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1

Asian Dust Weather Categorization with Satellite and Surface Observations  

NASA Technical Reports Server (NTRS)

This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved aerosol optical properties and surface visibility, the intensity of dust weather can be more effectively and consistently discerned using satellite rather than surface observations. In this article, datasets consisting of collocated products from Moderate Resolution Imaging Spectroradiometer Aqua and surface measurements are analysed. The results indicate an exponential relationship between the surface visibility and the satellite-retrieved aerosol optical depth, which is subsequently used to categorize the dust weather. The satellite-derived spatial frequency distributions in the dust weather types are consistent with China s weather station reports during 2003, indicating that dust weather classification using satellite data is highly feasible. Although the period during the springtime from 2004 to 2007 may be not sufficient for statistical significance, our results reveal an increasing tendency in both intensity and frequency of dust weather over central Asia during this time period.

Lin, Tang-Huang; Hsu, N. Christina; Tsay, Si-Chee; Huang, Shih-Jen

2011-01-01

2

Weather Observations  

NSDL National Science Digital Library

We will be observing the weather in our enviornment. Post your observations. Take a hike! Tell us what you see! Make sure and note the date/time/season. Take a walk in your neighboorhood- what signs show you the current season? Vacation? Make observations about the place you visited. Make obseravtions every week! Keep a journal about the changes you observe! Winter Storm ImageSeasonal ChangesAround the WorldSeasonsSeasons of the Year ...

sarahnp

2011-07-18

3

Evaluation of Two Ultrasonic Snow Depth Sensors for National Weather Service Automated Surface Observation System Sites  

Microsoft Academic Search

In the late 1980's the National Weather Service (NWS) deployed the Automated Surface Observing System (ASOS) at airport observing sites, eliminating the need for human observers. At the time there were no reliable sensors to measure snow depth and the traditional snow measurements of 6 hour snowfall and snow water equivalent (SWE) were abandoned at most locations. The National Weather

W. A. Brazenec; N. J. Doesken; S. R. Fassnacht

2004-01-01

4

AFB, Wa. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts a-f. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for McChord AFB, WA. It contains the following parts: (a) Weather Conditions; Atmospheric Phenomena; (b) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (c) Surface winds; (d) Ceiling versus Visibility; Sky Cover; (e) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew point temperatures and relative humidity); and (f) Pressure Summary (means, standard deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-06-20

5

Weather Observing Fundamentals  

NSDL National Science Digital Library

"Weather Observing Fundamentals" provides guidance for U.S. Navy Aerographer's Mates, Quartermasters, and civilian observers tasked with taking and reporting routine, special, and synoptic observations. Although the focus of this lesson is on shipboard observations, much of the content applies to land-based observing and reporting as well. The lesson details standard procedures for taking accurate weather observations and for encoding those observations on COMNAVMETOCCOM Report 3141/3. Exercises throughout the lesson and four weather identification drills at the end provide learners with opportunities to practice and build their skills. The lesson covers a large amount of content. You may wish to work through the material in multiple sessions.

2014-09-14

6

Evaluation of Two Ultrasonic Snow Depth Sensors for National Weather Service Automated Surface Observation System Sites  

NASA Astrophysics Data System (ADS)

In the late 1980's the National Weather Service (NWS) deployed the Automated Surface Observing System (ASOS) at airport observing sites, eliminating the need for human observers. At the time there were no reliable sensors to measure snow depth and the traditional snow measurements of 6 hour snowfall and snow water equivalent (SWE) were abandoned at most locations. The National Weather Service is currently exploring the feasibility of installing ultrasonic snow depth sensors at ASOS sites to restore snowfall measurements to the historic data record. In the 2003-2004 snow season testing of the Judd Communications ultrasonic depth sensor began at three sites: Fort Collins, CO; Stove Prairie, CO; and New Brunswick, OH. Preliminary results show that due to scattering of the sound pulse the Judd sensor performs poorly under windy conditions and when low density snow is present on the snow surface. In addition to the automated data, 6 and 24 hour manual measurements of snowfall, snow depth, snow water equivalent and gauge precipitation were collected. For the 2004-2005 snow season, 15 sites across the U.S. will test both the Judd Communications and the Campbell Scientific sensors. This poster will show three aspects of the project: i) the magnitude and characteristics of noise in the sensor data, ii) an algorithm to convert continuous sensor total snow depth data to the traditional NWS 6 hour snowfall measurements, and iii) a comparison of the performance of the two sensors.

Brazenec, W. A.; Doesken, N. J.; Fassnacht, S. R.

2004-12-01

7

Optimizing weather radar observations using an adaptive multiquadric surface fitting algorithm  

NASA Astrophysics Data System (ADS)

Real time forecasting of river flow is an essential tool in operational water management. Such real time modelling systems require well calibrated models which can make use of spatially distributed rainfall observations. Weather radars provide spatial data, however, since radar measurements are sensitive to a large range of error sources, often a discrepancy between radar observations and ground-based measurements, which are mostly considered as ground truth, can be observed. Through merging ground observations with the radar product, often referred to as data merging, one may force the radar observations to better correspond to the ground-based measurements, without losing the spatial information. In this paper, radar images and ground-based measurements of rainfall are merged based on interpolated gauge-adjustment factors (Moore et al., 1998; Cole and Moore, 2008) or scaling factors. Using the following equation, scaling factors (C(x?)) are calculated at each position x? where a gauge measurement (Ig(x?)) is available: Ig(x?)+-? C (x?) = Ir(x?)+ ? (1) where Ir(x?) is the radar-based observation in the pixel overlapping the rain gauge and ? is a constant making sure the scaling factor can be calculated when Ir(x?) is zero. These scaling factors are interpolated on the radar grid, resulting in a unique scaling factor for each pixel. Multiquadric surface fitting is used as an interpolation algorithm (Hardy, 1971): C*(x0) = aTv + a0 (2) where C*(x0) is the prediction at location x0, the vector a (Nx1, with N the number of ground-based measurements used) and the constant a0 parameters describing the surface and v an Nx1 vector containing the (Euclidian) distance between each point x? used in the interpolation and the point x0. The parameters describing the surface are derived by forcing the surface to be an exact interpolator and impose that the sum of the parameters in a should be zero. However, often, the surface is allowed to pass near the observations (i.e. the observed scaling factors C(x?)) on a distance a?K by introducing an offset parameter K, which results in slightly different equations to calculate a and a0. The described technique is currently being used by the Flemish Environmental Agency in an online forecasting system of river discharges within Flanders (Belgium). However, rescaling the radar data using the described algorithm is not always giving rise to an improved weather radar product. Probably one of the main reasons is the parameters K and ? which are implemented as constants. It can be expected that, among others, depending on the characteristics of the rainfall, different values for the parameters should be used. Adaptation of the parameter values is achieved by an online calibration of K and ? at each time step (every 15 minutes), using validated rain gauge measurements as ground truth. Results demonstrate that rescaling radar images using optimized values for K and ? at each time step lead to a significant improvement of the rainfall estimation, which in turn will result in higher quality discharge predictions. Moreover, it is shown that calibrated values for K and ? can be obtained in near-real time. References Cole, S. J., and Moore, R. J. (2008). Hydrological modelling using raingauge- and radar-based estimators of areal rainfall. Journal of Hydrology, 358(3-4), 159-181. Hardy, R.L., (1971) Multiquadric equations of topography and other irregular surfaces, Journal of Geophysical Research, 76(8): 1905-1915. Moore, R. J., Watson, B. C., Jones, D. A. and Black, K. B. (1989). London weather radar local calibration study. Technical report, Institute of Hydrology.

Martens, Brecht; Cabus, Pieter; De Jongh, Inge; Verhoest, Niko

2013-04-01

8

Subgrid Surface Fluxes in Fair Weather Conditions during TOGA COARE: Observational Estimates and Parameterization  

Microsoft Academic Search

Bulk aerodynamic formulas are applied to meteorological data from low-altitude aircraft flights to obtain observational estimates of the subgrid enhancement of momentum, sensible heat, and latent heat exchange at the atmospheric-oceanic boundary in light wind, fair weather conditions during TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment). Here, subgrid enhancement refers to the contributions of unresolved disturbances to

Dean Vickers; Steven K. Esbensen

1998-01-01

9

Loring AFB, Caribou, Maine. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts a-f. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Loring AFB, Caribou, ME. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew point temperatures and relative humidity); and (F) Pressure Summary (means, standard deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables. (Author)

Not Available

1980-06-27

10

Kingsley Field, Klamath Falls, Oregon. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts a-f. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Kingsley Field, Klamath Falls, OR. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew point temperatures and relative humidity); and (F) Pressure Summary (means, standard deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-07-16

11

F. E. Warren AFB, Cheyenne, Wyoming. Revised uniform summary of surface weather observations (RUSSWO). Parts A-F. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for F E Warren AFB, Cheyenne, Wyoming. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-05-01

12

Monterey FAA, Monterey, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts a, c-f. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Monterey FAA, Monterey, CA. It contains the following parts: (a) Weather Conditions; Atmospheric Phenomena; (b) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (c) Surface winds; (d) Ceiling versus Visibility; Sky Cover; (e) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew point temperatures and relative humidity); and (f) Pressure Summary (means, standard deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-07-24

13

Charleston AFB, Charleston, South Carolina. Revised uniform summary of surface weather observations (RUSSWO). Parts A-F. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Charleston AFB, Charleston, South Carolina. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-04-23

14

Misawa AB, Japan. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts a-e. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Misawa AB, JP. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew point temperatures and relative humidity); and (F) Pressure Summary (means, standard deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-07-03

15

Weather induced effects on extensive air showers observed with the surface detector of the Pierre Auger Observatory  

E-print Network

The rate of events measured with the surface detector of the Pierre Auger Observatory is found to be modulated by the weather conditions. This effect is due to the increasing amount of matter traversed by the shower as the ground pressure increases and to the inverse proportionality of the Moliere radius to the air density near ground. Air-shower simulations with different realistic profiles of the atmosphere support this interpretation of the observed effects.

Carla Bleve; for the Pierre Auger Collaboration

2007-06-11

16

Surface Pressure Observations from Smartphones:3 A Potential Revolution for High-Resolution Weather Prediction?4  

E-print Network

1 1 2 Surface Pressure Observations from Smartphones:3 A Potential Revolution for High Revised November 201313 14 Capsule Description: Pressure observations from smartphones have the potential of smartphones now possess relatively accurate pressure sensors and the18 expectation is that these numbers

Mass, Clifford F.

17

Toward the Assimilation of the Atmospheric Surface Layer Using Numerical Weather Prediction and Radar Clutter Observations  

E-print Network

and Radar Clutter Observations ALI KARIMIAN AND CAGLAR YARDIM Scripps Institution of Oceanography referred to as an evaporation duct (ED). Refractivity from clutter (RFC) is an inversion approach for the estimation of the refractivity profile from radar clutter, and RFC-ED refers to its implementation

Gerstoft, Peter

18

Richards-Gebaur AFB, Kansas City, Missouri. Revised uniform summary of surface weather observations (RUSSWO). Parts A-F. Final report  

SciTech Connect

This report is a six-part statistical summary of surface weather observations for Richards-Gebaur AFB, Kansas City, Missouri. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

Not Available

1980-03-31

19

SPACE WEATHER OBSERVING SYSTEMS: CURRENT CAPABILITIES AND  

E-print Network

- REPORT ON SPACE WEATHER OBSERVING SYSTEMS: CURRENT CAPABILITIES AND REQUIREMENTS FOR THE NEXT and Supporting Research National Space Weather Program Council Joint Action Group for Space Environmental Gap of the President #12;ii NATIONAL SPACE WEATHER PROGRAM COUNCIL (NSWPC) MR. SAMUEL P. WILLIAMSON, Chairman Federal

Schrijver, Karel

20

Cloud information for FIRE from surface weather reports  

NASA Technical Reports Server (NTRS)

Surface weather observations of clouds were analyzed to obtain a global cloud climatology (Warren et al, 1986; 1988). The form of the synoptic weather code limits the types of cloud information which are available from these reports. Comparison of surface weather reports with instrumental observations during the FIRE field experiments can help to clarify the operational definitions which were made in the climatology because of the nature of the synoptic code. The long-term climatology from surface weather observations is also useful background for planning the location and timing of intensive field experiments.

Hahn, Carole J.; Warren, Stephen G.; London, Julius

1990-01-01

21

Earth Observation Services Weather Imaging  

NASA Technical Reports Server (NTRS)

Microprocessor-based systems for processing satellite data offer mariners real-time images of weather systems, day and night, of large areas or allow them to zoom in on a few square miles. Systems West markets these commercial image processing systems, which have significantly decreased the cost of satellite weather stations. The company was assisted by the EOCAP program, which provides government co-funding to encourage private investment in, and to broaden the use of, NASA-developed technology for analyzing information about Earth and ocean resources.

1992-01-01

22

Statistics of link blockage due to cloud cover for free-space optical communications using NCDC surface weather observation data  

Microsoft Academic Search

Cloud opacity is one of the main atmospheric physical phenomena that can jeopardize the successful completion of an optical link between a spacecraft and a ground station. Hence, the site location chosen for a telescope used for optical communications must rely on knowledge of weather and cloud cover statistics for the geographical area where the telescope itself is located. In

Sabino Piazzolla; Stephen D. Slobin

2002-01-01

23

Statistics of link blockage due to cloud cover for free-space optical communications using NCDC surface weather observation data  

NASA Technical Reports Server (NTRS)

Cloud opacity is one of the main atmospheric physical phenomena that can jeopardize the successful completion of an optical link between a spacecraft and a ground station. Hence, the site location chosen for a telescope used for optical communications must rely on knowledge of weather and cloud cover statistics for the geographical area where the telescope itself is located.

Slobin, S. D.; Piazzolla, S.

2002-01-01

24

Unified Surface Analysis Manual Weather Prediction Center  

E-print Network

Unified Surface Analysis Manual Weather Prediction Center Ocean Prediction Center National: Bibliography.................................................................30 Appendix A: Unified Graphics land, and in recent decades, the Shapiro-Keyser Model over the mid-latitudes of the ocean. The graphic

25

Surface mass-balance observations and automatic weather station data along a transect near Kangerlussuaq, West Greenland  

Microsoft Academic Search

Surface mass-balance data from the Kangerlussuaq transect (K-transect) located on the western part of the Greenland ice sheet near 678 N are presented. The series covers the period 1990- 2003 and is the longest series of surface mass-balance measurements in Greenland. The surface mass- balance measurements cover an altitude range of 390-1850 m and show a linear increase of the

W. Greuell; M. R. van den Broeke; C. H. Reijmer; J. Oerlemans

2005-01-01

26

Field Observations of Weathering and Mass Wasting  

NSDL National Science Digital Library

This activity requires students to locate local examples of physical and chemical weathering, as well mass wasting, for which they must identify the type of process involved and describe the resulting effects on landform development. The students must write up their observations in a brief, written report using a technical writing style, which must include labeled photographs and sketches that support their observations and descriptions.

Davis, Lisa

27

MESSENGER Observations of Extreme Space Weather in Mercury's Magnetosphere  

NASA Astrophysics Data System (ADS)

Increasing activity on the Sun is allowing MESSENGER to make its first observations of Mercury's magnetosphere under extreme solar wind conditions. At Earth interplanetary shock waves and coronal mass ejections produce severe "space weather" in the form of large geomagnetic storms that affect telecommunications, space systems, and ground-based power grids. In the case of Mercury the primary effect of extreme space weather in on the degree to which this it's weak global magnetic field can shield the planet from the solar wind. Direct impact of the solar wind on the surface of airless bodies like Mercury results in space weathering of the regolith and the sputtering of atomic species like sodium and calcium to high altitudes where they contribute to a tenuous, but highly dynamic exosphere. MESSENGER observations indicate that during extreme interplanetary conditions the solar wind plasma gains access to the surface of Mercury through three main regions: 1. The magnetospheric cusps, which fill with energized solar wind and planetary ions; 2. The subsolar magnetopause, which is compressed and eroded by reconnection to very low altitudes where the natural gyro-motion of solar wind protons may result in their impact on the surface; 3. The magnetotail where hot plasma sheet ions rapidly convect sunward to impact the surface on the nightside of Mercury. The possible implications of these new MESSENGER observations for our ability to predict space weather at Earth and other planets will be described.

Slavin, J. A.

2013-09-01

28

Rates of oxidative weathering on the surface of Mars  

NASA Technical Reports Server (NTRS)

Implicit in the mnemonic 'MSATT' (Mars surface and atmosphere through time) is that rates of surface processes on Mars through time should be investigated, including studies of the kinetics and mechanism of oxidative weathering reactions occurring in the Martian regolith. Such measurements are described. Two major elements analyzed in the Viking Lander XRF experiment that are most vulnerable to atmospheric oxidation are iron and sulfur. Originally, they occurred as Fe(2+)-bearing silicate and sulfide minerals in basaltic rocks on the surface of Mars. However, chemical weathering reactions through time have produced ferric- and sulfate-bearing assemblages now visible in the Martian regolith. Such observations raise several question about: (1) when the oxidative weathering reactions took place on Mars; (2) whether or not the oxidized regolith is a fossilized remnant of past weathering processes; (3) deducting chemical interactions of the ancient Martian atmosphere with its surface from surviving phases; (4) possible weathering reactions still occurring in the frozen regolith; and (5) the kinetics and mechanism of past and present-day oxidative reactions on Mars. These questions may be addressed experimentally by studying reaction rates of dissolution and oxidation of basaltic minerals, and by identifying reaction products forming on the mineral surfaces. Results for the oxidation of pyrrhotite and dissolved ferrous iron are reported.

Burns, Roger G.

1992-01-01

29

Evaluating climate models: Should we use weather or climate observations?  

SciTech Connect

Calling the numerical models that we use for simulations of climate change 'climate models' is a bit of a misnomer. These 'general circulation models' (GCMs, AKA global climate models) and their cousins the 'regional climate models' (RCMs) are actually physically-based weather simulators. That is, these models simulate, either globally or locally, daily weather patterns in response to some change in forcing or boundary condition. These simulated weather patterns are then aggregated into climate statistics, very much as we aggregate observations into 'real climate statistics'. Traditionally, the output of GCMs has been evaluated using climate statistics, as opposed to their ability to simulate realistic daily weather observations. At the coarse global scale this may be a reasonable approach, however, as RCM's downscale to increasingly higher resolutions, the conjunction between weather and climate becomes more problematic. We present results from a series of present-day climate simulations using the WRF ARW for domains that cover North America, much of Latin America, and South Asia. The basic domains are at a 12 km resolution, but several inner domains at 4 km have also been simulated. These include regions of complex topography in Mexico, Colombia, Peru, and Sri Lanka, as well as a region of low topography and fairly homogeneous land surface type (the U.S. Great Plains). Model evaluations are performed using standard climate analyses (e.g., reanalyses; NCDC data) but also using time series of daily station observations. Preliminary results suggest little difference in the assessment of long-term mean quantities, but the variability on seasonal and interannual timescales is better described. Furthermore, the value-added by using daily weather observations as an evaluation tool increases with the model resolution.

Oglesby, Robert J [ORNL; Erickson III, David J [ORNL

2009-12-01

30

Widespread Surface Weathering on Early Mars  

NASA Astrophysics Data System (ADS)

The recent discovery of widespread hydrous clays on Mars indicates that diverse and widespread aqueous environments existed on Mars, from the surface to kilometric depths [1,2]. The study of the past habitability of the planet requires assessing the importance of sustained surface water vs. subsurface water in its aqueous history. Using remote sensing data, we propose that surface weathering existed on Mars, suggesting that Mars experienced durable episodes of sustained liquid water on its surface. Weathering profiles are identified as vertical sequences of Al-rich clays and Fe/Mg-rich clays in the top tens of meters of the surface, similar to cases of pedogenesis on Earth (e.g. [3,4]). Such localized clay sequences have been reported by other works in 3 regions of Mars [5-8] and a similar origin was also proposed. Their frequency is however likely underestimated due to limitations of orbital investigations and re-surfacing processes. A large survey of the CRISM dataset leaded to a down-selection of 104 deposits with clear vertical sequences, widely distributed over the southern highlands and grouped in regional clusters [9]. These putative weathering sequences are found either on inter-crater plateaus, on the floor of craters and large basins, or on crater ejectas. We investigated the thickness of the altered sequences, the age of the altered units and the different geological contexts to further understand the weathering process(es). Using few HiRISE DEMs where possible, and CTX DEMs, we find that the thickness of the exposed Al clays is on average of the order of several meters to few tens of meters. The clay sequences reported here are consistent with terrestrial weathering sequences which form under wet climates over geological timescales (> 105-107 years). The combined age assessment of the altered unit and the unaltered capping (where present) provides constraints on the age of the weathering itself. All investigated cases point to an active weathering limited to the late Noachian to early Hesperian. The widespread distribution of weathering sequences in different geologic contexts, and the consistency in their estimated ages are best explained if Mars experienced a period/periods between the middle Noachian and the early Hesperian during which climatic conditions allowed sustained liquid water flow on its surface, while the high degree of degradation of older terrains does not allow affirming nor infirming earlier surface weathering on Mars. Only the in-situ exploration of Phyllosian/Noachian terrains may provide an answer to this fundamental question. Some of the authors have received funding from the European Research Council (FP7/2007-2013)/ERC Grant agreement n° 280168. [1] Ehlmann B., et al. Nature, 479, 53-60 (2011). [2] Carter J., et al. JGR, 118, 831-858 (2013) [3] Velde B., et al. Ed. Springer, Berlin, (1995). [4] Wilson M. Clay Minerals, 39, 233-266 (2004). [5] Gaudin A., et al. Icarus, 216(1), 257-268 (2011). [6] Loizeau D., et al. Icarus, 205, 396-418 (2010). [7] Noe Dobrea E., et al. JGR, 115, E00D19 (2010). [8] Le Deit L., et al. JGR, 117, E00J05 (2012). [9] Carter J., et al. LPSC 2012, p.1755

Loizeau, D.; Carter, J.; Mangold, N.; Poulet, F.; Rossi, A.; Allemand, P.; Quantin, C.; Bibring, J.

2013-12-01

31

Ornithology Based on Linking Bird Observations with Weather Data  

E-print Network

Ornithology Based on Linking Bird Observations with Weather Data Mikko Koho1,2 , Eero Hyv¨onen2 results of a use case of Linked Data for eScience, where 0.5 million rows of bird migration observations over 30 years time span are linked with 0.1 million rows of related weather observations and a bird

Hyvönen, Eero

32

Surface Landing Site Weather Analysis for Constellation Program  

NASA Technical Reports Server (NTRS)

Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is an important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface atmospheric conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. Climatological time series of operational surface weather observations are used to calculate probabilities of occurrence of various sets of hypothetical vehicle constraint thresholds, Data are available for numerous geographical locations such that statistical analysis can be performed for single sites as well as multiple-site network configurations. Results provide statistical descriptions of how often certain weather conditions are observed at the site(s) and the percentage that specified criteria thresholds are matched or exceeded. Outputs are tabulated by month and hour of day to show both seasonal and diurnal variation. This paper will describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that can be obtained,

Altino, Karen M.; Burns, K. Lee

2008-01-01

33

Observe the effects of mechanical weathering  

NSDL National Science Digital Library

In this interactive Earth science resource, students are first presented with six photographs, each featuring a different mechanical weathering event in which rock is broken down. Examples of the events include road damage due to ice heaving and the expansion of cracks in rocks due to tree growth. Students are instructed to click on each labeled image to see an enlarged version of it. In the enlarged view, brief text, often accompanied by visual cues such as arrows, explains the physical weathering process shown. Copyright 2005 Eisenhower National Clearinghouse

Education, Terc. C.; Littell, Mcdougal

2003-01-01

34

GOES-R and Next Generation Weather Observation Systems  

NASA Astrophysics Data System (ADS)

The Earth Observing community is preparing for the next generation of weather and observation remote sensing systems. These systems are constellations that provide a much richer sensor suite that provides significant increases in data rates, types of data and resultant volumes. In this new era weather and observation data are made more integrated, and multiple mechanisms for accessing this data and dedicated services that leverage it will be made available. The purpose of this presentation will be to introduce this next generation of weather and observation constellations, including the GOES-R system as an example, and to provide a platform for other presentations in this session.

Krause, R. G.; Burnett, M.

2011-12-01

35

Evidence of Space Weathering Processes Across the Surface of Vesta  

NASA Technical Reports Server (NTRS)

As NASA s Dawn spacecraft explores the surface of Vesta, it has become abundantly clear that Vesta is like no other planetary body visited to date. Dawn is collecting global data at increasingly higher spatial resolution during its one-year orbital mission. The bulk properties of Vesta have previously been linked to the HED meteorites through remote mineral characterization of its surface from Earth-based spectroscopy. A principal puzzle has been why Vesta exhibits relatively unweathered diagnostic optical features compared to other large asteroids. Is this due to the composition of this proto-planet or the space environment at Vesta? Alteration or weathering of materials in space normally develops as the products of several processes accumulate on the surface or in an evolving particulate regolith, transforming the bedrock into fragmental material with properties that may be measurably different from the original. Data from Dawn reveal that the regolith of Vesta is exceptionally diverse. Regional surface units are observed that have not been erased by weathering with time. Several morphologically-fresh craters have excavated bright, mafic-rich materials and exhibit bright ray systems. Some of the larger craters have surrounding subdued regions (often asymmetric) that are lower in albedo and relatively red-sloped in the visible while exhibiting weaker mafic signatures. Several other prominent craters have rim exposures containing very dark material and/or display a system of prominent dark rays. Most, but not all, dark areas associated with craters exhibit significantly lower spectral contrast, suggesting that either a Vesta lithology with an opaque component has been exposed locally or that the surface has been contaminated by a relatively dark impactor. Similarly, most, but not all, bright areas associated with craters exhibit enhanced mafic signatures compared to surroundings. On a regional scale, the large south polar structure and surrounding terrain exhibit relatively strong mafic absorption features, suggesting either a concentration of mafic materials or that materials exposed have been less affected by space weathering products. These combined initial observations indicate some space weathering processes are active in this part of the main asteroid belt, but are highly variable across the surface of Vesta. Such processes include: impacts from wandering asteroidal debris and local mixing at both micro- and macro-scales, irradiation by solar wind and galactic particles, production and distribution of impact breccias or melt products, and local movement of materials to gravity lows (gradual as well as sudden).

Pieters, Carle M.; Blewett, David T.; Gaffey, Michael; Mittlefehldt, David W.; CristinaDeSanctis, Maria; Reddy, Vishnu; Coradini, Angioletta; Nathues, Andreas; Denevi, Brett W.; Li, Jian-Yang; McCord, Thomas B.; Marchi, Simone; Palmer, Eric E.; Sunshine, Jessica M.; Filacchione, Gianrico; Ammannito, Eleonora; Raymond, Carol A.; Russell, Christopher T.

2011-01-01

36

Rock Rinds at Meridiani and Surface Weathering Phenomena  

NASA Astrophysics Data System (ADS)

The Rock Abrasion Tool (RAT) on the Mars rover Opportunity can brush away surface dust and grind away outcrop surface, exposing presumably less altered rock at depths of several mm. Alpha particle X-ray spectrometer (APXS) and Moessbauer spectrometer (MB) analyses of pre- and post-RAT targets, thus, provide information on the chemical nature of weathering of Meridiani outcrop rocks. To date, Opportunity has analyzed some 25 undisturbed rock surfaces, brushed and then analyzed 7 more, and ground 23 targets for IDD analysis. Panoramic camera images show that outcrop surfaces are typically either buff or purple (as viewed in bands centered at 673, 535, and 432 nm, Farrand et al., JGR, in press). Relatively flat surfaces that are approximately parallel to the ground are typically buff, whereas those that slope steeply tend to be purple. Surfaces of rock interiors ground by the RAT are also commonly purple. Spectrally, these color differences correspond to more oxidized (buff) and less oxidized (purple), and appear to relate to the degree of eolian abrasion. Flat-lying surfaces are not eroded as quickly, thus surfaces chemically weathered by exposure to tenuous atmospheric vapor may be preserved. These observations are consistent with in-situ analyses of rock surfaces and interiors. Compared to interiors, rock surfaces have about 1/3 less S, and in general, surface compositions lie between those of rock interiors and average surface soil. In detail, they differ from soil-rock mixtures as follows: surfaces are relatively depleted in Mg, Fe, Mn, Ti, and Cr, and they are enriched in Al, Na, K, P, Cl, and Si. From MB analyses, surfaces are richer (compared to soil-rock mixtures) in oxidized Fe phases and poorer in magnetite, olivine, and pyroxene. Morphologically, numerous flat-lying rocks and outcrop surfaces that are at or near the ground surface have a rind of erosionally resistant material. Such rinds are also chemically distinct from outcrop interiors. A rind/subjacent rock pair analyzed in detail was "Lemon Rind" and "Strawberry," ca. sols 555-560. The rind is depleted in S (balanced mainly by increased Si and Al) and, compared to a soil-rock mixture, it is depleted in Mg, Ti, Cr, Mn, and slightly in Fe, and it is enriched in Na, Cl, K, and P. Differences between rock surfaces and interiors, and between hardened weathering rinds and rock interiors, are consistent with loss of Mg-sulfate, oxidation of mafic minerals, enrichment of siliciclastic material, e.g., feldspar, and enrichment in chloride. These changes are consistent with slow rates of chemical weathering via interaction with small amounts of atmospheric water vapor or condensation. Erosionally resistant rinds may be related to preservation of aqueous condensate by a thin cover of soil on flat, near-surface rocks.

Jolliff, B.; Knoll, A.; Farrand, W.; Sullivan, R.

2006-12-01

37

Generation of Multivariate Surface Weather Series with Use of the Stochastic Weather Generator Linked to Regional Climate Model  

NASA Astrophysics Data System (ADS)

The regional-scale simulations of weather-sensitive processes (e.g. hydrology, agriculture and forestry) for the present and/or future climate often require high resolution meteorological inputs in terms of the time series of selected surface weather characteristics (typically temperature, precipitation, solar radiation, humidity, wind) for a set of stations or on a regular grid. As even the latest Global and Regional Climate Models (GCMs and RCMs) do not provide realistic representation of statistical structure of the surface weather, the model outputs must be postprocessed (downscaled) to achieve the desired statistical structure of the weather data before being used as an input to the follow-up simulation models. One of the downscaling approaches, which is employed also here, is based on a weather generator (WG), which is calibrated using the observed weather series and then modified (in case of simulations for the future climate) according to the GCM- or RCM-based climate change scenarios. The present contribution uses the parametric daily weather generator M&Rfi to follow two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate/CZ (v.2) Regional Climate Model at 25 km resolution. The WG parameters will be derived from the RCM-simulated surface weather series and compared to those derived from observational data in the Czech meteorological stations. The set of WG parameters will include selected statistics of the surface temperature and precipitation (characteristics of the mean, variability, interdiurnal variability and extremes). (2) Testing a potential of RCM output for calibration of the WG for the ungauged locations. The methodology being examined will consist in using the WG, whose parameters are interpolated from the surrounding stations and then corrected based on a RCM-simulated spatial variability. The quality of the weather series produced by the WG calibrated in this way will be assessed in terms of selected climatic characteristics focusing on extreme precipitation and temperature characteristics (including characteristics of dry/wet/hot/cold spells). Acknowledgements: The present experiment is made within the frame of projects ALARO (project P209/11/2405 sponsored by the Czech Science Foundation), WG4VALUE (project LD12029 sponsored by the Ministry of Education, Youth and Sports) and VALUE (COST ES 1102 action).

Dubrovsky, M.; Farda, A.; Huth, R.

2012-12-01

38

Titan's seasonal weather patterns, associated surface modification, and geological implications  

NASA Astrophysics Data System (ADS)

Model predictions [e.g., 1-3] and observations [e.g., 4,5] illustrate changes in Titan's weather patterns related to the seasons (Fig. 1). In two cases, surface changes were documented following large cloud outbursts (Figs. 2, 3): the first in Arrakis Planitia at high southern latitudes in Fall 2004, during Titan's late southern summer [6]; and the second at lows southern latitudes in Concordia and Hetpet Regiones, Yalaing Terra (Fig. 3), and Adiri, in Fall 2010, just over a year after Titan's northern vernal equinox [4, 7, 8]. Not only do these storms demonstrate Titan's atmospheric conditions and processes, they also have important implications for Titan's surface process, its methane cycle, and its geologic history.

Turtle, E. P.; Perry, J. E.; Barnes, J. W.; McEwen, A. S.; Barbara, J. M.; Del Genio, A. D.; Hayes, A. G.; West, R. A.; Lorenz, R. D.; Schaller, E. L.; Lunine, J. I.; Ray, T. L.; Lopes, R. M. C.; Stofan, E. R.

2013-09-01

39

DETECTION OF A LARGE VARIATION IN THE DEGREE OF SPACE WEATHERING ON THE SURFACE OF ITOKAWA BY HAYABUSA/AMICA OBSERVATIONS. M. Ishiguro  

E-print Network

is equipped with seven narrowband filters for the scientific observations as well as a wide-band filter for the optical navigation [8]. The filter system of nar- rowband filters is nearly equivalent to that of Eight was performed using both ground-based observations of Itokawa by the ECAS filter system and AMICA data around

Hiroi, Takahiro

40

Aviation Weather Observations for Supplementary Aviation Weather Reporting Stations (SAWRS) and Limited Aviation Weather Reporting Stations (LAWRS). Federal Meteorological Handbook No. 9.  

ERIC Educational Resources Information Center

This handbook provides instructions for observing, identifying, and recording aviation weather at Limited Aviation Weather Reporting Stations (LAWRS) and Supplementary Aviation Weather Reporting Stations (SAWRS). Official technical definitions, meteorological and administrative procedures are outlined. Although this publication is intended for use…

Department of Transportation, Washington, DC.

41

Weathering  

NSDL National Science Digital Library

This course handout covers the processes and effects of weathering. The purpose of this handout is to contrast weathering and erosion, contrast and discuss chemical and mechanical weathering, list the products resulting from the chemical weathering of igneous rocks, and list and discuss the factors that influence the type and rate of rock weathering. Many photographs accompany this summary which depict weathered landscapes. Links are provided to the online Physical Geology resources at Georgia Perimeter College.

Pamela Gore

1995-08-29

42

Physical and chemical weathering. [of Martian surface and rocks  

NASA Technical Reports Server (NTRS)

Physical and chemical weathering processes that might be important on Mars are reviewed, and the limited observations, including relevant Viking results and laboratory simulations, are summarized. Physical weathering may have included rock splitting through growth of ice, salt or secondary silicate crystals in voids. Chemical weathering probably involved reactions of minerals with water, oxygen, and carbon dioxide, although predicted products vary sensitively with the abundance and physical form postulated for the water. On the basis of kinetics data for hydration of rock glass on earth, the fate of weathering-rind formation on glass-bearing Martian volcanic rocks is tentatively estimated to have been on the order of 0.1 to 4.5 cm/Gyr; lower rates would be expected for crystalline rocks.

Gooding, James L.; Arvidson, Raymond E.; Zolotov, Mikhail IU.

1992-01-01

43

Land-surface influences on weather and climate  

NASA Technical Reports Server (NTRS)

Land-surface influences on weather and climate are reviewed. The interrelationship of vegetation, evapotranspiration, atmospheric circulation, and climate is discussed. Global precipitation, soil moisture, the seasonal water cycle, heat transfer, and atmospheric temperature are among the parameters considered in the context of a general biosphere model.

Baer, F.; Mintz, Y.

1984-01-01

44

Weather  

NSDL National Science Digital Library

What are the different types of weather? In this project you will compare different types of weather by drawing pictures and making it into a flip book. First you will begin by learning about the different types of weather. Read about each topic. Then get together with your partner and draw a picture of each type of weather. 1. Thunder storm Thunder storm Thunder storm Kids 2. Lightning Lightning Lightning picture 3. Tornado Tornadoes Tornado Kids 4. ...

Jennie, Miss

2009-10-22

45

Infrared spectroscopy of weathering products in a terrestrial glacial environment: Implications for cold weathering on planetary surfaces  

NASA Astrophysics Data System (ADS)

Geologic features on Mars show evidence of modification by water and water ice. Past obliquity variations are hypothesized to have allowed the formation and stability of ground ice near the equator, possibly promoting the accumulation of glaciers. Massive ice deposits, including probable glacial and periglacial features have also been observed in the east Hellas Basin and Deuteronilus Mensae regions, located at the midlatitudes of Mars. These features indicate present-day, near-surface ice has been in contact with geologic materials, creating an environment in which cold weathering processes could have been occurring, and might still be at work. Weathering processes in cold terrestrial environments are not well understood, and processes acting on subglacial and englacial sediments and rocks are not well characterized due to the remote location of many glaciers and the difficulty of collecting samples. The types of weathering products and energy sources produced in a glacial environment will drive the overall energy budget for any microbial communities present. The subglacial energy budget for microbes thus has implications in the search for life on other planets, making glacial and periglacial terrains excellent sites for future exploration. However, planetary ice deposits are difficult to study due to their sensitive nature and are thus limited to observation from orbit at present. It is therefore a key concern to better understand the types materials and alteration products that can be observed and constrained from orbital data. In this study, we characterize the types of weathering products present in a glacial system using ground-truthed remote sensing techniques. Robertson Glacier, Alberta, Canada (115°20'W, 50°44'N) provides an excellent testbed for this technique as it is accessible, and its recent and continuing retreat allows fresh subglacial and englacial sediments to be sampled. Samples of bedrock and glacially altered rock and sediments were collected from Robertson Glacier. Infrared laboratory spectra of these samples were collected and used to determine the composition and abundance of minerals in rock and sediment samples, with a primary focus on differentiating weathering products. These spectra were then correlated to multispectral images taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite instrument. Initial results from both laboratory and ASTER data indicate the presence of weathering products. Laboratory spectra of field samples are promising in that major bedrock mineral assemblages and a variety of alteration products can be identified. However, more mineralogical work is required to refine the types of weathering products present in the system.

Rutledge, A. M.; Christensen, P. R.; Havig, J. R.

2011-12-01

46

Two cases of severe weather in Catalonia (Spain): an observational study  

Microsoft Academic Search

Surface observations, satellite and radar imagery and cloud-to-ground lightning data are used in an observational study of two cases that produced severe weather in Catalonia (Spain). The first one occurred on 24 August 1993; a squall line crossed Catalonia from west to east producing heavy rain with rates of up to 100 mm h[minus sign]1 and hail of 7 cm

Clemente Ramis; Joan Arús; José Manuel López; Antoni M. Mestres

1997-01-01

47

Mobile vehicle road and weather observation quality check methods  

NASA Astrophysics Data System (ADS)

Today State Departments of Transportation rely more and more on road weather data to make maintenance decisions. Inaccurate data can result in wrong treatment applications or inadequate staffing levels to maintain the roadway at the desired level of service. Previous methods of road condition data reporting have been limited to static in situ sensor stations. These road weather information systems (RWIS) provide varied data about precipitation, winds, temperature, and more, but their siting does not always provide an accurate representation of weather and road conditions along the roadway. The use of mobile data collection from vehicles travelling the highway corridors may assist in the locations where RWIS sitings are sparse or non-existent. The United States Department of Transporation's "Connected Vehicle" (formally IntelliDrive) research project is designed to create a fully connected transportation system providing road and weather data collection from an extensive array of vehicles. While the implementation of Connected Vehicle is in the future, some of the theories and technologies are already in place today. Several states, as a part of the Pooled Fund Study Maintenance Decision Support System (MDSS), have equipped their winter maintenance vehicles with Mobile Data Collection Automated / Vehicle Location (MDC/AVL) systems. In addition, since 1996, automobiles sold in the United States are required to be equipped with an Onboard Diagnostic Version 2 (OBDII) port that streams live data from sensors located in and around the vehicle. While these sensors were designed for vehicle diagnostics, some of the data can be used to determine weather characteristics around the vehicle. The OBDII data can be collected by a smartphone and sent to a server in real time to be processed. These mobile systems may fill the information gap along the roads that stationary environmental sensor stations are not able to collect. Particular concern and care needs to be focused on data quality and accuracy, requiring the development of quality checks for mobile data collection. Using OBDII-equipped automobiles and mobile collection methods, we can begin to address issues of data quality by understanding, characterizing, and demonstrating the quality of mobile system observations from operational and research environments. Several forms of quality checking can be used, including range checks, Barnes spatial checks, comparing vehicle data to road weather models, and applying Clarus quality check methodologies and algorithms to mobile observations. Development of these quality checks can lead to the future integration of mobile data into the Clarus system, data implementation for improved forecasting, maintenance decision support, and traveler safety. This paper will discuss the benefits and challenges in mobile data collection, along with how the development and implementation of a system of quality checks will improve the quality and accuracy of mobile data collection.

Koller, Daniel Raymond

48

Effect of accelerated weathering on surface chemistry of modified wood  

Microsoft Academic Search

In this study, the effects of UV-light irradiation and water spray on colour and surface chemistry of scots pine sapwood samples were investigated. The specimens were treated with chromated copper arsenate (CCA), a metal-free propiconazol-based formulation, chitosan, furfuryl alcohol and linseed and tall oils. The weathering experiment was performed by cycles of 2h UV-light irradiation followed by water spray for

Ali Temiz; Nasko Terziev; Morten Eikenes; Jonas Hafren

2007-01-01

49

Surface Landing Site Weather Analysis for NASA's Constellation Program  

NASA Technical Reports Server (NTRS)

Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing of the Ares vehicles to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is art important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface weather conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center (MSFC) Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. This paper wiI1 describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that cab be obtained.

Altino, Karen M.; Burns, K. L.

2008-01-01

50

Global cloud climatology from surface observations  

SciTech Connect

Surface weather observations from stations on land and ships in the ocean are used to obtain the global distribution, at 5{sup o}x5{sup o} latitude-longitude resolution, of total cloud cover and the average amounts of the different cloud types: cumulus, cumulonimbus, stratus, stratocumulus, nimbostratus, altostratus, altocumulus, cirrus, cirrostratus, cirrocumulus, and fog. Diurnal and seasonal variations are derived, as well as interannual variations and multi-year trends. 3 refs., 3 figs.

Warren, S. [Univ. of Washington, Seattle, WA (United States)

1995-09-01

51

Surface ozone concentration trends and its relationship with weather types in Spain (2001-2010)  

NASA Astrophysics Data System (ADS)

This paper assesses the temporal variations of surface ozone concentrations during the period 2001-2010 in 3 regions of Spain with different geographical and socioeconomic features (northern coastland, central inland and northeast inland), as well as its link with atmospheric circulation. Specifically, daily surface atmospheric patterns over the aforementioned regions are characterized using NCEP/NCAR reanalysis data and an objective classification scheme in order to study the relationship between synoptic weather types and daily ozone levels. The results show that tropospheric ozone concentration has a tendency towards an increase during the study period, both during daytime and nighttime. Moreover, in general, this upward trend is seen throughout all of the seasons. The observed trends are in line with a reported decrease of NOX emissions and increase in surface solar radiation during the 2000s in Spain. On the other hand, interestingly, median concentrations were statistically significantly lower in days with anticyclonic weather conditions than in the rest of meteorological situations, while days with a directional weather type showed higher median levels of ozone concentration, with maximum values in days with northern and eastern component. Due to the detrimental effect that ozone has on human health, the relationship between synoptic weather patterns and daily ozone levels shown in this work could potentially be used for implementing pollution level alert protocols depending on forecast weather types.

Santurtún, Ana; González-Hidalgo, José Carlos; Sanchez-Lorenzo, Arturo; Zarrabeitia, María Teresa

2015-01-01

52

Observations of Heterogeneous Clouds and Weather in Substellar Atmospheres  

NASA Astrophysics Data System (ADS)

Atmospheres of cool brown dwarfs and gas giant planets share important similarities such as low temperatures, a rich molecular chemistry, condensate clouds, and rapid rotation. The combination of condensate clouds and rapid rotation has long motivated searches for weather phenomena on cool brown dwarfs. However, until recently, observations have failed to show compelling evidence for heterogeneous cloud features or giant storms that are commonplace within our own Solar System. Here we describe the most comprehensive variability survey of cool brown dwarfs to date. Our J-band search has targeted 50 isolated brown dwarfs over 60 nights at the DuPont 2.5-m telescope at Las Campanas with high cadence, high-precision photometric sequences, and is complemented by follow-up observations in additional bands in order to characterize the nature of the variations. Our data suggest that heterogeneous cloud features are responsible for variability (in one case as large as 30%) in a subset of partially cloudy brown dwarfs. Our results highlight the limitations of current 1D model atmospheres for brown dwarfs and extrasolar giant planets, and can be used to inform higher-dimensional modeling. In addition, variable brown dwarfs may provide a means of mapping winds and weather in ultracool atmospheres, thereby providing an empirical anchor for atmospheric circulation models in a new (non-irradiated, higher mass, rapidly rotating) physical regime.

Radigan, Jacqueline; Jayawardhana, R.; Lafreniere, D.; Artigau, E.

2011-09-01

53

Preserving the Nation's Weather and Climate History People have observed and recorded the weather for thousands of years. Native American petroglyphs often depict rain,  

E-print Network

Preserving the Nation's Weather and Climate History People have observed and recorded the weather, colonists from Europe began recording journal entries about the weather and natural environment they observed. By the late 1700s, accurate weather instruments, such as thermometers, were available

54

Two cases of severe weather in Catalonia (Spain): an observational study  

NASA Astrophysics Data System (ADS)

Surface observations, satellite and radar imagery and cloud-to-ground lightning data are used in an observational study of two cases that produced severe weather in Catalonia (Spain). The first one occurred on 24 August 1993; a squall line crossed Catalonia from west to east producing heavy rain with rates of up to 100 mm h[minus sign]1 and hail of 7 cm diameter. The observational information provided is a good tool for monitoring the event and issuing a reasonable nowcast. The second case, which occurred on 31 August 1994, was associated with the development of a tornado (F1 in the Fujita scale) as well as hail of up to 5 cm diameter. In this case the convection was almost stationary and no clear signatures of severe weather can be identified from available satellite and radar imagery.

Ramis, Clemente; Arús, Joan; López, José Manuel; Mestres, Antoni M.

1997-09-01

55

Surface weathering and dispersibility of MC252 crude oil.  

PubMed

Results from a comprehensive oil weathering and dispersant effectiveness study of the MC252 crude oil have been used to predict changes in oil properties due to weathering on the sea surface and to estimate the effective "time window" for dispersant application under various sea conditions. MC252 oil is a light paraffinic crude oil, for which approximately 55 wt.% will evaporate within 3-5 days when drifting on the sea. An unstable and low-viscosity water-in-oil (w/o) emulsion are formed during the first few days at the sea surface. This allows a high degree of natural dispersion when exposed to breaking wave conditions. Under calm sea conditions, a more stable and light-brown/orange colored water-in-oil (w/o) emulsion may start to form after several days, and viscosities of 10,000-15,000 mPa s can be achieved after 1-2 weeks. The "time window" for effective use of dispersants was estimated to be more than 1 week weathering at sea. PMID:25152185

Daling, Per S; Leirvik, Frode; Almås, Inger Kjersti; Brandvik, Per Johan; Hansen, Bjørn Henrik; Lewis, Alun; Reed, Mark

2014-10-15

56

Effect of accelerated weathering on surface chemistry of modified wood  

NASA Astrophysics Data System (ADS)

In this study, the effects of UV-light irradiation and water spray on colour and surface chemistry of scots pine sapwood samples were investigated. The specimens were treated with chromated copper arsenate (CCA), a metal-free propiconazol-based formulation, chitosan, furfuryl alcohol and linseed and tall oils. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes at the surface of the weathered samples were characterised by Fourier transform infrared spectroscopy (FT-IR); colour characterizations were performed by measuring CIELab parameters. The results show that all treatment methods except chitosan treatment provided lower colour changes than the control groups after 800 h exposure in weathering test cycle, but differences between chitosan and control were also small. The lowest colour changes were found on linseed oil (full cell process) and CCA treated wood. FT-IR results show that oil treatment (linseed and tall oil) decreased the intensities of a lignin specific peak (1500-1515 cm -1). Absorption band changes at 1630-1660 cm -1 were reduced by all treatments.

Temiz, Ali; Terziev, Nasko; Eikenes, Morten; Hafren, Jonas

2007-04-01

57

Direct observations of aluminosilicate weathering in the hyporheic zone of an Antarctic Dry Valley stream  

NASA Astrophysics Data System (ADS)

This study focused on chemical weathering and bacterial ecology in the hyporheic zone of Green Creek, a McMurdo Dry Valley (Antarctica) stream. An in situ microcosm approach was used to observe dissolution features on the basal-plane surface of muscovite mica. Four mica chips were buried in December 1999 and dug up 39 d later. Atomic force microscopy (AFM) of the basal-plane surfaces revealed small, anhedral ˜10-Å-deep etch pits covering ˜4% of the surfaces, from which an approximate basal-plane dissolution rate of 8.3 × 10 -18 mol muscovite cm -2 s -1 was calculated (on the basis of the geometric surface area) for the study period. This is an integrated initial dissolution rate on a fresh surface exposed for a relatively brief period over the austral summer and should not be compared directly to other long-term field rates. The observation of weathering features on mica agrees with previous stream- and watershed-scale studies in the Dry Valleys, which have demonstrated that weathering occurs where liquid water is present, despite the cold temperatures. AFM imaging of mica surfaces revealed biofilms including numerous small (<1 ?m long), rounded, oblong bacteria. The AFM observations agreed well with X-ray photoelectron microscopy results showing increased organic C and N. Bacteriologic analysis of the hyporheic zone sediments also revealed <1-?m-long bacteria. ?-Proteobacteria were observed, consistent with the oligotrophic conditions of the hyporheic zone. Nitrate-reducing bacteria were found, in agreement with a previous tracer test at Green Creek that suggested nitrate reduction occurs in the hyporheic zone. The results of this study thus provide direct evidence of dynamic geochemical and microbial processes in the hyporheic zone of a Dry Valley stream despite the extreme conditions; such processes were inferred previously from stream-scale hydrogeochemical studies.

Maurice, Patricia A.; McKnight, Diane M.; Leff, Laura; Fulghum, Julia E.; Gooseff, Michael

2002-04-01

58

Modeling apple surface temperature dynamics based on weather data.  

PubMed

The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

2014-01-01

59

Modeling Apple Surface Temperature Dynamics Based on Weather Data  

PubMed Central

The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management. PMID:25350507

Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

2014-01-01

60

Weathering  

NSDL National Science Digital Library

This interactive Flash resource provides information regarding physical and chemical weathering at an introductory physical geology or Earth science level. It includes animations, diagrams, and supplementary information and is suitable for high school or undergraduate students.

Smoothstone; Mifflin, Houghton

61

A statistical model for road surface friction forecasting applying optical road weather measurements  

NASA Astrophysics Data System (ADS)

Road surface friction is defined as the grip between car tyre and underlying surface. Poor friction often plays a crucial role in wintertime car accidents. Friction can decrease dramatically during snowfall or when wet road surface temperature falls below zero. Even a thin layer of ice or snow can decrease friction substantially increasing the risk of accidents. Many studies have shown that road surface temperature, road conditions and friction can fluctuate dramatically within short distances under specific weather situations. Friction or grip can be improved with road maintenance activities like salting and gritting. Salting will melt the ice or snow layer, whereas gritting will improve the grip. Salting is effective only above -5C temperatures. Light snowfall together with low temperatures can result in very slippery driving conditions. Finnish Road Administration's observing network covers c. 500 road weather stations in Finland. Almost 100 of them are equipped with optical sensors (in winter 2008-2009). The number of optical sensors has increased remarkably during past few years. The optical measuring devices are Vaisala DSC111 sensors which measure the depth of water, snow and ice on the road surface and also produce an estimate of the state of road and prevailing friction. Observation data from road weather stations with optical sensors were collected from winter 2007/08, and a couple of representative (from a weather perspective) stations were selected for detailed statistical analysis. The purpose of the study was to find a statistical relationship between the observed values and, especially, the correlation between friction and other road weather parameters. Consequently, a model based on linear regression was developed. With the model friction being the dependent variable, the independent variables having highest correlations were the composite of ice and snow (water content) on the road, and the road surface temperature. In the case of a wet road surface, the amount of water was the best predictor for friction. The models were tested with an independent sample from winter 2008/09. Finnish Meteorological Institute (FMI) has been running an operational road weather prediction model for about ten years. The model predicts e.g. the road surface temperature and the layers of snow, ice and water on the road. With the addition of the statistical friction model, road surface friction will be a new forecast parameter. There are, however, some challenges to be solved before operational applicability. A major issue is how to take road maintenance activities, and especially the salting, into account. This study is carried out within the EU/FP7 Project ROADIDEA, where the major frame of reference is to develop new and innovative products for traffic and transport sectors.

Hippi, M.; Juga, I.; Nurmi, P.

2009-09-01

62

Surface Meteorological Observation System (SMOS) Handbook  

SciTech Connect

The Surface Meteorological Observation System (SMOS) mostly uses conventional in situ sensors to obtain 1-minute, 30-minute, and 1440-minute (daily) averages of surface wind speed, wind direction, air temperature, relative humidity (RH), barometric pressure, and precipitation at the Central Facility and many of the extended facilities of the Southern Great Plains (SGP) climate research site. The SMOSs are not calibrated as systems. The sensors and the data logger (which includes the analog-to-digital converter, or A/D) are calibrated separately. All systems are installed using components that have a current calibration. SMOSs have not been installed at extended facilities located within about 10 km of existing surface meteorological stations, such as those of the Oklahoma Mesonet. The Surface Meteorological Observation Systems are used to create climatology for each particular location, and to verify the output of numerical weather forecast and other model output. They are also used to “ground-truth” other remote sensing equipment.

Ritsche, MT

2008-03-01

63

Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather  

PubMed Central

Severe and extreme weather is a major natural hazard all over the world, often resulting in major natural disasters such as hail storms, tornados, wind storms, flash floods, forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence, etc. can only be observed at close distances, lightning activity in these damaging storms can be monitored at all spatial scales, from local (using very high frequency [VHF] sensors), to regional (using very low frequency [VLF] sensors), and even global scales (using extremely low frequency [ELF] sensors). Using sensors that detect the radio waves emitted by each lightning discharge, it is now possible to observe and track continuously distant thunderstorms using ground networks of sensors. In addition to the number of lightning discharges, these sensors can also provide information on lightning characteristics such as the ratio between intra-cloud and cloud-to-ground lightning, the polarity of the lightning discharge, peak currents, charge removal, etc. It has been shown that changes in some of these lightning characteristics during thunderstorms are often related to changes in the severity of the storms. In this paper different lightning observing systems are described, and a few examples are provided showing how lightning may be used to monitor storm hazards around the globe, while also providing the possibility of supplying short term forecasts, called nowcasting.

Price, Colin

2008-01-01

64

WEATHER OBSERVATIONS - SUMMARY OF THE DAY - FIRST ORDER  

EPA Science Inventory

The National Climatic Data Center makes available daily weather data for approximately 300 currently active National Weather Service stations, with a lag time (after end of data month) of about 8-10 weeks. Coverage includes the contiguous United States, Caribbean Islands, Pacific...

65

Tropical Ocean Surface Energy Balance Variability: Linking Weather to Climate Scales  

NASA Technical Reports Server (NTRS)

Radiative and turbulent surface exchanges of heat and moisture across the atmosphere-ocean interface are fundamental components of the Earth s energy and water balance. Characterizing the spatiotemporal variability of these exchanges of heat and moisture is critical to understanding the global water and energy cycle variations, quantifying atmosphere-ocean feedbacks, and improving model predictability. These fluxes are integral components to tropical ocean-atmosphere variability; they can drive ocean mixed layer variations and modify the atmospheric boundary layer properties including moist static stability, thereby influencing larger-scale tropical dynamics. Non-parametric cluster-based classification of atmospheric and ocean surface properties has shown an ability to identify coherent weather regimes, each typically associated with similar properties and processes. Using satellite-based observational radiative and turbulent energy flux products, this study investigates the relationship between these weather states and surface energy processes within the context of tropical climate variability. Investigations of surface energy variations accompanying intraseasonal and interannual tropical variability often use composite-based analyses of the mean quantities of interest. Here, a similar compositing technique is employed, but the focus is on the distribution of the heat and moisture fluxes within their weather regimes. Are the observed changes in surface energy components dominated by changes in the frequency of the weather regimes or through changes in the associated fluxes within those regimes? It is this question that the presented work intends to address. The distribution of the surface heat and moisture fluxes is evaluated for both normal and non-normal states. By examining both phases of the climatic oscillations, the symmetry of energy and water cycle responses are considered.

Roberts, J. Brent; Clayson, Carol Anne

2013-01-01

66

Observational Calibration of Numerical Weather Prediction with Anomaly Integration  

NASA Astrophysics Data System (ADS)

Bias of numerical weather prediction (NWP) exists whenever because of the uncertainty of initial condition, model dynamics and physics. Perfect numerical solutions are therefore not accessible. The historical observations, however, record the real variation of atmosphere. The corresponding information can be used for NWP calibration. We developed an anomaly numerical-correction with observations (ANO) method for the NWP improvement with the help of historical reanalysis data. Tests and validations with several winter and summer case of sustained heavy rainfall in China show the nice effectiveness for improving circulation in NWP within two weeks. In a coarse CAM3.0 (T42 or T85) model configuration, the ANO correction extends numerical prediction by 1 day at the condition ACC > 0.6. Obvious improvement to ACC and RMSE of geopotential height, temperature, relative humidity and wind components is shown in both winter and summer cases. Correction to temperature at 500 hPa reaches 3.4 K in a winter storm case of 2008. In the tests, great calibration is observed at lower-latitude region, and the summer hemisphere is more obvious than the winter one. Out of thirty cases, 67% are significantly improved and the other 23% have a marginally amelioration. In addition to the circulation fields, we also verified the ANO for rainfall prediction using the nonhydrostatic WRF 3.5 model. Thirty-year hind cast is carried out using a three-region nesting configuration. The highest resolution is 4 km. Increase of ACC and decrease of RMSE is also shown for geopotential height in the high-resolution numerical prediction, and the accumulated rainfall illustrates also general amelioration in both amount and the position when the same ANO correction is used. Due its spatial and temporal discontinuity of precipitation, the effect of ANO is not that significant as for circulation fields. In the presentation, we will show more detailed verification of the correction in several heavy rainfall cases and the application for daily numerical prediction.

Peng, Xindong; Che, Yuzhang; Chang, Jun

2014-05-01

67

Weather  

NSDL National Science Digital Library

In the project you will learn about thunderstorms and tornadoes and play a weather matching game. What exactly are thunderstorms and tornadoes? Use your T- chart to explain some facts about a thunderstorm and a tornado as we review each. T-Chart Begin by reviewing what a thunderstorm is and how they form. Thunderstorm information What is a thunderstorm? What are thunderstorms most likely to occur? What causes thunder? Next review what a tornado ...

Caitlin, Ms.

2009-10-21

68

Weather Observer, 15-1. Military Curriculum Materials for Vocational and Technical Education.  

ERIC Educational Resources Information Center

This course, adapted from military curriculum materials for use in vocational and technical education, was designed to upgrade an apprentice weather observer to the weather observer specialist level. Intended to be used in a laboratory or on-the-job learning situation, it contains both basic information needed for review and supervisory…

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

69

Geomorphic controls on mineral weathering, elemental transport, and production of mineral surface area in a schist bedrock weathering profile, Piedmont Pennsylvania  

NASA Astrophysics Data System (ADS)

We assess a deep chemical weathering profile in the context of geomorphic evolution in the Laurels Schist, a late proterozoic greenschist formation in the Christina River Basin Critical Zone Observatory located in the Piedmont region in southeastern Pennsylvania. Two 21-meter deep rotosonic drill cores were sampled at the ridge top and footslope positions in a first-order, forested watershed. The top meter was sampled at high-resolution in a soil pit adjacent to each drill core and along a hillslope transect to assess geomorphic controls on the weathering profile. Weathering processes in soil and saprolite were examined by observing changes in mineralogy, including the emergence of secondary phyllosilicate and oxide minerals; measuring specific surface area of bulk soil and saprolite; and by quantifying elemental mass changes of major and minor rock-forming elements. Mineral profiles were assessed using clay and bulk XRD, and reveal that kaolinite, a common secondary phyllosilicate, is present above 1.5 meters in the weathering profile. Specific surface area (SSA) values decrease with increasing depth to a critical depth around 2 meters, where the values of untreated (carbon-loaded) and muffled (carbon removed by heating) mineral grains converge to baseline SSA values below 10 m2g-1, indicating that carbon is sorbed with mineral surface area in the upper 2 meters. Immobile element concentrations decrease with increasing depth up to 3 meters, indicating that the preferential removal of mobile elements extends beyond the depth of C-mineral adsorption. Variability of immobile elements in the deep weathering profile reveal variations that could be the result of weathering in fractures but are more likely inherited by the rock composition and particle size of pre-metamorphosed parent rock.

Wenell, B.; Yoo, K.; Aufdenkampe, A. K.; Mahoney, J. B.; Lepak, L.

2013-12-01

70

Space Weathering Impact on Solar System Surfaces and Planetary Mission Science  

NASA Astrophysics Data System (ADS)

We often look “through a glass, darkly” at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compositional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer term (e.g., solar cycle) evolution of space climate. Capable instrumentation on planetary missions can and should be planned to contribute to knowledge of interplanetary space environments. Evolving data system technologies such as virtual observatories should be explored for more interdisciplinary application to the science of planetary surface, atmospheric, magnetospheric, and interplanetary interactions.

Cooper, J. F.; Hartle, R. E.; Sittler, E. C.; McGrath, M. A.; Alexander, C. J.; Dalton, J. B.; Pascu, D.; Paranicas, C.; Hibbitts, C.; Hill, M. E.; Cooper, P. D.; Johnson, R. E.; Cassidy, T. A.; Orlando, T. M.; Lanzerotti, L. J.; Schwadron, N. A.; Retherford, K. D.; Kaiser, R. I.; Leblanc, F.; Sturner, S. J.; Killen, R. M.

2009-12-01

71

Space Weathering Impact on Solar System Surfaces and Planetary Mission Science  

NASA Technical Reports Server (NTRS)

We often look "through a glass, darkly" at solar system bodies with tenuous atmospheres and direct surface exposure to the local space environment. Space weathering exposure acts via universal space-surface interaction processes to produce a thin patina of outer material covering, potentially obscuring endogenic surface materials of greatest interest for understanding origins and interior evolution. Examples of obscuring exogenic layers are radiation crusts on cometary nuclei and iogenic components of sulfate hydrate deposits on the trailing hemisphere of Europa. Weathering processes include plasma ion implantation into surfaces, sputtering by charged particles and solar ultraviolet photons, photolytic chemistry driven by UV irradiation, and radiolytic chemistry evolving from products of charged particle irradiation. Regolith structure from impacts, and underlying deeper structures from internal evolution, affects efficacy of certain surface interactions, e.g. sputtering as affected by porosity and surface irradiation dosage as partly attenuated by local topographic shielding. These processes should be regarded for mission science planning as potentially enabling, e.g. since direct surface sputtering, and resultant surface-bound exospheres, can provide in-situ samples of surface composition to ion and neutral mass spectrometers on orbital spacecraft. Sample return for highest sensitivity compOSitional and structural analyses at Earth will usually be precluded by limited range of surface sampling, long times for return, and high cost. Targeted advancements in instrument technology would be more cost efficient for local remote and in-situ sample analysis. More realistic laboratory simulations, e.g. for bulk samples, are needed to interpret mission science observations of weathered surfaces. Space environment effects on mission spacecraft and science operations must also be specified and mitigated from the hourly to monthly changes in space weather and from longer term (e.g., solar cycle) evolution of space climate. Capable instrumentation on planetary missions can and should be planned to contribute to knowledge of interplanetary space environments. Evolving data system technologies such as virtual observatories should be explored for more interdisciplinary application to the science of planetary surface, atmospheric, magnetospheric, and interplanetary interactions.

Cooper, John F.

2011-01-01

72

Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations  

NASA Technical Reports Server (NTRS)

Today s presentation describes how real time space weather data is used by the International Space Station (ISS) space environments team to obtain data on auroral charging of the ISS vehicle and support ISS crew efforts to obtain auroral images from orbit. Topics covered include: Floating Potential Measurement Unit (FPMU), . Auroral charging of ISS, . Real ]time space weather monitoring resources, . Examples of ISS auroral charging captured from space weather events, . ISS crew observations of aurora.

Minow, Joseph; Pettit, Donald R.; Hartman, William A.

2012-01-01

73

Chitinophaga qingshengii sp. nov., isolated from weathered rock surface.  

PubMed

A novel type of mineral-weathering bacterium was isolated from weathered rock (potassic trachyte) surfaces collected from Nanjing (Jiangsu, China). Cells of strain JN246T were Gram-stain-negative, rod-shaped, and non-motile. Strain JN246T was aerobic, catalase- and oxidase-positive, and grew optimally at 28 °C and pH 7.0. On the basis of 16S rRNA gene sequence analysis, strain JN246T belonged to the genus Chitinophaga and the closest phylogenetic relatives were Chitinophaga eiseniae YC6729T (98.5 %), Chitinophaga terrae KP01T (96.8 %), and Chitinophaga jiangningensis JN53T (96.3 %). The major respiratory quinine was MK-7 and the major polyamine was homospermidine. The major fatty acids were iso-C15:0, C16:1?5c, C16:0, iso-C17:0 3-OH, iso-C15:0 3-OH, C14:O, C16:0 3-OH, C16:1?7c and/or C16:1?6c (summed feature 3), and C13:1. The polar lipid profile of strain JN246T consisted of phosphatidylethanolamine, unknown aminolipids and unknown lipids. The genomic DNA G + C content of strain JN246T was 48.8 mol%. Based on the low level of DNA-DNA relatedness (ranging from 22.6 % to 42.4 %) to these type strains of species of the genus Chitinophaga and unique phenotypic characteristics, strain JN246T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga qingshengii sp. nov. is proposed. The type strain is JN246T (= CCTCC AB 2014201 T= JCM 30026 T). PMID:25342110

Cheng, Cheng; Wang, Qi; He, Lin-Yan; Huang, Zhi; Sheng, Xia-Fang

2014-10-23

74

Data assimilation of dead fuel moisture observations from remote automated weather stations  

E-print Network

Fuel moisture has a major influence on the behavior of wildland fires and is an important underlying factor in fire risk assessment. We propose a method to assimilate dead fuel moisture content observations from remote automated weather stations (RAWS) into a time-lag fuel moisture model. RAWS are spatially sparse and a mechanism is needed to estimate fuel moisture content at locations potentially distant from observational stations. This is arranged using a trend surface model (TSM), which allows us to account for the effects of topography and atmospheric state on the spatial variability of fuel moisture content. At each location of interest, the TSM provides a pseudo-observation, which is assimilated via Kalman filtering. The method is tested with the time-lag fuel moisture model in the coupled weather-fire code WRF-SFIRE on 10-hr fuel moisture content observations from Colorado RAWS in 2013. We show using leave-one-out testing that the TSM compares favorably with inverse squared distance interpolation as u...

Vejmelka, Martin; Mandel, Jan

2014-01-01

75

Introduction to GOES-R and the Next Generation Weather and Observation Constellations  

NASA Astrophysics Data System (ADS)

The Earth Observing community is preparing for the next generation of weather and observation remote sensing systems. These systems are constellations that provide a much richer sensor suite that provides significant increases in data rates, types of data and resultant volumes. In this new era weather and observation data are made more integrated, and multiple mechanisms for accessing this data and dedicated services that leverage it will be made available. The purpose of this presentation will be to introduce this next generation of weather and observation constellations, including the GOES-R system as an example, and to provide a platform for other presentations in this session.

Burnett, M.; Krause, R. G.

2012-12-01

76

Exploring the Terrestrial Ecosystem Response to Extreme Weather Events using Multiple Land Surface Models  

NASA Astrophysics Data System (ADS)

This study investigates the complex terrestrial ecosystems response to extreme weather events using three different land surface models. Previous studies have showed that extreme weather events can have serious and damaging impacts on human and natural systems and they are most evident on regional and local scales. Under climate change, extreme weather events are likely to increase in both magnitude and frequency, making realistic simulation of ecosystems response to extreme events more essential than ever in assessing the potential damaging impacts. Three different land surface models are used to explore the impacts of extreme events on regional to continental ecosystem responses. The Terrestrial Ecosystem Model (TEM) is a process-based ecosystem model that uses spatially referenced information on climate, elevation, soils, vegetation and water availability to make monthly estimates of vegetation and soil carbon and nitrogen fluxes and pool sizes. The Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) is a multi-layered land surface model based on eddy-covariance theory to calculate the biosphere-atmosphere exchanges of carbon dioxide, water, and momentums. The Community Land Model (CLM) is a community-based model widely used in global-scale land data assimilation research. The study focuses on the complex interactions and feedbacks between the terrestrial ecosystem and the atmosphere such as water cycle, carbon and nitrogen budgets, and environmental conditions. The model simulations and performances are evaluated using the biogeophysical and micrometeorological observation data from the AmeriFlux sites across the continental US. This study compares and evaluates the ability of different models and their key components to capture terrestrial response to extreme weather events.

Xu, L.; Schlosser, C. A.; Kicklighter, D. W.; Felzer, B. S.; Monier, E.; Paw U, K.

2012-12-01

77

he Cooperative Observer Program is a unique partnership between the National Weather Service  

E-print Network

sites support local weather, climate and flood forecasts, data from 1,221 of them also contribute the extent of climate change from local to global scales. In addition, data collected by weather observers help local officials make long-term planning decisions about water resources and are used by a variety

78

MY NASA DATA: State of the Atmosphere - Interpreting Weather Observations  

NSDL National Science Digital Library

This lesson consists of three activities. Students will discover the effect of temperature and pressure on cloud formation, analyze weather balloon data, and interpret a graph created from the synthesis of data sets on temperature, relative humidity and dew point. This lesson uses student- and citizen science-friendly microsets of authentic NASA Earth system science data from the MY NASA DATA project. It includes related links.

2012-08-03

79

Impact of various observing systems on weather analysis and forecast over the Indian region  

NASA Astrophysics Data System (ADS)

investigate the potential impact of various types of data on weather forecast over the Indian region, a set of data-denial experiments spanning the entire month of July 2012 is executed using the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system. The experiments are designed to allow the assessment of mass versus wind observations and terrestrial versus space-based instruments, to evaluate the relative importance of the classes of conventional instrument such as radiosonde, and finally to investigate the role of individual spaceborne instruments. The moist total energy norm is used for validation and forecast skill assessment. The results show that the contribution of wind observations toward error reduction is larger than mass observations in the short range (48 h) forecast. Terrestrial-based observations generally contribute more than space-based observations except for the moisture fields, where the role of the space-based instruments becomes more prevalent. Only about 50% of individual instruments are found to be beneficial in this experiment configuration, with the most important role played by radiosondes. Thereafter, Meteosat Atmospheric Motion Vectors (AMVs) (only for short range forecast) and Special Sensor Microwave Imager (SSM/I) are second and third, followed by surface observations, Sounder for Probing Vertical Profiles of Humidity (SAPHIR) radiances and pilot observations. Results of the additional experiments of comparative performance of SSM/I total precipitable water (TPW), Microwave Humidity Sounder (MHS), and SAPHIR radiances indicate that SSM/I is the most important instrument followed by SAPHIR and MHS for improving the quality of the forecast over the Indian region. Further, the impact of single SAPHIR instrument (onboard Megha-Tropiques) is significantly larger compared to three MHS instruments (onboard NOAA-18/19 and MetOp-A).

Singh, Randhir; Ojha, Satya P.; Kishtawal, C. M.; Pal, P. K.

2014-09-01

80

Titan's rotation - Surface feature observed  

NASA Astrophysics Data System (ADS)

A surface feature or a near-surface fracture is suggested to account for the time variations in the 0.94, 1.08, and 1.28 micron atmospheric windows of Titan's geometric albedo, relative to its albedo in adjacent methane bands. These observations are noted to be consistent with synchronous rotation. They can also be explained by a 0.1-higher surface albedo on Titan's leading hemisphere.

Lemmon, M. T.; Karkoschka, E.; Tomasko, M.

1993-06-01

81

Characterizing the process and quantifying the rate of subaerial rock weathering on desert surfaces using roughness analysis  

NASA Astrophysics Data System (ADS)

Subaerial weathering of rocks is a common process observed on desert surfaces on Earth and other planetary terrestrial surfaces such as on Mars. On Earth, this weathering process has been previously identified as one of the key erosion agent driving geomorphic surface evolution and the development of desert pavements. And yet, fundamental aspects of the process, such as the relative contribution of the different weathering modes that drive it (e.g., mechanical breakdown of rocks, chemical weathering, aeolian abrasion and exfoliation) as well as the rate by which this weathering process occurs have not been systematically examined. Here, we present a new approach for quantitatively addressing these fundamental aspects of process geomorphology on desert surfaces. We focus here on co-genetic desert alluvial surfaces of different ages, i.e. alluvial chronosequences, which provide excellent recorders for the evolution of boulder-strewn surfaces into smooth desert pavements through in-situ subaerial weathering of rocks. Our approach combines independent measures of two different surface attributes: High resolution (mm-scale) 3D ground-based laser scanning (LiDAR) of surface micro-topography, and numerical dating of surface age. Roughness analysis of the LiDAR data in power spectral density (PSD) space allows us to characterize the geometric manifestation of rock weathering on the surface and to distinguish between the different weathering modes. Numerical age constraints provide independent estimates for the time elapsed since the process began. Accordingly, we are able to constrain surface roughness evolution on alluvial fan desert chronosequences through time, and present PSD analysis of surface roughness as a new quantitative tool to examine the process of subaerial rock weathering in desert environments. In this study we present results from two late Quaternary alluvial chronosequences along the Dead Sea Transform in the hyper-arid Negev desert of southern Israel. LiDAR scanning was applied on representative areas (~30-50 m2) of 10 separate surfaces ranging from rough Holocene surfaces to fairly smooth surfaces with well-developed pavements displaying an OSL age of 87 kyr. We find typical and recurring time-dependent changes in the offset as well as shape of the PSD curves in both chronosequences: PSD offset is continuously reduced over time reflecting the overall reduction in the amplitude of roughness at all wavelengths. The PSD curves display progressive moderation of slopes at the longer wavelengths with the moderation point itself systematically shifted to shorter wavelengths. This characteristic evolution of PSD offset and slope moderation at longer wavelengths reflects the typical break up of boulder-sized clasts through time as the surfaces mature into well-developed desert pavements and points towards mechanical breakdown as the dominant weathering mode. In addition, we are able to determine the rate by which the larger clasts are removed from the system. We build on these new insights into process and rate of rock weathering to propose PSD analysis of surface roughness as a complementary method for constraining the age of desert alluvial surfaces in places where 'conventional' dating cannot be applied.

Mushkin, Amit; Sagy, Amir; Trabelci, Eran

2013-04-01

82

A comparison between weather simulated within the Erosion/Productivity Impact Calculator (EPIC) and observed data  

E-print Network

A COMPARISON BETWEEN WEATHER SIMULATEDWITHINTHE EROSION/PRODUCTIVITY IMPACT CALCULATOR (EPIC) AND OBSERVED DATA A Thesis by TREVOR W. R. WALLIS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1992 Major Subject: Meteorology A COMPARISON BETWEEN WEATHER SIMULATED WITHIN THE EROSION/PRODUCTIVITY IMPACT CALCULATOR (EPIC) AND OBSERVED DATA A Thesis by TREVOR W. R. WALLIS Approved...

Wallis, Trevor W.R

1992-01-01

83

Correlation of the Abundance of Betaproteobacteria on Mineral Surfaces with Mineral Weathering in Forest Soils  

PubMed Central

Pyrosequencing-based analysis of 16S rRNA gene sequences revealed a significant correlation between apatite dissolution and the abundance of betaproteobacteria on apatite surfaces, suggesting a role for the bacteria belonging to this phylum in mineral weathering. Notably, the cultivation-dependent approach demonstrated that the most efficient mineral-weathering bacteria belonged to the betaproteobacterial genus Burhkolderia. PMID:22798365

Lepleux, C.; Turpault, M. P.; Oger, P.; Frey-Klett, P.

2012-01-01

84

Surface observations for the evaluation of geophysical measurements from Seasat  

NASA Technical Reports Server (NTRS)

The surface observations used for direct comparison with Seasat-derived values at fixed locations and as input to analyzed fields of pressure, wind, air and sea temperatures, and surface dew point are discussed. These included measurements made by research vessels participating in the Gulf of Alaska Seasat Experiment (GOASEX) and NOAA research platforms in addition to aircraft observations and reports from the World Weather Watch. The application of these observations in describing the synoptic-scale winds over the ocean is discussed, and the sensitivity of the verification statistics to the type of data (observations from buoys, weather ships, and transient vessels with or without anemometers) is considered. Results of a preliminary comparison of wind fields derived from Seasat-A scatterometer observation with winds specified by several types of platforms are presented.

Wilkerson, J. C.; Brown, R. A.; Cardone, V. J.; Coons, R. E.; Loomis, A. A.; Woiceshyn, P. M.; Overland, J. E.; Peteherych, S.; Pierson, W. J.; Wurtele, M. G.

1979-01-01

85

Observations and simulations of physical and biological processes at ocean weather station P, 1951-1980  

NASA Astrophysics Data System (ADS)

Physical and biological processes in the mixed layer at ocean weather station (OWS) P (50°N, 145°W) over a 30-year period (1951-1980) were investigated using observations and model simulations. The observations include 30 years of surface meteorological and sea surface temperature data collected at OWS P and Ekman upwelling velocities derived from the Comprehensive Ocean-Atmosphere Data Set, 14 years (1953-1966) of daily temperature profiles, nearly 150 chlorophyll a profiles spanning all months of the year, monthly climatological solar irradiances, and 0- to 50-m integrated nitrate concentrations. The simulations incorporated models for the estimation of surface solar downwelling irradiance, surface heat fluxes, subsurface diffuse attenuation, mixed layer dynamics, and biological processes. The time-dependent model inputs were the surface observations of cloud cover, air temperature, dew point temperature, and wind speed. The atmospheric irradiance, marine diffuse attenuation, and mixed layer models were adapted from existing models developed by others. The biological model, developed by the authors, has four components (nitrate, ammonium, phytoplankton nitrogen, and zooplankton nitrogen) and computes a variety of additional quantities, including chlorophyll a concentration and gross and new production. Model comparisons with in situ time series showed that predictions of sea surface temperature and mixed layer depth were reasonably accurate. Climatological monthly profiles of chlorophyll a and temperature were within 1 standard deviation of the observed values at nearly all depths. Also, the climatological annual cycles of solar irradiance and 0- to 50-m integrated nitrate accurately reproduced observed values. Annual primary production was estimated to be ˜190 g C m-2 yr-1 and varied by no more than ±5% in any year. This estimate is consistent with recent observations but is much greater than earlier estimates, indicating that carbon cycling in the North Pacific is much more important to the global carbon budget than previously thought. Significant interannual variability in sea surface temperature, Ekman upwelling, mixed layer depth, and surface nitrate concentration had little impact on productivity. The model also indicates that the nitrate supply to the euphotic zone is very sensitive to Ekman upwelling and that amplification of the wind stress curl can result in complete nitrate depletion when the winds are persistently downwelling favorable.

McClain, Charles R.; Arrigo, Kevin; Tai, King-Sheng; Turk, Daniella

1996-02-01

86

Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization  

USGS Publications Warehouse

Naturally weathered feldspar surfaces in the Jurassic Navajo Sandstone at Black Mesa, Arizona, was characterized with high-resolution transmission and analytical electron microscope (HRTEM-AEM) and field emission gun scanning electron microscope (FEG-SEM). Here, we report the first HRTEM observation of a 10-nm thick amorphous layer on naturally weathered K-feldspar in currently slightly alkaline groundwater. The amorphous layer is probably deficient in K and enriched in Si. In addition to the amorphous layer, the feldspar surfaces are also partially coated with tightly adhered kaolin platelets. Outside of the kaolin coatings, feldspar grains are covered with a continuous 3-5 ??m thick layer of authigenic smectite, which also coats quartz and other sediment grains. Authigenic K-feldspar overgrowth and etch pits were also found on feldspar grains. These characteristics of the aged feldspar surfaces accentuate the differences in reactivity between the freshly ground feldspar powders used in laboratory experiments and feldspar grains in natural systems, and may partially contribute to the commonly observed apparent laboratory-field dissolution rate discrepancy. At Black Mesa, feldspars in the Navajo Sandstone are dissolving at ???105 times slower than laboratory rate at comparable temperature and pH under far from equilibrium condition. The tightly adhered kaolin platelets reduce the feldspar reactive surface area, and the authigenic K-feldspar overgrowth reduces the feldspar reactivity. However, the continuous smectite coating layer does not appear to constitute a diffusion barrier. The exact role of the amorphous layer on feldspar dissolution kinetics depends on the origin of the layer (leached layer versus re-precipitated silica), which is uncertain at present. However, the nanometer thin layer can be detected only with HRTEM, and thus our study raises the possibility of its wide occurrence in geological systems. Rate laws and proposed mechanisms should consider the possibility of this amorphous layer on feldspar surface. ?? 2006 Elsevier Inc. All rights reserved.

Zhu, C.; Veblen, D.R.; Blum, A.E.; Chipera, S.J.

2006-01-01

87

WHAT TO DO DURING SEVERE WEATHER WHILE ON CAMPUS If you observe a tornado/severe weather, you hear tornado sirens sound or receive a  

E-print Network

WHAT TO DO DURING SEVERE WEATHER WHILE ON CAMPUS If you observe a tornado/severe weather, you hear tornado sirens sound or receive a tornado warning emergency notification from the University: If outside, this will be a closet or hall. Do not seek refuge in an automobile. A tornado warning emergency notification from

Oklahoma, University of

88

Soil Characteristics Related to Weathering and Pedogenesis Across a Geomorphic Surface of Uniform Age in Michigan  

Microsoft Academic Search

Our study explores the range of pedogenic development and near-surface weathering on a large (>250,000 ha) geomorphic surface in northern lower Michigan, via the examination of four typical soils. The surface is associated with proglacial outwash from the Port Huron advance of the Laurentide ice sheet, dated at about 13 ka. In a GIS we determined the four most extensive

Randall J. Schaetzl; Leslie R. Mikesell; Michael A. Velbel

2006-01-01

89

Study of Ionospheric Response to Space Weather Disturbances in Three Dimensions Using the GPS Observation System  

Microsoft Academic Search

The Global Positioning System GPS satellites and global as well as regional networks of hundreds to thousands of ground-based permanent GPS receiver stations have become an unprecedented space weather observation system since the beginning of the new millennium The GPS observables namely carrier phase and pseudorange as well as signal power can be processed to retrieve ionospheric measurements along the

X. Pi; A. J. Mannucci; B. A. Iijima; A. Komjathy

2006-01-01

90

Analysis of fog occurrence on E11-A75 Motorway, with weather station data in relation to satellite observation  

NASA Astrophysics Data System (ADS)

Transport is often disturbed in wintertime by fog occurrence causing delay. Fog may also be responsible for dramatic accidents causing injuries and fatalities. For meteorological weather services, fog is defined as when visibility is less than 1000 m. However, for road traffic, when visibility becomes less than 200 m, fog is considered a traffic hazard for road transport. Fog forecast remains a difficult task. Satellite observation combined with surface measurements by a network of road weather stations can provide short-term information that could be useful to assist traffic authorities in taking decisions relating to traffic control measures or drivers information. Satellite images allow to identify cloud types and to establish a map of the risk of fog occurrence. The surface measurements help to discriminate between low clouds and fog. The analysis method has already been tested last winter on some case studies on the motorway E11-A75 in Auvergne region in France, thanks to a network of 15 weather stations along the 300 km of motorway. In the highest area that is between 580 and 1100 m, the value of the relative humidity has been analysed in relation to the visibility measured by a diffusiometer and the observations of road maintenance staff. The main results will be presented and connected to the traditional synoptic network of Météo-France. In order to improve the map of fog risks, the requirement to have relevant data has been pointed out, especially for the relative humidity near the ground surface (i.e. 2 m above the ground). To go further in this investigation, one weather station, at the Col de la Fageole, has been identified as having the greatest occurrence of dense fog, i.e. less than 200 m. Then it has been decided to enrich the instrumentation at this observation point later on with a present weather sensor and with a camera. This paper will focus on the physical data of the weather station. It will be examined how the additional data of the new sensor, the meteorological visibility and the discrimination of the nature of precipitation will help to improve the analysis.

Colomb, M.; Bernardin, F.; Favier, B.; Mallet, E.; Laurantin, O.

2010-07-01

91

The elasticity of the epidemic growth rate to observed weather patterns with an application to yellow rust.  

PubMed

ABSTRACT We extend a previously developed method that quantifies the sensitivity of the exponential epidemic growth rate, r, to weather changes, through a pathogen's life cycle components (basic reproduction number, latent period, and mean and standard deviation of the spore production curve). Here a method is developed to study the elasticities of the system and subsequently the model is linked to observed weather patterns. This enables a direct comparison between the effects of different weather variables (temperature, surface wetness duration, and light quantity) under realistic weather scenarios. The three sites studied represent areas within the United Kingdom with contrasting climates. Yellow rust, caused by Puccinia striiformis, on winter wheat is studied as a key application. Our results show that temperature and more importantly changes in temperature through their effect on pathogen reproduction have the largest effect on r. The long latent period at low winter temperatures is not a key component in the epidemic development, which is contrary to general beliefs. The results combined with long term average yellow rust severity patterns show that it is winter survival and not summer survival that controls the eventual disease severity. The results also show that within the current United Kingdom spraying regime on wheat crops against yellow rust, the first spray should mainly affect the basic reproduction number, i.e., should be a protectant spray, whereas the second spray should also affect the latent period, i.e., should also have curative action. PMID:18943522

van den Berg, F; van den Bosch, F

2007-11-01

92

Investigation of changes in surface properties of bituminous coal during natural weathering processes by XPS and SEM  

NASA Astrophysics Data System (ADS)

In this investigation, XPS and SEM were used to indicate the changes in surface properties of bituminous coal during natural weathering processes. Natural weathering processes of bituminous coal were conducted on the roof. XPS results showed that the content of CC and CH groups on bituminous coal surface decreased but the content of CO, CO, and OCO groups increased after natural weathering processes. Meanwhile, the contents of Al and Si elements on bituminous coal surface were also increased. SEM results showed that the surface roughness of bituminous coal was increased after natural weathering processes. Natural weathering processes not only changed surface chemical composition of bituminous coal but also changed surface topography of bituminous coal. In addition, natural weathering processes made bituminous coal surface more hydrophilic.

Xia, Wencheng; Yang, Jianguo; Liang, Chuan

2014-02-01

93

Rates of oxidative weathering on the surface of Mars  

NASA Technical Reports Server (NTRS)

A model of acid weathering is proposed for the iron-rich basalts on Mars. Aqueous oxidation of iron sulfides released SO4(2-) and H(+) ions that initiated the dissolution of basaltic ferromagnesian silicates and released Fe(2+) ions. The Fe(2+) ions eventually underwent ferrolysis reactions and produced insoluble hydrous ferric oxide phases. Measurements of the time-dependence of acid weathering reactions show that pyrrhotite is rapidly converted to pyrite plus dissolved ferrous iron, the rate of pyrite formation decreasing with rising pH and lower temperatures. On Mars, oxidation rates of dissolved Fe(2+) ions in equatorial melt-waters in contact with the atmosphere are estimated to lie in the range 0.3-3.0 ppb Fe/yr over the pH range 2 to 6. Oxidation of Fe(2+) ions is estimated to be extremely slow in brine eutectic solutions that might be present on Mars and to be negligible in the frozen regolith.

Burns, Roger G.; Fisher, Duncan S.

1993-01-01

94

Rates of oxidative weathering on the surface of Mars  

NASA Astrophysics Data System (ADS)

A model of acid weathering is proposed for the iron-rich basalts on Mars. Aqueous oxidation of iron sulfides released SO4(2-) and H(+) ions that initiated the dissolution of basaltic ferromagnesian silicates and released Fe(2+) ions. The Fe(2+) ions eventually underwent ferrolysis reactions and produced insoluble hydrous ferric oxide phases. Measurements of the time-dependence of acid weathering reactions show that pyrrhotite is rapidly converted to pyrite plus dissolved ferrous iron, the rate of pyrite formation decreasing with rising pH and lower temperatures. On Mars, oxidation rates of dissolved Fe(2+) ions in equatorial melt-waters in contact with the atmosphere are estimated to lie in the range 0.3-3.0 ppb Fe/yr over the pH range 2 to 6. Oxidation of Fe(2+) ions is estimated to be extremely slow in brine eutectic solutions that might be present on Mars and to be negligible in the frozen regolith.

Burns, R. G.; Fisher, D. S.

1993-02-01

95

MODELING LAND SURFACE PROCESSES IN SHORT-TERM WEATHER AND CLIMATE STUDIES  

E-print Network

288 MODELING LAND SURFACE PROCESSES IN SHORT-TERM WEATHER AND CLIMATE STUDIES ZONG-LIANG YANG@mail.utexas.edu Website: www.geo.utexas.edu/climate (Manuscript received 31 January 2003) Land exchanges momentum, energy, water, aerosols, carbon dioxide and other trace gases with its overlying atmosphere. The land surface

Yang, Zong-Liang

96

THE LINK BETWEEN CLAY MINERAL WEATHERING AND THE FORMATION OF NI SURFACE PRECIPITATES  

E-print Network

THE LINK BETWEEN CLAY MINERAL WEATHERING AND THE FORMATION OF NI SURFACE PRECIPITATES Andreas C minerals may proceed via formation of surface precipitates, which may lead to a significant long may precipitate from pure metal solutions, the formation of layered double hydroxides (LDH) and of 1

Sparks, Donald L.

97

Surface Meteorological Observation System (SMOS)  

NSDL National Science Digital Library

These middle/junior high school activities require students to find and graph factors such as wind chill and relative humidity for up to a month, drawing from datasets available on the Internet or from local sources. Students then hypothesize relationships between pairs of factors, and test their ideas using data from a site in Oklahoma with a Surface Meteorological Observation System (SMOS). The activities are part of the Atmospheric Visualization Collection (AVC), which focuses on data from the Atmospheric Radiation Measurement (ARM) program's Southern Great Plains (SGP) Cloud and Radiation Testbed site.

Mccollum, Tim

2003-01-01

98

Offline land surface temperature assimilation in mumerical weather prediction output  

Technology Transfer Automated Retrieval System (TEKTRAN)

Land surface temperature plays an important role in land surface processes, and it is a key input to physically-based retrieval algorithms of important hydrological states and fluxes, such as soil moisture and evaporation. For this reason there are many independent estimates of land surface temperat...

99

HOW DOES SPACE WEATHERING DEPEND ON THE SURFACE CONDITION OF AIRLESS BODIES (ASTEROIDS, THE MOON, AND MERCURY)? S. Sasaki1  

E-print Network

HOW DOES SPACE WEATHERING DEPEND ON THE SURFACE CONDITION OF AIRLESS BODIES (ASTEROIDS, THE MOON, spectral redden- ing, and attenuation of absorption bands in time. Space weathering is considered confirmed the formation of nanophase ion is responsible for the space weathering [6-10]. Itokawa has changed

Hiroi, Takahiro

100

Optimal Sites for Supplementary Weather Observations: Simulation with a Small Model  

Microsoft Academic Search

Anticipating the opportunity to make supplementary observations at locations that can depend upon the current weather situation, the question is posed as to what strategy should be adopted to select the locations, if the greatest improvement in analyses and forecasts is to be realized. To seek a preliminary answer, the authors introduce a model consisting of 40 ordinary differential equations,

EDWARD N. LORENZ; KERRY A. EMANUEL

2004-01-01

101

Optimal Sites for Supplementary Weather Observations: Simulation with a Small Model  

Microsoft Academic Search

ABSTRACT Anticipating the opportunity to make,supplementary,observations at locations that can depend upon the current weather situation, the question is posed as to what strategy should be adopted to select the locations, if the greatest improvement in analyses and forecasts is to be realized. To seek a preliminary answer, the authors introduce a model consisting of 40 ordinary differential equations, with

Edward N. Lorenz; Kerry A. Emanuel

1998-01-01

102

Total Lightning Observations of Extreme Weather Events over the Contiguous United States  

Microsoft Academic Search

The overall objective is to investigate total lightning characteristics of extreme weather events over the contiguous United States (CONUS) using TRMM (Tropical Rainfall Measuring Mission) LIS (Lightning Image Sensor) and OTD (Optical Transient Detector) satellite observations. A large LIS (10+ years) and OTD (5 years) data base is available to study the instantaneous total or cloud-to-ground (CG) plus intracloud (IC)

L. D. Carey; W. A. Petersen; H. J. Christian

2008-01-01

103

Twisted Solar Active Region Magnetic Fields as Drivers of Space Weather: Observational  

E-print Network

Twisted Solar Active Region Magnetic Fields as Drivers of Space Weather: Observational and dynamics of magnetic fields on the Sun's photosphere and outer layers ­ notably those within solar active discuss here a novel technique for measuring twist in the magnetic field lines of solar active regions

Mackay, Duncan

104

Feasibility of using a seismic surface wave method to study seasonal and weather effects on shallow surface soils  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of the paper is to study the temporal variations of the subsurface soil properties due to seasonal and weather effects using a combination of a new seismic surface method and an existing acoustic probe system. A laser Doppler vibrometer (LDV) based multi-channel analysis of surface wav...

105

Weathering Animation  

NSDL National Science Digital Library

Weathering is the term that describes all the processes that break down rocks in the environment near the Earth's surface. This module will help you to understand two weathering processes: mechanical and chemical.

2002-01-01

106

Porosity and surface area evolution during weathering of two igneous rocks  

SciTech Connect

During weathering, rocks release nutrients and storewater vital for growth ofmicrobial and plant life. Thus, the growth of porosity as weathering advances into bedrock is a life-sustaining process for terrestrial ecosystems. Here, we use small-angle and ultra small-angle neutron scattering to show how porosity develops during initial weathering under tropical conditions of two igneous rock compositions, basaltic andesite and quartz diorite. The quartz diorite weathers spheroidally while the basaltic andesite does not. The weathering advance rates of the two systems also differ, perhaps due to this difference in mechanism, from 0.24 to 100 mm kyr1, respectively. The scattering data document how surfaces inside the feldspar-dominated rocks change as weathering advances into the protolith. In the unaltered rocks, neutrons scatter fromtwo types of featureswhose dimensions vary from6 nmto 40 lm: pores and bumps on pore grain surfaces. These features result in scattering data for both unaltered rocks that document multi-fractal behavior: scattering is best described by amass fractal dimension (Dm) and a surface fractal dimension (Ds) for features of length scales greater than and less than 1 lm, respectively. In the basaltic andesite, Dm is approximately 2.9 and Ds is approximately 2.7. The mechanism of solute transport during weathering of this rock is diffusion. Porosity and surface area increase from 1.5%to 8.5%and 3 to 23 m2 g1 respectively in a relatively consistent trend across themm-thick plagioclase reaction front. Across this front, both fractal dimensions decrease, consistentwith development of amoremonodisperse pore networkwith smoother pore surfaces. Both changes are consistent largely with increasing connectivity of pores without significant surface roughening, as expected for transport-limited weathering. In contrast, porosity and surface area increase from 1.3% to 9.5% and 1.5 to 13 m2 g1 respectively across a many cm-thick reaction front in the spheroidally weathering quartz diorite. In that rock, Dm is approximately 2.8 andDs is approximately 2.5 prior to weathering. These two fractals transform during weathering to multiple surface fractals as micro-cracking reduces the size of diffusion-limited subzones of thematrix.Across the reaction front of plagioclase in the quartz diorite, the specific surface area and porosity change very little until the pointwhere the rock disaggregates into saprolite. The different patterns in porosity development of the two rocks are attributed to advective infiltration plus diffusion in the rock that spheroidally fractures versus diffusion-only in the rock that does not. Fracturing apparently diminishes the size of the diffusion-limited parts of the spheroidally weathering rock system to promote infiltration of meteoric fluids, thereforeexplaining the faster weathering advance rate into that rock.

Navarre-Sitchler, Alexis [Colorado School of Mines, Golden; Cole, David [Ohio State University; Rother, Gernot [ORNL; Jin, Lixin [University of Texas, El Paso; Buss, Heather [University of Bristol, UK; Brantley, S. L. [Pennsylvania State University, University Park, PA

2013-01-01

107

Evolution of Stratocumulus Over Land: Comparison of Ground and Aircraft Observations with Numerical Weather Prediction Simulations  

NASA Astrophysics Data System (ADS)

Forecasting of low cloud continues to challenge numerical weather prediction. With this in mind, surface and airborne observations were made over East Anglia, UK, during March 2011 to investigate stratus and stratocumulus advecting from the sea over land. Four surface sites were deployed at various distances inland aligned approximately along the flow. In situ data include cloud-droplet measurements from an aircraft operating off the coast and a tethered balloon 100 km inland. Comparisons of thermodynamic and cloud properties are made with Met Office operational model simulations at horizontal resolutions of 4 and 1.5 km. The clouds contained droplet concentrations up to 600 cm^{-3} within polluted outflow off Europe. These measurements were compared to three different model schemes for predicting droplet concentration: two of them perform well at low to moderate concentrations but asymptote to 375 cm^{-3} . Microwave radiometers at the ground sites retrieved liquid water paths that reduced with distance inland and were generally below 200 g m^{-2} . The modelled water path performs well upstream but more erratically far inland. Comparisons of thermodynamic profiles are made within both Lagrangian and Eulerian frameworks and show the model predicted changes in equivalent potential temperature generally within 1 K, with occasional errors of 2 K or more. The modelled cloud-top temperatures were in good agreement with the observations down to - 7° C, but the magnitude of the temperature inversion, although good at times, was too small by on average 1.6 K. The different simulations produced different cloud-top water contents due to a combination of resolution and scientific upgrades to the model, but they generally underestimate the amount of cloud water. Major changes, such as the mesoscale temporary cloud breaks on 2 March 2011 and the complete clearance on 4 March, were seemingly predicted by the model for the correct reasons.

Osborne, Simon R.; Abel, Steven J.; Boutle, Ian A.; Marenco, Franco

2014-07-01

108

Changes in the weathering of rock surfaces in different geomorphological environments: glacial, nival and coastal.  

NASA Astrophysics Data System (ADS)

The sclerometer or Schmidt Rock Test Hammer has been broadly applied in geomorphology to estimate the strength of different rock types and to measure the degree of rock weathering. It has been proved that for a rock type, the rebound values are lower in weathered than in fresh rock surfaces. This evidence suggests that if there is any factor that causes a gradual change in the weathering degree, it must be possible to identify a distinctive tendency with the sclerometer. There are two types of factors that can cause gradual changes in the weathering degree. First, those related with the time of exposure of a rock surface, which are the basis of works that attempt to use the sclerometer as a tool for relative chronology. Second, those related with the frequency or duration at which the weathering agents operate, which are the basis for the studies focused on the efficacy of weathering. In both cases it is essential to understand how the factors of weathering are spatially distributed in order to achieve a good sampling procedure. We applied the sclerometer in three different environments: rock coasts, glacially exposed surfaces and rock surfaces subjected to nival processes. The sclerometer was used in a receding glacier in Tierra de Fuego, Argentina, assuming that the rock surface must be more weathered as more time passed since the exposure. The hypothesis was confirmed by the negative correlation between rebound values and the distance to the glaciar front. In rocky coasts, it was proved by field and laboratory data that one of the main factors responsible for variations in rock strength is the degree of weathering by tidally-induced wetting and drying. We found negative correlations between rebound values and tidal elevation in very different coastal environments in the NW of Spain and in the Beagle Channel. We also found that the absence of this relationship may be caused by processes of mechanical erosion, but they also can respond to disequilibrium of the intertidal surfaces with tidal range. The research on nival processes was conducted in an ancient glacial cirque in the western mountains of Galicia (NW Spain). The hypothesis here was that weathering degree of rock surface is related with the abrasion produced when a late-lying snow cover slides in the spring. The frequency and extent to which abrasion and other erosional processes take place depends mainly on the thickness of the snow accumulated in a rock wall. Therefore, the rock surfaces are more weathered as frequency and intensity of abrasion decreases with the distance to the rock wall. The experience in three different types of environment suggests that when the sclerometer is used to measure the weathering degree, the sampling method arises as one of the most important factors. The distribution of the sampling points must respond to the characteristics of each area, which needs a previous understanding of the processes and factors responsible of the variations in the degree of weathering. Aknowledgements This work was supported by the research projects GL2004-3380/BOS (Ministerio de Educación y Ciencia) and PGIDIT06PXIB239226PR and PGDIT05PXIC21001PN (Xunta de Galicia). A. Feal Pérez is supported by the grant AP2006-03854

Feal-Pérez, A.; Blanco-Chao, R.; Pérez-Alberti, A.; López-Bedoya, J.; Valcárcel-Díaz, M.

2009-04-01

109

Conversion of bedrock to soil and feedback processes between the surface and the weathering front in a deeply weathered regolith, Central Sri Lankan Highlands  

NASA Astrophysics Data System (ADS)

In the Sri Lankan highlands denudation rates and chemical weathering rates represent the low-end-member in global weathering rates [1, 2]. Here we explore the causes for these low rates by a detailed soil-mineralogical study of a highly weathered deep saprolite profile developed from charnockite bedrock. Spheroidal weathering of the bedrock characterized the weathering front where rounded corestones are produced at the rock-saprolite interface. The first mineral attacked by weathering was found to be pyroxene but plagioclase is the first mineral depleted to near-completion at the corestone-saprolite-boundary. Weathering of pyroxene is initiated by in situ iron oxidation, leading to an increase of porosity due to micro-cracking [3]. The accrued micro cracks allow for fluid transport and the dissolution of biotite and plagioclase. The strong plagioclase weathering leads to formation of high secondary porosity over a small distance and the final disaggregation of bedrock to saprolite. Sequential extraction showed that the first secondary phases are amorphous oxides from which secondary minerals (gibbsite, kaolinite, goethite and minor amounts of smectites) precipitate. Modeling of the strain formation due to increasing volume during iron oxidation in pyroxene and biotite showed that spheroidal weathering can be explained with this process only if the formation of secondary porosity, due to a negative volume budget during primary mineral weathering to secondary phases, occurs. As oxidation is the first occurring reaction, O2 is a rate limiting factor for chemical weathering in this setting. Hence the supply of oxygen and the consumption at depth connects processes at the weathering front with those at the surface as a feedback mechanism. Advective and diffusive transport modeling shows that the feedback will be much more pronounced with dominating diffusive transport. Due to the low porosity of the bedrock the O2 transport in the pristine bedrock occurs via diffusion. The slow weathering rate is, beside tectonic quiescence, related to this feedback and to lithological factors such as low porosity and the amount of Fe-bearing primary minerals. 1. Hewawasam, T., et al., Slow advance of the weathering front during deep, supply-limited saprolite formation in the tropical Highlands of Sri Lanka. Geochimica et Cosmochimica Acta, 2013. 118: p. 202-230. 2. von Blanckenburg, F., T. Hewawasam, and P. Kubik, Cosmogenic nuclide evidence for low weathering and denudation in the wet tropical Highlands of Sri Lanka. J. Geoph. Res., 2004. 109: p. doi10.1029/2003JF000049. 3. Buss, H.L., et al., Weathering of the Rio Blanco quartz diorite, Luquillo Mountains, Puerto Rico: Coupling oxidation, dissolution, and fracturing. Geochimica et Cosmochimica Acta, 2008. 72(18): p. 4488-4507.

Behrens, Ricarda; Bouchez, Julien; Schuessler, Jan A.; Dultz, Stefan; Hewawasam, Tilak; von Blanckenburg, Friedhelm

2014-05-01

110

Draft Genome Sequence of Rhizobium sp. H41, a Rock-Weathering Bacterium from a Weathered Rock Surface.  

PubMed

Rhizobium sp. H41 isolated from weathered tuff can weather tuff and release Fe, Si, and Al from the rock under nutrient-poor conditions. Here, we report the draft genome sequence of strain H41, which may facilitate a better understanding of the molecular mechanism involved in rock weathering by the bacterium. PMID:25377707

Xi, Jun; Sheng, Xiafang; He, Linyan

2014-01-01

111

Draft Genome Sequence of Rhizobium sp. H41, a Rock-Weathering Bacterium from a Weathered Rock Surface  

PubMed Central

Rhizobium sp. H41 isolated from weathered tuff can weather tuff and release Fe, Si, and Al from the rock under nutrient-poor conditions. Here, we report the draft genome sequence of strain H41, which may facilitate a better understanding of the molecular mechanism involved in rock weathering by the bacterium. PMID:25377707

Xi, Jun; He, Linyan

2014-01-01

112

How to Use the Weather Program  

NSDL National Science Digital Library

This undergraduate meteorology tutorial introduces The Weather Program, available from NCAR (the National Center for Atmospheric Research). The Weather program obtains weather data for requested stations and times. This tutorial provides students with experience with the interfaces, Netscape and a shell window. Students learn to access surface observations both decoded and raw and National Weather Service forecasts, watches and warnings. They learn to determine where warnings are active and to find specific requested weather information.

Nielsen-Gammon, John

1996-01-01

113

Hubble Observes Surface of Titan  

NASA Technical Reports Server (NTRS)

Scientists for the first time have made images of the surface of Saturn's giant, haze-shrouded moon, Titan. They mapped light and dark features over the surface of the satellite during nearly a complete 16-day rotation. One prominent bright area they discovered is a surface feature 2,500 miles across, about the size of the continent of Australia.

Titan, larger than Mercury and slightly smaller than Mars, is the only body in the solar system, other than Earth, that may have oceans and rainfall on its surface, albeit oceans and rain of ethane-methane rather than water. Scientists suspect that Titan's present environment -- although colder than minus 289 degrees Fahrenheit, so cold that water ice would be as hard as granite -- might be similar to that on Earth billions of years ago, before life began pumping oxygen into the atmosphere.

Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory and his team took the images with the Hubble Space Telescope during 14 observing runs between Oct. 4 - 18. Smith announced the team's first results last week at the 26th annual meeting of the American Astronomical Society Division for Planetary Sciences in Bethesda, Md. Co-investigators on the team are Mark Lemmon, a doctoral candidate with the UA Lunar and Planetary Laboratory; John Caldwell of York University, Canada; Larry Sromovsky of the University of Wisconsin; and Michael Allison of the Goddard Institute for Space Studies, New York City.

Titan's atmosphere, about four times as dense as Earth's atmosphere, is primarily nitrogen laced with such poisonous substances as methane and ethane. This thick, orange, hydrocarbon haze was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The haze is formed as methane in the atmosphere is destroyed by sunlight. The hydrocarbons produced by this methane destruction form a smog similar to that found over large cities, but is much thicker.

Smith's group used the Hubble Space Telescope's WideField/Planetary Camera 2 at near-infrared wavelengths (between .85 and 1.05 microns). Titan's haze is transparent enough in this wavelength range to allow mapping of surface features according to their reflectivity. Only Titan's polar regions could not be mapped this way, due to the telescope's viewing angle of the poles and the thick haze near the edge of the disk. Their image-resolution (that is, the smallest distance seen in detail) with the WFPC2 at the near-infrared wavelength is 360 miles. The 14 images processed and compiled into the Titan surface map were as 'noise' free, or as free of signal interference, as the space telescope allows, Smith said.

Titan makes one complete orbit around Saturn in 16 days, roughly the duration of the imaging project. Scientists have suspected that Titan's rotation also takes 16 days, so that the same hemisphere of Titan always faces Saturn, just as the same hemisphere of the Earth's moon always faces the Earth. Recent observations by Lemmon and colleagues at the University of Arizona confirm this true.

It's too soon to conclude much about what the dark and bright areas in the Hubble Space Telescope images are -- continents, oceans, impact craters or other features, Smith said. Scientists have long suspected that Titan's surface was covered with a global ehtane-methane ocean. The new images show that there is at least some solid surface.

Smith's team made a total 50 images of Titan last month in their program, a project to search for small scale features in Titan's lower atmosphere and surface. They have yet to analyze images for information about Titan's clouds and winds. That analysis could help explain if the bright areas are major impact craters in the frozen water ice-and-rock or higher-altitude features.

The images are important information for the Cassini mission, which is to launch a robotic spacecraft on a 7-year journey to Saturn in October 1997. About three weeks before Cassini's first flyby

1994-01-01

114

The Main Pillar: Assessment of Space Weather Observational Asset Performance Supporting Nowcasting, Forecasting and Research to Operations  

NASA Astrophysics Data System (ADS)

Sporadically, the Sun unleashes severe magnetic activity into the heliosphere. The specific solar/heliospheric phenomena and their effects on humans, technology and the wider geospace environment include a) high-intensity emissions from the Sun causing radio blackouts and (surface) charging, b) particle acceleration in the solar corona leading to high dose rates of ionizing radiation in exposed materials that can trigger single event upsets in electronic components of space hardware, or temporal/permanent damage in tissue, c) arrivals of fast-moving coronal mass ejections with embedded enhancements of magnetic fields that can cause strong ionospheric disturbances affecting radio communications and induce out-of-spec currents in power lines near the surface. Many of the effects could now be forecast with higher fidelity than ever before. However, forecasting critically depends upon availability of timely and reliable observational data. It is therefore crucial to understand how observational assets perform during periods of severe space weather. This paper analyzes and documents the status of the existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations.

Posner, A.; Hesse, M.; St. Cyr, C.

2012-12-01

115

Developing a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface  

E-print Network

Developing a TeraGrid Based Land Surface Hydrology and Weather Modeling Interface Hsin-I Chang1 iclimate@purdue.edu -------------------- -------------------- 1 INTRODUCTION Real world hydrologic cyberinfrastructure (CI) has been articulated in many workshops and meetings of the environmental and hydrologic

Jiang, Wen

116

Total Lightning Observations of Extreme Weather Events over the Contiguous United States  

NASA Astrophysics Data System (ADS)

The overall objective is to investigate total lightning characteristics of extreme weather events over the contiguous United States (CONUS) using TRMM (Tropical Rainfall Measuring Mission) LIS (Lightning Image Sensor) and OTD (Optical Transient Detector) satellite observations. A large LIS (10+ years) and OTD (5 years) data base is available to study the instantaneous total or cloud-to-ground (CG) plus intracloud (IC) lightning characteristics of extreme weather events. More specifically, the LIS and OTD data are combined with National Lightning Detection Network (NLDN) observations to examine the total and CG lightning flash rate and density, the IC:CG ratio, and positive CG percentage. These instantaneous lightning characteristics can be used for basic science studies to better understand the physical and dynamical linkages between lightning and precipitation and their environmental controls. They can also provide a first-look of extreme weather events leading up to future satellite observations (e.g., NOAA GOES-R Geostationary Lightning Mapper [GLM]) for use in climate studies and the short-term prediction and warning process. Extreme weather events are defined by the NOAA Storm Data reports of tornadoes, large hail (at least 0.75 inch) and strong straight-line winds (at least 50 kts). Over CONUS, there are over 70,000 severe storm reports in the TRMM spatial domain (< 35 degrees N) from 1998-2007 and over 100,000 storm reports in the OTD spatial domain (5/1995-4/2000). Temporal co-location is on the order of 1% (i.e., 1000's of coincident overpasses), providing a statistically significant sample of instantaneous total lightning properties. This instantaneous behavior of lightning in extreme weather is then compared to that of typical thunderstorm events, or randomly sampled LIS/OTD events in which the extreme events have been eliminated from the population. Results describing the instantaneous behavior of total lightning within a large sample of extreme and typical thunderstorms over CONUS will be presented. When possible, coincident VHF lightning observations from the ground-based Northern Alabama Lightning Mapping Array (LMA) are compared to the LIS/OTD optical lightning signatures, providing a validation source for instantaneous space-based optical lightning properties and a means to extend lightning inferences over the life-cycle of extreme weather.

Carey, L. D.; Petersen, W. A.; Christian, H. J.

2008-12-01

117

Real-Time Detection of Small Surface Objects Using Weather Effects  

Microsoft Academic Search

\\u000a Small surface objects, usually containing important information, are difficult to be identified under realistic atmospheric\\u000a conditions because of weather degraded image features. This paper describes a novel algorithm to overcome the problem, using\\u000a depth-aware analysis. Because objects-participating local patches always contain low intensities in at least one color channel,\\u000a we detect suspicious small surface objects using the dark channel prior.

Baojun Qi; Tao Wu; Hangen He; Tingbo Hu

2010-01-01

118

Cockpit weather information needs  

NASA Technical Reports Server (NTRS)

The primary objective is to develop an advanced pilot weather interface for the flight deck and to measure its utilization and effectiveness in pilot reroute decision processes, weather situation awareness, and weather monitoring. Identical graphical weather displays for the dispatcher, air traffic control (ATC), and pilot crew should also enhance the dialogue capabilities for reroute decisions. By utilizing a broadcast data link for surface observations, forecasts, radar summaries, lightning strikes, and weather alerts, onboard weather computing facilities construct graphical displays, historical weather displays, color textual displays, and other tools to assist the pilot crew. Since the weather data is continually being received and stored by the airborne system, the pilot crew has instantaneous access to the latest information. This information is color coded to distinguish degrees of category for surface observations, ceiling and visibilities, and ground radar summaries. Automatic weather monitoring and pilot crew alerting is accomplished by the airborne computing facilities. When a new weather information is received, the displays are instantaneously changed to reflect the new information. Also, when a new surface or special observation for the intended destination is received, the pilot crew is informed so that information can be studied at the pilot's discretion. The pilot crew is also immediately alerted when a severe weather notice, AIRMET or SIGMET, is received. The cockpit weather display shares a multicolor eight inch cathode ray tube and overlaid touch panel with a pilot crew data link interface. Touch sensitive buttons and areas are used for pilot selection of graphical and data link displays. Time critical ATC messages are presented in a small window that overlays other displays so that immediate pilot alerting and action can be taken. Predeparture and reroute clearances are displayed on the graphical weather system so pilot review of weather along the route can be accomplished prior to pilot acceptance of the clearance. An ongoing multiphase test series is planned for testing and modifying the graphical weather system. Preliminary data shows that the nine test subjects considered the graphical presentation to be much better than their current weather information source for situation awareness, flight safety, and reroute decision making.

Scanlon, Charles H.

1992-01-01

119

Modelling convective severe weather occurrence using observations, reanalysis data and decadal climate predictions  

NASA Astrophysics Data System (ADS)

Observations of local severe convective events can be combined with atmospheric reanalyses to compute severe weather probability as a function of parameters characterizing the local state of the atmosphere. Using ERA-Interim reanalysis data and observations from the European Severe Weather Database, we have investigated several ways to express the probability of large hail, tornadoes, flash floods or wind gusts as a function of parameters such as convective available potential energy, vertical wind shear and precipitation. Our attempts include fitting analytic functions, using smoothers of various kinds, and binning the data within the multidimensional parameter space according to various algorithms. We imposed that any difference between binned observations and the modelled probability function be insignificant at the 95% confidence level. Further tests of robustness of the model were conducted. A probability function fulfilling this criterion was selected and subsequently applied to the ERA-Interim data as well as to predictions of the decadal forecasting system developed in the MiKlip programme. We investigated climatic and modelled past and future trends of severe convective weather. We will present the (preliminary) results of that effort.

Pistotnik, Georg; Groenemeijer, Pieter

2014-05-01

120

Combining solar science and asteroid science with the space weather observation network (SWON)  

NASA Astrophysics Data System (ADS)

The peculiarity of space weather for Earth orbiting satellites, air traffic and power grids on Earth and especially the financial and operational risks posed by damage due to space weather, underline the necessity of space weather observation. The importance of such observations is even more increasing due to the impending solar maximum. In recognition of this importance we propose a mission architecture for solar observation as an alternative to already published mission plans like Solar Probe (NASA) or Solar Orbiter (ESA). Based upon a Concurrent Evaluation session in the Concurrent Engineering Facility of the German Aerospace Center, we suggest using several spacecraft in an observation network. Instead of placing such spacecraft in a solar orbit, we propose landing on several asteroids, which are in opposition to Earth during the course of the mission and thus allow observation of the Sun's far side. Observation of the far side is especially advantageous as it improves the warning time with regard to solar events by about 2 weeks. Landing on Inner Earth Object (IEO) asteroids for observation of the Sun has several benefits over traditional mission architectures. Exploiting shadowing effects of the asteroids reduces thermal stress on the spacecraft, while it is possible to approach the Sun closer than with an orbiter. The closeness to the Sun improves observation quality and solar power generation, which is intended to be achieved with a solar dynamic system. Furthermore landers can execute experiments and measurements with regard to asteroid science, further increasing the scientific output of such a mission. Placing the spacecraft in a network would also benefit the communication contact times of the network and Earth. Concluding we present a first draft of a spacecraft layout, mission objectives and requirements as well as an initial mission analysis calculation.

Maiwald, Volker; Weiß, André; Jansen, Frank

2012-12-01

121

Mars surface weathering products and spectral analogs: Palagonites and synthetic iron minerals  

NASA Technical Reports Server (NTRS)

There are several hypotheses regarding the formation of Martian surface fines. These surface fines are thought to be products of weathering processes occurring on Mars. Four major weathering environments of igneous rocks on Mars have been proposed; (1) impact induced hydrothermal alterations; (2) subpermafrost igneous intrusion; (3) solid-gas surface reactions; and (4) subaerial igneous intrusion over permafrost. Although one or more of these processes may be important on the Martian surface, one factor in common for all these processes is the reaction of solid or molten basalt with water (solid, liquid, or gas). These proposed processes, with the exception of solid-gas surface reactions, are transient processes. The most likely product of transient hydrothermal processes are layer silicates, zeolites, hydrous iron oxides and palagonites. The long-term instability of hydrous clay minerals under present Martian conditions has been predicted; however, the persistence of such minerals due to slow kinetics of dehydration, or entrapment in permafrost, where the activity of water is high, can not be excluded. Anhydrous oxides of iron (e.g., hematite and maghemite) are thought to be stable under present Martian surface conditions. Oxidative weathering of sulfide minerals associated with Martian basalts has been proposed. Weathering of sulfide minerals leads to a potentially acidic permafrost and the formation of Fe(3) oxides and sulfates. Weathering of basalts under acidic conditions may lead to the formation of kaolinite through metastable halloysite and metahalloysite. Kaolinite, if present, is thought to be a thermodynamically stable phase at the Martian surface. Fine materials on Mars are important in that they influence the surface spectral properties; these fines are globally distributed on Mars by the dust storms and this fraction will have the highest surface area which should act as a sink for most of the absorbed volatiles near the surface of Mars. Therefore, the objectives of this study were to: (1) examine the fine fraction mineralogy of several palagonitic materials from Hawaii; and (2) compare spectral properties of palagonites and submicron sized synthetic iron oxides with the spectral properties of the Martian surface.

Golden, D. C.; Ming, D. W.; Morris, R. V.; Lauer, H. V., Jr.

1992-01-01

122

Effects of UV weathering on surface properties of polypropylene composites reinforced with wood flour, lignin, and cellulose  

NASA Astrophysics Data System (ADS)

In this study, the influence of accelerated weathering on polypropylene composites reinforced with wood flour (WF), lignin, and cellulose at different loading levels were evaluated. Six groups of samples were exposed in a QUV accelerated weathering tester for a total of 960 h. The surface color, surface gloss, contact angle and flexural properties of the samples were tested. Besides, the weathered surface was characterized by SEM and ATR-FTIR. The results revealed that (1) the discoloration of composites was accelerated by the presence of lignin, especially at high content; (2) composites containing lignin showed less loss of flexural strength and modulus, less cracks, and better hydrophobicity on weathered surface than other groups, confirming its functions of stabilization and antioxidation; (3) cellulose-based composites exhibited better color stability but more significant deterioration in flexural properties after weathering compared to other composites, suggesting that such kind of composites could not be used as load-bearing structure in outdoor applications.

Peng, Yao; Liu, Ru; Cao, Jinzhen; Chen, Yu

2014-10-01

123

Low Cloud Type over the Ocean from Surface Observations. Part I: Relationship to Surface Meteorology and the Vertical Distribution of Temperature and Moisture  

Microsoft Academic Search

Surface cloud observations and coincident surface meteorological observations and soundings from five ocean weather stations are used to establish representative relationships between low cloud type and marine boundary layer (MBL) properties for the subtropics and midlatitudes by compositing soundings and meteorological ob- servations for which the same low cloud type was observed. Physically consistent relationships are found to exist between

Joel R. Norris

1998-01-01

124

WORLD SURFACE CURRENTS FROM SHIP'S DRIFT OBSERVATIONS  

SciTech Connect

Over 4 million observations of ship's drift are on file at the U.S. National Oceanographic Data Centre, in Washington, D. C., representing a vast amount of information on ocean surface currents. The observed drift speeds are dependent on the frequency of occurence of the particular current speeds and the frequency of observation. By comparing frequency of observation with the drift speeds observed it is possible to confirm known current patterns and detect singularities in surface currents.

Duncan, C.P.; Schladow, S.G.

1980-11-01

125

A High-Resolution 3D Weather Radar, MSG, and Lightning Sensor Observation Composite  

NASA Astrophysics Data System (ADS)

Within the research group 'Object-based Analysis and SEamless prediction' (OASE) of the Hans Ertel Centre for Weather Research programme (HerZ), a data composite containing weather radar, lightning sensor, and Meteosat Second Generation observations is being developed for the use in object-based weather analysis and nowcasting. At present, a 3D merging scheme combines measurements of the Bonn and Jülich dual polarimetric weather radar systems (data provided by the TR32 and TERENO projects) into a 3-dimensional polar-stereographic volume grid, with 500 meters horizontal, and 250 meters vertical resolution. The merging takes into account and compensates for various observational error sources, such as attenuation through hydrometeors, beam blockage through topography and buildings, minimum detectable signal as a function of noise threshold, non-hydrometeor echos like insects, and interference from other radar systems. In addition to this, the effect of convection during the radar 5-minute volume scan pattern is mitigated through calculation of advection vectors from subsequent scans and their use for advection correction when projecting the measurements into space for any desired timestamp. The Meteosat Second Generation rapid scan service provides a scan in 12 spectral visual and infrared wavelengths every 5 minutes over Germany and Europe. These scans, together with the derived microphysical cloud parameters, are projected into the same polar stereographic grid used for the radar data. Lightning counts from the LINET lightning sensor network are also provided for every 2D grid pixel. The combined 3D radar and 2D MSG/LINET data is stored in a fully documented netCDF file for every 5 minute interval, and is made ready for tracking and object based weather analysis. At the moment, the 3D data only covers the Bonn and Jülich area, but the algorithms are planed to be adapted to the newly conceived DWD polarimetric C-Band 5 minute interval volume scan strategy. An extension of the 3D composite to all of Germany is therefore possible and set as a goal.

Diederich, Malte; Senf, Fabian; Wapler, Kathrin; Simmer, Clemens

2013-04-01

126

Weather effects on the aerosol characteristics in the surface layer of the atmosphere  

Microsoft Academic Search

On the basis of 14-year (1994–2007) series of the semi-annual (January to June) measurements of the atmospheric aerosol microstructure\\u000a in Dolgoprudny, Moscow region, effects are analyzed of pressure, wind speed, precipitation, and surface temperature inversions\\u000a on the aerosol particle concentration. It is shown that the weather parameters affect concentration of the particles within\\u000a a certain range of sizes (0.1 to

E. A. Stulov; N. O. Plaude; I. A. Monakhova

2010-01-01

127

Data Assimilation of SMAP Observations and the Impact on Weather Forecasts and Heat Stress  

NASA Technical Reports Server (NTRS)

SPoRT produces real-time LIS soil moisture products for situational awareness and local numerical weather prediction over CONUS, Mesoamerica, and East Africa ?Currently interact/collaborate with operational partners on evaluation of soil moisture products ?Drought/fire ?Extreme heat ?Convective initiation ?Flood and water borne diseases ?Initial efforts to assimilate L2 soil moisture observations from SMOS (as a precursor for SMAP) have been successful ?Active/passive blended product from SMAP will be assimilated similarly and higher spatial resolution should improve on local-scale processes

Zavodsky, Bradley; Case, Jonathan; Blankenship, Clay; Crosson, William; White, Khristopher

2014-01-01

128

State of Art in space weather observational activities and data management in Europe  

NASA Astrophysics Data System (ADS)

One of the primary scientific and technical goals of space weather is to produce data in order to investigate the Sun impact on the Earth and its environment. Studies based on data mining philosophy yield increase the knowledge of space weather physical properties, modelling capabilities and gain applications of various procedures in space weather monitoring and forecasting. Exchanging tailored individually and/or jointly data between different entities, storing of the databases and making data accessible for the users is the most important task undertaken by investigators. National activities spread over Europe is currently consolidated pursuant to the terms of effectiveness and individual contributions embedded in joint integrated efforts. The role of COST 724 Action in animation of such a movement is essential. The paper focuses on the analysis of the European availability in the Internet near-real time and historical collections of the European ground based and satellite observations, operational indices and parameters. A detailed description of data delivered is included. The structure of the content is supplied according to the following selection: (1) observations, raw and/or corrected, updated data, (2) resolution, availability of real-time and historical data, (3) products, as the results of models and theory including (a) maps, forecasts and alerts, (b) resolution, availability of real-time and historical data, (4) platforms to deliver data. Characterization of the networking of stations, observatories and space related monitoring systems of data collections is integrated part of the paper. According to these provisions operational systems developed for these purposes is presented and analysed. It concerns measurements, observations and parameters from the theory and models referred to local, regional collections, European and worldwide networks. Techniques used by these organizations to generate the digital content are identified. As the reference pan-European and some national data centres and bases are described and compared with currently available data information provided worldwide and by relevant entities outside Europe. Current, follow up and expected future European space weather observational activities and data management perspectives in respect to European main lines of policy is the subject of the conclusions.

Stanislawska, Iwona

129

Space Weather Observations by GNSS Radio Occultation: From FORMOSAT-3/COSMIC to FORMOSAT-7/COSMIC-2  

NASA Astrophysics Data System (ADS)

joint Taiwan-United States FORMOSAT-3/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) mission, hereafter called COSMIC, is the first satellite constellation dedicated to remotely sense Earth's atmosphere and ionosphere using a technique called Global Positioning System (GPS) radio occultation (RO). The occultations yield abundant information about neutral atmospheric temperature and moisture as well as space weather estimates of slant total electron content, electron density profiles, and an amplitude scintillation index, S4. With the success of COSMIC, the United States and Taiwan are moving forward with a follow-on RO mission named FORMOSAT-7/COSMIC-2 (COSMIC-2), which will ultimately place 12 satellites in orbit with two launches in 2016 and 2019. COSMIC-2 satellites will carry an advanced Global Navigation Satellite System (GNSS) RO receiver that will track both GPS and Russian Global Navigation Satellite System signals, with capability for eventually tracking other GNSS signals from the Chinese BeiDou and European Galileo system, as well as secondary space weather payloads to measure low-latitude plasma drifts and scintillation at multiple frequencies. COSMIC-2 will provide 4-6 times (10-15X in the low latitudes) the number of atmospheric and ionospheric observations that were tracked with COSMIC and will also improve the quality of the observations. In this article we focus on COSMIC/COSMIC-2 measurements of key ionospheric parameters.

Yue, Xinan; Schreiner, William S.; Pedatella, Nicholas; Anthes, Richard A.; Mannucci, Anthony J.; Straus, Paul R.; Liu, Jann-Yenq

2014-11-01

130

Widespread surface weathering on early Mars: A case for a warmer and wetter climate  

NASA Astrophysics Data System (ADS)

Early Mars (>3 Ga) underwent aqueous alteration as evidenced by fluvial/lacustrine morphologies and the recent discovery of widespread hydrous clays. Despite compelling evidence for diverse and localized aqueous environments, the possibility for sustained liquid water globally on the martian surface and over geological timescales is still highly debated. Instead, a durably cold and dry Mars scenario is often proposed. By studying specific Fe/Mg and Al-rich clay stratigraphies on Mars by means of a planetary scale orbital investigation, we present new evidence that Mars experienced an early era (>3.7 Ga) of widespread aqueous alteration consistent with surface weathering.

Carter, John; Loizeau, Damien; Mangold, Nicolas; Poulet, François; Bibring, Jean-Pierre

2015-03-01

131

A much warmer Earth surface for most of geologic time: implications to biotic weathering  

NASA Technical Reports Server (NTRS)

The authors present two scenarios for the temperature history of Earth. One scenario is conventional, the other relies on a warmer history. Both scenarios include surface cooling determined by the evolution of the biosphere and are similar until the Proterozoic period. The warmer scenario requires a higher plant/lichen terrestrial biota to increase weathering intensity. Justification for a warmer surface includes period temperatures from the oxygen isotope record of coexisting phosphates and cherts, an upper limit of 58 degrees C from primary gypsum precipitation, and the lack of fractionation of sulfur isotopes between sulfide and sulfates in Archean sediments.

Schwartzman, D. W.; McMenamin, M.

1993-01-01

132

Observation targeting for numerical weather prediction: the impact of different observation types in dynamically sensitive regions.  

NASA Astrophysics Data System (ADS)

Experiences with real-time observation targeting have shown that an optimal flow-dependent deployment of in situ observations promise significant improvements in forecasts skill. In the near future, in addition to the large quantity of data provided by advanced multispectral IR sounders, new flexible in situ observing platforms will increase the possible targeted data coverage over oceans. The need for in situ soundings in sensitive areas depends highly on the limitations, to be assessed, of cloud cover on the remote IR sounding data. New adjoint based techniques for observation targeting have been developped both at ECMWF and Météo-France. Those approaches allow an estimation of the reduction of forecast error variance due to the assimilation of an additional set of observations. The variance reductions due to possible sets are then compared, for a given fixed distribution of background errors. These predicted reductions of variance have to be validated with actual realizations of the reduction of the forecast error in a series of analysis/forecast experiments. A first step towards validation is provided by idealized analysis/forecast experiments using simulated observations. The results of such experiments will be presented. In particular, the impact of using targeted in situ observations sets and/or satellite IR soundings, assuming realistic cloud cover, are compared within such an experimental setting.

Doerenbecher, A.; Leutbecher, M.

2003-04-01

133

Surface-Correlated Nanophase Iron Metal in Lunar Soils: Petrography and Space Weathering Effects  

NASA Technical Reports Server (NTRS)

Space weathering is a term used to include all of the processes that act on material exposed at the surface of a planetary or small body. In the case of the Moon, it includes a variety of processes that formed the lunar regolith, caused the maturation of lunar soils, and formed patina on rock surfaces. The processes include micrometeorite impact and reworking, implantation of solar wind and flare particles, radiation damage and chemical effects from solar particles and cosmic rays, interactions with the lunar atmosphere, and sputtering erosion and deposition. Space weathering effects collectively result in a reddened continuum slope, lowered albedo, and attenuated absorption features in reflectance spectra of lunar soils as compared to finely comminuted rocks from the same Apollo sites. Understanding these effects is critical in order to fully integrate the lunar sample collection with remotely sensed data from recent robotic missions (e.g., Lunar Prospector, Clementine, Galileo). Our objective is to determine the origin of space weathering effects in lunar soils through combined electron microscopy and microspectrophotometry techniques applied to individual soil particles from <20 pm size factions (dry-sieved) of mature lunar soils. It has been demonstrated that it is the finest size fraction (<25 pm) of lunar soils that dominates the optical properties of the bulk soils.

Keller, Lindsay P.; Wentworth, Susan J.; McKay, David S.

1998-01-01

134

Satellite Based Mapping of Land Surface ET using MODIS and Alternate Surface Meteorological Inputs from AMSR-E, Reanalysis, and Surface Weather Stations  

NASA Astrophysics Data System (ADS)

Regional evapotranspiration (ET), including water loss from plant transpiration and soil evaporation, is essential to understanding interactions between land-atmosphere surface energy and water balances. Vapor pressure deficit (VPD) and surface air temperature are key variables for stomatal conductance and ET estimation. We developed an algorithm to estimate ET using a modified Penman-Monteith approach driven by MODIS derived vegetation data and daily surface meteorological inputs including net incoming solar radiation, air temperature and VPD. The model was applied using alternate daily meteorological inputs, including: 1) site level weather station observations, 2) VPD and air temperature derived from the Advanced Microwave Scanning Radiometer (AMSR-E) on the EOS Aqua satellite, and 3) Global Modeling and Assimilation Office (GMAO) reanalysis based surface temperature, humidity and solar radiation data. Model performance was assessed across a North American boreal-Arctic transect (>50o N) of six eddy covariance flux towers representing boreal grassland, boreal forest and tundra biomes. Model results derived from the three meteorology data sets agree well with observed tower fluxes (r>0.6; P<0.00001; RMSE<30W/m2) and capture spatial patterns and seasonal variability in ET. The MODIS-AMSR-E derived ET results also show comparable accuracy to ET results derived from the reanalysis meteorology, while ET estimation error was generally more a function of algorithm parameterization than differences in meteorology drivers. Our results indicate significant potential for regional mapping and monitoring daily land surface evaporation using synergistic information from satellite optical-IR and microwave remote sensing.

Mu, Q.; Jones, L. A.; Kimball, J. S.; Running, S. W.

2007-12-01

135

Modeling COSMO-SkyMed measurements of precipitating clouds over the sea using simultaneous weather radar observations  

NASA Astrophysics Data System (ADS)

Several satellite missions employing X-band synthetic aperture radar (SAR) have been activated to provide high-resolution images of normalized radar cross-sections (NRCS) on land and ocean for numerous applications. Rainfall and wind affect the sea surface roughness and consequently the NRCS from the combined effects of corrugation due to impinging raindrops and surface wind. X-band frequencies are sensitive to precipitation: intense convective cells result in irregularly bright and dark patches in SAR images, masking changes in surface NRCS. Several works have modeled SAR images of intense precipitation over land; less adequately investigated is the precipitation effect over the sea surface. These images are analyzed in this study by modeling both the scattering and attenuation of radiation by hydrometeors in the rain cells and the NRCS surface changes using weather radar precipitation estimates as input. The reconstruction of X-band SAR returns in precipitating clouds is obtained by the joint utilization of volume reflectivity and attenuation, the latter estimated by coupling ground-based radar measurements and an electromagnetic model to predict the sea surface NRCS. Radar signatures of rain cells were investigated using X-band SAR images collected from the COSMO-SkyMed constellation of the Italian Space Agency. Two case studies were analyzed. The first occurred over the sea off the coast of Louisiana (USA) in summer 2010 with COSMO-SkyMed (CSK®) ScanSar mode monitoring of the Deepwater Horizon oil spill. Simultaneously, the NEXRAD S-band Doppler radar (KLIX) located in New Orleans was scanning the same portion of ocean. The second case study occurred in Liguria (Italy) on November 4, 2011, during an extraordinary flood event. The same events were observed by the Bric della Croce C-band dual polarization radar located close to Turin (Italy). The polarimetric capability of the ground radars utilized allows discrimination of the composition of the precipitation volume, in particular distinguishing ice from rain. Results shows that for space-borne SAR at X-band, effects due to precipitation on water surfaces can be modeled using coincident ground-based weather radar measurements.

Roberto, N.; Baldini, L.; Facheris, L.; Chandrasekar, V.

2014-07-01

136

Surface degradation of CeO2 stabilized acrylic polyurethane coated thermally treated jack pine during accelerated weathering  

NASA Astrophysics Data System (ADS)

The thermally treated wood is a new value-added product and is very important for the diversification of forestry products. It drew the attention of consumers due to its attractive dark brown color. However, it loses its color when exposed to outside environment. Therefore, development of a protective coating for this value added product is necessary. In the present study, the efficiency of CeO2 nano particles alone or in combination with lignin stabilizer and/or bark extracts in acrylic polyurethane polymer was investigated by performing an accelerated weathering test. The color measurement results after accelerated weathering demonstrated that the coating containing CeO2 nano particles was the most effective whereas visual assessment suggested the coating containing CeO2 nano particles and lignin stabilizer as the most effective coating. The surface polarity changed for all the coatings during weathering and increase in contact angle after weathering suggested cross linking and reorientation of the polymer chain during weathering. The surface chemistry altered during weathering was evaluated by ATR-FTIR analysis. It suggested formation of different carbonyl byproducts during weathering. The chain scission reactions of the urethane linkages were not found to be significant during weathering.

Saha, Sudeshna; Kocaefe, Duygu; Boluk, Yaman; Pichette, Andre

2013-07-01

137

AIRS Observations of DomeC in Antarctica and Comparison with Automated Weather Stations (AWS)  

NASA Technical Reports Server (NTRS)

We compare the surface temperatures at Dome Concordia (DomeC) deduced from AIRS data and two Automatic Weather Stations at Concordia Station: AWS8989 , which has been in operation since December 1996, and AWS.it, for which data are available between January and November 2005. The AWS8989 readings are on average 3 K warmer than the AWS.it readings, with a warmer bias in the Antarctic summer than in the winter season. Although AIRS measures the skin brightness temperature, while the AWS reports the temperature of the air at 3 meter above the surface, the AIRS measurements agree well with the AWS.it readings for all data and separately for the summer and winter seasons, if data taken in the presence of strong surface inversions are filtered out. This can be done by deducing the vertical temperature gradient above the surface directly from the AIRS temperature sounding channels or indirectly by noting that extreme vertical gradients near the surface are unlikely if the wind speed is more than a few meters per second. Since the AIRS measurements are very well calibrated, the agreement with AWS.it is very encouraging. The warmer readings of AWS8989 are likely due to thermal contamination of the AWS8989 site by the increasing activity at Concordia Station. Data from an AWS.it quality station could be used for the evaluation of radiometric accuracy and stability of polar orbiting sounders at low temperatures. Unfortunately, data from AWS.it was available only for a limited time. The thermal contamination of the AWS8989 data makes long-term trends deduced from AWS8989 and possibly results about the rapid Antarctic warming deduced from other research stations on Antarctica suspect. AIRS is the first hyperspectral infrared sounder designed in support of weather forecasting and climate research. It was launched in May 2002 on the EOS Aqua spacecraft into a 704 km altitude polar sun-synchronous orbit. The lifetime of AIRS, estimated before launch to be at least 5 years is, based on the latest evaluation, limited by the amount of attitude control gas on the EOS Aqua spacecraft, which is expected to last through 2015.

Aumann, Hartmut H.; Gregorich, Dave; Broberg, Steve

2006-01-01

138

The Link between Clay Mineral Weathering and the Stabilization of  

E-print Network

The Link between Clay Mineral Weathering and the Stabilization of Ni Surface Precipitates R O B E R of the observed increase in dissolution resistance. Thus, clay mineral weathering and the time-dependent release was derived from weathering of the clay mineral surface. A time-dependent extended X

Sparks, Donald L.

139

Assimilating QuikSCAT Ocean Surface Winds with the Weather Research and Forecasting Model for Surface Wind-Field Simulation over the Chukchi/Beaufort Seas  

NASA Astrophysics Data System (ADS)

To achieve a high-quality simulation of the surface wind field in the Chukchi/Beaufort Sea region, quick scatterometer (QuikSCAT) ocean surface winds were assimilated into the mesoscale Weather Research and Forecasting model by using its three-dimensional variational data assimilation system. The SeaWinds instrument on board the polar-orbiting QuikSCAT satellite is a specialized radar that measures ice-free ocean surface wind speed and direction at a horizontal resolution of 12.5 km. A total of eight assimilation case studies over two five-day periods, 1-5 October 2002 and 20-24 September 2004, were performed. The simulation results with and without the assimilation of QuikSCAT winds were then compared with QuikSCAT data available during the subsequent free-forecast period, coastal station observations, and North American Regional Reanalysis data. It was found that QuikSCAT winds are a potentially valuable resource for improving the simulation of ocean near-surface winds in the Chukchi/Beaufort Seas region. Specifically, the assimilation of QuikSCAT winds improved, (1) offshore surface winds as compared to unassimilated QuikSCAT winds, (2) sea-level pressure, planetary boundary-layer height, as well as surface heat fluxes, and (3) low-level wind fields and geopotential height. Verification against QuikSCAT data also demonstrated the temporal consistency and good quality of QuikSCAT observations.

Fan, Xingang; Krieger, Jeremy R.; Zhang, Jing; Zhang, Xiangdong

2013-07-01

140

Optimal Sites for Supplementary Weather Observations: Simulation with a Small Model  

E-print Network

Anticipating the opportunity to make supplementary observations at locations that can depend upon the current weather situation, the question is posed as to what strategy should be adopted to select the locations, if the greatest improvement in analyses and forecasts is to be realized. To seek a preliminary answer, the authors introduce a model consisting of 40 ordinary differential equations, with the dependent variables representing values of some atmospheric quantity at 40 sites spaced equally about a latitude circle. The equations contain quadratic, linear, and constant terms representing advection, dissipation, and external forcing. Numerical integration indicates that small errors (differences between solutions) tend to double in about 2 days. Localized errors tend to spread eastward as they grow, encircling the globe after about 14 days. In the

Edward N. Lorenz; Kerry A. Emanuel

1998-01-01

141

A twenty-first century California observing network for monitoring extreme weather events  

USGS Publications Warehouse

During Northern Hemisphere winters, the West Coast of North America is battered by extratropical storms. The impact of these storms is of paramount concern to California, where aging water supply and flood protection infrastructures are challenged by increased standards for urban flood protection, an unusually variable weather regime, and projections of climate change. Additionally, there are inherent conflicts between releasing water to provide flood protection and storing water to meet requirements for water supply, water quality, hydropower generation, water temperature and flow for at-risk species, and recreation. In order to improve reservoir management and meet the increasing demands on water, improved forecasts of precipitation, especially during extreme events, is required. Here we describe how California is addressing their most important and costliest environmental issue – water management – in part, by installing a state-of-the-art observing system to better track the area’s most severe wintertime storms.

White, A.B.; Anderson, M.L.; Dettinger, M.D.; Ralph, F.M.; Hinojosa, A.; Cayan, D.R.; Hartman, R.K.; Reynolds, D.W.; Johnson, L.E.; Schneider, T.L.; Cifelli, R.; Toth, Z.; Gutman, S.I.; King, C.W.; Gehrke, F.; Johnston, P.E.; Walls, C.; Mann, D.; Gottas, D.J.; Coleman, T.

2013-01-01

142

Space Weathering Effects in Lunar Soils: The Roles of Surface Exposure Time and Bulk Chemical Composition  

NASA Technical Reports Server (NTRS)

Space weathering effects on lunar soil grains result from both radiation-damaged and deposited layers on grain surfaces. Typically, solar wind irradiation forms an amorphous layer on regolith silicate grains, and induces the formation of surficial metallic Fe in Fe-bearing minerals [1,2]. Impacts into the lunar regolith generate high temperature melts and vapor. The vapor component is largely deposited on the surfaces of lunar soil grains [3] as is a fraction of the melt [4, this work]. Both the vapor-deposits and the deposited melt typically contain nanophase Fe metal particles (npFe0) as abundant inclusions. The development of these rims and the abundance of the npFe0 in lunar regolith, and thus the optical properties, vary with the soil mineralogy and the length of time the soil grains have been exposed to space weathering effects [5]. In this study, we used the density of solar flare particle tracks in soil grains to estimate exposure times for individual grains and then perform nanometer-scale characterization of the rims using transmission electron microscopy (TEM). The work involved study of lunar soil samples with different mineralogy (mare vs. highland) and different exposure times (mature vs. immature).

Zhang, Shouliang; Keller, Lindsay P.

2011-01-01

143

Space Weather Monitoring for ISS Space Environments Engineering and Crew Auroral Observations  

NASA Technical Reports Server (NTRS)

The awareness of potentially significant impacts of space weather on spaceand ground ]based technological systems has generated a strong desire in many sectors of government and industry to effectively transform knowledge and understanding of the variable space environment into useful tools and applications for use by those entities responsible for systems that may be vulnerable to space weather impacts. Essentially, effectively transitioning science knowledge to useful applications relevant to space weather has become important. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts.

Minow, Joseph I.; Pettit, Donald R.; Hartman, William A.

2012-01-01

144

Weather Forecasting  

NSDL National Science Digital Library

This activity (on page 2 of the PDF) is a full inquiry investigation into meteorology and forecasting. Learners will research weather folklore, specifically looking for old-fashioned ways of predicting the weather. Then, they'll record observations of these predictors along with readings from their own homemade barometer, graphing the correct predictions for analysis. Relates to linked video, DragonflyTV: Forecasting.

2012-06-26

145

Weather Instruments  

NSDL National Science Digital Library

This Topic in Depth discusses the variety of instruments used to collect climate and weather data. The first two websites provide simple introductions to the many weather instruments. Bethune Academy's Weather Center (1) discusses the functions of psychrometers, anemometers, weather balloons, thermometers, and barometers. The Illinois State Water Survey (2) furnishes many images of various instruments that collect data daily for legal issues, farmers, educators, students, and researchers. The third website (3), created by the Center for Improving Engineering and Science Education (CIESE), provides a classroom activity to educate users on how to build and use weather instruments. By the end of the group project, students should know all about wind vanes, rain gauges, anemometers, and thermometers. Next, the Miami Museum of Science provides a variety of activities to help students learn about the many weather instruments including wind scales and wind chimes (4). Students can learn about the wind, air pressure, moisture, and temperature. At the fifth website, the Tyson Research Center at Washington University describes the devices it uses in its research (5). At the various links, users can find out the center's many projects that utilize meteorological data such as acid rain monitoring. The sixth website, a pdf document created by Dr. John Guyton at the Mississippi State University Extension Service, provides guidance to teachers about the education of weather patterns and instruments (6). Users can find helpful information on pressure systems, humidity, cloud patterns, and much more. Next, the University of Richmond discusses the tools meteorologists use to learn about the weather (7). While providing materials about the basic tools discussed in the other websites, this site also offers information about weather satellites, radar, and computer models. After discovering the many weather instruments, users can learn about weather data output and analysis at the Next Generation Weather Lab website (8). This expansive website provides an abundance of surface data and upper air data as well as satellite and radar images for the United States.

146

Space Weather Measurements from the Surface of Mars with the RAD Instrument on the Mars Science Laboratory  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD) is a compact, lightweight energetic particle analyzer currently operating on the surface of Mars as part of the Mars Science Laboratory (MSL) Mission. These are the first measurements of the radiation environment on the surface of another planet, and specifically Mars. RAD is providing synoptic measurements of GCR & SEP at a 2nd location in heliosphere (other than near-Earth or L1), and will aid heliospheric modeling over solar cycle. These observations of SEP fluxes will contribute to a SEP event database at Mars and Martian surface to aid prediction of Solar Energetic Particle (SEP) Events, including onset, temporal & size predictions. This presentation will provide an overview of the RAD investigation and present the early measurements of the radiation environment on the surface of Mars and discuss the importance of providing broad heliospheric coverage and situational awareness of space weather as we plan to send humans out into deep space and to Mars. RAD is supported by NASA (HEOMD) under JPL subcontract #1273039 to SwRI, and by DLR in Germany under contract with Christian-Albrechts-Universitat (CAU).

Hassler, D.; Zeitlin, C. J.; Wimmer-Schweingruber, R.; Mars Science Laboratory Science Team

2013-05-01

147

Some statistics of freezing precipitation and rime for the territory of the former USSR from ground-based weather observations  

NASA Astrophysics Data System (ADS)

This work is a continuation of the previous climatological study of freezing precipitation and rime over the USSR territory [ Bezrukova, N.A., Minina, L.S., Naumov, A.Ya., 2000. Freezing precipitation climatology in the former European USSR. Proceedings of the 13th International Conference on Clouds and Precipitation, pp.737-739, Reno, Nevada, USA, 14-18 August 2000; Bezrukova, N.A., Jeck, R.K., Minina, L.S., Khalili, M.F., Stulov, E.A., 2004. 10-year Statistics on Freezing Precipitation across the former USSR from surface weather observations. Proceedings of the 14th International Conference on Clouds and Precipitation, pp.731-734, Bologna, Italy, 19-23 August 2004.] aimed at creating an atlas of the frequency of these phenomena. This study gives considerable information about and a statistical analysis of freezing precipitation and rime events observed over the territory of the former USSR during a decade (1981-1990) and over the European territory of the USSR during two decades (1971-1990). This paper intends to draw the attention of the reader to the atlas and statistics by showing some interesting points. The authors used the data provided by the ground-based weather stations involved in the international exchange of meteorological data. The USSR network's Monthly Meteorological Tables (1971-1990) [Monthly Meteorological Tables, 1971-1990. Part 1, Novosibirsk-Obninsk. (in Russian).] comprising selected daily ground-based meteorological observations from more than 220 stations served as a basis for the analysis. All the types of freezing precipitation (FP) events were given as WMO Codes 56, 57, 66, 67, 24 and freezing fog (FF) deposited rime as WMO Codes 48, 49. The entire territory was divided into six major regions: the Arctic, the European part of the USSR, the Trans-Caucasus, Central Asia, Siberia, and the Far East. The frequency and distribution of events by regions versus temperature, atmospheric pressure, clouds base height, and some other meteorological parameters concerned were obtained. Climatic maps of annual mean, monthly mean, and seasonal mean occurrences of FP and FF were constructed for these regions. The study also analyzes the space-time variability of monthly mean ice-coating duration in hours for the 20-year period of 1971-1990 as observed at over 80 stations in the European part of the USSR (ET), and climatic maps of annual mean and monthly mean ice coating duration for the ET are constructed. The correlation between ice coating duration and height has been evaluated.

Bezrukova, Natalia A.; Jeck, Richard K.; Khalili, Marat F.; Minina, Ludmila S.; Naumov, Alexander Ya.; Stulov, Evgeny A.

2006-11-01

148

Temporal and spatial variation of surface reaction rates in porous media: Applications to silicate weathering  

NASA Astrophysics Data System (ADS)

Percolation theory provides a promising framework for modeling transport in heterogeneous porous media, including hydraulic and electrical conductivity, air permeability, gas diffusivity, and solute transport. Using percolation concepts (e.g., critical path analysis, fractal scaling of percolation clusters, and cluster statistics), we developed a physically-based model for predicting solute transport. Our model predicted spatial solute distributions as a function of time, and arrival time distributions as a function of system size. Our solute transport predictions gave good matches to a wide range of experiments. We now apply our solute transport model to silicate weathering. We assume that surface chemical reactions are at equilibrium at the scale of a single pore, but that at larger length scales, reactions are limited by transport of reactants or products. Using results from published field experiments, we find that the temporal and spatial dependence derived from solute velocity successfully predicts the measured time- and length-dependence of reaction rates and weathering of silicate minerals over a wide range of time and length scale. A similar analysis of lab experiments (uranium breakthrough curves measured in two short and long columns from the Hanford site) indicates that normalized reaction rate versus normalized time follow 2D invasion and 3D random percolation.

Ghanbarian, B.; Hunt, A. G.; Skinner, T. E.; Ewing, R. P.

2013-12-01

149

Groundwater/surface-water interactions on deeply weathered surfaces of low relief: evidence from Lakes Victoria and Kyoga, Uganda  

NASA Astrophysics Data System (ADS)

Little is known of the interactions between groundwater and surface water on deeply weathered landscapes of low relief in the Great Lakes Region of Africa (GLRA). The role of groundwater in sustaining surface-water levels during periods of absent rainfall is disputed and groundwater is commonly excluded from estimations of surface-water balances. Triangulated piezometers installed beside lake gauging stations on Lake Victoria and Lake Kyoga in Uganda provide the first evidence of the dynamic interaction between groundwater and surface water in the GLRA. Stable isotope ratios (2H:1H, 18O:16O) support piezometric evidence that groundwater primarily discharges to lakes but show further that mixing of groundwater and lake water has occurred at one site on Lake Victoria (Jinja). Layered-aquifer heterogeneity, wherein fluvial-lacustrine sands overlie saprolite, gives rise to both rapid and slow groundwater fluxes to lakes which is evident from the recession of borehole hydrographs following recharge events. Darcy throughflow calculations suggest that direct contributions from groundwater to Lake Victoria comprise <1% of the total inflows to the lake. Groundwater/surface-water interactions are strongly influenced by changing drainage base (lake) levels that are controlled, in part, by regional climate variability and dam releases from Lake Victoria (Jinja).

Owor, Michael; Taylor, Richard; Mukwaya, Christine; Tindimugaya, Callist

2011-11-01

150

Energy balance of a glacier surface: Analysis of automatic weather station data from the Morteratschgletscher, Switzerland  

NASA Astrophysics Data System (ADS)

We describe and analyze a complete 1-yr data set from an automatic weather station (AWS) located on the snout of the Morteratschgletscher, Switzerland. The AWS stands freely on the glacier surface and measures pressure, windspeed, wind direction, air temperature and humidity, incoming and reflected solar radiation, incoming and outgoing longwave radiation, snow temperature, and change in surface height (giving melt rates and snow accumulation). The wind is downglacier most of the time. As expected for a flow of katabatic origin, for air temperatures above the melting point we find a correlation between windspeed and temperature. We evaluate all significant components of the surface energy flux. For a (constant) turbulent exchange coefficient of 0.00153 (reference height 3.5 m) we obtain a perfect match between calculated and measured ice melt. The sensible heat flux is positive (towards the glacier surface) all the time with the largest values on fine summer days (daily mean values are typically 100 W m(-2) on the warmest days). The latent heat flux is small and negative in winter. In summer it is mainly positive (condensation), but negative values also occur. Altogether about 75% of the melt energy is supplied by radiation (shortwave and longwave) and 25% by the turbulent fluxes.

Oerlemans, J.; Klok, E. J.

2002-11-01

151

The Main Pillar: Assessment of Space Weather Observational Asset Performance Supporting Nowcasting, Forecasting and Research to Operations  

NASA Technical Reports Server (NTRS)

Space weather forecasting critically depends upon availability of timely and reliable observational data. It is therefore particularly important to understand how existing and newly planned observational assets perform during periods of severe space weather. Extreme space weather creates challenging conditions under which instrumentation and spacecraft may be impeded or in which parameters reach values that are outside the nominal observational range. This paper analyzes existing and upcoming observational capabilities for forecasting, and discusses how the findings may impact space weather research and its transition to operations. A single limitation to the assessment is lack of information provided to us on radiation monitor performance, which caused us not to fully assess (i.e., not assess short term) radiation storm forecasting. The assessment finds that at least two widely spaced coronagraphs including L4 would provide reliability for Earth-bound CMEs. Furthermore, all magnetic field measurements assessed fully meet requirements. However, with current or even with near term new assets in place, in the worst-case scenario there could be a near-complete lack of key near-real-time solar wind plasma data of severe disturbances heading toward and impacting Earth's magnetosphere. Models that attempt to simulate the effects of these disturbances in near real time or with archival data require solar wind plasma observations as input. Moreover, the study finds that near-future observational assets will be less capable of advancing the understanding of extreme geomagnetic disturbances at Earth, which might make the resulting space weather models unsuitable for transition to operations.

Posner, Arik; Hesse, Michael; SaintCyr, Chris

2014-01-01

152

Oscillation Responses to an Extreme Weather Event from a Deep Moored Observing System  

NASA Astrophysics Data System (ADS)

In June 2007 tropical Cyclone Gonu passed directly over an ocean observing system consisting of four, deep autonomous mooring stations along the 3000 m isobath in the northern Arabian Sea. Gonu was the largest cyclone known to have occurred in the Arabian Sea or to strike the Arabian Peninsula. The mooring system was designed by Lighthouse R & D Enterprises, Inc. and installed in cooperation with the Oman Ministry of Agriculture and Fisheries Wealth. The instruments on the moorings continuously recorded water velocities, temperature, conductivity, pressure, dissolved oxygen and turbidity at multiple depths and at hourly intervals during the storm. Near-inertial oscillations at all moorings from thermocline to seafloor are coincident with the arrival of Gonu. Sub-inertial oscillations with periods of 2-10 days are recorded at the post-storm relaxation stage of Gonu, primarily in the thermocline. These oscillations consist of warm, saline water masses, likely originating from the Persian Gulf. Prominent 12.7-day sub-inertial waves, measured at a station ~300 km offshore, are bottom-intensified and have characteristics of baroclinic, topographically-trapped waves. Theoretical results from a topographically-trapped wave model are in a good agreement with the observed 12.7-day waves. The wavelength of the 12.7-day waves is about 590 km calculated from the dispersion relationship. Further analysis suggests that a resonant standing wave is responsible for trapping the 12.7-day wave energy inside the Sea of Oman basin. The observational results reported here are the first measurements of deepwater responses to a tropical cyclone in the Sea of Oman/Arabian Sea. Our study demonstrates the utility of sustained monitoring for studying the impact of extreme weather events on the ocean.

Wang, Z.; Dimarco, S. F.; Stoessel, M. M.; Zhang, X.; Ingle, S.

2011-12-01

153

Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2.  

SciTech Connect

More information: http://daymet.ornl.gov Presenter: Ranjeet Devarakonda Environmental Sciences Division Oak Ridge National Laboratory (ORNL) Daymet: Daily Surface Weather Data and Climatological Summaries provides gridded estimates of daily weather parameters for North America, including daily continuous surfaces of minimum and maximum temperature, precipitation occurrence and amount, humidity, shortwave radiation, snow water equivalent, and day length. The current data product (Version 2) covers the period January 1, 1980 to December 31, 2013 [1]. The prior product (Version 1) only covered from 1980-2008. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the conterminous United States, Mexico, and Southern Canada as meteorological station density allows. Daymet data can be downloaded from 1) the ORNL Distributed Active Archive Center (DAAC) search and order tools (http://daac.ornl.gov/cgi-bin/cart/add2cart.pl?add=1219) or directly from the DAAC FTP site (http://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1219) and 2) the Single Pixel Tool [2] and THREDDS (Thematic Real-time Environmental Data Services) Data Server [3]. The Single Pixel Data Extraction Tool allows users to enter a single geographic point by latitude and longitude in decimal degrees. A routine is executed that translates the (lon, lat) coordinates into projected Daymet (x,y) coordinates. These coordinates are used to access the Daymet database of daily-interpolated surface weather variables. Daily data from the nearest 1 km x 1 km Daymet grid cell are extracted from the database and formatted as a table with one column for each Daymet variable and one row for each day. All daily data for selected years are returned as a single (long) table, formatted for display in the browser window. At the top of this table is a link to the same data in a simple comma-separated text format, suitable for import into a spreadsheet or other data analysis software. The Single Pixel Data Extraction Tool also provides the option to download multiple coordinates programmatically. A multiple extractor script is freely available to download at http://daymet.ornl.gov/files/daymet.zip. The ORNL DAAC s THREDDS data server (TDS) provides customized visualization and access to Daymet time series of North American mosaics. Users can subset and download Daymet data via a variety of community standards, including OPeNDAP, NetCDF Subset service, and Open Geospatial Consortium (OGC) Web Map/Coverage Service. The ORNL DAAC TDS also exposes Daymet metadata through its ncISO service to facilitate harvesting Daymet metadata records into 3rd party catalogs. References: [1] Thornton, P.E., M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, R. Devarakonda, and R.B. Cook. 2014. Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set. Available on-line [http://daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, USA. [2] Devarakonda R., et al. 2012. Daymet: Single Pixel Data Extraction Tool. Available on-line [http://daymet.ornl.go/singlepixel.html]. [3] Wei Y., et al. 2014. Daymet: Thematic Real-time Environmental Data Services. Available on-line [http://daymet.ornl.gov/thredds_tiles.html].

Thornton, Peter E [ORNL; Thornton, Michele M [ORNL; Mayer, Benjamin W [ORNL; Wilhelmi, Nate [National Center for Atmospheric Research (NCAR); Wei, Yaxing [ORNL; Devarakonda, Ranjeet [ORNL; Cook, Robert B [ORNL

2014-01-01

154

Surface albedo based on geostationary satellite observations  

NASA Astrophysics Data System (ADS)

Surface albedo is the fraction of incoming solar radiation reflected by the land surface, and therefore is a sensitive indicator of environmental changes. To this end, surface albedo is identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). NOAA's National Climatic Data Center (NCDC) is implementing the Geostationary Surface Albedo (GSA; Lattanzio and Govaerts, 2010) algorithm for GOES data in support of an activity of the Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM). SCOPE-CM helps coordinate ECV production responding to GCOS, WMO, and CEOS goals. The GSA algorithm was developed jointly by EUMETSAT and Joint Research Centre (JRC) using a method proposed by Pinty et al. (2000) to retrieve surface albedo by processing day-time, cloud-free geostationary observations from a single visible band. Currently, the GSA algorithm generates products operationally at EUMETSAT using geostationary data from satellites at 0° and 63°E and at JMA using 140°E geostationary data. To support development of an aggregate global albedo product, NCDC will apply the GSA algorithm to data from GOES-E (75°W) and GOES-W (135°W). For the GOES implementation, raw GOES observations are calibrated against AVHRR reflectance data available in PATMOS-x. Surface angular anisotropy is then determined through the inversion of the GSA radiative transfer model using multiple geostationary images collected over a day under different illumination conditions. The inversion process additionally requires ancillary total column ozone and water vapor values, which for the GOES implementation are acquired from the 20th Century Reanalysis V2 data set provided by the NOAA/OAR/ESRL PSD. The GSA algorithm produces a 10-day composite surface albedo map. This product will initially be developed for the period 2000-2003. Later, it will be applied to the complete GOES data collection (1978-present) as part of NOAA's Climate Data Record Program.

Matthews, J. L.; Lattanzio, A.; Hankins, B.; Inamdar, A.; Knapp, K.; Privette, J. L.

2011-12-01

155

Data management of geostationary communication satellite telemetry and correlation to space weather observations  

E-print Network

To understand and mitigate the effects of space weather on the performance of geostationary communications satellites, we analyze sixteen years of archived telemetry data from Inmarsat, the UK-based telecommunications ...

Lohmeyer, Whitney Quinne

2013-01-01

156

Sensitivity of free tropospheric carbon monoxide to atmospheric weather states and their persistency: an observational assessment over the Nordic countries  

NASA Astrophysics Data System (ADS)

Among various factors that influence the long-range transport of pollutants in the free troposphere (FT), the prevailing atmospheric weather states probably play the most important role in governing characteristics and efficacy of such transport. The weather states, such as a particular wind pattern, cyclonic or anticyclonic conditions etc, and their degree of persistency determine the spatio-temporal distribution and the final fate of the pollutants. This is especially true in the case of Nordic countries, where baroclinic disturbances and associated weather fronts primarily regulate local meteorology, in contrast to the lower latitudes where convective paradigm plays similar important role. Furthermore, the long-range transport of pollutants in the FT has significant contribution to the total column burden over the Nordic countries. However, there is insufficient knowledge on the large-scale co-variability of pollutants in the FT and atmospheric weather states based solely on observational data over this region. The present study attempts to quantify and understand this statistical co-variability while providing relevant meteorological background. To that end, we select eight weather states that predominantly occur over the Nordic countries and three periods of their persistency (3 days, 5 days, and 7 days), thus providing in total 24 cases to investigate sensitivity of free tropospheric carbon monoxide, an ideal tracer for studying pollutant transport, to these selected weather states. The eight states include four dominant wind directions (namely, NW, NE, SE and SW), cyclonic and anticyclonic conditions, and the enhanced positive and negative phases of the North Atlantic Oscillation (NAO). For our sensitivity analysis, we use recently released Version 6 retrievals of CO at 500 hPa from the Atmospheric Infrared Sounder (AIRS) onboard Aqua satellite covering 11 yr period from September 2002 through August 2013 and winds from the ECMWF's ERA-Interim project to classify weather states for the same 11 yr period. We show that, among the various weather states studied here, southeasterly winds lead to highest observed CO anomalies (up to +8%) over the Nordic countries while transporting pollution from the central and eastern parts of Europe. The second (up to +4%) and third highest (up to +2.5%) CO anomalies are observed when winds are northwesterly (facilitating inter-continental transport from polluted North American regions) and during the enhanced positive phase of the NAO respectively. Higher than normal CO anomalies are observed during anticyclonic conditions (up to +1%) compared to cyclonic conditions. The cleanest conditions are observed when winds are northeasterly and during the enhanced negative phases of the NAO, when relatively clean Arctic air masses are transported over the Nordic regions in the both cases. In case of nearly all weather states, the CO anomalies consistently continue to increase or decrease as the degree of persistency of a weather state is increased. The results of this sensitivity study further provide an observational basis for the process-oriented evaluation of chemistry transport models, especially with regard to the representation of large-scale coupling of chemistry and local weather states and its role in the long-range transport of pollutants in such models.

Thomas, M. A.; Devasthale, A.

2014-04-01

157

Sensitivity of free tropospheric carbon monoxide to atmospheric weather states and their persistency: an observational assessment over the Nordic countries  

NASA Astrophysics Data System (ADS)

Among various factors that influence the long-range transport of pollutants in the free troposphere (FT), the prevailing atmospheric weather states probably play the most important role in governing characteristics and efficacy of such transport. The weather states, such as a particular wind pattern, cyclonic or anticyclonic conditions, and their degree of persistency determine the spatio-temporal distribution and the final fate of the pollutants. This is especially true in the case of Nordic countries, where baroclinic disturbances and associated weather fronts primarily regulate local meteorology, in contrast to the lower latitudes where a convective paradigm plays a similarly important role. Furthermore, the long-range transport of pollutants in the FT has significant contribution to the total column burden over the Nordic countries. However, there is insufficient knowledge on the large-scale co-variability of pollutants in the FT and atmospheric weather states based solely on observational data over this region. The present study attempts to quantify and understand this statistical co-variability while providing relevant meteorological background. To that end, we select eight weather states that predominantly occur over the Nordic countries and three periods of their persistency (3 days, 5 days, and 7 days), thus providing in total 24 cases to investigate sensitivity of free tropospheric carbon monoxide, an ideal tracer for studying pollutant transport, to these selected weather states. The eight states include four dominant wind directions (namely, NW, NE, SE and SW), cyclonic and anticyclonic conditions, and the enhanced positive and negative phases of the North Atlantic Oscillation (NAO). For our sensitivity analysis, we use recently released Version 6 retrievals of CO at 500 hPa from the Atmospheric Infrared Sounder (AIRS) onboard Aqua satellite covering the 11-year period from September 2002 through August 2013 and winds from the ECMWF's ERA-Interim project to classify weather states for the same 11-year period. We show that, among the various weather states studied here, southeasterly winds lead to highest observed CO anomalies (up to +8%) over the Nordic countries while transporting pollution from the central and eastern parts of Europe. The second (up to +4%) and third highest (up to +2.5%) CO anomalies are observed when winds are northwesterly (facilitating inter-continental transport from polluted North American regions) and during the enhanced positive phase of the NAO respectively. Higher than normal CO anomalies are observed during anticyclonic conditions (up to +1%) compared to cyclonic conditions. The cleanest conditions are observed when winds are northeasterly and during the enhanced negative phases of the NAO, when relatively clean Arctic air masses are transported over the Nordic regions in the both cases. In the case of nearly all weather states, the CO anomalies consistently continue to increase or decrease as the degree of persistency of a weather state is increased. The results of this sensitivity study further provide an observational basis for the process-oriented evaluation of chemistry transport models, especially with regard to the representation of large-scale coupling of chemistry and local weather states and its role in the long-range transport of pollutants in such models.

Thomas, M. A.; Devasthale, A.

2014-11-01

158

Understanding Aviation Meteorology and Weather Hazards with Ground-Based Observations  

Microsoft Academic Search

\\u000a Meteorology is no doubt important for aviation, as weather hazards have a significant negative impact on aircraft safety and\\u000a traffic delay. Based on recent surveys, 20–30% of worldwide air accidents and as much as 22% of air traffic delays are due\\u000a to to adverse weather conditions. Information on thunderstorms, ceiling and visibility, wind shear, turbulence, and aircraft\\u000a icing conditions are

Christian Pagé

159

Exploring Weather  

NSDL National Science Digital Library

Second Grade Standard 3: Students will develop an understanding of their environment. Objective 2: Observe and describe weather. Indicator a: Observe and describe patterns of change in weather. Monday, February 1st: Look at the five-day forecast for Salt Lake City, Utah at Five day forecasts. The high temperature for the day will be in red and the low temperature will be in blue. Make sure you look at the temperature listed in degrees Farenheit (F) not degrees Celcius (C). Make ...

Miss Emily

2010-01-29

160

Mechanism of tropical low-cloud response to surface warming using weather and climate simulations  

NASA Astrophysics Data System (ADS)

To understand mechanisms of shortwave cloud-radiative feedback to global warming in a general circulation model (GCM), we analyzed the response of tropical clouds to uniform increase of sea surface temperature in an atmospheric GCM with two different experimental designs: a single Atmospheric Model Intercomparison Project (AMIP) run for 30 years and a series of 10 day weather hindcasts following the Transpose AMIP II (TAMIP). Given the fast time scale of cloud processes, the hindcast ensemble can capture initial transient responses toward equilibrium obtained in the AMIP experiment, which shows a reduction of low clouds over tropical subsidence regions. The reduction of clouds occurs in the first 10 days in TAMIP when the marine boundary layer (MBL) is destabilized because of contrast between fast and slow warming in the MBL and aloft. Enhanced evaporation from the sea surface that should moisten the MBL through turbulent mixing is suppressed by a reduced surface wind speed associated with a slowdown of the Walker circulation. The sign of the low-cloud change over the subsidence regime is thus determined roughly by competition between convective drying and turbulent moistening of the MBL.

Demoto, Satoru; Watanabe, Masahiro; Kamae, Youichi

2013-05-01

161

The rate of chemical weathering of pyrite on the surface of Venus  

NASA Technical Reports Server (NTRS)

This abstract reports results of an experimental study of the chemical weathering of pyrite (FeS2) under Venus-like conditions. This work, which extends the earlier study by Fegley and Treiman, is part of a long range research program to experimentally measure the rates of thermochemical gas-solid reactions important in the atmospheric-lithospheric sulfur cycle on Venus. The objectives of this research are (1) to measure the kinetics of thermochemical gas-solid reactions responsible for both the production (e.g., anhydrite formation) and destruction (e.g., pyrrhotite oxidation) of sulfur-bearing minerals on the surface of Venus and (2) to incorporate these and other constraints into holistic models of the chemical interactions between the atmosphere and surface of Venus. Experiments were done with single crystal cubes of natural pyrite (Navajun, Logrono, Spain) that were cut and polished into slices of known weight and surface area. The slices were isothermally heated at atmospheric pressure in 99.99 percent CO2 (Coleman Instrument Grade) at either 412 C (685 K) or 465 C (738 K) for time periods up to 10 days. These two isotherms correspond to temperatures at about 6 km and 0 km altitude, respectively, on Venus. The reaction rate was determined by measuring the weight loss of the reacted slices after removal from the furnace. The reaction products were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy on the SEM.

Fegley, B., Jr.; Lodders, K.

1993-01-01

162

Spaceborne radar observation of the earth surface  

NASA Technical Reports Server (NTRS)

Seasat SAR images are being analyzed to determine the potential of spaceborne radars for earth resources and ocean surface observation. Examples are presented for a variety of applications in structural mapping, lithological classification, soil moisture detection, polar ice motion monitoring and ocean features observation. These examples are briefly discussed with emphasis on the future research needed to further the capability of radar sensors, by themselves or in combination with other sensors. A brief discussion is then given on the spaceborne sensors which are required and planned to meet these needs.

Elachi, C.

1981-01-01

163

Global surface-based cloud observation for ISCCP  

NASA Technical Reports Server (NTRS)

Visual observations of cloud cover are hindered at night due to inadequate illumination of the clouds. This usually leads to an underestimation of the average cloud cover at night, especially for the amounts of middle and high clouds, in climatologies on surface observations. The diurnal cycles of cloud amounts, if based on all the surface observations, are therefore in error, but they can be obtained more accurately if the nighttime observations are screened to select those made under sufficient moonlight. Ten years of nighttime weather observations from the northern hemisphere in December were classified according to the illuminance of moonlight or twilight on the cloud tops, and a threshold level of illuminance was determined, above which the clouds are apparently detected adequately. This threshold corresponds to light from a full moon at an elevation angle of 6 degrees or from a partial moon at higher elevation, or twilight from the sun less than 9 degrees below the horizon. It permits the use of about 38% of the observations made with the sun below the horizon. The computed diurnal cycles of total cloud cover are altered considerably when this moonlight criterion is imposed. Maximum cloud cover over much of the ocean is now found to be at night or in the morning, whereas computations obtained without benefit of the moonlight criterion, as in our published atlases, showed the time of maximum to be noon or early afternoon in many regions. Cloud cover is greater at night than during the day over the open oceans far from the continents, particularly in summer. However, near noon maxima are still evident in the coastal regions, so that the global annual average oceanic cloud cover is still slightly greater during the day than at night, by 0.3%. Over land, where daytime maxima are still obtained but with reduced amplitude, average cloud cover is 3.3% greater during the daytime. The diurnal cycles of total cloud cover we obtain are compared with those of ISCCP for a few regions; they are generally in better agreement if the moonlight criterion is imposed on the surface observations. Using the moonlight criterion, we have analyzed ten years (1982-1991) of surface weather observations over land and ocean, worldwide, for total cloud cover and for the frequency of occurrence of clear sky, fog and precipitation The global average cloud cover (average of day and night) is about 2% higher if we impose the moonlight criterion than if we use all observations. The difference is greater in winter than in summer, because of the fewer hours of darkness in the summer. The amplitude of the annual cycle of total cloud cover over the Arctic Ocean and at the South Pole is diminished by a few percent when the moonlight criterion is imposed. The average cloud cover for 1982-1991 is found to be 55% for northern hemisphere land, 53% for southern hemisphere land, 66% for northern hemisphere ocean, and 70% for southern hemisphere ocean, giving a global average of 64%. The global average for daytime is 64.6% for nighttime 63.3%.

1994-01-01

164

Observing Global Surface Water Flood Dynamics  

NASA Astrophysics Data System (ADS)

Flood waves moving along river systems are both a key determinant of globally important biogeochemical and ecological processes and, at particular times and particular places, a major environmental hazard. In developed countries, sophisticated observing networks and ancillary data, such as channel bathymetry and floodplain terrain, exist with which to understand and model floods. However, at global scales, satellite data currently provide the only means of undertaking such studies. At present, there is no satellite mission dedicated to observing surface water dynamics and, therefore, surface water scientists make use of a range of sensors developed for other purposes that are distinctly sub-optimal for the task in hand. Nevertheless, by careful combination of the data available from topographic mapping, oceanographic, cryospheric and geodetic satellites, progress in understanding some of the world's major river, floodplain and wetland systems can be made. This paper reviews the surface water data sets available to hydrologists on a global scale and the recent progress made in the field. Further, the paper looks forward to the proposed NASA/CNES Surface Water Ocean Topography satellite mission that may for the first time provide an instrument that meets the needs of the hydrology community.

Bates, Paul D.; Neal, Jefferey C.; Alsdorf, Douglas; Schumann, Guy J.-P.

2014-05-01

165

Sublimation on the Greenland Ice Sheet from automated weather station observations  

NASA Astrophysics Data System (ADS)

Greenland Climate Network (GC-Net) surface meteorological observations are used to estimate net surface water vapor flux at ice sheet sites. Results from aerodynamic profile methods are compared with eddy correlation and evaporation pan measurements. Two profile method types are applied to hourly data sets spanning 1995.4 to 2000.4. One method type is shown to accurately gauge sublimation using two humidity and wind speed measurement levels. The other "bulk" method type is shown to underestimate condensation, as it assumes surface saturation. General climate models employ bulk methods and, consequently, underestimate deposition. Loss of water vapor by the surface predominates in summer at lower elevations, where bulk methods agree better with two-level methods. Annual net water vapor flux from the two-level method is as great as -87±27 mm at 960 m elevation and -74±23 mm at equilibrium line altitude in western Greenland. At an undulation trough site, net deposition is observed (+40 mm ±12). At the adjacent crest site 6 km away and at 50 m higher elevation, net sublimation predominates. At high-elevation sites, the annual water vapor flux is positive, up to +32±9 mm at the North Greenland Ice core Project (NGRIP) and +6±2 mm at Summit. Sublimation is mapped using trend surface fits to calculated sublimation in terms of elevation and latitude. The resulting ice sheet total sublimation is -0.62 ± 0.25 × 1014 kg yr-1 for the two-level profile method and -1.2 ± 0.65 × 1014 kg yr-1 for the one-level method, indicating 12% or 23% precipitation loss, respectively. Monthly, seasonal, and annual sublimation grids and the mapping functions are available on the internet at http://cires.colorado.edu/steffen.

Box, Jason E.; Steffen, Konrad

2001-12-01

166

Impact of the Mediterranean Sea Surface Temperatures from a Weather Regimes Classification Approach  

NASA Astrophysics Data System (ADS)

Weather Regimes (WR) have been defined over the Euro-Mediterranean region [60W-60E; 15N-70N] from May to October season using the daily Sea Level Pressure, 700 hPa geopotential height and specific humidity from ERA-interim dataset over the period 1989-2008. Computations are based on a neural network classification technique referred to as Self Organizing Maps and the WR produced can be used by the community for comparison with other periods, projection onto model outputs, seasonal prediction, or teleconnection studies. This work particularly examines the relationship between Mediterranean Sea Surface Temperatures and West African rainfall through the WR classification. Our results suggest that changes in particular WR frequencies associated with anomalous Mediterranean SST can account for part of interannual rainfall variability. Thus during anomalous wet (dry) years in West Africa, both higher frequencies of occurrence of WR related to negative (positive) summer NAO-like pattern and less frequent WR related to positive (negative) summer NAO-like pattern are attested in July and August (hereafter SN- and SN+). This is associated with a zonal symmetric pattern, consistent along the middle troposphere, i.e. a low pressure anomaly centered over 50N-20W and Eurasia (Greenland) and a high pressure anomaly centered over Iceland (central Europe) for SN- (SN+) WR. Another striking characteristic of SN- (SN+) WR is southeastward (southwestward) surface anomalous winds flowing from (to) the Atlantic ocean at 20N and therefore able to enhance (weaken) wet convection. Sea Surface Temperature associated with SN- WR shows a warming of the Mediterranean in July and the opposite with SN+ WR in August, suggesting that temperature anomalies could be a precursor in the change of frequency of SN- and SN+ WR and therefore impacts on WA rainfall.

Polo, Irene; Ullmann, Albin; Roucou, Pascal; Fontaine, Bernard

2010-05-01

167

Doppler shift observations of severe tropospheric weather effects in the ionosphere  

Microsoft Academic Search

Tropospheric severe weather events are regarded as an important natural source of infrasound. They influence the ionosphere through the upward propagating waves. Due to temperature profile in the lower atmosphere, the infrasonic waves are focused upwards and most of the radiated energy can propagate to the upper atmosphere. Detection of infrasonic waves requires sampling in short intervals or preferably continuous

T. Sindelarova; D. Buresova; J. Lastovicka; J. Chum

2007-01-01

168

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is a set of computer-based learning modules that teach students about meteorology from the point of view of learning how to forecast the weather. The modules were designed as the primary teaching resource for a seminar course on weather forecasting at the introductory college level (originally METR 151, later ATMO 151) and can also be used in the laboratory component of an introductory atmospheric science course. The modules assume no prior meteorological knowledge. In addition to text and graphics, the modules include interactive questions and answers designed to reinforce student learning. The module topics are: 1. How to Access Weather Data, 2. How to Read Hourly Weather Observations, 3. The National Collegiate Weather Forecasting Contest, 4. Radiation and the Diurnal Heating Cycle, 5. Factors Affecting Temperature: Clouds and Moisture, 6. Factors Affecting Temperature: Wind and Mixing, 7. Air Masses and Fronts, 8. Forces in the Atmosphere, 9. Air Pressure, Temperature, and Height, 10. Winds and Pressure, 11. The Forecasting Process, 12. Sounding Diagrams, 13. Upper Air Maps, 14. Satellite Imagery, 15. Radar Imagery, 16. Numerical Weather Prediction, 17. NWS Forecast Models, 18. Sources of Model Error, 19. Sea Breezes, Land Breezes, and Coastal Fronts, 20. Soundings, Clouds, and Convection, 21. Snow Forecasting.

Nielsen-Gammon, John

1996-09-01

169

Environmental Education Tips: Weather Activities.  

ERIC Educational Resources Information Center

Provides weather activities including questions, on weather, heating the earth's surface, air, tools of the meteorologist, clouds, humidity, wind, and evaporation. Shows an example of a weather chart activity. (RT)

Brainard, Audrey H.

1989-01-01

170

A statistical–dynamical scheme for reconstructing ocean forcing in the Atlantic. Part I: weather regimes as predictors for ocean surface variables  

Microsoft Academic Search

The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere\\u000a decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to\\u000a 2002. Daily 500 hPa geopotential height and 1,000 hPa wind anomaly maps are classified following a weather-typing approach\\u000a to describe the North Atlantic and tropical Atlantic atmospheric

Christophe Cassou; Marie Minvielle; Laurent Terray; Claire Périgaud

2011-01-01

171

Weather Maps in Motion  

NSDL National Science Digital Library

In this activity, students learn to interpret current weather maps. They will observe weather map loop animations on the internet, learn the concept of Zulu time (Universal Time Coordinated, UTC) and visualize the movement of fronts and air masses. They will then analyze a specific weather station model, generate a meteogram from their observations, and answer a set of questions about their observations.

Charles Burrows

172

Australian Severe Weather  

NSDL National Science Digital Library

The Australian Severe Weather Web site is maintained by self proclaimed severe weather enthusiasts Michael Bath and Jimmy Deguara. Other weatherphobes will fully appreciate what the authors have assembled. Everything from weather images, storm news, tropical cyclone data, bush fire and wild fire information, weather observation techniques, and even video clips and Web cam links. Although these other items make the site well rounded, the extensive amount of categorized weather pictures (which are quite extraordinary) are reason enough to visit.

173

Weathering of glasses for solar applications  

NASA Astrophysics Data System (ADS)

The weathering of several glasses being considered for solar applications has been studied by a number of surface characterization techniques including optical spectroscopy, optical and scanning electron microscopy, sputter-through Auger analysis, ESCA, SIMS, dye penetration testing, surface profile measurements and resonant nuclear reaction profiling. Significant weathering effects were observed only for the soda-lime-silicate glasses. For soda-lime-silicate glasses, the results indicate that the first stage of weathering is the formation of a low-density anti-reflection film on the glass surface. Growth of this film eventually results in spalling of the glass surface and severe degradation of the optical quality of the glass. Float glasses exhibit significantly better weathering resistance on their tin-rich surface than on the tin-poor surface.

Shelby, J. E.; Vitko, J., Jr.; Pantano, C. G.

1980-09-01

174

Comparative Analysis of Thunderstorm Activity in the West Caucasus According to the Instrumental Measurements and Weather Stations Observations  

NASA Astrophysics Data System (ADS)

The number of thunderstorms days is one of the main characteristics of thunderstorms. In most cases, the number of days with different meteorological phenomena are the climate characteristic of the area. This characteristic is a common climate indicator. The comparative analysis of thunderstorms days quantity, received with lightning detector LS 8000 by Vaisala and weather stations of Krasnodar District (Russia), is presented. For this purpose the Krasnodar region was divided into 19 sites. The thunderstorm days amount and their comparison were conducted for each site according to the data of weather stations and LS 8000 lightning detectors. Totally 29 weather stations are located in this area. The number of thunderstorm days per year for the period of 2009-2012 was determined according to data, received from stations. It was received that average annual number of thunderstorm days for this area was from 33 to 39 days. The majority of thunderstorm days per year (up to 77) was registered in the south of Krasnodar region and on the Black Sea coast. The lowest thunderstorm activity (about 20 days) was observed in the North of the region. To compare visual and voice data for calculating thunderstorm days quantity of the Krasnodar region, the day was considered thundery if at least one weather station registered a storm. These instrumental observations of thunderstorms allow to obtain the basic characteristics and features of the distribution of thunderstorm activity over a large territory for a relatively short period of time. However, some characteristics such as thunderstorms intensity, damages from lightning flashes and others could be obtained only with instrumental observations. The territory of gathering thunderstorm discharges data by system LS8000 is limited by perimeter of 2250 km and square of 400 000 km2. According to the instrumental observations, the majority of storm activity also takes place on the Black Sea coast, near the cities of Sochi and Tuapse. Thus the number of thunderstorm days data characterized by the values from 49 to 158. To compare instrumental and visual-voice observations the difference between thunderstorms days quantity, obtained with visual-voice and instrumental methods, was selected as an indicator of thunderstorm activity. Total number of thunderstorm days in the Krasnodar region during 4 years is 565 according to the lightning detectors and 519 according to the weather stations. The presence of significant differences was revealed to compare number of thunderstorm days between instrumental observations and weather stations data. Thus the value of the average number of thunderstorms days on 29 meteorological stations of the Krasnodar region is reached 33-39 days. At the same time, 49-138 thunderstorm days were recorded according to the LS8000 system. This difference is caused by two factors: 1) limitations of visual-audio thunderstorms detection method at weather stations; 2) development of thunderstorms in a limited areas of the Krasnodar region, which is not the whole territory.

Knyazeva, Zalina; Gergokova, Zainaf; Gyatov, Ruslan; Boldyreff, Anton

2014-05-01

175

A simple parameterization of the short-wave aerosol optical properties for surface direct and diffuse irradiances assessment in a numerical weather model  

NASA Astrophysics Data System (ADS)

Broadband short-wave (SW) surface direct and diffuse irradiances are not typically within the set of output variables produced by numerical weather prediction (NWP) models. However, they are frequently requested for solar energy applications. In order to compute them, a detailed representation of the aerosol optical properties is important. Nonetheless, NWP models typically oversimplify aerosol representation or even neglect their effect. In this work, a flexible method to account for the SW aerosol optical properties in the computation of broadband SW surface direct and diffuse irradiances is presented. It only requires aerosol optical depth at 0.55 ?m and knowledge of the type of predominant aerosol. Other parameters needed to consider spectral aerosol extinction, namely, Angström exponent, aerosol single-scattering albedo and aerosol asymmetry factor, are parameterized. The parameterization has been tested using the Rapid Radiative Transfer Model for climate and weather models (RRTMG) SW scheme of the Weather Research and Forecasting (WRF) NWP model for data over the continental US. In principle, it can be adapted to any other SW radiative transfer band model. It has been verified against a control experiment and using data from five radiometric stations in the contiguous US. The control experiment consisted of a clear-sky evaluation of the RRTMG solar radiation estimates obtained in WRF when RRTMG is driven with ground-observed aerosol optical properties. Overall, the verification has shown satisfactory results for both broadband SW surface direct and diffuse irradiances. The parameterization has proven effective in significantly reducing the prediction error and constraining the seasonal bias in clear-sky conditions to within the typical observational error expected in well maintained radiometers.

Ruiz-Arias, J. A.; Dudhia, J.; Gueymard, C. A.

2014-06-01

176

Space Weathering Products Found on the Surfaces of the Itokawa Dust Particles: A Summary of the Initial Analysis  

NASA Technical Reports Server (NTRS)

Surfaces of airless bodies exposed to interplanetary space gradually have their structures, optical properties, chemical compositions, and mineralogy changed by solar wind implantation and sputtering, irradiation by galactic and solar cosmic rays, and micrometeorite bombardment. These alteration processes and the resultant optical changes are known as space weathering [1, 2, 3]. Our knowledge of space weathering has depended almost entirely on studies of the surface materials returned from the Moon and regolith breccia meteorites [1, 4, 5, 6] until the surface material of the asteroid Itokawa was returned to the Earth by the Hayabusa spacecraft [7]. Lunar soil studies show that space weathering darkens the albedo of lunar soil and regolith, reddens the slopes of their reflectance spectra, and attenuates the characteristic absorption bands of their reflectance spectra [1, 2, 3]. These changes are caused by vapor deposition of small (<40 nm) metallic Fe nanoparticles within the grain rims of lunar soils and agglutinates [5, 6, 8]. The initial analysis of the Itokawa dust particles revealed that 5 out of 10 particles have nanoparticle-bearing rims, whose structure varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles (npFe) exist in a thin (5-15 nm) surface layer (zone I) on olivine, low-Ca pyroxene, and plagioclase, suggestive of vapor deposition. Sulfur-free npFe exist deeper inside (<60 nm) ferromagnesian silicates (zone II). Their texture suggests formation by amorphization and in-situ reduction of Fe2+ in ferromagnesian silicates [7]. On the other hand, nanophase metallic iron (npFe0) in the lunar samples is embedded in amorphous silicate [5, 6, 8]. These textural differences indicate that the major formation mechanisms of the npFe0 are different between the Itokawa and the lunar samples. Here we report a summary of the initial analysis of space weathering of the Itokawa dust particles.

Noguchi, T.; Kimura, M.; Hashimoto, T.; Konno, M.; Nakamura, T.; Ogami, T.; Ishida, H.; Sagae, R.; Tsujimoto, S.; Tsuchiyama, A,; Zolensky, M. E.; Tanaka, M.; Fujimura, A.; Abe, M.; Yada, T.; Mukai, T.; Ueno, M.; Okada, T.; Shirai, K.; Ishibashi, Y.; Okazaki, R.

2012-01-01

177

Modeling land-surface processes and land-atmosphere interactions in the community weather and regional climate WRF model (Invited)  

NASA Astrophysics Data System (ADS)

The Weather Research and Forecasting (WRF) model has been widely used with high-resolution configuration in the weather and regional climate communities, and hence demands its land-surface models to treat not only fast-response processes, such as plant evapotranspiration that are important for numerical weather prediction but also slow-evolving processes such as snow hydrology and interactions between surface soil water and deep aquifer. Correctly representing urbanization, which has been traditionally ignored in coarse-resolution modeling, is critical for applying WRF to air quality and public health research. To meet these demands, numerous efforts have been undertaken to improve land-surface models (LSM) in WRF, including the recent implementation of the Noah-MP (Noah Multiple-Physics). Noah-MP uses multiple options for key sub-grid land-atmosphere interaction processes (Niu et al., 2011; Yang et al., 2011), and contains a separate vegetation canopy representing within- and under-canopy radiation and turbulent processes, a multilayer physically-based snow model, and a photosynthesis canopy resistance parameterization with a dynamic vegetation model. This paper will focus on the interactions between fast and slow land processes through: 1) a benchmarking of the Noah-MP performance, in comparison to five widely-used land-surface models, in simulating and diagnosing snow evolution for complex terrain forested regions, and 2) the effects of interactions between shallow and deep aquifers on regional weather and climate. Moreover, we will provide an overview of recent improvements of the integrated WRF-Urban modeling system, especially its hydrological enhancements that takes into account the effects of lawn irrigation, urban oasis, evaporation from pavements, anthropogenic moisture sources, and a green-roof parameterization.

Chen, F.; Barlage, M. J.

2013-12-01

178

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is one of several online guides produced by the Weather World 2010 project at the University of Illinois. These guides use multimedia technology and the dynamic capabilities of the web to incorporate text, colorful diagrams, animations, computer simulations, audio, and video to introduce topics and concepts in the atmospheric sciences. This module introduces forecast methods and the numerous factors one must consider when attempting to make an accurate forecast. Sections include forecasting methods for different scenarios, surface features affecting forecasting, forecasting temperatures for day and night, and factors for forecasting precipitation.

2010-01-01

179

Weathering of glasses for solar applications  

Microsoft Academic Search

The weathering of several glasses being considered for solar applications has been studied by a number of surface characterization techniques including optical spectroscopy, optical and scanning electron microscopy, sputter-through Auger analysis, ESCA, SIMS, dye penetration testing, surface profile measurements and resonant nuclear reaction profiling. Significant weathering effects were observed only for the soda-lime-silicate glasses. For soda-lime-silicate glasses, the results indicate

J. E. Shelby; J. Vitko Jr.; C. G. Pantano

1980-01-01

180

Observed Changes at the Surface of the Arctic Ocean  

NASA Astrophysics Data System (ADS)

The Arctic has long been considered a harbinger of global climate change since simulations with global climate models predict that if the concentration of CO2 in the atmosphere doubles, the Arctic would warm by more than 5°C, compared to a warming of 2°C for subpolar regions (Manabe et al., 1991). And indeed, studies of the observational records show polar amplification of the warming trends (e.g. Serreze and Francis, 2004). These temperature trends are accompanied by myriad concurrent changes in Arctic climate. One of the first indicators of Arctic climate change was found by Walsh et al. (1996) using sea level pressure (SLP) data from the International Arctic Buoy Programme (IABP, http://iabp.apl.washington.edu). In this study, they showed that SLP over the Arctic Ocean decreased by over 4 hPa from 1979 - 1994. The decreases in SLP (winds) over the Arctic Ocean, forced changes in the circulation of sea ice and the surface ocean currents such that the Beaufort Gyre is reduced in size and speed (e.g. Rigor et al., 2002). Data from the IABP has also been assimilated into the global surface air temperature (SAT) climatologies (e.g. Jones et al. 1999), and the IABP SAT analysis shows that the temperature trends noted over land extend out over the Arctic Ocean. Specifically, Rigor et al. (2000) found warming trends in SAT over the Arctic Ocean during win¬ter and spring, with values as high as 2°C/decade in the eastern Arctic during spring. It should be noted that many of the changes in Arctic climate were first observed or explained using data from the IABP. The observations from IABP have been one of the cornerstones for environmental forecasting and studies of climate and climate change. These changes have a profound impact on wildlife and people. Many species and cultures depend on the sea ice for habitat and subsistence. Thus, monitoring the Arctic Ocean is crucial not only for our ability to detect climate change, but also to improve our understanding of the Arctic and global climate system, and for forecasting weather and sea ice conditions. The IABP provides the longest continuing record of observations for the Arctic Ocean.

Ortmeyer, M.; Rigor, I.

2004-12-01

181

PV powering a weather station for severe weather  

SciTech Connect

A natural disaster, such as Hurricane Andrew, destroys thousands of homes and businesses. The destruction from this storm left thousands of people without communications, potable water, and electrical power. This prompted the Florida Solar Energy Center to study the application of solar electric power for use in disasters. During this same period, volunteers at the Tropical Prediction Center at the National Hurricane Center (NHC), Miami, Florida and the Miami Office of the National Weather Service (NWS) were working to increase the quantity and quality of observations received from home weather stations. Forecasters at NHC have found surface reports from home weather stations a valuable tool in determining the size, strength and course of hurricanes. Home weather stations appear able to record the required information with an adequate level of accuracy. Amateur radio, utilizing the Automatic Packet Report System, (APRS) can be used to transmit this data to weather service offices in virtually real time. Many weather data collecting stations are at remote sites which are not readily serviced by dependable commercial power. Photovoltaic (solar electric) modules generate electricity and when connected to a battery can operate as a stand alone power system. The integration of these components provides an inexpensive standalone system. The system is easy to install, operates automatically and has good communication capabilities. This paper discusses the design criteria, operation, construction and deployment of a prototype solar powered weather station.

Young, W. Jr. [Florida Solar Energy Center, Cocoa, FL (United States); Schmidt, J. [Joe Schmidt, Inc., Miami, FL (United States)

1997-12-31

182

Seasonal changes in Titan's weather patterns and the evolution and implications of accompanying surface changes  

NASA Astrophysics Data System (ADS)

Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to low latitudes [1,2]. Observations by Cassini ISS over the ensuing ~1.5 yr revealed surface changes to be short-lived; few rain-darkened areas persisted through 2011. In an unsaturated permeable medium, infiltration rates are >20 mm/week [3], so persistence of surface liquids over several months suggests that either an impermeable layer or the local methane table lies close to the surface. Evaporation rates >1 mm/week are predicted at low latitudes [4] and 20 mm/week has been documented at Titan's poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had ponded liquid 2.5-50 cm deep. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match clouds or other surface units [6]. Interpretations include cleaning by runoff [2] or deposition of a fine-grained volatile solid as the result of evaporative cooling of the surface [6]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, possibly due to evaporation/sublimation of the bright material or re-deposition of darker hydrocarbons by aeolian transport or precipitation from the atmosphere. Cassini and Earth-based observers monitor Titan frequently, but few clouds have been observed since Fall 2010, which may indicate that enough methane was removed from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a 2004 outburst of south-polar clouds [7], which also appeared to produce significant rainfall [8]. [1] Turtle et al., GRL 38, L03203, doi:10.1029/2010GL046266, 2011. [2] Turtle et al., Science 331, 10.1126/science.1201063. 2011. [3] Hayes et al., GRL 35, L09204, 2008. [4] Schneider et al., Nature 481, doi:10.1038/nature10666, 2012. [5] Hayes et al., Icarus 211, 2011. [6] Barnes et al., LPSC XXXXIII, 2012. [7] Schaller et al., Icarus 184, 2006. [8] Turtle et al., GRL 36, L02204, doi:10.1029/2008GL036186, 2009.

Turtle, Elizabeth; McEwen, Alfred

2012-07-01

183

Space Weathering Processes on Mercury  

NASA Technical Reports Server (NTRS)

Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will incur the effects of space weathering. These weathering processes are capable of both creating regolith and altering its optical properties. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes as well as the products of those processes. It should be possible to observe the effects of these differences in Vis/NIR spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the iron content of the Mercurian surface. Theoretical and experimental work has been undertaken in order to better understand these consequences.

Noble, S. K.; Pieters, C. M.

2002-01-01

184

Comparison of Arctic clouds between European Center for Medium-Range Weather Forecasts simulations and Atmospheric Radiation Measurement Climate Research Facility long-term observations at the North Slope of Alaska Barrow site  

Microsoft Academic Search

This study evaluated the European Center for Medium-Range Weather Forecasts (ECMWF) model-simulated clouds and boundary layer (BL) properties based upon Atmospheric Radiation Measurement Climate Research Facility observations at the North Slope of Alaska site during 1999–2007. The ECMWF model-simulated near-surface humidity had seasonal dependent biases as large as 20%, while also experiencing difficulty representing BL temperature inversion height and strength

Ming Zhao; Zhien Wang

2010-01-01

185

Supplementary Material Biases in regional carbon budgets from covariation of surface fluxes and weather in  

E-print Network

of 300 years simulated). The average seasonal cycle has been added back to the synthetic time and weather in transport model inversions I.N. Williams1, W.J. Riley1, M.S. Torn1, S.C. Biraud1, and M to: Ian N. Williams (inw@uchicago.edu) S1. Inverse transform sampling method The stochastic model

Meskhidze, Nicholas

186

Evaluating the Impacts of NASA/SPoRT Daily Greenness Vegetation Fraction on Land Surface Model and Numerical Weather Forecasts  

NASA Technical Reports Server (NTRS)

The NASA Short-term Prediction Research and Transition (SPoRT) Center has developed a Greenness Vegetation Fraction (GVF) dataset, which is updated daily using swaths of Normalized Difference Vegetation Index data from the Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA EOS Aqua and Terra satellites. NASA SPoRT began generating daily real-time GVF composites at 1-km resolution over the Continental United States (CONUS) on 1 June 2010. The purpose of this study is to compare the National Centers for Environmental Prediction (NCEP) climatology GVF product (currently used in operational weather models) to the SPoRT-MODIS GVF during June to October 2010. The NASA Land Information System (LIS) was employed to study the impacts of the SPoRT-MODIS GVF dataset on a land surface model (LSM) apart from a full numerical weather prediction (NWP) model. For the 2010 warm season, the SPoRT GVF in the western portion of the CONUS was generally higher than the NCEP climatology. The eastern CONUS GVF had variations both above and below the climatology during the period of study. These variations in GVF led to direct impacts on the rates of heating and evaporation from the land surface. In the West, higher latent heat fluxes prevailed, which enhanced the rates of evapotranspiration and soil moisture depletion in the LSM. By late Summer and Autumn, both the average sensible and latent heat fluxes increased in the West as a result of the more rapid soil drying and higher coverage of GVF. The impacts of the SPoRT GVF dataset on NWP was also examined for a single severe weather case study using the Weather Research and Forecasting (WRF) model. Two separate coupled LIS/WRF model simulations were made for the 17 July 2010 severe weather event in the Upper Midwest using the NCEP and SPoRT GVFs, with all other model parameters remaining the same. Based on the sensitivity results, regions with higher GVF in the SPoRT model runs had higher evapotranspiration and lower direct surface heating, which typically resulted in lower (higher) predicted 2-m temperatures (2-m dewpoint temperatures). Portions of the Northern Plains states experienced substantial increases in convective available potential energy as a result of the higher SPoRT/MODIS GVFs. These differences produced subtle yet quantifiable differences in the simulated convective precipitation systems for this event.

Bell, Jordan R.; Case, Jonathan L.; LaFontaine, Frank J.; Kumar, Sujay V.

2012-01-01

187

Seasonal changes in Titan's weather patterns and the evolution and implications of accompanying surface changes  

NASA Astrophysics Data System (ADS)

Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to Titan's low latitudes [1,2]. Observations by Cassini ISS over the ~2 years since the storm revealed most of the changes to be short-lived; only a few darkened patches persisted through Fall 2011. In an unsaturated permeable medium, infiltration rates exceed 20 mm/week [3], so persistence of surface liquids over several months suggests either a shallow impermeable layer or that the local methane table lies close to the surface. Evaporation rates greater than 1 mm/week are predicted in equatorial regions [4] and rates of 20 mm/week have been documented at Titan's poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had liquid ponded to depths of 2.5-50 cm. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match those of clouds or other surface units [6, 7]. Interpretations include cleaning by runoff [2] or deposition of a fine-grained volatile solid as the result of evaporative cooling [6, 7]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, which could constrain rates of evaporation/sublimation of the bright material or re-deposition of darker hydrocarbons by aeolian transport or precipitation from the atmosphere. Cassini and Earth-based observers monitor Titan frequently (typically at least a few times per month), but few clouds have been observed since Fall 2010, which may indicate that enough methane was removed from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a 2004 outburst of south-polar clouds [8], which also appeared to produce significant rainfall [9]. [1] Turtle et al., GRL 38, L03203, doi:10.1029/2010GL046266, 2011. [2] Turtle et al., Science 331, 10.1126/science.1201063. 2011. [3] Hayes et al., GRL 35, L09204, 2008. [4] Schneider et al., Nature 481, doi:10.1038/nature10666, 2012. [5] Hayes et al., Icarus 211, 2011. [6] Barnes et al., LPSC XXXXIII, 2012. [7] Barnes et al., in revision. [8] Schaller et al., Icarus 184, 2006. [9] Turtle et al., GRL 36, L02204, doi:10.1029/2008GL036186, 2009.

Turtle, E. P.; Perry, J.; McEwen, A. S.; Barbara, J. M.; Del Genio, A. D.; West, R. A.; Barnes, J. W.; Hayes, A.; Lorenz, R. D.; Lunine, J. I.; Stofan, E. R.; Schaller, E. L.; Lopes, R. M.; Ray, T. L.

2012-12-01

188

Putting Weather into Weather Derivatives  

NASA Astrophysics Data System (ADS)

Just as weather forecasting has a colorful and often farsighted history within geophysics, financial mathematics has a long and turbulent history within mathematics. Thus it is no surprise that the intersection of real physics and real financial mathematics provides a rich source of problems and insight in both fields. This presentation targets open questions in one such intersection: quantifying ``weather risk.'' There is no accepted (operational) method for including deterministic information from simulation models (numerical weather forecasts, either best guess or by ensemble forecasting methods), into the stochastic framework most common within financial mathematics. Nor is there a stochastic method for constructing weather surrogates which has been proven successful in application. Inasmuch as the duration of employable observations is short, methods of melding short term, medium-range and long term forecasts are needed. On these time scales, model error is a substantial problem, while many methods of traditional statistical practice are simply inappropriate given our physical understanding of the system. A number of specific open questions, along with a smaller number of potential solutions, will be presented. >http://www.maths.ox.ac.uk/~lenny/WeatherRisk

Smith, L. A.; Smith, L. A.

2001-12-01

189

Observations of Ultracool dwarfs with ULTRACAM on the VLT: a search for weather  

E-print Network

We present multi-colour photometry of four field ultracool dwarfs with the triple-beam photometer ultracam. Data were obtained simultaneously in the Sloan-g' band and a specially designed narrow-band NaI filter. The previously reported 1.8-hr period of Kelu-1 is here recovered in the g'-band, but the lack of any significant variability in the NaI light of this object precludes any conclusion as to the cause of the variability. 2MASS 2057-0252 and DENIS 1441-0945 show no convincing evidence for variability. 2MASS 1300+1912, on the other hand, shows good evidence for gradual trends in both bands at the 5% level. These trends are anti-correlated at a high level of significance, a result which is incompatible with models of starspot-induced variability. It would seem likely that dust cloud "weather" is responsible for the short-term variability in this object.

S. P. Littlefair; V. S. Dhillon; T. R. Marsh; T. Shahbaz; E. L. Martin

2006-05-09

190

On one approach to space weather studies from ground based observations  

NASA Astrophysics Data System (ADS)

The term ,,Space Weather" is related to various physical parameters in the surrounding of the Earth with the impact on technological systems and the health. Their variability is primary controlled by the solar activity. Here we use two types of ground based measurements. To characterize the solar activity we use an intensity of the monochromatic coronal emission line Fe XIV (530.3 nm), and, as a measure of this response of the solar activity near the Earth are used measurements of cosmic rays by neutron monitors at different cutoff rigidities. Comparison of the monthly mean indices derived from those measurements revealed the high mutual correlation. Both types of measurements as well as the derived indices are discussed. From coronal measurements the coronal index of solar activity and the size of polar coronal holes are derived, while from neutron monitor measurements the difference between variations at high and low latitudes is used as an index. The time series of both indices are constructed on the daily basis and compared as well. There is an indication that measurements above the E-limb of the Sun are useful for the prediction of cosmic ray flux at the energies of neutron monitors about 10 days ahead. Physical relationship between the green corona and cosmic rays is discussed.

Minarovjech, A.; Rusin, V.; Rybansky, M.; Kudela, K.; Kollar, V.

191

Schoolyard BioBlitz: Monthly Observations of Plants, Insects, Weather, the Sun and Moon  

NSDL National Science Digital Library

In this field lab students will go outside and observe a particular area of the schoolyard. Students will design investigations to complete outside and will use outdoor observations to provide evidence for our indoor activities.

Alissa Naymark

192

Surface water vapor exchanges on the Greenland ice sheet derived from automated weather station data  

NASA Astrophysics Data System (ADS)

Greenland Climate Network (GC-Net) meteorological observations are used to estimate surface water vapor exchanges at Greenland ice sheet sites and for the ice sheet as a whole for the period of mid 1995 to mid 2000. Water vapor fluxes were derived using aerodynamic profile methods and validated with eddy correlation and evaporation pan measurements. A net water vapor flux to the atmosphere predominates in summer below 2000 m elevation sites. The net water vapor flux is -87 +/- 30 mm y-1 water equivalence in the Jakobshavn ablation region at 962 m elevation and -74 +/- 26 mm y-1 at equilibrium line altitude (1150 m) 17 km up-glacier. Net deposition is observed at an undulation trough site, whereas at the adjacent crest site, 6 km away, net water vapor loss is observed. At high elevation sites, the annual water vapor flux is towards the surface, approximately +15 mm y-1. Comparison of monthly values with output from the NCAR Mesoscale Model (MM5) indicate that the month to month variability is well reproduced; yet the magnitude is underestimated by as much as 150%. Based on a trend surface regression of the temperature lapse rate along the slope, elevation, and latitude, a Greenland ice sheet annual net total water vapor flux of -7.34 +/- 4.4 x 1013 kg y-1 is derived. This estimates is similar to the result of -6.18 x 1013 kg y-1 [ Ohmura et al., 1999] based on atmospheric modeling. The precipitation loss is estimated to be 14%, given an ice sheet accumulation estimate of 5.90 x 1014 kg y-1 by Ohmura et al. [1999]. Annual blowing snow sublimation is estimated using a bulk snow transport formulation and a conceptual model of maximum blowing snow transport distance. The actual blowing snow transport is estimated using potential transport calculations derived from wind speed records and a snow availability factor derived from air temperature and surface height measurements. Blowing snow sublimation rates are estimated to be as great as 500 mm y-1 at sites with strongest winds.

Box, Jason Eric

193

Evolution of Titan's equinoctial weather patterns and accompanying surface changes and implications thereof  

NASA Astrophysics Data System (ADS)

Post-equinox changes in Titan's atmospheric circulation brought clouds and extensive methane rain to Titan's low latitudes [1,2]. Observations by Cassini ISS over the ~1.5 years since the storm revealed most of the changes to be short-lived; only a few darkened patches persisted through Fall 2011. In an unsaturated permeable medium, infiltration rates are >20 mm/week [3], so persistence of surface liquids over several months suggests either a shallow impermeable layer or that the local methane table lies close to the surface. Evaporation rates >1 mm/week are predicted in equatorial regions [4] and rates of 20 mm/week have been documented at the poles [5], thus areas where darkening persisted must be saturated ground at the level of a methane table or have had liquid ponded to depths of 2.5-50 cm. Several smaller areas of surface brightening were also observed, a phenomenon that is less well understood. Cassini VIMS spectra of these regions do not match those of clouds or other surface units [6, 7]. Interpretations include cleaning by runoff [2] or deposition of fresh methane ice [6, 7]. In general, brightening has persisted longer than darkening, but these areas are also reverting to their original appearance, which could constrain the rate of re-deposition of darker hydrocarbon materials by aeolian transport or possibly precipitation of aerosols from the atmosphere. Although we monitor Titan frequently (at least a few times per month), little cloud activity has been observed since Fall 2010. This lack of clouds may indicate that the outbreak removed enough methane from the atmosphere and the lapse rate stabilized sufficiently that activity will not resume until the onset of convection at mid-northern latitudes later in northern spring. A similar lapse followed a large outbreak of south-polar clouds in Fall 2004 [8], which also appeared to produce significant rainfall [9]. References: [1] Turtle et al., GRL 38, L03203, doi: 10.1029/2010GL046266, 2011. [2] Turtle et al., Science 331, p. 1414, 10.1126/science.1201063. 2011. [3] Hayes et al., GRL 35, L09204, 2008. [4] Schneider et al., Nature 481, doi:10.1038/nature10666, 2012. [5] Hayes et al., Icarus 211, p. 655, 2011. [6] Barnes et al., LPSC XXXXIII, 2012. [7] Barnes et al., Titan Through Time, 3-5 April 2012. [8] Schaller et al., Icarus 184, p. 517, 2006. [9] Turtle et al., GRL 36, L02204, doi:10.1029/ 2008GL036186, 2009.

Turtle, E. P.; Perry, J. E.; Barnes, J. W.; McEwen, A. S.; Barbara, J. M.; Del Genio, A. D.; Hayes, A. G.; West, R. A.; Lorenz, R. D.; Schaller, E. L.; Lunine, J. I.; Ray, T. L.; Lopes, R. M. C.; Stofan, E. R.

2012-04-01

194

Space Weathering of Rocks  

NASA Technical Reports Server (NTRS)

Space weathering discussions have generally centered around soils but exposed rocks will also incur the effects of weathering. On the Moon, rocks make up only a very small percentage of the exposed surface and areas where rocks are exposed, like central peaks, are often among the least space weathered regions we find in remote sensing data. However, our studies of weathered Ap 17 rocks 76015 and 76237 show that significant amounts of weathering products can build up on rock surfaces. Because rocks have much longer surface lifetimes than an individual soil grain, and thus record a longer history of exposure, we can study these products to gain a deeper perspective on the weathering process and better assess the relative impo!1ance of various weathering components on the Moon. In contrast to the lunar case, on small asteroids, like Itokowa, rocks make up a large fraction of the exposed surface. Results from the Hayabusa spacecraft at Itokowa suggest that while the low gravity does not allow for the development of a mature regolith, weathering patinas can and do develop on rock surfaces, in fact, the rocky surfaces were seen to be darker and appear spectrally more weathered than regions with finer materials. To explore how weathering of asteroidal rocks may differ from lunar, a set of ordinary chondrite meteorites (H, L, and LL) which have been subjected to artificial space weathering by nanopulse laser were examined by TEM. NpFe(sup 0) bearing glasses were ubiquitous in both the naturally-weathered lunar and the artificially-weathered meteorite samples.

Noble, Sarah

2011-01-01

195

Low cloud type over the ocean from surface observations. Part 1: Relationship to surface meteorology and the vertical distribution of temperature and moisture  

SciTech Connect

Surface cloud observations and coincident surface meteorological observations and soundings from five ocean weather stations are used to establish representative relationships between low cloud type and marine boundary layer (MBL) properties for the subtropics and midlatitudes by compositing soundings and meteorological observations for which the same low cloud type was observed. Physically consistent relationships are found to exist between low cloud type, MBL structure, and surface meteorology at substantially different geographical locations and seasons. Relative MBL height and inferred decoupling between subcloud and cloud layers are increasingly greater for stratocumulus, cumulus-under-stratocumulus, and cumulus, respectively, at midlatitude locations as well as the eastern subtropical location during both summer and winter. At the midlatitude locations examined, cloudiness identified as fair-weather stratus often occurs in a deep, stratified cloud layer with little or no capping inversion. This strongly contrasts with cloudiness identified as stratocumulus, which typically occurs in a relatively well-mixed MBL under a strong capping inversion at both midlatitude and eastern subtropical locations. At the transition between subtropics and midlatitudes in the western North Pacific, cloudiness identified as fair-weather stratus occurs in a very shallow layer near the surface. Above this layer the associated profile of temperature and moisture is similar to that for cumulus at the same location, and neither of these cloud types is associated with a discernible MBL. Sky-obscuring fog and observations of no low cloudiness typically occur with surface-based inversions. These observed relationships can be used in future studies of cloudiness and cloudiness variability to infer processes and MBL structure where above-surface observations are lacking. 42 refs., 6 figs., 4 tabs.

Norris, J.R. [Univ. of Washington, Seattle, WA (United States)] [Univ. of Washington, Seattle, WA (United States)

1998-03-01

196

Annual carbon dioxide cycle in a montane soil: observations, modeling, and implications for weathering  

Microsoft Academic Search

Profiles of COâ concentrations in soil and snow, soil respiration, soil and snow temperatures, and shallow ground water chemistry were monitored from March 1984 to July 1985 in a montane region neat Brighton, Utah. Significant seasonal variations in the concentrations of COâ in soil and snow occurred, and two principal rise-decline cycles were observed. During the first cycle the concentration

D. Kip Solomon; Thure E. Cerling

1987-01-01

197

Optimal Sites for Supplementary Weather Observations: Simulation with a Small Model  

Microsoft Academic Search

Anticipating the opportunity to make supplementary observations at locations that can depend upon the currentweather situation, the question is posed as to what strategy should be adopted to select the locations, if thegreatest improvement in analyses and forecasts is to be realized. To seek a preliminary answer, the authorsintroduce a model consisting of 40 ordinary differential equations, with the dependent

Kerry Emanuel; Edward Lorenz

1997-01-01

198

On the Relationship Between the Effects of Targeted Weather Observations and Local Low Dimensionalities in the Atmosphere  

NASA Astrophysics Data System (ADS)

Recently, the concept of targeting weather observations has been tested by idealized model experiments and by deploying dropsonde observations from aircraft in Northern Hemisphere winter field programs. While the evaluation studies have so far provided convincing empirical evidence that targeting observations is an operationally attainable way to improve forecasts, the exact dynamical mechanisms through which targeted observations realize their beneficial forecast effects have not yet been explored. The main differences between the targeting strategies proposed by the different teams are in the algorithms used to select to locations of the added observations. Nevertheless, there is one common element of these techniques; they are all linear inferences applied to a set of numerical forecasts. The main goal of this paper is to investigate why methods based on such a strong assumption can have skill in determining the optimal locations of the added observations. It will be argued that regions of local low dimensionality of the unstable subspace in the atmosphere (Patil et al., 2001) play an important role in the success of targeting. The above goal is achieved by first generating a large experimental ensemble of forecasts using the T62 horizontal resolution version of the operational global model of the National Centers for Environmental Prediction (NCEP). A one month case study associated with the 2000 Winter Reconnaissance Program (Szunyogh et al. 2001) is prepared. Then the regions of local low dimensionality are determined. The relationship between locations of these regions, the local energetics of the baroclinic wave packets, and the propagation of the influence of the added observations is explored. >http://www.math.umd.edu/~dap/chaos_atmos.html

Zimin, A.; Szunyogh, I.; Patil, D.; Kalnay, E.; Yorke, J.; Hunt, B.; Ott, E.

2001-12-01

199

Doppler weather radar observations of the 2009 eruption of Redoubt Volcano, Alaska  

USGS Publications Warehouse

The U.S. Geological Survey (USGS) deployed a transportable Doppler C-band radar during the precursory stage of the 2009 eruption of Redoubt Volcano, Alaska that provided valuable information during subsequent explosive events. We describe the capabilities of this new monitoring tool and present data captured during the Redoubt eruption. The MiniMax 250-C (MM-250C) radar detected seventeen of the nineteen largest explosive events between March 23 and April 4, 2009. Sixteen of these events reached the stratosphere (above 10 km) within 2–5 min of explosion onset. High column and proximal cloud reflectivity values (50 to 60 dBZ) were observed from many of these events, and were likely due to the formation of mm-sized accretionary tephra-ice pellets. Reflectivity data suggest that these pellets formed within the first few minutes of explosion onset. Rapid sedimentation of the mm-sized pellets was observed as a decrease in maximum detection cloud height. The volcanic cloud from the April 4 explosive event showed lower reflectivity values, due to finer particle sizes (related to dome collapse and related pyroclastic flows) and lack of significant pellet formation. Eruption durations determined by the radar were within a factor of two compared to seismic and pressure-sensor derived estimates, and were not well correlated. Ash dispersion observed by the radar was primarily in the upper troposphere below 10 km, but satellite observations indicate the presence of volcanogenic clouds in the stratosphere. This study suggests that radar is a valuable complement to traditional seismic and satellite monitoring of explosive eruptions.

Schneider, David J.; Hoblitt, Richard P.

2013-01-01

200

Weather Watch  

ERIC Educational Resources Information Center

Suggests a number of ways in which Federal Aviation Agency weather report printouts can be used in teaching the weather section of meteorology. These weather sequence reports can be obtained free of charge at most major airports. (JR)

Bratt, Herschell Marvin

1973-01-01

201

Coastal Observations of Weather Features in Senegal during the AMMA SOP-3 Period  

NASA Technical Reports Server (NTRS)

During 15 August through 30 September 2006, ground and aircraft measurements were obtained from a multi-national group of students and scientists in Senegal. Key measurements were aimed at investigating and understanding precipitation processes, thermodynamic and dynamic environmental conditions, cloud, aerosol and microphysical processes and spaceborne sensors (TRMM, CloudSat/Calipso) validation. Ground and aircraft instruments include: ground based polarimetric radar, disdrometer measurements, a course and a high-density rain gauge network, surface chemical measurements, a 10 m flux tower, broadband IR, solar and microwave measurements, rawinsonde and radiosonde measurements, FA-20 dropsonde, in situ microphysics and cloud radar measurements. Highlights during SOP3 include ground and aircraft measurements of squall lines, African Easterly Waves (AEWs), Saharan Air Layer advances into Senegal, and aircraft measurements of AEWs -- including the perturbation that became Hurricane Isaac.

Jenkins, G.; Kucera, P.; Joseph, E.; Fuentes, J.; Gaye, A.; Gerlach, J.; Roux, F.; Viltard, N.; Papazzoni, M.; Protat, A.; Bouniol, D.; Reynolds, A.; Arnault, J.; Badiane, D.; Kebe, F.; Camara, M.; Sall, S.

2009-01-01

202

The large-scale spatio-temporal variability of precipitation over Sweden observed from the weather radar network  

NASA Astrophysics Data System (ADS)

Using measurements from the national network of 12 weather radar stations for the last decade (2000-2010), we investigate the large-scale spatio-temporal variability of precipitation over Sweden. These statistics provide useful information to evaluate regional climate models as well as for hydrology and energy applications. A strict quality control is applied to filter out noise and artifacts from the radar data. We focus on investigating four distinct aspects namely, the diurnal cycle of precipitation and its seasonality, the dominant time scale (diurnal vs. seasonal) of variability, precipitation response to different wind directions, and the correlation of precipitation events with the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). When classified based on their intensity, moderate to high intensity events (precipitation > 0.34 mm (3 h)-1) peak distinctly during late afternoon over the majority of radar stations in summer and during late night or early morning in winter. Precipitation variability is highest over the southwestern parts of Sweden. It is shown that the high intensity events (precipitation > 1.7mm (3 h)-1) are positively correlated with NAO and AO (esp. over northern Sweden), while the low intensity events are negatively correlated (esp. over southeastern parts). It is further observed that southeasterly winds often lead to intense precipitation events over central and northern Sweden, while southwesterly winds contribute most to the total accumulated precipitation for all radar stations. Apart from its operational applications, the present study demonstrates the potential of the weather radar data set for studying climatic features of precipitation over Sweden.

Devasthale, A.; Norin, L.

2013-12-01

203

The large-scale spatio-temporal variability of precipitation over Sweden observed from the weather radar network  

NASA Astrophysics Data System (ADS)

Using measurements from the national network of 12 weather radar stations for the 11-year period 2000-2010, we investigate the large-scale spatio-temporal variability of precipitation over Sweden. These statistics provide useful information to evaluate regional climate models as well as for hydrology and energy applications. A strict quality control is applied to filter out noise and artifacts from the radar data. We focus on investigating four distinct aspects: the diurnal cycle of precipitation and its seasonality, the dominant timescale (diurnal versus seasonal) of variability, precipitation response to different wind directions, and the correlation of precipitation events with the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). When classified based on their intensity, moderate- to high-intensity events (precipitation > 0.34 mm/3 h) peak distinctly during late afternoon over the majority of radar stations in summer and during late night or early morning in winter. Precipitation variability is highest over the southwestern parts of Sweden. It is shown that the high-intensity events (precipitation > 1.7 mm/3 h) are positively correlated with NAO and AO (esp. over northern Sweden), while the low intensity events are negatively correlated (esp. over southeastern parts). It is further observed that southeasterly winds often lead to intense precipitation events over central and northern Sweden, while southwesterly winds contribute most to the total accumulated precipitation for all radar stations. Apart from its operational applications, the present study demonstrates the potential of the weather radar data set for studying climatic features of precipitation over Sweden.

Devasthale, A.; Norin, L.

2014-06-01

204

Observations of electrons at the lunar surface  

Microsoft Academic Search

Observations of electrons at the Apollo 12 and 15 sites by the Alsep Solar Wind Spec- trometer experiments showed qualitative differehces. In the geomagnetic tail the Apollo 15 instrument provided measurements of lunar photoelectron flux from 5 to 40 eV; at 20 eV the flux was 2 X 106 el.\\/cm a sec eV ster. The estimated height-integrated conductivity of th

Bruce E. Goldstein

1974-01-01

205

Natural Weathering Rates of Silicate Minerals  

NASA Astrophysics Data System (ADS)

Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic activities. For example, Huntington et al. (2000) show that extensive timber harvesting in the southeastern forests of the United States, which are underlain by intensely weathered saprolites, produces net calcium exports that exceed inputs from weathering, thus creating a long-term regional problem in forest management.The role of chemical weathering has long been recognized in economic geology. Tropical bauxites, which account for most of world's aluminum ores, are typical examples of residual concentration of silicate rocks by chemical weathering over long time periods (Samma, 1986). Weathering of ultramafic silicates such as peridotites forms residual lateritic deposits that contain significant deposits of nickel and cobalt. Ores generated by chemical mobilization include uranium deposits that are produced by weathering of granitic rocks under oxic conditions and subsequent concentration by sorption and precipitation ( Misra, 2000).Over the last several decades, estimating rates of silicate weathering has become important in addressing new environmental issues. Acidification of soils, rivers, and lakes has become a major concern in many parts of North America and Europe. Areas at particular risk are uplands where silicate bedrock, resistant to chemical weathering, is overlain by thin organic-rich soils (Driscoll et al., 1989). Although atmospheric deposition is the most important factor in watershed acidification, land use practices, such as conifer reforestation, also create acidification problems ( Farley and Werritty, 1989). In such environments, silicate hydrolysis reactions are the principal buffer against acidification. As pointed out by Drever and Clow (1995), a reasonable environmental objective is to decrease the inputs of acidity such that they are equal to or less than the rate of neutralization by weathering in sensitive watersheds.The intensive interest in past and present global climate change has renewed efforts to understand quantitatively feedback mechanisms between climate and chemical weathering. On timescales longer than

White, A. F.

2003-12-01

206

NOAA Daily Weather Maps  

NSDL National Science Digital Library

The charts on this website are the principal charts of the former Weather Bureau publication, "Daily Weather Map." They are the Surface Weather Map, the 500-Millibar Height Contours chart, the Highest and Lowest Temperatures chart, and the Precipitation Areas and Amounts chart. For each day, simple charts are arranged on a single page. These charts are the surface analysis of pressure and fronts, color shading, in ten degree intervals,of maximum and minimum temperature, 500-Millibar height contours, and color shaded 24-hour total precipitation. These charts act as links to their respective Daily Weather Map charts. All charts are derived from the operational weather maps prepared at the National Centers for Environmental Prediction, Hydrometeorological Prediction Center, National Weather Service.

Hydrometeorological Prediction Center

2011-01-01

207

Weather Stations: Phase Change  

NSDL National Science Digital Library

In this activity, learners observe the water cycle in action! Water vapor in a tumbler condenses on chilled aluminum foil — producing the liquid form of water familiar to us as rain and dew. Learners discuss how Jupiter's lack of a surface simplifies its water cycle. Learners then consider the roles ammonia and ammonia compounds play in Jupiter's more complicated atmosphere. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

2014-07-11

208

Comparisons of Surface Meteorology and Turbulent Heat Fluxes over the Atlantic: NWP Model Analyses versus Moored Buoy Observations  

Microsoft Academic Search

Surface meteorological variables and turbulent heat fluxes in the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalyses 1 and 2 (NCEP1 and NCEP2) and the analysis from the operational system of the European Centre for Medium-Range Weather Forecasts (ECMWF) are compared with high-quality moored buoy observations in regions of the Atlantic including the eastern North Atlantic, the coastal

Bomin Sun; Lisan Yu; Robert A. Weller

2003-01-01

209

Land Surface Hydrological Processes: Remote Sensing Observations and  

E-print Network

Group 2 The gap between land surface observation and modeling enlarges as the new measuring methods (e describes several recent and ongoing efforts to bridge the gap between land surface observationsReflectance Water Bare Soil Grassland Wood AVHRR MODIS Landsat GRACETRMM Clouds Thermal emission NDVI LAI Land cover

Washington at Seattle, University of

210

Plasmon Surface Polariton Dispersion by Direct Optical Observation.  

ERIC Educational Resources Information Center

Describes several simple experiments that can be used to observe directly the dispersion curve of plasmon surface polaritons (PSP) on flat metal surfaces. A method is described of observing the increonental change in the wave vector of the PSP due to coatings that differ in thickness by a few nanometers. (Author/CS)

Swalen, J. D.; And Others

1980-01-01

211

Space Weathering of Lunar Rocks  

NASA Technical Reports Server (NTRS)

All materials exposed at the lunar surface undergo space weathering processes. On the Moon, boulders make up only a small percentage of the exposed surface, and areas where such rocks are exposed, like central peaks, are often among the least space weathered regions identified from remote sensing data. Yet space weathered surfaces (patina) are relatively common on returned rock samples, some of which directly sample the surface of larger boulders. Because, as witness plates to lunar space weathering, rocks and boulders experience longer exposure times compared to lunar soil grains, they allow us to develop a deeper perspective on the relative importance of various weathering processes as a function of time.

Noble, S. K.; Keller, L. P.; Christoffersen, R.; Rahman, Z.

2012-01-01

212

External Resource: Erosion and Weathering  

NSDL National Science Digital Library

This is a Teachers' Domain photo essay with images that depict surface features on Earth that result from weathering and erosion, as well as measures designed to mitigate their unwanted effects. Topics: weathering, erosion, sediments, dunes, deltas, glaci

1900-01-01

213

Observed near-surface currents under high wind speeds  

NASA Astrophysics Data System (ADS)

From the Surface Velocity Program (SVP) drifter current and QuikSCAT wind data, the relationship between the observed near-surface current vectors and surface wind vectors for the northwestern Pacific Ocean under high winds (20-50 m s-1) are obtained with quantitative estimations of near-surface drift ratio (current speed versus wind speed)r(˜2%) and near-surface drift angle? (˜0°-10° to the right of the winds). These estimations keep unchanged after removing the surface geostrophic component. From the SVP drifter current and daily WindSat wind data, the estimated ris still approximately 2%. Three linear regression equations are obtained between the observed near-surface current speeds and the surface wind stress for the high wind range.

Chang, Y.-C.; Chen, G.-Y.; Tseng, R.-S.; Centurioni, L. R.; Chu, Peter C.

2012-11-01

214

A Dozen Years of Temperature Observations at the Summit: Central Greenland Automatic Weather Stations 1987-99.  

NASA Astrophysics Data System (ADS)

On 4 May 1987, the first automatic weather station (AWS) near the summit of the Greenland Ice Sheet began transmitting data. Air temperature records from this site, AWS Cathy, as well as nearby AWS at the Greenland Ice Sheet Project II (GISP2, now Summit) camp have been combined with Special Sensor Microwave Imager brightness temperature data to create a composite temperature history of the Greenland summit. This decadal-plus-length (4536 days) record covers the period from May 1987 to October 1999 and continues currently. The record is derived primarily from near-surface temperature data from AWS Cathy (May 1987-May 1989), AWS GISP2 (June 1989-November 1996), and AWS Summit (May 1996 and continuing). Despite the 35-km distance between them, the AWS Cathy data have been converted to the equivalent basis of temperatures from the AWS GISP2 and AWS Summit locations. The now completed `Summit' temperature time series represents a unique record that documents a multiyear temperature recovery after the eruption of Mt. Pinatubo in June 1991 and that initiates a baseline needed for climate change detection.

Shuman, Christopher A.; Steffen, Konrad; Box, Jason E.; Stearns, Charles R.

2001-04-01

215

Understanding the assimilation of dual-polarimetric radar observations and their impact on convective weather forecasting in mesoscale models  

NASA Astrophysics Data System (ADS)

Dual-polarimetric radars typically transmit/receive both horizontally and vertically polarized radio wave pulses. Owing to the enhanced measurement, dual-pol Doppler variables can provide more information about the liquid and solid cloud and precipitation particles, hence obtain more accurate estimate of rainfall and hydrometeors than non-polarimetric weather radars. The assimilation of dual-pol radar data may be a potential way to improve the performance of short-term forecast of numerical models. At present, not much effort has been given into the dual-pol radar data assimilation research field. With the ongoing upgrade of the current U.S. NEXRAD radar network to include dual-polarimetric capabilities, the dual-pol radar network will cover the whole country within the next couple years. The time is upon us to begin exploring how to best use the polarimetric data to improve forecast of severe storm and forecast initialization. The assimilation of dual-pol data for real cases is a challenging work. In this study, high-resolution (~1 km) WRF model and its 3DVAR data assimilation system are used. The dual-polarimetric radar data used in our studies was collected by the C-band Advanced Radar for Meteorological and Operational Research (ARMOR) radar (located at Huntsville International Airport (34.6804N, 86.7743W)), yet the emphasis now is toward using S-Band data from the upgraded NEXRAD network. Our presentation will highlight our recent work on assimilating the ARMOR radar data for real case convective storms, as well as new work using S-Band observations. Details of the methodology of data assimilation, the influences of different dual-pol variables on model initial condition and on the short-term prediction of precipitation, and the results for the real case storms, will be presented. In addition, before including a new observing system in an assimilation system, (dual-pol observations in this case) it is important to first assess the information content and uncertainty of the observations and forward model. An estimate of the information content in a set of observations requires knowledge of the relationship between measurements and forward observations. If the range of possible values of the measurements and forward observations is represented as a probability distribution, then the information content can be computed from the joint probability density function of the forward observations conditioned on the set of available measurements and on whatever forward model is chosen to relate them. Preliminary results will be shown toward understanding the information content of dual-polarimetric radar observations and their relationship to WRF model physics uncertainty.

Li, X.; Mecikalski, J. R.; Posselt, D. J.

2011-12-01

216

Understanding the coupled surface energy flux-valley wind system using observations in an alpine valley  

NASA Astrophysics Data System (ADS)

Buoyancy-driven diurnal valley winds depend on relative partitioning of incoming solar radiation into the sensible and latent heat fluxes. Evaporation and transpiration at the surface contribute to the latent heat flux, while heating of the air near the surface results from the sensible heat flux. Thus if more moisture is available at the surface, (e.g. as soil moisture or dew) then more energy will be partitioned into the latent heat flux, and less will be available for the sensible heat flux. Presented here is an analysis of observations from surface weather stations placed throughout the La Fouly catchment (~20 km^2) in southern Switzerland during the summers of 2009 and 2010. The stations were equipped with sensors to measure atmospheric and land surface variables including: incoming solar radiation, 2 m air temperature, skin temperature, wind speed and direction, relative humidity, precipitation, soil moisture, and soil temperature. Scaling analysis is used to show how the balance between sensible and latent heat fluxes influences the buoyancy-driven valley winds. A preliminary analysis indicates that increased surface soil moisture tends to decrease the strength of slope winds both during the day and at night, while decreased soil moisture has the opposite effect. While this type of relation has been previously investigated through numerical simulations of valley or slope flows, it has not (to the authors' knowledge), been previously observed in the field.

Daniels, M. H.; Pardyjak, E.; Brutsaert, W. H.; Mage, R.; Parlange, M. B.

2010-12-01

217

Modelling Glacier Surface Temperature Using Weather Station Data and Historical Climate Reconstructions  

Microsoft Academic Search

Models of glacier response to climate change and snow\\/ice melt require knowledge of air temperatures at the glacier surface. This can be directly measured at selected locations, but distributed models of glacier melt require temperature information over an entire surface. Furthermore, in many practical applications, temperature must be estimated for locations where no data is available. A new and more

N. Schaffer; S. J. Marshall

2009-01-01

218

NPP VIIRS Land Surface Temperature EDR validation using NOAA's observation networks  

NASA Astrophysics Data System (ADS)

NOAA will soon use the new Visible Infrared Imager Radiometer Suite (VIIRS) on the Joint Polar Satellite System (JPSS) as its primary polar-orbiting satellite imager. Employing a near real-time processing system, NOAA will generate a series of Environmental Data Records (EDRs) from VIIRS data. For example, the VIIRS Land Surface Temperature (LST) EDR will estimate the surface skin temperature over all global land areas and provide key information for monitoring Earth surface energy and water fluxes. Because both VIIRS and its processing algorithms are new, NOAA is conducting a rigorous calibration and validation program to understand and improve product quality. This work presents a new validation methodology to estimate the quantitative uncertainty in the LST EDR, and contribute to improving the retrieval algorithm. It employs a physically-based approach to scaling up point LST measurements currently made operationally at many field and weather stations around the world. The scaling method consists of the merging information collected at different spatial resolutions within a land surface model to fully characterize large area (km x km scale) satellite products. The approach can be used to explore scaling issues over terrestrial surfaces spanning a large range of climate regimes and land cover types, including forests and mixed vegetated areas. First results show that VIIRS and MODIS (collection 5) LST products are very consistent. Over vegetated areas, VIIRS LST EDRs verify JPSS program quality requirements - bias and precision specifications of VIIRS LST EDRs are 1.5K and 2.5K. However, VIIRS agrees better with scaled-up field data than with non-scaled field observations. Over desert areas, current VIIRS LST EDRs do not verify JPSS specifications. VIIRS and MODIS LST products tend to underestimate surface temperature at night. Ultimately, this validation approach should lead to an accurate and continuously-assessed VIIRS LST products suitable to support weather forecast, hydrological applications, or climate studies. It is readily adaptable to other moderate resolution satellite systems.

Guillevic, P. C.; Privette, J. L.

2012-12-01

219

How Do Meteorologists Forecast the Weather?  

NSDL National Science Digital Library

This is a lesson that I developed where students learn how meteorologists predict the weather. Students will use surface weather maps, radar, satellite, and weather models from the National Weather Service to assess the current state of the weather and make a prediction.

David Faysash

2012-07-30

220

Weather Forecasting  

NSDL National Science Digital Library

Students consider how weather forecasting plays an important part in their daily lives. They learn about the history of weather forecasting — from old weather proverbs to modern forecasting equipment — and how improvements in weather technology have saved lives by providing advance warning of natural hazards.

Integrated Teaching and Learning Program,

221

UM Weather  

NSDL National Science Digital Library

Sponsored by The Weather Underground at the University of Michigan at Ann Arbor, UM Weather bills itself as the "Internet's premier source of weather information." The site offers several general audience tools such as the Fast Forecast for any city in the US, ski weather, and weather cams. But, it also provides access to over two dozen weather software packages, a new computer model forecasts page, and most impressively a list of close to 400 other weather related Web sites. Professionals and researchers will appreciate the non-technical feel of the site and the valuable information they can procure from it.

222

Winter Weather  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Weather affects our everyday lives. Some days it's sunny and some days its not. The years weather is split up into seasons. 1. What are the four seasons? 2. What kind of weather do you see in the summer? 3. What kind of weather is unique to winter? 4. ...

Mrs. Bellows

2009-09-28

223

SEM and TEM Observation of the Surfaces of the Fine-Grained Particles Retrieved from the Muses-C Regio on the Asteroid 25413 Itokawa  

NASA Technical Reports Server (NTRS)

Surface materials on airless solar system bodies exposed to interplanetary space are gradually changed their visible to near-infrared reflectance spectra by the process called "space weathering", which makes the spectra darker and redder. Hapke et al. proposed a model of space weathering: vapor deposition of nanophase reduced iron (npFe(sup 0)) on the surfaces of the grains within the very surface of lunar regolith. This model has been proved by detailed observation of the surfaces of the lunar soil grains by transmission electron microscope (TEM). They demonstrated that npFe(sup 0) was formed by a combination of vapor deposition and irradiation effects. In other words, both micrometeorite impacts and irradiation by solar wind and galactic cosmic ray play roles on the space weathering on the Moon. Because there is a continuum of reflectance spectra from those of Q-type asteroids (almost the same as those of ordinary chondrites) to those of S-type asteroids, it is strongly suggested that reflectance spectra of asteroids composed of ordinary chondrite-like materials were modified over time to those of S-type asteroids due to space weathering. It is predicted that a small amount of npFe(sup 0) on the surface of grains in the asteroidal regolith composed of ordinary chondrite-like materials is the main agent of asteroidal space weathering.

Noguchi, T.; Nakamura, T.; Zolensky, Michael E.; Tanaka, M.; Hashimoto, T.; Konno, M.; Nakato, A.; Ogami, T.; Fujimura, A.; Abe, M.; Yada, T.; Mukai, T.; Ueno, M.; Okada, T.; Shirai, K.; Ishibashi, Y.; Okazaki, R.

2011-01-01

224

Direct observation of chemical bond dynamics on surfaces.  

PubMed

The dynamics of chemisorbed species as they swing to-and-fro on their adsorption sites may be directly observed with electron-stimulated desorption. The observation of the thermal disorder in adsorbate chemical bond directions, through studies of the thermal excitation of librational modes, allows one to visualize the potential energy surfaces controlling the structure and dynamics of adsorbates on single crystal metal and semiconductor surfaces. This information may be useful in understanding surface diffusion as well as the spatial aspects of surface chemical reactions. PMID:17801228

Yates, J T; Alvey, M D; Dresser, M J; Henderson, M A; Kiskinova, M; Ramsier, R D; Szabó, A

1992-03-13

225

Observation of Fermi arc surface states in a topological metal.  

PubMed

The topology of the electronic structure of a crystal is manifested in its surface states. Recently, a distinct topological state has been proposed in metals or semimetals whose spin-orbit band structure features three-dimensional Dirac quasiparticles. We used angle-resolved photoemission spectroscopy to experimentally observe a pair of spin-polarized Fermi arc surface states on the surface of the Dirac semimetal Na3Bi at its native chemical potential. Our systematic results collectively identify a topological phase in a gapless material. The observed Fermi arc surface states open research frontiers in fundamental physics and possibly in spintronics. PMID:25593189

Xu, Su-Yang; Liu, Chang; Kushwaha, Satya K; Sankar, Raman; Krizan, Jason W; Belopolski, Ilya; Neupane, Madhab; Bian, Guang; Alidoust, Nasser; Chang, Tay-Rong; Jeng, Horng-Tay; Huang, Cheng-Yi; Tsai, Wei-Feng; Lin, Hsin; Shibayev, Pavel P; Chou, Fang-Cheng; Cava, Robert J; Hasan, M Zahid

2015-01-16

226

Global chemical weather forecasts for field campaign planning: predictions and observations of large-scale features during MINOS, CONTRACE, and INDOEX  

NASA Astrophysics Data System (ADS)

The first global tropospheric forecasts of O3 and its precursors have been used in the daily flight planning of field measurement campaigns. The 3-D chemistry-transport model MATCH-MPIC is driven by meteorological data from a weather center (NCEP) to produce daily 3-day forecasts of the global distributions of O3 and related gases, as well as regional CO tracers. This paper describes the forecast system and its use in three field campaigns, MINOS, CONTRACE and INDOEX. An overview is given of the forecasts by MATCH-MPIC and by three other chemical weather forecast models (EURAD, ECHAM, and FLEXPART), focusing on O3 and CO. Total CO and regional CO tracers were found to be the most valuable gases for flight planning, due to their relatively well-defined anthropogenic source regions and lifetimes of one to a few months. CO was in good agreement with the observations on nearly all the flights (generally r > 0.7, RMS < 20%). In every case in which the chemical weather forecasts were primarily responsible for the flight plans, the targeted features were observed. Two forecasted phenomena are discussed in detail: outflow from Asia observed in the Mediterranean upper troposphere during MINOS, and outflow from North America observed in the middle troposphere over northern Europe during CONTRACE. It is shown that although such pollution plumes occur repeatedly during the months around the campaigns, their frequency is sufficiently low (~10--30% of the time) that global chemical weather forecasts are important for enabling them to be observed during limited-duration field campaigns. The MATCH-MPIC chemical weather forecasts, including an interface for making customized figures from the output, are available for community use via http://www.mpch-mainz.mpg.de/~lawrence/forecasts.html .

Lawrence, M. G.; Rasch, P. J.; von Kuhlmann, R.; Williams, J.; Fischer, H.; de Reus, M.; Lelieveld, J.; Crutzen, P. J.; Schultz, M.; Stier, P.; Huntrieser, H.; Heland, J.; Stohl, A.; Forster, C.; Elbern, H.; Jakobs, H.; Dickerson, R. R.

2002-10-01

227

Ground Effects of Space Weather  

Microsoft Academic Search

Space storms produce geomagnetically induced currents (GIC) in technological systems at the Earth’s surface, such as electric\\u000a power transmission grids, pipelines, communication cables and railways. Thus GIC are the ground end of the space weather chain\\u000a originating from the Sun. The first GIC observations were already made in early telegraph equipment about 150 years ago, and\\u000a since then several different

Risto Pirjola; Ari Viljanen; Antti Pulkkinen; Sami Kilpua; Olaf Amm

228

Mountain Weather  

NSDL National Science Digital Library

Mountains can be awe-inspiring both for the vistas they provide and for the weather events and long-term climate systems they support. This interactive feature illustrates how a moisture-laden air mass interacts with a mountain slope to produce characteristic patterns of precipitation over the mountain and surrounding areas. Viewers can see how clouds and precipitation form as the air mass ascends the windward side of the peak, and observe the rain shadow created on the leeward side by the descending, warmed, and moisture-depleted air. A background essay and list of discussion questions supplement the interactive feature.

229

Backyard Weather Stations  

NSDL National Science Digital Library

Learn how to build your own backyard weather station with complete directions provided by FamilyEducation.com's Web site, Backyard Weather Stations. The site shows exactly what you'll need and how to build the necessary components (e.g., rain gauge and barometer), as well as how to keep records of the data collected. Parents and teachers will enjoy watching the kids "learn the basics of scientific observation and record-keeping while satisfying their natural curiosity about weather."

Randall, Dennis.

230

Infrared Land Surface Remote Sensing using High Spectral Resolution Observations  

NASA Astrophysics Data System (ADS)

The authors will describe results of combining high spectral resolution infrared observations with high spatial resolution observations to provide an improved assessment of land surface characteristics. In particular, the high spectral resolution observations of the airborne Scanning-High-resolution Interferometer Sounder (S-HIS)and NPOESS Airborne Sounder Testbed - Interferometer (NAST-I) will be used to derive land surface temperature and infrared emissivity measurements. The MODIS Airborne Simulator (MAS) observations will be used to quantify the sub-pixel land surface variability. Ground truth observations from the Atmospheric Emitted Radiance Interferometer will be presented. The remote sensing techniques will be extended to the satellite based observations of the Interferometeric Monitor for greenhouse Gases (IMG) as well as to simulations of the AIRS and MODIS measurements from the NASA EOS Aqua platform.

Knuteson, R.; Deslover, D.; Larar, A.; Osborne, B.; Revercomb, H.; Short, J.; Smith, W.; Tanamachi, R.

231

Aeolian weathering of Venusian surface materials - Preliminary results from laboratory simulations  

NASA Technical Reports Server (NTRS)

An attempt is made to duplicate the atmospheric temperature, pressure, and approximate gas composition of all surface elevations on Venus by means of a simulator environment in which particles are impacted against rock targets as a way of studying planetary aeolian processes. While particles are abraded even at the low impact velocities envisioned for Venus, the same particles do not generate basaltic rock abrasion for impact velocities lower than 1 m/sec; comminution debris is instead transferred onto rock surfaces to form an accretion layer. These phenomena are seen as functions of the greater than 660 K temperatures encountered.

Marshall, John R.; Greeley, Ronald; Tucker, David W.; Pollack, James B.

1988-01-01

232

Observing Titan's Surface by Bistatic-Scattering: Cassini's Potential  

NASA Astrophysics Data System (ADS)

Bistatic-scattering is a well-established technique for determination of the nature and physical properties of planets and their satellites. Cassini offers an unprecedented opportunity to observe quasi-specular bistatic-scattering from an icy satellite, potentially at three coherent wavelengths. Circularly-polarized X-, S-, and Ka-band Radio Science signals transmitted from Cassini are observed at the NASA/DSN ground receiving stations after scattering from Titan's surface. Information regarding surface properties is recovered from analysis of the received echo intensity, polarization, and spectral properties. In particular, echo polarization over the Brewster-angle-range of icy surfaces (50-65 deg.) yields direct estimates of the (composite) surface dielectric constant independent of surface roughness (if surface scattering is dominant). Observations over a range of scattering angles yield additional diagnostic information regarding the nature of the scattering mechanism and related physical surface properties (liquid vs. solid, surface vs. volume, surface roughness, etc). The relatively low-altitude of many Titan flybys (950 km) yields excellent to good SNR within 15 minutes from closest-approach (C/A), even for surface reflectivity of only a few percent. In addition, the close flybys enhance potential echo detectability at all three wavelengths, yielding a wealth of information regarding dispersive characteristics of the scattering mechanism. More limited X-band-only observations may be achieved at fair SNR within roughly 40 minutes from C/A. The bistatic-scattering observations over a range of quasi-specular scattering angles provide excellent synergy to the backscattering-limited Earth-based-radar as well as Cassini RADAR observations. Support by the NASA/JPL Cassini Project is acknowledged.

Marouf, E.; French, R.; Rappaport, N.; Kliore, A.

2000-10-01

233

Sunspots, Space Weather and Climate  

NASA Technical Reports Server (NTRS)

Four hundred years ago this year the telescope was first used for astronomical observations. Within a year, Galileo in Italy and Harriot in England reported seeing spots on the surface of the Sun. Yet, it took over 230 years of observations before a Swiss amateur astronomer noticed that the sunspots increased and decreased in number over a period of about 11 years. Within 15 years of this discovery of the sunspot cycle astronomers made the first observations of a flare on the surface of the Sun. In the 150 years since that discovery we have learned much about sunspots, the sunspot cycle, and the Sun s explosive events - solar flares, prominence eruptions and coronal mass ejections that usually accompany the sunspots. These events produce what is called Space Weather. The conditions in space are dramatically affected by these events. Space Weather can damage our satellites, harm our astronauts, and affect our lives here on the surface of planet Earth. Long term changes in the sunspot cycle have been linked to changes in our climate as well. In this public lecture I will give an introduction to sunspots, the sunspot cycle, space weather, and the possible impact of solar variability on our climate.

Hathaway, David H.

2009-01-01

234

SPACE WEATHERING OF ROCK SURFACE WITHOUT REGOLITH: LABORATORY SIMULATION OF SPECTRAL CHANGE, S. Sasaki1  

E-print Network

Aerospace Exploration Agency (JAXA), Kanagawa 229-8510, Japan, 3 Department of Geological Science, Brown (having size of 550m) and performed a color imaging by onboard camera AMICA [13]. Almost 80% of Itokawa zones, dark boulder-rich surfaces usually superpose on bright materials. We can interpret that removal

Hiroi, Takahiro

235

Mid and late-Holocene vegetation, surface weathering and glaciation, Fjallsjökull, southeast Iceland  

Microsoft Academic Search

A natural section at the southern margin of Fjallsjökull in southeastern Iceland provides evidence of a mid-Holocene land-surface that has been deformed by 'Little Ice Age' glaciation. Deformation is inter preted as compression around coarse gravel core and extension along deformable silts. Restoration of the original sedimentary units reveals a succession of lake sediments and fan gravels, with pollen and

J. Rose; C. A. Whiteman; J. Lee; N. P. Branch; D. D. Harkness; J. Walden

1997-01-01

236

Electron- and Vacuum Ultraviolet Photon-Induced Weathering of Outer Solar System Surfaces  

NASA Astrophysics Data System (ADS)

This talk will present an overview of the non-thermal processes involved in the electron- and vacuum ultraviolet (VUV) photon-induced transformation of outer solar system surfaces. An emphasis will be made on i.) Understanding the initial electronic states created during electron impact and VUV photon absorption, ii.) The subsequent energy partitioning and release of excited fragments, iii.) The reactive scattering of atomic and molecular fragments and iv.) The trapping of products. Experiments are carried out using ultrahigh vacuum surface science techniques to achieve the very low vacuum and low temperatures typical of the outer solar system. The use of tunable excitation sources, quadrupole and time-of-flight mass spectrometry and Fourier transform infrared spectroscopy allows the determination of product branching ratios and absolute cross sections as a function of energy. The specific systems discussed will be pure and mixed (CO2:H2O) low-temperature ices, frozen sulfuric acid hydrates and flash-frozen sodium and magnesium sulfate brines. The mixed ices are simple models of comets and icy grain surfaces, whereas the latter are reasonable surrogates for the non-ice material(s) present on Europa. The talk should clearly indicate the important role electronic transitions play in chemically altering surfaces present in regions within the solar system that contain magnetospheres.

Orlando, T. M.

2002-12-01

237

Greenland surface albedo changes 1981-2012 from satellite observations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

238

Surface Water Temperature Observations of Large Lakes by Optimal Estimation  

E-print Network

Surface Water Temperature Observations of Large Lakes by Optimal Estimation Stuart N MacCallum(1 cloud screening have been developed to provide Lake Surface Water Temperature (LSWT) estimates from radiances. Therefore, the OE retrieval scheme developed is generic ­ i.e., applicable to all lakes. LSWTs

Merchant, Chris

239

Weathering of Martian Evaporites  

NASA Technical Reports Server (NTRS)

Evaporites in martian meteorites contain weathering or alteration features that may provide clues about the martian near-surface environment over time. Additional information is contained in the original extended abstract.

Wentworth, S. J.; Velbel, M. A.; Thomas-Keprta, K. L.; Longazo, T. G.; McKay, D. S.

2001-01-01

240

Thermal infrared spectroscopic observations of Mars from the Kuiper Airborne Observatory (KAO): Constraints on past climates and weathering products  

NASA Technical Reports Server (NTRS)

Spectral observations providing evidence for the presence of volatile-bearing minerals on the surface of Mars were obtained in 1988 and 1990 from the KAO. The 1988 data suggest the presence of 1-3 weight percent (wt%) of carbonate/bicarbonate and 10-15 wt% sulfate/bisulfate associated with martian atmospheric dust. Estimates of the optical depths are approximately 0.60 and approximately 0.35 in 1988 and 1990, respectively.

Roush, Ted L.; Pollack, James B.; Witteborn, Fred C.; Bregman, Jesse D.; Bell, James F., III; Sitton, Bradley

1995-01-01

241

The surface mass and energy balance of Nordenskiöldbreen, Svalbard: 7 years of in situ observations.  

NASA Astrophysics Data System (ADS)

In spring 2006 a climate monitoring program on Nordenskiöldbreen, Svalbard, was initiated, which is still on going. The program focuses on the dynamics and mass budget of the glacier, and includes mass balance (stake and sonic height ranger) and automatic weather station (AWS) observations. The annual mass balance observations show large variability and no trend over the observational period (2006-2013). The equilibrium line altitude (ELA) during this period is located at about 610 m a.s.l. This is in line with the average ELA over the period 1989-2010 of 631 m a.s.l. based on output of a distributed energy balance model (EBM), and slightly higher than presented in literature for this area. At the AWS site (±600 m a.s.l.) the average annual temperature is about -8.5°C. Annual mean wind speed is about 4.5 m/s and is predominantly directed down glacier with a directional constancy of about 0.65, a predominant katabatic wind. Throughout the year the sensible heat flux is positive due to a constant surface based temperature inversion. From May to September this temperature inversion is caused by cooling of the surface by long wave radiation while in the summer months the surface temperature is limited by 0°C, the temperature of a melting surface. At the AWS site the amount of melt energy available in the summer months corresponds to about 0.82 m w.e. snow and ice melt. This is less than derived from the observations (1.1 m w.e. of which 0.7 m w.e. is ice melt). This is due to problems with the temperature observations in the summer months resulting in an underestimation of the sensible heat flux towards the surface and consequently an underestimation of the melt flux.

Tijm-Reijmer, Carleen; Pohjola, Veijo; Van Pelt, Ward; Pettersson, Rickard

2014-05-01

242

Angular anisotropy of satellite observations of land surface temperature  

NASA Astrophysics Data System (ADS)

Satellite-based time series of land surface temperature (LST) have the potential to be an important tool to diagnose climate changes of the past several decades. Production of such a time series requires addressing several issues with using asynchronous satellite observations, including the diurnal cycle, clouds, and angular anisotropy. Here we evaluate the angular anisotropy of LST using one full year of simultaneous observations by two Geostationary Operational Environment Satellites, GOES-EAST and GOES-WEST, at the locations of five surface radiation (SURFRAD) stations. We develop a technique to convert directionally observed LST into direction-independent equivalent physical temperature of the land surface. The anisotropy model consists of an isotropic kernel, an emissivity kernel (LST dependence on viewing angle), and a solar kernel (effect of directional inhomogeneity of observed temperature). Application of this model reduces differences of LST observed from two satellites and between the satellites and surface ground truth - SURFRAD station observed LST. The techniques of angular adjustment and temporal interpolation of satellite observed LST open a path for blending together historical, current, and future observations of many geostationary and polar orbiters into a homogeneous multi-decadal data set for climate change research.

Vinnikov, Konstantin Y.; Yu, Yunyue; Goldberg, Mitchell D.; Tarpley, Dan; Romanov, Peter; Laszlo, Istvan; Chen, Ming

2012-12-01

243

Observation of water condensate on hydrophobic micro textured surfaces  

NASA Astrophysics Data System (ADS)

We visually observed that a dropwise condensation occurred initially and later changed into a filmwise condensation on hydrophobic textured surface at atmosphere pressure condition. It was observed that the condensate nucleated on the pillar side walls of the micro structure and the bottom wall adhered to the walls and would not be lifted to form a spherical water droplet using environmental scanning electron microscope.

Kim, Ki Wook; Do, Sang Cheol; Ko, Jong Soo; Jeong, Ji Hwan

2013-07-01

244

HST observations of Triton: Evidence of a changing surface  

Microsoft Academic Search

Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes (Soderblom et al. 1990). Prompted by evidence from previous observations at ground and space-based telescopes of possible seasonal surface changes on Triton (Herbert et al. 2004 and Young & Stern 1999), we proposed to confirm and characterize these changes using

J. M. Bauer; B. J. Buratti

2006-01-01

245

COSMO-SkyMed measurements in precipitation over the sea: analysis of Louisiana summer thunderstorms by simultaneous weather radar observations  

NASA Astrophysics Data System (ADS)

Radar signatures of rain cells are investigated using X-band synthetic aperture radar (X-SAR) images acquired from COSMO-SkyMed constellation over oceans off the coast of Louisiana in summer 2010 provided by ASI archive. COSMO-SkyMed (CSK) monitoring of Deepwater Horizon oil spill provided a big amount of data during the period April-September 2010 and in July-August when several thunderstorms occurred in that area. In X-SAR images, radar signatures of rain cells over the sea usually consist of irregularly shaped bright and dark patches. These signatures originate from 1) the scattering and attenuation of radiation by hydrometers in the rain cells and 2) the modification of the sea roughness induced by the impact of raindrops and by wind gusts associated with rain cell. However, the interpretation of precipitation signatures in X-SAR images is not completely straightforward, especially over sea. Coincident measurements from ground based radars and an electromagnetic (EM) model predicting radar returns from the sea surface corrugated by rainfall are used to support the analysis. A dataset consisting of 4 CSK images has been collected over Gulf of Mexico while a WSR-88D NEXRAD S-band Doppler radar (KLIX) located in New Orleans was scanning the nearby portion of ocean. Terrestrial measurements have been used to reconstruct the component of X-SAR returns due to precipitation by modifying the known technique applied on measurements over land (Fritz et al. 2010, Baldini et al. 2011). Results confirm that the attenuation signature in X-SAR images collected over land, particularly pronounced in the presence of heavy precipitation cells, can be related to the S-band radar reflectivity integrated along the same path. The Normalized Radar Cross Section (NRCS) of land is considered to vary usually up to a few dBs in case of rain but with strong dependency on the specific type and conditions of land cover. While the NRCS of sea surface in clear weather condition can be considered as constant, in case of rain, at X-SAR incidence angles, it exhibits a dependence to precipitation event due the combined effects of corrugation due to the impinging raindrops and to the surface wind. Therefore, when retrieving of X-SAR NRCS in precipitation over the sea, this effect must be accounted for and can be quantified based on the precipitation event using a simple NRCS surface model. In this work, an EM model based on Bahar's Full Wave Model is used for evaluating such NRCS depending on polarization, frequency and incidence angle for different values of wind velocity and the root mean square height of the corrugation induced by rainfall. The reconstruction of X-SAR returns in precipitation is finally obtained by joint utilization of volume reflectivity and attenuation estimated from KLIX and the sea NRCS model.

Roberto, N.; Baldini, L.; Gorgucci, E.; Facheris, L.; Chandrasekar, V.

2012-04-01

246

Mechanical Weathering  

NSDL National Science Digital Library

This activity was designed to give students an opportunity to realize that all rocks weather mechanically and each specific rock type has its own particular rate of weathering. Students discover that mechanical weathering is the process of breaking down bedrock into smaller fragments by physical as opposed to chemical means and that rock weathering, although it seems to occur slowly in human terms, is an extremely significant part of the rock cycle. They will learn that weathered rock materials are called sediments and are the structural basis for soils and can also be compacted into sedimentary rock. Students will realize that rock weathering rates vary widely depending on mineral content, texture, rock type, and climate and that differential weathering (varying weathering rates for two or more rock types in physical contact with each other) has given rise to some of the world's most breathtaking scenery.

247

Winter Weather  

MedlinePLUS

... About CDC.gov . Natural Disasters and Severe Weather Earthquakes Being Prepared Emergency Supplies Home Hazards Indoor Safety ... What's New A - Z Index Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis Volcanoes ...

248

Comparison between AVHRR surface temperature data and in-situ weather station temperatures over the Greenland Ice Sheet  

NASA Astrophysics Data System (ADS)

Advanced Very-High Resolution Radiometer (AVHRR) images have been exhaustively used to measure surface temperature time series of the Greenland Ice sheet. The purpose of this study is to assess the accuracy of monthly average ice sheet surface temperatures, derived from thermal infrared AVHRR satellite imagery on a 6.25 km grid. In-situ temperature data sets are from the Greenland Collection Network (GC-Net). GC-Net stations comprise sensors monitoring air temperature at 1 and 2 meter above the snow surface, gathered at every 60 seconds and monthly averaged to match the AVHRR temporal resolution. Our preliminary results confirm the good agreement between satellite and in-situ temperature measurements reported by previous studies. However, some large discrepancies still exist. While AVHRR provides ice surface temperature, in-situ stations measure air temperatures at different elevations above the snow surface. Since most in-situ data on ice sheets are collected by Automatic Weather Station (AWS) instruments, it is important to characterize the difference between surface and air temperatures. Therefore, we compared and analyzed average monthly AVHRR ice surface temperatures using data collected in 2002. Differences between these temperatures correlate with in-situ temperatures and GC-Net station elevations, with increasing differences at lower elevations and higher temperatures. The Summit Station (3199 m above sea level) and the Swiss Camp (1176 m above sea level) results were compared as high altitude and low altitude stations for 2002, respectively. Our results show that AVHRR derived temperatures were 0.5°K warmer than AWS temperature at the Summit Station, while this difference was 2.8°K in the opposite direction for the Swiss Camp with surface temperatures being lower than air temperatures. The positive bias of 0.5°K at the high altitude Summit Station (surface warmer than air) is within the retrieval error of AVHRR temperatures and might be in part due to atmospheric inversion. The large negative bias of 2.8°K at the low altitude Swiss Camp (surface colder than the air) could be caused by a combination of different factors including local effects such as more windy circumstances above the snow surface and biases introduced by the cloud-masking applied on the AVHRR images. Usually only satellite images acquired in clear-sky conditions are used for deriving monthly AVHRR average temperatures. Since cloud-free days are usually warmer, satellite derived temperatures tend to underestimate the real average temperatures, especially regions with frequent cloud cover, such as Swiss Camp. Therefore, cautions must be exercised while using ice surface temperatures derived from satellite imagery for glaciological applications. Eliminating the cloudy day's' temperature from the in-situ data prior to the comparison with AVHRR derived temperatures will provide a better assessment of AVHRR surface temperature measurement accuracy.

Rezvanbehbahani, S.; Csatho, B. M.; Comiso, J. C.; Babonis, G. S.

2011-12-01

249

Naturally weathered feldspar surfaces in the Navajo Sandstone aquifer, Black Mesa, Arizona: Electron microscopic characterization  

E-print Network

emission gun scanning electron microscope (FEG- SEM). Here, we report the first HRTEM observation of a 10: Electron microscopic characterization Chen Zhu a,*, David R. Veblen b , Alex E. Blum c , Stephen J. Chipera, was characterized with high-reso- lution transmission and analytical electron microscope (HRTEM-AEM) and field

Zhu, Chen

250

Weather Odds  

NSDL National Science Digital Library

The Weather Odds site helps users learn about the odds of various weather happening at monthly and daily levels. The site relies on past climate data from thousands of locations and it's a fine resource. In the Quick Weather Data area, visitors can check out popular United States locations or use the search engine to breeze along to their preferred habitat. This version of Weather Odds is compatible with all operating systems.

2014-05-08

251

Space Weathering in the Mercurian Environment  

NASA Technical Reports Server (NTRS)

Space weathering processes are known to be important on the Moon. These processes both create the lunar regolith and alter its optical properties. Like the Moon, Mercury has no atmosphere to protect it from the harsh space environment and therefore it is expected that it will also incur the effects of space weathering. However, there are many important differences between the environments of Mercury and the Moon. These environmental differences will almost certainly affect the weathering processes and the products of those processes. It should be possible to observe the effects of these differences in Vis (visible)/NIR (near infrared) spectra of the type expected to be returned by MESSENGER. More importantly, understanding these weathering processes and their consequences is essential for evaluating the spectral data returned from MESSENGER and other missions in order to determine the mineralogy and the Fe content of the Mercurian surface. Additional information is contained in the original extended abstract.

Noble, S. K.; Pieters, C. M.

2001-01-01

252

Real-Time Weather Data  

NSDL National Science Digital Library

This website provides real-time and forecast weather maps and data for the United States. The Satellite section contains satellite weather images from the GOES 8 and GOES 10 satellites, the Radar section contains radar weather images from NEXRAD radars, the Surface Data section contains plots of various weather conditions (temperatures, winds, pressure, precipitation), and the Upper Air section plots winds and temperatures across the United States.

253

Estimating long-term surface hydrological components by coupling remote sensing observation with surface flux model.  

SciTech Connect

A model framework for parameterized subgrid-scale surface fluxes (PASS) has been applied to use satellite data, models, and routine surface observations to infer root-zone available moisture content and evapotranspiration rate with moderate spatial resolution within Walnut River Watershed in Kansas. Biweekly composite normalized difference vegetative index (NDVI) data are derived from observations by National Oceanic and Atmospheric Administration (NOAA) satellites. Local surface observations provide data on downwelling solar irradiance, air temperature, relative humidity, and wind speed. Surface parameters including roughness length, albedo, surface water conductance, and the ratio of soil heat flux to net radiation are estimated; pixel-specific near-surface meteorological conditions such as air temperature, vapor pressure, and wind speed are adjusted according to local surface forcing. The PASS modeling system makes effective use of satellite data and can be run for large areas for which flux data do not exist and surface meteorological data are available from only a limited number of ground stations. The long-term surface hydrological budget is evaluated using radar-derived precipitation estimates, surface meteorological observations, and satellite data. The modeled hydrological components in the Walnut River Watershed compare well with stream gauge data and observed surface fluxes during 1999.

Song, J.; Wesely, M. L.

2002-05-02

254

Surface Turbulent Fluxes Over Pack Ice Inferred from TOVS Observations  

NASA Technical Reports Server (NTRS)

A one-dimensional, atmospheric boundary layer model is coupled to a thermodynamic ice model to estimate the surface turbulent fluxes over thick sea ice. The principal forcing parameters in this time-dependent model are the air temperature, humidity, and wind speed at a specified level (either at 2 m or at 850 mb) and the downwelling surface radiative fluxes. The free parameters. are the air temperature, humidity, and wind speed profiles below the specified level, the surface skin temperature, the ice temperature profile, and the surface turbulent fluxes. The goal is to determine how well we can estimate the turbulent surface heat and momentum fluxes using forcing parameters from atmospheric temperatures and radiative fluxes retrieved from the TIROS-N Operational Vertical Sounder (TOVS) data. Meteorological observations from the Lead Experiment (LeadEx, April 1992) ice camp are used to validate turbulent fluxes computed with the surface observations and the results are used to compare with estimates based on radio-sonde observations or with estimates based on TOVS data. We find that the TOVS-based estimates of the stress are significantly more accurate than those found with a constant geostrophic drag coefficient, with a root-mean-square error about half as large. This improvement is due to stratification effects included in the boundary layer model. The errors in the sensible heat flux estimates, however, are large compared to the small mean values observed during the field experiment.

Lindsay, R. W.; Francis, J. A.; Persson, P. O. G.; Rothrock, D. A.; Schweiger, A. J.

1996-01-01

255

Solar absorption over Europe from collocated surface and satellite observations  

NASA Astrophysics Data System (ADS)

Solar radiation is the primary source of energy for the Earth's climate system. Although the incoming and outgoing solar fluxes at the top of atmosphere can be quantified with high accuracy, large uncertainties still exist in the partitioning of solar absorption between surface and atmosphere. To compute best estimates of absorbed solar radiation at the surface and within the atmosphere representative for Europe during 2000-2010, we combine temporally homogeneous and spatially representative ground-based observations of surface downwelling solar radiation with collocated satellite-retrieved surface albedo and top-of-atmosphere net irradiance. We find best estimates of Europe land annual mean surface and atmospheric absorption of 117.3 ± 6 W m-2 (41.6 ± 2% of top-of-atmosphere incident irradiance) and 65.0 ± 3 W m-2 (23.0 ± 1%). The fractional atmospheric absorption of 23% represents a robust estimate largely unaffected by variations in latitude and season, thus, making it a potentially useful quantity for first-order validation of regional climate models. Uncertainties of the individual absorption estimates arise mostly from the measurements themselves. In this context, the surface albedo and the ground-based solar radiation data are the most critical variables. Other sources of uncertainty, like the multiplicative combination of spatially averaged surface solar radiation and surface albedo estimates, and the spatial representativeness of the point observations, are either negligibly small or can be corrected for.

Hakuba, M. Z.; Folini, D.; Schaepman-Strub, G.; Wild, M.

2014-03-01

256

A scheme for computing surface layer turbulent fluxes from mean flow surface observations  

NASA Technical Reports Server (NTRS)

A physical model and computational scheme are developed for generating turbulent surface stress, sensible heat flux and humidity flux from mean velocity, temperature and humidity at some fixed height in the atmospheric surface layer, where conditions at this reference level are presumed known from observations or the evolving state of a numerical atmospheric circulation model. The method is based on coupling the Monin-Obukov surface layer similarity profiles which include buoyant stability effects on mean velocity, temperature and humidity to a force-restore formulation for the evolution of surface soil temperature to yield the local values of shear stress, heat flux and surface temperature. A self-contained formulation is presented including parameterizations for solar and infrared radiant fluxes at the surface. Additional parameters needed to implement the scheme are the thermal heat capacity of the soil per unit surface area, surface aerodynamic roughness, latitude, solar declination, surface albedo, surface emissivity and atmospheric transmissivity to solar radiation.

Hoffert, M. I.; Storch, J.

1978-01-01

257

An estimation of snow accumulation on Svalbard glaciers on the basis of standard weather-station observations  

Microsoft Academic Search

Winter precipitation in the form of snow is the major factor determining accumulation on Arctic glaciers. In this paper, I present a simple method to assess snow accumulation on the glaciers of Svalbard. I deduce snow accumulation from the sum of winter precipitation and the fraction of precipitation of different types at a reference weather station. The accumulation is then

Mariusz Grabiec

2005-01-01

258

World Weather  

NSDL National Science Digital Library

What's going on in the world of weather? Are there storms around Sri Lanka? What about the snows of Kilimanjaro? These can be pressing questions, indeed, and the World Weather app is a great way to stay in touch with weather patterns around the globe. Users will find that they can just type in a city name to see the current weather and also zoom around the globe as they see fit. It's a remarkable addition to the world of existing weather tracking apps and is compatible with all operating systems.

Elias, Jaume S.

2014-02-20

259

Lunar surface roughness derived from LRO Diviner Radiometer observations  

NASA Astrophysics Data System (ADS)

Sunlit and shaded slopes have a variety of temperatures based on their orientation with respect to the Sun. Generally, greater slope angles lead to higher anisothermality within the field of view. This anisothermality is detected by measuring changing emitted radiance as a function of viewing angle or by measuring the difference in brightness temperatures with respect to observation wavelength. Thermal infrared measurements from the Lunar Reconnaissance Orbiter Diviner Radiometer were used to derive lunar surface roughness via two observation types: (1) nadir multispectral observations with full diurnal coverage and (2) multiple emission angle targeted observations. Measurements were compared to simulated radiance from a radiative equilibrium thermal model and Gaussian slope distribution model. Nadir observations most closely match a 20° RMS slope distribution, and multiple emission angle observations can be modeled using 20-35° RMS slope distributions. Limited sampling of the lunar surface did not show any clear variation in roughness among surface units. Two-dimensional modeling shows that surfaces separated by distances greater than 0.5-5 mm can remain thermally isolated in the lunar environment, indicating the length scale of the roughness features. Non-equilibrium conditions are prevalent at night and near sunrise and sunset, preventing the use of the equilibrium thermal model for roughness derivations using data acquired at these local times. Multiple emission angle observations also show a significant decrease in radiance at high emission angles in both daytime and nighttime observations, and hemispherical emissivity is lower than is apparent from nadir observations. These observations and models serve as a basis for comparison with similar measurements of other airless bodies and as an initial template for the interpretation of TIR measurements acquired under a variety of geometric conditions.

Bandfield, Joshua L.; Hayne, Paul O.; Williams, Jean-Pierre; Greenhagen, Benjamin T.; Paige, David A.

2015-03-01

260

Observation of a prewetting transition during surface melting of caprolactam  

NASA Astrophysics Data System (ADS)

The surface-induced melting of the closed-packed (100) face of the anisotropic molecular crystal caprolactam has been studied using x-ray reflectivity. A thin-to-thick film prewetting transition is observed at about 13 K below the bulk melting point. Only above this transition does the thickness of the quasiliquid layer increase continuously with temperature. We speculate that initially the surface melting proceeds via layering transitions.

Chandavarkar, Sumant; Geertman, Rob M.; de Jeu, Wim H.

1992-10-01

261

Emergent relation between surface vapor conductance and relative humidity profiles yields evaporation rates from weather data.  

PubMed

The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (C(surf)). C(surf) accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of C(surf) to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that land-atmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (arid-humid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and C(surf) can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle. PMID:23576717

Salvucci, Guido D; Gentine, Pierre

2013-04-16

262

Emergent relation between surface vapor conductance and relative humidity profiles yields evaporation rates from weather data  

PubMed Central

The ability to predict terrestrial evapotranspiration (E) is limited by the complexity of rate-limiting pathways as water moves through the soil, vegetation (roots, xylem, stomata), canopy air space, and the atmospheric boundary layer. The impossibility of specifying the numerous parameters required to model this process in full spatial detail has necessitated spatially upscaled models that depend on effective parameters such as the surface vapor conductance (Csurf). Csurf accounts for the biophysical and hydrological effects on diffusion through the soil and vegetation substrate. This approach, however, requires either site-specific calibration of Csurf to measured E, or further parameterization based on metrics such as leaf area, senescence state, stomatal conductance, soil texture, soil moisture, and water table depth. Here, we show that this key, rate-limiting, parameter can be estimated from an emergent relationship between the diurnal cycle of the relative humidity profile and E. The relation is that the vertical variance of the relative humidity profile is less than would occur for increased or decreased evaporation rates, suggesting that land–atmosphere feedback processes minimize this variance. It is found to hold over a wide range of climate conditions (arid–humid) and limiting factors (soil moisture, leaf area, energy). With this relation, estimates of E and Csurf can be obtained globally from widely available meteorological measurements, many of which have been archived since the early 1900s. In conjunction with precipitation and stream flow, long-term E estimates provide insights and empirical constraints on projected accelerations of the hydrologic cycle. PMID:23576717

Salvucci, Guido D.; Gentine, Pierre

2013-01-01

263

Technical Note: Surface water velocity observations from a camera: a case study on the Tiber River  

NASA Astrophysics Data System (ADS)

Monitoring surface water velocity during flood events is a challenging task. Techniques based on deploying instruments in the flow are often unfeasible due to high velocity and abundant sediment transport. A low-cost and versatile technology that provides continuous and automatic observations is still not available. LSPIV (large scale particle imaging velocimetry) is a promising approach to tackle these issues. Such technique consists of developing surface water velocity maps analyzing video frame sequences recorded with a camera. In this technical brief, we implement a novel LSPIV experimental apparatus to observe a flood event in the Tiber river at a cross-section located in the center of Rome, Italy. We illustrate results from three tests performed during the hydrograph flood peak and recession limb for different illumination and weather conditions. The obtained surface velocity maps are compared to the rating curve velocity and to benchmark velocity values. Experimental findings confirm the potential of the proposed LSPIV implementation in aiding research in natural flow monitoring.

Tauro, F.; Olivieri, G.; Petroselli, A.; Porfiri, M.; Grimaldi, S.

2014-10-01

264

Global chemical weather forecasts for field campaign planning: predictions and observations of large-scale features during MINOS, CONTRACE, and INDOEX  

NASA Astrophysics Data System (ADS)

The first global tropospheric forecasts of O3 and its precursors have been used in the daily flight planning of field measurement campaigns. The 3-D chemistry-transport model MATCH-MPIC is driven by meteorological data from a weather center (NCEP) to produce daily 3-day forecasts of the global distributions of O3 and related gases, as well as regional CO tracers. This paper describes the forecast system and its use in three field campaigns, MINOS, CONTRACE and INDOEX. An overview is given of the forecasts by MATCH-MPIC and by three other chemical weather forecast models (EURAD, ECHAM, and FLEXPART), focusing on O3 and CO. Total CO and regional CO tracers were found to be the most valuable gases for flight planning, due to their relatively well-defined anthropogenic source regions and lifetimes of one to a few months. CO was in good agreement with the observations on nearly all the flights (generally r > 0.7, and the relative RMS differences for the deviations from the means was less than 20%). In every case in which the chemical weather forecasts were primarily responsible for the flight plans, the targeted features were observed. Three forecasted phenomena are discussed in detail: outflow from Asia observed in the Mediterranean upper troposphere during MINOS, outflow from North America observed in the middle troposphere over northern Europe during CONTRACE, and the location of the "chemical ITCZ'' over the Indian Ocean during INDOEX. In particular it is shown that although intercontinental pollution plumes such as those observed during MINOS and CONTRACE occur repeatedly during the months around the campaigns, their frequency is sufficiently low (~10--30% of the time) that global chemical weather forecasts are important for enabling them to be observed during limited-duration field campaigns. The MATCH-MPIC chemical weather forecasts, including an interface for making customized figures from the output, are available for community use via http://www.mpch-mainz.mpg.de/~lawrence/forecasts.html.

Lawrence, M. G.; Rasch, P. J.; von Kuhlmann, R.; Williams, J.; Fischer, H.; de Reus, M.; Lelieveld, J.; Crutzen, P. J.; Schultz, M.; Stier, P.; Huntrieser, H.; Heland, J.; Stohl, A.; Forster, C.; Elbern, H.; Jakobs, H.; Dickerson, R. R.

2003-02-01

265

An attempt to comprehend Martian weathering conditions through the analysis of terrestrial palagonite samples  

NASA Technical Reports Server (NTRS)

Spectroscopic observations of the Martian surface in the invisible to near infrared (0.4-1.0 micron), coupled with measurements made by Viking, have shown that the surface is composed of a mixture of fine-grained weathered and nonweathered minerals. The majority of the weathered components are thought to be materials like smectite clays, scapolite, or palagonite. Until materials are returned for analysis there are two possible ways of proceeding with an investigation of Martian surface processes: (1) the study of weathering products in meteorites that have a Martian origin (SNC's), and (2) the analysis of certain terrestrial weathering products as analogs to the material found in SNC's, or predicted to be present on the Martian surface. We describe some preliminary measurements of the carbon chemistry of terrestrial palagonite samples that exhibit spectroscopic similarities with the Martian surface. The data should aid the understanding of weathering in SNC's and comparisons between terrestrial palagonites and the Martian surface.

Douglas, C.; Wright, I. P.; Bell, J. B.; Morris, R. V.; Golden, D. C.; Pillinger, C. T.

1993-01-01

266

Weathering in a Cup.  

ERIC Educational Resources Information Center

Two easy student activities that demonstrate physical weathering by expansion are described. The first demonstrates ice wedging and the second root wedging. A list of the needed materials, procedure, and observations are included. (KR)

Stadum, Carol J.

1991-01-01

267

Preliminary observations on the impact of complex stress histories on sandstone response to salt weathering: laboratory simulations of process combinations  

NASA Astrophysics Data System (ADS)

Historic sandstone structures carry an inheritance, or a ‘memory’, of past stresses that the stone has undergone since its placement in a façade. This inheritance, which conditions present day performance, may be made up of long-term exposure to a combination of low magnitude background environmental factors (for example, salt weathering, temperature and moisture cycling) and, superimposed upon these, less frequent but potentially high magnitude events or ‘exceptional’ factors (for example, lime rendering, severe frost events, fire). The impact of complex histories on the decay pathways of historic sandstone is not clearly understood, but this paper seeks to improve that understanding through the use of a laboratory ‘process combination’ study. Blocks of quartz sandstone (Peakmoor, from NW England) were divided into subsets that experienced different histories (lime rendering and removal, fire and freeze-thaw cycles in isolation and combination) that reflected the event timeline of a real medieval sandstone monument in NE Ireland, Bonamargy Friary (McCabe et al. 2006b). These subsets were then subject to salt weathering cycles using a 10% salt solution of NaCl and MgSO4 that represents the ‘every-day’ stress environment of, for example, sandstone structures in coastal, or polluted urban, location. Block response to salt weathering was monitored by collecting, drying and weighing the debris that was released as blocks were immersed in the salt solution at the beginning of each cycle. The results illustrate the complexity of the stone decay system, showing that seemingly small variations in stress history can produce divergent response to salt weathering cycles. Applied to real-world historic sandstone structures, this concept may help to explain the spatial and temporal variability of sandstone response to background environmental factors on a single façade, and encourage conservators to include the role of stress inheritance when selecting and implementing conservation strategies.

McCabe, S.; Smith, B. J.; Warke, P. A.

2007-03-01

268

Surface heat budget at the Nordic Seas in Lagrangian observations  

NASA Astrophysics Data System (ADS)

In the Nordic Seas, the warm, inflowing Atlantic Water is cooled until it is dense enough to sink. Thereafter it circulates at depth, eventually feeding the North Atlantic Deep Water. The air-sea interaction which facilitates this cooling is a complex process involving diverse phenomena, from surface heating to turbulent entrainment at the base of the ocean surface mixed layer. In the present study, we use 486 freely-drifting surface buoys to observe temperature changes on water parcels and the response to air-sea heat fluxes. Such Lagrangian observations advantageously 'filter out' horizontal heat fluxes, since the buoys are advected by the flow, allowing one to focus on the vertical exchanges. We examine the temporal evolution of temperature on the drifters and the correlations with surface heat fluxes, obtained from ECMWF ERA-Interim reanalyses. The frequency spectra indicate a clear ?-2 dependence at frequencies higher than roughly 1/40 days-1. The temperature fluctuations on the other hand are correlated with surface fluxes only at the longer time scales. We then show how the Lagrangian temperature can be represented as a stochastic process, with a deterministic portion determined by the low frequency atmospheric forcing and a white noise perturbation. This is in line with previous studies of the ocean surface response to stochastic wind forcing. What distinguishes the present model is the deterministic part, which must account for the gradual cooling of the water parcels.

de La Lama, Marta S.; Isachsen, Pål E.; Koszalka, Inga; Lacasce, Joseph H.

2014-05-01

269

Silicate weathering in anoxic marine sediments  

NASA Astrophysics Data System (ADS)

Two sediment cores retrieved at the northern slope of Sakhalin Island, Sea of Okhotsk, were analyzed for biogenic opal, organic carbon, carbonate, sulfur, major element concentrations, mineral contents, and dissolved substances including nutrients, sulfate, methane, major cations, humic substances, and total alkalinity. Down-core trends in mineral abundance suggest that plagioclase feldspars and other reactive silicate phases (olivine, pyroxene, volcanic ash) are transformed into smectite in the methanogenic sediment sections. The element ratios Na/Al, Mg/Al, and Ca/Al in the solid phase decrease with sediment depth indicating a loss of mobile cations with depth and producing a significant down-core increase in the chemical index of alteration. Pore waters separated from the sediment cores are highly enriched in dissolved magnesium, total alkalinity, humic substances, and boron. The high contents of dissolved organic carbon in the deeper methanogenic sediment sections (50-150 mg dm-3) may promote the dissolution of silicate phases through complexation of Al3+ and other structure-building cations. A non-steady state transport-reaction model was developed and applied to evaluate the down-core trends observed in the solid and dissolved phases. Dissolved Mg and total alkalinity were used to track the in-situ rates of marine silicate weathering since thermodynamic equilibrium calculations showed that these tracers are not affected by ion exchange processes with sediment surfaces. The modeling showed that silicate weathering is limited to the deeper methanogenic sediment section whereas reverse weathering was the dominant process in the overlying surface sediments. Depth-integrated rates of marine silicate weathering in methanogenic sediments derived from the model (81.4-99.2 mmol CO2 m-2 year-1) are lower than the marine weathering rates calculated from the solid phase data (198-245 mmol CO2 m-2 year-1) suggesting a decrease in marine weathering over time. The production of CO2 through reverse weathering in surface sediments (4.22-15.0 mmol CO2 m-2 year-1) is about one order of magnitude smaller than the weathering-induced CO2 consumption in the underlying sediments. The evaluation of pore water data from other continental margin sites shows that silicate weathering is a common process in methanogenic sediments. The global rate of CO2 consumption through marine silicate weathering estimated here as 5-20 Tmol CO2 year-1 is as high as the global rate of continental silicate weathering.

Wallmann, K.; Aloisi, G.; Haeckel, M.; Tishchenko, P.; Pavlova, G.; Greinert, J.; Kutterolf, S.; Eisenhauer, A.

2008-06-01

270

Marine surface temperature: Observed variations and data requirements  

Microsoft Academic Search

Measurements of temperature at the ocean surface are an indispensible part of the Global Climate Observing System (GCOS). We describe the varying coverage of these measurements from the mid-nineteenth century through to the present era of satellite data, along with ongoing attempts to augment the available digitized data base. We next survey attempts to remove systematic biases from both sea

D. E. Parker; C. K. Folland; M. Jackson

1995-01-01

271

SOLAR AND METEOROLOGICAL SURFACE OBSERVATION NETWORK (SAMSON) FOR NC, VA  

EPA Science Inventory

Solar and Meteorological Surface Observational Network (SAMSON) v1.0 data for 6 NWS stations in North Carolina and 4 in Virginia. Hourly solar elements are: extraterrestrial horizontal and extraterrestrial direct normal radiation; global, diffuse, and direct normal radiation. Met...

272

Hydrocarbon reactions over transition metals: observation of surface hydrogen  

SciTech Connect

One of the difficulties in establishing the mechanism and kinetic behavior of heterogeneous catalytic reactions has been that, typically, the experimental observables are the concentrations of reactants and products in the gas phase rather than those on the surface where the reaction actually occurs. A new technique is described which permits measurement of the thermodynamic activity of chemisorbed hydrogen under reaction conditions. The method utilizes a solid state electrochemical device to measure the thermodynamic activity of hydrogen at a gas-solid interface. The device is applied to study the sorption kinetics of pure hydrogen including hydrogen spillover and other nonidealities. The kinetics of the platinum catalyzed hydrogenations of ethylene, propylene, and acetylene were investigated over a wide range of temperatures (278-700/sup 0/K) at one atmosphere total pressure. The electrode measurements indicate that during reaction gaseous hydrogen is not in equilibrium with surface hydrogen. Multiple steady states are observed for the ethylene hydrogenation reaction over platinum. Unlike the platinum catalyzed reaction, ethylene hydrogenation over nickel exhibits gas-surface hydrogen equilibrium. The adsorption and dehydrogenation of propane, butane, and cyclohexane were also investigated. At temperatures where no reaction was observed in the gas phase, paraffins adsorb dissociatively. The energetics of the observed processes are discussed in terms of a surface intermediate stabilized by hyperconjugation of the adsorbed molecule.

Mullins, M.E.

1983-01-01

273

Land surface albedo based on GOES geostationary satellite observations  

NASA Astrophysics Data System (ADS)

Land surface albedo is the fraction of incoming solar radiation reflected by the land surface, and therefore can be a sensitive indicator of environmental changes. To this end, surface albedo is identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). NOAA's National Climatic Data Center (NCDC) recently adapted the Geostationary Surface Albedo (GSA; Lattanzio and Govaerts, 2010) algorithm for use with GOES data in support of a global albedo initiative led by the Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM). SCOPE-CM helps coordinate ECV production responding to GCOS, WMO, and CEOS goals. The GSA algorithm was developed jointly by EUMETSAT and Joint Research Centre (JRC) using a method proposed by Pinty et al. (2000) to determine surface albedo using day-time, cloud-free geostationary observations from a single visible band. For the GOES implementation, raw GOES observations are calibrated using International Satellite Cloud Climatology Project (ISCCP) coefficients. Surface angular anisotropy is determined through the inversion of the GSA radiative transfer model using multiple geostationary images collected over a day under different illumination conditions. The inversion process requires ancillary total column ozone and water vapor values, which are acquired from the 20th Century Reanalysis V2 data set. The GSA algorithm produces a 10-day composite surface albedo map. This product is initially being developed for the years 2000-2003. Product quality is being assessed through comparisons with MODIS products as well as ground-based measurements. NCDC is producing albedo products from both GOES-E (75°W) and GOES-W (135°W). These are being merged with like products from EUMETSAT based on METEOSAT (0° and 63°E) and from JMA based on the Geostationary Meteorological Satellite System (140°E). In the near future, NOAA's Climate Data Record Program will provide the albedo product over the entire GOES period of record (1978-present).

Matthews, J. L.; Lattanzio, A.; Hankins, B.; Knapp, K.; Privette, J. L.

2012-12-01

274

HST observations of Triton: Evidence of a changing surface.  

NASA Astrophysics Data System (ADS)

Triton is one of the few bodies in the solar system with observed cryo-volcanic activity, in the form of plumes (Soderblom et al. 1990). Prompted by evidence from previous observations at ground and space-based telescopes of possible seasonal surface changes on Triton (Herbert et al. 2004 and Young & Stern 1999), we proposed to confirm and characterize these changes using the HST ACS instrument to image Triton at UV,B,V,I and Methane-band wavelengths over as much of its surface as visible from near Earth. With Triton's angular diameter of nearly 0.13 arcsec in size, ACS's HRC mode afforded an approximately 5X5 pixel image of Triton's surface. With HST's resolution, four regions could be resolved at a time, and particular surface features were restricted to a certain quadrant of Triton's surface. Our request for 6 observing longitudes has allowed us to resolve the longitude of surface features to within 60 degrees. Preliminary analysis indicates a rotation light curve amplitude in excess of that predicted by static models (Hillier et al. 1994 & Hillier 1999). We will attempt to determine the resurfacing rates and set model constraints on activity and surface temperature as well as composition. Such constraints have profound implications for our understanding of Triton's evolution as well as the history of other outer solar system bodies, including outer solar system satellites that may undergo similar geophysical processes or have similar composition. Herbert, B.D., Buratti, B., Schmidt, B., & Bauer, J. 2003, AGU Fall Meeting Abstracts, 443. Hillier, J.K. 1999, Icarus, 139, 202. Hillier, J., Veverka, J., Helfenstein, P., & Lee, P. 1994, Icarus, 109, 296. Soderblom, L.A., Becker, T.L., Kieffer, S.W., Brown, R.H., Hansen, C.J., & Johnson, T.V. 1990, Science, 250, 410. Young, L.A., & Stern, A.S., AJ, 122, 449.

Bauer, J. M.; Buratti, B. J.

2006-05-01

275

Linking the Weather Generator with Regional Climate Model  

NASA Astrophysics Data System (ADS)

One of the downscaling approaches, which transform the raw outputs from the climate models (GCMs or RCMs) into data with more realistic structure, is based on linking the stochastic weather generator with the climate model output. The present contribution, in which the parametric daily surface weather generator (WG) M&Rfi is linked to the RCM output, follows two aims: (1) Validation of the new simulations of the present climate (1961-1990) made by the ALADIN-Climate Regional Climate Model at 25 km resolution. The WG parameters are derived from the RCM-simulated surface weather series and compared to those derived from weather series observed in 125 Czech meteorological stations. The set of WG parameters will include statistics of the surface temperature and precipitation series (including probability of wet day occurrence). (2) Presenting a methodology for linking the WG with RCM output. This methodology, which is based on merging information from observations and RCM, may be interpreted as a downscaling procedure, whose product is a gridded WG capable of producing realistic synthetic multivariate weather series for weather-ungauged locations. In this procedure, WG is calibrated with RCM-simulated multi-variate weather series in the first step, and the grid specific WG parameters are then de-biased by spatially interpolated correction factors based on comparison of WG parameters calibrated with gridded RCM weather series and spatially scarcer observations. The quality of the weather series produced by the resultant gridded WG will be assessed in terms of selected climatic characteristics (focusing on characteristics related to variability and extremes of surface temperature and precipitation). Acknowledgements: The present experiment is made within the frame of projects ALARO-Climate (project P209/11/2405 sponsored by the Czech Science Foundation), WG4VALUE (project LD12029 sponsored by the Ministry of Education, Youth and Sports of CR) and VALUE (COST ES 1102 action).

Dubrovsky, Martin; Farda, Ales; Skalak, Petr; Huth, Radan

2013-04-01

276

Rates of Chemical Weathering  

NSDL National Science Digital Library

In this activity, students will investigate the weathering of rocks by chemical processes. They will use effervescent cleansing tablets as a model for rock, and vary surface area, temperature, and acidity to see how rapidly the "rock" dissolves. This investigation will help them understand three of the factors that affect the rate of chemical weathering and develop better understanding of how to design controlled experiments by exploring only one experimental variable at a time.

Passow, Michael

277

Predicting Weather  

NSDL National Science Digital Library

By performing the activities presented in this website, fourth grade students can learn about weather instruments and data collection. This website, produced by the Government of Saskatchewan, also explores how the weather can impact local communities. Each activity presented here includes both objectives and assessment techniques for the lesson. Sixteen different activity suggestions provide students and teachers with ample opportunities to explore weather in the classroom.

2008-03-28

278

Weather Watch  

NSDL National Science Digital Library

The weather watch activity is designed to provide instruction on how to collect weather data from on-line databases. Following completion of this activity the user will be able to look up weather conditions for any city in North America, know what radar maps are used for and how to access them, and know how to access satellite images and make estimated guesses on cloud conditions for their area from them.

Hopson, R.

279

Weather Experiments  

NSDL National Science Digital Library

Looking for fun ways to learn about weather? Weather Wiz Kids has 39 fun weather related experiments for you to try. These experiments can be done in the classroom with your friends or even at home! Some of the experiments on the site include: tornado in a bottle, make lightning, make it rain, cloud in a bottle, what's in the wind, the Doppler Effect, and baking soda volcano.

2010-01-01

280

On comparison of modeled surface flux variations to aircraft observations.  

SciTech Connect

Evaluation of models of air-surface exchange is facilitated by an accurate match of areas simulated with those seen by micrometeorological flux measurements. Here, spatial variations in fluxes estimated with the parameterized subgrid-scale surface (PASS) flux model were compared to flux variations seen aboard aircraft above the Walnut River Watershed (WRW) in Kansas. Despite interference by atmospheric eddies, the areas where the modeled sensible and latent heat fluxes were most highly correlated with the aircraft flux estimates were upwind of the flight segments. To assess whether applying a footprint function to the surface values would improve the model evaluation, a two-dimensional correlation distribution was used to identify the locations and relative importance of contributing modeled surface pixels upwind of each segment of the flight path. The agreement between modeled surface fluxes and aircraft measurements was improved when upwind fluxes were weighted with an optimized footprint parameter {var_phi}, which can be estimated from wind profiler data and surface eddy covariance. Variations of the flight-observed flux were consistently greater than those modeled at the surface, perhaps because of the smoothing effect of using 1 km pixels in the model. In addition, limited flight legs prevented sufficient filtering of the effects of atmospheric convection, possibly accounting for some of the more prominent changes in fluxes measured along the flight paths.

Song, J.; Wesely, M. L.; Environmental Research; Northern Illinois Univ.

2003-07-30

281

Net surface heat flux over the North and South Atlantic in 1985-1986 from Day 1 predictions of the European Center for Medium Range Weather Forecast  

Microsoft Academic Search

Twelve months of data on surface heat fluxes (shortwave radiation, longwave radiation, latent heat and sensible heat, from August 1985 to July 1986), obtained from the European Center for Medium-Range Weather Forecast (ECMWF) on a grid of 1.125° latitude by 1.125° longitude were analyzed. Comparison with older data from ECMWF (Simonot and Le Treut, 1987) indicates the occurrence of significant

B. Barnier; J.-Y. Simonot

1990-01-01

282

Estimates of surface methane emissions over Europe using observed surface concentrations and the FLEXPART trajectory model  

NASA Astrophysics Data System (ADS)

We use surface methane observations from nine European ground stations, and the FLEXPART Lagrangian transport model to obtain surface methane emissions for 2010. Our inversion shows the strongest emissions from the Netherlands and the coal mines in Upper Silesia Poland. This is qualitatively consistent with the EDGAR surface flux inventory. We also report significant surface fluxes from wetlands in southern Finland during July and August and reduced wetland fluxes later in the year. Our simulated methane surface concentration captures at least half of the daily variability in the observations, suggesting that the transport model is correctly simulating the regional transport pathways over Europe. We also use our trajectory model to determine whether future space-based remote sensing instruments (MERLIN) will be able to detect both natural and anthropogenic changes in the surface flux strengths.

Weaver, C. J.; Kiemle, C.; Kawa, S. R.; Aalto, T.; Necki, J.; Steinbacher, M.; Arduini, J.; Apadula, F.; Berkhout, H.; Hatakka, J.; O'Doherty, S.

2013-12-01

283

Lunar Surface Habitat Configuration Assessment: Methodology and Observations  

NASA Technical Reports Server (NTRS)

The Lunar Habitat Configuration Assessment evaluated the major habitat approaches that were conceptually developed during the Lunar Architecture Team II Study. The objective of the configuration assessment was to identify desired features, operational considerations, and risks to derive habitat requirements. This assessment only considered operations pertaining to the lunar surface and did not consider all habitat conceptual designs developed. To examine multiple architectures, the Habitation Focus Element Team defined several adequate concepts which warranted the need for a method to assess the various configurations. The fundamental requirement designed into each concept included the functional and operational capability to support a crew of four on a six-month lunar surface mission; however, other conceptual aspects were diverse in comparison. The methodology utilized for this assessment consisted of defining figure of merits, providing relevant information, and establishing a scoring system. In summary, the assessment considered the geometric configuration of each concept to determine the complexity of unloading, handling, mobility, leveling, aligning, mating to other elements, and the accessibility to the lunar surface. In theory, the assessment was designed to derive habitat requirements, potential technology development needs and identify risks associated with living and working on the lunar surface. Although the results were more subjective opposed to objective, the assessment provided insightful observations for further assessments and trade studies of lunar surface habitats. This overall methodology and resulting observations will be describe in detail and illustrative examples will be discussed.

Carpenter, Amanda

2008-01-01

284

Experimental observation of quantum oscillation of surface chemical reactivities  

PubMed Central

Here we present direct observation of a quantum reactivity with respect to the amounts of O2 adsorbed and the rates of surface oxidation as a function of film thickness on ultrathin (2–6 nm) Pb mesas by scanning tunneling microscopy. Simultaneous spectroscopic measurements on the electronic structures reveal a quantum oscillation that originates from quantum well states of the mesas, as a generalization of the Fabry–Pérot modes of confined electron waves. We expect the quantum reactivity to be a general phenomenon for most ultrathin metal films with broad implications, such as nanostructure tuning of surface reactivities and rational design of heterogeneous catalysts. PMID:17517632

Ma, Xucun; Jiang, Peng; Qi, Yun; Jia, Jinfeng; Yang, Yu; Duan, Wenhui; Li, Wei-Xue; Bao, Xinhe; Zhang, S. B.; Xue, Qi-Kun

2007-01-01

285

The WegenerNet observing weather and climate at 1 km-scale resolution: a new look at convective precipitation and other local-scale processes  

NASA Astrophysics Data System (ADS)

The region Feldbach in Eastern Styria, Austria, characteristic for experiencing a rich variety of weather and climate patterns, has been selected by the WegCenter as a focus area for a pioneering weather and climate observation experiment at very high resolution: The WegenerNet climate station network region Feldbach (in brief WegenerNet) is comprised of 151 meteorological stations, which measure temperature, humidity, precipitation, and other parameters, with high accuracy in a tightly spaced grid (one station per ~2 km2; each with 5-min time sampling; ~1.4 km x 1.4 km grid in an ~20 km x 15 km area centered near the City of Feldbach at 46.93 °N, 15.90 °E). Since Jan 2007 the WegenerNet is providing, as part of the pilot and demonstration phase, regular measurements from the entire grid and since fall 2008 a complete quality-controlled data stream is available in near real time (data latency less than 1-2 hours) for visualization and download via the WegenerNet data portal (www.wegenernet.org). Currently (early 2009) the network demonstration is moving into its final phase, with consolidating maintenance procedures, advancing weather and climate data product development and completing the data portal bilingually (German, English). Full operations is foreseen to be reached mid 2009, from which on the net is scheduled as a long-term field experiment serving as a high-resolution monitoring and validation site for weather and climate research and applications. Adding further value, the WegenerNet data are complemented by lightening measurements in cooperation with the Inst. of Physics/Univ. of Munich (European LiNet network, including dedicated stations in Feldbach and Graz). In addition, a 3D-steerable Doppler weather radar (of the Styrian Hail Protection Society at Reicherhöhe near Graz) is available with un-obscured view of clouds and rain over the WegenerNet area, focusing its measurements on hail and heavy rainfall. Complementary hailpad measurements are planned as well (as of 2009). Many research projects investigating climate and environmental change and impacts, as well as local weather (extremes), will benefit from WegenerNet data covering the local scales from 1-10 km. This is a key domain for future high-resolution climate modeling and analysis, currently mainly covering the 10-50 km scale, for meeting the needs of climate impact models and studies in heterogeneous orography such as the Alpine region. Applications include validation of non-hydrostatic climate models operated at 1-10 km resolution for dynamical downscaling, validation of statistical climate downscaling techniques, in particular for precipitation, "ground-truth" provision for and validation of high-resolution atmospheric and hydrologic Earth observation data from satellites, validation of weather radar rain rate estimates, study of orography-local climate relationships, basin-scale and local water balance assessments, and many others. The presentation will introduce the WegenerNet and its characteristics and capabilities along the lines above and will show example applications of its (1 km x 1 km) weather and climate products, with focus on the highly-variable convective summer precipitation. On-line access will also be demonstrated (www.wegcenter.at/wegenernet, www.wegenernet.org).

Kirchengast, G.; Kabas, T.; Stieb, C.; Leuprecht, A.; Bichler, C.

2009-04-01

286

Wacky Weather  

ERIC Educational Resources Information Center

What do a leaf blower, water hose, fan, and ice cubes have in common? Ask the students who participated in an integrative science, technology, engineering, and mathematics (I-STEM) education unit, "Wacky Weather," and they will tell say "fun and severe weather"--words one might not have expected! The purpose of the unit…

Sabarre, Amy; Gulino, Jacqueline

2013-01-01

287

Observations of water vapor ions at the lunar surface.  

NASA Technical Reports Server (NTRS)

The Apollo 14 Suprathermal Ion Detector Experiment observed a series of bursts of 48.6 eV water vapor ions at the lunar surface during a 14-hr period on Mar. 7, 1971. The maximum flux observed was 100 million ions per sq cm per sec per sr. These ions were also observed at Apollo 12, 183 km to the west. Evaluation of specific artificial sources including the Apollo missions and the Russian Lunokhod leads to the conclusion that the water vapor did not come from a man-made source. Natural sources exogenous to the moon such as comets and the solar wind are also found to be inadequate to explain the observed fluxes. Consequently, these water vapor ions appear to be of lunar origin.-

Freeman, J. W., Jr.; Hills, H. K.; Lindeman, R. A.; Vondrak, R. R.

1973-01-01

288

High-frequency radar observations of ocean surface currents.  

PubMed

This article reviews the discovery, development, and use of high-frequency (HF) radio wave backscatter in oceanography. HF radars, as the instruments are commonly called, remotely measure ocean surface currents by exploiting a Bragg resonant backscatter phenomenon. Electromagnetic waves in the HF band (3-30 MHz) have wavelengths that are commensurate with wind-driven gravity waves on the ocean surface; the ocean waves whose wavelengths are exactly half as long as those of the broadcast radio waves are responsible for the resonant backscatter. Networks of HF radar systems are capable of mapping surface currents hourly out to ranges approaching 200 km with a horizontal resolution of a few kilometers. Such information has many uses, including search and rescue support and oil-spill mitigation in real time and larval population connectivity assessment when viewed over many years. Today, HF radar networks form the backbone of many ocean observing systems, and the data are assimilated into ocean circulation models. PMID:22809196

Paduan, Jeffrey D; Washburn, Libe

2013-01-01

289

Surface moisture and satellite microwave observations in semiarid southern Africa  

SciTech Connect

Nimbus 7 scanning multichannel microwave radiometer 6.6-GHz passive microwave data were studied in relation to large-scale soil moisture estimates over a 3-year period in southeastern Bostwana. An extensive data base of weekly surface soil moisture measurements was used with meteorological data to estimate pixel average soil moisture on a daily basis. The influence of the vegetation canopy on the surface emissivity was studied by partitioning the data set into classes on the basis of the normalized difference vegetation index. After correcting for the vegetation optical depth, a correlation of r = 0.84 was established between the normalized brightness temperature observations and surface soil moisture for the 3-year period.

Owe, M.; Chang, A.T.C. (NASA Goddard Space Flight Center, Greenbelt, MD (United States)); Van de Griend, A.A. (Free Univ., Amsterdam (Netherlands))

1992-03-01

290

Locating Potential Biosignatures on Europa from Surface Geology Observations  

NASA Astrophysics Data System (ADS)

We evaluated the astrobiological potential of the major classes of geologic units on Europa with respect to possible biosignatures preservation on the basis of surface geology observations. These observations are independent of any formational model and therefore provide an objective, though preliminary, evaluation. The assessment criteria include high mobility of material, surface concentration of non-ice components, relative youth, textural roughness, and environmental stability. Our review determined that, as feature classes, low-albedo smooth plains, smooth bands, and chaos hold the highest potential, primarily because of their relative young age, the emplacement of low-viscosity material, and indications of material exchange with the subsurface. Some lineaments and impact craters may be promising sites for closer study despite the comparatively lower astrobiological potential of their classes. This assessment will be expanded by multidisciplinary examination of the potential for habitability of specific features.

Figueredo, Patricio H.; Greeley, Ronald; Neuer, Susanne; Irwin, Louis; Schulze-Makuch, Dirk

2003-12-01

291

ATLAS-3 correlative measurement opportunities with UARS and surface observations  

NASA Technical Reports Server (NTRS)

The third ATmospheric Laboratory for Applications and Science (ATLAS-3) mission was flown aboard the Space Shuttle launched on November 3, 1994. The mission length was approximately 10 days and 22 hours. The ATLAS-3 Earth-viewing instruments provided a large number of measurements which were nearly coincident with observations from experiments on the Upper Atmosphere Research Satellite (UARS). Based on ATLAS-3 instrument operating schedules, simulations were performed to determine when and where correlative measurements occurred between ATLAS and UARS instruments, and between ATLAS and surface observations. Results of these orbital and instrument simulations provide valuable information for scientists to compare measurements between various instruments on the two satellites and at selected surface sites.

Harrison, Edwin F.; Denn, Fred M.; Gibson, Gary G.

1995-01-01

292

Locating potential biosignatures on Europa from surface geology observations.  

PubMed

We evaluated the astrobiological potential of the major classes of geologic units on Europa with respect to possible biosignatures preservation on the basis of surface geology observations. These observations are independent of any formational model and therefore provide an objective, though preliminary, evaluation. The assessment criteria include high mobility of material, surface concentration of non-ice components, relative youth, textural roughness, and environmental stability. Our review determined that, as feature classes, low-albedo smooth plains, smooth bands, and chaos hold the highest potential, primarily because of their relative young age, the emplacement of low-viscosity material, and indications of material exchange with the subsurface. Some lineaments and impact craters may be promising sites for closer study despite the comparatively lower astrobiological potential of their classes. This assessment will be expanded by multidisciplinary examination of the potential for habitability of specific features. PMID:14987486

Figueredo, Patricio H; Greeley, Ronald; Neuer, Susanne; Irwin, Louis; Schulze-Makuch, Dirk

2003-01-01

293

Near surface magnetic domain observation with ultra-high resolution  

NASA Astrophysics Data System (ADS)

Near field magnetic force microscopy (NF-MFM) has been demonstrated to locally observe the magnetic fine structures in nanosized recording bits at an operating distance of 1 nm. The nanoscale magnetic domains, the polarity of surface magnetic charges, as well as the 3D magnetic fields leaking from the bits are investigated via NF-MFM with a soft NiFe tip. A Fourier analysis of the images suggests that the magnetic moment can be determined locally in a volume as small as 5 nanometers. The NF-MFM is crucial to the analysis of surface magnetic features and allows a wide range of future applications, for example, in data storage and biomedicine.Near field magnetic force microscopy (NF-MFM) has been demonstrated to locally observe the magnetic fine structures in nanosized recording bits at an operating distance of 1 nm. The nanoscale magnetic domains, the polarity of surface magnetic charges, as well as the 3D magnetic fields leaking from the bits are investigated via NF-MFM with a soft NiFe tip. A Fourier analysis of the images suggests that the magnetic moment can be determined locally in a volume as small as 5 nanometers. The NF-MFM is crucial to the analysis of surface magnetic features and allows a wide range of future applications, for example, in data storage and biomedicine. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr02215g

Li, Zhenghua; Li, Xiang; Liu, Dongping; Saito, H.; Ishio, S.

2014-09-01

294

TIMS observations of surface emissivity in HAPEX-Sahel  

NASA Technical Reports Server (NTRS)

The Thermal Infrared Multispectral Scanner (TIMS) was flown on the NASA C-130 aircraft for a series of 12 flights during HAPEX-Sahel at altitudes ranging from 0.25 to 6 km (0.6 to 15 m resolution). TIMS provides coverage of the 8 to 12 micrometer thermal infrared band in 6 contiguous channels. Thus it is possible to observe the spectral behavior of the surface emissivity over this wavelength interval.

Schmugge, Thomas; Hook, Simon; Kahle, Anne

1995-01-01

295

Observation of surface dark solitons in nonlocal nonlinear media.  

PubMed

We investigated surface dark solitons (SDSs) at the interface between a self-defocusing nonlocal nonlinear medium and a linear medium, both theoretically and experimentally. We demonstrate that fundamental and higher-order SDSs can exist when the linear refractive index of the self-defocusing medium is much greater than that of the linear medium. The fundamental and second-order solitons are observed at the interface between air and a weakly absorbing liquid. PMID:24978730

Gao, XingHui; Wang, Jing; Zhou, Luohong; Yang, ZhenJun; Ma, Xuekai; Lu, Daquan; Guo, Qi; Hu, Wei

2014-07-01

296

Hyperspectral Observations of Land Surfaces Using Ground-based, Airborne, and Satellite Sensors  

NASA Astrophysics Data System (ADS)

The University of Wisconsin-Madison Space Science and Engineering Center (UW-SSEC) has helped pioneer the use of high spectral resolution infrared spectrometers for application to atmospheric and surface remote sensing. This paper is focused on observations of land surface infrared emission from high spectral resolution measurements collected over the past 15 years using airborne, ground-based, and satellite platforms. The earliest data was collected by the High-resolution Interferometer Sounder (HIS), an instrument designed in the 1980s for operation on the NASA ER-2 high altitude aircraft. The HIS was replaced in the late 1990s by the Scanning-HIS instrument which has flown on the NASA ER-2, WB-57, DC-8, and Scaled Composites Proteus aircraft and continues to support field campaigns, such as those for EOS Terra, Aqua, and Aura validation. Since 1995 the UW-SSEC has fielded a ground-based Atmospheric Emitted Radiance Interferometer (AERI) in a research vehicle (the AERIBAGO) which has allowed for direct field measurements of land surface emission from a height of about 16 ft above the ground. Several ground-based and aircraft campaigns were conducted to survey the region surrounding the ARM Southern Great Plains site in north central Oklahoma. The ground- based AERIBAGO has also participated in surface emissivity campaigns in the Western U.S.. Since 2002, the NASA Atmospheric InfraRed Sounder (AIRS) has provided similar measurements from the Aqua platform in an afternoon sun-synchronous polar orbit. Ground-based and airborne observations are being used to validate the land surface products derived from the AIRS observations. These cal/val activities are in preparation for similar measurements anticipated from the operational Cross-track InfraRed Sounder (CrIS) on the NPOESS Preparatory Platform (NPP), expected to be launched in 2008. Moreover, high spectral infrared observations will soon be made by the Infrared Atmospheric Sounder Interferometer (IASI) on the European MetOp platform as well as a planned series of Chinese polar orbiting satellites. The detailed understanding of the land surface infrared emission is a crucial step in the effective utilization of these advanced sounder instruments for the extraction of atmospheric composition information (esp. water vapor vertical profile) over land, which is a key goal for numerical weather prediction data assimilation.

Knuteson, R. O.; Best, F. A.; Revercomb, H. E.; Tobin, D. C.

2006-12-01

297

Observation of dynamic water microadsorption on Au surface  

SciTech Connect

Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12??m{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

Huang, Xiaokang, E-mail: xiaokang.huang@tqs.com; Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold [TriQuint Semiconductor, Inc., 500 W Renner Road, Richardson, Texas 75080 (United States)

2014-05-15

298

TES Observations of Chryse and Acidalia Planitiae: Multiple Working Hypotheses for Distributions of Surface Compositions  

NASA Technical Reports Server (NTRS)

A gradation of surface units represents either (1) an influx of basaltic sediment from southern highlands, deposited on andesitic volcanics, or (2) incompletely weathered basalt marking the geographic extent of submarine alteration of basaltic crust. Additional information is contained in the original extended abstract.

Wyatt, M. B.; Bandfield, J. L.; McSween, H. Y., Jr.; Christensen, P. R.; Moersch, J.

2002-01-01

299

Cassini First Radio Science Observations of Titan's Atmosphere and Surface  

NASA Astrophysics Data System (ADS)

The first two Cassini radio occultations of Titan's atmosphere occurred on March 18 (T12) and May 20 (T14), 2006. The atmosphere was probed on the ingress and egress sides, yielding observations at four mid-southern latitudes. Titan's surface was also probed using bistatic-scattering during the inbound period on T12 and the inbound and outbound periods on T14. In all cases, quasi-monochromatic S-, X-, and Ka-bands RCP signals (13, 3.6, and 0.94 cm-wavelength, respectively) were transmitted from Cassini. Both the RCP and LCP signal components were observed at multiple ground receiving stations of the NASA/DSN. Demanding spacecraft maneuvers to point the Cassini high-gain antenna to virtual Earth during the occultations, and to track the specular region on Titan's surface during the bistatic observations were successfully implemented. For the first time ever, quasi-specular bistatic scattering surface echo is detected on both the inbound and outbound T14 observations. Although weak, an X-band RCP and LCP reflected spectral components are clearly detectable. Their total power ratio determines the refractive index of the regions probed and its likely nature (liquid vs solid). The echo appears consistent with reflection from localized hydrocarbon liquid regions embedded in mostly nonspecularly reflecting terrain. The atmospheric refracted S and X signals were tracked down to Titan's surface. The Ka signal was consistently extinguished by atmospheric absorption at about 10 km above the surface. Observed changes of signal frequency is used to recover the refractivity profiles of the neutral atmosphere, hence determine the corresponding temperature-pressure profiles assuming 100% N2 composition. Changes of signal strength, corrected to remove refractive defocusing, reveals both small-scale and large-scale effects. The former is likely due to gravity waves, turbulence, and layers. The latter exhibits remarkable wavelength dependence and is likely caused by dispersive N2-N2 collision-induced gaseous absorption, although additional extinction mechanisms may also be responsible.

Marouf, Essam A.; Flasar, F. M.; French, R. G.; Kliore, A. J.; Nagy, A. F.; Rappaport, N. J.; Schinder, P. J.; McGhee, C. A.; Simpson, R.; Anabtawi, A.; Asmar, S.; Barbinis, E.; Goltz, G.; Fleischman, D.; Kahan, D.; Rochblatt, D.

2006-09-01

300

Satellite Based Mapping of Land Surface ET using MODIS and Alternate Surface Meteorological Inputs from AMSR-E, Reanalysis, and Surface Weather Stations  

Microsoft Academic Search

Regional evapotranspiration (ET), including water loss from plant transpiration and soil evaporation, is essential to understanding interactions between land-atmosphere surface energy and water balances. Vapor pressure deficit (VPD) and surface air temperature are key variables for stomatal conductance and ET estimation. We developed an algorithm to estimate ET using a modified Penman-Monteith approach driven by MODIS derived vegetation data and

Q. Mu; L. A. Jones; J. S. Kimball; S. W. Running

2007-01-01

301

Pre-Observational Evolution of Surface Temperature in Romania as Inferred from Borehole Temperature Measurements  

NASA Astrophysics Data System (ADS)

Temperature data from nine boreholes in the Carpathian orogen in Romania were used to obtain information on the ground surface temperature history (GSTH) in the last 250 years. The temperature measurements were taken with a thermistor probe (sensitivity in the 10 mK range) using the stop-and-go technique, at 10 m intervals, in the depth range of 20-580 m. The least squares inverse modelling approach of Tarantola and Valette (J Geophys 50:159-170, 1982) was used to infer the GSTH. Long-term air temperature records available from the Romanian weather station network were used as a comparison term for the first 100-150 years of the GSTH, and as a forcing function in a POM-SAT model that combines borehole temperature profiles (BTPs) and meteorological time series (surface air temperature, SAT) to produce information on the so-called pre-observational mean (POM). Results from a global circulation model for the Romanian area are incorporated in the discussion as well.

Demetrescu, Crisan; Tumanian, Maria; Dobrica, Venera; Mares, Constantin; Mares, Ileana

2012-01-01

302

Thermophysical Properties of the Lunar Surface from Diviner Observations  

NASA Astrophysics Data System (ADS)

Orbital thermal infrared measurements are sensitive to a variety of properties of the Moon's surface layer, including rock abundance, regolith cover and porosity, and small-scale surface roughness. With its multiple spectral channels and large dynamic temperature range, the Diviner Lunar Radiometer [1] on NASA's LRO spacecraft has enabled the first global, high-resolution maps of these important thermophysical properties. Here we present a summary of the results of Diviner's thermophysical investigation thus far. Maps of surface rock abundance show low typical values of <1% with higher abundances for recent craters and their blocky ejecta, as well as mass wasting on crater walls, rilles, and impact melt features [2]. The extent and abundance of surface rocks decrease systematically with crater age, and rocky surfaces are only preserved on the youngest craters (<1 Ga). We used nighttime regolith surface temperatures and eclipse cooling observations to constrain profiles of density and conductivity in the upper ~1 m, revealing a remarkably homogeneous subsurface structure [3]. Geographic variations in upper regolith density are nonetheless apparent. For example, buried rocks are suggested within young impact ejecta showing strong radar backscatter, high subsurface density, and a lack of surface rocks [2,4]. Rock fragmentation and regolith accumulation rates can be quantified by comparison of the Diviner data with published crater ages, yielding typical erosion rates which rapidly decrease from ~10 kg m-2 yr-1 for crater ages of ~1 Ma to ~1 mg m-2 yr-1 at ~1 Ga [4]. Variations in upper regolith density correlate with the ages of individual mare basalt units, suggesting this layer is actively processed by impacts on geologically short timescales, which may reveal age relationships previously unseen [5]. Vast cold regions surrounding fresh impact craters during lunar night (termed "cold spots") are only apparent in thermal infrared data [2]. These features cannot be explained by the emplacement of ejecta, and instead are well modeled by the in situ decompression of the top ~1-10 cm of regolith. Among a variety of explanations for this phenomenon, a model of grain lifting and turbulent mixing within an expanding vapor cloud best matches observations. The Diviner observations suggest impact vaporization leads to prominent yet ephemeral scars in the upper regolith that may be common on airless bodies in the Solar System. Surface roughness at scales smaller than the ~250 m Diviner footprint affects the measured spectral slope in brightness temperatures. We used Diviner brightness temperature spectra measured at a variety of solar illumination and viewing geometries to constrain and map the RMS slopes of the Moon's surface [6]. Due to the general increase in roughness at smaller scales, the RMS slopes of ~20-30° derived from Diviner data are likely dominated by the smallest scales where strong temperature gradients can exist, which are of order millimeters for typical lunar regolith [7,8]. Thus, these measurements complement those acquired by other techniques, such as laser altimetry [9], which typically measure surface roughness at scales larger than one meter. [1] Paige D. A., et al. (2009) Space Sci. Rev., 150, 135-160. [2] Bandfield J. L., et al. (2011) J. Geophys. Res., 116, E00H02. [3] Vasavada A. R., et al. (2012), J. Geophys. Res., 117, E00H18. [4] Ghent R., et al. (2012) AGU Fall Mtg., #P42A-07. [5] Hayne P. O., et al. (2013) Lunar and Planet. Sci. Conf. XLIV. [6] Hayne P. O., et al. (2013) Lunar and Planet. Sci. Conf. XLIII, #2829. [7] Buhl D., et al. (1968) J. Geophys. Res., 73, 5281-5295. [8] Williams J-P., et al. (2012) EPSC-DPS2011, vol. 6, 1678. [9] Rosenburg M. A., et al (2011), J. Geophys. Res., 116, E02001.

Hayne, Paul; Bandfield, Joshua; Vasavada, Ashwin; Ghent, Rebecca; Siegler, Matthew; Williams, Jean-Pierre; Greenhagen, Benjamin; Aharonson, Oded; Paige, David

2013-04-01

303

Material properties for mantle convection consistent with observed surface fields  

NASA Technical Reports Server (NTRS)

An attempt is made to derive constraints on mantle convection from observed surface fields: plate velocities, gravity, topography and heat flow. The spherical harmonic spectra of the fields are expressed in terms of a spectral magnitude and slope, and requirements for the minimal representation of the equations for mantle convection are discussed. The effects of the boundary layer represented by the surface fields on convection at the mantle surface and at deeper levels are then examined, and a mean value of the effective mantle viscosity of approximately 10 to the 23rd g/cm per sec is obtained, together with values of 10 to the 8th and 10 to the 7th for the Rayleigh numbers of whole mantle and upper mantle convection, respectively. Consideration is then given to the compositional, thermal and rheological aspects of mantle convection, and it is pointed out that constraints on the depth and other properties of convection will require more detailed modeling using the relationships between the harmonic coefficients of the surface fields.

Kaula, W. M.

1980-01-01

304

Land surface thermal environment during heat wave event measured by satellite observation  

NASA Astrophysics Data System (ADS)

In summer 2013, mainly from July to August, most parts of China continued to experience an unusually severe heat wave with exceptionally high air temperatures, based on the records measured at meteorological stations. As a supplement to the weather station networks, remotely sensed observation can quantify detailed variation of surface temperature at relatively high spatial resolution, owing to its ability to provide a complete and homogeneous data sources. In addition to the GHCN CAMS gridded land air surface temperature, land surface temperature products of MODIS including MOD11C3/MYD11C3 and MOD11A2/MYD11A2 were used to evaluate the anomaly of summertime thermal environment over the South China in 2013. To investigate the impacts of heat wave event on built environment, the MODIS Land Cover Type yearly product (MCD12Q1) was collected. Regional thermal anomaly was observed in both air and surface temperature measurements, especially for August. Statistics based on MOD11A2/MYD11A2 shows the spatio-temporal variation of land surface temperature at regional scale, and the heterogeneous characteristics in diurnal cycle are also shown. Compared with other types, the urban and built-up generally presents larger surface temperature at daytime. Detailed analyses were further conducted for three selected regions roughly covering the Yangtze River Delta, the Pearl River Delta, and the areas around Wuhan City respectively. Findings indicate that urban and built-up exhibits more distinct thermal contrast to its surroundings at daytime, in contrast to the situation at nighttime. This thermal contrast was defined as surface urban heat island intensity (UHII) calculated using a newly proposed procedure, in this paper. The UHII shows both time- and geography-dependent variations. Meanwhile, the UHII over medium and small cities was even more obvious and larger than that over megalopolitan areas. These preliminary findings suggest that land use and land cover changes as a consequence of rapid urbanization possibly gives positive feedback to warming anomaly during heat wave event. The exacerbated warming of built-up environment, not only over megalopolitan areas but also over medium and small cities, deserves our attention in urban management.

Chen, Feng; Yang, Song

2014-11-01

305

Near surface magnetic domain observation with ultra-high resolution.  

PubMed

Near field magnetic force microscopy (NF-MFM) has been demonstrated to locally observe the magnetic fine structures in nanosized recording bits at an operating distance of 1 nm. The nanoscale magnetic domains, the polarity of surface magnetic charges, as well as the 3D magnetic fields leaking from the bits are investigated via NF-MFM with a soft NiFe tip. A Fourier analysis of the images suggests that the magnetic moment can be determined locally in a volume as small as 5 nanometers. The NF-MFM is crucial to the analysis of surface magnetic features and allows a wide range of future applications, for example, in data storage and biomedicine. PMID:25118950

Li, Zhenghua; Li, Xiang; Liu, Dongping; Saito, H; Ishio, S

2014-10-01

306

Weatherizing America  

ScienceCinema

As Recovery Act money arrives to expand home weatherization programs across the country, Zachary Stewart of Phoenix, Ariz., and others have found an exciting opportunity not only to start working again, but also to find a calling.

Stewart, Zachary; Bergeron, T.J.; Barth, Dale; Qualis, Xavier; Sewall, Travis; Fransen, Richard; Gill, Tony;

2013-05-29

307

Weatherizing America  

SciTech Connect

As Recovery Act money arrives to expand home weatherization programs across the country, Zachary Stewart of Phoenix, Ariz., and others have found an exciting opportunity not only to start working again, but also to find a calling.

Stewart, Zachary; Bergeron, T.J.; Barth, Dale; Qualis, Xavier; Sewall, Travis; Fransen, Richard; Gill, Tony

2009-01-01

308

Coupled atmosphere and land-surface assimilation of surface observations with a single column model and ensemble data assimilation  

NASA Astrophysics Data System (ADS)

Numerical weather prediction and data assimilation models are composed of coupled atmosphere and land-surface (LS) components. If possible, the assimilation procedure should be coupled so that observed information in one module is used to correct fields in the coupled module. There have been some attempts in this direction using optimal interpolation, nudging and 2/3DVAR data assimilation techniques. Aside from satellite remote sensed observations, reference height in-situ observations of temperature and moisture have been used in these studies. Among other problems, difficulties in coupled atmosphere and LS assimilation arise as a result of the different time scales characteristic of each component and the unsteady correlation between these components under varying flow conditions. Ensemble data-assimilation techniques rely on flow dependent observations-model covariances. Provided that correlations and covariances between land and atmosphere can be adequately simulated and sampled, ensemble data assimilation should enable appropriate assimilation of observations simultaneously into the atmospheric and LS states. Our aim is to explore assimilation of reference height in-situ temperature and moisture observations into the coupled atmosphere-LS modules(simultaneously) in NCAR's WRF-ARW model using the NCAR's DART ensemble data-assimilation system. Observing system simulation experiments (OSSEs) are performed using the single column model (SCM) version of WRF. Numerical experiments during a warm season are centered on an atmospheric and soil column in the South Great Plains. Synthetic observations are derived from "truth" WRF-SCM runs for a given date,initialized and forced using North American Regional Reanalyses (NARR). WRF-SCM atmospheric and LS ensembles are created by mixing the atmospheric and soil NARR profile centered on a given date with that from another day (randomly chosen from the same season) with weights drawn from a logit-normal distribution. Three types of one-week long numerical experiments are performed: (a) free ensemble runs; (b) ensemble assimilation that directly impacts the atmospheric-state vector only; (c) ensemble assimilation that directly impacts the coupled atmospheric-LS-state vector. The WRF-SCM is run in two modes: with and without inclusion of externally imposed horizontal advection terms in the atmospheric column (derived from the NARR, too). Preliminary examination of analyses and 30-min forecasts of reference height temperature and moisture, soil temperature and moisture at four depths (0.05m, 0.25m, 0.7m and 1.5m), fluxes at the surface, and planetary boundary layer (PBL) height shows that: 1. Horizontal advection is important to the realism of PBL heights and fluxes in the "truth", and affects the depth of influence of the assimilation on the soil state; a deeper effect (that could be non-realistic) is more often observed when advection is not included. 2. Inclusion of soil variables in the state vector can be beneficial to estimates of soil temperature and moisture,of moisture- and net latent heat fluxes at the surface, and of atmospheric variables (for the latter especially when no advection is included), However, no benefit is observed on PBL heights. Further analysis and improvement of the WRF-SCM/DART system (in particular the treatment of advection) is under way.

Rostkier-Edelstein, Dorita; Hacker, Joshua P.; Snyder, Chris

2014-05-01

309

ESCA study of oxidized wood surfaces  

SciTech Connect

Results of a preliminary study of the surface of wood exposed to outdoor weathering as well as to UV irradiation showed that ESCA provides valuable information and insight into the manifestation of weathering and photooxidation. From the ESCA spectra, the increase in signal intensities of carbon-oxygen bonds and oxygen-carbon-oxygen bonds (or unsaturated carbon oxygen bond) and oxygen-to-carbon ratio, and the decrease in carbon-carbon and carbon-hydrogen bonds of weathered and UV-irradiated wood surfaces suggested that wood surface was oxidized. Nevertheless, it was a superficial effect. Only a slow oxidation was observed at 100 ..mu..m under the exposed wood surfaces. From the oxygen-to-carbon ratio data, it revealed that weathered wood surface was rich in cellulose, poor in lignin. The leached-away degradation products from weathered wood surface accounted for the discrepancy between the ESCA line shapes of UV-irradiated and weathered wood surfaces.

Hon, D.N.S.

1984-09-01

310

Long-term snow and weather observations at Weissfluhjoch and its relation to other high-altitude observatories in the Alps  

NASA Astrophysics Data System (ADS)

Snow and weather observations at Weissfluhjoch were initiated in 1936, when a research team set a snow stake and started digging snow pits on a plateau located at 2,540 m asl above Davos, Switzerland. This was the beginning of what is now the longest series of daily snow depth, new snow height and bi-monthly snow water equivalent measurements from a high-altitude research station. Our investigations reveal that the snow depth at Weissfluhjoch with regard to the evolution and inter-annual variability represents a good proxy for the entire Swiss Alps. In order to set the snow and weather observations from Weissfluhjoch in a broader context, this paper also shows some comparisons with measurements from five other high-altitude observatories in the European Alps. The results show a surprisingly uniform warming of 0.8°C during the last three decades at the six investigated mountain stations. The long-term snow measurements reveal no change in mid-winter, but decreasing trends (especially since the 1980s) for the solid precipitation ratio, snow fall, snow water equivalent and snow depth during the melt season due to a strong temperature increase of 2.5°C in the spring and summer months of the last three decades.

Marty, Christoph; Meister, Roland

2012-12-01

311

Weather Creator  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What can you do to make it rain or even snow? 4. Does it always snow when ...

Kshumway

2009-09-28

312

Weathering Experiment  

NSDL National Science Digital Library

After discussing weathering and erosion in class, students are asked to do a small amount of research on different types of chemical weathering, physical weathering, and erosion processes (mostly out of their textbook). Outside of class students then dirty at least four similar dishes with the same type, thickness and aerial extent of food, preferably baked on to ensure maximum stick. One dish is set aside as a control (no weathering or erosion will occur for that dish). For each of the remaining three dishes, students devise an experiment that mimics some sort of chemical weathering, physical weathering, or erosion process (freeze/thaw, sand abrasion, oxidation, etc.). Prior to the experiments, the thickness of food is measured. Experiments are timed, and at the end of the experiment each plate is turned over to determine how much which method removed the greatest aerial extent of food. Experimental results are compared to the control plate to determine the actual effectiveness. Erosion/weathering rates are determined by dividing the thickness of food removed by the experimental time. Students then calculate how long it would take to remove a pile of food the size of the Geology building (assume a 50 m radius sphere), and to remove an amount of food equivalent to the depth of the Grand Canyon. Students then compare these results to rock erosion and weathering rates, performing similar calculations using these "real" rates (see the full project description for details). Photos of each step and the scientists are encouraged in their 2-3 page writeup.

Stelling, Pete

313

Gravestone Weathering  

NSDL National Science Digital Library

In this activity (located on pages 9-14 of PDF), learners visit a cemetery to examine the distinguishing characteristics of rock weathering. After researching stone weathering and acid rain, learners apply their knowledge to collect data related to chemical decomposition and physical disintegration at a cemetery site. This detailed lesson guide includes tips for educators, pre/post activity suggestions, hands-outs, and background information.

Wiberg, Leanne; History, National M.

2000-01-01

314

Experimental observation of dark solitons on the surface of water.  

PubMed

We present the first ever observation of dark solitons on the surface of water. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation. The shape and width of the soliton depend on the water depth, carrier frequency, and the amplitude of the background wave. The experimental data taken in a water tank show an excellent agreement with the theory. These results may improve our understanding of the nonlinear dynamics of water waves at finite depths. PMID:25166807

Chabchoub, A; Kimmoun, O; Branger, H; Hoffmann, N; Proment, D; Onorato, M; Akhmediev, N

2013-03-22

315

Cockpit weather information system  

NASA Technical Reports Server (NTRS)

Weather information, periodically collected from throughout a global region, is periodically assimilated and compiled at a central source and sent via a high speed data link to a satellite communication service, such as COMSAT. That communication service converts the compiled weather information to GSDB format, and transmits the GSDB encoded information to an orbiting broadcast satellite, INMARSAT, transmitting the information at a data rate of no less than 10.5 kilobits per second. The INMARSAT satellite receives that data over its P-channel and rebroadcasts the GDSB encoded weather information, in the microwave L-band, throughout the global region at a rate of no less than 10.5 KB/S. The transmission is received aboard an aircraft by means of an onboard SATCOM receiver and the output is furnished to a weather information processor. A touch sensitive liquid crystal panel display allows the pilot to select the weather function by touching a predefined icon overlain on the display's surface and in response a color graphic display of the weather is displayed for the pilot.

Tu, Jeffrey Chen-Yu (Inventor)

2000-01-01

316

Titan's Surface Composition from Cassini VIMS Solar Occultation Observations  

NASA Astrophysics Data System (ADS)

Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass < 3.0. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scatter-ing in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass < 3.0. The narrow 2.75-mm absorption feature, dividing the window into two sub-windows, present in all on-planet measurements is not present in the occultation data, and its strength is reduced at the cloud tops, suggesting the responsible molecule is concentrated in the lower troposphere or on the sur-face. Our empirical correction to Titan's surface reflectance yields properties shifted closer to water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is consistent with a mixture of typical Titan hydrocarbons and CO2, or possibly methane/ethane; the concentration mechanism proposed is something similar to a terrestrial playa lake evaporate deposit, based on the fact that river channels are known to feed into at least Hotei Regio.

McCord, Thomas; Hayne, Paul; Sotin, Christophe

2013-04-01

317

Observations of Strong Surface Radar Ducts over the Persian Gulf.  

NASA Astrophysics Data System (ADS)

Ducting of microwave radiation is a common phenomenon over the oceans. The height and strength of the duct are controlling factors for radar propagation and must be determined accurately to assess propagation ranges. A surface evaporation duct commonly forms due to the large gradient in specific humidity just above the sea surface; a deeper surface-based or elevated duct frequently is associated with the sudden change in temperature and humidity across the boundary layer inversion.In April 1996 the U.K. Meteorological Office C-130 Hercules research aircraft took part in the U.S. Navy Ship Antisubmarine Warfare Readiness/Effectiveness Measuring exercise (SHAREM-115) in the Persian Gulf by providing meteorological support and making measurements for the study of electromagnetic and electro-optical propagation. The boundary layer structure over the Gulf is influenced strongly by the surrounding desert landmass. Warm dry air flows from the desert over the cooler waters of the Gulf. Heat loss to the surface results in the formation of a stable internal boundary layer. The layer evolves continuously along wind, eventually forming a new marine atmospheric boundary layer. The stable stratification suppresses vertical mixing, trapping moisture within the layer and leading to an increase in refractive index and the formation of a strong boundary layer duct. A surface evaporation duct coexists with the boundary layer duct.In this paper the authors present aircraft- and ship-based observations of both the surface evaporation and boundary layer ducts. A series of sawtooth aircraft profiles map the boundary layer structure and provide spatially distributed estimates of the duct depth. The boundary layer duct is found to have considerable spatial variability in both depth and strength, and to evolve along wind over distances significant to naval operations (100 km). The depth of the evaporation duct is derived from a bulk parameterization based on Monin-Obukhov similarity theory using near-surface data taken by the C-130 during low-level (30 m) flight legs and by ship-based instrumentation. Good agreement is found between the two datasets. The estimated evaporation ducts are found to be generally uniform in depth; however, localized regions of greatly increased depth are observed on one day, and a marked change in boundary layer structure resulting in merging of the surface evaporation duct with the deeper boundary layer duct was observed on another. Both of these cases occurred within exceptionally shallow boundary layers (100 m), where the mean evaporation duct depths were estimated to be between 12 and 17 m. On the remaining three days the boundary layer depth was between 200 and 300 m, and evaporation duct depths were estimated to be between 20 and 35 m, varying by just a few meters over ranges of up to 200 km.The one-way radar propagation factor is modeled for a case with a pronounced change in duct depth. The case is modeled first with a series of measured profiles to define as accurately as possible the refractivity structure of the boundary layer, then with a single profile collocated with the radar antenna and assuming homogeneity. The results reveal large errors in the propagation factor when derived from a single profile.

Brooks, Ian M.; Goroch, Andreas K.; Rogers, David P.

1999-09-01

318

The surface composition and photometric properties of 21 Lutetia as observed by VIRTIS onboard ROSETTA  

NASA Astrophysics Data System (ADS)

The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard Rosetta has successfully returned spatially-resolved 0.4-5.1 ?m hyperspectral data as well as high spectral resolution 2-5 ?m data of the main belt asteroid 21 Lutetia during the July 2010 fly-by. At the time of the data analysis for our first paper on the Lutetia's results (Coradini et al., Science in press) we were not able to perform any photometric correction due to the limited accuracy of the spacecraft orbit and attitude reconstruction from flight data. This implied that, for instance, we could not account for any subtle color variegation on the surface of the asteroid. On the contrary the Osiris team reported (Sierks et al, Science in Press) a reflectivity variation of up to 30%, in some spectral bands, inside craters located in the Baetica region. Using corrected S/C trajectory and attitude kernels derived from the combination of Virtis and Miro data, we are now in the position to verify Osiris findings and to extend them to a more thorough spectral coverage, removing the effect of variation in illumination conditions due to the real shape of the asteroid and to the local topography. The Hapke's light scattering theory can be applied to the spectral reflectance in the range were the radiance is not affected by the thermal emission contribution from the surface (the analysis of the thermal region is part of a separate work, Keihm et al, EPSC-DPS2011-39, 201, and shall not be treated here). The phase angle coverage is suitable to this task as it covers from 0° up to 140°, thus providing good constraints on the true reflectance (single scattering albedo) of the materials making up the surface as well as on the other parameters related to the scattering properties of the regolith. This analysis permits to determine the presence and surface coverage of any weathering products, at least in the region observed by Virtis which extend to from North pole to the equatorial regions. The analysis allows to verify preliminary evaluation of the Lutetia data which gave a clear phase reddening of the IR spectrum in the range 1.2-2.3 ?m with a slope of 1.3x10-3 /deg. It allows also to put Lutetia in the context of the previous asteroid in-situ observations (951 Gaspra, 243 Ida, 433 Eros) for which color variation as well as albedo variations were observed and quantified across the surface.

Capaccioni, F.; Coradini, A.; Erard, S.; Tosi, F.; Filacchione, G.; De sanctis, M.; Capria, M. T.; Kamp, L.; Keihm, S. J.; Gulkis, S.; Arnold, G.; Ammannito, E.; Barucci, A.; Giuppi, S.

2011-12-01

319

An estimation of snow accumulation on Svalbard glaciers on the basis of standard weather-station observations  

NASA Astrophysics Data System (ADS)

Winter precipitation in the form of snow is the major factor determining accumulation on Arctic glaciers. In this paper, I present a simple method to assess snow accumulation on the glaciers of Svalbard. I deduce snow accumulation from the sum of winter precipitation and the fraction of precipitation of different types at a reference weather station. The accumulation is then converted to a relevant point on the glacier, using an accumulation gradient and a location coefficient. I apply this algorithm of accumulation assessment to eight glaciers of southern and central Spitsbergen using data from 23 seasons. On the basis of measured accumulation data, the mean error of the calculated accumulation, with no distinction of precipitation types, amounted to 23%. When the distinction between precipitation types is used for glaciers of southern Spitsbergen, the average error of estimation was 19%. Errors result from factors influencing accumulation distribution over the glacier elevation profile (e.g. glacier topography, orography of its surroundings, precipitation inversion). Application of this accumulation algorithm may provide a crucial method of estimating mass balance for glaciers not included in permanent monitoring.

Grabiec, Mariusz

320

Stratocumulus cloud height variations determined from surface and satellite observations  

NASA Technical Reports Server (NTRS)

Determination of cloud-top heights from satellite-inferred cloud-top temperatures is a relatively straightforward procedure for a well-behaved troposphere. The assumption of a monotonically decreasing temperature with increasing altitude is commonly used to assign a height to a given cloud-top temperature. In the hybrid bispectral threshold method, or HBTM, Minnis et al. (1987) assume that the lapse rate for the troposphere is -6.5/Kkm and that the surface temperature which calibrated this lapse rate is the 24 hour mean of the observed or modeled clear-sky, equivalent blackbody temperature. The International Satellite Cloud Climatology Project (ISCCP) algorithm (Rossow et al., 1988) attempts a more realistic assignment of height by utilizing interpolations of analyzed temperature fields from the National Meteorological Center (NMC) to determine the temperature at a given level over the region of interest. Neither these nor other techniques have been tested to any useful extent. The First ISCCP Regional Experiment (FIRE) Intensive Field Observations (IFO) provide an excellent opportunity to assess satellite-derived cloud height results because of the availability of both direct and indirect cloud-top altitude data of known accuracy. The variations of cloud-top altitude during the Marine Stratocumulus IFO (MSIFO, June 29 to July 19, 1987) derived from surface, aircraft, and satellite data are examined.

Minnis, Patrick; Young, David F.; Davies, R.; Blaskovic, M.; Albrecht, Bruce A.

1990-01-01

321

Oil sheen weathering post Deepwater Horizon  

NASA Astrophysics Data System (ADS)

A recently published study identified the source of the reoccurred oil sheens close to the Deepwater Horizon (DWH) disaster site as a finite contamination most likely derived from tanks and pits on the DWH wreckage itself. Here we use geochemical fingerprinting and microbial community analysis to better understand the fate and weathering processes affecting these surface oils. Both, alkanes and polycyclic aromatic hydrocarbons (PAHs) are shown to reflect a linear decrease of hydrocarbon compounds with increasing distance to the DWH wreckage site (equivalent to exposure time on the sea surface). These results indicate that in the early stage of weathering the combined effects of dissolution and evaporation dominate the degradation of these surface oils. Sheen microbial communities were dominated by Cyanobacteria, Planctomycetes, Verrucomicrobia, Flavobacteria, Alphaproteobacteria, and Deltaproteobacteria, with low relative abundances of Gammaproteobacteria likely to be hydrocarbon degraders (no more than 15% of sequences in each sample). However, some of these Gammaproteobacteria were closely related to putative hydrocarbon degraders observed in abundance in deep water plumes during the primary Deepwater Horizon spill, suggesting that very low levels of biodegradation may be also occurring. This in situ weathering experiment provides new insights in hydrocarbon weathering dynamics and shows how chemical and biological changes can potentially be masked by large evaporative losses of compounds smaller than C18 n-alkanes.

Kellermann, M. Y.; Redmond, M. C.; Reddy, C. M.; Aeppli, C.; Nelson, R. K.; Valentine, D. L.

2013-12-01

322

Evaluation of sea-surface salinity observed by Aquarius  

NASA Astrophysics Data System (ADS)

salinity (SSS) observed by Aquarius was compared with global observations from Argo floats and offshore moored buoys to evaluate the quality of satellite SSS data and to assess error structures. Aquarius products retrieved by different algorithms (Aquarius Official Release version 3.0 [V3.0], Combined Active-Passive [CAP] algorithm version 3.0, and Remote Sensing Systems test bed algorithm version 3) were compared. The Aquarius SSS was in good agreement with in situ salinity measurements for all three products. Root-mean-square (rms) differences of the salinity residual, with respect to Argo salinity, ranged from 0.41 to 0.52 psu. These three Aquarius products exhibit high SSS deviation from Argo salinity under lower sea-surface temperature conditions (<10°C) due to lower sensitivity of microwave emissivity to SSS. The CAP product deviates under strong wind conditions (>10 m s-1), probably due to model bias and uncertainty associated with sea-surface roughness. Furthermore, significant SSS differences between ascending (south-to-north) and descending (north-to-south) paths were detected. The monthly averaged Aquarius SSS (1° × 1° grid) was also compared with outputs from the ocean data optimal interpolation (OI) system operated by the Japan Agency for Marine-Earth Science Technology (JAMSTEC) and the ocean data assimilation system used by the Meteorological Research Institute, Japan Meteorological Agency (MRI/JMA). Negative bias, attributed to near-surface salinity stratification by precipitation, was detected in tropical regions. For 40°S-40°N, rms difference, with respect to JAMSTEC OI, is 0.27 psu for the V3.0, while the CAP product rms difference is only 0.22 psu, which is close to the Aquarius mission goal.

Abe, Hiroto; Ebuchi, Naoto

2014-11-01

323

Weathering and weathering rates of natural stone  

NASA Astrophysics Data System (ADS)

Physical and chemical weathering were studied as separate processes in the past. Recent research, however, shows that most processes are physicochemical in nature. The rates at which calcite and silica weather by dissolution are dependent on the regional and local climatic environment. The weathering of silicate rocks leaves discolored margins and rinds, a function of the rocks' permeability and of the climatic parameters. Salt action, the greatest disruptive factor, is complex and not yet fully understood in all its phases, but some of the causes of disruption are crystallization pressure, hydration pressure, and hygroscopic attraction of excess moisture. The decay of marble is complex, an interaction between disolution, crack-corrosion, and expansion-contraction cycies triggered by the release of residual stresses. Thin spalls of granites commonly found near the street level of buildings are generally caused by a combination of stress relief and salt action. To study and determine weathering rates of a variety of commercial stones, the National Bureau of Standards erected a Stone Exposure Test Wall in 1948. Of the many types of stone represented, only a few fossiliferous limestones permit a valid measurement of surface reduction in a polluted urban environment.

Winkler, Erhard M.

1987-06-01

324

Species formed at cuprite fracture surfaces; observation of O 1 s surface core level shift  

NASA Astrophysics Data System (ADS)

Surfaces of mineral cuprite prepared by fracture under UHV have been characterised by synchrotron XPS and near-edge X-ray absorption spectroscopy before and after exposure to ambient air. Before exposure of the cuprite, the Cu 2 p photoelectron and Cu L 2,3-edge absorption spectra were consistent with Cu I with very little d9 character. Surface-enhanced O 1 s spectra from the unexposed mineral revealed a surface species, with binding energy 0.95 ± 0.05 eV below the principal cuprous oxide peak, assigned to under-coordinated oxygen. A second surface species, with binding energy about 1 eV higher than the principal peak, was assigned to either hydroxyl derived from chemisorbed water vapour or surface oxygen dimers produced by restructuring of the cuprite fracture surface. The width of the principal O 1 s peak was 0.66 ± 0.02 eV. The observed Cu L 3- and O K-edge absorption spectra were in good agreement with those simulated for the cuprite structure. After exposure of the fracture surface to ambient air, the low binding energy O 1 s surface species was barely discernible, the original high binding energy O 1 s surface species remained of comparable intensity, new intensity appeared at an even higher (˜1.9 eV) binding energy, and the Cu L 2,3-edge spectrum indicated the presence of Cu II, consistent with the formation of a thin surface layer of Cu(OH) 2.

Harmer, Sarah L.; Skinner, William M.; Buckley, Alan N.; Fan, Liang-Jen

2009-02-01

325

Weathering and mass wasting  

NSDL National Science Digital Library

This class exercise is an opportunity for students to apply textbook information about weathering and mass wasting to local and nationally-recognized surface features, such as Stone Mountain (GA), Half Dome (CA), and others. It also serves as an introduction to the use of Google Earth as an analytical tool for calculating distances, slopes, and evaluating landforms. Designed for a geomorphology course

Clayton, Jordan

326

Microbial Weathering of Olivine  

NASA Technical Reports Server (NTRS)

Controlled microbial weathering of olivine experiments displays a unique style of nanoetching caused by biofilm attachment to mineral surfaces. We are investigating whether the morphology of biotic nanoetching can be used as a biosignature. Additional information is contained in the original extended abstract.

McKay, D. S.; Longazo, T. G.; Wentworth, S. J.; Southam, G.

2002-01-01

327

Space Weather and Management of Environmental Risks and Hazards  

NASA Astrophysics Data System (ADS)

"Space Weather" is defined as electromagnetic and particle conditions in the space environment that can disturb space-borne and ground-based technological systems (e.g. satellite operation, telecommunication, aviation, electric power transmission) and even endanger human health. Thus, space weather is of great importance to the society since people are dependent on reliable operation of modern technology, interruptions of which may lead to large economical and other losses. Physical processes involved in space weather constitute a complicated chain from the Sun to the Earth's surface. Thus, a full understanding of space weather and the risks it produces requires expertise in many different disciplines of science and technology. Space weather is a new subject among the natural risks and hazards which threaten the society and its infrastructure (although the first observations of ground effects of space weather were already made about 150 years ago). Monitoring systems for the management of other risks, such as floods, forest fires, etc., and for security are, to a great extent, based on satellite observations. Spacecraft and the communication between satellites and the ground are vulnerable to space weather. Thus, besides being a direct risk to technological systems, space weather may also be indirectly adverse to risk management. These two aspects of space weather are considered in a proposal to be submitted to EU's Sixth Framework Programme under the "Aeronautics and Space" priority in the "Global Monitoring for Environment and Security (GMES) / Risk Management" area in March 2004. The proposal coordinated by the Finnish Meteorological Institute with five to ten participating institutes is called SW-RISK ("Space Weather - Risk Indices from Scientific Know-how").

Pirjola, R.; Kauristie, K.; Lappalainen, H.

328

Severe Weather Forecast Decision Aid  

NASA Technical Reports Server (NTRS)

This report presents a 15-year climatological study of severe weather events and related severe weather atmospheric parameters. Data sources included local forecast rules, archived sounding data, Cloud-to-Ground Lightning Surveillance System (CGLSS) data, surface and upper air maps, and two severe weather event databases covering east-central Florida. The local forecast rules were used to set threat assessment thresholds for stability parameters that were derived from the sounding data. The severe weather events databases were used to identify days with reported severe weather and the CGLSS data was used to differentiate between lightning and non-lightning days. These data sets provided the foundation for analyzing the stability parameters and synoptic patterns that were used to develop an objective tool to aid in forecasting severe weather events. The period of record for the analysis was May - September, 1989 - 2003. The results indicate that there are certain synoptic patterns more prevalent on days with severe weather and some of the stability parameters are better predictors of severe weather days based on locally tuned threat values. The results also revealed the stability parameters that did not display any skill related to severe weather days. An interactive web-based Severe Weather Decision Aid was developed to assist the duty forecaster by providing a level of objective guidance based on the analysis of the stability parameters, CGLSS data, and synoptic-scale dynamics. The tool will be tested and evaluated during the 2005 warm season.

Bauman, William H., III; Wheeler, Mark M.; Short, David A.

2005-01-01

329

Upgrade Summer Severe Weather Tool in MIDDS  

NASA Technical Reports Server (NTRS)

The goal of this task was to upgrade the severe weather database from the previous phase by adding weather observations from the years 2004 - 2009, re-analyze the data to determine the important parameters, make adjustments to the index weights depending on the analysis results, and update the MIDDS GUI. The added data increased the period of record from 15 to 21 years. Data sources included local forecast rules, archived sounding data, surface and upper air maps, and two severe weather event databases covering east-central Florida. Four of the stability indices showed increased severe weather predication. The Total Threat Score (TTS) of the previous work was verified for the warm season of 2009 with very good skill. The TTS Probability of Detection (POD) was 88% and the False alarm rate (FAR) of 8%. Based on the results of the analyses, the MIDDS Severe Weather Worksheet GUI was updated to assist the duty forecaster by providing a level of objective guidance based on the analysis of the stability parameters and synoptic-scale dynamics.

Wheeler, Mark M.

2010-01-01

330

Reading Weather Maps  

NSDL National Science Digital Library

From the University of Illinois at Urbana-Champaign's Department of Atmospheric Sciences comes the Reading Weather Maps Web site. Visitors learn how to convert their local time to the standard used by all meteorologists; to tell the difference between Kelvin, Celsius, and Fahrenheit temperatures; and how to read maps with weather data collected on and above the Earth's surface. For example, wind bards, which are flag-like symbols that indicate wind direction and wind speed, always point in the direction the wind is blowing "from." Other interesting facts, descriptions, and illustrations are available on the site.

1969-12-31

331

Monitoring moisture dynamics in weathered, fractured bedrock  

NASA Astrophysics Data System (ADS)

Variably weathered, fractured bedrock underlying hillslopes influences runoff pathways, moisture availability, and slope stability yet direct measurement of moisture dynamics within this zone remains challenging. Established methods for monitoring moisture content in soils are not easily transferrable to fractured rock environments due to inaccessibility and the difficulties associated with the installation and calibration of sensors. At a steep, intensively instrumented hillslope in coastal northern California we explore 7 methods of varying spatial scale and temporal frequency to document moisture dynamics in weathered, fractured argillite bedrock. The forested 4000 m2 catchment is mantled by approximately 50 cm of soil and underlain by a thick weathered bedrock zone which extends to 25 m at the ridge top and thins downslope to a depth of 4 m. The Mediterranean climate at the site is characterized by cool, wet winters and warm, dry summers receiving most of the annual precipitation (1900 mm on average) between October and May. The following measurement methods are employed at the site: 1) downhole neutron moisture logging (CPN 503DR Hydroprobe) in 12 wells, 6-35 m deep 2) time domain reflectometer probes (TDR100, Campbell Scientific) installed in trenches and augured holes of varying backfill material 3) capacitance sensors (SM200, Dynamax, Inc) installed near the surface 4) electrical resistance sensor array systems (ERSAS) installed in augured and backfilled holes, 5) time lapse, non-invasive electrical resistivity tomography, 6) pressure transducers installed in deep wells and 7) laboratory gravimetric measurements of samples collected in augured holes and wells. Our observations highlight how each measurement method individually or collectively contributes to the understanding of moisture dynamics and runoff processes in fractured, weathered bedrock. We found that though backfill material and well casing significantly influence the magnitude of the measured response, using the timing of the response and manufacturer or site specific calibration, allowed us to effectively quantify moisture storage and transport rates in the weathered bedrock. We found that in response to rainfall, all water passes through the soil and weathered bedrock at the site and perches above the fresh bedrock before it travels laterally downslope. The rapid water table response to the first storm events of the season often occurs before the wetting front progresses through the first few meters of the weathered profile. Though shallower weathered bedrock wets and dries annually, deeper portions of the weathered bedrock zone do not show significant seasonal changes in moisture content. As investigations of the critical zone extend deeper, robust techniques for monitoring moisture in weathered bedrock are needed to quantify the significance of rock moisture in hydrologic and geomorphic processes.

Rempe, D. M.; Salve, R.; Oshun, J.; Dietrich, W. E.

2013-12-01

332

Surface observations for monitoring urban fossil fuel CO2 emissions: Minimum site location requirements for the Los Angeles megacity  

NASA Astrophysics Data System (ADS)

The contemporary global carbon cycle is dominated by perturbations from anthropogenic CO2 emissions. One approach to identify, quantify, and monitor anthropogenic emissions is to focus on intensely emitting urban areas. In this study, we compare the ability of different CO2 observing systems to constrain anthropogenic flux estimates in the Los Angeles megacity. We consider different observing system configurations based on existing observations and realistic near-term extensions of the current ad hoc network. We use a high-resolution regional model (Stochastic Time-Inverted Lagrangian Transport-Weather Research and Forecasting) to simulate different observations and observational network designs within and downwind of the Los Angeles (LA) basin. A Bayesian inverse method is employed to quantify the relative ability of each network to improve constraints on flux estimates. Ground-based column CO2 observations provide useful complementary information to surface observations due to lower sensitivity to localized dynamics, but column CO2 observations from a single site do not appear to provide sensitivity to emissions from the entire LA megacity. Surface observations from remote, downwind sites contain weak, sporadic urban signals and are complicated by other source/sink impacts, limiting their usefulness for quantifying urban fluxes in LA. We find a network of eight optimally located in-city surface observation sites provides the minimum sampling required for accurate monitoring of CO2 emissions in LA, and present a recommended baseline network design. We estimate that this network can distinguish fluxes on 8 week time scales and 10 km spatial scales to within ~12 g C m-2 d-1 (~10% of average peak fossil CO2 flux in the LA domain).

Kort, Eric A.; Angevine, Wayne M.; Duren, Riley; Miller, Charles E.

2013-02-01

333

Evaluating China's black carbon emissions using surface observations: sensitivity to observation representativeness and transport model error  

NASA Astrophysics Data System (ADS)

Atmospheric measurements of BC concentrations at representative locations provide invaluable independent datasets to evaluate bottom-up BC emissions, particularly when used in conjunction with chemical transport models. A few studies have evaluated China's BC emission inventory using surface observations, but their 'top-down' estimates of Chinese BC emissions vary greatly. This study examines the sensitivity of 'top-down' quantification of Chinese BC emissions to the choice of observational data and to transport model errors associated with grid resolution, wet deposition, and transport. Using hourly measurements of BC obtained with optical methods at two rural sites in China (Miyun and Chongming), we performed a detailed analysis of the model-observation comparison to filter out those observations not representative of regional emissions or heavily influenced by the model's transport errors instead of by emissions. The observed BC to CO correlation and its variation with precipitation were used to evaluate the model's wet deposition process and to quantify the wet deposition bias on BC emission estimate. By comparing top-down BC emission estimate derived from carefully-selected hourly observations with that from mere monthly-mean observations, we provided the error estimate for top-down emissions due to observation representativeness and model error. After better quantifying these errors, we evaluated China's bottom-up BC inventory of Zhang et al. [2009] by region and found that this inventory underestimated BC emissions from Center China, North China Plain and Yangtze River Delta region while overestimated emissions from Northeast China and Center South China. Our top-down estimate of BC emissions over China as a whole is 20%-40% higher than the bottom-up inventory.

Wang, Y.; Wang, X.; Hao, J.; Kondo, Y.; Irwin, M.; Munger, J. W.; Zhao, Y.

2012-12-01

334

Observed near-surface currents under four super typhoons  

NASA Astrophysics Data System (ADS)

The upper ocean currents under four category-5 (super) typhoons [Chaba (2004), Maon (2004), Saomai (2006), and Jangmi (2008)] were studied using data from four drifters of the Surface Velocity Program (SVP) (Niiler, 2001) in the northwestern Pacific. Maximum current velocities occurring to the right of the super typhoon tracks were observed as 2.6 m s- 1 for slow-moving (2.9 m s- 1) Maon, 2.1 m s- 1 for typical-moving Chaba (5.1 m s- 1), 1.4 m s- 1 for fast-moving Jangmi (6.8 m s- 1), and 1.2 m s- 1 for fast-moving Saomai (8.1 m s- 1). Furthermore, dependence of the mixed layer current velocity under a super typhoon on its translation speed and statistical relationships between the maximum current speed and the Saffir-Simpson hurricane scale are also provided.

Chang, Yu-Chia; Chu, Peter C.; Centurioni, Luca R.; Tseng, Ruo-Shan

2014-11-01

335

Space Weather  

NSDL National Science Digital Library

With three levels to choose from on each page - beginner, intermediate or advanced - this site provides information on Space Weather and the terms scientists use to describe the everchanging conditions in space. Explosions on the Sun create storms of radiation, fluctuating magnetic fields, and swarms of energetic particles. These phenomena travel outward through the Solar System with the solar wind. Upon arrival at Earth, they interact in complex ways with Earth's magnetic field, creating Earth's radiation belts and the Aurora. Some space weather storms can damage satellites, disable electric power grids, and disrupt cell phone communications systems. This site provides images, activities, and interesting facts about all of these events.

2004-02-06

336

Wild Weather  

NSDL National Science Digital Library

In this online, interactive module, students learn about severe weather (thunderstorms, hurricanes, tornadoes, and blizzards) and the key features for each type of "wild weather" using satellite images. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

337

Simulations of winter blocking episodes using observed sea surface temperatures  

NASA Technical Reports Server (NTRS)

The formation of major Northern Hemisphere blockings during January 1979 is studied in numerical simulations of the global atmosphere with a sea surface temperature (SST) field updated with observations during the model integration. Both the standard 4 x 5 degrees latitude-longitude and high-resolution 2 x 2.5 degrees versions of the Goddard Laboratory for Atmospheres general circulation models (GCMs) are employed. The SST field is provided by a blend analysis of in situ and satellite-retrieved data. The simulations by the high-resolution GCM with a realistic SST field of the ocean surface are shown to be capable of producing two successive realistic major blockings in the Pacific and Atlantic through a one-month period. The skill in predicting the blocking formation as obtained in the simulations is due to improved skill in forecasting of ultralog waves. Although the results are encouraging, only one initial state is involved in this series of simulations; therefore, the results should not be generalized yet at this stage of investigation.

Kung, Ernest C.; Dacamara, Carlos C.; Baker, Wayman E.; Susskind, Joel; Park, Chung-Kyu

1990-01-01

338

Observations of Lightning on Earth from the Lunar Surface  

NASA Technical Reports Server (NTRS)

The NASA Optical Transient Detector (OTD) launched into a 70deg inclination orbit in April 1995 aboard the MicroLab-1 satellite and the Lightning Imaging Sensor (LIS) launched into a 35deg inclination orbit in November 1997 (and still operating today) aboard the Tropical Rainfall Measuring Mission have produced the most comprehensive global observations of lightning activity on Earth. The OTD collected data for 5-yr from an altitude of 740 km while the LIS, in its 10th year of operations, is still collecting data from its current altitude of 402 km. From these altitudes the OTD observes an individual storm within its field of view for approx.3 min and the LIS for approx.90 sec as the satellites orbit the earth. Figures 1-4 show the combined LIS/OTD distribution of lightning for day and night during the Northern Hemisphere warm season from April through August (Fig. 1,2) and the cool season from October through February (Fig. 3,4) as might be observed from the lunar surface (12-h daylight and 12-h nighttime observations). The day and night plots are for the twelve hour periods centered on local noon and midnight. The total viewtime of the global lightning activity is 200 hours or less, depending on latitude (Fig. 5). Most of the observed lightning occurs over the northern hemisphere land areas as reported in previous studies. More lightning activity is seen at the higher northern latitudes during the day. The greatest lightning maxima occurs in the southeastern US, during the day. The corresponding region at night shows much less lightning activity. In contrast, there is a maxima in lightning activity at night over the high Plains area of the U.S. This region had lower lightning rates during the daytime period. During the cold season, the southern hemisphere has significantly more lightning. The maxima in Central Africa is still present, and a secondary maxima is observed in South Africa. In South America, the maxima in Argentina occurs at night in association with large-scale mesoscale convective storm complexes. This is the region on the earth having the greatest frequency of extreme storms with flash rates exceeding 1000 flashes/min. daytime maxima is seen extending from Northern Argentina to Brazil. In the US., the Gulf of Mexico and the Gulf Coast states exhibit a maximum in lightning activity both day and night.

Goodman, S. J.; Buechler, D. E.; Christian, H. J., Jr.; Stahl, H. P.

2007-01-01

339

Space Weathering on Icy Satellites in the Outer Solar System  

NASA Astrophysics Data System (ADS)

Space weathering produces well-known optical effects in silicate minerals in the inner Solar System, for example, on the Moon. Space weathering from solar wind and UV is expected to be weaker in the outer Solar System simply because intensities are lower. However, cosmic rays from inner to outer solar system would be similar to first order. Similarly with micrometeoroid bombardment. That, combined with the much higher volatility of icy surfaces means there is the potential for space weathering on icy outer Solar System surfaces to show optical effects. The Cassini spacecraft orbiting Saturn is providing evidence for space weathering on icy bodies. The Cassini VIMS instrument has spatially mapped satellite surfaces and the rings from .35-5 microns and the UVIS instrument from 0.1 to 0.2 microns. These data have sampled a complex mixing space between H2O ice and non-ice components and they show some common spectral properties. Similarly, spectra of the icy Galilean satellites and satellites in the Uranian system have some commonality in spectral properties with those in the Saturn system. The UV absorber is spectrally similar on many surfaces. VIMS has identified CO2, H2 and trace organics in varying abundances on Saturn's satellites. We postulate that through the spatial relationships of some of these compounds that they are created and destroyed through space weathering effects. For example, the trapped H2 and CO2 observed by VIMS in regions with high concentrations of dark material may in part be space weathering products from the destruction of H2O and organic molecules. The dark material, particularly on Iapetus which has the highest concentration in the Saturn system, is well matched by space-weathered silicates in the .4-2.6 micron range, and the spectral shapes closely match those of the most mature lunar soils, another indicator of space weathered material.

Clark, Roger N.; Perlman, Zachary; Pearson, Neil; Cruikshank, Dale P.

2014-11-01

340

Gemini near-infrared observations of Europa's Hydrated Surface Materials  

NASA Astrophysics Data System (ADS)

Europa is a highly dynamic icy moon of Jupiter. It is thought the moon harbors a subsurface ocean, with the potential to sustain life, with Europa being a key target of ESA's forthcoming Jupiter Icy Moons Orbiter (JUICE) mission. However, much is not known concerning the chemistry of the subsurface ocean. The surface is dominated by water ice, with a hydrated non-ice material component providing the distinctive albedo contrasts seen at visible and near-infrared wavelengths. These non-ice materials are concentrated at disrupted surface regions, providing a diagnostic probe for the chemistry and characteristics of the liquid ocean beneath. Leading but potentially competing theories on the composition of these hydrated non-ice materials suggest either sulfuric acid-water mixtures (Carlson et al., 1999) or hydrated magnesium/sodium salts (McCord et al., 1999). Recent reanalysis of Galileo-NIMS observations suggest a mixture of both - hydrated salts are present at all longitudes but the sulfuric acid hydrates are localized on the trailing side. We present preliminary analysis of new ground-based Gemini disk-resolved spectroscopy of Europa using the Near-Infrared Integrated Field Spectrometer (NIFS), taken in late 2011, at H (1.49 - 1.80 ?m) and K bands (1.99 - 2.40 ?m) with spectral resolving powers of ~ 5300. At these NIR wavelengths, with spectral resolution much better than Galileo-NIMS, the spectral absorption and continuum characteristics of these ice and non-ice materials can be separated out. In addition, the spatial resolution potentially allows identification of localized materials whose signature would be diluted in disk-integrated spectra. These observations of the trailing hemisphere use Altair adaptive optics to achieve spatial resolutions of 0.1" (~310 km per pixel) or better, potentially leading to better identification of the non-ice materials and their spatial distributions. References Carlson, R.W., R.E. Johnson, and M.S. Anderson 1999. Sulfuric acid on Europa and the radiolytic sulfur cycle. Science 286, 97-99. McCord, T. et al. 1999. Hydrated salt minerals on Europa's surface from the Galileo Near- Infrared Mapping Spectrometer (NIMS) investigation. J. Geophys. Res. 104, 11827

Tsang, C.; Spencer, J. R.; Grundy, W. M.; Dalton, J. B.

2012-12-01

341

Observing System Simulation Experiments to Determine the Potential Impact of Space-Based Lidar Wind Profiles on Weather Prediction  

NASA Technical Reports Server (NTRS)

Observing system simulation experiments (OSSE's) provide an effective means to evaluate the potential impact of a proposed observing system, as well as to determine tradeoffs in their design, and to evaluate data assimilation methodology. Great care must be taken to ensure realism of the OSSE's, and in the interpretation of OSSE results. All of the OSSE's that have been conducted to date have demonstrated tremendous potential for space-based wind profile data to improve atmospheric analyses, forecasts, and research. This has been true for differing data assimilation systems, analysis methodology, and model resolutions. OSSE's clearly show much greater potential for observations of the complete wind profile than for single-level wind data or observations of the boundary layer alone.

Atlas, Robert

2003-01-01

342

Wacky Weather  

NSDL National Science Digital Library

This 5-lesson unit gives students practice in using calculating, graphing and modeling skills to analyze varoius aspects of weather. Students calculate fractions of a set of rainfall data, graph damage costs of selected hurricanes, and make Venn diagrams to compare droughts and hurricanes. Visuals and student handouts are provided.

Barbara Chichetti

2002-01-01

343

Today's Weather  

NSDL National Science Digital Library

This activity is part of Planet Diary and contains an online exploration of weather maps. Students use current maps to learn about and locate different features such as low-pressure areas and fronts. They then explore how these are related to severe storms.

344

Wonderful Weather  

NSDL National Science Digital Library

In this activity, learners conduct three experiments to examine temperature, the different stages of the water cycle, and how convection creates wind. These activities can be used individually or as a group for a lesson on weather. Note: boiling water is required for this activity; adult supervision required.

Mission Science Workshop

2013-01-01

345

Weather Stations  

NSDL National Science Digital Library

This is a series of seven brief activities about Jupiter's atmosphere and weather. Learners will look at Jupiter's distinct banded appearance, violent storms, and clouds of many different colors. The activities are part of Explore! Jupiter's Family Secrets, a series designed to engage children in space and planetary science in libraries and informal learning environments.

346

Quantification of physical weathering rates using thermodynamics  

Microsoft Academic Search

Physical weathering plays an important role in the global rock cycle in that it breaks up primary rock, thereby increasing the surface area for chemical weathering and providing the substrate for soil formation. We use a simple, thermodynamics based approach to quantify magnitudes of weathering, their spatial variation across climatic regions and their sensitivity to climatic change. Our approach is

F. Gans; S. Arens; S. J. Schymanski; A. Kleidon

2010-01-01

347

Tacoma Power Weatherization  

E-print Network

Tacoma Power Weatherization Specifications August 2009 KnowYourPower.com | #12;TACOMA POWER WEATHERIZATION SPECIFICATIONS 2009 edition Page 2 #12;TACOMA POWER WEATHERIZATION SPECIFICATIONS 2009 edition

348

Observational effects of magnetism in O stars: surface nitrogen abundances  

NASA Astrophysics Data System (ADS)

Aims: We investigate the surface nitrogen content of the six magnetic O stars known to date as well as of the early B-type star ? Sco. We compare these abundances to predictions of evolutionary models to isolate the effects of magnetic field on the transport of elements in stellar interiors. Methods: We conduct a quantitative spectroscopic analysis of the sample stars with state-of-the-art atmosphere models. We rely on high signal-to-noise ratio, high resolution optical spectra obtained with ESPADONS at CFHT and NARVAL at TBL. Atmosphere models and synthetic spectra are computed with the code CMFGEN. Values of N/H together with their uncertainties are determined and compared to predictions of evolutionary models. Results: We find that the magnetic stars can be divided into two groups: one with stars displaying no N enrichment (one object); and one with stars most likely showing extra N enrichment (5 objects). For one star (?1 Ori C) no robust conclusion can be drawn due to its young age. The star with no N enrichment is the one with the weakest magnetic field, possibly of dynamo origin. It might be a star having experienced strong magnetic braking under the condition of solid body rotation, but its rotational velocity is still relatively large. The five stars with high N content were probably slow rotators on the zero age main sequence, but they have surface N/H typical of normal O stars, indicating that the presence of a (probably fossil) magnetic field leads to extra enrichment. These stars may have a strong differential rotation inducing shear mixing. Our results should be viewed as a basis on which new theoretical simulations can rely to better understand the effect of magnetism on the evolution of massive stars. Based on observations collected at the CFHT and the Télescope Bernard Lyot.Appendix A is available in electronic form at http://www.aanda.org

Martins, F.; Escolano, C.; Wade, G. A.; Donati, J. F.; Bouret, J. C.; Mimes Collaboration

2012-02-01

349

Weather radar research at the USA's storm laboratory  

NASA Technical Reports Server (NTRS)

Radar research that is directed toward improving storm forecasts and hazard warnings and studying lightning is discussed. The two moderately sensitive Doppler weather radars in central Oklahoma, with their wide dynamic range, have demonstrated the feasibility of mapping wind fields in all weather conditions from the clear skies of quiescent air and disturbed prestorm air near the earth's surface to the optically opaque interior of severe and sometimes tornadic thunderstorms. Observations and analyses of Doppler weather radar data demonstrate that improved warning of severe storm phenomena and improved short-term forecast of storms may be available when Doppler techniques are well integrated into the national network of weather radars. When used in combination with other sensors, it provides an opportunity to learn more about the complex interrelations between the wind, water, and electricity in storms.

Doviak, R. J.

1982-01-01

350

Weather Stations: Storms  

NSDL National Science Digital Library

In this activity, learners test how cornstarch and glitter in water move when disturbed. Learners compare their observations with videos of Jupiter's and Earth's storm movements. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

Institute, Lunar A.; Nasa

2011-01-01

351

Weather and the Sky  

NSDL National Science Digital Library

This self-contained module on weather and objects in the sky includes a range of fun activities that students can perform in the classroom and at home with family members. They impart important concepts such as observation, identification, measurement, and differentiation.

Houghton Mifflin Science

352

Synergy of Satellite-Surface Observations for Studying the Properties of Absorbing Aerosols in Asia  

NASA Technical Reports Server (NTRS)

Through interaction with clouds and alteration of the Earth's radiation budget, atmospheric aerosols significantly influence our weather and climate. Monsoon rainfalls, for example, sustain the livelihood of more than half of the world's population. Thus, understanding the mechanism that drives the water cycle and freshwater distribution is high-lighted as one of the major near-term goals in NASA's Earth Science Enterprise Strategy. Every cloud droplet/ice-crystal that serves as an essential element in portraying water cycle and distributing freshwater contains atmospheric aerosols at its core. In addition, the spatial and temporal variability of atmospheric aerosol properties is complex due to their dynamic nature. In fact, the predictability of the tropical climate system is much reduced during the boreal spring, which is associated with the peak season of biomass burning activities and regional/long-range transport of dust aerosols. Therefore, to accurately assess the impact of absorbing aerosols on regional-to-global climate requires not only modeling efforts but also continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. Since 1997 NASA has been successfully launching a series of satellites the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such as the Joint Aerosol Monsoon Experiment (JAM EX), a core element of the Asian Monsoon Years (AMY, 2008-2012). SMART-COMMIT deployments during 2008 AMY/JAMEX were conducted in northwestern China to characterize the properties of dust-laden aerosols and in the vicinity of Beijing for mega-city aerosols. In 2009, SMART-COMMIT also participated in the JAMEX/RAJO-MEGHA (Radiation, Aerosol Joint Observations-Monsoon Experiment in the Gangetic-Himalayan Area; Sanskrit for Dust-Cloud) to study the aerosol properties, solar absorption and the associated atmospheric warming, and the climatic impact of elevated aerosols during the pre-monsoon season in South Asia. We will show results from these field experiments, as well as discuss a new initiative of 7-SEAS (7 South East Asian Studies) to study the interaction of anthropogenic aerosols with regional meteorology, particularly with clouds.

Tsay, Si-Chee

2010-01-01

353

Land-surface controls on afternoon precipitation diagnosed from observational data: uncertainties and confounding factors  

NASA Astrophysics Data System (ADS)

The feedback between soil moisture and precipitation has long been a topic of interest due to its potential for improving weather and seasonal forecasts. The generally proposed mechanism assumes a control of soil moisture on precipitation via the partitioning of the surface turbulent heat fluxes, as assessed via the evaporative fraction (EF), i.e., the ratio of latent heat to the sum of latent and sensible heat, in particular under convective conditions. Our study investigates the poorly understood link between EF and precipitation by relating the before-noon EF to the frequency of afternoon precipitation over the contiguous US, through statistical analyses of multiple EF and precipitation data sets. We analyze remote-sensing data products (Global Land Evaporation: the Amsterdam Methodology (GLEAM) for EF, and radar precipitation from the NEXt generation weather RADar system (NEXRAD)), FLUXNET station data, and the North American Regional Reanalysis (NARR). Data sets agree on a region of positive relationship between EF and precipitation occurrence in the southwestern US. However, a region of strong positive relationship over the eastern US in NARR cannot be confirmed with observation-derived estimates (GLEAM, NEXRAD and FLUXNET). The GLEAM-NEXRAD data set combination indicates a region of positive EF-precipitation relationship in the central US. These disagreements emphasize large uncertainties in the EF data. Further analyses highlight that much of these EF-precipitation relationships could be explained by precipitation persistence alone, and it is unclear whether EF has an additional role in triggering afternoon precipitation. This also highlights the difficulties in isolating a land impact on precipitation. Regional analyses point to contrasting mechanisms over different regions. Over the eastern US, our analyses suggest that the EF-precipitation relationship in NARR is either atmospherically controlled (from precipitation persistence and potential evaporation) or driven by vegetation interception rather than soil moisture. Although this aligns well with the high forest cover and the wet regime of that region, the role of interception evaporation is likely overestimated because of low nighttime evaporation in NARR. Over the central and southwestern US, the EF-precipitation relationship is additionally linked to soil moisture variations, owing to the soil-moisture-limited climate regime.

Guillod, B. P.; Orlowsky, B.; Miralles, D.; Teuling, A. J.; Blanken, P. D.; Buchmann, N.; Ciais, P.; Ek, M.; Findell, K. L.; Gentine, P.; Lintner, B. R.; Scott, R. L.; Van den Hurk, B.; Seneviratne, S. I.

2014-08-01

354

Preliminary observations on responses of embryonic and larval Pacific herring, Clupea pallasi, to neutral fraction biodegradation products of weathered Alaska North Slope oil.  

PubMed

Weathered Alaska North Slope crude oil (ANS 521) was subjected to biodegradation in vigorously stirred incubations for 14 days at 15 +/- 1 degrees C in 20/1000 salinity sterilized seawater, amended with nutrients and inoculated with a hydrocarbon-degrading microorganism (EI2V) isolated from an oil-contaminated beach in Prince William Sound, Alaska. A total of 13.7 mg/L water-soluble neutral fraction (WSF) was recovered from the incubation of weathered ANS 521. Toxicity/ teratogenicity tests were conducted with WSF recovered from the biodegradation system using embryonic and larval Pacific herring, Clupea pallasi. Exposures were begun at 4, 48, and 96 h postfertilization of herring eggs. Exposure concentrations were 1, 10, and 100% of the original concentration of WSF recovered from incubations (redissolved in 20/1000 salinity sterile seawater at 15 +/- 1 degrees C). Sterile 20/1000 salinity seawater without the addition of redissolved neutral fraction was used as a control. Significant (p < or = 0.05) embryo mortality or teratogenic responses were observed at WSF concentrations of 10 and 100%. On days 5 through 8 of embryogenesis, counts of heart contraction rates were significantly lower (p < or = 0.05) at the 100% WSF concentration for embryos exposed beginning at 4 and 48 h postfertilization. Grow-out of larvae from selected exposures was conducted. High mortality was noted in larvae exposed to the 10% WSF concentration beginning at 4 and 48 h postfertilization. Most of these larvae died 5 to 8 days after hatching when they elicited vertebral displacements at a time concurrent with the onset of feeding behavior. PMID:9469861

Middaugh, D P; Shelton, M E; McKenney, C L; Cherr, G; Chapman, P J; Courtney, L A

1998-02-01

355

Large-scale dynamic observation planning for unmanned surface vessels  

E-print Network

With recent advances in research and technology, autonomous surface vessel capabilities have steadily increased. These autonomous surface vessel technologies enable missions and tasks to be performed without the direction ...

Miller, John V. (John Vaala)

2007-01-01

356

Collision and Break-off : Numerical models and surface observables  

NASA Astrophysics Data System (ADS)

The process of continental collision and slab break-off has been explored by many authors using a number of different numerical models and approaches (Andrews and Billen, 2009; Gerya et al., 2004; van Hunen and Allen, 2011). One of the challenges of using numerical models to explore collision and break-off is relating model predictions to real observables from current collision zones. Part of the reason for this is that collision zones by their nature destroy a lot of potentially useful surface evidence of deep dynamics. One observable that offers the possibility for recording mantle dynamics at collision zones is topography. Here we present topography predictions from numerical models and show how these can be related to actual topography changes recoded in the sedimentary record. Both 2D and 3D numerical simulation of the closure of a small oceanic basin are presented (Bottrill et al., 2012; van Hunen and Allen, 2011). Topography is calculated from the normal stress at the surface applied to an elastic beam, to give a more realist prediction of topography by accounting for the expected elasticity of the lithosphere. Predicted model topography showed a number of interesting features on the overriding plate. The first is the formation of a basin post collision at around 300km from the suture. Our models also showed uplift postdating collision between the suture and this basin, caused by subduction of buoyant material. Once break-off has occurred we found that this uplift moved further into the overriding plate due to redistribution of stresses from the subducted plate. With our 3D numerical models we simulate a collision that propagates laterally along a subduction system. These models show that a basin forms, similar to that found in our 2D models, which propagates along the system at the same rate as collision. The apparent link between collision and basin formation leads to the investigation into the stress state in the overriding lithosphere. Preliminary results in this area indicate the stress experienced by the overriding lithosphere changes through the collision and slab break-off process. This change is stress affects the topography, but also offers another observable for understanding collision zones. We relate our numerical model to Arabia-Eurasia collision which is thought to have begun around 35 Ma (Allen and Armstrong, 2008; Vincent et al., 2007). The post collision basin predicted by our numerical model can be associated with the Miocene carbonate deposits of the Qom formation (Morley et al., 2009). These Miocene carbonate deposits are found at approximately 200-300km from the suture zone and are stratigraphically "sandwiched" between terrestrial clastic sedimentary formations. The position of these deposits shows that they are intimately related with the collision process, and that this area of the overriding plate has dipped below sea level for about 10 Myrs during the Early Miocene. Another geographic area that offers possibility for observation of topography change produced during continental collision is the Italian Apennines. Here, slab detachment is proposed to have started around 30 Ma and a tear propagated north to south along Italy (Wortel, 2000). Van der Meulen et al., (1998) observed a period of basin formation followed by uplift using the sedimentary record. Migrating depocentres were interpreted as evidence of a slab tear propagating north to south. These depocentres are located on the overriding plate with the maximum observed depression around 100 km from the suture (Ascione et al., 2012). These observed depocentres could be analogous to the depressions observed in our numerical models. Allen, M. B. and Armstrong, H. A.: Arabia-Eurasia collision and the forcing of mid-Cenozoic global cooling, Palaeogeography, Palaeoclimatology, Palaeoecology, 265(1-2), 52-58, doi:10.1016/j.palaeo.2008.04.021, 2008. Andrews, E. R. and Billen, M. I.: Rheologic controls on the dynamics of slab detachment, Tectonophysics, 464(1-4), 60-69, doi:10.1016/j.tecto.2007.09.004, 2009. Ascione, A., Ciarcia, S.,

Bottrill, Andrew; van Hunen, Jeroen; Allen, Mark

2013-04-01

357

Observation of Surface Vibration Modes by Stroboscopic Hologram Interferometry  

Microsoft Academic Search

Powell and Stetson1 have shown that holography can be used to study the vibration modes of a surface. The technique they employed was to record a hologram while the surface was actually vibrating. The reconstructed image from such a hologram varies in brightness with the total excursion of the surface movement, and gives a kind of ``time-averaged'' contour map of

E. Archbold; A. E. Ennos

1968-01-01

358

Weather Cycles  

NSDL National Science Digital Library

We are professionals in the teaching profession. We designed this project for children ranging from 4th grade to 6th grade. This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. YOU WILL NEED: Paper with copied questions, Overhead projector and Students broken up into groups of 3. Form groups of three. Have each group explore the following simulation: Weather Maker Simulator Have students use the simulation to answer the following questions on paper. They should be discussing the questions in their groups. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What ...

Mitchell, Mrs.

2010-09-23

359

Weather Watchers  

NSDL National Science Digital Library

Students are introduced to some essential meteorology concepts so they more fully understand the impact of meteorological activity on air pollution control and prevention. First, they develop an understanding of the magnitude and importance of air pressure. Next, they build a simple aneroid barometer to understand how air pressure information is related to weather prediction. Then, students explore the concept of relative humidity and its connection to weather prediction. Finally, students learn about air convection currents and temperature inversions. In an associated literacy activity, students learn how scientific terms are formed using Latin and Greek roots, prefixes and suffixes, and are introduced to the role played by metaphor in language development. Note: Some of these activities can be conducted simultaneously with the air quality activity (What Color Is Your Air Today?) of Air Pollution unit, Lesson 1.

Integrated Teaching And Learning Program

360

Observations During GRIP from HIRAD: Images of C-Band Brightness Temperatures and Ocean Surface Wind Speed and Rain Rate  

NASA Technical Reports Server (NTRS)

HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA s GRIP (Genesis and Rapid Intensification Processes) campaign in August - September of 2010. HIRAD is a new C-band radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind speed and rain rate can be inferred. This technique has been used for many years by precursor instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than a single footprint at nadir angle. Results from the flights during the GRIP campaign will be shown, including images of brightness temperatures, wind speed, and rain rate. To the extent possible, comparisons will be made with observations from other instruments on the GRIP campaign, for which HIRAD observations are either directly comparable or are complementary. Features such as storm eye and eyewall, location of vortex wind and rain maxima, and indications of dynamical features such as the merging of a weaker outer wind/rain maximum with the main vortex may be seen in the data. Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts will also be discussed.

Miller, Timothy L.; James, M. W.; Jones, W. L.; Ruf, C. S.; Uhlhorn, E. W.; Biswas, S.; May, C.; Shah, G.; Black, P.; Buckley, C. D.

2012-01-01

361

Great Lakes Weather and Climate Location, Dimensions and Configuration  

NSDL National Science Digital Library

This self-paced, interactive tutorial explores the use of remote-sensing data to monitor Great Lakes weather and climate. Interactive tools are provided to allow the learner to compare the surface area of the different Great Lakes. Seasonal climate extremes observed in the Great Lakes region is explained by the geographical characteristics of its mid-latitudinal location, and are documented in a series of seasonal images produced by satellite sensors. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the first of three modules in the tutorial, Great Lakes Weather and Climate. (Note: requires Java plug-in)

2012-08-03

362

Comparison of interplanetary type 2 radio burst observations by ISEE-3, Ulysses, and WIND with applications to space weather prediction  

NASA Technical Reports Server (NTRS)

Interplanetary (IP) type 2 radio bursts are produced by IP shocks driven by solar ejecta, presumably involving shock acceleration of electrons that leads to radio emission. These radio bursts, which can be detected remotely by a sensitive spacecraft radio receiver, provide a method of tracking the leading edge of solar ejecta moving outward from the sun. Consequently, observations of these bursts sometimes provide advance warning of one or more days prior to the onset of geomagnetic activity induced by the solar ejecta. A robust lower limit on the fraction of intense geomagnetic storms, that are preceded by IP type 2 bursts, is provided. It is shown that 41 percent of the geomagnetic storms occurring during the interval September 1978 to February 1983 were preceded by type 2 events in this catalog, and reasons why the fraction is not larger are addressed. Differences in the observing capabilities of the International Sun-Earth Explorer (ISEE) 3, Ulysses, and WIND, to explain why each of these similar spacecraft radio investigations provides a different perspective of IP type 2 emissions are reviewed.

MacDowall, R. J.; Klimas, A. J.; Lengyel-Frey, D.; Stone, R. G.; Thejappa, G.

1997-01-01

363

Kid Meteorologist - I Love the Weather!  

NSDL National Science Digital Library

What would we do without meteorologists? Weather forecasts enable you to plan everything from what you'll wear to whether weekend activities should be indoors or outdoors. They also help us prepare for bad weather and storms. In this video from the PBS television show ZOOM, a student (Amy from Walpole, MA) describes how her interest in observing the weather led her to volunteer at a local weather center where she uses real weather instruments and learns from a practicing meteorologist how weather forecasts are made.

2005-10-21

364

Aerosol Observability and Predictability: From Research to Operations for Chemical Weather Forecasting. Lagrangian Displacement Ensembles for Aerosol Data Assimilation  

NASA Technical Reports Server (NTRS)

A challenge common to many constituent data assimilation applications is the fact that one observes a much smaller fraction of the phase space that one wishes to estimate. For example, remotely sensed estimates of the column average concentrations are available, while one is faced with the problem of estimating 3D concentrations for initializing a prognostic model. This problem is exacerbated in the case of aerosols because the observable Aerosol Optical Depth (AOD) is not only a column integrated quantity, but it also sums over a large number of species (dust, sea-salt, carbonaceous and sulfate aerosols. An aerosol transport model when driven by high-resolution, state-of-the-art analysis of meteorological fields and realistic emissions can produce skillful forecasts even when no aerosol data is assimilated. The main task of aerosol data assimilation is to address the bias arising from inaccurate emissions, and Lagrangian misplacement of plumes induced by errors in the driving meteorological fields. As long as one decouples the meteorological and aerosol assimilation as we do here, the classic baroclinic growth of error is no longer the main order of business. We will describe an aerosol data assimilation scheme in which the analysis update step is conducted in observation space, using an adaptive maximum-likelihood scheme for estimating background errors in AOD space. This scheme includes e explicit sequential bias estimation as in Dee and da Silva. Unlikely existing aerosol data assimilation schemes we do not obtain analysis increments of the 3D concentrations by scaling the background profiles. Instead we explore the Lagrangian characteristics of the problem for generating local displacement ensembles. These high-resolution state-dependent ensembles are then used to parameterize the background errors and generate 3D aerosol increments. The algorithm has computational complexity running at a resolution of 1/4 degree, globally. We will present the result of assimilating AOD retrievals from MODIS (on both Aqua and TERRA satellites) from AERONET for validation. The impact on the GEOS-5 Aerosol Forecasting will be fully documented.

da Silva, Arlindo

2010-01-01

365

An assessment of buoy-derived and numerical weather prediction surface heat fluxes in the tropical Pacific  

Microsoft Academic Search

As part of the Eastern Pacific Investigation of Climate Processes program, from 2000 through 2003, the easternmost 95°W Tropical Atmosphere Ocean (TAO) moorings were enhanced to provide time series of net surface heat flux, and the National Oceanic and Atmospheric Administration ship maintaining the 95°W and 110°W TAO lines was enhanced to monitor surface heat fluxes and atmospheric boundary layer

Meghan F. Cronin; Christopher W. Fairall; Michael J. McPhaden

2006-01-01

366

Fitting the observed changes of global surface temperatures  

NASA Astrophysics Data System (ADS)

The quality of the fit of a trivial or, conversely, delicately-designed model to the observed natural phenomena is the fundamental pillar stone of any forecasting, including forecasting of the Earth's Climate. Using precise mathematical and logical systems outside their range of applicability can be scientifically groundless, unwise, and even dangerous. The temperature data sets are naturally in the basis of any hypothesizing on variability and forecasting the Earth's Climate. Leaving open the question of the global temperature definitions and their determination (T), we have analyzed hemispheric and global monthly temperature anomaly series produced by the Climate Research Unit of the University of East Anglia (CRUTEM4 database) and more recently by the Berkeley Earth Surface Temperature consortium (BEST database). We first fit the data in 1850-2010 with polynomials of degrees 1 to 9 and compare it with exponential fit by the adjusted R-squared criterion that takes into consideration the number of free parameters of the model. In all the cases considered, the adjusted R-squared values for polynomials are larger than for the exponential as soon as the degree exceeds 1 or 2. The polynomial fits become even more satisfactory as soon as degree 5 or 6 is reached. Extrapolations of these trends outside of the data domain show quick divergence. For example, the CRUTEM4vNH fit in the decade 2010-2020, for degrees 2 to 5, rises steeply then, for degrees 6 to 9, reverses to steep decreasing: the reversal in extrapolated trends arises from improved ability to fit the observed "~60-yr" wave in 150 years of data prior to 2010. The extrapolations prior to 1850 are even more erratic, linked with the increased dispersion of the early data. When focusing the analysis of fits on 1900-2010 we find that the apparent oscillations of T can be modeled by a series of linear segments: An optimal fit suggests 4 slope breaks indicating two clear transitions in 1940 and 1975, and two that are less certain in 1905 and 2005. Interestingly, the Pacific Decadal Oscillation index underwent major changes around 1940-1950 and 1974-1984, i.e. the time of the breaks in slope of the T curve, suggesting a good correlation at the multi-decadal scale between the derivatives of T and PDO index. Therefore, one may speculate that the Earth's climate system may have entered a new multi-decadal regime in the last years of the 20th century and we should expect global temperature to remain constant or decrease slightly while the PDO index remains dominantly negative up to about 2030.

Courtillot, V.; Le Mouël, J.; Kossobokov, V. G.; Gibert, D.; Lopes, F.

2012-12-01

367

Understanding Space Weather: The Sun as a Variable Star  

NASA Technical Reports Server (NTRS)

The Sun is a complex system of systems and until recently, less than half of its surface was observable at any given time and then only from afar. New observational techniques and modeling capabilities are giving us a fresh perspective of the solar interior and how our Sun works as a variable star. This revolution in solar observations and modeling provides us with the exciting prospect of being able to use a vastly increased stream of solar data taken simultaneously from several different vantage points to produce more reliable and prompt space weather forecasts. Solar variations that cause identifiable space weather effects do not happen only on solar-cycle timescales from decades to centuries; there are also many shorter-term events that have their own unique space weather effects and a different set of challenges to understand and predict, such as flares, coronal mass ejections, and solar wind variations

Strong, Keith; Saba, Julia; Kucera, Therese

2011-01-01

368

Use of EOS Data in AWIPS for Weather Forecasting  

NASA Technical Reports Server (NTRS)

Operational weather forecasting relies heavily on real time data and modeling products for forecast preparation and dissemination of significant weather information to the public. The synthesis of this information (observations and model products) by the meteorologist is facilitated by a decision support system to display and integrate the information in a useful fashion. For the NWS this system is called Advanced Weather Interactive Processing System (AWIPS). Over the last few years NASA has launched a series of new Earth Observation Satellites (EOS) for climate monitoring that include several instruments that provide high-resolution measurements of atmospheric and surface features important for weather forecasting and analysis. The key to the utilization of these unique new measurements by the NWS is the real time integration of the EOS data into the AWIPS system. This is currently being done in the Huntsville and Birmingham NWS Forecast Offices under the NASA Short-term Prediction Research and Transition (SPORT) Program. This paper describes the use of near real time MODIS and AIRS data in AWIPS to improve the detection of clouds, moisture variations, atmospheric stability, and thermal signatures that can lead to significant weather development. The paper and the conference presentation will focus on several examples where MODIS and AIRS data have made a positive impact on forecast accuracy. The results of an assessment of the utility of these products for weather forecast improvement made at the Huntsville NWS Forecast Office will be presented.

Jedlovec, Gary J.; Haines, Stephanie L.; Suggs, Ron J.; Bradshaw, Tom; Darden, Chris; Burks, Jason

2003-01-01

369

Land Surface Temperature Forecasting using spectral observations of MODIS and Modular Neural Networks  

NASA Astrophysics Data System (ADS)

Land Surface Temperature (LST) is a significant parameter for many applications including numerical weather prediction, climate and environmental studies. The goal of this study is using a combination of Modular neural networks and satellite image as input to predict the LST in Tehran ,Iran.In this study, two MLP and RBF neural networks and an algorithm for calculating of LST based spectral observations of MODerate resolution Imaging Spectra-radiometer (MODIS) are used This algorithm include Brightness Temperature of channel 31(BT31) and 32(BT32) on thermal band of MODIS. The algorithm are written using Hierarchical Data Format (HDF) calibrated data which has the spatial resolution of 1km by ENVI (Environment for Visualizing Images) software, and output products are in HDF format. Initial results show that modular neural network helps to improve networks' generalization and learning speed and the main reason for selecting these networks is their good performance in this problem.The model has a modular learning and structure. Since the task decomposition at first and the combination of results to get the final prediction at the end are key and effective points on the performance of modular neural network, in this study we propose a new approach to this issue. This method uses the Self-Organizing Map (SOM) Neural Network and Particle Swarm Optimization(PSO) algorithm for task decomposition. The proposed model combines this neural networks and optimization algorithms. Results indicate that use of PSO algorithm has caused suitable distribution of clusters obtained from SOM algorithm. In addition to the use of satellite images has improved the performance of the proposed model. Finally, the results obtained from this model will be compared with some other methods with non-modular structure and learning and it is shown that this proposed model is able to produce accurate results. The result of this comparison show that training time of model in the forecasting of land surface temperature reduces and accuracy of model increase. Key words: Land Surface Temperature, forecasting, satellite images, Modular neural network.

Taghavi, Farahnaz; Zargaran, Zahrah; Ahmadi, Abbas

370

Electrical Properties of the Venus Surface from Bistatic Radar Observations  

NASA Astrophysics Data System (ADS)

A bistatic radar experiment in 1994, involving reception on Earth of a specularly reflected, linearly polarized 13-centimeter-wavelength signal transmitted from the Magellan spacecraft in orbit around Venus, has established that the surface materials viewed at low and intermediate altitudes on Venus have a relative dielectric permittivity of 4.0 ± 0.5. However, bistatic results for the Maxwell Montes highlands imply an electrically lossy surface with an imaginary dielectric permittivity of -i 100 ± 50, probably associated with a specific conductivity of about 13 mhos per meter. Candidates for highlands surface composition include ferroelectrics, a thin frost of elemental tellurium, or a plating of magnetite or pyrites.

Pettengill, Gordon H.; Ford, Peter G.; Simpson, Richard A.

1996-06-01

371

Electrical Properties of the Venus Surface from Bistatic Radar Observations  

PubMed

A bistatic radar experiment in 1994, involving reception on Earth of a specularly reflected, linearly polarized 13-centimeter-wavelength signal transmitted from the Magellan spacecraft in orbit around Venus, has established that the surface materials viewed at low and intermediate altitudes on Venus have a relative dielectric permittivity of 4.0 ± 0.5. However, bistatic results for the Maxwell Montes highlands imply an electrically lossy surface with an imaginary dielectric permittivity of -i 100 ± 50, probably associated with a specific conductivity of about 13 mhos per meter. Candidates for highlands surface composition include ferroelectrics, a thin frost of elemental tellurium, or a plating of magnetite or pyrites. PMID:8662473

Pettengill; Ford; Simpson

1996-06-14

372

AFFILIATIONS: HULTQUIST--NOAA/National Weather Service, Marquette, Michigan; DUTTER--NOAA/National Weather Service,  

E-print Network

likely weather conditions throughout the storm. Meteorological observations from the storm were combined with modern numerical weather prediction models to provide detailed hindcasts of conditions throughout heights because of enhanced vertical transfer of momentum under unstable conditions. Lake Superior

373

Self-assembly of two-dimensional nanoclusters observed with STM: From surface molecules to surface superstructure  

E-print Network

Self-assembly of two-dimensional nanoclusters observed with STM: From surface molecules to surface December 2006 A type of stable and identical two dimensional 2D Au nanoclusters are discovered to exist on the Si 111 - 3 3-Ag surface at submonolayer Au coverage. Self-assembly of these Au nanoclusters leads

Hasegawa, Shuji

374

Smooth Sailing for Weather Forecasting  

NASA Technical Reports Server (NTRS)

Through a cooperative venture with NASA's Stennis Space Center, WorldWinds, Inc., developed a unique weather and wave vector map using space-based radar satellite information and traditional weather observations. Called WorldWinds, the product provides accurate, near real-time, high-resolution weather forecasts. It was developed for commercial and scientific users. In addition to weather forecasting, the product's applications include maritime and terrestrial transportation, aviation operations, precision farming, offshore oil and gas operations, and coastal hazard response support. Target commercial markets include the operational maritime and aviation communities, oil and gas providers, and recreational yachting interests. Science applications include global long-term prediction and climate change, land-cover and land-use change, and natural hazard issues. Commercial airlines have expressed interest in the product, as it can provide forecasts over remote areas. WorldWinds, Inc., is currently providing its product to commercial weather outlets.

2002-01-01

375

Fire-induced changes in surface albedo as observed from MODIS observations  

NASA Astrophysics Data System (ADS)

An integrated assessment of the overall radiative forcing caused by fire is critical for fire and carbon management The forcing due to greenhouse gas is well known but there is a major gap in estimates of forcing due to fire-induced albedo change Our objective is to examine the temporal evolution of post-fire albedo and analyze its relationship with the vegetation succession using MODIS satellite observations We focus on two fire prone regions with very different fire regimes and vegetation succession patterns Australia tropical savanna and Alaska boreal forest We use MODIS albedo and vegetation index data from the years 2000 through 2004 from Northern Australia and interior Alaska Burned area were derived from MODIS observations in Northern Australia and burn perimeters from 1950 through 2003 were identified by using the Alaska Fire History 1950-2004 GIS Database In northern Australia the shortwave albedo decreased by anaverage of 0 024 within 16 to 32 days after fire The albedo decreased by a greater amount in grasslands than woody savannas and as the dry season progressed The albedo starts to increase within months after fire along with ash dissipation and fast vegetation regrowth in savannas In post-fire boreal forest both the vegetation succession and snow cover contributes to the temporal evolution of surface albedo After boreal fire albedo in spring March and April increases by 0 165 as compared with unburned areas and reaches its maximum at nine years since fire In summer June and July albedo shows an initial decrease of

Jin, Y.; Randerson, J.; Roy, D.; Lyons, E.; Goulden, M.

376

Aquarius Observations of Sea Surface Salinity - Duration: 0:31.  

NASA Video Gallery

This visualization shows changes in global sea surface salinity, as measured by NASAâ??s Aquarius instrument aboard the Aquarius/SAC-D spacecraft, from December 2011 through December 2012. Red repr...

377

Surface moisture and satellite microwave observations in semiarid southern Africa  

Microsoft Academic Search

Nimbus 7 scanning multichannel microwave radiometer 6.6-GHz passive microwave data were studied in relation to large-scale soil moisture estimates over a 3-year period in southeastern Bostwana. An extensive data base of weekly surface soil moisture measurements was used with meteorological data to estimate pixel average soil moisture on a daily basis. The influence of the vegetation canopy on the surface

M. Owe; A. T. C. Chang; A. A. Van de Griend

1992-01-01

378

Comparison of Arctic clouds between European Center for Medium-Range Weather Forecasts simulations and Atmospheric Radiation Measurement Climate Research Facility long-term observations at the North Slope of Alaska Barrow site  

NASA Astrophysics Data System (ADS)

This study evaluated the European Center for Medium-Range Weather Forecasts (ECMWF) model-simulated clouds and boundary layer (BL) properties based upon Atmospheric Radiation Measurement Climate Research Facility observations at the North Slope of Alaska site during 1999-2007. The ECMWF model-simulated near-surface humidity had seasonal dependent biases as large as 20%, while also experiencing difficulty representing BL temperature inversion height and strength during the transition seasons. Although the ECMWF model captured the seasonal variation of surface heat fluxes, it had sensible heat flux biases over 20 W m-2 in most of the cold months. Furthermore, even though the model captured the general seasonal variations of low-level cloud fraction (LCF) and liquid water path (LWP), it still overestimated the LCF by 20% or more and underestimated the LWP over 50% in the cold season. On average, the ECMWF model underestimated LWP by ˜30 g m-2 but more accurately predicted ice water path for BL clouds. For BL mixed-phase clouds, the model predicted water-ice mass partition was significantly lower than the observations, largely due to the temperature dependence of water-ice mass partition used in the model. The ECMWF model captured the general response of cloud fraction and LWP on large-scale vertical motion changes but overpredicted the magnitude of the difference, especially for LWP. The new cloud and BL schemes of the ECMWF model that were implemented after 2003 only resulted in minor improvements in BL cloud simulations in summer. These results indicate that significant improvements in cold season BL and mixed-phase cloud processes in the model are needed.

Zhao, Ming; Wang, Zhien

2010-12-01

379

Detection and attribution of extreme weather disasters  

NASA Astrophysics Data System (ADS)

Single disasters related to extreme weather events have caused loss and damage on the order of up to tens of billions US dollars over the past years. Recent disasters fueled the debate about whether and to what extent these events are related to climate change. In international climate negotiations disaster loss and damage is now high on the agenda, and related policy mechanisms have been discussed or are being implemented. In view of funding allocation and effective risk reduction strategies detection and attribution to climate change of extreme weather events and disasters is a key issue. Different avenues have so far been taken to address detection and attribution in this context. Physical climate sciences have developed approaches, among others, where variables that are reasonably sampled over climatically relevant time periods and related to the meteorological characteristics of the extreme event are examined. Trends in these variables (e.g. air or sea surface temperatures) are compared between observations and climate simulations with and without anthropogenic forcing. Generally, progress has been made in recent years in attribution of changes in the chance of some single extreme weather events to anthropogenic climate change but there remain important challenges. A different line of research is primarily concerned with losses related to the extreme weather events over time, using disaster databases. A growing consensus is that the increase in asset values and in exposure are main drivers of the strong increase of economic losses over the past several decades, and only a limited number of studies have found trends consistent with expectations from climate change. Here we propose a better integration of existing lines of research in detection and attribution of extreme weather events and disasters by applying a risk framework. Risk is thereby defined as a function of the probability of occurrence of an extreme weather event, and the associated consequences, with consequences being a function of the intensity of the physical weather event, the exposure and value of assets, and vulnerabilities. We have examined selected major extreme events and disasters, including superstorm Sandy in 2012, the Pakistan floods and the heat wave in Russia in 2010, the 2010 floods in Colombia and the 2011 floods in Australia. We systematically analyzed to what extent (anthropogenic) climate change may have contributed to intensity and frequency of the event, along with changes in the other risk variables, to eventually reach a more comprehensive understanding of the relative role of climate change in recent loss and damage of extreme weather events.

Huggel, Christian; Stone, Dáithí; Hansen, Gerrit

2014-05-01

380

Impact of derived global weather data on simulated crop yields.  

PubMed

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well-maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26-72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA-POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12-19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location-specific observed daily weather databases combined with an appropriate upscaling method. PMID:23801639

van Wart, Justin; Grassini, Patricio; Cassman, Kenneth G

2013-12-01

381

Impact of derived global weather data on simulated crop yields  

PubMed Central

Crop simulation models can be used to estimate impact of current and future climates on crop yields and food security, but require long-term historical daily weather data to obtain robust simulations. In many regions where crops are grown, daily weather data are not available. Alternatively, gridded weather databases (GWD) with complete terrestrial coverage are available, typically derived from: (i) global circulation computer models; (ii) interpolated weather station data; or (iii) remotely sensed surface data from satellites. The present study's objective is to evaluate capacity of GWDs to simulate crop yield potential (Yp) or water-limited yield potential (Yw), which can serve as benchmarks to assess impact of climate change scenarios on crop productivity and land use change. Three GWDs (CRU, NCEP/DOE, and NASA POWER data) were evaluated for their ability to simulate Yp and Yw of rice in China, USA maize, and wheat in Germany. Simulations of Yp and Yw based on recorded daily data from well-maintained weather stations were taken as the control weather data (CWD). Agreement between simulations of Yp or Yw based on CWD and those based on GWD was poor with the latter having strong bias and large root mean square errors (RMSEs) that were 26–72% of absolute mean yield across locations and years. In contrast, simulated Yp or Yw using observed daily weather data from stations in the NOAA database combined with solar radiation from the NASA-POWER database were in much better agreement with Yp and Yw simulated with CWD (i.e. little bias and an RMSE of 12–19% of the absolute mean). We conclude that results from studies that rely on GWD to simulate agricultural productivity in current and future climates are highly uncertain. An alternative approach would impose a climate scenario on location-specific observed daily weather databases combined with an appropriate upscaling method. PMID:23801639

van Wart, Justin; Grassini, Patricio; Cassman, Kenneth G

2013-01-01

382

User's Guide, software for reduction and analysis of daily weather and surface-water data: Tools for time series analysis of precipitation, temperature, and streamflow data  

USGS Publications Warehouse

The software described here is used to process and analyze daily weather and surface-water data. The programs are refinements of earlier versions that include minor corrections and routines to calculate frequencies above a threshold on an annual or seasonal basis. Earlier versions of this software were used successfully to analyze historical precipitation patterns of the Mojave Desert and the southern Colorado Plateau regions, ecosystem response to climate variation, and variation of sediment-runoff frequency related to climate (Hereford and others, 2003; 2004; in press; Griffiths and others, 2006). The main program described here (Day_Cli_Ann_v5.3) uses daily data to develop a time series of various statistics for a user specified accounting period such as a year or season. The statistics include averages and totals, but the emphasis is on the frequency of occurrence in days of relatively rare weather or runoff events. These statistics are indices of climate variation; for a discussion of climate indices, see the Climate Research Unit website of the University of East Anglia (http://www.cru.uea.ac.uk/projects/stardex/) and the Climate Change Indices web site (http://cccma.seos.uvic.ca/ETCCDMI/indices.html). Specifically, the indices computed with this software are the frequency of high intensity 24-hour rainfall, unusually warm temperature, and unusually high runoff. These rare, or extreme events, are those greater than the 90th percentile of precipitation, streamflow, or temperature computed for the period of record of weather or gaging stations. If they cluster in time over several decades, extreme events may produce detectable change in the physical landscape and ecosystem of a given region. Although the software has been tested on a variety of data, as with any software, the user should carefully evaluate the results with their data. The programs were designed for the range of precipitation, temperature, and streamflow measurements expected in the semiarid Southwest United States. The user is encouraged to review the examples provided with the software. The software is written in Fortran 90 with Fortran 95 extensions and was compiled with the Digital Visual Fortran compiler version 6.6. The executables run on Windows 2000 and XP, and they operate in a MS-DOS console window that has only very simple graphical options such as font size and color, background color, and size of the window. Error trapping was not written into the programs. Typically, when an error occurs, the console window closes without a message.

Hereford, Richard

2006-01-01

383

The weathering of oil after the Deepwater Horizon oil spill: insights from the chemical composition of the oil from the sea surface, salt marshes and sediments  

NASA Astrophysics Data System (ADS)

The oil released during the Deepwater Horizon (DWH) oil spill may have both short- and long-time impacts on the northern Gulf of Mexico ecosystems. An understanding of how the composition and concentration of the oil are altered by weathering, including chemical, physical and biological processes, is needed to evaluate the oil toxicity and impact on the ecosystem in the northern Gulf of Mexico. This study examined petroleum hydrocarbons in oil mousse collected from the sea surface and salt marshes, and in oil deposited in sediments adjacent to the wellhead after the DWH oil spill. Oil mousses were collected at two stations (OSS and CT, located 130 and 85 km away from the wellhead, respectively) in May 2010, and two sediment samples from stations SG and SC, within 6 km of the wellhead, in May 2011. We also collected oil mousse from salt marshes at Marsh Point (MP), Mississippi, 186 km away from the wellhead in July 2010. In these samples, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, BTEX (collective name of benzene, toluene, ethylbenzene and p-, m-, and o-xylenes), C3-benzenes and trace metals were measured to examine how the oil was altered chemically. The chemical analysis indicates that the oil mousses underwent different degrees of weathering with the pattern of OSS < CT < MP. This pattern is consistent with the projected oil mousse movement from the accident site to salt marshes. Also, the contents of trace metals Al, V, Cr, Fe, Mn, Ni, Co, Cu, As and Pb in the oil mousse generally increased along the way to the salt marshes, indicating that these trace metals were perhaps aggregated into the oil mousse during the transport. Petroleum hydrocarbon data reveal that the oil deposited in sediments underwent only light to moderate degradation one year after the DWH oil spill, as supported by the presence of short-chained n-alkanes (C10-C 15), BTEX and C 3-benzenes. The weathering of oil in sediment may result from biological degradation and dissolution, evidenced by the preferential loss of mid-chained n-alkanes C16-C 27, lower ratios of n-C 17/Pr and n-C 18/Ph , and preferential loss of PAHs relative to alkylated PAHs.

Liu, Zhanfei; Liu, Jiqing; Zhu, Qingzhi; Wu, Wei

2012-09-01

384

Observations of quenching of downward-facing surfaces  

SciTech Connect

This report documents results of a series of scoping experiments on boiling from downward-facing surfaces in support of the Sandia New Production Reactor, Vessel-Pool Boiling Heat Transfer task. Quenching experiments have been performed to examine the boiling processes from downward-facing surfaces using two 61-centimeter diameter test masses, one with a flat test surface and one with a curved test surface having a radius of curvature of 335 cm, matching that of the Cylindrical Boiling facility test vessel. Boiling curves were obtained for both test surfaces facing horizontally downward. The critical beat flux was found to be essentially the same, having an average value of approximately 0.5 MW/m{sup 2}. This value is substantially higher than current estimates of the heat dissipation rates required for in-vessel retention of core debris in the Heavy Water New Production Reactor as well as some of the advanced light water reactors under design. The nucleate boiling process was found to be cyclic with four relatively distinct phases: direct liquid/solid contact, nucleation and growth of bubbles, coalescence, and ejection.

Chu, T.Y.; Bainbridge, B.L.; Bentz, J.H.; Simpson, R.B.

1994-01-01

385

Why are climate models reproducing the observed global surface warming so well?  

E-print Network

Why are climate models reproducing the observed global surface warming so well? Reto Knutti1 global surface warming so well?, Geophys. Res. Lett., 35, L18704, doi:10.1029/ 2008GL034932. 1 models reproduce the observed surface warming better than one would expect given the uncertainties

Fischlin, Andreas

386

Nucleation at the Contact Line Observed on Nanotextured Surfaces  

NASA Astrophysics Data System (ADS)

It has been conjectured that roughness plays a role in surface nucleation, the tendency for freezing to begin preferentially at the liquid-gas interface. Using high speed imaging, we sought evidence for freezing at the contact line on catalyst substrates with imposed characteristic length scales (texture). Length scales consistent with the critical nucleus size and with ? ˜? /? , where ? is a relevant line tension and ? is the surface tension, range from nanometers to micrometers. It is found that nanoscale texture causes a shift in the nucleation of ice in supercooled water to the three-phase contact line, while microscale texture does not.

Gurganus, C. W.; Charnawskas, J. C.; Kostinski, A. B.; Shaw, R. A.

2014-12-01

387

Nucleation at the contact line observed on nanotextured surfaces.  

PubMed

It has been conjectured that roughness plays a role in surface nucleation, the tendency for freezing to begin preferentially at the liquid-gas interface. Using high speed imaging, we sought evidence for freezing at the contact line on catalyst substrates with imposed characteristic length scales (texture). Length scales consistent with the critical nucleus size and with ???/?, where ? is a relevant line tension and ? is the surface tension, range from nanometers to micrometers. It is found that nanoscale texture causes a shift in the nucleation of ice in supercooled water to the three-phase contact line, while microscale texture does not. PMID:25526136

Gurganus, C W; Charnawskas, J C; Kostinski, A B; Shaw, R A

2014-12-01

388

The Weather Dude  

NSDL National Science Digital Library

The Weather Dude is a weather education Web site offered by meteorologist Nick Walker of The Weather Channel. For kids, the site offers a great online textbook entitled Weather Basics, which explains everything from precipitation to the seasons, using simple text and fun graphics. Other fun things for kids include weather songs, questions and quizzes, weather proverbs, and more. Teachers are also provided with helpful resources such as weather activity sheets and printable blank maps, as well as many other links to weather forecasts and information that will help make teaching about weather fun.

Walker, Nick.

2002-01-01

389

Vertical transport of surface fire emissions observed Siegfried Gonzi1  

E-print Network

estimation to infer the vertical distribution of surface emissions lofted from boreal and tropical biomass of information. We use a maximum a posteriori (MAP) methodology to estimate emitted CO mass in five vertical, of which 672 are colocated with MLS. We define an injection height based on MAP statistics. We find that 10

Palmer, Paul

390

Asteroid surface mineralogy: Evidence from earth-based telescope observations  

NASA Technical Reports Server (NTRS)

The interpretation of asteroid reflectance spectrophotometry in terms of mineralogical types gives inferred mineral assemblages for about 60 asteroids. Asteroid surface materials are compared with similar materials that make up many meteorites. The absence of asteroids with spectra that match identically the ordinary chondrites is noted.

Mccord, T. B.

1978-01-01

391

Seasonal and Interannual Variations of Ice Sheet Surface Elevation at the Summit of Greenland: Observed and Modeled  

NASA Technical Reports Server (NTRS)

Observed seasonal and interannual variations in the surface elevation over the summit of the Greenland ice sheet are modeled using a new temperature-dependent formulation of firn-densification and observed accumulation variations. The observed elevation variations are derived from ERS (European Remote Sensing)-1 and ERS-2 radar altimeter data for the period between April 1992 and April 1999. A multivariate linear/sine function is fitted to an elevation time series constructed from elevation differences measured by radar altimetry at orbital crossovers. The amplitude of the seasonal elevation cycle is 0.25 m peak-to-peak, with a maximum in winter and a minimum in summer. Inter-annually, the elevation decreases to a minimum in 1995, followed by an increase to 1999, with an overall average increase of 4.2 cm a(exp -1) for 1992 to 1999. Our densification formulation uses an initial field-density profile, the AWS (automatic weather station) surface temperature record, and a temperature-dependent constitutive relation for the densification that is based on laboratory measurements of crystal growth rates. The rate constant and the activation energy commonly used in the Arrhenius-type constitutive relation for firn densification are also temperature dependent, giving a stronger temperature and seasonal amplitudes about 10 times greater than previous densification formulations. Summer temperatures are most important, because of the strong non-linear dependence on temperature. Much of firn densification and consequent surface lowering occurs within about three months of the summer season, followed by a surface build-up from snow accumulation until spring. Modeled interannual changes of the surface elevation, using the AWS measurements of surface temperature and accumulation and results of atmospheric modeling of precipitation variations, are in good agreement with the altimeter observations. In the model, the surface elevation decreases about 20 cm over the seven years due to more compaction driven by increasing summer temperatures. The minimum elevation in 1995 is driven mainly by a temporary accumulation decrease and secondarily by warmer temperatures. However, the overall elevation increase over the seven years is dominated by the accumulation increase in the later years.

Zwally, H. Jay; Jun, Li; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

392

Stormy weather in galaxy clusters  

PubMed

Recent x-ray, optical, and radio observations coupled with particle and gas dynamics numerical simulations reveal an unexpectedly complex environment within clusters of galaxies, driven by ongoing accretion of matter from large-scale supercluster filaments. Mergers between clusters and continuous infall of dark matter and baryons from the cluster periphery produce long-lived "stormy weather" within the gaseous cluster atmosphere-shocks, turbulence, and winds of more than 1000 kilometers per second. This weather may be responsible for shaping a rich variety of extended radio sources, which in turn act as "barometers" and "anemometers" of cluster weather. PMID:9545210

Burns

1998-04-17

393

Goddard Laboratory for Atmospheric Sciences physical retrieval system for remote determination of weather and climate parameter from HIRS2 and MSU observations  

NASA Technical Reports Server (NTRS)

At the Goddard Laboratory for Atmospheric Sciences (GLAS) a physically based satellite temperature sounding retrieval system, involving the simultaneous analysis of HIRS2 and MSU sounding data, was developed for determining atmospheric and surface conditions which are consistent with the observed radiances. In addition to determining accurate atmospheric temperature profiles even in the presence of cloud contamination, the system provides global estimates of day and night sea or land surface temperatures, snow and ice cover, and parameters related to cloud cover. Details of the system are described elsewhere. A brief overview of the system is presented, as well as recent improvements and previously unpublished results, relating to the sea-surface intercomparison workshop, the diurnal variation of ground temperatures, and forecast impact tests.

Susskind, J.

1984-01-01