasonal activity from winter to spring with Cassini/VIMS

USGS Publications Warehouse

Rodriguez, S.; Le, Mouelic S.; Rannou, P.; Sotin, Christophe; Brown, R.H.; Barnes, J.W.; Griffith, C.A.; Burgalat, J.; Baines, K.H.; Buratti, B.J.; Clark, R.N.; Nicholson, P.D.

2011-01-01

Since Saturn orbital insertion in July 2004, the Cassini orbiter has been observing Titan throughout most of the northern winter season (October 2002-August 2009) and the beginning of spring, allowing a detailed monitoring of Titan's cloud coverage at high spatial resolution with close flybys on a monthly basis. This study reports on the analysis of all the near-infrared images of Titan's clouds acquired by the Visual and Infrared Mapping Spectrometer (VIMS) during 67 targeted flybys of Titan between July 2004 and April 2010.The VIMS observations show numerous sporadic clouds at southern high and mid-latitudes, rare clouds in the equatorial region, and reveal a long-lived cloud cap above the north pole, ubiquitous poleward of 60??N. These observations allow us to follow the evolution of the cloud coverage during almost a 6-year period including the equinox, and greatly help to further constrain global circulation models (GCMs). After 4. years of regular outbursts observed by Cassini between 2004 and 2008, southern polar cloud activity started declining, and completely ceased 1. year before spring equinox. The extensive cloud system over the north pole, stable between 2004 and 2008, progressively fractionated and vanished as Titan entered into northern spring. At southern mid-latitudes, clouds were continuously observed throughout the VIMS observing period, even after equinox, in a latitude band between 30??S and 60??S. During the whole period of observation, only a dozen clouds were observed closer to the equator, though they were slightly more frequent as equinox approached. We also investigated the distribution of clouds with longitude. We found that southern polar clouds, before disappearing in mid-2008, were systematically concentrated in the leading hemisphere of Titan, in particular above and to the east of Ontario Lacus, the largest reservoir of hydrocarbons in the area. Clouds are also non-homogeneously distributed with longitude at southern mid-latitudes. The n= 2-mode wave pattern of the distribution, observed since 2003 by Earth-based telescopes and confirmed by our Cassini observations, may be attributed to Saturn's tides. Although the latitudinal distribution of clouds is now relatively well reproduced and understood by the GCMs, the non-homogeneous longitudinal distributions and the evolution of the cloud coverage with seasons still need investigation. If the observation of a few single clouds at the tropics and at northern mid-latitudes late in winter and at the start of spring cannot be further interpreted for the moment, the obvious shutdown of the cloud activity at Titan's poles provides clear signs of the onset of the general circulation turnover that is expected to accompany the beginning of Titan's northern spring. According to our GCM, the persistence of clouds at certain latitudes rather suggests a 'sudden' shift in near future of the meteorology into the more illuminated hemisphere. Finally, the observed seasonal change in cloud activity occurred with a significant time lag that is not predicted by our model. This may be due to an overall methane humidity at Titan's surface higher than previously expected. ?? 2011 Elsevier Inc.

Crew Earth Observations (CEO) taken during STS-113

NASA Image and Video Library

2002-12-04

STS113-708-014 (23 November - 7 December 2002) --- The STS-113 crewmembers used a handheld 70mm still camera to record this image of Patagonia lakes in southern Argentina. The lowest of the three lakes in this view is Lake Argentino. The next one north (middle lake) is Lake Viedma, and the lake on the top margin is Lake San Martín. According to NASA scientists studying the STS-113 Earth imagery, all three of these large lakes have been carved out by glaciers in the "recent" ice age, descending from the Andes Mountains (under cloud along the right side of the view). Three glacier tongues can be discerned as small white features leading into the western (left) ends of each lake. The rounded ends of the lakes, according to the Johnson Space Center scientists, are produced by the slow "flowing" action of glacial ice on the plains next to the mountain chain. Snow cap on lower peaks next to the cloud make a jagged pattern.

Buoyant production and consumption of turbulence kinetic energy in cloud-topped mixed layers

NASA Technical Reports Server (NTRS)

Randall, D. A.

1984-01-01

It is pointed out that studies of the entraining planetary boundary layer (PBL) have generally emphasized the role of buoyancy fluxes in driving entrainment. The buoyancy flux is proportional to the rate of conversion of the potential energy of the mean flow into the kinetic energy of the turbulence. It is not unusual for conversion to proceed in both directions simultaneously. This occurs, for instance, in both clear and cloudy convective mixed layers which are capped by inversions. A partitioning of the net conversion into positive parts, generating turbulence kinetic energy (TKE), and negative parts (TKE-consuming), would make it possible to include the positive part in the gross production rate, and closure would be achieved. Three different approaches to partitioning have been proposed. The present investigation is concerned with a comparison of the three partitioning theories. Particular attention is given to the cloud-topped mixed layer because in this case the differences between two partitioning approaches are most apparent.

Global measurements of coarse-mode aerosol size distributions - first results from the Atmospheric Tomography Mission (ATom)

NASA Astrophysics Data System (ADS)

Weinzierl, B.; Dollner, M.; Schuh, H.; Brock, C. A.; Bui, T. V.; Gasteiger, J.; Froyd, K. D.; Schwarz, J. P.; Spanu, A.; Murphy, D. M.; Katich, J. M.; Kupc, A.; Williamson, C.

2016-12-01

Although coarse-mode aerosol (>1 µm diameter), composed mainly of mineral dust and sea-salt, is highly abundant over large regions of the world, these particles form a particularly poorly understood and characterized subset of atmospheric aerosol constituents. The NASA-sponsored Atmospheric Tomography Mission (ATom) is an unprecedented field program that investigates how human emissions affect air quality and climate change. ATom provides a singular opportunity to characterize the global coarse-mode size distribution by continuously profiling between 0.2 and 13 km with the NASA DC-8 research aircraft while traveling from the high Arctic down south the middle of the Pacific Ocean, to the Southern Ocean and back north over the Atlantic Ocean basin in four seasons. For ATom, the DC-8 aircraft has been equipped with multiple instruments to observe the composition of the air. The coarse mode and cloud particle size distribution is measured in-situ with a Cloud, Aerosol, and Precipitation Spectrometer (CAPS) mounted under the wing of the DC-8 research aircraft. The CAPS consists of an optical spectrometer providing size distributions in the size range between 0.5 and 50 µm and an imager detecting number concentration, size and shape of particles between 15 and 930 µm diameter. Early ATom flights indicated complicated vertical layering: over the sea, we regularly observed sea salt aerosol which extended from the ground up to 0.6-1 km altitude. In addition - depending on the location of the measurements - we frequently found layers with coarse mode aerosol originating from deserts and biomass burning aerosol aloft. In this study, we will present first results of coarse mode aerosol observations from the entire first ATom deployment in summer 2016. We will show vertical profiles of coarse mode aerosol number concentration, discuss their interhemispheric differences, and look into the question how frequently coarse-mode aerosol is externally mixed with submicron black carbon and other anthropogenic aerosol components. Furthermore, we will compare sequences with mineral dust observations made during ATom with results from the Saharan Aerosol Long-range Transport and Aerosol Cloud Interaction Experiment (SALTRACE) that took place around the tropical and northern Atlantic basin in 2013.

Deposition and immersion-mode nucleation of ice by three distinct samples of volcanic ash

NASA Astrophysics Data System (ADS)

Schill, G. P.; Genareau, K.; Tolbert, M. A.

2015-07-01

Ice nucleation of volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui eruption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225 to 235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited appreciable heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

The zonal-mean and regional tropospheric pressure responses to changes in ionospheric potential

NASA Astrophysics Data System (ADS)

Zhou, Limin; Tinsley, Brian; Wang, Lin; Burns, Gary

2018-06-01

Global reanalysis data reveal daily surface pressure responses to changes in the global ionospheric potential in both polar and sub-polar regions. We use 21 years of data to show that the pressure response to externally-induced ionospheric potential changes, that are due to the interplanetary magnetic field east-west (IMF By) component, are present in two separate decadal intervals, and follow the opposite ionospheric potential changes in the Arctic and Antarctic for a given By. We use the 4 years of available data to show that the pressure responses to changes in internally generated ionospheric potential, that are caused by low-latitude thunderstorms and highly electrified clouds, agree in sign and sensitivity with those externally generated. We have determined that the daily varying pressure responses are stronger in local winter and spring. The pressure responses at polar latitudes are predominantly over the Antarctic and Greenland ice caps, and those at sub-polar latitudes are of opposite sign, mainly over oceans. A lead-lag analysis confirms that the responses maximize within two days of the ionospheric potential input. Regions of surface pressure fluctuating by about 4 hPa in winter are found with ionospheric potential changes of about 40 kV. The consistent pressure response to the independent external and internal inputs strongly supports the reality of a cloud microphysical mechanism affected by the global electric circuit. A speculative mechanism involves the ionosphere-earth current density Jz, which produces space charge at cloud boundaries and electrically charged droplets and aerosol particles. Ultrafine aerosol particles, under the action of electro-anti-scavenging, are enabled to grow to condensation nuclei size, affecting cloud microphysics and cloud opacity and surface pressure on time scales of hours.

Unraveling the martian water cycle with high-resolution global climate simulations

NASA Astrophysics Data System (ADS)

Pottier, Alizée; Forget, François; Montmessin, Franck; Navarro, Thomas; Spiga, Aymeric; Millour, Ehouarn; Szantai, André; Madeleine, Jean-Baptiste

2017-07-01

Global climate modeling of the Mars water cycle is usually performed at relatively coarse resolution (200 - 300km), which may not be sufficient to properly represent the impact of waves, fronts, topography effects on the detailed structure of clouds and surface ice deposits. Here, we present new numerical simulations of the annual water cycle performed at a resolution of 1° × 1° (∼ 60 km in latitude). The model includes the radiative effects of clouds, whose influence on the thermal structure and atmospheric dynamics is significant, thus we also examine simulations with inactive clouds to distinguish the direct impact of resolution on circulation and winds from the indirect impact of resolution via water ice clouds. To first order, we find that the high resolution does not dramatically change the behavior of the system, and that simulations performed at ∼ 200 km resolution capture well the behavior of the simulated water cycle and Mars climate. Nevertheless, a detailed comparison between high and low resolution simulations, with reference to observations, reveal several significant changes that impact our understanding of the water cycle active today on Mars. The key northern cap edge dynamics are affected by an increase in baroclinic wave strength, with a complication of northern summer dynamics. South polar frost deposition is modified, with a westward longitudinal shift, since southern dynamics are also influenced. Baroclinic wave mode transitions are observed. New transient phenomena appear, like spiral and streak clouds, already documented in the observations. Atmospheric circulation cells in the polar region exhibit a large variability and are fine structured, with slope winds. Most modeled phenomena affected by high resolution give a picture of a more turbulent planet, inducing further variability. This is challenging for long-period climate studies.

Measurements of cloud condensation nuclei activity and droplet activation kinetics of fresh unprocessed regional dust samples and minerals

NASA Astrophysics Data System (ADS)

Kumar, P.; Sokolik, I. N.; Nenes, A.

2011-04-01

This study reports laboratory measurements of cloud condensation nuclei (CCN) activity and droplet activation kinetics of aerosols dry generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. Based on the observed dependence of critical supersaturation, sc, with particle dry diameter, Ddry, we found that FHH (Frenkel, Halsey and Hill) adsorption activation theory is a far more suitable framework for describing fresh dust CCN activity than Köhler theory. One set of FHH parameters (AFHH ∼ 2.25 ± 0.75, BFHH ∼ 1.20 ± 0.10) can adequately reproduce the measured CCN activity for all species considered, and also explains the large range of hygroscopicities reported in the literature. Based on a threshold droplet growth analysis, mineral dust aerosols were found to display retarded activation kinetics compared to ammonium sulfate. Comprehensive simulations of mineral dust activation and growth in the CCN instrument suggest that this retardation is equivalent to a reduction of the water vapor uptake coefficient (relative to that for calibration ammonium sulfate aerosol) by 30-80%. These results suggest that dust particles do not require deliquescent material to act as CCN in the atmosphere.

Simulated CO2 Snowfalls and Baroclinic Waves in the Northern Winter Polar Atmosphere on Mars: Feasibility of Forecasts

NASA Astrophysics Data System (ADS)

Kuroda, T.; Medvedev, A. S.; Kasaba, Y.; Hartogh, P.

2013-12-01

The seasonal CO2 polar cap is formed from ice particles that have fallen from the atmosphere as well as those condensed directly on the surface. The possible occurrence of CO2 snowfall in the winter polar regions have been observed, and previous simulation studies have indicated that the longitudinal irregularities of CO2 ice clouds in the northern polar region seemed to be linked to local weather phenomena. Transient planetary waves are the prominent dynamical feature during northern winters in the martian atmosphere, and this study focuses on revealing the mechanism of how the dynamical influence of transient planetary waves affects the occurrences of CO2 ice clouds, snowfalls and formations of seasonal CO2 polar cap in high latitudes during northern winters. The DRAMATIC (Dynamics, RAdiation, MAterial Transport and their mutual InteraCtions) MGCM, which is used for this study, is based on a Japanese terrestrial model (CCSR/NIES/FRCGC MIROC) with a spectral solver for the three-dimensional primitive equations. In this simulation the horizontal resolution is set at about 5.6° × 5.6° (~333 km at equator), the vertical grid consists of 69 σ-levels with the top of the model at about 100 km. Realistic topography, albedo, thermal inertia and roughness data for the Mars surface are included. Radiative effects of CO2 gas (considering only LTE) and dust, in solar and infrared wavelengths, are taken into account. We have implemented a simple scheme representing the formation and transport of CO2 ice clouds into our MGCM, and investigated snowfall in high latitudes during northern winters. The MGCM simulations showed that the CO2 ice clouds are formed at altitudes of up to ~40 km in the northern polar region (northward of 70° N) during winter, which is consistent with the observations (MRO-MCS and MGS-MOLA). In addition, we found that the occurrence of the CO2 ice clouds correlated to a large degree with the cold phases of transient planetary waves. In the altitudes above ~15 km, the cloud formations are very much aligned with the baroclinic waves with zonal wavenumber of 1 and 5-6 sols period. In the lower altitudes the baroclinic waves components with shorter periods (~3 sols) also affect the cloud formations. The fate of ice particles during sedimentation depends on the thermal structure below because it takes ~0.2 sols for particles to descend from 25 km to the surface, which is much shorter than the periods of the transient waves. We found that ice particles formed up to ~20 km can reach the surface in the form of snowfall in certain longitude regions (in 30° W-60° E), while in others these particles likely sublimate in the lower warmer atmospheric layers. Given the regular nature of such atmospheric waves on Mars, the results of this study suggest that the snowstorms may be predicted several weeks in advance. It is simply impossible to predict the snowfall somewhere on Earth in such a long time ahead, but this may be different on Mars. For missions to Mars aiming to explore these regions with rovers, such weather forecasts would offer the possibility of choosing a route that avoids heavy snow storms.

Validation of the large-scale Lagrangian cirrus model CLaMS-Ice by in-situ measurements

NASA Astrophysics Data System (ADS)

Costa, Anja; Rolf, Christian; Grooß, Jens-Uwe; Afchine, Armin; Spelten, Nicole; Dreiling, Volker; Zöger, Martin; Krämer, Martina

2015-04-01

Cirrus clouds are an element of uncertainty in the climate system and have received increasing attention since the last IPCC reports. The interaction of varying freezing meachanisms, sedimentation rates, temperature and updraft velocity fluctuations and other factors that lead to the formation of those clouds is still not fully understood. During the ML-Cirrus campaign 2014 (Germany), the new cirrus cloud model CLaMS-Ice (see Rolf et al., EGU 2015) has been used for flight planning to direct the research aircraft HALO into interesting cirrus cloud regions. Now, after the campaign, we use our in-situ aircraft measurements to validate and improve this model - with the long-term goal to enable it to simulate cirrus cloud cover globally, with reasonable computing times and sufficient accuracy. CLaMS-Ice consists of a two-moment bulk model established by Spichtinger and Gierens (2009a, 2009b), which simulates cirrus clouds along trajectories that the Lagrangian model CLaMS (McKenna et al., 2002 and Konopka et al. 2007) derived from ECMWF data. The model output covers temperature, pressure, relative humidity, ice water content (IWC), and ice crystal numbers (Nice). These parameters were measured on board of HALO by the following instruments: temperature and pressure by BAHAMAS, total and gas phase water by the hygrometers FISH and SHARC (see Meyer et al 2014, submitted to ACP), and Nice as well as ice crystal size distributions by the cloud spectrometer NIXE-CAPS (see also Krämer et al., EGU 2015). Comparisons of the model results with the measurements yield that cirrus clouds can be successfully simulated by CLaMS-Ice. However, there are sections in which the model's relative humidity and Nice deviate considerably from the measured values. This can be traced back to e.g. the initialization of total water from ECMWF data. The simulations are therefore reinitiated with the total water content measured by FISH. Other possible sources of uncertainties are investigated, as imposed temperature fluctuations, numbers and efficencies of heterogeneous ice nuclei or assumptions concerning the sedimentation rates. This contribution sums up the results of these investigations and outlines future work on CLaMS-Ice, that will lead to a tool helping to understand the cirrus clouds under the different environmental conditions during ML-Cirrus.

SST Variation Due to Interactive Convective-Radiative Processes

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Shie, C.-L.; Johnson, D.; Simpson, J.; Li, X.; Sui, C.-H.

2000-01-01

The recent linking of Cloud-Resolving Models (CRMs) to Ocean-Mixed Layer (OML) models has provided a powerful new means of quantifying the role of cloud systems in ocean-atmosphere coupling. This is due to the fact that the CRM can better resolve clouds and cloud systems and allow for explicit cloud-radiation interaction. For example, Anderson (1997) applied an atmospheric forcing associated with a CRM simulated squall line to a 3-D OML model (one way or passive interaction). His results suggested that the spatial variability resulting from the squall forcing can last at least 24 hours when forced with otherwise spatially uniform fluxes. In addition, the sea surface salinity (SSS) variability continuously decreased following the forcing, while some of the SST variability remained when a diurnal mixed layer capped off the surface structure. The forcing used in the OML model, however, focused on shorter time (8 h) and smaller spatial scales (100-120 km). In this study, the 3-D Goddard Cumulus Ensemble Model (GCE; 512 x 512 x 23 cu km, 2-km horizontal resolution) is used to simulate convective active episodes occurring in the Western Pacific warm pool and Eastern Atlantic regions. The model is integrated for seven days, and the simulated results are coupled to an OML model to better understand the impact of precipitation and changes in the planetary boundary layer upon SST variation. We will specifically examine and compare the results of linking the OML model with various spatially-averaged outputs from GCE simulations (i.e., 2 km vs. 10-50 km horizontal resolutions), in order to help understand the SST sensitivity to multi-scale influences. This will allow us to assess the importance of explicitly simulated deep and shallow clouds, as well as the subgrid-scale effects (in coarse-model runs) upon SST variation. Results using both 1-D and 2-D OML models will be evaluated to assess the effects of horizontal advection.

Backscatter-to-Extinction Ratios in the Top Layers of Tropical Mesoscale Convective Systems and in Isolated Cirrus from LITE Observations

NASA Technical Reports Server (NTRS)

Platt, C. M. R.; Winker, D. M.; Vaughan, M. A.; Miller, S. D.

1999-01-01

Cloud-integrated attenuated backscatter from observations with the Lidar In-Space Technology Experiment (LITE) was studied over a range of cirrus clouds capping some extensive mesoscale convective systems (MCSS) in the Tropical West Pacific. The integrated backscatter when the cloud is completely attenuating, and when corrected for multiple scattering, is a measure of the cloud particle backscatter phase function. Four different cases of MCS were studied. The first was very large, very intense, and fully attenuating, with cloud tops extending to 17 km and a maximum lidar pulse penetration of about 3 km. It also exhibited the highest integrated attenuated isotropic backscatter, with values in the 532-nm channel of up to 2.5 near the center of the system, falling to 0.6 near the edges. The second MCS had cloud tops that extended to 14.8 km. Although MCS2 was almost fully attenuating, the pulse penetration into the cloud was up to 7 km and the MCS2 had a more diffuse appearance than MCS1. The integrated backscatter values were much lower in this system but with some systematic variations between 0.44 and 0.75. The third MCS was Typhoon Melissa. Values of integrated backscatter in tt-ds case varied from 1.64 near the eye of the typhoon to between 0.44 and 1.0 in the areas of typhoon outflow and in the 532-nm channel. Mean pulse penetration through the cloud top was 2-3 km, the lowest penetration of any of the systems. The fourth MCS consisted of a region of outflow from Typhoon Melissa. The cloud was semitransparent for more than half of the image time. During that time, maximum cloud depth was about 7 km. The integrated backscatter varied from about 0.38 to 0.63 in the 532-nm channel when the cloud was fully attenuating. In some isolated cirrus between the main systems, a plot of integrated backscatter against one minus the two-way transmittance gave a linear dependence with a maximum value of 0.35 when the clouds were fully attenuating. The effective backscatter-to-extinction ratios, when allowing for different multiple-scattering factors from space, were often within the range of those observed with ground-based lidar. Exceptions occurred near the centers of the most intense convection, where values were measured that were considerably higher than those in cirrus observed from the surface. In this case, the values were more compatible with theoretical values for perfectly formed hexagonal columns or plates. The large range in theoretically calculated back- scatter-to-extinction ratio and integrated multiple-scattering factor precluded a closer interpretation in terms of cloud microphysics.

Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific coastal marine stratocumulus during VOCALS-REx

NASA Astrophysics Data System (ADS)

Zheng, X.; Albrecht, B.; Jonsson, H. H.; Khelif, D.; Feingold, G.; Minnis, P.; Ayers, K.; Chuang, P.; Donaher, S.; Rossiter, D.; Ghate, V.; Ruiz-Plancarte, J.; Sun-Mack, S.

2011-05-01

Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. The BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL on days without predominately synoptic and meso-scale influences. The BL had a depth of 1140 ± 120 m, was well-mixed and capped by a sharp inversion. The wind direction generally switched from southerly within the BL to northerly above the inversion. The cloud liquid water path (LWP) varied between 15 g m-2 and 160 g m-2. From 29 October to 4 November, when a synoptic system affected conditions at Point Alpha, the cloud LWP was higher than on the other days by around 40 g m-2. On 1 and 2 November, a moist layer above the inversion moved over Point Alpha. The total-water specific humidity above the inversion was larger than that within the BL during these days. Entrainment rates (average of 1.5 ± 0.6 mm s-1) calculated from the near cloud-top fluxes and turbulence (vertical velocity variance) in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The accumulation mode aerosol varied from 250 to 700 cm-3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm-3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm-3, which was consistent with the satellite-derived values. The relationship of cloud droplet number concentration and CCN at 0.2 % supersaturation from 18 flights is Nd =4.6 × CCN0.71. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft {in situ} observations near cloud top. The aerosol and cloud LWP relationship reveals that during the typical well-mixed BL days the cloud LWP increased with the CCN concentrations. On the other hand, meteorological factors and the decoupling processes have large influences on the cloud LWP variation as well.

HUBBLE WATCHES THE RED PLANET AS MARS GLOBAL SURVEYOR BEGINS AEROBRAKING

NASA Technical Reports Server (NTRS)

2002-01-01

his NASA Hubble Space Telescope picture of Mars was taken on Sept. 12, one day after the arrival of the Mars Global Surveyor (MGS) spacecraft and only five hours before the beginning of autumn in the Martian northern hemisphere. (Mars is tilted on its axis like Earth, so it has similar seasonal changes, including an autumnal equinox when the Sun crosses Mars' equator from the northern to the southern hemisphere). This Hubble picture was taken in support of the MGS mission. Hubble is monitoring the Martian weather conditions during the early phases of MGS aerobraking; in particular, the detection of large dust storms are important inputs into the atmospheric models used by the MGS mission to plan aerobraking operations. Though a dusty haze fills the giant Hellas impact basin south of the dark fin-shaped feature Syrtis Major, the dust appears to be localized within Hellas. Unless the region covered expands significantly, the dust will not be of concern for MGS aerobraking. Other early signs of seasonal transitions on Mars are apparent in the Hubble picture. The northern polar ice cap is blanketed under a polar hood of clouds that typically start forming in late northern summer. As fall progresses, sunlight will dwindle in the north polar region and the seasonal polar cap of frozen carbon dioxide will start condensing onto the surface under these clouds. Hubble observations will continue until October 13, as MGS carefully uses the drag of the Martian atmosphere to circularize its orbit about the Red Planet. After mid-October, Mars will be too close to the Sun, in angular separation, for Hubble to safely view. The image is a composite of three separately filtered colored images taken with the Wide Field Planetary Camera 2 (WFPC2). Resolution is 35 miles (57 kilometers) per pixel (picture element). The Pathfinder landing site near Ares Valles is about 2200 miles (3600 kilometers) west of the center of this image, so was not visible during this observation. Mars was 158 million miles (255 million kilometers) from Earth at the time. [LEFT] An image of this region of Mars, taken in June 1997, is shown for comparison. The Hellas basin is filled with bright clouds and/or surface frost. More water ice clouds are visible across the planet than in the Sept. image, reflecting the effects of the changing season. Mars appears larger because it was 44 million miles (77 million kilometers) closer to Earth than in the September image. Credit: Phil James (Univ. Toledo) and Steve Lee (Univ. Colorado), and NASA

Particle Size of CO2 Condensates in Mars Atmosphere Revealed by Climate Sounder and Laser Ranging Observations

NASA Astrophysics Data System (ADS)

Hu, Renyu

Current-generation Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter (MRO) offers extensive coverage of the latitudinal and seasonal distribution of CO_2 condensation in Mars’s atmosphere. The atmospheric temperature profiles measured by MCS reveal that the thickness of CO_2 condensation layer reaches a maximum of 10-15 km (north) or ˜20 km (south) during the middle of winter. There is a shrinking of the CO_2 condensation layer from L_S ˜270(°) to ˜300(°) in 2007, probably related to a planet-encircling dust storm. We integrate the condensation area and the condensation occurrence rate synthesized from the MCS observations to estimate cumulative masses of CO2 condensates deposited onto the northern and southern seasonal polar caps. The mass loading of CO_2 condensate particles, when condensation occurs, can be independently inferred from the detections of reflective clouds by the Mars Orbiter Laser Altimetry (MOLA) onboard the Mars Global Surveyor (MGS). Therefore, we approximate the precipitation flux by the particle settling flux, which is estimated using the impulse responses of MOLA filter channels. With our approach, the total atmospheric condensation mass can be estimated from these observational data sets, with average particle size as the only free parameter. By comparison with the seasonal polar cap masses inferred from the time-varying gravity of Mars, our estimates indicate that the average condensate particle radius is 8 - 22 mum in the northern hemisphere and 4 - 13 mum in the southern hemisphere. This multi-instrument data analysis provides new constraints on modeling the microphysics of CO_2 clouds on Mars.

Interpretation of shallow electrical features from electromagnetic and magnetotelluric surveys at Mount Hood, Oregon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, N.E.; Mozley, E.; Wilt, M.

1982-04-10

A magnetotelluric survey was conducted at accessible locations around Mount Hood, Oregon. Thirty-eight tensor magnetotelluric (MT) and remote telluric stations were set up in clusters around the volcano except for the northwest quadrant, a wilderness area. Because of limited access, station locations were restricted to elevations below 1829 m. On the basis of the MT results, three areas were later investigated in more detail using a large-moment, controlled-source electromagnetic (EM) system. One-dimensional interpretations of EM and MT data on the northeast flank of the mountain near the Cloud Cap eruptive center and on the south flank near Timberline Lodge showmore » a similar subsurface resistivity pattern: a resistive surface layer 400--700 m thick, underlain by a conductive layer with variable thickness and resistivity of <20 ohm m. It is speculated that the surface layer consists of volcanics partially saturated with cold meteoric water. The underlying conductive zone is presumed to be volcanics saturated with water heated within the region of the central conduit and, possibly, at the Cloud Cap side vent. This hypothesis is supported by the existence of warm springs at the base of the mountain, most notably Swim Warm Springs on the south flank, and by several geothermal test wells, one of which penetrates the conductor south of Timberline Lodge. The mT data typically gave a shallower depth to the conductive zone than did the Em data. On the other hand, MT was better for resolving the thickness of the conductive layer and deeper structure. The MT data show evidence for a moderately conductive north-south structure on the south flank below the Timberline Lodge and for a broad zone of late Tertiary intrusives concealed on the southeast flank.« less

KSC-99padig047

NASA Image and Video Library

1999-12-17

After sunup, which is obscured by a cloud-filled sky, Space Shuttle Discovery waits atop the mobile launcher platform for launch of mission STS-103. At the top is seen the external tank gaseous oxygen vent arm system with the vent hood (commonly called the "beanie cap") poised above the external tank. The retractable arm and the beanie cap are designed to vent gaseous oxygen vapors away from the Space Shuttle. The arm truss section is 65 feet long and the diameter of the vent hood is 13 feet. Extending toward the cabin of the orbiter below is the orbiter access arm, with the environmental chamber (called the White Room) at the end. Through this chamber the crew enters the orbiter. The STS-103 mission, to service the Hubble Space Telescope, is scheduled for launch Dec. 17 at 8:47 p.m. EST. Mission objectives include replacing gyroscopes and an old computer, installing another solid state recorder, and replacing damaged insulation in the telescope. The mission is expected to last about 8 days and 21 hours. Discovery is expected to land at KSC Sunday, Dec. 26, at about 6:25 p.m. EST

View of the Earth seen by the Apollo 17 crew traveling toward the moon

NASA Image and Video Library

1972-12-07

AS17-148-22727 (7 Dec. 1972) --- This view of Earth was seen by the Apollo 17 crew as they traveled toward the moon on their NASA lunar landing mission. This outstanding trans-lunar coast photograph extends from the Mediterranean Sea area to the Antarctica south polar ice cap. This is the first time the Apollo trajectory made it possible to photograph the south polar ice cap. Note the heavy cloud cover in the Southern Hemisphere. Almost the entire coastline of Africa is clearly visible. The Arabian Peninsula can be seen at the northeastern edge of Africa. The large island off the coast of Africa is the Malagasy Republic. The Asian mainland is on the horizon toward the northeast. The Apollo 17 crew consisted of astronauts Eugene A. Cernan, mission commander; Ronald E. Evans, command module pilot; and Harrison H. Schmitt, lunar module pilot. While astronauts Cernan and Schmitt descended in the Lunar Module (LM) to explore the moon, astronaut Evans remained with the Command and Service Modules (CSM) in lunar orbit.

Terrestrial Ages of Antarctic Meteorites- Update 1999

NASA Technical Reports Server (NTRS)

Nishiizumi, Kunihiko; Welten, K. C.; Caffee, Marc W.

1999-01-01

We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36(half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-14 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the c,ap in half-life between 14-C and Cl-36 ages. We are now applying the new Ca-41- Cl-36 terrestrial age method as well as the Cl-36-Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary. We have measured Cl-36 in over 270 Antarctic meteorites since our previous compilation of terrestrial ages. Since a large number of meteorites have been recovered from many different icefields in Antarctica, we continue to survey the trends of terrestrial ages for different icefields. We have also measured detailed terrestrial ages vs. sample locations for Allan Hills, Elephant Moraine, and Lewis Cliff Icefields, where meteorites have been found with very long ages. The updated histograms of terrestrial ages of meteorites from the Allan Hills Main Icefield and Lewis Cliff Icefield are shown. These figures include C-14 ages obtained by the University of Arizona group. Pairs of meteorites are shown as one object for which the age is the average of all members of the same fall. The width of the bars represents 70,000 years, which was a typical uncertainty for Cl-36 ages. We reduced the uncertainty of terrestrial age determinations to approx. 40,000 years by using pairs of nuclides such as Ca-41-Cl-36 or Cl-36-Be-10. Meteorites found at the Allan Hills Icefields are much older than any other meteorites. The terrestrial ages cover a wide range and are as old as 2 My. Many of the Lewis Cliff meteorites are as old as the Allan Hills meteorites. So far, no clear correlation has been found between the terrestrial ages and the locations of the Lewis Cliff meteorites.

Direct damage to vegetation caused by acid rain and polluted cloud: definition of critical levels for forest trees.

PubMed

Cape, J N

1993-01-01

The concept of critical levels was developed in order to define short-term and long-term average concentrations of gaseous pollutants above which plants may be damaged. Although the usual way in which pollutants in precipitation (wet deposition) influence vegetation is by affecting soil processes, plant foliage exposed to fog and cloud, which often contain much greater concentrations of pollutant ions than rain, may be damaged directly. The idea of a critical level has been extended to define concentrations of pollutants in wet deposition above which direct damage to plants is likely. Concentrations of acidity and sulphate measured in mountain and coastal cloud are summarised. Vegetation at risk of injury is identified as montane forest growing close to the cloud base, where ion concentrations are highest. The direct effects of acidic precipitation on trees are reviewed, based on experimental exposure of plants to simulated acidic rain, fog or mist. Although most experiments have reported results in terms of pH (H(+) concentration), the accompanying anion is important, with sulphate being more damaging than nitrate. Both conifers and broadleaved tree seedlings showing subtle changes in the structural characteristics of leaf surfaces after exposure to mist or rain at or about pH 3.5, or sulphate concentration of 150 micromol litre(-1). Visible lesions on leaf surfaces occur at around pH 3 (500 micromol litre(-1) sulphate), broadleaved species tending to be more sensitive than conifers. Effects on photosynthesis and water relations, and interactions with other stresses (e.g. frost), have usually been observed only for treatments which have also caused visible injury to the leaf surface. Few experiments on the direct effects of polluted cloud have been conducted under field conditions with mature trees, which unlike seedlings in controlled conditions, may suffer a growth reduction in the absence of visible injury. Although leaching of cations (Ca(2+), Mg(2+), K(+)) is stimulated by acidic precipitation, amounts leached are small compared with root uptake, unless soils have been impoverished. This aspect of the potential effects of acidic precipitation is best considered in terms of the long-term critical-load of pollutants to the soil. Given the practical difficulties in monitoring cloud water composition, a method for defining critical levels is proposed, which uses climatological average data to identify the duration and frequency of hill cloud, and combines this information with measured or modelled concentrations of particulate sulphate in the atmosphere, to derive cloud water concentrations as a function of cloud liquid water content. For forests within 100 m of the cloud base the critical levels of particulate sulphate, corresponding to solution concentrations in the range 150-500 micromol litre(-1), are in the range 1-3.3 microg S m(-3). These concentrations are observed over much of central Europe, suggesting that many montane forests are at risk of direct effects of fossil-fuel-derived pollutants in cloud.

Martian "Swiss Cheese"

NASA Image and Video Library

2000-04-24

This image is illuminated by sunlight from the upper left. Looking like pieces of sliced and broken swiss cheese, the upper layer of the martian south polar residual cap has been eroded, leaving flat-topped mesas into which are set circular depressions such as those shown here. The circular features are depressions, not hills. The largest mesas here stand about 4 meters (13 feet) high and may be composed of frozen carbon dioxide and/or water. Nothing like this has ever been seen anywhere on Mars except within the south polar cap, leading to some speculation that these landforms may have something to do with the carbon dioxide thought to be frozen in the south polar region. On Earth, we know frozen carbon dioxide as "dry ice." On Mars, as this picture might be suggesting, there may be entire landforms larger than a small town and taller than 2 to 3 men and women that consist, in part, of dry ice. No one knows for certain whether frozen carbon dioxide has played a role in the creation of the "swiss cheese" and other bizarre landforms seen in this picture. The picture covers an area 3 x 9 kilometers (1.9 x 5.6 miles) near 85.6°S, 74.4°W at a resolution of 7.3 meters (24 feet) per pixel. This picture was taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during early southern spring on August 3, 1999. http://photojournal.jpl.nasa.gov/catalog/PIA02367

Geochemistry of Central Snake River Plain Basalts From Camas Prairie to Glenns Ferry, Southern Idaho

NASA Astrophysics Data System (ADS)

Vetter, S. K.; Johnston, S. A.; Shervais, J.; Hanan, B.

2006-12-01

The Snake River Plain (SRP) of southern Idaho represents the track of a hot-spot (mantle plume) which links voluminous flood basalts of the Miocene Columbia River province to Quaternary volcanic centers at Island Park and Yellowstone. However, much of the volcanism associated with this province either lies off the main volcanic trend or differs in age from the postulated plume passage. The Camas Prairie and the Mount Bennett Hills lie north of the Snake River-Yellowstone plume track, near the intersection of the eastern and western Snake River Plain trends. Young basalt flows cap highlands overlooking the Snake River near King Hill, but farther north in the Mount Bennett Hills and Camas Prairie these young lava flows are juxtaposed against older basalts along a series of WNW trending normal faults. These older basalt flows rest directly on rhyolite of the Mount Bennett Hills, making them the oldest basalts known in outcrop in this area. The older basalts in the Mount Bennett Hills include at least six major flows with a total thickness of 110 m. Although they have been strongly dissected by erosion, they still cover an outcrop area of 300 km2 . Eighty samples were collected as part of our petrologic survey of basaltic volcanism in the central Snake River Plain. These samples were studied petrographically and analyzed for their major elements, trace elements, and REE. The basalts consist of plagioclase and olivine microphenocrysts set in a groundmass of olivine, plagioclase, clinopyroxene, oxides and interstitial glass. The majority of samples have Mg# ranging from 50- 59. However there are samples that are more evolved as indicated by Mg# ranging from less than 50 to 29. The high Mg# samples have the following chemical ranges: TiO2 0.87 - 2.6 wt.%; FeO 9.95 - 13.7 wt.%; Nb 8 to 23 ppm; Zr 111 to 243 ppm; Ni 81 to 151 ppm; La 10.9 to 26.9 ppm. The more evolved samples have TiO2 1.4 3.93 wt.%; FeO 9.7 16.8 wt%; Nb 11 to 40 ppm; Zr 110 to 500 ppm; Ni 4 to 85 ppm; La 67 to 97 ppm. All magmas exhibit the typical SRP LREE enrichment. The high Mg# samples have La = 35 to 85x chondrite and Lu = 14 to 25x chondrite. The evolved samples have La = 200 to 300x chondrite and Lu = 30 to 40x chondrite. The high Mg# basalts resemble older off-axis basalts of the Boise River Group [Vetter and Shervais, 1992, JGR]. Rayleigh fractionation modeling of incompatible elements shows >80% olivine and plagioclase fractionation is needed to create the evolved magmas from the high Mg# basalts. Presents of these older basalts north of the main SRP trend maybe associated with the tilt of the plume as imaged by seismic tomography.

Volcanically-Triggered Rainfall and the Effect on Volcanological Hazards at Soufriere Hills, Montserrat

NASA Astrophysics Data System (ADS)

Poulidis, Alexandros-Panagiotis; Renfrew, Ian; Matthews, Adrian

2014-05-01

Atmospheric flow simulations over and around the Soufriere Hills volcano in the island of Montserrat in the Caribbean are studied, through a series of numerical model experiments, in order to link interactions between the volcano and the atmosphere. A heated surface is added on the top of the mountain, in order to simulate the dome of an active volcano that is not undergoing an eruption. A series of simulations with different atmospheric conditions and control parameters for the volcano will be presented. Simulations are made using the Weather Research and Forecasting (WRF) model, with a high resolution digital elevation map of Montserrat. Simulations with an idealised topography have also been examined, in order for the results to have general applicability to similar-sized volcanoes located in the Tropics. The model was initialised with soundings from representative days of qualitatively different atmospheric conditions from the rainy season. The heated volcanic dome changes the orographic flow response significantly, depending upon the atmospheric conditions and the magnitude of the dome surface temperature anomaly. The flow regime and qualitative characteristic features, such orographic clouds and rainfall patterns, can all change significantly. For example, the orographic rainfall over the volcano can be significantly enhanced with increased dome temperatures. The implications of these changes on the eruptive behaviour of the volcano and resulting secondary volcanic hazards, such as lahars, will be discussed.

Earth observations taken from shuttle orbiter Discovery during STS-82 mission

NASA Image and Video Library

1997-02-12

STS082-723-071 (11-21 Feb. 1997) --- The island of Hispaniola appears left center in this wide-angle view, photographed with a 70mm handheld camera from the Earth-orbiting Space Shuttle Discovery. The prominent cape is Cap-a-Foux, the northwest point of Haiti. The cloud is broken by the mountainous spine of the island. Smoke from bush fires appears in the valleys between the ridges. The coppery tinge of light reflected off the sea surface indicates pollution in the air -- probably industrial pollutants from North America which are typically fed around from the Atlantic seaboard into the Caribbean from the east.

TES premapping data: Slab ice and snow flurries in the Martian north polar night

USGS Publications Warehouse

Titus, T.N.; Kieffer, H.H.; Mullins, K.F.; Christensen, P.R.

2001-01-01

In the 1970s, Mariner and Viking spacecraft observations of the north polar region of Mars revealed polar brightness temperatures that were significantly below the expected kinetic temperatures for CO2 sublimation. For the past few decades, the scientific community has speculated as to the nature of these Martian polar cold spots. Thermal Emission Spectrometer (TES) thermal spectral data have shown these cold spots to result largely from fine-grained, CO2 and have constrained most of these cold spots to the surface (or near-surface). Cold spot formation is strongly dependent on topography, forming preferentially near craters and on polar slopes. TES data, combined with Mars Orbiter Laser Altimeter (MOLA) cloud data, suggest atmospheric condensates form a small fraction of the observed cold spots. TES observations of spectra close to a blackbody indicate that another major component of the polar cap is slab CO2 ice; these spectrally bland regions commonly have a low albedo. The cause is uncertain but may result from most of the light being reflected toward the specular direction, from the slab ice being intrinsically dark, or from it being transparent. Regions of the cap where the difference between the brightness temperatures at 18 ??m (T18) and 25 ??m (T25) is less than 5?? are taken to indicate deposits of slab ice. Slab ice is the dominant component of the polar cap at latitudes outside of the polar night. Copyright 2001 by the American Geophysical Union.

Venus 2004: east and west elongations and solar transit

NASA Astrophysics Data System (ADS)

McKim, R. J.; Blaxall, K.; Heath, A.

2007-04-01

The year 2004 was exceptional in producing the first solar transit of Venus since the late Victorian era. The bright aureole and atmospheric ring were re-observed, and the entire phenomenon was witnessed for the first time ever in hydrogen alpha light. Although routine observations throughout 2004 were unexceptional, patterns of visibility of bright and dark markings, cusp extensions and cusp-caps were recorded. No correlation was found between the latitude of the sub-Earth point and the visibility of either cusp-cap, with the S. cap predominating for most of the year. It was possible to accurately follow individual ultraviolet dark markings over many consecutive rotations, extending from the E. to W. elongations, and thereby to make a current measurement of the synodic atmospheric rotation period for the near-equatorial features: 3.996 ± 0.001 days. The true Ashen Light was reported visually on only a few occasions, but these correspond closely to times when infrared emission from the surface of the dark side was recorded in 1-micron waveband images. Some of the stable dark side albedo features were also visible upon the 1-micron images, and have been tentatively identified with known surface features. Infrared imaging at the same waveband showed little detail on the sunlit disk, but a few bright spots were sufficiently well observed to suggest a synodic rotation period close to 5.0 days, not atypical for the lower cloud decks.

Environmental Controls on Above-Ground Biomass in the Taita Hills, Kenya

NASA Astrophysics Data System (ADS)

Adhikari, H.; Heiskanen, J.; Siljander, M.; Maeda, E. E.; Heikinheimo, V.; Pellikka, P.

2016-12-01

Tropical forests are globally significant ecosystems which maintain high biodiversity and provide valuable ecosystem services, including carbon sink, climate change mitigation and adaptation. This ecosystem has been severely degraded for decades. However, the magnitude and spatial patterns of the above ground biomass (AGB) in the tropical forest-agriculture landscapes is highly variable, even under the same climatic condition and land use. This work aims 1) to generate wall-to-wall map of AGB density for the Taita Hills in Kenya based on field measurements and airborne laser scanning (ALS) and 2) to examine environmental controls on AGB using geospatial data sets on topography, soils, climate and land use, and statistical modelling. The study area (67000 ha) is located in the northernmost part of the Eastern Arc Mountains of Kenya and Tanzania, and the highest hilltops reach over 2200 m in elevation. Most of the forest area has been cleared for croplands and agroforestry, and hills are surrounded by the semi-arid scrublands and dry savannah at an elevation of 600-900 m a.s.l. As a result, the current land cover is a mosaic of various types of land cover and land use. The field measurements were carried out in total of 216 plots in 2013-2015 for AGB computations and ALS flights were conducted in 2014-2015. AGB map at 30 m x 30 m resolution was implemented using multiple linear regression based on ALS variables derived from the point cloud, namely canopy cover and 25 percentile height of ALS returns (R2 = 0.88). Boosted regression trees (BRT) was used for examining the relationship between AGB and explanatory variables, which were derived from ALS-based high resolution DEM (2 m resolution), soil database, downscaled climate data and land cover/use maps based on satellite image analysis. The results of these analyses will be presented in the conference.

Zimbabwe Culture before Mapungubwe: New Evidence from Mapela Hill, South-Western Zimbabwe

PubMed Central

Chirikure, Shadreck; Manyanga, Munyaradzi; Pollard, A. Mark; Bandama, Foreman; Mahachi, Godfrey; Pikirayi, Innocent

2014-01-01

Across the globe, the emergence of complex societies excites intense academic debate in archaeology and allied disciplines. Not surprisingly, in southern Africa the traditional assumption that the evolution of socio-political complexity began with ideological transformations from K2 to Mapungubwe between CE1200 and 1220 is clouded in controversy. It is believed that the K2−Mapungubwe transitions crystallised class distinction and sacred leadership, thought to be the key elements of the Zimbabwe culture on Mapungubwe Hill long before they emerged anywhere else. From Mapungubwe (CE1220–1290), the Zimbabwe culture was expressed at Great Zimbabwe (CE1300–1450) and eventually Khami (CE1450–1820). However, new fieldwork at Mapela Hill, when coupled with a Bayesian chronology, offers tremendous fresh insights which refute this orthodoxy. Firstly, Mapela possesses enormous prestige stone-walled terraces whose initial construction date from the 11th century CE, almost two hundred years earlier than Mapungubwe. Secondly, the basal levels of the Mapela terraces and hilltop contain élite solid dhaka (adobe) floors associated with K2 pottery and glass beads. Thirdly, with a hilltop and flat area occupation since the 11th century CE, Mapela exhibits evidence of class distinction and sacred leadership earlier than K2 and Mapungubwe, the supposed propagators of the Zimbabwe culture. Fourthly, Mapungubwe material culture only appeared later in the Mapela sequence and therefore post-dates the earliest appearance of stone walling and dhaka floors at the site. Since stone walls, dhaka floors and class distinction are the essence of the Zimbabwe culture, their earlier appearance at Mapela suggests that Mapungubwe can no longer be regarded as the sole cradle of the Zimbabwe culture. This demands not just fresh ways of accounting for the rise of socio-political complexity in southern Africa, but also significant adjustments to existing models. PMID:25360782

Zimbabwe culture before Mapungubwe: new evidence from Mapela Hill, South-Western Zimbabwe.

PubMed

Chirikure, Shadreck; Manyanga, Munyaradzi; Pollard, A Mark; Bandama, Foreman; Mahachi, Godfrey; Pikirayi, Innocent

2014-01-01

Across the globe, the emergence of complex societies excites intense academic debate in archaeology and allied disciplines. Not surprisingly, in southern Africa the traditional assumption that the evolution of socio-political complexity began with ideological transformations from K2 to Mapungubwe between CE1200 and 1220 is clouded in controversy. It is believed that the K2-Mapungubwe transitions crystallised class distinction and sacred leadership, thought to be the key elements of the Zimbabwe culture on Mapungubwe Hill long before they emerged anywhere else. From Mapungubwe (CE1220-1290), the Zimbabwe culture was expressed at Great Zimbabwe (CE1300-1450) and eventually Khami (CE1450-1820). However, new fieldwork at Mapela Hill, when coupled with a Bayesian chronology, offers tremendous fresh insights which refute this orthodoxy. Firstly, Mapela possesses enormous prestige stone-walled terraces whose initial construction date from the 11th century CE, almost two hundred years earlier than Mapungubwe. Secondly, the basal levels of the Mapela terraces and hilltop contain élite solid dhaka (adobe) floors associated with K2 pottery and glass beads. Thirdly, with a hilltop and flat area occupation since the 11th century CE, Mapela exhibits evidence of class distinction and sacred leadership earlier than K2 and Mapungubwe, the supposed propagators of the Zimbabwe culture. Fourthly, Mapungubwe material culture only appeared later in the Mapela sequence and therefore post-dates the earliest appearance of stone walling and dhaka floors at the site. Since stone walls, dhaka floors and class distinction are the essence of the Zimbabwe culture, their earlier appearance at Mapela suggests that Mapungubwe can no longer be regarded as the sole cradle of the Zimbabwe culture. This demands not just fresh ways of accounting for the rise of socio-political complexity in southern Africa, but also significant adjustments to existing models.

Earth Observations taken by the Expedition 17 Crew

NASA Image and Video Library

2008-08-04

ISS017-E-012583 (4 Aug. 2008) --- Cape Farewell, Greenland is featured in this image photographed by an Expedition 17 crewmember on the International Space Station (ISS). This view illustrates the southernmost tip of Greenland, known as Kap Farvel in Danish and Nunap Isua in Inuit. The viewing direction is towards the northeast; the image was taken when the space station was located near its most northerly orbital latitude of 52 degrees, off the northern coast of the Island of Newfoundland approximately 1160 kilometers to the southwest. Greenland is the world's largest island with an area of over 2 million square kilometers; however much of the island is covered by an ice cap that can reach thicknesses of 3 kilometers. The image is highly oblique -- taken from an angle looking outwards from the ISS, rather than straight down towards the Earth -- and this provides a sense of topography along the southern edge of Greenland. The exposed dark grey bedrock along the southwestern coastline has been carved by glaciers into numerous fjords -- steep-sided valleys that drain directly into the ocean; the white cloud cover surrounding the island doubtless contains some sea ice and icebergs calved from glaciers. A band of high-altitude cirrus clouds (light grey) cast shadows on the lower stratus cloud deck in the lower third of the image. The thin blue layer of Earth's atmosphere is visible.

Leveraging Cloud Technology to Provide a Responsive, Reliable and Scalable Backend for the Virtual Ice Sheet Laboratory Using the Ice Sheet System Model and Amazon's Elastic Compute Cloud

NASA Astrophysics Data System (ADS)

Perez, G. L.; Larour, E. Y.; Halkides, D. J.; Cheng, D. L. C.

2015-12-01

The Virtual Ice Sheet Laboratory(VISL) is a Cryosphere outreach effort byscientists at the Jet Propulsion Laboratory(JPL) in Pasadena, CA, Earth and SpaceResearch(ESR) in Seattle, WA, and the University of California at Irvine (UCI), with the goal of providing interactive lessons for K-12 and college level students,while conforming to STEM guidelines. At the core of VISL is the Ice Sheet System Model(ISSM), an open-source project developed jointlyat JPL and UCI whose main purpose is to model the evolution of the polar ice caps in Greenland and Antarctica. By using ISSM, VISL students have access tostate-of-the-art modeling software that is being used to conduct scientificresearch by users all over the world. However, providing this functionality isby no means simple. The modeling of ice sheets in response to sea and atmospheric temperatures, among many other possible parameters, requiressignificant computational resources. Furthermore, this service needs to beresponsive and capable of handling burst requests produced by classrooms ofstudents. Cloud computing providers represent a burgeoning industry. With majorinvestments by tech giants like Amazon, Google and Microsoft, it has never beeneasier or more affordable to deploy computational elements on-demand. This isexactly what VISL needs and ISSM is capable of. Moreover, this is a promisingalternative to investing in expensive and rapidly devaluing hardware.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

This image shows clouds and one of the many storm fronts common in the north polar region during spring and early summer. Note the linear nature of the clouds towards the top of the image, and the appearance of a large crater barely visible beneath the cloud cover.

Image information: VIS instrument. Latitude 86.5, Longitude 64.5 East (295.5 West). 40 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Antarctic lakes (above and beneath the ice sheet): Analogues for Mars

NASA Technical Reports Server (NTRS)

Rice, J. W., Jr.

1992-01-01

The perennial ice covered lakes of the Antarctic are considered to be excellent analogues to lakes that once existed on Mars. Field studies of ice covered lakes, paleolakes, and polar beaches were conducted in the Bunger Hills Oasis, Eastern Antarctica. These studies are extended to the Dry Valleys, Western Antarctica, and the Arctic. Important distinctions were made between ice covered and non-ice covered bodies of water in terms of the geomorphic signatures produced. The most notable landforms produced by ice covered lakes are ice shoved ridges. These features form discrete segmented ramparts of boulders and sediments pushed up along the shores of lakes and/or seas. Sub-ice lakes have been discovered under the Antarctic ice sheet using radio echo sounding. These lakes occur in regions of low surface slope, low surface accumulations, and low ice velocity, and occupy bedrock hollows. The presence of sub-ice lakes below the Martian polar caps is possible. The discovery of the Antarctic sub-ice lakes raises possibilities concerning Martian lakes and exobiology.

Temperature Dependence in Homogeneous and Heterogeneous Nucleation

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGraw R. L.; Winkler, P. M.; Wagner, P. E.

2017-08-01

Heterogeneous nucleation on stable (sub-2 nm) nuclei aids the formation of atmospheric cloud condensation nuclei (CCN) by circumventing or reducing vapor pressure barriers that would otherwise limit condensation and new particle growth. Aerosol and cloud formation depend largely on the interaction between a condensing liquid and the nucleating site. A new paper published this year reports the first direct experimental determination of contact angles as well as contact line curvature and other geometric properties of a spherical cap nucleus at nanometer scale using measurements from the Vienna Size Analyzing Nucleus Counter (SANC) (Winkler et al., 2016). For water nucleating heterogeneouslymore » on silver oxide nanoparticles we find contact angles around 15 degrees compared to around 90 degrees for the macroscopically measured equilibrium angle for water on bulk silver. The small microscopic contact angles can be attributed via the generalized Young equation to a negative line tension that becomes increasingly dominant with increasing curvature of the contact line. These results enable a consistent theoretical description of heterogeneous nucleation and provide firm insight to the wetting of nanosized objects.« less

The So-Called 'Face on Mars'

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 13 April 2002) The Science The so called 'Face on Mars' can be seen slightly above center and to the right in this THEMIS visible image. This 3-km long knob, located near 10o N, 40o W (320o E), was first imaged by the Viking spacecraft in the 1970's and was seen by some to resemble a face carved into the rocks of Mars. Since that time the Mars Orbiter Camera on the Mars Global Surveyor spacecraft has provided detailed views of this hill that clearly show that it is a normal geologic feature with slopes and ridges carved by eons of wind and downslope motion due to gravity. A similar-size hill in Phoenix, Arizona resembles a camel lying on the ground, and Phoenicians whimsically refer to it as Camelback Mountain. Like the hills and knobs of Mars, however, Camelback Mountain was carved into its unusual shape by thousands of years of erosion. The THEMIS image provides a broad perspective of the landscape in this region, showing numerous knobs and hills that have been eroded into a remarkable array of different shapes. Many of these knobs, including the 'Face', have several flat ledges partway up the hill slopes. These ledges are made of more resistant layers of rock and are the last remnants of layers that once were continuous across this entire region. Erosion has completely removed these layers in most places, leaving behind only the small isolated hills and knobs seen today. Many of the hills and ridges in this area also show unusual deposits of material that occur preferentially on the cold, north-facing slopes. It has been suggested that these deposits were 'pasted' on the slopes, with the distinct, rounded boundary on their upslope edges being the highest remaining point of this pasted-on layer. In several locations, such as in the large knob directly south of the 'Face', these deposits occur at several different heights on the hill. This observation suggests the layer once draped the entire knob and has since been removed from all but the north-facing slopes. The presence of water ice in these layers is a likely possibility to account for their preservation only on the colder surfaces. Alternatively, these unique features could be the result of the slow downslope motion of the surface layer, possibly enhanced by the presence of ground ice. One argument against downslope motion is the observation that the uppermost rounded boundary of these layers typically occurs at approximately the same distance below the ridge crest. This would suggest the (seemingly) unlikely possibility that all of these layers had moved downslope the same amount regardless of where they are located. In either case, ground ice likely plays an important role in the formation and preservation of these deposits because they only occur on the cold slopes facing away from the Sun where ground ice is more stable and may still be present today. The Story Nature is an imaginative artist, creating all kinds of wonderful landforms, cloud shapes, and other patterned features that remind people of familiar things in our lives. We see a 'man in the moon' when it is full in the night sky, and dream of a dromedary-dotted desert when coming upon Arizona's Camelback Mountain or Colorado's 'Kissing Camels' in the 'Garden of the Gods.' Near Ludlow, California, a lonely prospector once noticed that the appealing outline of the mountains resembled a reclining woman, and named the place Sleeping Beauty. And this naming delight isn't limited to Earth. The Mars Pathfinder mission team couldn't help but name the rocks at the landing site, including a bear-headed-looking one named Yogi. Part of the fun of exploration is not just visiting a strange world, but relating to it in human terms. On Mars, we've already seen a valentine heart-shaped crater, a happy-faced crater, and even a murky and mysterious 'face' on Mars. This face (seen here about halfway down the image and to the right) is really just a hill with slopes and ridges that are shadowed in a way that can sometimes resemble a face from far away. The first picture of this area was taken by the Viking spacecraft in the 1970s, and people have been intrigued ever since. However, orbiter camera technologies have actually become so good in providing a clear view of the hill that it's almost a disappointment to see how normal an eroded hill this well-liked feature is. Well, disappointing unless you're a geologist, that is! This whole area is, in fact, a geologist's dream. Erosion has been Nature's sculptor throughout the area, and all kinds of remarkably shaped knobs and hills speckle the region. While their shapes are fun to contemplate, it's no mystery to geologists how they formed. Several flat ledges part way up the slopes of these hills are made of layers of rock that stand strong against erosion's relentless carving. Less resistant layers in the region have eroded away completely in most places, leaving behind only the small, isolated hills and knobs we see today. Don?t think everything in this scene is easily understandable, however. What captures the attention of scientists is a bunch of unusual deposits of material on the cold, north-facing slopes of the hills. Did Nature mix some Martian dirt and ice from the planet's 'pallet,' and then 'paste' on a slightly cemented deposit over the northern slopes? Or did an upper layer of material slowly creep downslope over time, carried by the movement of ice? Ground ice, in this case, has probably been more of a preserver than an eroder, keeping a record of the formation and existence of these deposits over time. Geologists are grateful for that peek into the Martian past and the chance to study it in-depth.

Diversity and biogeography of land snails (Mollusca, Gastropoda) in the limestone hills of Perak, Peninsular Malaysia

PubMed Central

Foon, Junn Kitt; Clements, Gopalasamy Reuben; Liew, Thor-Seng

2017-01-01

Abstract Limestone hills are now gaining global conservation attention as hotspots for short-range endemic species. Levels of land snail endemism can be high at limestone hills, especially at hill clusters that are geographically isolated. In the State of Perak, Peninsular Malaysia, limestone hills have been opportunistically surveyed for land snails in the past, but the majority have yet to be surveyed. To address this knowledge gap, we systematically surveyed the terrestrial malacofauna of 12 limestone hills that, based on our opinion, are a representation of the limestone land snail assemblages within the State. Our inventory yielded high sampling completeness (>85%). We found 122 species of land snails, of which 34 species were unique to one of the surveyed hills. We identified 30 species that are potentially new to science. The number of land snail species recorded at each hill ranged between 39 and 63 species. Four of the sampled limestone hills namely, Prk 01 G. Tempurung, Prk 55 G. Pondok, Prk 47 Kanthan, and Prk 64 Bt Kepala Gajah, have high levels of species richness and unique species, representing 91% of the total species recorded in this study. We identified two clusters of limestone hills in central Perak with distinct differences in land snail species composition – a northern hill cluster on elevated granite bedrock and southern hill cluster in a low-lying valley surrounded by alluvial soils. As limestone hills continue to be quarried to meet the cement demand, the four identified limestone hills, along with other hills from the two clusters, warrant urgent conservation attention in order to maintain high species diversity within Perak’s terrestrial malacofauna. PMID:28769723

On the Electrification of Pyrocumulus Clouds

NASA Technical Reports Server (NTRS)

Lang, Timothy J.; Rutledge, Steven A.; Dolan, Brenda; Krehbiel, Paul; Rison, William; Lindsey, Daniel T.

2013-01-01

The electrification (or lack thereof) of pyrocumulus clouds is examined for several different wildfires that occurred during 2012-2013. For example, pyrocumulus clouds above three Colorado wildfires (Hewlett Gulch, High Park, and Waldo Canyon; all occurred during summer 2012) electrified and produced small intracloud discharges whenever the smoke plumes grew to high altitudes (over 10 km above mean sea level, or MSL). This occurred during periods of rapid wildfire growth, as indicated by the shortwave infrared channel on a geostationary satellite, as well as by incident reports. In the Hewlett Gulch case, the fire growth led to increased updrafts within the plume, as inferred by multiple-Doppler radar syntheses, which led to the vertical development and subsequent electrification - a life cycle as short as 30 minutes. The lightning, detected by a three-dimensional lightning mapping network, was favored in high-altitude regions (10 km MSL) containing modest reflectivities (25 dBZ and lower), 0 dB differential reflectivity, and reduced correlation coefficient (0.6-0.7). This indicated the likely presence of ice particles (crystals and aggregates, possibly rimed) mixed with ash. Though neither multiple-Doppler nor polarimetric observations were available during the electrification of the High Park and Waldo Canyon plumes, their NEXRAD observations showed reflectivity structures consistent with Hewlett Gulch. In addition, polarimetric and multiple-Doppler scanning of unelectrified High Park plumes indicated only irregularly shaped ash, and not ice, was present (i.e., reflectivities < 25 dBZ, differential reflectivity > 5 dB, correlation < 0.4), and there was no broaching of the 10 km altitude. Based on these results, the electrification likely was caused by ice-based processes that did not involve significant amounts of graupel. Results for pyrocumulus clouds above notable 2013 wildfires that also experienced rapid growth (e.g., Black Forest, Yarnell Hill, West Fork, Tres Lagunas, etc.) will be compared against the 2012 cases, with special emphasis on polarimetric NEXRAD and available lightning measurements, in order to better understand the physical processes responsible for pyrocumulus electrification.

An experimental investigation of hollow cathode-based plasma contactors. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Williams, John D.

1991-01-01

Experimental results are presented which describe operation of the plasma environment associated with a hollow cathod-based plasma contactor collecting electrons from or emitting them to an ambient, low density Maxwellian plasma. A one-dimensional, phenomenological model of the near-field electron collection process, which was formulated from experimental observations, is presented. It considers three regions, namely, a plasma cloud adjacent to the contactor, an ambient plasma from which electrons are collected, and a double layer region that develops between the contactor plasma cloud and the ambient plasma regions. Results of the electron emission experiments are also presented. An important observation is made using a retarding potential analyzer (RPA) which shows that high energy ions generally stream from a contactor along with the electrons being emitted. A mechanism for this phenomenon is presented and it involves a high rate of ionization induced between electrons and atoms flowing together from the hollow cathode orifice. This can result in the development of a region of high positive potential. Langmuir and RPA probe data suggest that both electrons and ions expand spherically from this hill region. In addition to experimental observations, a one-dimensional model which describes the electron emission process and predicts the phenomena just mentioned is presented and shown to agree qualitatively with these observations.

Fires in Myanmar (2007)

NASA Technical Reports Server (NTRS)

2007-01-01

In Southeast Asia, fires are common and widespread throughout the dry season, which roughly spans the northern hemisphere winter months. People set fires to clear crop stubble and brush and to prepare grazing land for a new flush of growth when the rainy season arrives. These intentional fires are too frequently accompanied by accidental fires that invade nearby forests and woodlands. The combination of fires produces a thick haze that alternately lingers and disperses, depending on the weather. This image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite shows fire activity on March 19, 2007, across eastern India, Myanmar, Thailand, Laos, and China. Places where MODIS detected actively burning fires are marked in red on the image. The darker green areas are generally more wooded areas or forests, while the paler green and tan areas are agricultural land. Smoke pools over low-lying areas of the hilly terrain in gray pockets. The green tops of rolling hills in Thailand emerge from a cloud of low-lying smoke. According to news reports from Thailand, the smoke blanket created air quality conditions that were considered unhealthy for all groups, and it prompted the Thai Air Force to undertake cloud-seeding attempts in an effort to cleanse the skies with rain. Commercial air traffic was halted due to poor visibility.

Aerosol nucleation and growth in the TTL, due to tropical convection, during the ACTIVE campaign

NASA Astrophysics Data System (ADS)

Waddicor, D.; Vaughan, G.; Choularton, T.

2009-04-01

The Aerosol and Chemical Transport In tropical convection (ACTIVE) campaign took place between October 2005 and February 2006. This investigation involved the sampling of deep convective storms that occur in the Tropics; the campaign was based in Darwin, Northern Territory, Australia - the latter half of the campaign coincided with the monsoon season. A range of scientific equipment was used to sample the inflow and outflow air from these storms; of particular importance were the NERC Dornier (low-level) and ARA Egrett (high-level outflow) aircraft. The Dornier held a range of aerosol, particle and chemical detectors for the purpose of analysing the planetary boundary layer (PBL), in the vicinity of tropical convection. The Egrett contained detection instrumentation for a range of sizes of aerosol and cloud particles (2 Condensation Particle Counters (CPC), CAPS, CIP, CPI) in the storm outflow. This allowed a quantifiable measurement to be made of the effect of deep tropical convection on the aerosol population in the Tropical Tropopause Layer (TTL). The ACTIVE campaign found that there were large numbers of aerosol particles in the 10 - 100 nm (up to 25,000 /cm3 STP) and 100 - 1000 nm (up to 600 /cm3) size ranges. These values, in many instances, surpassed those found in the PBL. The higher levels of aerosol found in the TTL compared to the PBL could indicate that aerosol nucleation was occurring in the TTL as a direct result of convective activity. Furthermore, the Egrett aircraft found distinct boundaries between the high levels of aerosol, which were found in cloud free regions, and very low numbers of aerosol, which were found in the cloudy regions (storm anvil). The air masses were determined, from back trajectories, to have been through convective uplift and were formerly part of the anvil cloud. The cloudy regions would have contained high levels of entrapped precursor gases. Reduced nucleation and cloud particle scavenging of aerosol and gases would give a much reduced aerosol number concentration in cloud. The high aerosol (cloud free) areas would appear after the cloud began to evaporate through the process of aerosol nucleation. The evaporating cloud particles and reduced cloud surface area would allow aerosol nucleation to occur - typically involving sulphuric acid and water, released from ice crystals. The time scales for the particle production have also been investigated using satellite and wind projections/ECMWF back trajectories.

Four Views of Mars in Northern Summer

NASA Technical Reports Server (NTRS)

1997-01-01

Four faces of Mars as seen on March 30, 1997 are presented in this montage of NASA Hubble Space Telescope images. Proceeding in the order upper-left, upper-right, lower-left, lower-right, Mars has rotated about ninety degrees between each successive time step. For example the Tharsis volcanoes, which are seen (between 7:30 and 9 o'clock positions) in mid-morning in the UPPER-RIGHT view, are seen near the late afternoon edge of the planet (about 3 o'clock position) in the lower-left image. All of these color images are composed of individual red (673 nanometers), green (502 nm), and blue (410 nm) Planetary Camera exposures.

Upper left: This view is centered on Ares Valles, where Pathfinder will land on July 4, 1997; the Valles Marineris canyon system stretches to the west across the lower left portion of the planet, while the bright, orangish desert of Arabia Planitia is to the east. The bright polar water-ice cap, surrounded by a dark ring of sand dunes, is obvious in the north; since it is northern summer and the pole is tilted toward us, the residual north polar cap is seen in its entirety in all four images. Acidalia Planitia, the prominent dark area fanning southward from the polar region, is thought to have a surface covered with dark sand. Numerous 'dark wind streaks' are visible to the south of Acidalia, resulting from wind-blown sand streaming out of the interiors of craters.

Upper right: The Tharsis volcanos and associated clouds are prominent in the western half of this view. Olympus Mons, spanning 340 miles (550 km) across its base and reaching an elevation of 16 miles (25 km), extends through the cloud deck near the western limb, while (from the south) Arsia Mons, Pavonis Mons, and Ascraeus Mons are to the west of center. Valles Marineris stretches to the east, and the Pathfinder landing site is shrouded in clouds near the afternoon limb.

Lower left: This relatively featureless sector of Mars stretches from the Elysium volcanic region in the west to the Tharsis volcanoes (shrouded by the bright clouds near the afternoon limb) in the east. The group of three dark specks just left of center are all that remain of Cerberus, a very prominent dark region during the Viking and Mariner 9 missions. This is an example of the remarkable large scale changes which can occur on Mars due to windblown dust: the former dark area has now been covered by a layer of bright dust, masking the underlying material.

Lower right: The dark Syrtis Major region dominates this image. Syrtis Major is one of the most prominent dark features on Mars, and has been visible since ground-based observers first peered at Mars through telescopes. The bright cloud at 3 o'clock is associated with Elysium Mons. The bright bluish-white feature near the southern limb of the planet is Hellas, a 1,200 mile (2,000 km) diameter impact basin formed by the collision of a large body with Mars long ago. Hellas is covered with dry ice frost and clouds during this season (winter in the south).

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

The Summertime Arctic Atmosphere: Meteorological Measurements during the Arctic Ocean Experiment 2001.

NASA Astrophysics Data System (ADS)

Tjernström, Michael; Leck, Caroline; Persson, P. Ola G.; Jensen, Michael L.; Oncley, Steven P.; Targino, Admir

2004-09-01

An atmospheric boundary layer experiment into the high Arctic was carried out on the Swedish ice-breaker Oden during the summer of 2001, with the primary boundary layer observations obtained while the icebreaker drifted with the ice near 89°N during 3 weeks in August. The purposes of the experiment were to gain an understanding of atmospheric boundary layer structure and transient mixing mechanisms, in addition to their relationships to boundary layer clouds and aerosol production. Using a combination of in situ and remote sensing instruments, with temporal and spatial resolutions previously not deployed in the Arctic, continuous measurements of the lower-troposphere structure and boundary layer turbulence were taken concurrently with atmospheric gas and particulate chemistry, and marine biology measurements.The boundary layer was strongly controlled by ice thermodynamics and local turbulent mixing. Near-surface temperatures mostly remained between near the melting points of the sea- and freshwater, and near-surface relative humidity was high. Low clouds prevailed and fog appeared frequently. Visibility outside of fog was surprisingly good even with very low clouds, probably due to a lack of aerosol particles preventing the formation of haze. The boundary layer was shallow but remained well mixed, capped by an occasionally very strong inversion. Specific humidity often increased with height across the capping inversion.In contrast to the boundary layer, the free troposphere often retained its characteristics from well beyond the Arctic. Elevated intrusions of warm, moist air from open seas to the south were frequent. The picture that the Arctic atmosphere is less affected by transport from lower latitudes in summer than the winter may, thus, be an artifact of analyzing only surface measurements. The transport of air from lower latitudes at heights above the boundary layer has a major impact on the Arctic boundary layer, even very close to the North Pole. During a few week-long periods synoptic-scale weather systems appeared, while weaker and shallower mesoscale fronts were frequent. While frontal passages changed the properties of the free troposphere, changes in the boundary layer were more determined by local effects that often led to changes contrary to those aloft. For example, increasing winds associated with a cold front often led to a warming of the near-surface air by mixing and entrainment.

Geospatial Method for Computing Supplemental Multi-Decadal U.S. Coastal Land-Use and Land-Cover Classification Products, Using Landsat Data and C-CAP Products

NASA Technical Reports Server (NTRS)

Spruce, J. P.; Smoot, James; Ellis, Jean; Hilbert, Kent; Swann, Roberta

2012-01-01

This paper discusses the development and implementation of a geospatial data processing method and multi-decadal Landsat time series for computing general coastal U.S. land-use and land-cover (LULC) classifications and change products consisting of seven classes (water, barren, upland herbaceous, non-woody wetland, woody upland, woody wetland, and urban). Use of this approach extends the observational period of the NOAA-generated Coastal Change and Analysis Program (C-CAP) products by almost two decades, assuming the availability of one cloud free Landsat scene from any season for each targeted year. The Mobile Bay region in Alabama was used as a study area to develop, demonstrate, and validate the method that was applied to derive LULC products for nine dates at approximate five year intervals across a 34-year time span, using single dates of data for each classification in which forests were either leaf-on, leaf-off, or mixed senescent conditions. Classifications were computed and refined using decision rules in conjunction with unsupervised classification of Landsat data and C-CAP value-added products. Each classification's overall accuracy was assessed by comparing stratified random locations to available reference data, including higher spatial resolution satellite and aerial imagery, field survey data, and raw Landsat RGBs. Overall classification accuracies ranged from 83 to 91% with overall Kappa statistics ranging from 0.78 to 0.89. The accuracies are comparable to those from similar, generalized LULC products derived from C-CAP data. The Landsat MSS-based LULC product accuracies are similar to those from Landsat TM or ETM+ data. Accurate classifications were computed for all nine dates, yielding effective results regardless of season. This classification method yielded products that were used to compute LULC change products via additive GIS overlay techniques.

Coupling sky images with radiative transfer models: a new method to estimate cloud optical depth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mejia, Felipe A.; Kurtz, Ben; Murray, Keenan

A method for retrieving cloud optical depth ( τ c) using a UCSD developed ground-based sky imager (USI) is presented. The radiance red–blue ratio (RRBR) method is motivated from the analysis of simulated images of various τ c produced by a radiative transfer model (RTM). From these images the basic parameters affecting the radiance and red–blue ratio (RBR) of a pixel are identified as the solar zenith angle ( θ 0), τ c, solar pixel angle/scattering angle ( θ s), and pixel zenith angle/view angle ( θ z). The effects of these parameters are described and the functions for radiance,more » I λ τ c, θ 0, θ s, θ z , and RBR τ c, θ 0, θ s, θ z are retrieved from the RTM results. RBR, which is commonly used for cloud detection in sky images, provides non-unique solutions for τ c, where RBR increases with τ c up to about τ c = 1 (depending on other parameters) and then decreases. Therefore, the RRBR algorithm uses the measured I λ meas θ s, θ z , in addition to RBR meas θ s, θ z , to obtain a unique solution for τ c. The RRBR method is applied to images of liquid water clouds taken by a USI at the Oklahoma Atmospheric Radiation Measurement (ARM) program site over the course of 220 days and compared against measurements from a microwave radiometer (MWR) and output from the Min et al. (2003) method for overcast skies. τ c values ranged from 0 to 80 with values over 80, being capped and registered as 80. A τ c RMSE of 2.5 between the Min et al. (2003) method and the USI are observed. The MWR and USI  have an RMSE of 2.2, which is well within the uncertainty of the MWR. In conclusion, the procedure developed here provides a foundation to test and develop other cloud detection algorithms.« less

Coupling sky images with radiative transfer models: a new method to estimate cloud optical depth

DOE PAGES

Mejia, Felipe A.; Kurtz, Ben; Murray, Keenan; ...

2016-08-30

A method for retrieving cloud optical depth ( τ c) using a UCSD developed ground-based sky imager (USI) is presented. The radiance red–blue ratio (RRBR) method is motivated from the analysis of simulated images of various τ c produced by a radiative transfer model (RTM). From these images the basic parameters affecting the radiance and red–blue ratio (RBR) of a pixel are identified as the solar zenith angle ( θ 0), τ c, solar pixel angle/scattering angle ( θ s), and pixel zenith angle/view angle ( θ z). The effects of these parameters are described and the functions for radiance,more » I λ τ c, θ 0, θ s, θ z , and RBR τ c, θ 0, θ s, θ z are retrieved from the RTM results. RBR, which is commonly used for cloud detection in sky images, provides non-unique solutions for τ c, where RBR increases with τ c up to about τ c = 1 (depending on other parameters) and then decreases. Therefore, the RRBR algorithm uses the measured I λ meas θ s, θ z , in addition to RBR meas θ s, θ z , to obtain a unique solution for τ c. The RRBR method is applied to images of liquid water clouds taken by a USI at the Oklahoma Atmospheric Radiation Measurement (ARM) program site over the course of 220 days and compared against measurements from a microwave radiometer (MWR) and output from the Min et al. (2003) method for overcast skies. τ c values ranged from 0 to 80 with values over 80, being capped and registered as 80. A τ c RMSE of 2.5 between the Min et al. (2003) method and the USI are observed. The MWR and USI  have an RMSE of 2.2, which is well within the uncertainty of the MWR. In conclusion, the procedure developed here provides a foundation to test and develop other cloud detection algorithms.« less

Hubble Watches the Red Planet as Mars Global Surveyor Begins Aerobraking

NASA Technical Reports Server (NTRS)

1997-01-01

[RIGHT] This NASA Hubble Space Telescope picture of Mars was taken on Sept. 12, one day after the arrival of the Mars Global Surveyor (MGS) spacecraft and only five hours before the beginning of autumn in the Martian northern hemisphere. (Mars is tilted on its axis like Earth, so it has similar seasonal changes, including an autumnal equinox when the Sun crosses Mars' equator from the northern to the southern hemisphere).

This Hubble picture was taken in support of the MGS mission. Hubble is monitoring the Martian weather conditions during the early phases of MGS aerobraking; in particular, the detection of large dust storms are important inputs into the atmospheric models used by the MGS mission to plan aerobraking operations.

Though a dusty haze fills the giant Hellas impact basin south of the dark fin-shaped feature Syrtis Major, the dust appears to be localized within Hellas. Unless the region covered expands significantly, the dust will not be of concern for MGS aerobraking.

Other early signs of seasonal transitions on Mars are apparent in the Hubble picture. The northern polar ice cap is blanketed under a polar hood of clouds that typically start forming in late northern summer. As fall progresses, sunlight will dwindle in the north polar region and the seasonal polar cap of frozen carbon dioxide will start condensing onto the surface under these clouds.

Hubble observations will continue until October 13, as MGS carefully uses the drag of the Martian atmosphere to circularize its orbit about the Red Planet. After mid-October, Mars will be too close to the Sun, in angular separation, for Hubble to safely view.

The image is a composite of three separately filtered colored images taken with the Wide Field Planetary Camera 2 (WFPC2). Resolution is 35 miles (57 kilometers) per pixel (picture element). The Pathfinder landing site near Ares Valles is about 2200 miles (3600 kilometers) west of the center of this image, so was not visible during this observation. Mars was 158 million miles (255 million kilometers) from Earth at the time.

[LEFT]

An image of this region of Mars, taken in June 1997, is shown for comparison. The Hellas basin is filled with bright clouds and/or surface frost. More water ice clouds are visible across the planet than in the Sept. image, reflecting the effects of the changing season. Mars appears larger because it was 44 million miles (77 million kilometers) closer to Earth than in the September image.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

KSC-99pc05

NASA Image and Video Library

1999-01-03

KENNEDY SPACE CENTER, FLA. -- Amid clouds of exhaust, a Boeing Delta II expendable launch vehicle with NASA's Mars Polar Lander clears Launch Complex 17B, Cape Canaveral Air Station, after launch at 3:21:10 p.m. EST. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

KSC-99pc03

NASA Image and Video Library

1999-01-03

KENNEDY SPACE CENTER, FLA. -- A Boeing Delta II expendable launch vehicle lifts off with NASA's Mars Polar Lander into a cloud-covered sky at 3:21:10 p.m. EST from Launch Complex 17B, Cape Canaveral Air Station. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

Mushroom speleothems: Stromatolites that formed in the absence of phototrophs

NASA Astrophysics Data System (ADS)

Bontognali, Tomaso; D'Angeli, Ilenia; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano; Gonzales, Esteban; DeWaele, Jo

2016-04-01

Unusual speleothems resembling giant mushrooms occur in Santa Catalina Cave, Cuba. Although these mineral buildups are considered a natural heritage, their composition and formation mechanism remain poorly understood. Here we characterize their morphology and mineralogy and present a model for their genesis. We propose that the mushrooms, which are mainly comprised of calcite and aragonite, formed during four different phases within an evolving cave environment. The stipe of the mushroom is an assemblage of three well-known speleothems: a stalagmite surrounded by calcite rafts that were subsequently encrusted by cave clouds (mammilaries). More peculiar is the cap of the mushroom, which is morphologically similar to cerebroid stromatolites and thrombolites of microbial origin occurring in marine environments. Scanning electron microscopy investigations of this last unit revealed the presence of fossilized extracellular polymeric substances (EPS) - the constituents of biofilms and microbial mats. These organic microstructures are mineralized with Ca-carbonate, suggesting that the mushroom cap formed through a microbially-influenced mineralization process. The existence of cerebroid Ca-carbonate buildups forming in dark caves (i.e., in the absence of phototrophs) has interesting implications for the study of fossil microbialites preserved in ancient rocks, which are today considered as one of the earliest evidence for life on Earth.

Erosion rates and landscape evolution of the lowlands of the Upper Paraguay river basin (Brazil) from cosmogenic 10Be

NASA Astrophysics Data System (ADS)

Pupim, Fabiano do Nascimento; Bierman, Paul R.; Assine, Mario Luis; Rood, Dylan H.; Silva, Aguinaldo; Merino, Eder Renato

2015-04-01

The importance of Earth's low sloping areas in regard to global erosion and sediment fluxes has been widely and vigorously debated. It is a crucial area of research to elucidate geologically meaningful rates of land-surface change and thus the speed of element cycling on Earth. However, there are large portions of Earth where erosion rates have not been well or extensively measured, for example, the tropical lowlands. The Cuiabana lowlands are an extensive low-altitude and low-relief dissected metamorphic terrain situated in the Upper Paraguay river basin, central-west Brazil. Besides exposures of highly variable dissected metamorphic rocks, flat residual lateritic caps related to a Late Cenozoic planation surface dominate interfluves of the Cuiabana lowlands. The timescale over which the lowlands evolved and the planation surface developed, and the rate at which they have been modified by erosion, are poorly known. Here, we present measurements of in situ produced cosmogenic 10Be in outcropping metamorphic bedrock and clastic-lateritic caps to quantify rates of erosion of the surface and associated landforms in order to better understand the Quaternary landscape evolution of these lowlands. Overall, slow erosion rates (mean 10 m/Ma) suggest a stable tectonic environment in these lowlands. Erosion rates vary widely between different lithologies (range 0.57 to 28.3 m/Ma) consistent with differential erosion driving regional landform evolution. The lowest erosion rates are associated with the low-relief area (irregular plains), where clastic-laterite (mean 0.67 m/Ma) and quartzite (mean 2.6 m/Ma) crop out, whereas the highest erosion rates are associated with dissection of residual hills, dominated by metasandstone (mean 11.6 m/Ma) and phyllite (mean 27.6 m/Ma). These data imply that the Cuiabana lowland is comprised of two dominant landform sets with distinct and different dynamics. Because the planation surface (mostly lowlands) is lowering and losing mass more slowly than associated residual hills, regional relief is decreasing over time and the landscape is not in steady state. The extremely slow erosion rates of the clastic-laterite are similar to the slowest outcrop erosion rates reported worldwide. These slow rates are due to the material's properties and resistance, being comprised of quartzite fragments cemented by an iron-rich crust, and reflecting long-term weathering with iron chemical precipitation and ferricrete formation, at least since the Middle Pleistocene. The lateritic caprock appears to be a key factor maintaining hilltop summits of the planation surface over long timescales.

Results from the Mars global surveyor thermal emission spectrometer

USGS Publications Warehouse

Christensen, P.R.; Anderson, D.L.; Chase, S.C.; Clancy, R.T.; Clark, R.N.; Conrath, B.J.; Kieffer, H.H.; Kuzmin, R.O.; Malin, M.C.; Pearl, J.C.; Roush, T.L.; Smith, M.D.

1998-01-01

The Thermal Emission Spectrometer spectra of low albedo surface materials suggests that a four to one mixture of pyroxene to plagioclase, together with about a 35 percent dust component provides the best fit to the spectrum. Qualitative upper limits can be placed on the concentration of carbonates (<10 percent), olivine (<10 percent), clay minerals (<20 percent), and quartz (<5 percent) in the limited regions observed. Limb observations in the northern hemisphere reveal low-lying dust hazes and detached water-ice clouds at altitudes up to 55 kilometers. At an aerocentric longitude of 224??a major dust storm developed in the Noachis Terra region. The south polar cap retreat was similar to that observed by Viking.

South Polar 'Poodle'

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-422, 15 July 2003

Have you ever stared up at the clouds in the sky and seen the shapes of animals, people, or objects? Sometimes when the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) team is looking at newly-returned pictures from Mars, the same thing happens. This is a picture of pits and scarps in the frozen south polar carbon dioxide ice cap. Sunlight illuminates the scene from the upper right. At the bottom of the picture is a feature that resembles a long, thin poodle; its head faces to the left, the tail to the right. This picture is located near 86.9oS, 55.8oW.

Possible significance of cubic water-ice, H2O-Ic, in the atmospheric water cycle of Mars

NASA Technical Reports Server (NTRS)

Gooding, James L.

1988-01-01

The possible formation and potential significance of the cubic ice polymorph on Mars is discussed. When water-ice crystallizes on Earth, the ambient conditions of temperature and pressure result in the formation of the hexagonal ice polymorph; however, on Mars, the much lower termperature and pressures may permit the crystallization of the cubic polymorph. Cubic ice has two properties of possible importance on Mars: it is an excellant nucleator of other volatiles (such as CO2), and it undergoes an exothermic transition to hexagonal ice at temperatures above 170 K. These properties may have significant implications for both martian cloud formation and the development of the seasonal polar caps.

On the origin of Hill's causal criteria.

PubMed

Morabia, A

1991-09-01

The rules to assess causation formulated by the eighteenth century Scottish philosopher David Hume are compared to Sir Austin Bradford Hill's causal criteria. The strength of the analogy between Hume's rules and Hill's causal criteria suggests that, irrespective of whether Hume's work was known to Hill or Hill's predecessors, Hume's thinking expresses a point of view still widely shared by contemporary epidemiologists. The lack of systematic experimental proof to causal inferences in epidemiology may explain the analogy of Hume's and Hill's, as opposed to Popper's, logic.

Report on water supply for the proposed Southwestern Reformatory at El Reno, Oklahoma

USGS Publications Warehouse

Turner, S.F.

1931-01-01

The investigation on which this report is based was made in response to a request from the Bureau of Prisons, United States Department of Justice, for advice in regard to the development of a water supply for the proposed Southwestern Reformatory on the Fort Reno Military Reservation, 2 miles west of El Reno, Oklahoma. The tract set aside for the reformatory includes sec. 12 and the eastern half of sec. 11, T. 12 N, R. 8 W., and is about 1,000 acres in area. The proposed building site is in the north-central part of sec. 12, on a flat-topped hill just north of well No. 69. (See Plate 1.) It is understood that a maximum of 1,200 inmates is contemplated for this reformatory and that a water supply of about 120,000 gallons a day, or 85 gallons a minute, will be required in the summer. However, the potential capacity of the wells should be somewhat greater than 85 gallons a minute to allow for decline in yield. The author, who was assigned to this work by the United States Geological Survey, arrived in Oklahoma City April 21, 1931, and spent one week in field work in the area. After a conference with Dr. C.N. Gould, State Geologist of Oklahoma, it was decided that the possible sources of ground water to be investigated were the 'Red Beds' underlying the whole area, the Tertiary sands capping the hills north of the North Canadian River, and the river alluvium in the North Canadian River Valley. The area in which field work was done is shown on Plate 1 and includes approximately 105 square miles, lying chiefly north and west of El Reno, the county seat of Canadian County. (available as photostat copy only)

MicroEcos: Micro-Scale Explorations of Large-Scale Late Pleistocene Ecosystems

NASA Astrophysics Data System (ADS)

Gellis, B. S.

2017-12-01

Pollen data can inform the reconstruction of early-floral environments by providing data for artistic representations of what early-terrestrial ecosystems looked like, and how existing terrestrial landscapes have evolved. For example, what did the Bighorn Basin look like when large ice sheets covered modern Canada, the Yellowstone Plateau had an ice cap, and the Bighorn Mountains were mantled with alpine glaciers? MicroEcos is an immersive, multimedia project that aims to strengthen human-nature connections through the understanding and appreciation of biological ecosystems. Collected pollen data elucidates flora that are visible in the fossil record - associated with the Late-Pleistocene - and have been illustrated and described in botanical literature. It aims to make scientific data accessible and interesting to all audiences through a series of interactive-digital sculptures, large-scale photography and field-based videography. While this project is driven by scientific data, it is rooted in deeply artistic and outreach-based practices, which include broad artistic practices, e.g.: digital design, illustration, photography, video and sound design. Using 3D modeling and printing technology MicroEcos centers around a series of 3D-printed models of the Last Canyon rock shelter on the Wyoming and Montana border, Little Windy Hill pond site in Wyoming's Medicine Bow National Forest, and Natural Trap Cave site in Wyoming's Big Horn Basin. These digital, interactive-3D sculpture provide audiences with glimpses of three-dimensional Late-Pleistocene environments, and helps create dialogue of how grass, sagebrush, and spruce based ecosystems form. To help audiences better contextualize how MicroEcos bridges notions of time, space, and place, modern photography and videography of the Last Canyon, Little Windy Hill and Natural Trap Cave sites surround these 3D-digital reconstructions.

The Formation and Erosion History of Mt. Sharp

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Dapremont, Angela M.

2014-01-01

The Curiosity rover is exploring 155 km diameter Gale crater and Mt. Sharp, Gale's 5 km high central mound (Fig. 1). This study addresses the formation and erosion history of Mt. Sharp. Gale lies on the topographic dichotomy between the southern highlands and the northern plains - a drop of over 2 km [1,2]. Altitude differences between the north and south rim reflect this regional slope, as do altitude differences between the deep annulus north of Mt. Sharp and the southern crater floor. Orbiter and rover images demonstrate that most exposed areas on Mt. Sharp consist of thin, sub-parallel units interpreted as sedimentary layers [3]. Gale is typical of the 50 large martian craters that have been totally or partially filled with such layers [4,5]. In many craters these sediments have been deeply eroded. Central Peak and Peak Ring: The highest point on Mt. Sharp, near the crater's center, is interpreted as a central peak [6]. The peak has a massive lower portion and a thin, smooth capping deposit (Fig. 2). Gale's size is transitional between martian craters with single central peaks and craters with peak rings approximately half the crater's diameter [2,6]. The boundaries of Mt. Sharp, as well as an arc of hills to the southeast of the mountain, closely match a circle approximately 80 km in diameter (Fig. 3). This morphology suggests that the Gale impact may have formed both a central peak and a partial peak ring, which is covered by the sediments of Mt. Sharp in the north and possibly exposed in the arc of eroded hills in the southeast quadrant (Figs. 3,4).

Hypersomnia

MedlinePlus

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77 FR 50095 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-20

... Combine Hills I LLC, Avenal Park LLC, Sand Drag LLC, Sun City Project LLC, Eurus Combine Hills II LLC... Power Partners, LLC, Crescent Ridge LLC, Eurus Combine Hills I LLC, Avenal Park LLC, Sand Drag LLC, Sun..., Eurus Combine Hills I LLC, Avenal Park LLC, Sand Drag LLC, Sun City Project LLC, Eurus Combine Hills II...

Hume, Mill, Hill, and the Sui Generis Epidemiologic Approach to Causal Inference

PubMed Central

Morabia, Alfredo

2013-01-01

The epidemiologic approach to causal inference (i.e., Hill's viewpoints) consists of evaluating potential causes from the following 2, noncumulative angles: 1) established results from comparative, observational, or experimental epidemiologic studies; and 2) reviews of nonepidemiologic evidence. It does not involve statements of statistical significance. The philosophical roots of Hill's viewpoints are unknown. Superficially, they seem to descend from the ideas of Hume and Mill. Hill's viewpoints, however, use a different kind of evidence and have different purposes than do Hume's rules or Mill's system of logic. In a nutshell, Hume ignores comparative evidence central to Hill's viewpoints. Mill's logic disqualifies as invalid nonexperimental evidence, which forms the bulk of epidemiologic findings reviewed from Hill's viewpoints. The approaches by Hume and Mill cannot corroborate successful implementations of Hill's viewpoints. Besides Hume and Mill, the epidemiologic literature is clueless about a plausible, pre-1965 philosophical origin of Hill's viewpoints. Thus, Hill's viewpoints may be philosophically novel, sui generis, still waiting to be validated and justified. PMID:24071010

Hume, Mill, Hill, and the sui generis epidemiologic approach to causal inference.

PubMed

Morabia, Alfredo

2013-11-15

The epidemiologic approach to causal inference (i.e., Hill's viewpoints) consists of evaluating potential causes from the following 2, noncumulative angles: 1) established results from comparative, observational, or experimental epidemiologic studies; and 2) reviews of nonepidemiologic evidence. It does not involve statements of statistical significance. The philosophical roots of Hill's viewpoints are unknown. Superficially, they seem to descend from the ideas of Hume and Mill. Hill's viewpoints, however, use a different kind of evidence and have different purposes than do Hume's rules or Mill's system of logic. In a nutshell, Hume ignores comparative evidence central to Hill's viewpoints. Mill's logic disqualifies as invalid nonexperimental evidence, which forms the bulk of epidemiologic findings reviewed from Hill's viewpoints. The approaches by Hume and Mill cannot corroborate successful implementations of Hill's viewpoints. Besides Hume and Mill, the epidemiologic literature is clueless about a plausible, pre-1965 philosophical origin of Hill's viewpoints. Thus, Hill's viewpoints may be philosophically novel, sui generis, still waiting to be validated and justified.

An examination of Mars' north seasonal polar cap using MGS: Composition and infrared radiation balance

NASA Astrophysics Data System (ADS)

Hansen, Gary B.

2013-08-01

A detailed analysis of data from one revolution of the Mars Global Surveyor (MGS) is presented. Approximately 80% of this revolution observes the mid-winter northern seasonal polar cap, which covers the surface to <60°N, and which is predominantly within polar night. The surface composition and temperature are determined through analysis of 6-50 μm infrared spectra from the Thermal Emission Spectrometer (TES). The infrared radiative balance, which is the entire heat balance in the polar night except for small subsurface and atmospheric advection terms, is calculated for the surface and atmospheric column. The primary constituent, CO2 ice, also dominates the infrared spectral properties by variations in its grain size and by admixtures of dust and water ice, which cause large variations in the 20-50 μm emissivity. This is modified by incomplete areal coverage, and clouds or hazes. This quantitative analysis reveals CO2 grain radii ranging from ˜100 μm in isolated areas, to 1-5 mm in more widespread regions. The water ice content varies from none to about one part per thousand by mass, with a clear increase towards the periphery of the polar cap. The dust content is typically a few parts per thousand by mass, but is as much as an order of magnitude less abundant in "cold spot" regions, where the low emissivity of pure CO2 ice is revealed. This is the first quantitative analysis of thermal spectra of the seasonal polar cap and the first to estimate water ice content. Our models show that the cold spots represent cleaner, dust-free ice rather than finer grained ice than the background. Our guess is that the dust in cold spots is hidden in the center of the CO2 frost particles rather than not present. The fringes of the cap have more dust and water ice, and become patchy, with warmer water snow filling the gaps on the night side, and warmer bare soil on the day side. A low optical depth (<1 in the visible) water ice atmospheric haze is apparent on the night side, and appears with smaller optical depth on the day side. The infrared radiative balance at the surface is typically 20-25 W m-2 in the central polar cap, with ˜25% dips in the regions of dust-free CO2. The atmospheric radiative terms are typically 1-3 W m-2.

Weather Movie, Mars South Polar Region, March-April 2009 Close-up View

NASA Image and Video Library

2009-04-16

This image shows the southern high-latitudes region of Mars from March 19 through April 14, 2009, a period when regional dust storms occurred along the retreating edge of carbon-dioxide frost in the seasonal south polar cap. Compared with a full-hemisphere view (see PIA11987), this view shows more details of where the dust clouds formed and how they moved around the planet. The movie combines hundreds of images from the Mars Color Imager (MARCI) camera on NASA's Mars Reconnaissance Orbiter. In viewing the movie, it helps to understand some of the artifacts produced by the nature of MARCI images when seen in animation. MARCI acquires images in swaths from pole-to-pole during the dayside portion of each orbit. The camera can cover the entire planet in just over 12 orbits, and takes about 1 day to accumulate this coverage. The indiviual swaths are assembled into a mosaic, and that mosaic is shown here wrapped onto a sphere. The blurry portions of the mosaic, seen to be "pinwheeling" around the planet in the movie, are the portions of adjacent images viewing obliquely through the hazy atmosphsere. Portions with sharper-looking details are the central part of an image, viewing more directly downward through less atmosphere than the obliquely viewed portions. MARCI has a 180-degree field of view, and Mars fills about 78 percent of that field of view when the camera is pointed down at the planet. However, the Mars Reconnaissance Orbiter often is pointed to one side or the other off its orbital track in order to acquire targeted observations by the higher-resolution imaging systems on the spacecraft. When such rolls exceed about 20 degrees, gaps occur in the mosaic of MARCI swaths. Also, dark gaps appear when data are missing, either because of irrecoverable data drops, or because not all the data have yet been transmitted from the spacecraft. It isn't easy to see the actual dust motion in the atmosphere in these images, owing to the apparent motion of these artifacts. However, by concentrating on specific surface features (craters, prominent ice deposits, etc.) and looking for the brownish clouds of dust, it is possible to see where the storms start and how they move around the planet. In additon to tracking the storms, it is also interesting to watch how the seasonal cap shrinks from the beginning to the end of the animation. This shrinkage results from subliming of the carbon-dioxide frost from the surface as the frost absorbs southern hemisphere mid-spring sunlight. The temperature contrast between the warm sunlit ground just north of the cap's edge and the cold carbon-dioxide frost generates strong winds, enhanced by the excess carbon dioxide subliming off the cap. These winds create the conditions that lead to the dust storms. http://photojournal.jpl.nasa.gov/catalog/PIA11988

Distribution and Variability of Satellite-Derived Signals of Isolated Convection Initiation Events Over Central Eastern China

NASA Astrophysics Data System (ADS)

Huang, Yipeng; Meng, Zhiyong; Li, Jing; Li, Wanbiao; Bai, Lanqiang; Zhang, Murong; Wang, Xi

2017-11-01

This study combined measurements from the Chinese operational geostationary satellite Fengyun-2E (FY-2E) and ground-based weather radars to conduct a statistical survey of isolated convection initiation (CI) over central eastern China (CEC). The convective environment in CEC is modulated by the complex topography and monsoon climate. From May to August 2010, a total of 1,630 isolated CI signals were derived from FY-2E using a semiautomated method. The formation of these satellite-derived CI signals peaks in the early afternoon and occurs with high frequency in areas with remarkable terrain inhomogeneity (e.g., mountain, water, and mountain-water areas). The high signal frequency areas shift from northwest CEC (dry, high altitude) in early summer to southeast CEC (humid, low altitude) in midsummer along with an increasing monthly mean frequency. The satellite-derived CI signals tend to have longer lead times (the time difference between satellite-derived signal formation and radar-based CI) in the late morning and afternoon than in the early morning and night. During the early morning and night, the distinction between cloud top signatures and background terrestrial radiation becomes less apparent, resulting in delayed identification of the signals and thus short and even negative lead times. A decline in the lead time is observed from May to August, likely due to the increasing cloud growth rate and warm-rain processes. Results show increasing lead times with increasing landscape elevation, likely due to more warm-rain processes over the coastal sea and plain, along with a decreasing cloud growth rate from hill and mountain to the plateau.

Sensor data fusion for textured reconstruction and virtual representation of alpine scenes

NASA Astrophysics Data System (ADS)

Häufel, Gisela; Bulatov, Dimitri; Solbrig, Peter

2017-10-01

The concept of remote sensing is to provide information about a wide-range area without making physical contact with this area. If, additionally to satellite imagery, images and videos taken by drones provide a more up-to-date data at a higher resolution, or accurate vector data is downloadable from the Internet, one speaks of sensor data fusion. The concept of sensor data fusion is relevant for many applications, such as virtual tourism, automatic navigation, hazard assessment, etc. In this work, we describe sensor data fusion aiming to create a semantic 3D model of an extremely interesting yet challenging dataset: An alpine region in Southern Germany. A particular challenge of this work is that rock faces including overhangs are present in the input airborne laser point cloud. The proposed procedure for identification and reconstruction of overhangs from point clouds comprises four steps: Point cloud preparation, filtering out vegetation, mesh generation and texturing. Further object types are extracted in several interesting subsections of the dataset: Building models with textures from UAV (Unmanned Aerial Vehicle) videos, hills reconstructed as generic surfaces and textured by the orthophoto, individual trees detected by the watershed algorithm, as well as the vector data for roads retrieved from openly available shapefiles and GPS-device tracks. We pursue geo-specific reconstruction by assigning texture and width to roads of several pre-determined types and modeling isolated trees and rocks using commercial software. For visualization and simulation of the area, we have chosen the simulation system Virtual Battlespace 3 (VBS3). It becomes clear that the proposed concept of sensor data fusion allows a coarse reconstruction of a large scene and, at the same time, an accurate and up-to-date representation of its relevant subsections, in which simulation can take place.

Mars Global Surveyor: 7 Years in Orbit!

NASA Technical Reports Server (NTRS)

2004-01-01

12 September 2004 Today, 12 September 2004, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) team celebrates 7 Earth years orbiting Mars. MGS first reached the red planet and performed its critical orbit insertion burn on 12 September 1997. Over the past 7 years, MOC has returned over 170,000 images; its narrow angle camera has covered about 4.5% of the surface, and its wide angle cameras have viewed 100% of the planet nearly everyday.

At this time, MOC is not acquiring data because Mars is on the other side of the Sun relative to Earth. This period, known as Solar Conjunction, occurs about once every 26 months. During Solar Conjunction, no radio communications from spacecraft that are orbiting or have landed on Mars can be received. MOC was turned off on 7 September and is expected to resume operations on 25 September 2004, when Mars re-emerges from behind the Sun.

The rotating color image of Mars shown here was compiled from MOC red and blue wide angle daily global images acquired exactly 1 Mars year ago on 26 October 2002 (Ls 86.4o). In other words, Mars today (12 September 2004) should look about the same as the view provided here. Presently, Mars is in very late northern spring, and the north polar cap has retreated almost to its summer configuration. Water ice clouds form each afternoon at this time of year over the large volcanoes in the Tharsis and Elysium regions. A discontinuous belt of clouds forms over the martian equator; it is most prominent north of the Valles Marineris trough system. In the southern hemisphere, it is late autumn and the giant Hellas Basin floor is nearly white with seasonal frost cover. The south polar cap is not visible, it is enveloped in seasonal darkness. The northern summer and southern winter seasons will begin on 20 September 2004.

Recent Upgrades to the NASA Ames Mars General Circulation Model: Applications to Mars' Water Cycle

NASA Astrophysics Data System (ADS)

Hollingsworth, Jeffery L.; Kahre, M. A.; Haberle, R. M.; Montmessin, F.; Wilson, R. J.; Schaeffer, J.

2008-09-01

We report on recent improvements to the NASA Ames Mars general circulation model (GCM), a robust 3D climate-modeling tool that is state-of-the-art in terms of its physics parameterizations and subgrid-scale processes, and which can be applied to investigate physical and dynamical processes of the present (and past) Mars climate system. The most recent version (gcm2.1, v.24) of the Ames Mars GCM utilizes a more generalized radiation code (based on a two-stream approximation with correlated k's); an updated transport scheme (van Leer formulation); a cloud microphysics scheme that assumes a log-normal particle size distribution whose first two moments are treated as atmospheric tracers, and which includes the nucleation, growth and sedimentation of ice crystals. Atmospheric aerosols (e.g., dust and water-ice) can either be radiatively active or inactive. We apply this version of the Ames GCM to investigate key aspects of the present water cycle on Mars. Atmospheric dust is partially interactive in our simulations; namely, the radiation code "sees" a prescribed distribution that follows the MGS thermal emission spectrometer (TES) year-one measurements with a self-consistent vertical depth scale that varies with season. The cloud microphysics code interacts with a transported dust tracer column whose surface source is adjusted to maintain the TES distribution. The model is run from an initially dry state with a better representation of the north residual cap (NRC) which accounts for both surface-ice and bare-soil components. A seasonally repeatable water cycle is obtained within five Mars years. Our sub-grid scale representation of the NRC provides for a more realistic flux of moisture to the atmosphere and a much drier water cycle consistent with recent spacecraft observations (e.g., Mars Express PFS, corrected MGS/TES) compared to models that assume a spatially uniform and homogeneous north residual polar cap.

Regional scale climatic trends derived from Younger Dryas glaciers in Britain.

NASA Astrophysics Data System (ADS)

Pearce, Danni; Pellitero, Ramon; Rea, Brice R.; Barr, Iestyn; Small, David; McDougall, Des

2016-04-01

In Britain, the glacial geomorphological record has been utilised to infer palaeo-glacier geometries and ice dynamics, with much of this work focussing on the Younger Dryas (YD; c. 12.9 - 11.7 ka BP). During the YD the West Highlands ice-cap covered the majority of the Scottish Highlands, which is thought to have affected accumulation rates beyond the ice-cap margins, resulting in a steep (c. 80%) easterly decline in precipitation and smaller ice-masses. We present multi-proxy data investigating YD glaciation in the Tweedsmuir Hills, Southern Uplands, Scotland (55°46' N, 03°34' W). The area forms the most easterly upland region in the Southern Uplands and south of the West Highlands ice-cap, reaching an altitude of 840 m and covering c. 300 km2. Results of air-photo interpretation and field mapping, which utilised a morphostratigraphic approach, have demonstrated a more extensive glaciation than previously mapped, suggesting conditions were less arid than previously thought. The reconstruction consists of two separate icefields covering an area c. 60 km2 and new 14C dates of basal contact organics place the ice-mass within the context of the YD but new Cosmogenic Nuclide Analysis (CNA) of bedrock and in situ boulders, imply limited erosion and resetting occurred during the YD. Equilibrium Line Altitudes are calculated to have ranged from c. 419 - 634 m. Palaeo-precipitation values were derived using two precipitation-temperature relationships and suggest slightly lower totals than YD ice-masses located on the west coast of Britain but do not support a significant easterly reduction in precipitation. Analysis of present-day (c. 30 year) meteorological data across Britain demonstrates a pronounced reduction in precipitation of c. 50% on the east coast. This disparity between present-day and glacier-based YD precipitation patterns is partly attributable to the methodology employed in glacier reconstruction and questions the steep precipitation gradients thought to have been present. This data is placed within a Europe-wide context to elucidate glacier-climate patterns during the YD.

Birds of a high-altitude cloud forest in Alta Verapaz, Guatemala.

PubMed

Eisermann, Knut; Schulz, Ulrich

2005-01-01

The Northern Central American Highlands have been recognized as endemic bird area, but little is known about bird communities in Guatemalan cloud forests. From 1997 to 2001 a total of 142 bird species were recorded between 2000 and 2400 masl in cloud forest and agricultural clearings on Montaña Caquipec (Alta Verapaz, Guatemala). The bird community is described based on line transect counts within the forest. Pooling census data from undisturbed and disturbed forest, the Gray-breasted Wood-Wren (Henicorhina leucophrys) was found to be the most abundant species, followed in descending order by the Common Bush-Tanager (Chlorospingus ophthalmicus), the Paltry Tyrannulet (Zimmerius vilissimus), the Yellowish Flycatcher (Empidonax flavescens), the Ruddy-capped Nightingale-Thrush (Catharus frantzi), and the Amethyst-throated Hummingbird (Lampornis amethystinus). Bird communities in undisturbed and disturbed forest were found to be similar (Serensen similarity index 0.85), indicating low human impact. Of all recorded species, approximately 27% were Nearctic-Neotropical migratory birds. The most abundant one was the Wilson's Warbler (Wilsonia pusilla). The Montaña Caquipec is an important area for bird conservation, which is indicated by the presence of four species listed in the IUCN Red List (Highland Guan Penelopina nigra, Resplendent Quetzal Pharomachrus mocinno, Pink-headed Warbler Ergaticus versicolor, Golden-cheeked Warbler Dendroica chrysoparia), and 42 Mesoamerican endemics, of which 14 species are endemic to the Central American Highlands. The results presented here will be useful as baseline data for a long-term monitoring.

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

NASA Astrophysics Data System (ADS)

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Collins, Douglas B.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-07-01

The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer. In contrast, jet drops formed from the base of bursting bubbles are postulated to mainly produce larger supermicrometer particles from bulk seawater, which comprises largely salts and water-soluble organic species. However, here we demonstrate that jet drops produce up to 43% of total submicrometer SSA number concentrations, and that the fraction of SSA produced by jet drops can be modulated by marine biological activity. We show that the chemical composition, organic volume fraction, and ice nucleating ability of submicrometer particles from jet drops differ from those formed from film drops. Thus, the chemical composition of a substantial fraction of submicrometer particles will not be controlled by the composition of the sea surface microlayer, a major assumption in previous studies. This finding has significant ramifications for understanding the factors controlling the mixing state of submicrometer SSA particles and must be taken into consideration when predicting SSA impacts on clouds and climate.

Macroscopic Relationships among Latent Heating, Precipitation, Organized Convection and the Environment

NASA Technical Reports Server (NTRS)

Moncrieff, Mitchell W.; Liu, Changhai

2002-01-01

Three-dimensional Cloud Resolving Model (CRM) simulations were conducted to examine the squall line observed on 26 January, 1999 from the Tropical Rainfall Measuring Mission Large Scale Biosphere Atmosphere Experiment in Amazonia (TRMM-LBA) field campaign. The computational domain was 600 kilometers x 180 kilometers x 20 kilometers with a horizontal resolution of 1 kilometer and a vertical resolution of 200 meters. The CRM was initialized from the Abracos Hill and Rebio soundings. Convection was initiated by a surface-based and NW-SE oriented cold pool over a region 60 kilometers in the y-direction and 30 kilometers wide in the x-direction. The cold pool temperature perturbation is a maximum of -6K at the surface, decreasing linearly to zero at 3 kilometers. The simulated convection is in the form of a NW-SE band that moves toward the southwest at a speed of 8 meters per second, and is generally comparable to radar observations.

Imaging open-path Fourier transform infrared spectrometer for 3D cloud profiling

NASA Astrophysics Data System (ADS)

Rentz Dupuis, Julia; Mansur, David J.; Vaillancourt, Robert; Carlson, David; Evans, Thomas; Schundler, Elizabeth; Todd, Lori; Mottus, Kathleen

2010-04-01

OPTRA has developed an imaging open-path Fourier transform infrared (I-OP-FTIR) spectrometer for 3D profiling of chemical and biological agent simulant plumes released into test ranges and chambers. An array of I-OP-FTIR instruments positioned around the perimeter of the test site, in concert with advanced spectroscopic algorithms, enables real time tomographic reconstruction of the plume. The approach is intended as a referee measurement for test ranges and chambers. This Small Business Technology Transfer (STTR) effort combines the instrumentation and spectroscopic capabilities of OPTRA, Inc. with the computed tomographic expertise of the University of North Carolina, Chapel Hill. In this paper, we summarize the design and build and detail system characterization and test of a prototype I-OP-FTIR instrument. System characterization includes radiometric performance and spectral resolution. Results from a series of tomographic reconstructions of sulfur hexafluoride plumes in a laboratory setting are also presented.

Imaging open-path Fourier transform infrared spectrometer for 3D cloud profiling

NASA Astrophysics Data System (ADS)

Rentz Dupuis, Julia; Mansur, David J.; Engel, James R.; Vaillancourt, Robert; Todd, Lori; Mottus, Kathleen

2008-04-01

OPTRA and University of North Carolina are developing an imaging open-path Fourier transform infrared (I-OP-FTIR) spectrometer for 3D profiling of chemical and biological agent simulant plumes released into test ranges and chambers. An array of I-OP-FTIR instruments positioned around the perimeter of the test site, in concert with advanced spectroscopic algorithms, enables real time tomographic reconstruction of the plume. The approach will be considered as a candidate referee measurement for test ranges and chambers. This Small Business Technology Transfer (STTR) effort combines the instrumentation and spectroscopic capabilities of OPTRA, Inc. with the computed tomographic expertise of the University of North Carolina, Chapel Hill. In this paper, we summarize progress to date and overall system performance projections based on the instrument, spectroscopy, and tomographic reconstruction accuracy. We then present a preliminary optical design of the I-OP-FTIR.

Audio-magnetotelluric (AMT) study to investigate the genesis of Mujil hill

NASA Astrophysics Data System (ADS)

Rahmania, Suryanto, Wiwit

2017-07-01

Gunung Mujil is an isolated hill located near Pondoworejo village, Kalibawang sub-district, Kulon Progo district, and Special Province of Yogyakarta. The hill is part of the eastern Kulon Progo mountain range extended relatively in the North-South direction. The lithology of the hill consists of andesite breccia and it's similar with the Old Andesite Formation that built the Kulon Progo Mountains. There are at least two hypothesis about the genesis and the formation mechanism of this hill, (1) it was formed by debris mass from Kulon Progo Mountains, and (2) ) it was formed by an intrusion. Our study intended to determine the subsurface resistivity below the hill and to relating those results to with the scenario of the genesis of the Mujil hill. We conducted Audio-magnetotellurics (AMT) measurements along two lines survey crossing the Mujil hill consisting of 20 measurements. Since the measurements are located near the villages, most of the data has a fair to bad quality and only one station yielded an excellent data. A 1D Forward modeling was then applied to find best-fit model of the AMT data. The results shows that the Mujil hill was built by debris mass of the Old Andesite Formation from Kulon Progo mountain which is represented by a lower resistivity value under the Mujil hill.

Tectonic Implications of Changes in the Paleogene Paleodrainage Network in the West-Central Part of the San Luis Basin, Northern Rio Grande Rift, New Mexico and Colorado, USA

NASA Astrophysics Data System (ADS)

Thompson, R. A.; Turner, K. J.; Cosca, M. A.; Drenth, B.

2016-12-01

The San Luis Basin is the largest of extensional basins in the northern Rio Grande rift (>11,400 km2). The modern basin configuration is the result of Neogene deformation that has been the focus of numerous studies. In contrast, Paleogene extensional deformation is relatively little studied owing to a fragmentary or poorly exposed stratigraphic record in most areas. However, volcanic and volcaniclastic deposits exposed along the western margin of the basin provide the spatial and temporal framework for interpretation of paleodrainage patterns that changed in direct response to Oligocene basin subsidence and the migration of centers of Tertiary volcanism. The early Oligocene (34 to 30 Ma) drainage pattern that originated in the volcanic highlands of the San Juan Mountains flowed south into the northern Tusas Mountains. A structural and topographic high composed of Proterozoic rocks in the Tusas Mountains directed flow to the southeast at least as late as 29 Ma, as ash-flow tuffs sourced in the southeast San Juan Mountains are restricted to the north side of the paleohigh. Construction of volcanic highlands in the San Luis Hills between 30 and 28.5 Ma provided an abundant source of volcanic debris that combined with volcanic detritus sourced in the southeast San Juan Mountains and was deposited (Los Pinos Formation) throughout the northern Tusas Mountains progressively onlapping the paleotopographic high. By 29 Ma, subsidence of the Las Mesitas graben, a structural sub-basin, between the San Luis Hills and the southeast San Juan and northern Tusas Mountains is reflected by thick deposits of Los Pinos Formation beneath 26.5 Ma basalts. Regional tectonism responsible for the formation of the graben may have also lowered the topographic and structural high in the Tusas Mountains, which allowed development of a southwest-flowing paleodrainage that likely flowed onto the Colorado Plateau. Tholeiitic basalt flows erupted in the San Luis Hills at 25.8 Ma, that presently cap dip-slope surfaces 600 m above the basin floor, flowed southwest at least 50 km utilizing the paleodrainage. After emplacement of 20.5 Ma basalts along the margin of the southeast San Juan Mountains, uplift along the western margin of the basin reversed paleodrainage directions eastward into the incipient San Luis Basin.

Water Ice Clouds over the Northern Plains

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 14 May 2002) The Science This image, centered near 48.5 N and 240.5 W, displays splotchy water ice clouds that obscure the northern lowland plains in the region where the Viking 2 spacecraft landed. This image is far enough north to catch the edge of the north polar hood that develops during the northern winter. This is a cap of water and carbon dioxide ice clouds that form over the Martian north pole. As Mars progresses into northern spring, the persistent north polar hood ice clouds will dissipate and the surface viewing conditions will improve greatly. As the season develops, an equatorial belt of water ice clouds will form. This belt of water ice clouds is as characteristic of the Martian climate as the southern hemisphere summer dust storm season. Seasons on Mars have a dramatic effect on the state of the dynamic Martian atmosphere. The Story Muted in an almost air-brushed manner, this image doesn't have the crispness that most THEMIS images have. That's because clouds were rising over the surface of the red planet on the day this picture was taken. Finding clouds on Mars might remind us of conditions here on Earth, but these Martian clouds are made of frozen water and frozen carbon dioxide -- in other words, clouds of ice and 'dry ice.' Strange as that may sound, the clouds seen here form on a pretty regular basis at the north Martian pole during its winter season. As springtime comes to the northern hemisphere of Mars (and fall comes to the southern), these clouds will slowly disappear, and a nice belt of water ice clouds will form around the equator. So, if you were a THEMIS camera aimer, that might tell you when your best viewing conditions for different areas on Mars would be. As interesting as clear pictures of Martian landforms are, however, you wouldn't want to bypass the weather altogether. Pictures showing seasonal shifts are great for scientists to study, because they reveal a lot about the patterns of the Martian climate and the circulation of the atmosphere. There are a lot of interesting global climate relationships to study. For example, when it's winter in the north of Mars and clouds like the ones in this image form, dust storms rage in the south of Mars, where it's summer. So why does Mars have these wild seasons? Like the Earth, Mars is tilted on its axis. As it travels in its orbit around the sun, the angle between the Earth's axis and the Earth-Sun line changes. That's true for Mars as well. As each point on Mars spins on the rotating red planet each day, the part of the cycle spent in sunlight (day) and shadow (night) just aren't equal because of these angles. When day is longer than night (summer) in the north, night is longer than day (winter) in the south. Half a year later, when Mars has traveled in its orbit to the other side of the sun, the situation is exactly reversed. All this sounds familiar to Earthlings, but there's yet one more difference. Mars is farther away from the sun than the Earth. That means it takes longer for Mars to make a trip around the sun in its orbit than the Earth does -- about twice as long, in fact. That means that the seasons on Mars also last twice as long!

Marine boundary layer cloud regimes and POC formation in an LES coupled to a bulk aerosol scheme

NASA Astrophysics Data System (ADS)

Berner, A. H.; Bretherton, C. S.; Wood, R.; Muhlbauer, A.

2013-07-01

A large-eddy simulation (LES) coupled to a new bulk aerosol scheme is used to study long-lived regimes of aerosol-boundary layer cloud-precipitation interaction and the development of pockets of open cells (POCs) in subtropical stratocumulus cloud layers. The aerosol scheme prognoses mass and number concentration of a single log-normal accumulation mode with surface and entrainment sources, evolving subject to processing of activated aerosol and scavenging of dry aerosol by cloud and rain. The LES with the aerosol scheme is applied to a range of steadily-forced simulations idealized from a well-observed POC case. The long-term system evolution is explored with extended two-dimensional simulations of up to 20 days, mostly with diurnally-averaged insolation. One three-dimensional two-day simulation confirms the initial development of the corresponding two-dimensional case. With weak mean subsidence, an initially aerosol-rich mixed layer deepens, the capping stratocumulus cloud slowly thickens and increasingly depletes aerosol via precipitation accretion, then the boundary layer transitions within a few hours into an open-cell regime with scattered precipitating cumuli, in which entrainment is much weaker. The inversion slowly collapses for several days until the cumulus clouds are too shallow to efficiently precipitate. Inversion cloud then reforms and radiatively drives renewed entrainment, allowing the boundary layer to deepen and become more aerosol-rich, until the stratocumulus layer thickens enough to undergo another cycle of open-cell formation. If mean subsidence is stronger, the stratocumulus never thickens enough to initiate drizzle and settles into a steady state. With lower initial aerosol concentrations, this system quickly transitions into open cells, collapses, and redevelops into a different steady state with a shallow, optically thin cloud layer. In these steady states, interstitial scavenging by cloud droplets is the main sink of aerosol number. The system is described in a reduced two-dimensional phase plane with inversion height and boundary-layer average aerosol concentrations as the state variables. Simulations with a full diurnal cycle show similar evolutions, except that open-cell formation is phase-locked into the early morning hours. The same steadily-forced modeling framework is applied to the development and evolution of a POC and the surrounding overcast boundary layer. An initial aerosol perturbation applied to a portion of the model domain leads that portion to transition into open-cell convection, forming a POC. Reduced entrainment in the POC induces a negative feedback between areal fraction covered by the POC and boundary layer depth changes. This stabilizes the system by controlling liquid water path and precipitation sinks of aerosol number in the overcast region, while also preventing boundary-layer collapse within the POC, allowing the POC and overcast to coexist indefinitely in a quasi-steady equilibrium.

Comparison of Speed-Up Over Hills Derived from Wind-Tunnel Experiments, Wind-Loading Standards, and Numerical Modelling

NASA Astrophysics Data System (ADS)

Safaei Pirooz, Amir A.; Flay, Richard G. J.

2018-03-01

We evaluate the accuracy of the speed-up provided in several wind-loading standards by comparison with wind-tunnel measurements and numerical predictions, which are carried out at a nominal scale of 1:500 and full-scale, respectively. Airflow over two- and three-dimensional bell-shaped hills is numerically modelled using the Reynolds-averaged Navier-Stokes method with a pressure-driven atmospheric boundary layer and three different turbulence models. Investigated in detail are the effects of grid size on the speed-up and flow separation, as well as the resulting uncertainties in the numerical simulations. Good agreement is obtained between the numerical prediction of speed-up, as well as the wake region size and location, with that according to large-eddy simulations and the wind-tunnel results. The numerical results demonstrate the ability to predict the airflow over a hill with good accuracy with considerably less computational time than for large-eddy simulation. Numerical simulations for a three-dimensional hill show that the speed-up and the wake region decrease significantly when compared with the flow over two-dimensional hills due to the secondary flow around three-dimensional hills. Different hill slopes and shapes are simulated numerically to investigate the effect of hill profile on the speed-up. In comparison with more peaked hill crests, flat-topped hills have a lower speed-up at the crest up to heights of about half the hill height, for which none of the standards gives entirely satisfactory values of speed-up. Overall, the latest versions of the National Building Code of Canada and the Australian and New Zealand Standard give the best predictions of wind speed over isolated hills.

Uniform and Multi-Grid Modeling of Acoustic Wave Propagation With Cellular Automaton Techniques

DTIC Science & Technology

2013-03-01

39 Figure 26. CurrvedHillIndices fuction used to created a curved hill in the bottom...to safe passage of a submarine. Driving factors influencing SONAR improvements have alluded to the fact that primary naval missions have shifted from...CurvedHillIndices function after reaching line 12 42 Figure 26. CurrvedHillIndices fuction used to created a curved hill in the bottom of any 2D or

Climate change and apple farming in Indian Himalayas: a study of local perceptions and responses.

PubMed

Basannagari, Basavaraj; Kala, Chandra Prakash

2013-01-01

Apple farming is an important activity and profession of farmer communities in the Himalayan states of India. At present, the traditional apple farming is under stress due to changes in climate. The present study was undertaken in an Indian Himalayan state, Himachal Pradesh, with the major aim of studying perceptions of farmers on the effects of climate change on apple farming along the altitudinal gradient. Through questionnaire survey, the perceptions of farmers were recorded at low hills (<2500 m), mid-hills (2500-3000 m), and upper hills (>3000 m). At all elevation range the majority of farmers reported that there was increase in atmospheric temperature, and hence at low hills 72% farmers believed that this increase in temperature was responsible for decline in fruit size and so that the quality. Thirty five percent farmers at high hills and 30% at mid hills perceived frost as a major cause for damaging apple farming whereas at low hills 24% farmers perceived hailstorm as the major deterrent for apple farming. The majority of farmers, along the altitude (92% at high hills, 79% at mid hills and 83% at low hills), reported decrease in snowfall. The majority of farmers at low altitude and mid altitude reported decline in apple farming whereas 71% farmers at high hill areas refused decline in apple farming. About 73-83% farmers admitted delay in apple's harvesting period. At mid hills apple scab and at low hills pest attack on apple crops are considered as the indicators of climate change. The change in land use practices was attributed to climate change and in many areas the land under apple farming was replaced for production of coarse grains, seasonal vegetables and other horticulture species. Scientific investigation claiming changes in Indian Himalayan climate corroborates perceptions of farmers, as examined during the present study.

77 FR 75120 - Black Hills National Forest Advisory Board

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-19

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board will... copying. The public may inspect comments received at the Supervisor's Office, Black Hills National Forest...

78 FR 65962 - Black Hills National Forest Advisory Board

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-04

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of cancellation of meeting of the Black Hills National Forest Advisory Board. SUMMARY: The U. S. Department of Agriculture, Forest Service, Black Hills National Forest cancelled the...

Seismic evidence of Quaternary faulting in the Benton Hills area, southeast Missouri

USGS Publications Warehouse

Palmer, J.R.; Shoemaker, M.; Hoffman, D.; Anderson, N.L.; Vaughn, J.D.; Harrison, R.W.

1997-01-01

Two reflection seismic profiles at English Hill, across the southern edge of the Benton Hills escarpment, southeast Missouri, establish that geologic structures at English Hill are of tectonic origin. The lowland area to the south of the escarpment is relatively undisturbed. The geology at English Hill is structurally complex, and reflection seismic and geologic data indicate extensive and episodic faulting of Paleozoic, Cretaceous, Tertiary, and Quaternary strata. The individual faults have near-vertical fault surfaces with maximum vertical separations on the order of 15 m. They appear to be clustered in north-northeast trending zones that essentially parallel one of the dominant Benton Hills structural trends. These observations suggest that previously mapped Quaternary faults at English Hill are deep-seated and tectonic in origin. This paper documents recent faulting at English Hill and is the first time late Quaternary, surface-rupture faulting has been recognized in the middle Mississippi River Valley region outside of the New Madrid seismic zone. This has important implications for earthquake assessment in the midcontinent.

Variable Stars in Large Magellanic Cloud Globular Clusters. III. Reticulum

NASA Astrophysics Data System (ADS)

Kuehn, Charles A.; Dame, Kyra; Smith, Horace A.; Catelan, Márcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2013-06-01

This is the third in a series of papers studying the variable stars in old globular clusters in the Large Magellanic Cloud. The primary goal of this series is to look at how the characteristics and behavior of RR Lyrae stars in Oosterhoff-intermediate systems compare to those of their counterparts in Oosterhoff-I/II systems. In this paper we present the results of our new time-series BVI photometric study of the globular cluster Reticulum. We found a total of 32 variables stars (22 RRab, 4 RRc, and 6 RRd stars) in our field of view. We present photometric parameters and light curves for these stars. We also present physical properties, derived from Fourier analysis of light curves, for some of the RR Lyrae stars. We discuss the Oosterhoff classification of Reticulum and use our results to re-derive the distance modulus and age of the cluster. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

Developing Verification Systems for Building Information Models of Heritage Buildings with Heterogeneous Datasets

NASA Astrophysics Data System (ADS)

Chow, L.; Fai, S.

2017-08-01

The digitization and abstraction of existing buildings into building information models requires the translation of heterogeneous datasets that may include CAD, technical reports, historic texts, archival drawings, terrestrial laser scanning, and photogrammetry into model elements. In this paper, we discuss a project undertaken by the Carleton Immersive Media Studio (CIMS) that explored the synthesis of heterogeneous datasets for the development of a building information model (BIM) for one of Canada's most significant heritage assets - the Centre Block of the Parliament Hill National Historic Site. The scope of the project included the development of an as-found model of the century-old, six-story building in anticipation of specific model uses for an extensive rehabilitation program. The as-found Centre Block model was developed in Revit using primarily point cloud data from terrestrial laser scanning. The data was captured by CIMS in partnership with Heritage Conservation Services (HCS), Public Services and Procurement Canada (PSPC), using a Leica C10 and P40 (exterior and large interior spaces) and a Faro Focus (small to mid-sized interior spaces). Secondary sources such as archival drawings, photographs, and technical reports were referenced in cases where point cloud data was not available. As a result of working with heterogeneous data sets, a verification system was introduced in order to communicate to model users/viewers the source of information for each building element within the model.

Results of land cover change detection analysis in and around Cordillera Azul National Park, Peru

USGS Publications Warehouse

Sleeter, Benjamin M.; Halsing, David L.

2005-01-01

The first product of the Optimizing Design and Management of Protected Areas for Conservation Project is a land cover change detection analysis based on Landsat thematic mapper (TM) and enhanced thematic mapper plus (ETM+) imagery collected at intervals between 1989 and 2002. The goal of this analysis was to quantify and analyze patterns of forest clearing, land conversion, and other disturbances in and around the Cordillera Azul National Park in Peru. After removing clouds and cloud shadows from the imagery using a series of automatic and manual processes, a Tasseled Cap Transformation was used to detect pixels of high reflectance, which were classified as bare ground and areas of likely forest clearing. Results showed a slow but steady increase in cleared ground prior to 1999 and a rapid and increasing conversion rate after that time. The highest concentrations of clearings have spread upward from the western border of the study area on the Huallaga River. To date, most disturbances have taken place in the buffer zone around the park, not within it, but the data show dense clearings occurring closer to the park border each year.

78 FR 73187 - Black Hills National Forest Advisory Board

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-05

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Black Hills National Forest Advisory Board (Board... the Black Hills National Forest in South Dakota; and (4) update and report on Mountain Pine Beetle...

77 FR 8214 - Black Hills National Forest Advisory Board

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest Advisory Board AGENCY: USDA Forest Service. ACTION: Notice of intent to re-establish the Black Hills National Forest Advisory Board...-establish the Black Hills National Forest Advisory Board (Board). The purpose is to obtain advice and...

75 FR 65315 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-22

.... Applicants: Black Hills Power, Inc., Black Hills/Colorado Electric Utility Co, Black Hills Wyoming, LLC, Cheyenne Light, Fuel and Power Company. Description: Updated Market Power Analysis of the Black Hills... LLC submits tariff filing per 35.17(b): Amendment to Market-Based Rate Application Reflecting Change...

Genetic diversity and structure in hill rice (Oryza sativa L.) landraces from the North-Eastern Himalayas of India.

PubMed

Roy, Somnath; Marndi, B C; Mawkhlieng, B; Banerjee, A; Yadav, R M; Misra, A K; Bansal, K C

2016-07-13

Hill rices (Oryza sativa L.) are direct seeded rices grown on hill slopes of different gradients. These landraces have evolved under rainfed and harsh environmental conditions and may possess genes governing adaptation traits such as tolerance to cold and moisture stress. In this study, 64 hill rice landraces were collected from the state of Arunachal Pradesh of North-Eastern region of India, and assessed by agro-morphological variability and microsatellite markers polymorphism. Our aim was to use phenotypic and genetic diversity data to understand the basis of farmers' classification of hill rice landraces into two groups: umte and tening. Another goal was to understand the genetic differentiation of hill rices into Indica or japonica subspecies. According to farmers' classification, hill rices were categorized into two groups: umte (large-grained, late maturing) and tening (small-grained, early maturing). We did not find significant difference in days to 50 % flowering between the groups. Principal component analysis revealed that two groups can be distinguished on the basis of kernel length-to-width ration (KLW), kernel length (KL), grain length (GrL), grain length-to-width ration (GrLW) and plant height (Ht). Stepwise canonical discriminant analysis identified KL and Ht as the main discriminatory characters between the cultivar groups. Genetic diversity analysis with 35 SSR markers revealed considerable genetic diversity in the hill rice germplasm (gene diversity: 0.66; polymorphism information content: 0.62). Pair-wise allelic difference between umte and tening groups was not statistically significant. The model-based population structure analysis showed that the hill rices were clustered into two broad groups corresponding to Indica and Japonica. The geographic distribution and cultivars grouping of hill rices were not congruent in genetic clusters. Both distance- and model-based approaches indicated that the hill rices were predominantly japonica or admixture among the groups within the subspecies. These findings were further supported by combined analysis hill rices with 150 reference rice accessions representing major genetic groups of rice. This study collected a valuable set of hill rice germplasm for rice breeding and for evolutionary studies. It also generated a new set of information on genetic and phenotypic diversity of hill rice landraces in North-Eastern region of India. The collected hill rices were mostly japonica or admixture among the subpopulations of Indica or Japonica. The findings are useful for utilization and conservation of hill rice germplasm.

San Marco C-2 (San Marco-4) Post Launch Report No. 1

NASA Technical Reports Server (NTRS)

1974-01-01

The San Marco C-2 spacecraft, now designated San Marco-4, was successfully launched by a Scout vehicle from the San Marco Platform on 18 February 1974 at 6:05 a.m. EDT. The launch occurred 2 hours 50 minutes into the 3-hour window due co low cloud cover at the launch site. All spacecraft subsystems have been checked and are functioning normally. The protective caps for the two U.S. experiments were ejected and the Omegatron experiment activated on 19 February. The neutral mass spectrometer was activated as scheduled on 22 February after sufficient time to allow for spacecraft outgassing and to avoid the possibility of corona occurring. Both instruments are performing properly and worthwhile scientific data is being acquired.

Vortex rings from Sphagnum moss capsules

NASA Astrophysics Data System (ADS)

Whitaker, Dwight; Strassman, Sam; Cha, Jung; Chang, Emily; Guo, Xinyi; Edwards, Joan

2010-11-01

The capsules of Sphagnum moss use vortex rings to disperse spores to suitable habitats many kilometers away. Vortex rings are created by the sudden release of pressurized air when the capsule ruptures, and are an efficient way to carry the small spores with low terminal velocities to heights where they can be carried by turbulent wind currents. We will present our computational model of these explosions, which are carried out using a 2-D large eddy simulation (LES) on FLUENT. Our simulations can reproduce the observed motion of the spore clouds observed from moss capsules with high-speed videos, and we will discuss the roles of bursting pressure, cap mass, and capsule morphology on the formation and quality of vortex rings created by this plant.

Long-term changes in explosive and effusive behaviour at andesitic arc volcanoes: Chronostratigraphy of the Centre Hills Volcano, Montserrat

NASA Astrophysics Data System (ADS)

Coussens, Maya; Cassidy, Michael; Watt, Sebastian F. L.; Jutzeler, Martin; Talling, Peter J.; Barfod, Dan; Gernon, Thomas M.; Taylor, Rex; Hatter, Stuart J.; Palmer, Martin R.; Montserrat Volcano Observatory

2017-03-01

Volcanism on Montserrat (Lesser Antilles arc) has migrated southwards since the formation of the Silver Hills 2.5 Ma, and has formed three successively active volcanic centres. The Centre Hills volcano was the focus of volcanism from 1-0.4 Ma, before activity commenced at the currently active Soufrière Hills volcano. The history of activity at these two volcanoes provides an opportunity to investigate the pattern of volcano behaviour on an andesitic arc island over the lifetime of individual volcanoes. Here, we describe the pyroclastic stratigraphy of subaerial exposures around central Montserrat; identifying 11 thick (> 1 m) pumiceous units derived from sustained explosive eruptions of Centre Hills from 0.8-0.4 Ma. Over 10 other, less well- exposed pumiceous units have also been identified. The pumice-rich units are interbedded with andesite lava breccias derived from effusive, dome-forming eruptions of Centre Hills. The stratigraphy indicates that large (up to magnitude 5) explosive eruptions occurred throughout the history of Centre Hills, alongside effusive activity. This behaviour at Centre Hills contrasts with Soufrière Hills, where deposits from sustained explosive eruptions are much less common and restricted to early stages of activity at the volcano, from 175-130 ka. Subsequent eruptions at Soufriere Hills have been dominated by andesitic effusive eruptions. The bulk composition, petrography and mineral chemistry of volcanic rocks from Centre Hills and Soufrière Hills are similar throughout the history of both volcanoes, except for occasional, transient departures to different magma compositions, which mark shifts in vent location or dominant eruption style. For example, the final recorded eruption of Centre Hills, before the initiation of activity at Soufrière Hills, was more silicic than any other identified eruption on Montserrat; and the basaltic South Soufrière Hills episode marked the transition to the current stage of predominantly effusive Soufrière Hills activity. The compositional stability observed throughout the history of Centre Hills and Soufrière Hills suggests that a predominance towards effusive or explosive eruption styles is not driven by major compositional shifts of magma, but may reflect local changes in long-term magma storage conditions that characterise individual episodes (on 105 year timescales) of volcanism on Montserrat. Supplementary Table 2: Complete XRF analyses for all analysed samples Supplementary Table 3: Complete ICP-MS analyses for all analysed samples. Supplementary Table 4: Plagioclase composition and precision data from SEM analysis Supplementary Table 5: Clinopyroxene composition and precision data from SEM analysis Supplementary Table 6: Orthopyroxene composition and precision data from SEM analysis Supplementary Table 7: Amphibole composition and precision data from SEM analysis Supplementary Table 8: Glass compositions from EMP analysis Supplementary Table 9: Standard Deviation of glass compositions from EMP analysis. Supplementary Table 10: Isotopic composition of argon from plagioclase crystals from select units. Data obtained using an ARGUS V multi-collector mass spectrometer.

78 FR 48466 - Comcast Cable, West Division Customer Care, Morgan Hill, California; Notice of Negative...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-08

... Division Customer Care, Morgan Hill, California; Notice of Negative Determination on Reconsideration On... Reconsideration for the workers and former workers of Comcast Cable, West Division Customer Care, Morgan Hill... the petition for group eligibility of Comcast Cable, West Division Customer Care, Morgan Hill...

75 FR 28302 - American Food and Vending Spring Hill, TN; Notice of Negative Determination Regarding Application...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-20

... Spring Hill, TN; Notice of Negative Determination Regarding Application for Reconsideration By... negative determination applicable to workers and former workers at American Food and Vending, Spring Hill... eligible for TAA because they are service workers who provided services to General Motors, Spring Hill...

The Polar Regions and Martian Climate: Studies with a Global Climate Model

NASA Technical Reports Server (NTRS)

Wilson, R. J.; Richardson, M. I.; Smith, M. D.

2003-01-01

Much of the interest in the polar regions centers on the fact that they likely contain the best record of Martian climate change on time scales from years to eons. This expectation is based upon the observed occurrence of weathering product deposits and volatile reservoirs that are coupled to the climate. Interpretation and understanding of these records requires understanding of the mechanisms that involve the exchange of dust, water, and carbon dioxide between the surface and atmosphere, and the atmospheric redistribution of these species. We will summarize our use of the GFDL Mars general circulation model (MGCM), to exploration aspects of the interaction between the global climate and the polar regions. For example, our studies have shown that while the northern polar cap is the dominant seasonal source for water, it can act as a net annual source or sink for water, depending upon the cap temperatures and the bulk humidity of the atmosphere. This behavior regulates the annual and global average humidity of the atmosphere, as the cap acts as a sink if the atmosphere is too wet and a source if it is too dry. We will then focus our presentation on the ability of the MGCM to simulate the observed diurnal variations of surface temperature. We are particularly interested in assessing the influence of dust aerosol and water ice clouds on simulated surface temperature and the comparison with observations. Surface thermal inertia and albedo are critical boundary inputs for MGCM simulations. Thermal inertia is also of intrinsic interest as it may be related to properties of the surface such as particle size and surface character.

Springtime Dust Storm Swirls at Martian North Pole

NASA Technical Reports Server (NTRS)

1996-01-01

Two Hubble Space Telescope images of Mars, taken about a month apart on September 18 and October 15, 1996, reveal a state-sized dust storm churning near the edge of the Martian north polar cap. The polar storm is probably a consequence of large temperature differences between the polar ice and the dark regions to the south, which are heated by the springtime sun. The increased sunlight also causes the dry ice in the polar cap to sublime and shrink.

Mars is famous for large, planet-wide dust storms. Smaller storms resembling the one seen here were observed in other regions by Viking orbiters in the late 1970s. However, this is the first time that such an event has been caught near the receding north polar cap. The Hubble images provide valuable new insights into the behavior of localized dust storms on Mars, which are typically below the resolution of ground-based telescopes. This kind of advanced planetary 'weather report' will be invaluable for aiding preparation for the landing of NASA's Pathfinder spacecraft in July 1997 and the arrival of Mars Global Surveyor orbiter in September 1997.

Top (September 18, 1996) - The salmon colored notch in the white north polar cap is a 600-mile (1,000 kilometer) long storm -- nearly the width of Texas. The bright dust can also be seen over the dark surface surrounding the cap, where it is caught up in the Martian jet stream and blown easterly. The white clouds at lower latitudes are mostly associated with major Martian volcanos such as Olympus Mons. This image was taken when Mars was more than 186 million miles (300 million kilometers) from Earth, and the planet was smaller in angular size than Jupiter's Great Red Spot!

Bottom (October 15, 1996) - Though the storm has dissipated by October, a distinctive dust-colored comma-shaped feature can be seen curving across the ice cap. The shape is similar to cold fronts on Earth, which are associated with low pressure systems. Nothing quite like this feature has been seen previously either in ground-based or spacecraft observation. The snow line marking the edge of the cap receded northward by approximately 120 miles (200 kilometers), while the distance to the Red Planet narrowed to 170 million miles (275 million kilometers).

Technical notes: To help compare locations and sizes of features, map projections (right of each disk) are centered on the geographic north pole. Maps are oriented with 0 degrees longitude at the top and show meridians every 45 degrees of longitude (longitude increases clockwise); latitude circles are also shown for 40, 60, and 80 degrees north latitude. The color images were assembled from separate exposures taken with the Wide Field Planetary Camera 2.

This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http:// oposite.stsci.edu/pubinfo/

Observations of an aeolian landscape: From surface to orbit in Gale Crater

NASA Astrophysics Data System (ADS)

Day, Mackenzie; Kocurek, Gary

2016-12-01

Landscapes derived solely from aeolian processes are rare on Earth because of the dominance of subaqueous processes. In contrast, aeolian-derived landscapes should typify Mars because of the absence of liquid water, the long exposure times of surfaces, and the presence of wind as the default geomorphic agent. Using the full range of available orbital and Mars Science Laboratory rover Curiosity images, wind-formed features in Gale Crater were cataloged and analyzed in order to characterize the aeolian landscape and to derive the evolution of the crater wind regime over time. Inferred wind directions show a dominance of regional northerly winds over geologic time-scales, but a dominance of topography-driven katabatic winds in modern times. Landscapes in Gale Crater show a preponderance of aeolian features at all spatial scales. Interpreted processes forming these features include first-cycle aeolian abrasion of bedrock, pervasive deflation, organization of available sand into bedforms, abundant cratering, and gravity-driven wasting, all of which occur over a background of slow physical weathering. The observed landscapes are proposed to represent a spectrum of progressive surface denudation from fractured bedrock, to retreating bedrock-capped mesas, to remnant hills capped by bedrock rubble, to desert pavement plains. This model of landscape evolution provides the mechanism by which northerly winds acting over ∼3 Ga excavated tens of thousands of cubic kilometers of material from the once sediment-filled crater, thus carving the intra-crater moat and exhuming Mount Sharp (Aeolis Mons). The current crater surface is relatively sand-starved, indicating that potential sediment deflation from the crater is greater than sediment production, and that most exhumation of Mount Sharp occurred in the ancient geologic past.

KSC-99pp1440

NASA Image and Video Library

1999-12-17

A cloud-streaked sky provides backdrop for Space Shuttle Discovery as it waits for liftoff on mission STS-103 from Launch Pad 39B. The tower at its left is the Fixed Service Structure, topped by the 80-foot-tall fiberglass mast that helps provide protection from lightning strikes. Below it, extending outward, is the external tank gaseous oxygen vent arm system with the vent hood (commonly called the "beanie cap") poised above the external tank. The retractable arm and the beanie cap are designed to vent gaseous oxygen vapors away from the Space Shuttle. The arm truss section is 65 feet long and the diameter of the vent hood is 13 feet. Extending toward the cabin of the orbiter below is the orbiter access arm, with the environmental chamber (called the White Room) at the end. Through this chamber the crew enters the orbiter. The STS-103 mission, to service the Hubble Space Telescope, is scheduled for launch Dec. 17 at 8:47 p.m. EST. Mission objectives include replacing gyroscopes and an old computer, installing another solid state recorder, and replacing damaged insulation in the telescope. The mission is expected to last about 8 days and 21 hours. Discovery is expected to land at KSC Sunday, Dec. 26, at about 6:25 p.m. EST

Cassini observations of carbon-based anions in Titan's ionosphere

NASA Astrophysics Data System (ADS)

Desai, Ravindra; Lewis, Gethyn; Waite, J. Hunter; Kataria, Dhiren; Wellbrock, Anne; Jones, Geraint; Coates, Andrew

2016-07-01

Cassini observations of Titan's ionosphere revealed an atmosphere rich in positively and negatively charged ions and organic molecules. The detection of large quantities of negatively charged ions was particularly surprising and adds Titan to the growing list of locations where anion chemistry has been observed to play an important role. In this study we present updated analysis on these negatively charged ions through an enhanced understanding of the Cassini CAPS Electron Spectrometer (CAPS-ELS) instrument response. The ionisation of Titan's dominant atmospheric constituent, N2, by the HeII Solar line, results in an observable photoelectron population at 24.1eV which we use to correct for differential spacecraft charging. Correcting for further energy-angle signatures within this dataset, we use an updated fitting procedure to show how the ELS mass spectrum, previously grouped into broad mass ranges, can be resolved into specific peaks at multiples of carbon-based anion species up to over 100amu/q. These peaks are shown to be ubiquitous within Titan's upper atmosphere and reminiscent of carbon-based anions identified in dense molecular clouds beyond our Solar System. It is thus shown how the moon Titan in the Outer Solar System can be used as an analogue to study these even more remote and exotic astrophysical environments.

The Boeing Delta II rocket with Mars Polar Lander aboard lifts off at Pad 17B, CCAS

NASA Technical Reports Server (NTRS)

1999-01-01

Amid clouds of exhaust, a Boeing Delta II expendable launch vehicle with NASA's Mars Polar Lander clears Launch Complex 17B, Cape Canaveral Air Station, after launch at 3:21:10 p.m. EST. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

The Boeing Delta II rocket with Mars Polar Lander aboard lifts off at Pad 17B, CCAS

NASA Technical Reports Server (NTRS)

1999-01-01

A Boeing Delta II expendable launch vehicle lifts off with NASA's Mars Polar Lander into a cloud-covered sky at 3:21:10 p.m. EST from Launch Complex 17B, Cape Canaveral Air Station. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south polar cap, which consists of carbon dioxide ice. The lander will study the polar water cycle, frosts, water vapor, condensates and dust in the Martian atmosphere. It is equipped with a robotic arm to dig beneath the layered terrain at the polar cap. In addition, Deep Space 2 microprobes, developed by NASA's New Millennium Program, are installed on the lander's cruise stage. After crashing into the planet's surface, they will conduct two days of soil and water experiments up to 1 meter (3 feet) below the Martian surface, testing new technologies for future planetary descent probes. The lander is the second spacecraft to be launched in a pair of Mars Surveyor '98missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

Hill functions for stochastic gene regulatory networks from master equations with split nodes and time-scale separation

NASA Astrophysics Data System (ADS)

Lipan, Ovidiu; Ferwerda, Cameron

2018-02-01

The deterministic Hill function depends only on the average values of molecule numbers. To account for the fluctuations in the molecule numbers, the argument of the Hill function needs to contain the means, the standard deviations, and the correlations. Here we present a method that allows for stochastic Hill functions to be constructed from the dynamical evolution of stochastic biocircuits with specific topologies. These stochastic Hill functions are presented in a closed analytical form so that they can be easily incorporated in models for large genetic regulatory networks. Using a repressive biocircuit as an example, we show by Monte Carlo simulations that the traditional deterministic Hill function inaccurately predicts time of repression by an order of two magnitudes. However, the stochastic Hill function was able to capture the fluctuations and thus accurately predicted the time of repression.

Arcadia Planitia Hills

NASA Image and Video Library

2018-04-25

The rounded hills in this VIS image are located in Arcadia Planitia. Broad linear ridges and groups of hills in this region are part of Phlegra Dorsa (ridges) and Phlegra Montes (hills). Orbit Number: 71248 Latitude: 30.6712 Longitude: 171.018 Instrument: VIS Captured: 2018-01-05 17:05 https://photojournal.jpl.nasa.gov/catalog/PIA22377

75 FR 63465 - Hill-Lake Gas Storage, LLC; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-15

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-137-000] Hill-Lake Gas Storage, LLC; Notice of Filing October 7, 2010. Take notice that on September 30, 2010, Hill-Lake Gas Storage, LLC (Hill-Lake) filed a revised Statement of Operating Conditions (SOC) for its Storage Services...

75. Southeast elevation of Forest Hills station looking Northwest ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

75. Southeast elevation of Forest Hills station - looking Northwest from junction of Washington and Walk Hill Streets. At left is the beginning of Section F-7 the exposed steel portion of elevated structure leading to the Forest Hills storage yard (demolished in 1985). - Boston Elevated Railway, Elevated Mainline, Washington Street, Boston, Suffolk County, MA

Simulations of the September 1987 lower thermospheric tides with the National Center for Atmospheric Research thermosphere-ionosphere general circulation model

NASA Astrophysics Data System (ADS)

Fesen, C. G.; Roble, R. G.

1991-02-01

The NCAR thermosphere-ionosphere general circulation model (TIGCM) was used to simulate incoherent scatter radar observations of the lower thermosphere tides during the first Lower Thermosphere Coupling Study (LTCS) campaign, September 21-26, 1987. The TIGCM utilized time-varying histories of the model input fields obtained from the World Data Center for the LTCS period. The model inputs included solar flux, total hemispheric power, solar wind data from which the cross-polar-cap potential was derived, and geomagnetic Kp index. Calculations were made for the semidiurnal ion temperatures and horizontal neutral winds at locations representative of Arecibo, Millstone Hill, and Sondrestrom. Tidal inputs to the TIGCM lower boundary were obtained from the middle atmosphere model of Forbes and Vial (1989). The TIGCM tidal structures are in fair general agreement with the observations. The amplitudes tended to be better simulated than the phases, and the mid- and high-latitude locations are simulated better than the low-latitude thermosphere. The model simulations were used to investigate the daily variability of the tides due to the geomagnetic activity occurring during this period.

Shaded Relief of Rio Sao Francisco, Brazil

NASA Image and Video Library

2000-02-14

This topographic image acquired by SRTM shows an area south of the Sao Francisco River in Brazil. The scrub forest terrain shows relief of about 400 meters (1300 feet). Areas such as these are difficult to map by traditional methods because of frequent cloud cover and local inaccessibility. This region has little topographic relief, but even subtle changes in topography have far-reaching effects on regional ecosystems. The image covers an area of 57 km x 79 km and represents one quarter of the 225 km SRTM swath. Colors range from dark blue at water level to white and brown at hill tops. The terrain features that are clearly visible in this image include tributaries of the Sao Francisco, the dark-blue branch-like features visible from top right to bottom left, and on the left edge of the image, and hills rising up from the valley floor. The San Francisco River is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, forestation and human influences on ecosystems. This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning. http://photojournal.jpl.nasa.gov/catalog/PIA02700

Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory

USGS Publications Warehouse

Iavorivska , Lidiia; Boyer, Elizabeth W.; Grimm, Jeffrey W.; Miller, Matthew P.; DeWalle, David R.; Davis, Kenneth J.; Kaye, Margot W.

2017-01-01

Organic compounds are removed from the atmosphere and deposited to the earth's surface via precipitation. In this study, we quantified variations of dissolved organic carbon (DOC) in precipitation during storm events at the Shale Hills Critical Zone Observatory, a forested watershed in central Pennsylvania (USA). Precipitation samples were collected consecutively throughout the storm during 13 events, which spanned a range of seasons and synoptic meteorological conditions, including a hurricane. Further, we explored factors that affect the temporal variability by considering relationships of DOC in precipitation with atmospheric and storm characteristics. Concentrations and chemical composition of DOC changed considerably during storms, with the magnitude of change within individual events being comparable or higher than the range of variation in average event composition among events. While some previous studies observed that concentrations of other elements in precipitation typically decrease over the course of individual storm events, results of this study show that DOC concentrations in precipitation are highly variable. During most storm events concentrations decreased over time, possibly as a result of washing out of the below-cloud atmosphere. However, increasing concentrations that were observed in the later stages of some storm events highlight that DOC removal with precipitation is not merely a dilution response. Increases in DOC during events could result from advection of air masses, local emissions during breaks in precipitation, or chemical transformations in the atmosphere that enhance solubility of organic carbon compounds. This work advances understanding of processes occurring during storms that are relevant to studies of atmospheric chemistry, carbon cycling, and ecosystem responses.

Stargazing at 'Husband Hill Observatory' on Mars

NASA Technical Reports Server (NTRS)

2005-01-01

NASA's Mars Exploration Rover Spirit continues to take advantage of extra solar energy by occasionally turning its cameras upward for night sky observations. Most recently, Spirit made a series of observations of bright star fields from the summit of 'Husband Hill' in Gusev Crater on Mars. Scientists use the images to assess the cameras' sensitivity and to search for evidence of nighttime clouds or haze. The image on the left is a computer simulation of the stars in the constellation Orion. The next three images are actual views of Orion captured with Spirit's panoramic camera during exposures of 10, 30, and 60 seconds.

Because Spirit is in the southern hemisphere of Mars, Orion appears upside down compared to how it would appear to viewers in the Northern Hemisphere of Earth. 'Star trails' in the longer exposures are a result of the planet's rotation. The faintest stars visible in the 60-second exposure are about as bright as the faintest stars visible with the naked eye from Earth (about magnitude 6 in astronomical terms). The Orion Nebula, famous as a nursery of newly forming stars, is also visible in these images. Bright streaks in some parts of the images aren't stars or meteors or unidentified flying objects, but are caused by solar and galactic cosmic rays striking the camera's detector. Spirit acquired these images with the panoramic camera on Martian day, or sol, 632 (Oct. 13, 2005) at around 45 minutes past midnight local time, using the camera's broadband filter (wavelengths of 739 nanometers plus or minus 338 nanometers).

Integrated approach towards understanding interactions of mineral dust aerosol with warm clouds

NASA Astrophysics Data System (ADS)

Kumar, Prashant

2011-12-01

Mineral dust is ubiquitous in the atmosphere and represents a dominant type of particulate matter by mass. Dust particles can serve as cloud condensation nuclei (CCN), giant CCN (GCCN), or ice nuclei (IN), thereby, affecting cloud microphysics, albedo, and lifetime. Despite its well-recognized importance, assessments of dust impacts on clouds and climate remain highly uncertain. This thesis addresses the role of dust as CCN and GCCN with the goal of improving our understanding of dust-warm cloud interactions and their representation in climate models. Most studies to date focus on the soluble fraction of aerosol particles when describing cloud droplet nucleation, and overlook the interactions of the hydrophilic insoluble fraction with water vapor. A new approach to include such interactions (expressed by the process of water vapor adsorption) is explored, by combining multilayer Frenkel-Halsey-Hill (FHH) physical adsorption isotherm and curvature (Kelvin) effects. The importance of adsorption activation theory (FHH-AT) is corroborated by measurements of CCN activity of mineral aerosols generated from clays, calcite, quartz, and desert soil samples from Northern Africa, East Asia/China, and Northern America. A new aerosol generation setup for CCN measurements was developed based on a dry generation technique capable of reproducing natural dust aerosol emission. Based on the dependence of critical supersaturation with particle dry diameter, it is found that the FHH-AT is a better framework for describing fresh (and unprocessed) dust CCN activity than the classical Kohler theory (KT). Ion Chromatography (IC) measurements performed on fresh regional dust samples indicate negligible soluble fraction, and support that water vapor adsorption is the prime source of CCN activity in the dust. CCN measurements with the commonly used wet generated mineral aerosol (from atomization of a dust aqueous suspension) are also carried out. Results indicate that the method is subject to biases as it generates a bimodal size distribution with a broad range of hygroscopicity. It is found that smaller particles generated in the more hygroscopic peak follow CCN activation by KT, while the larger peak is less hydrophilic with activation similar to dry generated dust that follow FHH-AT. Droplet activation kinetics measurements demonstrate that dry generated mineral aerosol display retarded activation kinetics with an equivalent water vapor uptake coefficient that is 30 - 80% lower relative to ammonium sulfate aerosol. Wet generated mineral aerosols, however, display similar activation kinetics to ammonium sulfate. These results suggest that at least a monolayer of water vapor (the rate-limiting step for adsorption) persists during the timescale of aerosol generation in the experiment, and questions the atmospheric relevance of studies on mineral aerosol generated from wet atomization method. A new parameterization of cloud droplet formation from insoluble dust CCN for regional and global climate models is also developed. The parameterization framework considers cloud droplet formation from dust CCN activating via FHH-AT, and soluble aerosol with activation described through KT. The parameterization is validated against a numerical parcel model, agreeing with predictions to within 10% (R2 ˜ 0.98). The potential role of dust GCCN activating by FHH-AT within warm stratocumulus and convective clouds is also evaluated. It is found that under pristine aerosol conditions, dust GCCN can act as collector drops with implications to dust-cloud-precipitation linkages. Biases introduced from describing dust GCCN activation by KT are also addressed. The results demonstrate that dust particles do not require deliquescent material to act as CCN in the atmosphere. Furthermore, the impact of dust particles as giant CCN on warm cloud and precipitation must be considered. Finally, the new parameterization of cloud droplet formation can be implemented in regional and global models providing an improved treatment of mineral aerosol on clouds and precipitation. The new framework is uniquely placed to address dust aerosol indirect effects on climate.

Directional Site Amplification Effect on Tarzana Hill, California

NASA Astrophysics Data System (ADS)

Graizer, V.; Shakal, A.

2003-12-01

Significantly amplified ground accelerations at the Tarzana Hill station were recorded during the 1987 Mw 5.9 Whittier Narrows and the 1994 Mw 6.7 Northridge earthquakes. Peak horizontal ground acceleration at the Tarzana station during the 1999 Mw 7.1 Hector Mine earthquake was almost twice as large as the accelerations recorded at nearby stations. The Tarzana site was drilled to a depth of 100 m. A low shear-wave velocity near the surface of 100 m/sec increasing to near 750 m/sec at 100 m depth was measured. The 20 m high hill was found to be well drained with a water table near 17 m. Modelo formation (extremely weathered at the surface to fresh at depth) underlies the hill. The subsurface geology and velocities obtained allow classification of this location as a soft-rock site. After the Northridge earthquake the California Strong Motion Instrumentation Program significantly increased instrumentation at Tarzana to study the unusual site amplification effect. Current instrumentation at Tarzana consists of an accelerograph at the top of Tarzana hill (Tarzana - Cedar Hill B), a downhole instrument at 60 m depth, and an accelerograph at the foot of the hill (Tarzana - Clubhouse), 180 m from the Cedar Hill B station. The original station, Tarzana - Cedar Hill Nursery A, was lost in 1999 due to construction. More than twenty events, including the Hector Mine earthquake, were recorded by all these instruments at Tarzana. Comparison of recordings and response spectra demonstrates strong directional resonance on the top of the hill in a direction perpendicular to the strike of the hill in the period range from 0.04 to 0.8 sec (1.2 to 25 Hz). There is practically no amplification from the bottom to the top of the hill for the component parallel to the strike of the hill. In contrast to accelerations recorded during the Hector Mine earthquake (high frequency part of seismic signal), displacements (relatively low frequency part of seismic signal) demonstrate almost no site amplification from the bottom of the hole to the surface at periods greater than 1.5 sec, in either direction. The directional effect at Tarzana hill seems to be azimuth dependent. Relatively higher amplification at the perpendicular component is produced for the earthquake sources located north of the station. We were not able to see any differences in hill response before and after development (a relatively small part of the hill was developed). The source of the site amplification that produces large motions at Tarzana is still under investigation with "the usual suspects" like topography and shear wave velocity profile not providing the explanation. New data recorded at Tarzana in recent years clearly show that the Tarzana effect is a very localized high-frequency effect observed only at the top of the hill. Drilling at Tarzana was co-funded by CSMIP and by the National Science Foundation through the Resolution of Site Response Issues from the Northridge Earthquake Project (ROSRINE).

Snow in Italy

NASA Image and Video Library

2012-02-24

NASA image acquired February 24, 2012 By late February, 2012, the great European cold wave had begun to loosen its frigid grip, but significant snow still remained in the region. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite captured this true-color image of snow in Italy on February 24 at 12:35 UTC (1:30 p.m. local time). In the north of the image, bright white clouds blanket the region in a broad arc. Snow, which tends to be generally less bright that clouds, covers the Alps in the north of Italy. The Apennine Mountains, which form the backbone of the Italian peninsula, also carry a blanket of snow. Although clouds and snow can, at times, be distinguished visually in a true-color image, sometimes they can appear very similar. When it is important to clearly define snow from cloud, false color images are often helpful. Rome, which can be seen as a gray smudge on the southwestern coast of the peninsula, recorded highs of a spring-like 50°F the day this image was captured, but earlier in the month the temperatures dove as low as 26°F on February 5. During that cold snap a rare intense snowfall blanketed Rome, causing the closure of the Colosseum, the Roman Forum and the Palatine Hill due to concerns of the risk of icy footing for tourists, and roads became impassible. Further north, temperatures plummeted to −21 °C (−6 °F) on 7 February. On February 11, news media reported over 2 meters (6.5 feet) of snow had fallen in Urbino, a walled town situated on a high sloping hillside on the eastern side of the Apennine Mountains. That same snowfall cut access to many remote towns in the Apennines, blocking roads and trapping some people in the homes. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Is the semi-direct effect for smoke overlying stratocumulus clouds overrated? Circulation variability and radiative impacts Reconsidered for the southeast Atlantic

NASA Astrophysics Data System (ADS)

Zuidema, P.; Adebiyi, A. A.; Abel, S.

2013-12-01

Smoke produced by seasonal biomass burning in the southwestern African savannah can be advected westward over the Atlantic Ocean, where it mostly overlies a major planetary stratocumulus deck. Shortwave absorption by the smoke warms the atmosphere, stabilizing it, thereby reducing cloud-top entrainment and encouraging cloud thickening (the semi-direct effect). Associated dynamical and moisture effects that may be convoluted with the semi-direct effect have received less attention, and are examined here. Radiosondes at their original resolution are available almost daily from the remote St. Helena Island (15.9oS, 5.6oW), from 2000 through 2012. These are combined with MODIS fine-mode aerosol optical depth (AODf), and composited into pristine and polluted days for the September-October months. Increases in AODf are associated with increases in 750-500 hPa moisture content, often capped by sharply defined temperature and moisture inversions. These corroborate similar associations evident in SAFARI-2000 data. The composite-mean additional moisture of ~2.2 g kg-1 produces a diurnal-mean shortwave heating rate of ~ 0.2 K day-1 in addition to that from smoke. Similarly-composited ERA-Interim Reanalysis profiles match the radiosonde composites more closely than do those based on MERRA or NCEP Reanalyses. ERA-Interim spatial composites show that the polluted conditions are associated with a stronger mid-level anticyclone over southern Africa, facilitating the westward and (offshore) southward transport of both smoke and moisture. The shallower surface-based south Atlantic anticyclone shifts to east, strengthening the low-level coastal jet exiting into the stratocumulus deck, and enhancing warm temperature advection above the main stratocumulus deck. This increases the lower tropospheric stability (θ800-θ1000) and enhances the surface fluxes, strengthening the stratocumulus deck. Thus, the dynamics encouraging smoke transport and the additional shortwave absorption by moisture act in concert with the semi-direct effect to increase the cloud fraction and thicken the clouds. The associations between smoke, moisture and circulation highlight the difficulty of distinguishing aerosol effects on the Atlantic stratocumulus deck from meteorological effects.The uncertainties inherent to the realistic modeling of the smoke, cloud, their interactions and their climatic effects motivate a field deployment, ONFIRE, proposed to the southeast Atlantic in 2016, that will also be discussed.

27 CFR 9.190 - Red Hill Douglas County, Oregon.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., Oregon. 9.190 Section 9.190 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

27 CFR 9.190 - Red Hill Douglas County, Oregon.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., Oregon. 9.190 Section 9.190 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

27 CFR 9.190 - Red Hill Douglas County, Oregon.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., Oregon. 9.190 Section 9.190 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... Areas § 9.190 Red Hill Douglas County, Oregon. (a) Name. The name of the viticultural area described in this section is “Red Hill Douglas County, Oregon”. For purposes of part 4 of this chapter, “Red Hill...

40 CFR 81.214 - Black Hills-Rapid City Intrastate Air Quality Control Region.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Black Hills-Rapid City Intrastate Air... Air Quality Control Regions § 81.214 Black Hills-Rapid City Intrastate Air Quality Control Region. The Rapid City Intrastate Air Quality Control Region (South Dakota) has been renamed the Black Hills-Rapid...

40 CFR 81.214 - Black Hills-Rapid City Intrastate Air Quality Control Region.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Black Hills-Rapid City Intrastate Air... Air Quality Control Regions § 81.214 Black Hills-Rapid City Intrastate Air Quality Control Region. The Rapid City Intrastate Air Quality Control Region (South Dakota) has been renamed the Black Hills-Rapid...

The timber resources of the Ohio Hill Country

Treesearch

Paul S. DeBald; Roger E. McCay

1969-01-01

This report presents 1967 forest resource statistics for the Hill Country-Ohio's portion of Appalachia. The Hill Country comprises 28 counties, which were divided into three geographic sampling units for this survey. The Hill Country of the 1952 Ohio forest survey contained 26 of these counties. The additional Appalachia counties are Brown and Clermont in the...

76 FR 35101 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-16

... Mobridge, SD, Mobridge Muni, Takeoff Minimums and Obstacle DP, Amdt 1 Spearfish, SD, Black Hills-Clyde Ice Field, GPS RWY 12, Orig-D, CANCELLED Spearfish, SD, Black Hills-Clyde Ice Field, NDB-A, Amdt 1 Spearfish, SD, Black Hills-Clyde Ice Field, RNAV (GPS) RWY 13, Orig Spearfish, SD, Black Hills-Clyde Ice Field...

Structure, stratigraphy, and origin of Husband Hill, Columbia Hills, Gusev Crater, Mars

USGS Publications Warehouse

McCoy, T.J.; Sims, M.; Schmidt, M.E.; Edwards, L.; Tornabene, L.L.; Crumpler, L.S.; Cohen, B. A.; Soderblom, L.A.; Blaney, D.L.; Squyres, S. W.; Arvidson, R. E.; Rica, J.W.; Treguier, E.; d'Uston, C.; Grant, J. A.; McSween, H.Y.; Golombek, M.P.; Haldemann, A.F.C.; de Souza, P.A.

2008-01-01

The strike and dip of lithologic units imaged in stereo by the Spirit rover in the Columbia Hills using three-dimensional imaging software shows that measured dips (15-32??) for bedding on the main edifice of the Columbia Hill are steeper than local topography (???8-10??). Outcrops measured on West Spur are conformable in strike with shallower dips (7-15??) than observed on Husband Hill. Dips are consistent with observed strata draping the Columbia Hills. Initial uplift was likely related either to the formation of the Gusev Crater central peak or ring or through mutual interference of overlapping crater rims. Uplift was followed by subsequent draping by a series of impact and volcaniclastic materials that experienced temporally and spatially variable aqueous infiltration, cementation, and alteration episodically during or after deposition. West Spur likely represents a spatially isolated depositional event. Erosion by a variety of processes, including mass wasting, removed tens of meters of materials and formed the Tennessee Valley primarily after deposition. This was followed by eruption of the Adirondack-class plains basalt lava flows which embayed the Columbia Hills. Minor erosion, impact, and aeolian processes have subsequently modified the Columbia Hills. Copyright 2008 by the American Geophysical Union.

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.

Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumedmore » that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.« less

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

DOE PAGES

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; ...

2017-06-19

Covering 71% of the Earth’s surface, oceans represent a significant global source of atmospheric aerosols. The size and composition of sea spray aerosols (SSA) affect their ability to serve as cloud seeds and thus understanding the factors controlling their composition is critical to predicting their impact on clouds and climate. SSA particles have been shown to be an external mixture of particles with different compositions. Film and jet drop production mechanisms ultimately determine the individual particle compositions which are comprised of an array of salt/organic mixtures ranging from pure sea salt to nearly pure organic particles. It is often assumedmore » that the majority of submicron SSA are formed by film drops produced from bursting hydrophobic organic-rich bubble film caps at the sea surface, and in contrast, jet drops are postulated to produce larger supermicron particles from underlying seawater comprised largely of salts and water soluble organic species. However, here we show that jet drops produced by bursting sub-100 m bubbles account for up to 40 % of all submicron particles. They have distinct chemical compositions, organic volume fractions and ice nucleating activities from submicron film drops. Thus a substantial fraction of submicron particles will not necessarily be controlled by the composition of the sea surface microlayer as has been assumed in many studies. This finding has significant ramifications for the size-resolved mixing states of SSA particles which must be taken into consideration when accessing SSA impacts on clouds.« less

The role of jet and film drops in controlling the mixing state of submicron sea spray aerosol particles

PubMed Central

Wang, Xiaofei; Deane, Grant B.; Moore, Kathryn A.; Ryder, Olivia S.; Stokes, M. Dale; Beall, Charlotte M.; Santander, Mitchell V.; Burrows, Susannah M.; Sultana, Camille M.; Prather, Kimberly A.

2017-01-01

The oceans represent a significant global source of atmospheric aerosols. Sea spray aerosol (SSA) particles comprise sea salts and organic species in varying proportions. In addition to size, the overall composition of SSA particles determines how effectively they can form cloud droplets and ice crystals. Thus, understanding the factors controlling SSA composition is critical to predicting aerosol impacts on clouds and climate. It is often assumed that submicrometer SSAs are mainly formed by film drops produced from bursting bubble-cap films, which become enriched with hydrophobic organic species contained within the sea surface microlayer. In contrast, jet drops formed from the base of bursting bubbles are postulated to mainly produce larger supermicrometer particles from bulk seawater, which comprises largely salts and water-soluble organic species. However, here we demonstrate that jet drops produce up to 43% of total submicrometer SSA number concentrations, and that the fraction of SSA produced by jet drops can be modulated by marine biological activity. We show that the chemical composition, organic volume fraction, and ice nucleating ability of submicrometer particles from jet drops differ from those formed from film drops. Thus, the chemical composition of a substantial fraction of submicrometer particles will not be controlled by the composition of the sea surface microlayer, a major assumption in previous studies. This finding has significant ramifications for understanding the factors controlling the mixing state of submicrometer SSA particles and must be taken into consideration when predicting SSA impacts on clouds and climate. PMID:28630346

The origin of Mauna Loa's Nīnole Hills: Evidence of rift zone reorganization

USGS Publications Warehouse

Zurek, Jeffrey; Williams-Jones, Glyn; Trusdell, Frank A.; Martin, Simon

2015-01-01

In order to identify the origin of Mauna Loa volcano's Nīnole Hills, Bouguer gravity was used to delineate density contrasts within the edifice. Our survey identified two residual anomalies beneath the Southwest Rift Zone (SWRZ) and the Nīnole Hills. The Nīnole Hills anomaly is elongated, striking northeast, and in inversions both anomalies merge at approximately −7 km above sea level. The positive anomaly, modeled as a rock volume of ~1200 km3 beneath the Nīnole Hills, is associated with old eruptive vents. Based on the geologic and geophysical data, we propose that the gravity anomaly under the Nīnole Hills records an early SWRZ orientation, now abandoned due to geologically rapid rift-zone reorganization. Catastrophic submarine landslides from Mauna Loa's western flank are the most likely cause for the concurrent abandonment of the Nīnole Hills section of the SWRZ. Rift zone reorganization induced by mass wasting is likely more common than currently recognized.

Seeing mountains in mole hills: geographical-slant perception

NASA Technical Reports Server (NTRS)

Proffitt, D. R.; Creem, S. H.; Zosh, W. D.; Kaiser, M. K. (Principal Investigator)

2001-01-01

When observers face directly toward the incline of a hill, their awareness of the slant of the hill is greatly overestimated, but motoric estimates are much more accurate. The present study examined whether similar results would be found when observers were allowed to view the side of a hill. Observers viewed the cross-sections of hills in real (Experiment 1) and virtual (Experiment 2) environments and estimated the inclines with verbal estimates, by adjusting the cross-section of a disk, and by adjusting a board with their unseen hand to match the inclines. We found that the results for cross-section viewing replicated those found when observers directly face the incline. Even though the angles of hills are directly evident when viewed from the side, slant perceptions are still grossly overestimated.

Drought in the Black Hills

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Annotated Color-Coded Map

Despite good rainfall and record-setting snowstorms in the spring of 2005, most of northeastern Wyoming, the Black Hills, and western South Dakota remain in the midst of a severe drought. This set of images and maps from NASA's Multi-angle Imaging SpectroRadiometer (MISR) contrast the appearance of the Black Hills region of northwestern South Dakota on July 12, 2000 (left column), with views acquired four years later, on July 14, 2004 (right column). The natural-color images along the top are from MISR's nadir (downward-looking) camera. The browning that appears in 2004 compared with 2000 indicates that the vigor of green vegetation was significantly diminished in 2004.

The color-coded maps (along the bottom) provide a quantitative measurement of the sunlight reflected from these surfaces, and the loss of sunlight-absorbing vegetation between the 2000 and 2004 dates. As the vegetation faded with the drought, the albedo at the surface increased. Albedo measures the fraction of incident sunlight that is reflected by a surface, and can vary between zero (if all the incident sunlight is absorbed and none is reflected) and one (if all sunlight is reflected and none is absorbed). Dense forest has a low albedo; bright desert, snow and clouds, have a high albedo. Here, albedo is provided for the wavelengths of sunlight that plants use for photosynthesis (400 - 700 nanometers). This measurement is known as the albedo for Photosynthetically Active Radiation (PAR). Surfaces with greater absorption of PAR appear here in blue hues, whereas surfaces with lower absorption appear as green, yellow, orange or red. Black pixels indicate areas where albedo could not be derived, usually due to the presence of clouds. In July 2004, low albedo areas (blue pixels) are notably reduced in extent, and higher albedo areas (yellow, orange and red pixels) have increased.

Because incoming sunlight is scattered by tiny particles in the atmosphere, satellite measurements of albedo and other surface properties must correct for the effects of the intervening atmosphere. These albedo retrievals make use of MISR's simultaneously derived aerosol properties to make these corrections. The multiangular nature of MISR data is also used to account for the fact that most surfaces reflect sunlight into all upward directions, with intensities that vary with angle of view.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82o north and 82o south latitude. This image area covers about 243 kilometers by 259 kilometers. These data products were generated from a portion of the imagery acquired during Terra orbits 3020 and 24325 and utilize data from within blocks 54 to 56 within World Reference System-2 paths 33 and 34.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

Aircraft observations of the physical and radiative properties of biomass aerosol particles during SAFARI-2000.

NASA Astrophysics Data System (ADS)

Osborne, S. R.; Haywood, J. M.

2001-12-01

An initial analysis will be shown from the ~80 h of data collected between 2--18 September 2000 by the UK Met Office C-130 aircraft during the dry season campaign of the Southern African Regional Science Initiative (SAFARI-2000). The talk will concentrate on the physical and optical properties of the biomass aerosol. The evolution of the particle size spectrum and its optical properties at emission and after ageing will be shown. The vertical distribution of the biomass plume over the land and sea will be compared in view of the local meteorology. A generalised three log-normal model is shown to represent aged biomass aerosol over the sea areas, both in terms of the number and mass particle size spectra, but also derived optical properties (e.g. asymmetry factor, single scatter albedo (ω 0) and extinction coefficient) as calculated using Mie theory and appropriate refractive indices. ω 0 was determined independently using a particle soot absorption photometer (giving the absorption coefficient at a wavelength of 0.567 μ m) and a nephelometer (giving the scattering coefficients at 0.45, 0.55 and 0.65 μ m). Good agreement was found between the measurements and those obtained from the Mie calculations and observed size distributions. A typical value of ω 0 at 0.55 μ m for aged biomass aerosol was 0.90. The radiative properties of the biomass aerosol over both land and sea will be summarised. Stratocumulus cloud was present on some of the days over the sea and the surprising lack of interaction between the elevated biomass plume (containing significant levels of cloud condensation nuclei) and the cloud capping the marine boundary layer will be illustrated. Using the cloud-free and cloudy case studies we can begin to elucidate the levels of direct and indirect forcing of the biomass aerosol on a regional scale. >http://www.mrfnet.demon.co.uk/africa/SAFARI2000.htm

40 CFR 81.327 - Montana.

Code of Federal Regulations, 2010 CFR

2010-07-01

... County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part) excluding... Golden Valley County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part... Unclassifiable/Attainment Granite County. Unclassifiable/Attainment Hill County Unclassifiable/Attainment...

40 CFR 81.327 - Montana.

Code of Federal Regulations, 2011 CFR

2011-07-01

... County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part) excluding... Golden Valley County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part... Unclassifiable/Attainment Granite County. Unclassifiable/Attainment Hill County Unclassifiable/Attainment...

Multi-scale habitat use of male ruffed grouse in the Black Hills National Forest

Treesearch

Cassandra L. Mehls; Kent C. Jensen; Mark A. Rumble; Michael C. Wimberly

2014-01-01

Ruffed grouse (Bonasa umbellus) are native upland game birds and a management indicator species (MIS) for aspen (Populus tremuloides) in the Black Hills National Forest (Black Hills). Our objective was to assess resource selection of male ruffed grouse to identify the most appropriate scale to manage for aspen and ruffed grouse in the Black Hills. During spring 2007...

Low-velocity zone and topography as a source of site amplification effect on Tarzana hill, California

USGS Publications Warehouse

Graizer, V.

2009-01-01

Tarzana station is located in the foothills of the Santa Monica Mountains in California near the crest of a low (<20 m) natural hill with gentle slopes. The hill is about 500 m in length by 130 m in width and is formed of extremely weathered shale at the surface to fresh at depth. Average S-wave is about 250 m/s in the top 17-18 m, and S- and P-wave velocities significantly increase below this depth. According to the NEHRP classification based on VS30???300 m/s it is a site class D. Strong-motion instrumentation at Tarzana consisted of an accelerograph at the top of the hill, a downhole instrument at 60 m depth, and an accelerograph at the base of the hill. More than 20 earthquakes were recorded by at least three instruments at Tarzana from 1998 till 2003. Comparisons of recordings and Fourier spectra indicate strong directional resonance in a direction perpendicular to the strike of the hill. The dominant peaks in ground motion amplification on the top of the hill relative to the base are at frequencies ???3.6 and 8-9 Hz for the horizontal components. Our hypothesis is that the hill acts like a wave trap. This results in an amplification at predominant frequencies f=V/4 h (h is layer's thickness) at f???3.6 Hz for S-waves (using average VS17=246 m/s and h=17 m) and f???7.9 Hz for P-waves (using average VP17=535 m/s and h=17 m). As was shown by Bouchon and Barker [Seismic response of a hill: the example of Tarzana, California. Bull Seism Soc Am 1996;86(1A):66-72], topography of this hill amplifies and polarizes ground motion in the frequency range of 3-5 Hz. Hill acts as a magnifying polarizing glass: It polarizes ground motion in the direction perpendicular to the strike of the hill and also amplifies ground motions that had been also amplified by a low-velocity layer.

40 CFR 81.327 - Montana.

Code of Federal Regulations, 2013 CFR

2013-07-01

... County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part) excluding... Golden Valley County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part.... Golden Valley County Unclassifiable/Attainment. Granite County Unclassifiable/Attainment. Hill County...

40 CFR 81.327 - Montana.

Code of Federal Regulations, 2012 CFR

2012-07-01

... County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part) excluding... Golden Valley County Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part.... Golden Valley County Unclassifiable/Attainment. Granite County Unclassifiable/Attainment. Hill County...

Hypotheses of Spatial Stock Structure in Orange Roughy Hoplostethus atlanticus Inferred from Diet, Feeding, Condition, and Reproductive Activity

PubMed Central

Dunn, Matthew R.; Forman, Jeffrey S.

2011-01-01

We evaluate hypotheses for meso-scale spatial structure in an orange roughy (Hoplostethus atlanticus) stock using samples collected during research trawl surveys off the east coast of New Zealand. Distance-based linear models and generalised additive models were used to identify the most significant biological, environmental, and temporal predictors of variability in diet, proportion of stomachs containing prey, standardised weight of prey, fish somatic weight, fish total weight, and reproductive activity. The diet was similar to that observed elsewhere, and varied with ontogeny, depth, and surface water temperature. Smaller sized and female orange roughy in warmer bottom water were most likely to contain food. Fish condition and reproductive activity were highest at distances more than 20 km from the summit of the hills. Trawl survey catches indicated greater orange roughy densities in hill strata, suggesting hill habitat was favoured. However, analyses of feeding, condition, and reproductive activity indicated hill fish were not superior, despite fish densities on hills being reduced by fishing which, in principle, should have reduced intra-specific competition for food and other resources. Hypotheses for this result include: (1) fish in relatively poor condition visit hills to feed and regain condition and then leave, or (2) commercial fishing has disturbed feeding aggregations and/or caused habitat damage, making fished hills less productive. Mature orange roughy were observed on both flat and hill habitat during periods outside of spawning, and if this spatial structure was persistent then a proportion of the total spawning stock biomass would remain unavailable to fisheries targeting hills. Orange roughy stock assessments informed only by data from hills may well be misleading. PMID:22069464

Stratigraphy and depositional environments of Fox Hills Formation (Late Cretaceous), Williston basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, D.J.

The Fox Hills Formation (Late Cretaceous, Maestrichtian) was investigated where it crops out along the southern flank of the Williston basin and in the subsurface over the central portion of the basin, using 300 well logs. The formation is conformable and gradational with the underlying Pierre formation and can be either conformable or unconformable with the overlying Hell Creek Formation. The Fox Hills Formation is younger, thicker, and stratigraphically more complex to the east and is comprised of marginal marine sediments deposited during the final Cretaceous regression. To the west, the Fox Hills Formation is an upward-coarsening unit generally 30more » to 45 m thick and usually contains three members: from the base, Trail City, Timber Lake, and Colgate. The lower Fox Hills (Trail City, Timber Lake) is generally dominated by hummocky bedding and contains a variety of trace fossils, most notably Ophiomorpha. The upper Fox Hills (Colgate), where present, is characterized by cross-bedding. To the east, including the type area, the section is generally 80 to 100 m thick and contains four members: from the base, Trail City, Timber Lake, Iron Lightning (Colgate and Bullhead lithofacies), and Linton. In contrast to the section in the west, this section is as much as three times thicker, contains abundant body fossils, generally lacks hummocky bedding, and contains the Bullhead and Linton strata. In the west, the strata represent lower shoreface deposits, predominantly of storm origin (lower Fox Hills), overlain by upper shoreface and fluvial deposits (upper Fox Hills). In the east, the lower Fox Hills contains deposits of the lower shoreface (Trail City) and a barrier bar complex (Timber Lake), overlain by the deltaic deposits of the upper Fox Hills (Iron Lightning, Linton).« less

Both sides of the Atlantic Ocean are visible from Apollo 8 spacecraft

NASA Image and Video Library

1968-12-22

AS08-16-2588 (21-27 Dec. 1968) --- Both sides of the Atlantic Ocean are visible in this view from Apollo 8 spacecraft. (Hold picture with Earth at bottom left). The large, most prominent land mass is the bulge of West Africa. The portion of Africa near the equator is dark and cloudy, but the more northerly portions are clear, showing the prominent cape at Dakar and the Senegal River in Senegal; Cap Blanc; the Adrar Plateau in Mauretania; the wide expanse of desert in Algeria and Spanish Sahara; and the far edge, the Atlas and Anti-Atlas Mountains in Morocco. Clouds cover the eastern coast of South America, southward from Surinam and Guyana to near the city of Salvador, Brazil. The view was photographed following trans-lunar insertion.

Instrument Development of Real Time Holographic Water Drop Size Measurement System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springston, Stephen

2007-02-09

BNL participated with multiple correspondences with Physical Optics Corporation (POC) on the design considerations of an airbome instrument. A pod for extemal deployment ofthe POC unit on the DOE Research Aircraft Facility (RAF), an instrumented, Grumman G-1 aircraft was loaned to POC. BNL proposed evaluation flight tests between the POC unit and the BNL Cloud Aerosol Probe Spectrometer (CAPS) as a reference method. BNL's involvement is described in the semi-annual report ofPOC to DOE. Because of unanticipated technical and engineering difficulties, POC was unable to fit their instrument into an aircraft pod. As a result they are now focusing onmore » a ground-based version first. A prototype laboratory version of the Real-Time Holographic Water Drop Size Measurement (WDSM) System has been constructed.« less

Abyssal hills: Influence of topography on benthic foraminiferal assemblages

NASA Astrophysics Data System (ADS)

Stefanoudis, Paris V.; Bett, Brian J.; Gooday, Andrew J.

2016-11-01

Abyssal plains, often thought of as vast flat areas, encompass a variety of terrains including abyssal hills, features that constitute the single largest landscape type on Earth. The potential influence on deep-sea benthic faunas of mesoscale habitat complexity arising from the presence of abyssal hills is still poorly understood. To address this issue we focus on benthic foraminifera (testate protists) in the >150-μm fraction of Megacorer samples (0-1 cm layer) collected at five different sites in the area of the Porcupine Abyssal Plain Sustained Observatory (NE Atlantic, 4850 m water depth). Three sites are located on the tops of small abyssal hills (200-500 m elevation) and two on the adjacent abyssal plain. We examined benthic foraminiferal assemblage characteristics (standing stock, diversity, composition) in relation to seafloor topography (hills vs. plain). Density and rarefied diversity were not significantly different between the hills and the plain. Nevertheless, hills do support a higher species density (i.e. species per unit area), a distinct fauna, and act to increase the regional species pool. Topographically enhanced bottom-water flows that influence food availability and sediment type are suggested as the most likely mechanisms responsible for these differences. Our findings highlight the potential importance of mesoscale heterogeneity introduced by relatively modest topography in regulating abyssal foraminiferal diversity. Given the predominance of abyssal hill terrain in the global ocean, we suggest the need to include faunal data from abyssal hills in assessments of abyssal ecology.

Sidescan Sonar Imagery of the Escanaba Trough, Southern Gorda Ridge, Offshore Northern California

USGS Publications Warehouse

Ross, Stephanie L.; Zierenberg, Robert A.

2009-01-01

This map features sidescan imagery of the northern Escanaba (NESCA) site at the Escanaba Trough, southern Gorda Ridge, offshore northern California. The Escanaba Trough, a largely sediment-covered seafloor spreading center, contains at least six large massive sulfide deposits. It is a slow spreading center (2.5 cm/yr) with axial depths locally exceeding 3,300 m. Discrete igneous centers occur at 5- to 10-km intervals along this slow-spreading ridge. Basaltic magma intrudes the sediment fill of the axial valley, creating uplifted sediment hills, and, in some areas, erupts onto the sea floor. Large massive sulfide deposits occur along the margins of the uplifted sediment hills. The only active hydrothermal system is located on Central Hill where 220 deg C fluids construct anhydrite chimneys on pyrrhotite-rich massive sulfide mounds (Campbell and others, 1994). Central Hill is bounded by both ridge-parallel basement faults and a concentric set of faults that rim the top of the hill and may be associated with sill intrusion. Central Hill was one of the primary drill sites for Ocean Drilling Program (ODP) Leg 169. The sidescan sonar data (mosaics A, B, C, D) were collected aboard the National Oceanic and Atmospheric Administration (NOAA) research vessel Discoverer in the summer of 1996 with a 60-kHz system towed 100 to 200 m above the sea floor. Major faults and contacts are interpreted from the sidescan mosaics and 4.5-kHz seismic profiles collected simultaneously, as well as from previously conducted camera transects and submersible dives. The seismic profiles (lines 9, 11, 13) provide high-resolution subbottom structure and stratigraphy to a depth of about 50 m. In the sidescan images (mosaics A, B, C, D), bright areas denote high-energy returns from hard reflectors such as volcanic flows, sulfide deposits, or seafloor scarps. Dark areas denote low-energy returns and generally signify relatively undisturbed surface sediment. The grid lines mark one-minute intervals of latitude and longitude. The large sidescan sonar image (mosaic A) is centered on the NESCA igneous center. The spreading axis is flanked on either side by uplifted, sediment-covered terraces that show relatively continuous and undisturbed turbiditic sediment. These terraces bound the 4- to 5-km-wide neotectonic zone that is characterized by more closely spaced, small offset (<20 m) faults, volcanic flows (brightest area of backscatter), and areas where the seismic layering of the turbidites has been partially to completely disrupted by the intrusion of basaltic sills. The most prominent bathymetric features are the three uplifted sediment hills: Central Hill, Southwest Hill, and an unnamed uplifted hill to the north. These features are interpreted to be uplifted above large-volume basaltic intrusions emplaced near the basalt/sediment interface. Southwest Hill is adjacent to the zone of most recent faulting. This hill no longer retains the circular shape of the other hills due to slumps (lines 9, 11), which may have failed along faults related to the most recent spreading. Central Hill is interpreted to be the most recently uplifted sediment hill based on the morphology of the hill and the presence of an active hydrothermal system. The generally continuous area of volcanic basalt flow east of Central Hill appears as a distinct, bright sonar reflector stretching for approximately 6 km along axis (red contact on mosaic A). This flow may be related to the intrusion that is presumed to have uplifted Central Hill. Submersible observations indicate that lava flowed around the sediment hills and ponded against the eastern up-faulted turbidite-covered sediment terrace. Previously collected, deep-penetration seismic data indicate that the lavas overlie about 450 m of sediment (Morton and Fox, 1994). Late-stage emplacement of magma in the shallow subsurface beneath the exposed lava flow is interpreted to have domed the lava flow, forming the east-west-

78 FR 21817 - Amendment of Restricted Area R-6601; Fort A.P. Hill, VA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-12

...; Airspace Docket No. 12-AEA-7] RIN 2120-AA66 Amendment of Restricted Area R-6601; Fort A.P. Hill, VA AGENCY... limits and time of designation of restricted area R-6601, Fort A.P. Hill, VA. The U.S. Army requested... limits and increase the time of designation of restricted area R-6601, Fort A.P. Hill, VA, (77 FR 35308...

Conditioning exercises in ski jumping: biomechanical relationship of squat jumps, imitation jumps, and hill jumps.

PubMed

Lorenzetti, Silvio; Ammann, Fabian; Windmüller, Sabrina; Häberle, Ramona; Müller, Sören; Gross, Micah; Plüss, Michael; Plüss, Stefan; Schödler, Berni; Hübner, Klaus

2017-11-22

As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force-time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training.

40 CFR 81.327 - Montana.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Unclassifiable/Attainment Granite County Unclassifiable/Attainment Hill County (part)excluding Rocky Boy Indian.../Attainment Granite County Unclassifiable/Attainment Hill County (part) excluding Rocky Boy Indian Reservation.../Attainment. Granite County Unclassifiable/Attainment. Hill County Unclassifiable/Attainment. Jefferson County...

Skating down a steeper slope: Fear influences the perception of geographical slant

PubMed Central

Stefanucci, Jeanine K.; Proffitt, Dennis R.; Clore, Gerald L.; Parekh, Nazish

2008-01-01

Conscious awareness of hill slant is overestimated, but visually guided actions directed at hills are relatively accurate. Also, steep hills are consciously estimated to be steeper from the top as opposed to the bottom, possibly because they are dangerous to walk down. In the present study, participants stood at the top of a hill on either a skateboard or a wooden box of the same height. They gave three estimates of the slant of the hill: a verbal report, a visually matched estimate, and a visually guided action. Fear of descending the hill was also assessed. Those participants that were scared (by standing on the skateboard) consciously judged the hill to be steeper relative to participants who were unafraid. However, the visually guided action measure was accurate across conditions. These results suggest that our explicit awareness of slant is influenced by the fear associated with a potentially dangerous action. “[The phobic] reported that as he drove towards bridges, they appeared to be sloping at a dangerous angle.” (Rachman and Cuk 1992 p. 583). PMID:18414594

Stable Low Cloud Phase II: Nocturnal Event Study

NASA Technical Reports Server (NTRS)

Bauman, William H., III; Barrett, Joe, III

2007-01-01

This report describes the work done by the Applied Meteorology Unit (AMU) in developing a database of nights that experienced rapid (< 90 minutes) low cloud formation in a stable atmosphere, resulting in ceilings at the Shuttle Landing Facility (TTS) that violated Space Shuttle Flight Rules (FR). This work is the second phase of a similar AMU task that examined the same phenomena during the day. In the first phase of this work, the meteorological conditions favoring the rapid formation of low ceilings include the presence of any inversion below 8000 ft, high relative humidity (RH) beneath the inversion and a clockwise turning of the winds from the surface to the middle troposphere (-15000 ft). The AMU compared and contrasted the atmospheric and thermodynamic conditions between nights with rapid low ceiling formation and nights with low ceilings resulting from other mechanisms. The AMU found that there was little to discern between the rapidly-forming ceiling nights and other low ceiling nights at TTS. When a rapid development occurred, the average RH below the inversions was 87% while non-events had an average RH of 79%. One key parameter appeared to be the vertical wind profile in the Cape Canaveral, FL radiosonde (XMR) sounding. Eighty-three percent of the rapid development events had veering winds with height from the surface to the middle troposphere (-15,000 ft) while 61% of the non-events had veering winds with height. Veering winds indicate a warm-advection regime, which supports large-scale rising motion and ultimately cloud formation in a moist environment. However, only six of the nights (out of 86 events examined) with low cloud ceilings had an occurrence of rapidly developing ceilings. Since only 7% rapid development events were observed in this dataset, it is likely that rapid low cloud development is not a common occurrence during the night, or at least not as common as during the day. In the AMU work on the daytime rapid low cloud development (Case and Wheeler 2005), nearly 30% of the low cloud ceiling cases investigated were identified as rapidly developing events. Forecasters at the Space Meteorology Group (SMG) issue 30 to 90 minute forecasts for low cloud ceilings at TTS to support Space Shuttle landings. Mission verification statistics have shown ceilings to be the number one forecast challenge. More specifically, forecasters at SMG are concerned with any rapidly developing clouds/ceilings below 8000 R in a stable, capped thermodynamic environment. Therefore, the AMU was tasked to examine archived events of rapid stable cloud formation resulting in ceilings below 8000 ft, and document the atmospheric regimes favoring this type of cloud development. The AMU examined the cool season months of November to March during the years of 1994-2005 for nights that had low-level inversions and rapid, stable low cloud formation that resulted in ceilings violating the Space Shuttle FR. The AMU wrote and modified existing code to identify inversions from the evening and morning XMR radiosonde during the cool season and output pertinent sounding information. They parsed all days with cloud ceilings below 8000 ft at TTS, forming a database of possible rapidly-developing low ceiling events. Nights with precipitation or noticeable fog burn-off situations were excluded from the database. Only the nighttime hours were examined for possible ceiling development events since the daytime events were examined in the first phase of this work. The report presents one sample case of rapidly-developing low cloud ceilings. The case depicts the representative meteorological and thermodynamic characteristics of such events. The case also illustrates how quickly the cloud decks can develop, sometimes forming in 30 minutes or less. The report also summarizes the composite meteorological conditions for 6 event nights with rapid low cloud ceiling formation and 80 non-events nights consisting of advection or widespread low cloud ceilings. The teorological conditions were quite similar for both the event and non-event nights, since both types of nights experienced low cloud ceilings. Both types of nights had a relatively moist environment beneath an inversion based below 8000 ft.

Earth Observations taken by Expedition 30 crewmember

NASA Image and Video Library

2011-11-22

ISS030-E-005118 (22 Nov. 2011) --- A dust plume over the Bahia Blanca, Argentina is featured in this image photographed by an Expedition 30 crew member on the International Space Station. This panoramic view of eastern Argentina and the Atlantic coastline is centered near Bahia Blanca, which is also highlighted by sun glint. The oblique view looks generally westward (and downwards) from the orbital position of the space station towards a large plume of dust blowing southeastward from the interior and over the open Atlantic Ocean. The only significant cloud cover was located offshore (upper left). Northwestern and central Argentina are subject to frequent dust storms where a combination of extensive late Pleistocene loess?fine sediments deposited by wind and typically associated with former continental glaciers?and strong, dry westerly winds descending from the Andes, known locally as the pampero sucio, combine to produce sudden and extensive clouds of the fine soil. The particular dust event illustrated by the image covers much of the province of Rio Negro and the southern parts of the provinces of La Pampa and Buenos Aires as well as the coastal waters between the Gulf of San Matias (upper left) and Bahia Blanca (center), located approximately 330 kilometers to the northeast. The area illustrated by the image includes the agriculturally productive southern Pampas plain region where it transitions to the drier, less productive low hills and valleys of northern Patagonia. A docked Russian Progress spacecraft is visible at upper right.

Variable Stars in Large Magellanic Cloud Globular Clusters. II. NGC 1786

NASA Astrophysics Data System (ADS)

Kuehn, Charles A.; Smith, Horace A.; Catelan, Márcio; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

2012-12-01

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series B-V photometric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is seen in most globular clusters. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

1. HISTORIC PHOTOGRAPH, VIEW OF ROUND HILL ROAD BRIDGE, LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. HISTORIC PHOTOGRAPH, VIEW OF ROUND HILL ROAD BRIDGE, LOOKING WEST, CA. 1940. CONNECTICUT DEPARTMENT OF TRANSPORTATION. - Merritt Parkway, Round Hill Road Bridge, Spanning Merritt Parkway at 3.5 mile mark, Greenwich, Fairfield County, CT

Development of a Comprehensive Base-Level Environmental Training Program for Total Environmental Compliance

DTIC Science & Technology

1994-09-01

Business Managers. Ed. Betty Seldner. San Francisco : McGraw Hill, Inc., 1994 11. Gunderson, John. "Federal Facilities Compliance Act," in Environmental...Decision Making for Engineering and Business Managers. Ed. Betty Seldner. San Francisco : McGraw Hill, Inc., 1994 105 12. Heyman, Glenn. "The Role and...San Francisco . McGraw Hill, Inc., 1994 13- Hill, Chuck. Environmental Oversight Branch, Headquarters Air Combat Command. Personal Correspondence

Internal tide generation by abyssal hills using analytical theory

NASA Astrophysics Data System (ADS)

Melet, Angélique; Nikurashin, Maxim; Muller, Caroline; Falahat, S.; Nycander, Jonas; Timko, Patrick G.; Arbic, Brian K.; Goff, John A.

2013-11-01

Internal tide driven mixing plays a key role in sustaining the deep ocean stratification and meridional overturning circulation. Internal tides can be generated by topographic horizontal scales ranging from hundreds of meters to tens of kilometers. State of the art topographic products barely resolve scales smaller than ˜10 km in the deep ocean. On these scales abyssal hills dominate ocean floor roughness. The impact of abyssal hill roughness on internal-tide generation is evaluated in this study. The conversion of M2 barotropic to baroclinic tidal energy is calculated based on linear wave theory both in real and spectral space using the Shuttle Radar Topography Mission SRTM30_PLUS bathymetric product at 1/120° resolution with and without the addition of synthetic abyssal hill roughness. Internal tide generation by abyssal hills integrates to 0.1 TW globally or 0.03 TW when the energy flux is empirically corrected for supercritical slope (i.e., ˜10% of the energy flux due to larger topographic scales resolved in standard products in both cases). The abyssal hill driven energy conversion is dominated by mid-ocean ridges, where abyssal hill roughness is large. Focusing on two regions located over the Mid-Atlantic Ridge and the East Pacific Rise, it is shown that regionally linear theory predicts an increase of the energy flux due to abyssal hills of up to 100% or 60% when an empirical correction for supercritical slopes is attempted. Therefore, abyssal hills, unresolved in state of the art topographic products, can have a strong impact on internal tide generation, especially over mid-ocean ridges.

AmeriFlux US-Blk Black Hills

DOE Data Explorer

Meyers, Tilden [NOAA/ARL

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-Blk Black Hills. Site Description - The Black Hills tower was established by the Institute for Atmospheric Studies of the South Dakota School of Mines and Technology.

Directional topographic site response at Tarzana observed in aftershocks of the 1994 Northridge, California, earthquake: Implications for mainshock motions

USGS Publications Warehouse

Spudich, P.; Hellweg, M.; Lee, W.H.K.

1996-01-01

The Northridge earthquake caused 1.78 g acceleration in the east-west direction at a site in Tarzana, California, located about 6 km south of the mainshock epicenter. The accelerograph was located atop a hill about 15-m high, 500-m long, and 130-m wide, striking about N78??E. During the aftershock sequence, a temporary array of 21 three-component geophones was deployed in six radial lines centered on the accelerograph, with an average sensor spacing of 35 m. Station COO was located about 2 m from the accelerograph. We inverted aftershock spectra to obtain average relative site response at each station as a function of direction of ground motion. We identified a 3.2-Hz resonance that is a transverse oscillation of the hill (a directional topographic effect). The top/base amplification ratio at 3.2 Hz is about 4.5 for horizontal ground motions oriented approximately perpendicular to the long axis of the hill and about 2 for motions parallel to the hill. This resonance is seen most strongly within 50 m of COO. Other resonant frequencies were also observed. A strong lateral variation in attenuation, probably associated with a fault, caused substantially lower motion at frequencies above 6 Hz at the east end of the hill. There may be some additional scattered waves associated with the fault zone and seen at both the base and top of the hill, causing particle motions (not spectral ratios) at the top of the hill to be rotated about 20?? away from the direction transverse to the hill. The resonant frequency, but not the amplitude, of our observed topographic resonance agrees well with theory, even for such a low hill. Comparisons of our observations with theoretical results indicate that the 3D shape of the hill and its internal structure are important factors affecting its response. The strong transverse resonance of the hill does not account for the large east-west mainshock motions. Assuming linear soil response, mainshock east-west motions at the Tarzana accelerograph were amplified by a factor of about 2 or less compared with sites at the base of the hill. Probable variations in surficial shear-wave velocity do not account for the observed differences among mainshock acceleration observed at Tarzana and at two different sites within 2 km of Tarzana.

After runaway: The trans-Hill stage of planetesimal growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lithwick, Yoram

2014-01-01

When planetesimals begin to grow by coagulation, they first enter an epoch of runaway, during which the biggest bodies grow faster than all the others. The questions of how runaway ends and what comes next have not been answered satisfactorily. We show that runaway is followed by a new stage—the 'trans-Hill stage'—that commences when the bodies that dominate viscous stirring ('big bodies') become trans-Hill, i.e., when their Hill velocity matches the random speed of the small bodies they accrete. Subsequently, the small bodies' random speed grows in lockstep with the big bodies' sizes, such that the system remains in themore » trans-Hill state. Trans-Hill growth is crucial for determining the efficiency of growing big bodies, as well as their growth timescale and size spectrum. Trans-Hill growth has two sub-stages. In the earlier one, which occurs while the stirring bodies remain sufficiently small, the evolution is collisionless, i.e., collisional cooling among all bodies is irrelevant. The efficiency of forming big bodies in this collisionless sub-stage is very low, ∼10α << 1, where α ∼ 0.005(a/AU){sup –1} is the ratio between the physical size of a body and its Hill radius. Furthermore, the size spectrum is flat (equal mass per size decade, i.e., q = 4). This collisionless trans-Hill solution explains results from previous coagulation simulations for both the Kuiper Belt and the asteroid belt. The second trans-Hill sub-stage commences once the stirring bodies grow big enough (>α{sup –1} × the size of the accreted small bodies). After that time, collisional cooling among small bodies controls the evolution. The efficiency of forming big bodies rises and the size spectrum becomes more top heavy. Trans-Hill growth can terminate in one of two ways, depending on the sizes of the small bodies. First, mutual accretion of big bodies can become significant and conglomeration proceeds until half of the total mass is converted into big bodies. This mode of growth may explain the observed size distributions of small bodies in the solar system and is explored in our subsequent work. Second, if the big bodies' orbits become separated by their Hill radius, oligarchy commences. This mode likely precedes the formation of fully fledged planets.« less

Mass, charge, and energy separation by selective acceleration with a traveling potential hill

NASA Astrophysics Data System (ADS)

Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

1996-10-01

A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to have broad applications. The primary application is for the enrichment of stable isotopes for medical and industrial tracers. Other applications include mass analysis of unknown gases (atomic and molecular) and metals, extracting single charge states from a multiply charged beam, accelerating the high energy tail in a beam or plasma with a velocity distribution, and beam bunching.

Antigravity hills are visual illusions.

PubMed

Bressan, Paola; Garlaschelli, Luigi; Barracano, Monica

2003-09-01

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.

Scotland

NASA Image and Video Library

2017-12-08

In late February, 2013 the Aqua satellite passed over Scotland as the clouds parted, allowing the Moderate Resolution Imaging Spectroradiometer (MODIS) flying aboard to capture a clear image of the late winter landscape. This image was captured at 1320 UTC (1:20 in the afternoon local time) on February 27. England makes up about the southern third of the image. The border between England and Scotland runs from the River Tweed on the east coast and the Solway Firth along the Cheviot Hills of the west coast. The Solway Firth is an estuary of the Irish Sea, and was filled with tan-colored sediment at the time of this image. Further north on the west coast of Scotland, the Firth of Clyde is hidden under a bank of low clouds (fog). Scotland’s Southern Uplands lie just north of the border and the Central Lowlands just north of that. The Grampian Mountains are found in the center of the country, and the high peaks wear a covering of snow and ice year-round. Finally the Northern Highlands can be seen peeking out from under a large bank of clouds. The Northern Highlands and the Grampian Mountains are separated by a striking feature - the Great Glen Fault. This is a 100 km-long strike-slip fault which runs from Moray Firth in the east to Fort William at the head of Loch Linnhe in the west. The Great Glen contains the United Kingdom’s deepest freshwater loch, the famous Loch Ness. Credit: NASA/GSFC/Jeff Schmaltz/MODIS Land Rapid Response Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

High Speed Video Observations of Natural Lightning and Their Implications to Fractal Description of Lightning

NASA Astrophysics Data System (ADS)

Liu, N.; Tilles, J.; Boggs, L.; Bozarth, A.; Rassoul, H.; Riousset, J. A.

2016-12-01

Recent high speed video observations of triggered and natural lightning flashes have significantly advanced our understanding of lightning initiation and propagation. For example, they have helped resolve the initiation of lightning leaders [Stolzenburg et al., JGR, 119, 12198, 2014; Montanyà et al, Sci. Rep., 5, 15180, 2015], the stepping of negative leaders [Hill et al., JGR, 116, D16117, 2011], the structure of streamer zone around the leader [Gamerota et al., GRL, 42, 1977, 2015], and transient rebrightening processes occurring during the leader propagation [Stolzenburg et al., JGR, 120, 3408, 2015]. We started an observational campaign in the summer of 2016 to study lightning by using a Phantom high-speed camera on the campus of Florida Institute of Technology, Melbourne, FL. A few interesting natural cloud-to-ground and intracloud lightning discharges have been recorded, including a couple of 8-9 stroke flashes, high peak current flashes, and upward propagating return stroke waves from ground to cloud. The videos show that the propagation of the downward leaders of cloud-to-ground lightning discharges is very complex, particularly for the high-peak current flashes. They tend to develop as multiple branches, and each of them splits repeatedly. For some cases, the propagation characteristics of the leader, such as speed, are subject to sudden changes. In this talk, we present several selected cases to show the complexity of the leader propagation. One of the effective approaches to characterize the structure and propagation of lightning leaders is the fractal description [Mansell et al., JGR, 107, 4075, 2002; Riousset et al., JGR, 112, D15203, 2007; Riousset et al., JGR, 115, A00E10, 2010]. We also present a detailed analysis of the high-speed images of our observations and formulate useful constraints to the fractal description. Finally, we compare the obtained results with fractal simulations conducted by using the model reported in [Riousset et al., 2007, 2010].

Global Particle Size Distributions: Measurements during the Atmospheric Tomography (ATom) Project

NASA Astrophysics Data System (ADS)

Brock, C. A.; Williamson, C.; Kupc, A.; Froyd, K. D.; Richardson, M.; Weinzierl, B.; Dollner, M.; Schuh, H.; Erdesz, F.

2016-12-01

The Atmospheric Tomography (ATom) project is a three-year NASA-sponsored program to map the spatial and temporal distribution of greenhouse gases, reactive species, and aerosol particles from the Arctic to the Antarctic. In situ measurements are being made on the NASA DC-8 research aircraft, which will make four global circumnavigations of the Earth over the mid-Pacific and mid-Atlantic Oceans while continuously profiling between 0.2 and 13 km altitude. In situ microphysical measurements will provide an unique and unprecedented dataset of aerosol particle size distributions between 0.004 and 50 µm diameter. This unbiased, representative dataset allows investigation of new particle formation in the remote troposphere, placing strong observational constraints on the chemical and physical mechanisms that govern particle formation and growth to cloud-active sizes. Particles from 0.004 to 0.055 µm are measured with 10 condensation particle counters. Particles with diameters from 0.06 to 1.0 µm are measured with one-second resolution using two ultra-high sensitivity aerosol size spectrometers (UHSASes). A laser aerosol spectrometer (LAS) measures particle size distributions between 0.12 and 10 µm in diameter. Finally, a cloud, aerosol and precipitation spectrometer (CAPS) underwing optical spectrometer probe sizes ambient particles with diameters from 0.5 to 50 µm and images and sizes precipitation-sized particles. Additional particle instruments on the payload include a high-resolution time-of-flight aerosol mass spectrometer and a single particle laser-ablation aerosol mass spectrometer. The instruments are calibrated in the laboratory and on the aircraft. Calibrations are checked in flight by introducing four sizes of polystyrene latex (PSL) microspheres into the sampling inlet. The CAPS probe is calibrated using PSL and glass microspheres that are aspirated into the sample volume. Comparisons between the instruments and checks with the calibration aerosol indicate flight performance within uncertainties expected from laboratory calibrations. Analysis of data from the first ATom circuit in August 2016 shows high concentrations of newly formed particles in the tropical middle and upper troposphere and Arctic lower troposphere.

Interpretation of shallow electrical features from electromagnetic and magnetotelluric surveys at Mount Hood, Oregon

NASA Astrophysics Data System (ADS)

Goldstein, N. E.; Mozley, E.; Wilt, M.

1982-04-01

A magnetotelluric survey, with a reference magnetometer for noise cancellation, was conducted at accessible locations around Mount Hood, Oregon. Thirty-eight tensor magnetotelluric (MT) and remote telluric stations were set up in clusters around the volcano except for the northwest quadrant, a wilderness area. Because of limited access, station locations were restricted to elevations below 1829 m, or no closer than 5 km from the 3424-m summit. On the basis of the MT results, three areas were later investigated in more detail using a large-moment, controlled-source electromagnetic (EM) system developed at Lawrence Berkeley Laboratory and the University of California at Berkeley. One-dimensional interpretations of EM and MT data on the northeast flank of the mountain near the Cloud Cap eruptive center and on the south flank near Timberline Lodge show a similar subsurface resistivity pattern: a resistive surface layer 400-700 m thick, underlain by a conductive layer with variable thickness and resistivity of <20 ohm m. It is speculated that the surface layer consists of volcanics partially saturated with cold meteoric water. The underlying conductive zone is presumed to be volcanics saturated with water heated within the region of the central conduit and, possibly, at the Cloud Cap side vent. This hypothesis is supported by the existence of warm springs at the base of the mountain, most notably Swim Warm Springs on the south flank, and by several geothermal test wells, one of which penetrates the conductor south of Timberline Lodge. The MT data typically gave a shallower depth to the conductive zone than did the EM data. This is attributed, in part, to the error inherent in one-dimensional MT interpretations of geologically or topographically complex areas. On the other hand, MT was better for resolving the thickness of the conductive layer and deeper structure. The MT data show evidence for a moderately conductive north-south structure on the south flank below the Timberline Lodge and for a broad zone of late Tertiary intrusives concealed on the southeast flank.

INTERPRETATION OF SHALLOW ELECTRICAL FEATURES FROM ELECTROMAGNETIC AND MAGNETOTELLURIC SURVEYS AT MOUNT HOOD, OREGON

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilt, M.; Goldstein, N.E.; Mozley, E.

1981-04-01

A magnetotelluric survey, with a reference magnetometer for noise cancellation, was conducted at accessible locations around Mount Hood, Oregon. Thirty-eight tensor magnetotelluric (MT) and remote telluric stations were set up in clusters around the volcano except for the northwest quadrant, a wilderness area. Because of limited access, station locations were restricted to elevations below 1829 m, or no closer than 5 km from the 3424-m summit. On the basis of the MT results, three areas were later investigated in more detail using a large-moment, controlled-source electromagnetic (EM) system developed at Lawrence Berkeley Laboratory and the University of California at Berkeley.more » One-dimensional interpretations of EM and MT data on the northeast flank of the mountain near the Cloud Cap eruptive center and on the south flank near Timberline Lodge show a similar subsurface resistivity pattern: a resistive surface layer 400-700 m thick, underlain by a conductive layer with variable thickness and resistivity of <20 ohm m. It is speculated that the surface layer consists of volcanics partially saturated with cold meteoric water. The underlying conductive zone is presumed to be volcanics saturated with water heated within the region of the central conduit and, possibly, at the Cloud Cap side vent. This hypothesis is supported by the existence of warm springs at the base of the mountain, most notably Swim Warm Springs on the south flank, and by several geothermal test wells, one of which penetrates the conductor south of Timberline Lodge. The MT data typically gave a shallower depth to the conductive zone than did the EM data. This is attributed, in part, to the error inherent in one-dimensional MT interpretations of geologically or topographically complex areas. On the other hand, MT was better for resolving the thickness of the conductive layer and deeper structure. The MT data show evidence for a moderately conductive north-south structure on the south flank below the Timberline Lodge and for a broad zone of late Tertiary intrusives concealed on the southeast flank.« less

ARC-1991-AC91-0610-1

NASA Image and Video Library

1991-10-02

This data was acquired by the NASA C-130B Earth Resources Survey aircraft flying at 6,000 ft. mean sea level at 10:26 a. m. on October 21, 1991. The sensor used was the NS001 Thermatic Mapper Simulator, with a ground resolution of 4.6 meters (15ft). The image area is 4.7 x 3.2 km (2.9 x 2 mi.). The area covered is the Oakland Berkeley Hills near the Caldecott Tunnel (Upper right). Targets over 600 degrees centrigrade are shown as yellow in this composite of three infrared bands (11.6, 2.3, & 1.6 microns). A large condominium complex at the upper right is completely consumed. Areas already burned off sow as pale red. The blue clouds at left are condensed water vapor within the smoke plume, which blocks the infrared wavelength; the smoke itself is transparent. Many hundreds of individual structures can be seen either actively burning or as heat of smouldering debris.

Automated Blazar Light Curves Using Machine Learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Spencer James

Every night in a remote clearing called Fenton Hill high in the Jemez Mountains of central New Mexico, a bank of robotically controlled telescopes tilt their lenses to the sky for another round of observation through digital imaging. Los Alamos National Laboratory’s Thinking Telescopes project is watching for celestial transients including high-power cosmic flashes called, and like all science, it can be messy work. To keep the project clicking along, Los Alamos scientists routinely install equipment upgrades, maintain the site, and refine the sophisticated machinelearning computer programs that process those images and extract useful data from them. Each week themore » system amasses 100,000 digital images of the heavens, some of which are compromised by clouds, wind gusts, focus problems, and so on. For a graduate student at the Lab taking a year’s break between master’s and Ph.D. studies, working with state-of-the-art autonomous telescopes that can make fundamental discoveries feels light years beyond the classroom.« less

Global map of solar power production efficiency, considering micro climate factors

NASA Astrophysics Data System (ADS)

Hassanpour Adeh, E.; Higgins, C. W.

2017-12-01

Natural resources degradation and greenhouse gas emissions are creating a global crisis. Renewable energy is the most reliable option to mitigate this environmental dilemma. Abundancy of solar energy makes it highly attractive source of electricity. The existing global spatial maps of available solar energy are created with various models which consider the irradiation, latitude, cloud cover, elevation, shading and aerosols, and neglect the influence of local meteorological conditions. In this research, the influences of microclimatological variables on solar energy productivity were investigated with an in-field study at the Rabbit Hills solar arrays near Oregon State University. The local studies were extended to a global level, where global maps of solar power were produced, taking the micro climate variables into account. These variables included: temperature, relative humidity, wind speed, wind direction, solar radiation. The energy balance approach was used to synthesize the data and compute the efficiencies. The results confirmed that the solar power efficiency can be directly affected by the air temperature and wind speed.

Investigation of Hill's optical turbulence model by means of direct numerical simulation.

PubMed

Muschinski, Andreas; de Bruyn Kops, Stephen M

2015-12-01

For almost four decades, Hill's "Model 4" [J. Fluid Mech. 88, 541 (1978) has played a central role in research and technology of optical turbulence. Based on Batchelor's generalized Obukhov-Corrsin theory of scalar turbulence, Hill's model predicts the dimensionless function h(κl(0), Pr) that appears in Tatarskii's well-known equation for the 3D refractive-index spectrum in the case of homogeneous and isotropic turbulence, Φn(κ)=0.033C2(n)κ(-11/3) h(κl(0), Pr). Here we investigate Hill's model by comparing numerical solutions of Hill's differential equation with scalar spectra estimated from direct numerical simulation (DNS) output data. Our DNS solves the Navier-Stokes equation for the 3D velocity field and the transport equation for the scalar field on a numerical grid containing 4096(3) grid points. Two independent DNS runs are analyzed: one with the Prandtl number Pr=0.7 and a second run with Pr=1.0 . We find very good agreement between h(κl(0), Pr) estimated from the DNS output data and h(κl(0), Pr) predicted by the Hill model. We find that the height of the Hill bump is 1.79 Pr(1/3), implying that there is no bump if Pr<0.17 . Both the DNS and the Hill model predict that the viscous-diffusive "tail" of h(κl(0), Pr) is exponential, not Gaussian.

Effects of bubbles, cracks, and volcanic tephra on the spectral albedo of bare ice near the Transantarctic Mountains: Implications for sea glaciers on Snowball Earth

NASA Astrophysics Data System (ADS)

Dadic, Ruzica; Mullen, Peter C.; Schneebeli, Martin; Brandt, Richard E.; Warren, Stephen G.

2013-09-01

Spectral albedo was measured along a 6 km transect near the Allan Hills in East Antarctica. The transect traversed the sequence from new snow through old snow, firn, and white ice, to blue ice, showing a systematic progression of decreasing albedo at all wavelengths, as well as decreasing specific surface area (SSA) and increasing density. Broadband albedos under clear-sky range from 0.80 for snow to 0.57 for blue ice, and from 0.87 to 0.65 under cloud. Both air bubbles and cracks scatter sunlight; their contributions to SSA were determined by microcomputed tomography on core samples of the ice. Although albedo is governed primarily by the SSA (and secondarily by the shape) of bubbles or snow grains, albedo also correlates highly with porosity, which, as a proxy variable, would be easier for ice sheet models to predict than bubble sizes. Albedo parameterizations are therefore developed as a function of density for three broad wavelength bands commonly used in general circulation models: visible, near-infrared, and total solar. Relevance to Snowball Earth events derives from the likelihood that sublimation of equatorward-flowing sea glaciers during those events progressively exposed the same sequence of surface materials that we measured at Allan Hills, with our short 6 km transect representing a transect across many degrees of latitude on the Snowball ocean. At the equator of Snowball Earth, climate models predict thick ice, or thin ice, or open water, depending largely on their albedo parameterizations; our measured albedos appear to be within the range that favors ice hundreds of meters thick.

Volcanic Ash -Aircraft Encounter Damages: in Volcanological Point of View

NASA Astrophysics Data System (ADS)

Aydar, Erkan; Aladaǧ, Çaǧdaş Hakan; Menteş, Turhan

2017-04-01

The jet era or age began at 1930 and 40's in aviation sector, with the production of first jet engine for the aircrafts. Since 1950's, the commercial aviation with regular flights were established. Civil aviation and air-transport drastically increased due to intensive demand, and declared at least 10 fold since 1970 by IATA report. Parallelly to technological and economical developpement, the commercial jets became more comfortable, secure and rapid, bringing the world smaller, the countries closer. On the other hand, according to Global Volcanism Program Catalogues of Smithsonian Institute, about 1,500 volcanoes have erupted in the Holocene, 550 of them have had historical eruptions and considered as active. Besides an average of 55-60 volcanoes erupt each year, and about 8-10 of these eruptions produce ash clouds that reach aircraft flight altitudes (Salinas and Watt, 2004). Volcanic ash can be expected to be in air routes at altitudes greater than 9 km (30,000 ft) for roughly 20 days per year worldwide (Miller &Casadeval, 2000). A precious compilation of incidents due to encounters of aircrafts with volcanic ash clouds covering the years between 1953 and 2009 was used in this work (Guffanti et al., 2010-USGS Report) with an additional information on Eyfjallajökull-2010 eruption. According to this compilation,129 incidents happened within the concerned time interval. The damages, in general, fall in second and third class of Severity index, indicating the damages are limited on airframe of the planes, or some abrasions in jet engine, windblast etc.. We focused on fourth class of severity index involving the damages on jet engine of aircraft (engine fail) due to ingestion of volcanic ash and investigate eruption style and caused damage relationships. During the eruptive sequences of Mts Saint Helen (USA), Galunggung (Indonesia, 2 incidents), Redoubt (USA), Pinatubo (Philipinnes), Unzen (Japan), Manam (Papua New Guinea), Soufriere Hills (Lesser Antilles), Chaiten (Chilie), Eyfjallajökull (Iceland). The common point of all those eruptions is that all eruption clouds had the external water input. This input was as phreatomagmatic style eruption, ice plugged-vent clearing-vulcanian, heavy rain fall on eruption cloud or on eruptive vent, typhoon, ice grain in eruptive cloud, etc. We will show water input, case by case, to those eruptions belonging to severity index 4. Besides, we will also present other damages created by volcanic ash-aircraft encounters basing on their eruption styles as a result of advanced statistical methods.

An Investigation of Dust Storms Observed with the Mars Color Imager

NASA Technical Reports Server (NTRS)

Guzewich, Scott D.; Toigo, Anthony D.; Wang, Huiqun

2017-01-01

Daily global imaging by the Mars Color Imager (MARCI) continues the record of the Mars Orbiter Camera (MOC) and has allowed creation of a long-duration record of Martian dust storms. We observe dust storms over the first two Mars years of the MARCI record, including tracking individual storms over multiple sols, as well as tracking the growth and recession of the seasonal polar caps. Using the combined 6 Mars year record of textured dust storms (storms with visible textures on the observed dust cloud tops), we study the relationship between textured dust storm activity and meteorology (as simulated by the MarsWRF general circulation model) and surface properties. We find that textured dust storms preferentially occur in places and seasons with above average surface wind stress. Textured dust storm occurrence also has a modest linear anti-correlation with surface albedo (0.43) and topography (0.40). Lastly, we perform an empirical orthogonal function (EOF) analysis on the distribution of occurrence of textured dust storms and find that over 50 of the variance in textured dust storm activity can be explained by two EOF modes. We associate the first EOF mode with cap-edge storms just before Ls = 180deg and the second EOF mode with flushing dust storms that occur from Ls = 180-210deg and again near Ls = 320deg.

OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF GOLD HILL MILL, ROAD, AND WARM SPRINGS CAMP BUILDINGS, LOOKING SOUTH SOUTHEAST. THE FUNCTION OF THE FLAT AREA AT CENTER RIGHT IS UNKNOWN. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

GHG PSD Permit: Cheyenne Light, Fuel & Power / Black Hills Power, Inc. – Cheyenne Prairie Generating Station

EPA Pesticide Factsheets

This page contains the final PSD permit for the Cheyenne Light, Fuel & Power / Black Hills Power, Inc. Cheyenne Prairie Generating Station, located in Laramie, Wyoming, and operated by Black Hills Service Company.

Synthesis of hemoglobin Gun Hill: increased synthesis of the heme-free βGH globin chain and subunit exchange with a free α-chain pool

PubMed Central

Rieder, Ronald F.

1971-01-01

Hemoglobin Gun Hill is an unstable mutant hemoglobin associated with mild compensated hemolysis. This abnormal protein has a deletion of five amino acids in the β-chains. The deletion includes the heme-binding proximal histidine at position 92. The β-chains of hemoglobin Gun Hill lack heme groups. Approximately 32% of the circulating hemoglobin in heterozygous subjects consists of the mutant hemoglobin. When reticulocytes were incubated with radioactive amino acid the specific activity of hemoglobin Gun Hill was three to six times that of hemoglobin A. Total incorporation of radioactivity into hemoglobin Gun Hill was two to three times that into hemoglobin A. There were 20-50% more total counts in β-Gun Hill (βGH) than in βA. These results indicate that in reticulocytes there was greater synthesis of the abnormal β-chains than βA-chains. The ratio of the specific activities of the α-chains of hemoglobin Gun Hill to the α-chains of hemoglobin A was 20: 1. There was evidence of a free pool of α-chains in the reticulocytes containing hemoglobin Gun Hill. After 10 min of incubation approximately 40% of the total α-chain radioactivity was in the free pool. When protein synthesis was blocked by incubation of reticulocytes with puromycin, the specific activity of the α-chains of hemoglobin Gun Hill continued to increase due to direct exchange of α-subunits between the free pool and preformed hemoglobin Gun Hill. Studies of the assembly of βA and βGH revealed that the rates of translation of the two polypeptide chains were equal and uniform. No evidence was obtained for the existence of “slow points” in the process of globin chain assembly. The studies also suggest that lack of strong heme-globin binding does not hinder the synthesis of globin chains. PMID:5540175

A coevolutionary arms race causes ecological speciation in crossbills.

PubMed

Smith, Julie W; Benkman, Craig W

2007-04-01

We examined three ecological factors potentially causing premating reproductive isolation to determine whether divergent selection as a result of coevolution between South Hills crossbills (Loxia curvirostra complex) and Rocky Mountain lodgepole pine (Pinus contorta latifolia) promotes ecological speciation. One factor was habitat isolation arising because of enhanced seed defenses of lodgepole pine in the South Hills. This caused the crossbill call types (morphologically and vocally differentiated forms) adapted to alternative resources to be rare. Another occurred when crossbills of other call types moved into the South Hills late in the breeding season and feeding conditions were deteriorating so that relatively few non-South Hills crossbills bred ("immigrant infecundity"). Finally, among those crossbills that bred, pairing was strongly assortative by call type (behavioral isolation). Total reproductive isolation between South Hills crossbills and the two other crossbills most common in the South Hills (call types 2 and 5) summed to .9975 and .9998, respectively, on a scale of 0 (no reproductive isolation) to 1 (complete reproductive isolation). These extremely high levels of reproductive isolation indicate that the divergent selection resulting from the coevolutionary arms race between crossbills and lodgepole pine is causing the South Hills crossbill to speciate.

Experimental investigation of flow over two-dimensional multiple hill models.

PubMed

Li, Qing'an; Maeda, Takao; Kamada, Yasunari; Yamada, Keisuke

2017-12-31

The aim of this study is to investigate the flow field characteristics in ABL (Atmospheric Boundary Layer) flow over multiple hills and valleys in two-dimensional models under neutral conditions. Active turbulence grids and boundary layer generation frame were used to simulate the natural winds in wind tunnel experiments. As a result, the mean wind velocity, the velocity vector diagram and turbulence intensity around the hills were investigated by using a PIV (Particle Image Velocimetry) system. From the measurement results, it was known that the average velocity was increased along the upstream slope of upside hill, and then separated at the top of the hills, the acceleration region of U/U ref >1 was generated at the downstream of the hill. Meanwhile, a large clockwise circulation flow was generated between the two hill models. Moreover, the turbulence intensity showed small value in the circulation flow regions. Compared to 1H model, the turbulence intensity in the mainstream direction showed larger value than that in the vertical direction. This paper provided a better understanding of the wind energy distribution on the terrain for proper selection of suitable sites for installing wind farms in the ABL. Copyright © 2017 Elsevier B.V. All rights reserved.

Temperature dependent kinetic measurements of isoprene oxidation products exposed to OH, NO3 and SO4- in aqueous solution.

NASA Astrophysics Data System (ADS)

Schöne, L.; Hoffmann, D.; Herrmann, H.

2010-07-01

The troposphere contains a complex mixture of numerous gases, liquid water and diverse solid particles which undergo intricate processes. Volatile organic compound (VOC) emissions from anthropogenic and biogenic sources are very important for the tropospheric chemistry and other processes such as secondary organic particle mass formation. Emissions of biogenic volatile organic compounds (BVOCs) exceed those VOCs coming from human activity by a factor of 10 [1]. Isoprene (2-methyl-1,3-butadiene, C5H8) emissions represent approximately 40% of the emitted BVOCs, leading to an estimated source strength of 500-750Tgyr-1 [2]. As isoprene has a small Henry coefficient, its oxidation occurs solely in the gas phase. The formed first oxidation products methacrolein (MACR), methyl vinyl ketone (MVK), methacrylic acid (MAA) and acrylic acid (ACA) are therefore firstly located in that phase. Even if the Henry coefficients of the main isoprene oxidation products MACR and MVK are already higher than those of isoprene partitioning of theses compounds into the aqueous phase of rain, fog and cloud droplets and particles was neglected. Correspondingly, aqueous phase oxidation processes of MACR and MVK were sparsely investigated in the past. A recent study [3], however, reports much higher aqueous phase concentrations of MACR and MVK than expected from their Henry coefficients. To evaluate the importance of liquid phase reactions of early isoprene oxidation products for the organic particle mass production, kinetic studies are necessary. Therefore, this work investigated the temperature dependence of methacrolein, methyl vinyl ketone, methacrylic acid and acrylic acid exposed to NO3, SO4- and OH radicals in the range of 278K to 318K in the aqueous phase. Furthermore, the effect of the acid-base equilibrium on the reactivity of the two acids was studied by measuring the kinetics of the dissociated and undissociated acids. The measurements were performed using a laser-photolysis laser long path absorption (LP-LLPA) technique. The measurements’ analysis confirmed in all cases the much higher reactivity of the hydroxyl radical (k~10^9M-1s-1) in comparison to the sulfate (k~108 M-1s-1) and the nitrate (k~10^7M-1s-1) radical, with methacrylic acid showing steadily the highest reactivity among the investigated substances. The temperature dependence of the measured rate constants is most distinct for nitrate radical reactions and weakest for those with sulfate radicals. Referred to the two different considered pH-values of the acids, the protonated form reacts slightly faster than the unprotonated form and shows a less distinct temperature dependence. [1] Guenther et al., 1995: Global-model of natural volatile organic-compound emissions. Journal of Geophysical Research - Atmosphere, 100(D5), 8873-8892. [2] Guenther et al. 2006: Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature). Atmospheric Chemical Physics, 6, 3181-3210. [3] van Pinxteren et al., 2005: Schmücke hill cap cloud and valley stations aerosol chemical composition during FEBUKO (II): Organic compounds. Atmospheric Environment, 39, 4305-4320.

VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW TO SOUTHEAST TOWARD QUARTERMASTER BUILDINGS GROUP AND RESERVOIR HILL, FROM AMMUNITION (IGLOO) HILL. (Part 2 of a 3 view panorama; see also CA-2398-J-1 and CA-2398-16.) - Hamilton Field, East of Nave Drive, Novato, Marin County, CA

Black Hills Region, SD, USA

NASA Image and Video Library

1973-06-22

SL2-81-157 (22 June 1973) --- This view of the Black Hills Region, SD (44.0N, 104.0W) shows the scenic Black Hills where Mt. Rushmore and other monuments are located. Cities and towns in this view include: Rapid City, Deadwood, and Belle Fourche with the nearby Belle Fourche Reservoir. Notable in this scene are the recovering burn scars (seen as irregular shaped light toned patches) from a 1959 forest fire in the Black Hills National Forest near the edge of the photo. Photo credit: NASA

Setup and first airborne application of an aerosol optical properties package for the In-service Aircraft Global Observing System IAGOS.

NASA Astrophysics Data System (ADS)

Bundke, Ulrich; Freedman, Andrew; Herber, Andreas; Mattis, Ina; Berg, Marcel; De Faira, Julia; Petzold, Andreas

2016-04-01

The atmospheric aerosol influences the climate twofold via the direct interaction with solar radiation and indirectly effecting microphysical properties of clouds. The latter has the largest uncertainty according to the last IPPC Report. A measured in situ climatology of the aerosol microphysical and optical properties is needed to reduce the reported uncertainty of the aerosol climate impact. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) responds to the increasing requests for long-term, routine in situ observational data by using commercial passenger aircraft as measurement platform. However, scientific instrumentation for the measurement of atmospheric constituents requires major modifications before being deployable aboard in-service passenger aircraft. The prototype of the IAGOS Aerosol Package (IAGOS-P2E) consists of two modified CAPS (Cavity Attenuated Phase Shift) instruments from Aerodyne Research, Inc. and one optical particle counter (Model Grimm Sky OPC 1.129). The CAPS PMex monitor provides a measurement of the optical extinction (the sum of scattering and absorption) of an ambient sample of particles. There is a choice of 5 different wavelengths - blue (450 nm), green (530 nm), red (630 nm), far red (660 nm) and near infrared (780 nm) - which match the spectral bands of most other particle optical properties measurement equipment. In our prototype setup we used the instrument operating at 630nm wavelength (red). The second CAPS instrument we have chosen is the CAPS NO2 monitor. This instrument provides a direct absorption measurement of nitrogen dioxide in the blue region of the electromagnetic spectrum (450 nm). Unlike standard chemiluminescence-based monitors, the instrument requires no conversion of NO2 to another species and thus is not sensitive to other nitro-containing species. In the final IAGOS Setup, up to 4 CAPS might be used to get additional aerosol properties using the different spectral information. The number of CAPS units to be used will depend on the size of the final electronic boards which are currently under development. The Sky OPC measures the size distribution theoretically up to 32 μm covering the relevant size information for calculation of aerosol optical properties. Because of the inlet cut off diameter of D50 = 3μm we are using the 16 channel mode in the range of 250 nm - 2.5 μm at 1 Hz resolution. In this presentation the setup of the IAGOS Aerosol package P2E is presented and characterized for pressure levels relevant for the planned application, down to cruising level of 150 hPa. In our aerosol lab we have tested the system against standard instrumentation with different aerosol test substances. In addition first results for airborne measurements are shown from a first airborne field campaign where in situ profiles are compared to LIDAR measurements over Bornholm (Denmark) and Lindenberg (Germany).

Biogeography of the Shimba Hills ecosystem herpetofauna in Kenya

PubMed Central

Malonza, Patrick K.; Mulwa, David M.; Nyamache, Joash O.; Jones, Georgina

2018-01-01

The Shimba Hills ecosystem along the south coast of Kenya is a key East African biodiversity hotspot. Historically, it is biogeographically assignable to the East African coastal biome. We examined the current Shimba Hills herpetofauna and their zoogeographical affinities to the coastal forests and nearby Eastern Arc Mountains biodiversity hotspots. The key studied sites included the Shimba Hills National Reserve, forest reserves, Kaya forests, and adjacent private land. Data on herpetofaunal richness were obtained from recent field surveys, literature, and specimens held at the National Museums of Kenya, Herpetology Section Collection, Nairobi. The Makadara, Mwele, and Longo-Mwagandi forests within the Shimba Hills National Reserve hosted the highest number of unique and rare species. Generally, the forest reserves and Kaya forests were important refuges for forest-associated species. On private land, Mukurumudzi Dam riparian areas were the best amphibian habitat and were host to three IUCN (Red List) Endangered-EN amphibian species, namely, Boulengerula changamwensis, Hyperolius rubrovermiculatus, and Afrixalus sylvaticus, as well as one snake species Elapsoidea nigra. Using herpetofauna as zoogeographic indicators, the Shimba Hills were determined to be at a crossroads between the coastal forests (13 endemic species) and the Eastern Arc Mountains (seven endemic species). Most of the Eastern Arc Mountains endemic species were from recent records, and thus more are likely to be found in the future. This ‘hybrid’ species richness pattern is attributable to the hilly topography of the Shimba Hills and their proximity to the Indian Ocean. This has contributed to the Shimba Hills being the richest herpetofauna area in Kenya, with a total of 89 and 38 reptile and amphibian species, respectively. Because of its unique zoogeography, the Shimba Hills ecosystem is undoubtedly a key biodiversity area for conservation investment. PMID:29515091

Biogeography of the Shimba Hills ecosystem herpetofauna in Kenya.

PubMed

Malonza, Patrick K; Mulwa, David M; Nyamache, Joash O; Jones, Georgina

2018-03-18

The Shimba Hills ecosystem along the south coast of Kenya is a key East African biodiversity hotspot. Historically, it is biogeographically assignable to the East African coastal biome. We examined the current Shimba Hills herpetofauna and their zoogeographical affinities to the coastal forests and nearby Eastern Arc Mountains biodiversity hotspots. The key studied sites included the Shimba Hills National Reserve, forest reserves, Kaya forests, and adjacent private land. Data on herpetofaunal richness were obtained from recent field surveys, literature, and specimens held at the National Museums of Kenya, Herpetology Section Collection, Nairobi. The Makadara, Mwele, and Longo-Mwagandi forests within the Shimba Hills National Reserve hosted the highest number of unique and rare species. Generally, the forest reserves and Kaya forests were important refuges for forest-associated species. On private land, Mukurumudzi Dam riparian areas were the best amphibian habitat and were host to three IUCN (Red List) Endangered-EN amphibian species, namely, Boulengerula changamwensis, Hyperolius rubrovermiculatus, and Afrixalus sylvaticus, as well as one snake species Elapsoidea nigra. Using herpetofauna as zoogeographic indicators, the Shimba Hills were determined to be at a crossroads between the coastal forests (13 endemic species) and the Eastern Arc Mountains (seven endemic species). Most of the Eastern Arc Mountains endemic species were from recent records, and thus more are likely to be found in the future. This 'hybrid' species richness pattern is attributable to the hilly topography of the Shimba Hills and their proximity to the Indian Ocean. This has contributed to the Shimba Hills being the richest herpetofauna area in Kenya, with a total of 89 and 36 reptile and amphibian species, respectively. Because of its unique zoogeography, the Shimba Hills ecosystem is undoubtedly a key biodiversity area for conservation investment.

A cylindrical quadrupole ion trap in combination with an electrospray ion source for gas-phase luminescence and absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stockett, Mark H., E-mail: stockett@phys.au.dk; Houmøller, Jørgen; Støchkel, Kristian

2016-05-15

A relatively simple setup for collection and detection of light emitted from isolated photo-excited molecular ions has been constructed. It benefits from a high collection efficiency of photons, which is accomplished by using a cylindrical ion trap where one end-cap electrode is a mesh grid combined with an aspheric condenser lens. The geometry permits nearly 10% of the emitted light to be collected and, after transmission losses, approximately 5% to be delivered to the entrance of a grating spectrometer equipped with a detector array. The high collection efficiency enables the use of pulsed tunable lasers with low repetition rates (e.g.,more » 20 Hz) instead of continuous wave (cw) lasers or very high repetition rate (e.g., MHz) lasers that are typically used as light sources for gas-phase fluorescence experiments on molecular ions. A hole has been drilled in the cylinder electrode so that a light pulse can interact with the ion cloud in the center of the trap. Simulations indicate that these modifications to the trap do not significantly affect the storage capability and the overall shape of the ion cloud. The overlap between the ion cloud and the laser light is basically 100%, and experimentally >50% of negatively charged chromophore ions are routinely photodepleted. The performance of the setup is illustrated based on fluorescence spectra of several laser dyes, and the quality of these spectra is comparable to those reported by other groups. Finally, by replacing the optical system with a channeltron detector, we demonstrate that the setup can also be used for gas-phase action spectroscopy where either depletion or fragmentation is monitored to provide an indirect measurement on the absorption spectrum of the ion.« less

High Ice Water Concentrations in the 19 August 2015 Coastal Mesoconvective System

NASA Technical Reports Server (NTRS)

Proctor, Fred H.; Harrah, Steven; Switzer, George F.; Strickland, Justin K.; Hunt, Patricia J.

2017-01-01

During August 2015, NASA's DC-8 research aircraft was flown into High Ice Water Content (HIWC) events as part of a three-week campaign to collect airborne radar data and to obtain measurements from microphysical probes. Goals for this flight campaign included improved characterization of HIWC events, especially from an airborne radar perspective. This paper focuses on one of the flight days, in which a coastal mesoscale convective system (MCS) was investigated for HIWC conditions. The system appears to have been maintained by bands of convection flowing in from the Gulf of Mexico. These convective bands were capped by a large cloud canopy, which masks the underlying structure if viewed from an infrared sensing satellite. The DC-8 was equipped with an IsoKinetic Probe that measured ice concentrations of up to 2.3 g m(exp -3) within the cloud canopy of this system. Sustained measurements of ice crystals with concentrations exceeding 1 g m(exp -3) were encountered for up to ten minutes of flight time. Airborne Radar reflectivity factors were found to be weak within these regions of high ice water concentrations, suggesting that Radar detection of HIWC would be a challenging endeavor. This case is then investigated using a three-dimensional numerical cloud model. Profiles of ice water concentrations and radar reflectivity factor demonstrate similar magnitudes and scales between the flight measurements and model simulation. Also discussed are recent modifications to the numerical model's ice-microphysics that are based on measurements during the flight campaign. The numerical model and its updated ice-microphysics are further validated with a simulation of a well-known case of a supercell hailstorm measured during the Cooperative Convective Precipitation Experiment. Differences in HIWC between the continental supercell and the coastal MCS are discussed.

A cylindrical quadrupole ion trap in combination with an electrospray ion source for gas-phase luminescence and absorption spectroscopy.

PubMed

Stockett, Mark H; Houmøller, Jørgen; Støchkel, Kristian; Svendsen, Annette; Brøndsted Nielsen, Steen

2016-05-01

A relatively simple setup for collection and detection of light emitted from isolated photo-excited molecular ions has been constructed. It benefits from a high collection efficiency of photons, which is accomplished by using a cylindrical ion trap where one end-cap electrode is a mesh grid combined with an aspheric condenser lens. The geometry permits nearly 10% of the emitted light to be collected and, after transmission losses, approximately 5% to be delivered to the entrance of a grating spectrometer equipped with a detector array. The high collection efficiency enables the use of pulsed tunable lasers with low repetition rates (e.g., 20 Hz) instead of continuous wave (cw) lasers or very high repetition rate (e.g., MHz) lasers that are typically used as light sources for gas-phase fluorescence experiments on molecular ions. A hole has been drilled in the cylinder electrode so that a light pulse can interact with the ion cloud in the center of the trap. Simulations indicate that these modifications to the trap do not significantly affect the storage capability and the overall shape of the ion cloud. The overlap between the ion cloud and the laser light is basically 100%, and experimentally >50% of negatively charged chromophore ions are routinely photodepleted. The performance of the setup is illustrated based on fluorescence spectra of several laser dyes, and the quality of these spectra is comparable to those reported by other groups. Finally, by replacing the optical system with a channeltron detector, we demonstrate that the setup can also be used for gas-phase action spectroscopy where either depletion or fragmentation is monitored to provide an indirect measurement on the absorption spectrum of the ion.

The solsticial pause on Mars: 2 modelling and investigation of causes

NASA Astrophysics Data System (ADS)

Mulholland, David P.; Lewis, Stephen R.; Read, Peter L.; Madeleine, Jean-Baptiste; Forget, Francois

2016-01-01

The martian solsticial pause, presented in a companion paper (Lewis et al., 2016), was investigated further through a series of model runs using the UK version of the LMD/UK Mars Global Climate Model. It was found that the pause could not be adequately reproduced if radiatively active water ice clouds were omitted from the model. When clouds were used, along with a realistic time-dependent dust opacity distribution, a substantial minimum in near-surface transient eddy activity formed around solstice in both hemispheres. The net effect of the clouds in the model is, by altering the thermal structure of the atmosphere, to decrease the vertical shear of the westerly jet near the surface around solstice, and thus reduce baroclinic growth rates. A similar effect was seen under conditions of large dust loading, implying that northern midlatitude eddy activity will tend to become suppressed after a period of intense flushing storm formation around the northern cap edge. Suppression of baroclinic eddy generation by the barotropic component of the flow and via diabatic eddy dissipation were also investigated as possible mechanisms leading to the formation of the solsticial pause but were found not to make major contributions. Zonal variations in topography were found to be important, as their presence results in weakened transient eddies around winter solstice in both hemispheres, through modification of the near-surface flow. The zonal topographic asymmetry appears to be the primary reason for the weakness of eddy activity in the southern hemisphere relative to the northern hemisphere, and the ultimate cause of the solsticial pause in both hemispheres. The meridional topographic gradient was found to exert a much weaker influence on near-surface transient eddies.

77 FR 67640 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-13

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Combined Notice of Filings 1 Take notice.... Applicants: Canadian Hills Wind, LLC, Canadian Hills Holdings Company, LLC. Description: Application for... Expedited Consideration and Confidential Treatment of Canadian Hills Wind, LLC, et al. Filed Date: 11/2/12...

Long-Term Monitoring Network Optimization Evaluation for Operable Unit 2, Bunker Hill Mining and Metallurgical Complex Superfund Site, Idaho

EPA Pesticide Factsheets

This report presents a description and evaluation of the ground water and surface water monitoring program associated with the Bunker Hill Mining and Metallurgical Complex Superfund Site (Bunker Hill) Operable Unit (OU) 2.

Surface faulting along the Superstition Hills fault zone and nearby faults associated with the earthquakes of 24 November 1987

USGS Publications Warehouse

Sharp, R.V.

1989-01-01

The M6.2 Elmore Desert Ranch earthquake of 24 November 1987 was associated spatially and probably temporally with left-lateral surface rupture on many northeast-trending faults in and near the Superstition Hills in western Imperial Valley. Three curving discontinuous principal zones of rupture among these breaks extended northeastward from near the Superstition Hills fault zone as far as 9km; the maximum observed surface slip, 12.5cm, was on the northern of the three, the Elmore Ranch fault, at a point near the epicenter. Twelve hours after the Elmore Ranch earthquake, the M6.6 Superstition Hills earthquake occurred near the northwest end of the right-lateral Superstition Hills fault zone. We measured displacements over 339 days at as many as 296 sites along the Superstition Hills fault zone, and repeated measurements at 49 sites provided sufficient data to fit with a simple power law. The overall distributions of right-lateral displacement at 1 day and the estimated final slip are nearly symmetrical about the midpoint of the surface rupture. The average estimated final right-lateral slip for the Superstition Hills fault zone is ~54cm. The average left-lateral slip for the conjugate faults trending northeastward is ~23cm. The southernmost ruptured member of the Superstition Hills fault zone, newly named the Wienert fault, extends the known length of the zone by about 4km. -from Authors

The parameterization of the planetary boundary layer in the UCLA general circulation model - Formulation and results

NASA Technical Reports Server (NTRS)

Suarez, M. J.; Arakawa, A.; Randall, D. A.

1983-01-01

A planetary boundary layer (PBL) parameterization for general circulation models (GCMs) is presented. It uses a mixed-layer approach in which the PBL is assumed to be capped by discontinuities in the mean vertical profiles. Both clear and cloud-topped boundary layers are parameterized. Particular emphasis is placed on the formulation of the coupling between the PBL and both the free atmosphere and cumulus convection. For this purpose a modified sigma-coordinate is introduced in which the PBL top and the lower boundary are both coordinate surfaces. The use of a bulk PBL formulation with this coordinate is extensively discussed. Results are presented from a July simulation produced by the UCLA GCM. PBL-related variables are shown, to illustrate the various regimes the parameterization is capable of simulating.

Early Spring Dust over the Mediterranean Sea

NASA Technical Reports Server (NTRS)

2002-01-01

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) observed this large cloud of dust (brownish pixels) blowing from northern Africa across the Mediterranean Sea on March 4, 2002. The dust can be seen clearly blowing across Southern Italy, Albania, Greece, and Turkey-all along the Mediterranean's northeastern shoreline. Notice that there also appears to be human-made aerosol pollution (greyish pixels) pooling in the air just south of the Italian Alps and blowing southeastward over the Adriatic Sea. The Alps can be easily identified as the crescent-shaped, snow-capped mountain range in the top center of this true-color scene. There also appears to be a similar haze over Austria, Hungary, and Yugoslavia to the north and east of Italy. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Patty Smith Hill, Gifted Early Childhood Educator of the Progressive Era.

ERIC Educational Resources Information Center

Rudnitski, Rose A.

1995-01-01

This article chronicles the development of Patty Smith Hill, eminent educator of the Progressive Era. Hill was largely responsible for adding kindergarten to the elementary school curriculum, was the author of the "Happy Birthday" song, and a member of the Woman's Suffrage Movement. (DB)

Drawing entitled "Planting Plan Pine Hills, Gd. Sta. U.S. Department ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Drawing entitled "Planting Plan Pine Hills, Gd. Sta. U.S. Department of Agriculture, Forest Service, Region 5. L. Glenn Hall, landscape engineer. 11-5-35. - Pine Hills Station, Barracks, West Side of Boulder Creek Road at Engineers Road, Julian, San Diego County, CA

78 FR 34366 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

... Solar, LLC. Description: Application and Initial Baseline Tariff Filing to be effective 8/1/2013. Filed... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Combined Notice of Filings 1 Take notice.... Applicants: Beech Ridge Energy LLC, Bishop Hill Energy LLC, Bishop Hill Energy III LLC, Bishop Hill...

77 FR 6553 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

.... Applicants: American Electric Power Service Corporation, AEP Energy Partners, Inc., CSW Energy Services, Inc., Central and South West Services, Inc. Description: Notice of change in status of American Electric Power.... Applicants: Black Hills/Colorado Electric Utility Co, LP, Black Hills Colorado IPP, LLC, Black Hills Power...

78 FR 65634 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-01

... Updated Market Power Analysis of the Black Hills Corporation Public Utilities for the Northwest Region..., LLC submits the Triennial Market Power Update Analysis for Markets in the Northwest Region pursuant to...: Black Hills Power, Inc., Cheyenne Light Fuel & Power Company, Black Hills/Colorado Electric Utility Co...

3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. BUNKER HILL LEAD SMELTER. VIEW IS FROM CIA TO THE SOUTHWEST. BUILDINGS NOTED IN ID-29-2 APPEAR, IN ADDITION TO DRY ORE PLANT AND BONNOT COAL PULVERIZING EQUIPMENT BUILDING ON THE RIGHT. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

Influence of Solar Wind on the Global Electric Circuit, and Inferred Effects on Cloud Microphysics, Temperature, and Dynamics in the Troposphere

NASA Astrophysics Data System (ADS)

Tinsley, Brian A.

2000-11-01

There are at least three independent ways in which the solar wind modulates the flow of current density (Jz) in the global electric circuit. These are (A) changes in the galactic cosmic ray energy spectrum, (B) changes in the precipitation of relativistic electrons from the magnetosphere, and (C) changes in the ionospheric potential distribution in the polar caps due to magnetosphere-ionosphere coupling. The current density J_z flows between the ionosphere and the surface, and as it passes through conductivity gradients it generates space charge concentrations dependent on J_z and the conductivity gradient. The gradients are large at the surfaces of clouds and space charge concentrations of order 1000 to 10,000 elementary charges per cm^3 can be generated at cloud tops. The charge transfers to droplets, many of which are evaporating at the cloud-clear air interface. The charge remains on the residual evaporation nuclei with a lifetime against leakage of order 1000 sec, and for a longer period the nuclei also retain coatings of sulfate and organic compounds adsorbed by the droplet while in the cloud. The charged evaporation nuclei become well mixed with more droplets in many types of clouds with penetrative mixing. The processes of entrainment and evaporation are also efficient for these clouds. The collection of such nuclei by nearby droplets is greatly increased by the electrical attraction between the charge on the particle and the image charge that it creates on the droplet. This process is called electroscavenging. Because the charge on the evaporation nuclei is derived from the original space charge, it depends on J_z, giving a rate of electroscavenging responsive to the solar wind inputs. There may be a number of ways in which the electroscavenging has consequences for weather and climate. One possibility is enhanced production of ice. The charged evaporation nuclei have been found to be good ice forming nuclei because of their coatings, and so in supercooled clouds droplet freezing can occur by contact ice nucleation, as the evaporation nuclei are electroscavenged. Although quantitative models for the all the cloud microphysical processes that may be involved have not yet been produced, we show that for many clouds, especially those with broad droplet size distributions, relatively high droplet concentrations, and cloud top temperatures just below freezing, this process is likely to dominate over other primary ice nucleation processes. In these cases there are likely to be effects on cloud albedo and rates of sedimentation of ice, and these will depend on J_z. For an increase in ice production in thin clouds such as altocumulus or stratocumulus the main effect is a decrease in albedo to incoming solar radiation, and in opacity to outgoing longwave radiation. At low latitudes the surface and troposphere heat, and at high latitudes in winter they cool. The change in meridional temperature gradient affects the rate of cyclogenesis, and the amplitude of planetary waves. For storm clouds, as in winter cyclones, the effect of increased ice formation is mainly to increase the rate of glaciation of lower level clouds by the seeder-feeder process. The increase in precipitation efficiency increases the rate of transfer of latent heat between the air mass and the surface. In most cyclones this is likely to result in intensification, producing changes in the vorticity area index as observed. Cyclone intensification also increases the amplitude of planetary waves, and shifts storm tracks, as observed. In this paper we first describe the production of space charge and the way in which it may influence the rate of ice nucleation. Then we review theory and observations of the solar wind modulation of J_z, and the correlated changes in atmospheric temperature and dynamics in the troposphere. The correlations are present for each input, (A, B, and C), and the detailed patterns of responses provide support for the inferred electrical effects on the physics of clouds, affecting precipitation, temperature and dynamics.

Analysis of Rapidly Developing Low Cloud Ceilings in a Stable Environment

NASA Technical Reports Server (NTRS)

Wheeler, Mark M.; Case, Jonathan L.

2005-01-01

This report describes the work done by the Applied Meteorology Unit (AMU) in developing a database of days that experienced rapid (< 90 minutes) low cloud formation in a stable atmosphere, resulting in ceilings at the Shuttle Landing Facility (TTS) that violated Space Shuttle Flight Rules (FR). The meteorological conditions favoring the rapid formation of low ceilings include the presence of any inversion below 8000 ft, high relative humidity beneath the inversion, and a clockwise turning of the winds from the surface to the middle troposphere (approx. 15000 ft). The AMU compared and contrasted the atmospheric and thermodynamic conditions between days with rapid low ceiling formation and days with low ceiling resulting from other mechanism. The AMU found that the vertical wind profile is the probable discerning factor between the rapidly-forming ceiling days and other low ceiling days at TTS. Most rapidly-developing low ceiling days had a clockwise turning of the winds with height, whereas other low ceiling days typically had a counter-clockwise turning of the winds with height or negligible vertical wind shear. Forecasters at the Space Meteorology Group (SMG) issue 30 to 90 minute forecasts for low cloud ceilings at TTS to support Space Shuttle landings. Mission verification statistics have shown ceilings to be the number one forecast challenge. More specifically, forecasters at SMG are concerned with any rapidly developing clouds ceilings below 8000 ft in a stable, capped thermodynamic environment, Therefore, the AMU was tasked to examine archived events of rapid stable cloud formation resulting in ceilings below 8000 ft, and document the atmospheric regimes favoring this type of cloud development. The AMU examined the cool season months of November to March during the years of 1993-2003 for days that had low-level inversions and rapid, stable low cloud formation that resulted in ceilings violating the Space Shuttle FR. The AMU wrote and modified existing code to identify inversions from the morning Cape Canaveral, FL rawinsonde (XMR) during the cool season and output pertinent sounding information. They parsed all days with cloud ceilings below 8000 ft at TTS, forming a database of possible rapidly-developing low ceiling events. Days with precipitation or noticeable fog bum-off situations were excluded from the database. Only the daytime hours were examined for possible ceiling development events since low clouds are easier to diagnose with visible satellite imagery. Follow-on work would expand the database to include nighttime cases, using a special enhancement of the infrared imagery for identifying areas of low clouds. The report presents two sample cases of rapidly-developing low cloud ceilings. These cases depict the representative meteorological and thermodynamic characteristics of such events. The cases also illustrate how quickly the cloud decks can develop, sometimes forming in 30 minutes or less. The report also summarizes the composite meteorological conditions for 20 event days with rapid low cloud ceiling formation and 48 non-events days consisting of advection or widespread low cloud ceilings. The meteorological conditions were quite similar for both the event and non-event days, since both types of days experienced low cloud ceilings. Both types of days had a relatively moist environment beneath the inversion based below 8000 ft. In the 20 events identified, de onset of low ceilings occurred between 1200-1800 UTC in every instance. The distinguishing factor between the event and non-event days appears to be the vertical wind profile in the XMR sounding. Eighty-five percent of the event days had a clockwise turning of the winds with height in the lower to middle troposphere whereas 83% of the non-events had a counter-clockwise turning of the winds with height or negligible vertical wind shear. A clockwise turning of the winds with height indicates a warm advection regime, which supports large-scale rising motn and possible cloud formation. Meanwhile, a counter-clockwise turning of the winds with height indicates cold advection or sinking motion in a post-cold frontal environment.

A Fiscal Cliff: The Current U.S. Federal Budget, Potential Cuts, and Impacts on Science Funding

NASA Astrophysics Data System (ADS)

Uhlenbrock, K. M.; Landau, E. A.; Hankin, E. R.

2012-12-01

As lawmakers on Capitol Hill face challenges to reach an agreement on how to cut the deficit while growing the economy, scientists must join the discussion and outline the serious impacts cuts to federal science programs will have on our society. Consistent and sustained federal science funding (discretionary spending) is an ever increasing struggle with the rising costs of mandatory spending and decrease in revenues. In 2011 Congress passed the Budget Control Act, which will require automatic across-the-board cuts, known as sequestration, and will take effect on 2 January 2013. Estimated cuts of $1.2 trillion and discretionary spending caps set at Fiscal Year 2012 levels will trigger non-defense program cuts of 9.8% in the first year as reported by the Congressional Research Service. Funding from non-defense program agencies such as NSF, NASA, DOE, NOAA, USGS, and others drive science and technological innovation, support public safety, create jobs, educate generations of scientists, stimulate the economy, protect our environment, and enrich lives. With non-defense discretionary programs representing less than one-fifth of the federal budget, severe cuts to these programs will not alleviate our deficit, but instead restrict our growth.

Fire history at the eastern Great Plains margin, Missouri River Loess Hills

Treesearch

Michael C. ​Stambaugh; Richard P. Guyette; Erin R. McMurry; Daniel C. Dey

2006-01-01

The purpose of this paper is to provide quantitative fire history information for a geographically unique region, the Loess Hills of northwest Missouri. We sampled 33 bur oak (Quercus macrocarpa Michx.), chinkapin oak (Q. muehlenbergii Engelm.), and black oak (Q. velutina Lam.) trees from the Brickyard Hill...

78 FR 9418 - National Register of Historic Places; Notification of Pending Nominations and Related Actions

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-08

... County Rock Hill Printing and Finishing Company, 400 W. White St., Rock Hill, 12001264 VIRGINIA Augusta... Ellen Henderson, House, 307 S. Maple Ave., Falls Church (Independent City), 12001267 Franklin..., 1739 Jefferson Davis Hwy., Stafford, 12001272 Virginia Beach Independent City Green Hill, 1721 Lovetts...

83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

83. GENERAL VIEW FROM NORTH END OF GUN HILL PLATFORM OF 3RD AVENUE EL SHOWING THE SOUTHBOUND TRACK APPROACH INTO GUN HILL STATION. 7TH AVENUE EXPRESS EL ABOVE. - Interborough Rapid Transit Company, Third Avenue Elevated Line, Borough of the Bronx, New York County, NY

78 FR 72914 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-04

.... Forest Hill, Hill, TX 76119. 3219 California Parkway, Forest Hill, TX 76119. Travis City of Austin (13..., Austin, TX Road, 12th 78767. Floor, Austin, TX 78704. Travis Unincorporated The Honorable Travis County..., 700 Austin, TX 78767. Lavaca Street, 5th Floor, Suite 540, Austin, TX 78701. Williamson City of...

The Camp Hill Project: Objectives and Design

ERIC Educational Resources Information Center

Mattingly, John B.

1976-01-01

Available from: EC 090 474. Outlined are the problems and objectives of Pennsylvania's Camp Hill Project--a program designed to complete psychological needs assessments for juveniles incarcerated at Camp Hill, to develop project policies and guidelines in preparation for meeting with juvenile court judges, and to hire staff. (SBH)

"This Delightfull Garden": "Rabbit Hill" and the Pastoral Tradition.

ERIC Educational Resources Information Center

Jordan, Anne Devereaux

1997-01-01

Contends that Robert Lawson's children's book "Rabbit Hill" (1944) falls within the genre of pastoral literature, in the tradition of Edmund Spenser's "Faerie Queen." Examines the history of the genre and finds reasons for classifying Lawson's book as pastoral. Cites classic elements in "Rabbit Hill." Gives five…

76 FR 62461 - Post Office Closing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-07

... POSTAL REGULATORY COMMISSION [Docket No. A2011-97; Order No. 890] Post Office Closing AGENCY... the closing of the Oak Hill, Alabama post office has been filed. It identifies preliminary steps and... determination to close the Oak Hill post office in Oak Hill, Alabama. The petition for review was filed by the...

7. Photographic copy of construction drawing 6912132 (from record group ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. Photographic copy of construction drawing 6912132 (from record group of Civil Engineering, Hill Air Force Base, Utah). 1940. 8'x10' negative and print. HILL FIELD, UTAH, QM GAS & OIL HOUSE PLAN, ELEVATIONS, DETAIL & STRUCTURAL. - Hill Field, Quatermaster Gas & Oil House, 7326 Wardleigh Road, Layton, Davis County, UT

Evidence for Acid-Sulfate Alteration in the Pahrump Hills Region, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Ming, D. W.; Blake, D. F.; Morris, R. V.; Bish, D. L.; Bristow, T. F.; Crisp, J. A.; Morookian, J. M.; Vaniman. D. T.; Chipera, S. J.;

On the spread of changes in marine low cloud cover in climate model simulations of the 21st century

NASA Astrophysics Data System (ADS)

Qu, Xin; Hall, Alex; Klein, Stephen A.; Caldwell, Peter M.

2014-05-01

In 36 climate change simulations associated with phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5), changes in marine low cloud cover (LCC) exhibit a large spread, and may be either positive or negative. Here we develop a heuristic model to understand the source of the spread. The model's premise is that simulated LCC changes can be interpreted as a linear combination of contributions from factors shaping the clouds' large-scale environment. We focus primarily on two factors—the strength of the inversion capping the atmospheric boundary layer (measured by the estimated inversion strength, EIS) and sea surface temperature (SST). For a given global model, the respective contributions of EIS and SST are computed. This is done by multiplying (1) the current-climate's sensitivity of LCC to EIS or SST variations, by (2) the climate-change signal in EIS or SST. The remaining LCC changes are then attributed to changes in greenhouse gas and aerosol concentrations, and other environmental factors. The heuristic model is remarkably skillful. Its SST term dominates, accounting for nearly two-thirds of the intermodel variance of LCC changes in CMIP3 models, and about half in CMIP5 models. Of the two factors governing the SST term (the SST increase and the sensitivity of LCC to SST perturbations), the SST sensitivity drives the spread in the SST term and hence the spread in the overall LCC changes. This sensitivity varies a great deal from model to model and is strongly linked to the types of cloud and boundary layer parameterizations used in the models. EIS and SST sensitivities are also estimated using observational cloud and meteorological data. The observed sensitivities are generally consistent with the majority of models as well as expectations from prior research. Based on the observed sensitivities and the relative magnitudes of simulated EIS and SST changes (which we argue are also physically reasonable), the heuristic model predicts LCC will decrease over the 21st-century. However, to place a strong constraint, for example on the magnitude of the LCC decrease, will require longer observational records and a careful assessment of other environmental factors producing LCC changes. Meanwhile, addressing biases in simulated EIS and SST sensitivities will clearly be an important step towards reducing intermodel spread in simulated LCC changes.

WASS: an open-source stereo processing pipeline for sea waves 3D reconstruction

NASA Astrophysics Data System (ADS)

Bergamasco, Filippo; Benetazzo, Alvise; Torsello, Andrea; Barbariol, Francesco; Carniel, Sandro; Sclavo, Mauro

2017-04-01

Stereo 3D reconstruction of ocean waves is gaining more and more popularity in the oceanographic community. In fact, recent advances of both computer vision algorithms and CPU processing power can now allow the study of the spatio-temporal wave fields with unprecedented accuracy, especially at small scales. Even if simple in theory, multiple details are difficult to be mastered for a practitioner so that the implementation of a 3D reconstruction pipeline is in general considered a complex task. For instance, camera calibration, reliable stereo feature matching and mean sea-plane estimation are all factors for which a well designed implementation can make the difference to obtain valuable results. For this reason, we believe that the open availability of a well-tested software package that automates the steps from stereo images to a 3D point cloud would be a valuable addition for future researches in this area. We present WASS, a completely Open-Source stereo processing pipeline for sea waves 3D reconstruction, available at http://www.dais.unive.it/wass/. Our tool completely automates the recovery of dense point clouds from stereo images by providing three main functionalities. First, WASS can automatically recover the extrinsic parameters of the stereo rig (up to scale) so that no delicate calibration has to be performed on the field. Second, WASS implements a fast 3D dense stereo reconstruction procedure so that an accurate 3D point cloud can be computed from each stereo pair. We rely on the well-consolidated OpenCV library both for the image stereo rectification and disparity map recovery. Lastly, a set of 2D and 3D filtering techniques both on the disparity map and the produced point cloud are implemented to remove the vast majority of erroneous points that can naturally arise while analyzing the optically complex nature of the water surface (examples are sun-glares, large white-capped areas, fog and water areosol, etc). Developed to be as fast as possible, WASS can process roughly four 5 MPixel stereo frames per minute (on a consumer i7 CPU) to produce a sequence of outlier-free point clouds with more than 3 million points each. Finally, it comes with an easy to use user interface and designed to be scalable on multiple parallel CPUs.

The role of the global electric circuit in solar and internal forcing of clouds and climate

NASA Astrophysics Data System (ADS)

Tinsley, Brian A.; Burns, G. B.; Zhou, Limin

Reports of a variety of short-term meteorological responses to changes in the global electric circuit associated with a set of disparate inputs are analyzed. The meteorological responses consist of changes in cloud cover, atmospheric temperature, pressure, or dynamics. All of these are found to be responding to changes in a key linking agent, that of the downward current density, Jz, that flows from the ionosphere through the troposphere to the surface (ocean and land). As it flows through layer clouds, Jz generates space charge in conductivity gradients at the upper and lower boundaries, and this electrical charge is capable of affecting the microphysical interactions between droplets and both ice-forming nuclei and condensation nuclei. Four short-term inputs to the global circuit are due to solar activity and consist of (1) Forbush decreases of the galactic cosmic ray flux; (2) solar energetic particle events; (3) relativistic electron precipitation changes; and (4) polar cap ionospheric convection potential changes. One input that is internal to the global circuit consists of (5) global ionospheric potential changes due to changes in the current output of the highly electrified clouds (mainly deep convective clouds at low latitudes) that act as generators for the circuit. The observed short-term meteorological responses to these five inputs are of small amplitude but high statistical significance for repeated Jz changes of order 5% for low latitudes increasing to 25-30% at high latitudes. On the timescales of multidecadal solar minima, such as the Maunder minimum, changes in tropospheric dynamics and climate related to Jz are also larger at high latitudes, and correlate with the lower energy component (˜1 GeV) of the cosmic ray flux increasing by as much as a factor of two relative to present values. Also, there are comparable cosmic ray flux changes and climate responses on millennial timescales. The persistence of the longer-term Jz changes for many decades to many centuries would produce an integrated effect on climate that could dominate over short-term weather and climate variations, and explain the observed correlations. Thus, we propose that mechanisms responding to Jz are a candidate for explanations of sun-weather-climate correlations on multidecadal to millenial timescales, as well as on the day-to-day timescales analyzed here.

Observations of cloud chemistry during longrange transport of power plant plumes

NASA Astrophysics Data System (ADS)

Clark, P. A.; Fletcher, I. S.; Kallend, A. S.; McElroy, W. J.; Marsh, A. R. W.; Webb, A. H.

Measurements of the chemical composition of cloud water have been made as part of a programme to study the chemical development of power plant plumes in trajectories over the North Sea. During a two-day study (28-29 January 1981), the conditions were anticyclonic with light winds advecting the plume from the NE coast of England towards Denmark. The mixing layer overland was capped by stratocumulus beneath a very strong subsidence inversion, which resulted in the plume being entirely trapped within the layer. Low level acceleration occurred as the plume travelled towards the coast, accompanied by a shallowing of the mixing layer. This led to the unusual situation whereby the plume was confined to a shallow (400m) stratocumulus-filled boundary layer throughout most of its travel. The light winds enabled approximately Lagrangian sampling of the plume after about 5 and 22 h travel (~ 100 and 650km from source). The very shallow boundary layer constrained the dilution of the plume to such an extent that even though ambient O 3 was consumed within the plume by the reaction with NO, the NO 2/NO x ratio was still < 0.5 along the plume centre line after 22 h travel. The measurements have been compared with the predictions of a reactive plume model involving both gas phase and solution phase chemistry. The model predicts oxidation rates for SO 2 in the ambient air outside the plume to be substantially higher than those within the plume, at values of 0.5-1.0 and ~ 0.04 % h -1, respectively. This leads to the conclusion that nearly all the sulphate in the plume arose from entrainment of sulphate produced in cloud droplets outside the plume. The absence of an effective oxidation mechanism in solution for the conversion of NOx to HNO 3 suggests that nitrate in the cloud water was derived from the gas phase oxidation of NOx. HC1 was found to be the major contributor to cloud water acidity in the plume on this occasion. The resultant acidity suppressed the solubility of SO 2 and this together with the low oxidant levels inhibited the production of sulphate in solution within the plume. The HCl contribution to acidity had declined markedly after 22h travel and this loss corresponds to a dry deposition velocity of 13 mm s -1.

Voluntary EMG-to-force estimation with a multi-scale physiological muscle model

PubMed Central

2013-01-01

Background EMG-to-force estimation based on muscle models, for voluntary contraction has many applications in human motion analysis. The so-called Hill model is recognized as a standard model for this practical use. However, it is a phenomenological model whereby muscle activation, force-length and force-velocity properties are considered independently. Perreault reported Hill modeling errors were large for different firing frequencies, level of activation and speed of contraction. It may be due to the lack of coupling between activation and force-velocity properties. In this paper, we discuss EMG-force estimation with a multi-scale physiology based model, which has a link to underlying crossbridge dynamics. Differently from the Hill model, the proposed method provides dual dynamics of recruitment and calcium activation. Methods The ankle torque was measured for the plantar flexion along with EMG measurements of the medial gastrocnemius (GAS) and soleus (SOL). In addition to Hill representation of the passive elements, three models of the contractile parts have been compared. Using common EMG signals during isometric contraction in four able-bodied subjects, torque was estimated by the linear Hill model, the nonlinear Hill model and the multi-scale physiological model that refers to Huxley theory. The comparison was made in normalized scale versus the case in maximum voluntary contraction. Results The estimation results obtained with the multi-scale model showed the best performances both in fast-short and slow-long term contraction in randomized tests for all the four subjects. The RMS errors were improved with the nonlinear Hill model compared to linear Hill, however it showed limitations to account for the different speed of contractions. Average error was 16.9% with the linear Hill model, 9.3% with the modified Hill model. In contrast, the error in the multi-scale model was 6.1% while maintaining a uniform estimation performance in both fast and slow contractions schemes. Conclusions We introduced a novel approach that allows EMG-force estimation based on a multi-scale physiology model integrating Hill approach for the passive elements and microscopic cross-bridge representations for the contractile element. The experimental evaluation highlights estimation improvements especially a larger range of contraction conditions with integration of the neural activation frequency property and force-velocity relationship through cross-bridge dynamics consideration. PMID:24007560

Titan's geoid and hydrology: implications for Titan's geological evolution

NASA Astrophysics Data System (ADS)

Sotin, Christophe; Seignovert, Benoit; Lawrence, Kenneth; MacKenzie, Shannon; Barnes, Jason; Brown, Robert

2014-05-01

A 1x1 degree altitude map of Titan is constructed from the degree 4 gravity potential [1] and Titan's shape [2] determined by the Radio Science measurements and RADAR observations of the Cassini mission. The amplitude of the latitudinal altitude variations is equal to 300 m compared to 600 m for the amplitude of the latitudinal shape variations. The two polar caps form marked depressions with an abrupt change in topography at exactly 60 degrees at both caps. Three models are envisaged to explain the low altitude of the polar caps: (i) thinner ice crust due to higher heat flux at the poles, (ii) fossil shape acquired if Titan had higher spin rate in the past, and (iii) subsidence of the crust following the formation of a denser layer of clathrates as ethane rain reacts with the H2O ice crust [3]. The later model is favored because of the strong correlation between the location of the cloud system during the winter season and the latitude of the abrupt change in altitude. Low altitude polar caps would be the place where liquids would run to and eventually form large seas. Indeed, the large seas of Titan are found at the deepest locations at the North Pole. However, the lakes and terrains considered to be evaporite candidates due to their spectral characteristics in the infrared [4,5] seem to be perched. Lakes may have been filled during Titan's winter and then slowly evaporated leaving material on the surface. Interestingly, the largest evaporite deposits are located at the equator in a deep depression 150 m below the altitude of the northern seas. This observation seems to rule out the presence of a global subsurface hydrocarbon reservoir unless the evaporation rate at the equator is faster than the transport of fluids from the North Pole to the equator. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Iess L. et al. (2012) Science, doi 10.1126/science.1219631. [2] Lorenz R.D. (2013) Icarus, 225, 367-377. [3] Choukroun M. and C. Sotin (2012) Geophys. Res. Lett., 39, L0420. [4] Barnes J.W. et al. (2011) Icarus, 216, 136-140. [5] MacKenzie S.M. et al. (2014) submitted to JGR.

Computational tools for fitting the Hill equation to dose-response curves.

PubMed

Gadagkar, Sudhindra R; Call, Gerald B

2015-01-01

Many biological response curves commonly assume a sigmoidal shape that can be approximated well by means of the 4-parameter nonlinear logistic equation, also called the Hill equation. However, estimation of the Hill equation parameters requires access to commercial software or the ability to write computer code. Here we present two user-friendly and freely available computer programs to fit the Hill equation - a Solver-based Microsoft Excel template and a stand-alone GUI-based "point and click" program, called HEPB. Both computer programs use the iterative method to estimate two of the Hill equation parameters (EC50 and the Hill slope), while constraining the values of the other two parameters (the minimum and maximum asymptotes of the response variable) to fit the Hill equation to the data. In addition, HEPB draws the prediction band at a user-defined confidence level, and determines the EC50 value for each of the limits of this band to give boundary values that help objectively delineate sensitive, normal and resistant responses to the drug being tested. Both programs were tested by analyzing twelve datasets that varied widely in data values, sample size and slope, and were found to yield estimates of the Hill equation parameters that were essentially identical to those provided by commercial software such as GraphPad Prism and nls, the statistical package in the programming language R. The Excel template provides a means to estimate the parameters of the Hill equation and plot the regression line in a familiar Microsoft Office environment. HEPB, in addition to providing the above results, also computes the prediction band for the data at a user-defined level of confidence, and determines objective cut-off values to distinguish among response types (sensitive, normal and resistant). Both programs are found to yield estimated values that are essentially the same as those from standard software such as GraphPad Prism and the R-based nls. Furthermore, HEPB also has the option to simulate 500 response values based on the range of values of the dose variable in the original data and the fit of the Hill equation to that data. Copyright © 2014. Published by Elsevier Inc.

Classification of Broken Hill-Type Pb-Zn-Ag Deposits: A Refinement

NASA Astrophysics Data System (ADS)

Spry, P. G.; Teale, G. S.; Steadman, J. A.

2009-05-01

Broken Hill Hill-type Pb-Zn-Ag (BHT) deposits constitute some of the largest ore deposits in the world. The Broken Hill deposit is the largest accumulation of Pb, Zn, and Ag on Earth and the Cannington deposit is currently the largest silver deposit. Characteristic features of BHT deposits include: 1. high Pb+Zn+Ag values with Pb > Zn; 2. Metamorphism to amphibolite-granulite facies; 3. Paleo-to Mesoprotoerozoic clastic metasedimentary host rocks; 4. Sulfides that are spatially associated with bimodal (felsic and mafic) volcanic rocks, and stratabound gahnite- and garnet-bearing rocks and iron formations, 5. Stacked orebodies with characteristic Pb:Zn:Ag ratios and skarn-like Fe-Mn-Ca-F gangue assemblages, and the presence of Cu, Au, Bi, As, and Sb; and 6. Sulfur-poor assemblages. Broken Hill (Australia) has a prominent footwall feeder zone whereas other BHT deposits have less obvious alteration zones (footwall garnet spotting and stratabound alteration haloes). Deposits previously regarded in the literature as BHT deposits are Broken Hill, Cannington, Oonagalabie, Menninie Dam, and Pegmont (Australia), Broken Hill, Swartberg, Big Syncline, and Gamsberg (South Africa), Zinkgruvan (Sweden), Sullivan, Cottonbelt, and Foster River (Canada), and Boquira (Brazil). Of these deposits, only the Broken Hill (Australia, South Africa), Pinnacles, Cannington, Pegmont, and Swartberg deposits are BHT deposits. Another BHT deposit includes the Green Parrot deposit, Jervois Ranges (Northern Territory). The Foster River, Gamsberg, and Sullivan deposits are considered to be "SEDEX deposits with BHT affinities", and the Oonagalabie, Green Mountain (Colorado), and Zinkgruvan are "VMS deposits with BHT affinities". In the Broken Hill area (Australia), Corruga-type Pb-Zn-Ag deposits occur in calc-silicate rocks and possess some BHT characteristics; the Big Syncline, Cottonbelt, Menninie Dam, and Saxberget deposits are Corruga-type deposits. SEDEX deposits with BHT affinities, VMS deposits with BHT affinities, and Corruga-type deposits represent transitional deposits between BHT and SEDEX, VMS, and metamorphosed base metal calc-silicate deposits, respectively. Although the non-sulfide zinc deposits at Franklin Furnace and Sterling Hill, NJ, do not contain Pb, they resemble sulfur-poor BHT deposits.

Ecology, silviculture, and management of Black Hills ponderosa pine

Treesearch

Wayne D. Shepperd; Michael A. Battaglia

2002-01-01

This paper presents a broad-based synthesis of the general ecology of the ponderosa pine ecosystem in the Black Hills. This synthesis contains information and results of research on ponderosa pine from numerous sources within the Black Hills ecosystem. We discuss the silvical characteristics of ponderosa pine, natural disturbances that govern ecosystem processes,...

76 FR 58257 - Combined Notice of Filings #2

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-20

... Hills Wind Farm, LLC. Description: Smoky Hills Wind Farm, LLC submits tariff filing per 35.1: Smoky Hills Wind Farm, LLC MBR Tariff to be effective 10/31/2007. Filed Date: 09/12/2011. Accession Number... Associates, L.P., Golden Spread Panhandle Wind Ranch, LLC. Description: Notice of Change in Status of Golden...

76 FR 76393 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-07

...; ER11-4499-002; ER11-4500-002; ER11- 4507-002; ER11-4501-002. Applicants: Smoky Hills Wind Farm, LLC, Smoky Hills Wind Project II, LLC, Enel Stillwater, LLC, Caney River Wind Project, LLC, Canastota Windpower, LLC. Description: Notice of Non-Material Change in Status re Smoky Hills Wind Farm, LLC, et al...

24 CFR 100.303 - 62 or over housing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Mary, it might qualify for the “55 or over” exemption in § 100.304. Example (2): The Blueberry Hill... persons who were all 62 years of age or older. Blueberry Hill can qualify for the “62 or over” exemption... leave for Blueberry Hill to qualify for the “62 or over” exemption. ...

24 CFR 100.303 - 62 or over housing.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Mary, it might qualify for the “55 or over” exemption in § 100.304. Example (2): The Blueberry Hill... persons who were all 62 years of age or older. Blueberry Hill can qualify for the “62 or over” exemption... leave for Blueberry Hill to qualify for the “62 or over” exemption. ...

24 CFR 100.303 - 62 or over housing.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Mary, it might qualify for the “55 or over” exemption in § 100.304. Example (2): The Blueberry Hill... persons who were all 62 years of age or older. Blueberry Hill can qualify for the “62 or over” exemption... leave for Blueberry Hill to qualify for the “62 or over” exemption. ...

24 CFR 100.303 - 62 or over housing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Mary, it might qualify for the “55 or over” exemption in § 100.304. Example (2): The Blueberry Hill... persons who were all 62 years of age or older. Blueberry Hill can qualify for the “62 or over” exemption... leave for Blueberry Hill to qualify for the “62 or over” exemption. ...

24 CFR 100.303 - 62 or over housing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Mary, it might qualify for the “55 or over” exemption in § 100.304. Example (2): The Blueberry Hill... persons who were all 62 years of age or older. Blueberry Hill can qualify for the “62 or over” exemption... leave for Blueberry Hill to qualify for the “62 or over” exemption. ...

33 CFR 80.145 - Race Point, MA, to Watch Hill, RI.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Race Point, MA, to Watch Hill, RI. 80.145 Section 80.145 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.145 Race Point, MA, to Watch Hill...

33 CFR 80.145 - Race Point, MA, to Watch Hill, RI.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Race Point, MA, to Watch Hill, RI. 80.145 Section 80.145 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.145 Race Point, MA, to Watch Hill...

33 CFR 80.145 - Race Point, MA, to Watch Hill, RI.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Race Point, MA, to Watch Hill, RI. 80.145 Section 80.145 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.145 Race Point, MA, to Watch Hill...

33 CFR 80.145 - Race Point, MA, to Watch Hill, RI.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Race Point, MA, to Watch Hill, RI. 80.145 Section 80.145 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.145 Race Point, MA, to Watch Hill...

33 CFR 80.145 - Race Point, MA, to Watch Hill, RI.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Race Point, MA, to Watch Hill, RI. 80.145 Section 80.145 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Atlantic Coast § 80.145 Race Point, MA, to Watch Hill...

77 FR 47625 - Laurel Hill Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2313-000] Laurel Hill Wind Energy, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request For... Laurel Hill Wind Energy, LLC's application for market-based rate authority, with an accompanying rate...

Hospital/Health Facilities and the Hill-Burton Obligations: A Secret from the Black Community.

ERIC Educational Resources Information Center

Rice, Mitchell F.

1986-01-01

Uncompensated/free care and community service obligations under the Hill-Burton Act can assist substantially in providing needed health care services to the Black community. Blacks, however, must become knowledgeable about these obligations, develop monitoring projects, and be prepared to take legal steps to bring Hill-Burton facilities into…

78 FR 13870 - Roberto Sella; Notice of Declaration of Intention and Soliciting Comments, Protests, and/or...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-01

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. DI13-3-000] Roberto Sella... 7, 2012. d. Applicant: Roberto Sella. e. Name of Project: Hydro-electric and Geothermal Alternative Energy System at Paper Hill Farm (Paper Hill Farm). f. Location: The proposed Paper Hill Farm project...

76 FR 35396 - Black Hills National Forest, Mystic Ranger District, South Dakota, Section 30 Limestone Mining...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

... DEPARTMENT OF AGRICULTURE Forest Service Black Hills National Forest, Mystic Ranger District... INFORMATION CONTACT: Dave Slepnikoff, Project Coordinator, Black Hills National Forest, Mystic Ranger District... regulations at 36 CFR 228 Subpart A. The Project is located between Rapid City and Black Hawk, South Dakota...

76 FR 5580 - Black Hills Colorado IPP, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-01

... proceeding Black Hills Colorado IPP, LLC's application for market-based rate authority, with an accompanying... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2724-000] Black Hills Colorado IPP, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket...

Case Study on Education Opportunities for Hill Tribes in Northern Thailand: Implications for Sustainable Rural Development.

ERIC Educational Resources Information Center

Fujioka, Rika

This research analyzes the impact of the Thai government's activities to promote educational opportunities for people of the northern hill tribes. In addition to interviews with government and nongovernmental organization staff, field surveys were conducted in hill tribe villages. The introductory chapter provides background information on the…

76 FR 6457 - Hill-Lake Gas Storage, LLC; Notice of Baseline Filings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-04

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-134-001] Hill-Lake Gas Storage, LLC; Notice of Baseline Filings January 31, 2011. Take notice that on January 28, 2011, Hill-Lake submitted a revised baseline filing of their Statement of Operating Conditions for services provided under...

76 FR 30338 - Hill-Lake Gas Storage, LLC; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-25

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR11-110-000] Hill-Lake Gas Storage, LLC; Notice of Filing Take notice that on May 13, 2011, Hill-Lake Gas Storage, LLC filed to update its address and to clarify definitions for Maximum Daily Withdrawal Quantity and Maximum Daily...

76 FR 7186 - Hill-Lake Gas Storage, LLC; Notice of Baseline Filings

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-134-002] Hill-Lake Gas Storage, LLC; Notice of Baseline Filings February 2, 2011. Take notice that on February 1, 2011, Hill-Lake submitted a revised baseline filing of their Statement of Operating Conditions for services provided under...

OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

OVERVIEW OF GOLD HILL MILL, ROAD, AND WHITE PINE TALC MINE LOOKING EAST. THE OPENING TO THE TALC MINE IS IN THE DARK AREA AT CENTER LEFT EDGE. WARM SPRINGS CAMP IS OUT OF FRAME TO THE RIGHT. - Gold Hill Mill, Warm Spring Canyon Road, Death Valley Junction, Inyo County, CA

Report on the Black Hills Alliance.

ERIC Educational Resources Information Center

Ryan, Joe

1979-01-01

A rally to save the Black Hills from coal- and uranium-greedy energy companies was held on July 6 and over 2,000 joined in a 15-mile walk on July 7 in Rapid City, South Dakota. The Black Hills Alliance, an Indian coalition concerned about energy development proposals in the Great Plains, sponsored the gathering. (NQ)

1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. BUNKER HILL LEAD SMELTER. VIEW IS FROM CENTRAL IMPOUNDMENT AREA LOOKING SOUTH. PLANT DRY IS IN CENTER FOREGROUND, SLAG FUMING PLANT IS IN RIGHT FOREGROUND, AND BAG HOUSE IS IN RIGHT BACKGROUND. VARIOUS PLANT STACKS ARE ALSO VISIBLE. - Bunker Hill Lead Smelter, Bradley Rail Siding, Kellogg, Shoshone County, ID

78 FR 18241 - Approval and Promulgation of Air Quality Implementation Plans; Minnesota; Flint Hills Resources...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-26

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R05-OAR-2011-0328; FRL-9792-8] Approval and Promulgation of Air Quality Implementation Plans; Minnesota; Flint Hills Resources Pine Bend AGENCY... rule approving a revision to the the Minnesota sulfur dioxide SIP for Flint Hills Resources Pine Bend...

The Bradford Hill criteria and zinc-induced anosmia: a causality analysis.

PubMed

Davidson, Terence M; Smith, Wendy M

2010-07-01

To apply the Bradford Hill criteria, which are widely used to establish causality between an environmental agent and disease, to evaluate the relationship between over-the-counter intranasal zinc gluconate therapy and anosmia. Patient and literature review applying the Bradford Hill criteria on causation. University of California, San Diego, Nasal Dysfunction Clinic. The study included 25 patients who presented to the University of California, San Diego, Nasal Dysfunction Clinic complaining of acute-onset anosmia after intranasal application of homeopathic zinc gluconate gel. Each of the 9 Bradford Hill criteria--strength of association, consistency, specificity, temporality, biological gradient (dose-response), biological plausibility, biological coherence, experimental evidence, and analogy--was applied to intranasal zinc gluconate therapy and olfactory dysfunction using published, peer-reviewed medical literature and reported clinical experiences. Clinical, biological, and experimental data support the Bradford Hill criteria to demonstrate that intranasal zinc gluconate therapy causes hyposmia and anosmia. The Bradford Hill criteria represent an important tool for scientifically determining cause between environmental exposure and disease. Increased Food and Drug Administration oversight of homeopathic medications is needed to monitor the safety of these popular remedies.

Visualizing inequality

NASA Astrophysics Data System (ADS)

Eliazar, Iddo

2016-07-01

The study of socioeconomic inequality is of substantial importance, scientific and general alike. The graphic visualization of inequality is commonly conveyed by Lorenz curves. While Lorenz curves are a highly effective statistical tool for quantifying the distribution of wealth in human societies, they are less effective a tool for the visual depiction of socioeconomic inequality. This paper introduces an alternative to Lorenz curves-the hill curves. On the one hand, the hill curves are a potent scientific tool: they provide detailed scans of the rich-poor gaps in human societies under consideration, and are capable of accommodating infinitely many degrees of freedom. On the other hand, the hill curves are a powerful infographic tool: they visualize inequality in a most vivid and tangible way, with no quantitative skills that are required in order to grasp the visualization. The application of hill curves extends far beyond socioeconomic inequality. Indeed, the hill curves are highly effective 'hyperspectral' measures of statistical variability that are applicable in the context of size distributions at large. This paper establishes the notion of hill curves, analyzes them, and describes their application in the context of general size distributions.

Geologic and paleoecologic studies of the Nebraska Sand Hills

USGS Publications Warehouse

Ahlbrandt, Thomas S.; Fryberger, S.G.; Hanley, John H.; Bradbury, J. Platt

1980-01-01

PART A: The Nebraska Sand Hills are an inactive, late Quaternary, most probably Holocene, dune field (covering 57,000 km 2 ) that have been eroded along streams and in blowouts, resulting in excellent lateral and vertical exposures of the stratification of dune and interdune sediments. This paper presents new data on the geometry, primary sedimentary structures, modification of sedimentary structures, direction of sand movement, and petrography of these eolian deposits. Eolian deposits of the Sand Hills occur as relatively thin (9-24 m) 'blanket' sands, composed of a complex of dune and discontinuous, diachronous interdune deposits unconformably overlying fluviolacustrine sediments. The internal stratification of large dunes in the Sand Hills (as high as 100 m), is similar to the internal stratification of smaller dunes of the same type in the Sand Hills, differing only in scale. Studies of laminae orientation in the Sand Hills indicate that transverse, barchan, and blowout dunes can be differentiated in rocks of eolian origin using both the mean dip angle of laminae and the mean angular deviation of dip direction. A variety of secondary structures modify or replace primary eolian stratification in the Sand Hills, the more common of which are dissipation structures and bioturbation. Dissipation structures in the Sand Hills may develop when infiltrating water deposits clay adjacent to less permeable layers in the sand, or along the upper margins of frozen layers that form in the sands during winter. Cross-bed measurements from dunes of the Nebraska Sand Hills necessitate a new interpretation of the past sand transport directions. The data from these measurements indicate a general northwest-to-southeast drift of sand, with a more southerly drift in the southeast part of the Sand Hills. A large area of small dunes < 100 m high) described by Smith (1965) as linear or seif in the central part of the Sand Hills was interpreted by him on the basis of morphology only. We interpret these as transverse-ridge dunes that were generally moving to the south. Further, our measurements indicate that dunes in the western part of the Sand Hills did not develop in response to present-day effective wind regimes. The presence of 'transverse' and en echelon barchan dunes in the Sand Hills corresponds to a developmental sequence of barchan to linear dunes proposed by Tsoar (1978). Dune and interdune deposits of the Sand Hills are subfeldsarenites to feldsarenites. Sand grains are commonly coated with montmorillonitic clay, which may be the local source of the clay concentrated in the dissipation structures. Textures of sand samples taken from adjacent layers within a dune were as dissimilar as textures of samples taken from widely separated dunes. This common occurrence indicates that textural data must be used carefully and in combination with other data to recognize ancient rocks of eolian origin. Organic material derived from a variety of flora and fauna that inhabit the interdunes (chapters B and C) generated both oil and gas upon heating. Thus, interdune sediments may be an indigenous hydrocarbon source if buried in eolianites. The twofold stratigraphy of loess and correlative dune deposits in the Sand Hills proposed by Reed and Dreeszen (1965) could not be confirmed by the present study. Rather, available data indicate that the dunes represent a single formation as suggested by Lugn (1935). PART B: Three assemblages of nonmarine Mollusca from paleointerdune deposits in the Nebraska Sand Hills inhabited shallow, quiet, vegetated, subpermanent or temporary, freshwater interdune ponds and adjacent terrestrial habitats. Analysis of factors affecting the taxonomic composition, diversity, and abundance of species in living assemblages of mollusks support this interpretation. The mollusks have long biostratigraphic ranges and broad biogeographic distributions. They fail to establish precise age relations of the faunas othe

Distance-Based Functional Diversity Measures and Their Decomposition: A Framework Based on Hill Numbers

PubMed Central

Chiu, Chun-Huo; Chao, Anne

2014-01-01

Hill numbers (or the “effective number of species”) are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify “the effective number of equally abundant and (functionally) equally distinct species” in an assemblage. We also propose a class of mean functional diversity (per species), which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total) functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity) quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma) can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation) measures, including N-assemblage functional generalizations of the classic Jaccard, Sørensen, Horn and Morisita-Horn similarity indices. The proposed measures are applied to artificial and real data for illustration. PMID:25000299

Distance-based functional diversity measures and their decomposition: a framework based on Hill numbers.

PubMed

Chiu, Chun-Huo; Chao, Anne

2014-01-01

Hill numbers (or the "effective number of species") are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify "the effective number of equally abundant and (functionally) equally distinct species" in an assemblage. We also propose a class of mean functional diversity (per species), which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total) functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity) quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma) can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation) measures, including N-assemblage functional generalizations of the classic Jaccard, Sørensen, Horn and Morisita-Horn similarity indices. The proposed measures are applied to artificial and real data for illustration.

Burden of hospitalized childhood community-acquired pneumonia: A retrospective cross-sectional study in Vietnam, Malaysia, Indonesia and the Republic of Korea

PubMed Central

Tan, Kah Kee; Dang, Duc Anh; Kim, Ki Hwan; Kartasasmita, Cissy; Zhang, Xu-Hao; Shafi, Fakrudeen; Yu, Ta-Wen; Ledesma, Emilio; Meyer, Nadia

2018-01-01

ABSTRACT Background: Few studies describe the community-acquired pneumonia (CAP) burden in children in Asia. We estimated the proportion of all CAP hospitalizations in children from nine hospitals across the Republic of Korea (high-income), Indonesia, Malaysia (middle-income), and Vietnam (low/middle-income). Methods: Over a one or two-year period, children <5 years hospitalized with CAP were identified using ICD-10 discharge codes. Cases were matched to standardized definitions of suspected (S-CAP), confirmed (C-CAP), or bacterial CAP (B-CAP) used in a pneumococcal conjugate vaccine efficacy study (COMPAS). Median total direct medical costs of CAP-related hospitalizations were calculated. Results: Vietnam (three centers): 7591 CAP episodes were identified with 4.3% (95% confidence interval 4.2;4.4) S-CAP, 3.3% (3.2;3.4) C-CAP and 1.4% (1.3;1.4) B-CAP episodes of all-cause hospitalization in children aged <5 years. The B-CAP case fatality rate (CFR) was 1.3%. Malaysia (two centers): 1027 CAP episodes were identified with 2.7% (2.6;2.9); 2.6% (2.4;2.8); 0.04% (0.04;0.1) due to S-CAP, C-CAP, and B-CAP, respectively. One child with B-CAP died. Indonesia (one center): 960 CAP episodes identified with 18.0% (17.0;19.1); 16.8% (15.8;17.9); 0.3% (0.2;0.4) due to S-CAP, C-CAP, and B-CAP, respectively. The B-CAP CFR was 20%. Korea (three centers): 3151 CAP episodes were identified with 21.1% (20.4;21.7); 11.8% (11.2;12.3); 2.4% (2.1;2.7) due to S-CAP, C-CAP, and B-CAP, respectively. There were no deaths. Costs: CAP-related hospitalization costs were highest for B-CAP episodes: 145.00 (Vietnam) to 1013.3 USD (Korea) per episode. Conclusion: CAP hospitalization causes an important health and cost burden in all four countries studied (NMRR-12-50-10793). PMID:29125809

New Downhole Strong-Motion Data Recorded at Tarzana Array

NASA Astrophysics Data System (ADS)

Graizer, V.; Shakal, A.; Haddadi, H.

2001-12-01

Significantly amplified ground accelerations at the Tarzana station were recorded during many, but not all, earthquakes (e.g., Shakal et al., 1988). Peak horizontal ground acceleration at the Tarzana station during the M7.1 Hector Mine earthquake was almost twice as large as the accelerations recorded at nearby stations. After the Northridge earthquake the California Strong Motion Instrumentation Program (CSMIP) significantly increased instrumentation at Tarzana to study the unusual site amplification effect. Current instrumentation at Tarzana consists of an accelerograph at the top of Tarzana hill (Tarzana - Cedar Hill B), a downhole instrument at 60 m depth, and an accelerograph at the foot of the hill (Tarzana - Clubhouse), 180 m from the Cedar Hill B station. The original station, Tarzana - Cedar Hill Nursery A, was lost in 1999 due to construction. Thirteen events, including the Hector Mine earthquake, were simultaneously recorded by these instruments at Tarzana. The downhole instrument (A) was used as a reference site to compare the amplification effects at the top of Tarzana hill (B) and at the foot of the hill (C). Spectral amplification from the bottom of the hole to the top of the hill (B/A) and to the foot of the hill (C/A) is similar along the component parallel to the strike of Tarzana hill. But B/A is almost double C/A along the component transverse to the strike of the hill in period range from 0.04 to 0.8 sec (1.2 to 25 Hz). Comparison of the response spectra demonstrates clear directional site response resonance (perpendicular to the strike of the hill) at Tarzana. In contrast to accelerations recorded during the Mw 7.1 Hector Mine earthquake (high frequency part of seismic signal), displacements (relatively low frequency part of seismic signal) demonstrate almost no site amplification from the bottom of the hole to the surface (B/A) at periods greater than 1.5 sec, in either direction. Ground displacements at other CSMIP downhole arrays which recorded the Hector Mine earthquake also demonstrate almost no near-surface site amplification at long periods. Comparison of empirical and theoretical site amplification effects at Tarzana was performed using SHAKE91 modeling motion separately in the longitudinal and transverse directions. The source of the site amplification that produces large motions at Tarzana is still under investigation. The topography, shear-wave velocity profile and three-dimensional structure of the site apparently all contribute to the higher amplification of ground motion at the Tarzana site. The studies of Tarzana were co-funded by CSMIP and by the National Science Foundation (NSF) through the Resolution of Site Response Issues from the Northridge Earthquake Project (ROSRINE).

Reconstructed Paleo-topography of the Columbia Hills, Mars

NASA Astrophysics Data System (ADS)

Cole, S. B.; Watters, W. A.; Aron, F.; Squyres, S. W.

2013-12-01

From June 2004 through March 2010, the Mars Exploration Rover Spirit conducted a detailed campaign examining the Columbia Hills of Gusev Crater. In addition to mineralogical and chemical investigations, Spirit's stereo panoramic (Pancam) and navigation (Navcam) cameras obtained over 7,000 images of geologic targets along the West Spur of the Columbia Hills and Husband Hill, the highest peak. We have analyzed the entirety of this dataset, which includes stereo coverage of several outcrop exposures with apparent bedding. We have measured the bedding plane orientations of hundreds of fine-scale (~1-100cm) features on all of the potentially in-place outcrops using Digital Terrain Models (DTMs) derived from the rover's Pancam stereo image data, and mapped these orientations on a regional HiRISE image and DTM. Assuming that the bedding material was deposited conformably on the topography at the time of emplacement, we reconstruct the paleo-topography of the Columbia Hills. Our reconstructed paleo-topography is similar to the modern shape of Husband Hill, but with steeper slopes, consistent with a substantial amount of erosion since deposition. The Columbia Hills are an irregular, nearly-triangular edifice of uncertain origin, situated near the center of the 160km-diameter crater and hypothesized to be either the remnant of a central peak structure, or overlapping crater rims. They span ~6.6 km in the northerly direction by ~3.6 km in the easterly direction, and rise 90m above the basaltic plains that fill the floor of Gusev Crater and embay the Hills. The topography is as irregular as the perimeter, and is cut by numerous valleys of varying lengths, widths, and directional trends. Along the traverse, Spirit examined several rock classes as defined by elemental abundances from the Alpha Particle X-ray Spectrometer (APXS) and identified remotely by the Miniature Thermal Emission Spectrometer (Mini-TES). Unlike the Gusev Plains, the rocks of the Columbia Hills show extensive evidence of aqueous alteration. Many of the outcrops are believed to have formed from volcanic and/or impact-related airfall material, which should drape the topography that existed at the time of emplacement. Outcrop bedding plane orientations are not consistent with the depositional material draping the current Columbia Hills edifice: dip magnitudes are steeper than the modern topographic slopes, and dip directions are not correlated with the modern topographic slope directions. There are, however, regional trends consistent with the outcrops draping an ancient underlying topography. Planes representing compositionally similar outcrops on the modern Husband Hill summit and to the northwest converge over the modern Tennessee Valley. If the paleo-structure culminated in the peak suggested by the bedding plane orientations, up to 100m of material may have been removed from the Columbia Hills.

Where were you when the sun went out?

NASA Astrophysics Data System (ADS)

1999-11-01

The total solar eclipse of 1999 will no doubt have left an impression on millions of people. Members of the Editorial Board for Physics Education share some of their feelings and memories of the event. Simon Carson writes: My children and I were at home in Driffield, East Yorkshire, on said day. Out we went in the back garden with our big refracting telescope and eight-year-old James's Early Learning Centre telescope (plastic, cheap and jolly good for the price!) and our special glasses. Come the witching hour, we trained our telescopes, with white card behind them, on the Sun. Gradually we saw the Moon's shadow edge across the Sun. As James said, `It went cold and dark and the picture on the card looked like a thin glowing line'. It was surprisingly impressive given the distance from totality. The most remarkable effect was the drop in temperature and the fact that our bright sunny mid-morning in August became more like a chilly autumn dusk. Katharine, age 6, remembers performing cartwheels in the dark! Bob Kibble writes: My partner Jean, and I, holidayed in Trier, Germany, just outside the path of totality. On the big day we awoke to rain and clouds, as did most of central Europe. The trusty motorbike, laden with a picnic and photographic gear, took us south into France. We stopped just outside Metz at a service station along with dozens of like-minded but damp and dismal onlookers. Cloud cover was layered with darker rain-bearing cloud drifting at the lowest level. Mobile phone links confirmed that it was raining in Paris, Dijon and Munich. We decided to settle for the event - at least there was a shop and `facilities'. We were joined by a group of bikers, two of whom had travelled 480 km from Denmark that very morning. The shifting cloud cover offered tantalising glimpses of the partial phase as the light level fell. There was nothing we could do but put our faith in the weather. Now you see it, now you don't. As darkness fell and the temperature likewise the strangest thing happened. Just as totality approached the cloud above seemed to thin out, enabling us to see the whole event. We watched in amazement as the last thin bright patch disappeared. There were cheers, horns sounding and applause as the full spectacle was revealed before us - two full minutes of totality. I took photographs through a 600 mm mirror lens, cursing the instability of my flimsy tripod but able to see prominences in some detail. Despite my forward planning the 36 exposure film ran out just as last contact appeared. The excitement of the event prevented any serious, logical and measured photography. I just fired away. As soon as last contact had passed, the clouds reformed and neither Sun nor Moon were seen again until later that afternoon. We had witnessed what is apparently known as the `Red Sea effect' and is caused by the localized cooling due to the umbral shadow `punching' a hole in the cloud cover. The event left us speechless, moved and tearful. Words seemed so inadequate. I had given a number of presentations leading up to this event but nothing could have prepared me for the experience of totality. Darkness came upon us so quickly that we were taken by surprise. Looking up above our heads meant that few of us had noticed the horizon. Friends who were not so lucky with the weather remarked on the beauty of the illuminated horizon. For us it was the nearest thing to a miracle we had ever seen. Roll on 2001! Helen Reynolds writes: My memory of the eclipse will be of lying in a field on a cliff in France staring out to sea. No-one prepares you for the moment of totality; the hairs on the back of your neck literally stand on end. This is not normal. The speed with which darkness falls is frightening. It is inconceivable that minutes ago there was 95%+ coverage of the Sun - the Moon seemed to have no effect and then, suddenly in all senses of the word, darkness literally falls from the sky. The sounds are unreal and the colours are nothing you have seen before. The calls and cries of the children are muted, cameras click but the sound is dulled. There seem to be bands of colours falling from the sky onto the horizon, pinks and a hint of that colour we call indigo. For once you do not try to work out why this is happening; there is so little time to soak up the moment before it is gone. The fastest two minutes of my life to date. Jill Membrey writes: I have to admit to a somewhat disappointing Eclipse experience! I had made the decision early on to travel down to Plymouth from Bristol, so as to be in the path of totality and share the event `at home' with my mother. The morning of 11 August dawned bright and we were eager with anticipation, but sadly the cloud thickened and deepened as the morning progressed. By 11 am the cloud cover was so thick that there was no indication of the Sun's position at all, let alone any of the phases. We had to resort to the television screen to find out what was actually going on. It was also difficult to tell whether the darkness was due to the normal Plymouth weather or to some other factor. However, by 11.12 it was sufficiently dark outside for us to trigger the security light when we went into the garden! I was quite amazed at how quickly the sky lightened afterwards, although we still never got a glimpse of the Sun. In fact I never saw any sunshine until I returned to Bristol that evening, and then heard my husband gloat over his experience of the (almost) total eclipse witnessed between the broken clouds over his office. Just typical! I knew I should have stayed in Bristol... Jonathan Allday writes: I went with my wife Carolyn on a package tour to Paris to see the eclipse. On the day itself we were taken by coach to a park just outside Rheims to see the totality. Apparently our tour company shifted 6000 people that day. As we were making our way to the park the clouds would open occasionally to give us a view of the partial phase. The traffic was heavy and we were far from sure that we would make it in time. I was fretting and weighing up trying to convince the driver to stop at any point to let us out at the moment of totality. However, we made it and the park was a wonderful vantage point. I will never forget the quiet that came over this huge park with thousands of people in it as totality came. I remember looking across the lake and seeing camera flashes going off as the darkness descended. Periodic announcements over the PA system kept track of what was happening and sensibly gave warnings about how to view the eclipse. I had sworn that I would not take any pictures, figuring that by the time I had sorted out exposures the eclipse would be over. As it turned out the clouds were light so that the totality could be viewed through them and picture taking was easy. Consequently I was lying on my back staring through the camera lens and firing off photographs when the orange tinted shadow edge arrived over the hills. I missed it. Totality itself was glimpsed along with the corona through hazy clouds but that was a wonderful sight. Conclusions - next time I want to see it with no clouds. Liz Whitelegg writes: I'd been preparing for eclipse day for a whole 12 months by reading articles and going to talks about the eclipse, buying the special glasses at the ASE annual meeting, talking to eclipse experts etc. I even secured accommodation in some `friends' holiday home in Cornwall by lending a hand in the restoration process the year before! Having spent the very same week in Cornwall in '98 when it was hot and sunny all week, I was convinced that the heavens would shine on us and we'd get a spectacular totality. However, it was not to be. The weather forecast was for cloud cover and showers - but the day before the event was lovely and sunny, so who believes in weather forecasts anyway? But as we scanned the sky on awakening on 11 August, it seems the Met Office had got it right for once. We stuck to our plan anyway and caught the local train from St Ives to Lelant in order to climb to the highest point for miles around - Trencrom hill where (on a clear day) there was a good view of the north and south Cornish coasts. We were not alone, however. Hundreds of others had the same idea and it was pretty crowded up there. As we waited on the crowed hill top the weather got wetter and wetter, and I wasn't very impressed with the New Age contingent who chanted and drummed to encourage the clouds to retreat - their `music' sounded more like a rain dance to me! The only comfort was the sight of the Radio 1 roadshow revellers, who were down the road at Marazion, getting a soaking too - the wonders of modern technology enabled us to watch them on top of the hill on a miniature TV! Well, it did get very dark and it was strange to see the flashes of hundreds of cameras going off all over the surrounding countryside. But I must admit that as I got soaked to the skin (I discovered that my rainproof jacket isn't!) and as the rain turned to hail as the temperature fell, I wondered what all the fuss was about. I was very glad to return to our friends' cottage and dry off. The real the highlight of the day was watching the latest Austin Powers film at the local cinema - so you can tell that the eclipse was a pretty disappointing experience! Norman Fancey writes: I was on a camp site in Austria just inside the boundary of totality. As a physicist, I was familiar with the theory and knew what to expect. Nevertheless, even in the period leading up to the total eclipse, I found the slowly increasing section being eaten out of the Sun's disc to be most interesting and the few seconds of totality and almost complete darkness to be an experience I will never forget. My previous reading about eclipses did not prepare me for the beautiful colours reflected from the clouds near to the line of sight to the Sun for the few minutes on either side of the few seconds of complete darkness. Philip Britton writes: What do I remember most about the eclipse? We were near Salzburg, on the School Venture Scout Expedition. The boys experienced the eclipse at altitude, passing between mountain huts, so it got very cold. Thin cloud made for good observation. With no artificial light it was certainly dark. But above all I remember teenage boys being impressed by something!

High Resolution Stratigraphic Mapping in Complex Terrain: A Comparison of Traditional Remote Sensing Techniques with Unmanned Aerial Vehicle - Structure from Motion Photogrammetry

NASA Astrophysics Data System (ADS)

Nesbit, P. R.; Hugenholtz, C.; Durkin, P.; Hubbard, S. M.; Kucharczyk, M.; Barchyn, T.

2016-12-01

Remote sensing and digital mapping have started to revolutionize geologic mapping in recent years as a result of their realized potential to provide high resolution 3D models of outcrops to assist with interpretation, visualization, and obtaining accurate measurements of inaccessible areas. However, in stratigraphic mapping applications in complex terrain, it is difficult to acquire information with sufficient detail at a wide spatial coverage with conventional techniques. We demonstrate the potential of a UAV and Structure from Motion (SfM) photogrammetric approach for improving 3D stratigraphic mapping applications within a complex badland topography. Our case study is performed in Dinosaur Provincial Park (Alberta, Canada), mapping late Cretaceous fluvial meander belt deposits of the Dinosaur Park formation amidst a succession of steeply sloping hills and abundant drainages - creating a challenge for stratigraphic mapping. The UAV-SfM dataset (2 cm spatial resolution) is compared directly with a combined satellite and aerial LiDAR dataset (30 cm spatial resolution) to reveal advantages and limitations of each dataset before presenting a unique workflow that utilizes the dense point cloud from the UAV-SfM dataset for analysis. The UAV-SfM dense point cloud minimizes distortion, preserves 3D structure, and records an RGB attribute - adding potential value in future studies. The proposed UAV-SfM workflow allows for high spatial resolution remote sensing of stratigraphy in complex topographic environments. This extended capability can add value to field observations and has the potential to be integrated with subsurface petroleum models.

ALMA Observations of Elias 2–24: A Protoplanetary Disk with Multiple Gaps in the Ophiuchus Molecular Cloud

NASA Astrophysics Data System (ADS)

Cieza, Lucas A.; Casassus, Simon; Pérez, Sebastian; Hales, Antonio; Cárcamo, Miguel; Ansdell, Megan; Avenhaus, Henning; Bayo, Amelia; Bertrang, Gesa H.-M.; Cánovas, Hector; Christiaens, Valentin; Dent, William; Ferrero, Gabriel; Gamen, Roberto; Olofsson, Johan; Orcajo, Santiago; Osses, Axel; Peña-Ramirez, Karla; Principe, David; Ruíz-Rodríguez, Dary; Schreiber, Matthias R.; van der Plas, Gerrit; Williams, Jonathan P.; Zurlo, Alice

2017-12-01

We present ALMA 1.3 mm continuum observations at 0\\buildrel{\\prime\\prime}\\over{.} 2 (25 au) resolution of Elias 2–24, one of the largest and brightest protoplanetary disks in the Ophiuchus Molecular Cloud, and we report the presence of three partially resolved concentric gaps located at ∼20, 52, and 87 au from the star. We perform radiative transfer modeling of the disk to constrain its surface density and temperature radial profile and place the disk structure in the context of mechanisms capable of forming narrow gaps such as condensation fronts and dynamical clearing by actively forming planets. In particular, we estimate the disk temperature at the locations of the gaps to be 23, 15, and 12 K (at 20, 52, and 87 au, respectively), very close to the expected snowlines of CO (23–28 K) and N2 (12–15 K). Similarly, by assuming that the widths of the gaps correspond to 4–8× the Hill radii of forming planets (as suggested by numerical simulations), we estimate planet masses in the range of 0.2{--}1.5 {M}{Jup}, 1.0{--}8.0 {M}{Jup}, and 0.02{--}0.15 {M}{Jup} for the inner, middle, and outer gap, respectively. Given the surface density profile of the disk, the amount of “missing mass” at the location of each one of these gaps (between 4 and 20 {M}{Jup}) is more than sufficient to account for the formation of such planets.

How do Watershed Characteristics and Precipitation Influence Post-Wildfire Valley Sediment Storage and Delivery Over Time?

NASA Astrophysics Data System (ADS)

Brogan, D. J.; Nelson, P. A.; MacDonald, L. H.

2016-12-01

Considerable advances have been made in understanding post-wildfire runoff, erosion, and mass wasting at the hillslope and small watershed scale, but the larger-scale effects on flooding, water quality, and sedimentation are often the most significant impacts. The problem is that we have virtually no watershed-specific tools to quantify the proportion of eroded sediment that is stored or delivered from watersheds larger than about 2-5 km2. In this study we are quantifying how channel and valley bottom characteristics affect post-wildfire sediment storage and delivery. Our research is based on intensive monitoring of sediment storage over time in two 15 km2 watersheds (Skin Gulch and Hill Gulch) burned in the 2012 High Park Fire using repeated cross section and longitudinal surveys from fall 2012 through summer 2016, five airborne laser scanning (ALS) datasets from fall 2012 through summer 2015, and both radar and ground-based precipitation measurements. We have computed changes in sediment storage by differencing successive cross sections, and computed spatially explicit changes in successive ALS point clouds using the multiscale model to model cloud comparison (M3C2) algorithm. These channel changes are being related to potential morphometric controls, including valley width, valley slope, confinement, contributing area, valley expansion or contraction, topographic curvature (planform and profile), and estimated sediment inputs. We hypothesize that maximum rainfall intensity and lateral confinement will be the primary independent variables that describe observed patterns of erosion and deposition, and that the results can help predict post-wildfire sediment delivery and identify high priority areas for restoration.

Martian 'Swiss Cheese'

NASA Technical Reports Server (NTRS)

2000-01-01

This image is illuminated by sunlight from the upper left.

Looking like pieces of sliced and broken swiss cheese, the upper layer of the martian south polar residual cap has been eroded, leaving flat-topped mesas into which are set circular depressions such as those shown here. The circular features are depressions, not hills. The largest mesas here stand about 4 meters (13 feet) high and may be composed of frozen carbon dioxide and/or water. Nothing like this has ever been seen anywhere on Mars except within the south polar cap, leading to some speculation that these landforms may have something to do with the carbon dioxide thought to be frozen in the south polar region. On Earth, we know frozen carbon dioxide as 'dry ice'. On Mars, as this picture might be suggesting, there may be entire landforms larger than a small town and taller than 2 to 3 men and women that consist, in part, of dry ice.

No one knows for certain whether frozen carbon dioxide has played a role in the creation of the 'swiss cheese' and other bizarre landforms seen in this picture. The picture covers an area 3 x 9 kilometers (1.9 x 5.6 miles) near 85.6oS, 74.4oW at a resolution of 7.3 meters (24 feet) per pixel. This picture was taken by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) during early southern spring on August 3, 1999.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Rare Plants and Animals of the Texas Hill Country: Educator's Guide.

ERIC Educational Resources Information Center

Texas State Dept. of Parks and Wildlife, Austin.

Texas Hill Country is a land of fresh water springs, stony hills, and steep canyons and home to many rare plants and animals. Six activities for grades 3-5 and six activities for grades 6-12 are contained in this guide. Elementary activity highlights include using "The Lorax" by Dr. Seuss to stimulate critical thinking about…

Indian Hills Community College Vocational Outreach Program: Business/Industry and Indian Hills...Partners in Progress.

ERIC Educational Resources Information Center

Poort, Stephen M.; Williamson, Tom

Structured interviews were conducted by selected vocational education instructors at Indian Hills Community College (IHCC) to determine current and projected employment and training needs of private-sector businesses with 200 employees or less and to assess opinions of IHCC programs. Employers were asked to provide information on the number of…

The "House" in Half Hollow Hills

ERIC Educational Resources Information Center

Karnilow, Sheldon

2006-01-01

In this article, the author relates how he initiated a systemic improvement to Half Hollow Hills school district when he became its superintendent. He relates that although he came to Half Hollow Hills with a deep understanding of the models of systemic change, he did not bring with him a specific prescriptive plan for improvement. His plan for…

Development and Validation of a Tool for Measurement of Patient Satisfaction with Nursing Care at Oak Hill Hospital.

ERIC Educational Resources Information Center

Callow, Elizabeth K.

The Department of Nursing at Oak Hill Hospital, Spring Hill (Florida) did not have a measurement instrument for patient evaluation of hospital nursing services. An instrument to measure patient satisfaction with nursing was developed and validated. Criteria identified through a literature search were reviewed, modified, and validated by a…

27 CFR 9.49 - Central Delaware Valley.

Code of Federal Regulations, 2014 CFR

2014-04-01

... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...

27 CFR 9.49 - Central Delaware Valley.

Code of Federal Regulations, 2013 CFR

2013-04-01

... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...

27 CFR 9.49 - Central Delaware Valley.

Code of Federal Regulations, 2012 CFR

2012-04-01

... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...

27 CFR 9.49 - Central Delaware Valley.

Code of Federal Regulations, 2011 CFR

2011-04-01

... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...

Colleges as Shining Cities on a Hill

ERIC Educational Resources Information Center

Townsend, Kathleen Kennedy

2012-01-01

In this article, the author proposes that the notion of America be reintroduced as the "shining city on a hill," that abiding image from American history. The image of the shining city on a hill captures the imagination because it reflects the abiding truth that people become fully human in society, not outside of it. People need one…

AmeriFlux US-SdH Nebraska SandHills Dry Valley

DOE Data Explorer

Arkebauer, Tim J. [University of Nebraska; Billesbach, Dave [University of Nebraska

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-SdH Nebraska SandHills Dry Valley. Site Description - The Nebraska SandHills Dry Valley tower is located on public land owned by the University of Nebraska-Lincoln. The site is on a research cattle ranch where grazing primarily takes place.

Species-area relations of song birds in the Black Hills, South Dakota

Treesearch

Mark A. Rumble; Brian L. Dykstra; Lester D. Flake

2000-01-01

We investigated the effects of stand size resulting from current logging practices on occurrence and species richness of song birds in the Black Hills. Richness of forest interior and forest interior/edge songbirds was not related to stand area (P > 0.40) in stands of ponderosa pine (Pinus ponderosa) in the Black Hills. Brown creepers (...

77 FR 36599 - Self-Regulatory Organizations; NYSE Arca, Inc.; Notice of Filing and Immediate Effectiveness of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-19

... Change Relating to the Accuvest Global Long Short ETF (Formerly the Mars Hill Global Relative Value ETF...) applicable to, the Accuvest Global Long Short ETF (``Fund'') (formerly known as the Mars Hill Global Relative... the Exchange of shares (``Shares'') of the Mars Hill Global Relative Value ETF, a series of Advisor...

Conservation assessment for bloodroot in the Black Hills National Forest, South Dakota and Wyoming

Treesearch

J. Hope Hornbeck; Carolyn Hull Sieg; Deanna J. Reyher

2003-01-01

Bloodroot, Sanguinaria canadensis L. (Papaveraceae), is a common spring flowering herb in the deciduous forests of eastern North America. It is disjunctly distributed in the northeastern Black Hills of South Dakota. There are 22 known occurrences of bloodroot on Black Hills National Forest in hardwood forests, shrub thickets, and floodplain habitats of limited...

76 FR 58292 - Announcement of Funding Awards for Fiscal Year 2011; Doctoral Dissertation Research Grant Program

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-20

... Harvard University, Ms. Kathryn Edin, President and Fellows of Harvard University, 1350 Massachusetts...: $25,000 to Tanja Kubas- Meyer. 9. University of North Carolina at Chapel Hill, Mr. William Rohe, University of North Carolina at Chapel Hill, 104 Airport Drive, Ste. 2200 CB 1350, Chapel Hill, NC 27599...

77 FR 9912 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-21

....m. ET 3/2/12. Docket Numbers: ER12-743-001. Applicants: Black Hills Power, Inc. Description: GDEMA.... Comments Due: 5 p.m. ET 3/2/12. Docket Numbers: ER12-748-001. Applicants: Black Hills Power, Inc...: 20120210-5178. Comments Due: 5 p.m. ET 3/2/12. Docket Numbers: ER12-750-001. Applicants: Black Hills Power...

Accounting for imperfect detection in Hill numbers for biodiversity studies

USGS Publications Warehouse

Broms, Kristin M.; Hooten, Mevin B.; Fitzpatrick, Ryan M.

2015-01-01

The occupancy-based Hill number estimators are always at their asymptotic values (i.e. as if an infinite number of samples have been taken for the study region), therefore making it easy to compare biodiversity between different assemblages. In addition, the Hill numbers are computed as derived quantities within a Bayesian hierarchical model, allowing for straightforward inference.

Microhabitats of Merriam's turkeys in the Black Hills, South Dakota

Treesearch

Mark A. Rumble; Stanley H. Anderson

1996-01-01

Merriam’s Turkeys (Meleagris gallopavo merriami) are associated with ponderosa pine (Pinus ponderosa) forests in the western United States, but are not native to the ponderosa pine forest of the Black Hills, South Dakota. The Black Hills population was established by transplanting birds from New Mexico and Colorado between 1948 and...

75 FR 20774 - Establishment of Class E Airspace; Fort A.P. Hill, VA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-21

...-0739; Airspace Docket No. 09-AEA-14] Establishment of Class E Airspace; Fort A.P. Hill, VA AGENCY... December 7, 2009 that establishes Class E airspace at Fort A.P. Hill, VA. DATES: Effective Date: 0901 UTC... Service Center, Federal Aviation Administration, P.O. Box 20636, Atlanta, Georgia 30320; telephone (404...

78 FR 17714 - Notice of Availability of the HiLine District Draft Resource Management Plan and Draft...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-22

... (1988) and Sweet Grass Hills Amendment (1996) and Judith-Valley-Phillips Resource Management Plans (1994..., Kevin Rim, Mountain Plover, Prairie Dog Towns within the 7km Complex, and Sweet Grass Hills; these ACEC... Restrictions: Avoidance area for rights-of-way. Sweet Grass Hills ACEC (7,419 Acres) Relevant and Important...

75 FR 67997 - Notice of Correction to Notice of Intent To Prepare an Environmental Impact Statement for the Gas...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-04

... Hills Uranium Project, Fremont and Natrona Counties, WY AGENCY: Bureau of Land Management, Interior... Notice of Intent to Prepare an Environmental Impact Statement for the Gas Hills Uranium Project, Fremont... land description. The correct legal land description for the Gas Hills Uranium Project location is as...

27 CFR 9.49 - Central Delaware Valley.

Code of Federal Regulations, 2010 CFR

2010-04-01

... starting point of the following boundary description is the summit of Strawberry Hill, which is located in.... (2) Boundary Description: (i) From the summit of Strawberry Hill (475 feet) in a straight line to the... summit of Strawberry Hill (475 feet). [T.D. ATF-168, 49 FR 10117, Mar. 19, 1984, as amended by T.D. ATF...

Management Decisions and the "Dred" Hills

Treesearch

Steven W. Anderson

1992-01-01

An area of public land called the Red Hills was being so abused by the public that it was often called the "Dred" Hills. Some staff work had been accomplished to protect sensitive areas within the 7,200-acre site, but depreciative behavior continued. Primary destructive activities included off-road vehicle use and indiscriminate shooting and dumping. This...

Multiple-scale roost habitat comparisons of female Merriam's wild turkeys in the southern Black Hills, South Dakota

Treesearch

Daniel J. Thompson; Mark A. Rumble; Lester D. Flake; Chad P. Lehman

2009-01-01

Because quantity and quality of roosting habitat can affect Merriam's Wild Turkey (Meleagris gallopavo merriami) distribution, we described habitat characteristics of Merriam's turkey roost sites in the southern Black Hills of South Dakota. Varying proportions of Merriam's turkeys in the southern Black Hills depended on supplemental feed from livestock...

Silviculture of ponderosa pine in the Black Hills: The status of our knowledge

Treesearch

Charles E. Boldt; James L. Van Deusen

1974-01-01

This Paper, intended as a guide for professional foresters, describes major silvicultural conditions likely to be encountered in the Black Hills, reasonable treatment options, and probable results and implications of these treatments. It also describes silvical characteristics and behavior of Black Hills ponderosa pine, and a variety of proven silvicultural tools....

HILL: The High-Intensity Laser Laboratory Core Team's Reply to Questions from the NNSA Experimental Facilities Panel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albright, B J

2012-08-02

Question 1 - The type of physics regimes that HILL can access for weapons studies is quite interesting. The question that arises for the proposal team is what priority does this type of experimental data have versus data that can be obtained with NIF, and Z. How does HILL rank in priority compared to MARIE 1.0 in terms of the experimental data it will provide? We reiterate that isochoric heating experiments to be conducted with HILL are complementary to the high energy density physics experiments at NIF and Z and uniquely access states of matter that neither other facility canmore » access. It is our belief that HILL will enable several important questions, e.g., as related to mix morphology, radiation transfer from corrugated surfaces, and equations of state, to be run to ground through carefully diagnosed, 'unit-physics' experiments. Such experiments will substantially improve confidence in our computer models and provide a rigorous science basis for certification. Question 2 - A secondary question relates to the interests of LLNL and SNL in the physics that HILL can address. This should be spelled out clearly. I would like to see the other labs be part of the discussion regarding how important this capability would be if built. Both sister Labs have a keen interest in the physics enabled by high-intensity, high-energy lasers, as evinced by the Z Petawatt and NIF ARC upgrades to their signature facilities. LANL scientists have teamed with scientists from both Laboratories in high-intensity laser 'first experiments' envisioned for HILL and we fully intend to continue these profitable discussions going forward. In the preparation of the HILL proposal, feedback was solicited from the broader HEDP and weapons science communities. The consensus view was that HILL filled a critical gap and that there was a need for a facility like HILL to address outstanding questions in weapons science. It was recognized that co-location of HILL with a facility such as MaRIE 1.0, Z, NIF, or Omega may offer additional advantages and we would expect these to be explored and evaluated during the CD process. Question 3 - A laser/optics experts group should review this proposal to ensure the level of R&D is reasonable to provide a sufficient chance of success (>50%). In the preparation of the HILL proposal, we sent our proposal and cost estimates to laser designers/scientists across the complex. Though risks were identified with our design, the prevailing view of those we engaged was that the risks were appropriately represented by the TRL levels assigned and that the enabling R&D planned in our proposal was adequate for risk mitigation. Question 4 - More data and peer review is needed from its sister facilities around the world. It is our specific intent to conduct both scientific and technical workshops with the user community if the High Intensity Science field is further encouraged as part of the NNSA Roadmap. Question 5 - Does HILL have to be co-located with MARIE 1.0? Is that feasible from the point of view of TA-53 real estate? Multiple siting options were considered for HILL, including co-location with MaRIE 1.0 (the most cost-effective and flexible option), as well as in a separate, stand-alone building and in a retro-fitted existing building. The cost estimate included these contingencies and candidate locations for HILL in TA-53 were identified. There is actually significant space at TA-53 on the hill in the northeast end of the mesa. Question 6 - What would be the impact on the weapons program if this facility were NOT built? An inability to elucidate aspects of weapons science in the dense plasma regime and validate computer models for same. This will lead to reduced confidence in the computer tools used for certification. Question 7 - Will HILL allow some of the x-ray vulnerability studies proposed by SPARC? If so what does Sandia's vulnerability group think of this method versus SPARC. It is possible that some of the scope envisioned for SPARC could be achieved on HILL, although likely that the energy produced at HILL not being at all close to requirements. We would welcome these discussions with our SNL colleagues. Question 8 - The committee had the opinion that present laser facilities could better be modified to meet this mission need. HILL satisfies a mission need for rapid isochoric heating of materials into conditions relevant to boost with quantitative control of the variables. This is accomplished through particle generation and acceleration mechanisms that require ultra-short (sub-100 femtosecond, we estimate actually sub-30 femtosecond) laser pulses. To generate such very short pulses, high bandwidth is required in the laser system. However, such bandwidth is not possible with current high-energy glass laser systems, so new lasers must be built to meet this requirement.« less

George William Hill, the Great but Unknown 19th Century Celestial Mechanician

NASA Astrophysics Data System (ADS)

Corbin, Brenda G.

2012-01-01

George William Hill (1838-1914) has long been considered one of the most famous and talented celestial mechanicians of the past century and a half. However, many people have never heard of him and his work. Simon Newcomb said he "will easily rank as the greatest master of mathematical astronomy during the last quarter of the nineteenth century.” After receiving a B.A. at Rutgers in 1859, Hill began work in 1861 at the office of the American Ephemeris and Nautical Almanac in Cambridge, MA. He moved to Washington with the group in 1882 which then became part of the U. S. Naval Observatory. Newcomb, beginning his work on planetary motion, assigned the theory of Jupiter and Saturn to him, calling it about the most difficult topic. Hill's work was published by the USNO in 1890 as A New Theory of Jupiter and Saturn. From 1898 to 1901, Hill lectured on the subject of celestial mechanics at Columbia University in a position created just for him. After 1892 and until his death, he lived at the family homestead in West Nyack, NY. He never married, was something of a recluse, and spent most of his time with his books and research. Hill was an amateur botanist and enjoyed exploring on long walks in the countryside. Many honors and awards came to him during his lifetime, both from the U.S. and abroad, including serving as president of the American Mathematical Society. All of Hill's mathematical and astronomical research was incorporated in The Collected Mathematical Works of George William Hill. This work, containing a preface in French by Poincare, was published in 4 large volumes by the Carnegie Institution of Washington in 1905.

Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating

USGS Publications Warehouse

Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark E.; Cooper, Kari M.; Herzig, Charles; Schriener Jr., Alexander

2015-01-01

In the Salton Trough, CA, five rhyolite domes form the Salton Buttes: Mullet Island, Obsidian Butte, Rock Hill, North and South Red Hill, from oldest to youngest. Results presented here include 40Ar/39Ar anorthoclase ages, 238U-230Th zircon crystallization ages, and comparison of remanent paleomagnetic directions with the secular variation curve, which indicate that all domes are Holocene. 238U-230Th zircon crystallization ages are more precise than but within uncertainty of 40Ar/39Ar anorthoclase ages, suggesting that zircon crystallization proceeded until shortly before eruption in all cases except one. Remanent paleomagnetic directions require three eruption periods: (1) Mullet Island, (2) Obsidian Butte, and (3) Rock Hill, North Red Hill, and South Red Hill. Borehole cuttings logs document up to two shallow tephra layers. North and South Red Hills likely erupted within 100 years of each other, with a combined 238U-230Th zircon isochron age of: 2.83 ± 0.60 ka (2 sigma); paleomagnetic evidence suggests this age predates eruption by hundreds of years (1800 cal BP). Rock Hill erupted closely in time to these eruptions. The Obsidian Butte 238U-230Th isochron age (2.86 ± 0.96 ka) is nearly identical to the combined Red Hill age, but its Virtual Geomagnetic Pole position suggests a slightly older age. The age of aphyric Mullet Island dome is the least well constrained: zircon crystals are resorbed and the paleomagnetic direction is most distinct; possible Mullet Island ages include ca. 2300, 5900, 6900, and 7700 cal BP. Our results constrain the duration of Salton Buttes volcanism to between ca. 5900 and 500 years.

Neogene Fault and Feeder Dike Patterns in the Western Ross Sea

NASA Astrophysics Data System (ADS)

Magee, W. R.; Wilson, T. J.

2010-12-01

In Antarctica, where much of the continent is covered by water and ice, geophysical data from the Antarctic submarine continental shelf is a fundamental part of reconstructing geological history. Multibeam sonar from the western Ross Sea has revealed elongate volcanic edifices and fields of elongate submarine hills on the seafloor. Origin of the submarine hills as carbonate mounds and drumlins have been proposed. The hills are up to ~8000m long and ~3500m wide, and rise 50-100m above the seafloor. Morphometric analysis of the hills shows they are elongate, with axial ratios ranging from 1.2:1 to 2:1, and some hills are linked to form elongate ridges. Seismic profiles show significant pull-ups directly below the hills, consistent with narrow, higher-density magmatic bodies; thus we favor an origin as volcanic seamounts above subsurface feeder dikes. If this volcanic hypothesis is correct, feeder dikes below the hills and elongate volcanic ridges may document magmatically-forced extension within the Terror Rift. The seamount field forms part of a regional en echelon array of volcanic ridges extending NNW from Beaufort Island toward Drygalski Ice Tongue. The ridges and elongate seamount cluster trend NNE, subparallel to mapped fault trends in this sector of the Terror Rift. This geometry is compatible with right-lateral transtension along this zone, as previously proposed for the Terror Rift as a whole. Volcanic islands and dredged volcanic ridges within the en echelon array are dated at ~7-4 Ma, implying Neogene deformation. We are completing a detailed analysis of orientation patterns and cross-cutting relations between faults and volcanic hills and their feeder systems to test this model for Neogene rift kinematics.

Spirit's Course

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1Figure 2

This digital elevation map shows the topography of the 'Columbia Hills,' just in front of the Mars Exploration Rover Spirit's current position. Rover planners have plotted the safest route for Spirit to climb to the front hill, called 'West Spur.' The black line in the middle of the image represents the rover's traverse path, which starts at 'Hank's Hollow' and ends at the top of 'West Spur.' Scientists are sending Spirit up the hill to investigate the interesting rock outcrops visible in images taken by the rover. Data from the Mars Orbital Camera on the orbiting Mars Global Surveyor were used to create this 3-D map.

In figure 1, the digital map shows the slopes of the 'Columbia Hills,' just in front of the Mars Exploration Rover Spirit's current position. Colors indicate the slopes of the hills, with red areas being the gentlest and blue the steepest. Rover planners have plotted the safest route for Spirit to climb the front hill, called 'West Spur.' The path is indicated here with a curved black line. Stereo images from the Mars Orbital Camera on the orbiting Mars Global Surveyor were used to create this 3-D map.

In figure 2, the map shows the north-facing slopes of the 'Columbia Hills,' just in front of the Mars Exploration Rover Spirit's current position. Bright areas indicate surfaces sloping more toward the north than dark areas. To reach the rock outcrop at the top of the hill, engineers will aim to drive the rover around the dark areas, which would yield less solar power. The curved black line in the middle represents the rover's planned traverse path.

Step-by-Step Technique for Segmental Reconstruction of Reverse Hill-Sachs Lesions Using Homologous Osteochondral Allograft.

PubMed

Alkaduhimi, Hassanin; van den Bekerom, Michel P J; van Deurzen, Derek F P

2017-06-01

Posterior shoulder dislocations are accompanied by high forces and can result in an anteromedial humeral head impression fracture called a reverse Hill-Sachs lesion. This reverse Hill-Sachs lesion can result in serious complications including posttraumatic osteoarthritis, posterior dislocations, osteonecrosis, persistent joint stiffness, and loss of shoulder function. Treatment is challenging and depends on the amount of bone loss. Several techniques have been reported to describe the surgical treatment of lesions larger than 20%. However, there is still limited evidence with regard to the optimal procedure. Favorable results have been reported by performing segmental reconstruction of the reverse Hill-Sachs lesion with bone allograft. Although the procedure of segmental reconstruction has been used in several studies, its technique has not yet been well described in detail. In this report we propose a step-by-step description of the technique how to perform a segmental reconstruction of a reverse Hill-Sachs defect.

Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.;