15 CFR 200.107 - WWV-WWVH-WWVB broadcasts.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., and 20, MHz (WWV) and 2.5, 5, 10, and 15 MHz (WWVH); (2) standard time signals; (3) time intervals; (4...) Omega Navigation System status reports; (9) geophysical alerts; and (10) marine storm warnings. NIST... correction is “plus” 0.3 second. If the ninth, 10th, 11th, and 12th ticks are doubled, the correction is...

15 CFR 200.107 - WWV-WWVH-WWVB broadcasts.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., and 20, MHz (WWV) and 2.5, 5, 10, and 15 MHz (WWVH); (2) standard time signals; (3) time intervals; (4...) Omega Navigation System status reports; (9) geophysical alerts; and (10) marine storm warnings. NIST... correction is “plus” 0.3 second. If the ninth, 10th, 11th, and 12th ticks are doubled, the correction is...

78 FR 22411 - List of Approved Spent Fuel Storage Casks: HI-STORM 100, Amendment No. 8; Corrections

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-16

... Fuel Storage Casks: HI-STORM 100, Amendment No. 8; Corrections AGENCY: Nuclear Regulatory Commission... revising the Holtec International, Inc. (Holtec) HI-STORM 100 Cask System listing within the ``List of... the Holtec HI-STORM 100 Cask System, Amendment No. 8. The purpose of this document is to provide...

Ratios of total suspended solids to suspended sediment concentrations by particle size

USGS Publications Warehouse

Selbig, W.R.; Bannerman, R.T.

2011-01-01

Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

glopara files

Science.gov Websites

prepbufr BUFR biascr.$CDUMP.$CDATE Time dependent sat bias correction file abias text satang.$CDUMP.$CDATE Angle dependent sat bias correction satang text sfcanl.$CDUMP.$CDATE surface analysis sfcanl binary tcvitl.$CDUMP.$CDATE Tropical Storm Vitals syndata.tcvitals.tm00 text adpsfc.$CDUMP.$CDATE Surface land

Monitoring Inland Storm Surge and Flooding from Hurricane Rita

USGS Publications Warehouse

McGee, Benton D.; Tollett, Roland W.; Mason, Jr., Robert R.

2006-01-01

Pressure transducers (sensors) and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network of sensors was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations, and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast.

Ion radial diffusion in an electrostatic impulse model for stormtime ring current formation

NASA Technical Reports Server (NTRS)

Chen, Margaret W.; Schulz, Michael; Lyons, Larry R.; Gorney, David J.

1992-01-01

Guiding-center simulations of stormtime transport of ring-current and radiation-belt ions having first adiabatic invariants mu is approximately greater than 15 MeV/G (E is approximately greater than 165 keV at L is approximately 3) are surprisingly well described (typically within a factor of approximately less than 4) by the quasilinear theory of radial diffusion. This holds even for the case of an individual model storm characterized by substorm-associated impulses in the convection electric field, provided that the actual spectrum of the electric field is incorporated in the quasilinear theory. Correction of the quasilinear diffusion coefficient D(sub LL)(sup ql) for drift-resonance broadening (so as to define D(sub LL)(sup ql)) reduced the typical discrepancy with the diffusion coefficients D(sub LL)(sup sim) deduced from guiding-center simulations of representative-particle trajectories to a factor of approximately 3. The typical discrepancy was reduced to a factor of approximately 1.4 by averaging D(sub LL)(sup sim), D(sub LL)(sup ql), and D(sub LL)(sup rb) over an ensemble of model storms characterized by different (but statistically equivalent) sets of substorm-onset times.

Analysis of Best Management Practices for Storm Water Compliance at Air Force Airfields

DTIC Science & Technology

1993-09-01

before selecting an infiltration system. These factors include the local vegetation, soil type and condition, groundwater condition, and storm water quality . The...reduce the peak flow rate of storm water discharges and remove sediments in order to improve storm water quality . Detention facilities should be...discharge rate of runoff and/or provide significant detention time to improve storm water quality through natural physical, chemical, and biological

Application of flood-intensity-duration curve, rainfall-intensity-duration curve and time of concentration to analyze the pattern of storms and their corresponding floods for the natural flood events

NASA Astrophysics Data System (ADS)

Kim, Nam Won; Shin, Mun-Ju; Lee, Jeong Eun

2016-04-01

The analysis of storm effects on floods is essential step for designing hydraulic structure and flood plain. There are previous studies for analyzing the relationship between the storm patterns and peak flow, flood volume and durations for various sizes of the catchments, but they are not enough to analyze the natural storm effects on flood responses quantitatively. This study suggests a novel method of quantitative analysis using unique factors extracted from the time series of storms and floods to investigate the relationship between natural storms and their corresponding flood responses. We used a distributed rainfall-runoff model of Grid based Rainfall-runoff Model (GRM) to generate the simulated flow and areal rainfall for 50 catchments in Republic of Korea size from 5.6 km2 to 1584.2 km2, which are including overlapped dependent catchments and non-overlapped independent catchments. The parameters of the GRM model were calibrated to get the good model performances of Nash-Sutcliffe efficiency. Then Flood-Intensity-Duration Curve (FIDC) and Rainfall-Intensity-Duration Curve (RIDC) were generated by Flood-Duration-Frequency and Intensity-Duration-Frequency methods respectively using the time series of hydrographs and hyetographs. Time of concentration developed for the Korea catchments was used as a consistent measure to extract the unique factors from the FIDC and RIDC over the different size of catchments. These unique factors for the storms and floods were analyzed against the different size of catchments to investigate the natural storm effects on floods. This method can be easily used to get the intuition of the natural storm effects with various patterns on flood responses. Acknowledgement This research was supported by a grant (11-TI-C06) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

Two-step forecast of geomagnetic storm using coronal mass ejection and solar wind condition

PubMed Central

Kim, R-S; Moon, Y-J; Gopalswamy, N; Park, Y-D; Kim, Y-H

2014-01-01

To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (Bz ≤ −5 nT or Ey ≥ 3 mV/m for t≥ 2 h for moderate storms with minimum Dst less than −50 nT) and a Dst model developed by Temerin and Li (2002, 2006) (TL model). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90%) than the forecasts based on the TL model (87%). However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80%) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (∩), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81%) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (∪), all geomagnetic storms are correctly forecasted. PMID:26213515

Two-step forecast of geomagnetic storm using coronal mass ejection and solar wind condition.

PubMed

Kim, R-S; Moon, Y-J; Gopalswamy, N; Park, Y-D; Kim, Y-H

2014-04-01

To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study ( B z  ≤ -5 nT or E y  ≥ 3 mV/m for t ≥ 2 h for moderate storms with minimum Dst less than -50 nT) and a Dst model developed by Temerin and Li (2002, 2006) (TL model). Using 55 CME- Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90%) than the forecasts based on the TL model (87%). However, the latter produces better forecasts for 24 nonstorm events (88%), while the former correctly forecasts only 71% of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80%) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (∩), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81%) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (∪), all geomagnetic storms are correctly forecasted.

Predicting geomorphic evolution through integration of numerical-model scenarios and topographic/bathymetric-survey updates

NASA Astrophysics Data System (ADS)

Plant, N. G.; Long, J.; Dalyander, S.; Thompson, D.; Miselis, J. L.

2013-12-01

Natural resource and hazard management of barrier islands requires an understanding of geomorphic changes associated with long-term processes and storms. Uncertainty exists in understanding how long-term processes interact with the geomorphic changes caused by storms and the resulting perturbations of the long-term evolution trajectories. We use high-resolution data sets to initialize and correct high-fidelity numerical simulations of oceanographic forcing and resulting barrier island evolution. We simulate two years of observed storms to determine the individual and cumulative impacts of these events. Results are separated into cross-shore and alongshore components of sediment transport and compared with observed topographic and bathymetric changes during these time periods. The discrete island change induced by these storms is integrated with previous knowledge of long-term net alongshore sediment transport to project island evolution. The approach has been developed and tested using data collected at the Chandeleur Island chain off the coast of Louisiana (USA). The simulation time period included impacts from tropical and winter storms, as well as a human-induced perturbation associated with construction of a sand berm along the island shoreline. The predictions and observations indicated that storm and long-term processes both contribute to the migration, lowering, and disintegration of the artificial berm and natural island. Further analysis will determine the relative importance of cross-shore and alongshore sediment transport processes and the dominant time scales that drive each of these processes and subsequent island morphologic response.

Polar cap potential saturation during the Bastille Day storm event using global MHD simulation

NASA Astrophysics Data System (ADS)

Kubota, Y.; Nagatsuma, T.; Den, M.; Tanaka, T.; Fujita, S.

2017-04-01

We investigated the temporal variations and saturation of the cross polar cap potential (CPCP) in the Bastille Day storm event (15 July 2000) by global magnetohydrodynamics (MHD) simulation. The CPCP is considered to depend on the electric field and dynamic pressure of the solar wind as well as on the ionospheric conductivity. Previous studies considered only the ionospheric conductivity due to solar extreme ultraviolet (EUV) variations. In this paper, we dealt with the changes in the CPCP attributable to auroral conductivity variations caused by pressure enhancement in the inner magnetosphere owing to energy injection from the magnetosphere because the energy injection is considerably enhanced in a severe magnetic storm event. Our simulation reveals that the auroral conductivity enhancement is significant for the CPCP variation in a severe magnetic storm event. The numerical results concerning the Bastille Day event show that the ionospheric conductivity averaged over the auroral oval is enhanced up to 18 mho in the case of Bz of less than -59 nT. On the other hand, the average conductivity without the auroral effect is almost 6 mho throughout the entire period. Resultantly, the saturated CPCP is about 240 kV in the former and 704 kV in the latter when Bz is -59 nT. This result indicates that the CPCP variations could be correctly reproduced when the time variation of auroral conductivity caused by pressure enhancement due to the energy injection from the magnetosphere is correctly considered in a severe magnetic storm event.

Lorentz-Shaped Comet Dust Trail Cross Section from New Hybrid Visual and Video Meteor Counting Technique - Implications for Future Leonid Storm Encounters

NASA Technical Reports Server (NTRS)

Jenniskens, Peter; Crawford, Chris; Butow, Steven J.; Nugent, David; Koop, Mike; Holman, David; Houston, Jane; Jobse, Klaas; Kronk, Gary

2000-01-01

A new hybrid technique of visual and video meteor observations was developed to provide high precision near real-time flux measurements for satellite operators from airborne platforms. A total of 33,000 Leonids. recorded on video during the 1999 Leonid storm, were watched by a team of visual observers using a video head display and an automatic counting tool. The counts reveal that the activity profile of the Leonid storm is a Lorentz profile. By assuming a radial profile for the dust trail that is also a Lorentzian, we make predictions for future encounters. If that assumption is correct, we passed 0.0003 AU deeper into the 1899 trailet than expected during the storm of 1999 and future encounters with the 1866 trailet will be less intense than. predicted elsewhere.

From mess to mass: a methodology for calculating storm event pollutant loads with their uncertainties, from continuous raw data time series.

PubMed

Métadier, M; Bertrand-Krajewski, J-L

2011-01-01

With the increasing implementation of continuous monitoring of both discharge and water quality in sewer systems, large data bases are now available. In order to manage large amounts of data and calculate various variables and indicators of interest it is necessary to apply automated methods for data processing. This paper deals with the processing of short time step turbidity time series to estimate TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) event loads in sewer systems during storm events and their associated uncertainties. The following steps are described: (i) sensor calibration, (ii) estimation of data uncertainties, (iii) correction of raw data, (iv) data pre-validation tests, (v) final validation, and (vi) calculation of TSS and COD event loads and estimation of their uncertainties. These steps have been implemented in an integrated software tool. Examples of results are given for a set of 33 storm events monitored in a stormwater separate sewer system.

Correction to "Energy Transport in the Thermosphere During the Solar Storms of April 2002"

NASA Technical Reports Server (NTRS)

Mlynczak, Martin G.; Martin-Torres, F. Javier; Russell, James M., III

2007-01-01

We present corrected computations of the infrared power and energy radiated by nitric oxide (NO) and carbon dioxide (CO2) during the solar storm event of April 2002. The computations in our previous paper underestimated the radiated power due to improper weighting of the radiated power and energy with respect to area as a function of latitude. We now find that the radiation by NO during the April 2002 storm period accounts for 50% of the estimated energy input to the atmosphere from the solar storm. The prior estimate was 28.5%. Emission computed for CO2 is also correspondingly increased, but the relative roles of CO2 and NO remain unchanged. NO emission enhancement is still, far and away, the dominant infrared response to the solar storms of April 2002.

High resolution field monitoring in coastal wetlands of the U.S. Mid-Atlantic to support quantification of storm surge attenuation at the regional scale

NASA Astrophysics Data System (ADS)

Paquier, A. E.; Haddad, J.; Lawler, S.; Garzon Hervas, J. L.; Ferreira, C.

2015-12-01

Hurricane Sandy (2012) demonstrated the vulnerability of the US East Coast to extreme events, and motivated the exploration of resilient coastal defenses that incorporate both hard engineering and natural strategies such as the restoration, creation and enhancement of coastal wetlands and marshes. Past laboratory and numerical studies have indicated the potential of wetlands to attenuate storm surge, and have demonstrated the complexity of the surge hydrodynamic interactions with wetlands. Many factors control the propagation of surge in these natural systems including storm characteristics, storm-induced hydrodynamics, landscape complexity, vegetation biomechanical properties and the interactions of these different factors. While previous field studies have largely focused on the impact of vegetation characteristics on attenuation processes, few have been undertaken with holistic consideration of these factors and their interactions. To bridge this gap of in-situ field data and to support the calibration of storm surge and wave numerical models such that wetlands can be correctly parametrized on a regional scale, we are carrying out high resolution surveys of hydrodynamics (pressure, current intensity and direction), morphology (topo-bathymetry, micro-topography) and vegetation (e.g. stem density, height, vegetation frontal area) in 4 marshes along the Chesapeake Bay. These areas are representative of the ecosystems and morphodynamic functions present in this region, from the tidal Potomac marshes to the barrier-island back-bays of the Delmarva Peninsula. The field monitoring program supports the investigation of the influence of different types of vegetation on water level, swell and wind wave attenuation and morphological evolution during storm surges. This dataset is also used to calibrate and validate numerical simulations of hurricane storm surge propagation at regional and local scales and to support extreme weather coastal resilience planning in the region. Figure 1 shows an area prone to storm surge impact within one of the 4 study sites: the Dameron Marsh Natural Area Preserve, located on the shoreline of the Northern Peninsula of Virginia, along the Chesapeake Bay.

Improvement of Storm Forecasts Using Gridded Bayesian Linear Regression for Northeast United States

NASA Astrophysics Data System (ADS)

Yang, J.; Astitha, M.; Schwartz, C. S.

2017-12-01

Bayesian linear regression (BLR) is a post-processing technique in which regression coefficients are derived and used to correct raw forecasts based on pairs of observation-model values. This study presents the development and application of a gridded Bayesian linear regression (GBLR) as a new post-processing technique to improve numerical weather prediction (NWP) of rain and wind storm forecasts over northeast United States. Ten controlled variables produced from ten ensemble members of the National Center for Atmospheric Research (NCAR) real-time prediction system are used for a GBLR model. In the GBLR framework, leave-one-storm-out cross-validation is utilized to study the performances of the post-processing technique in a database composed of 92 storms. To estimate the regression coefficients of the GBLR, optimization procedures that minimize the systematic and random error of predicted atmospheric variables (wind speed, precipitation, etc.) are implemented for the modeled-observed pairs of training storms. The regression coefficients calculated for meteorological stations of the National Weather Service are interpolated back to the model domain. An analysis of forecast improvements based on error reductions during the storms will demonstrate the value of GBLR approach. This presentation will also illustrate how the variances are optimized for the training partition in GBLR and discuss the verification strategy for grid points where no observations are available. The new post-processing technique is successful in improving wind speed and precipitation storm forecasts using past event-based data and has the potential to be implemented in real-time.

On the derivation of the areal reduction factor of storms

NASA Astrophysics Data System (ADS)

Bacchi, Baldassare; Ranzi, Roberto

A stochastic derivation of the areal reduction factor (ARF) of the storm intensity is presented: it is based on the analysis of the crossing properties of the rainfall process aggregated in space and time. As a working hypothesis, the number of crossings of high rainfall intensity levels is assumed to be Poisson-distributed and a hyperbolic tail of the probability of exceedances of rainfall intensity has been adopted. These hypotheses are supported by the analysis of radar maps during an intense storm event which occurred in Northern Italy. The reduction factor derived from this analysis shows a power-law decay with respect to the area of integration and the duration of the storm. The areal reduction results as a function of the storm duration and of its frequency. A weak, but significant decrease of the areal reduction factor with respect to the return period is shown by the functions derived, and this result is consistent with that of some recent studies on this topic. The results derived, although preliminary, may find useful applications for the definition of the design storm in urban catchments of a size greater than some square kilometres and with duration of some hours.

Sediment movement along the U.S. east coast continental shelf-I. Estimates of bottom stress using the Grant-Madsen model and near-bottom wave and current measurements

USGS Publications Warehouse

Lyne, V.D.; Butman, B.; Grant, W.D.

1990-01-01

Bottom stress is calculated for several long-term time-series observations, made on the U.S. east coast continental shelf during winter, using the wave-current interaction and moveable bed models of Grant and Madsen (1979, Journal of Geophysical Research, 84, 1797-1808; 1982, Journal of Geophysical Research, 87, 469-482). The wave and current measurements were obtained by means of a bottom tripod system which measured current using a Savonius rotor and vane and waves by means of a pressure sensor. The variables were burst sampled about 10% of the time. Wave energy was reasonably resolved, although aliased by wave groupiness, and wave period was accurate to 1-2 s during large storms. Errors in current speed and direction depend on the speed of the mean current relative to the wave current. In general, errors in bottom stress caused by uncertainties in measured current speed and wave characteristics were 10-20%. During storms, the bottom stress calculated using the Grant-Madsen models exceeded stress computed from conventional drag laws by a factor of about 1.5 on average and 3 or more during storm peaks. Thus, even in water as deep as 80 m, oscillatory near-bottom currents associated with surface gravity waves of period 12 s or longer will contribute substantially to bottom stress. Given that the Grant-Madsen model is correct, parameterizations of bottom stress that do not incorporate wave effects will substantially underestimate stress and sediment transport in this region of the continental shelf.

Storm time global thermosphere: A driven-dissipative thermodynamic system

NASA Astrophysics Data System (ADS)

Burke, W. J.; Lin, C. S.; Hagan, M. P.; Huang, C. Y.; Weimer, D. R.; Wise, J. O.; Gentile, L. C.; Marcos, F. A.

2009-06-01

Orbit-averaged mass densities $\\overline{\\rho and exospheric temperatures $\\overline{T ∞ inferred from measurements by accelerometers on the Gravity Recovery and Climate Experiment (GRACE) satellites are used to investigate global energy Eth and power Πth inputs to the thermosphere during two complex magnetic storms. Measurements show $\\overline{\\rho, $\\overline{T ∞, and Eth rising from and returning to prevailing baselines as the magnetospheric electric field $\\varepsilon$ VS and the Dst index wax and wane. Observed responses of Eth and $\\overline{T ∞ to $\\varepsilon$ VS driving suggest that the storm time thermosphere evolves as a driven-but-dissipative thermodynamic system, described by a first-order differential equation that is identical in form to that governing the behavior of Dst. Coupling and relaxation coefficients of the Eth, $\\overline{T ∞, and Dst equations are established empirically. Numerical solutions of the equations for $\\overline{T ∞ and Eth are shown to agree with GRACE data during large magnetic storms. Since $\\overline{T ∞ and Dst have the same $\\varepsilon$ VS driver, it is possible to combine their governing equations to obtain estimates of storm time thermospheric parameters, even when lacking information about interplanetary conditions. This approach has the potential for significantly improving the performance of operational models used to calculate trajectories of satellites and space debris and is also useful for developing forensic reconstructions of past magnetic storms. The essential correctness of the approach is supported by agreement between thermospheric power inputs calculated from both GRACE-based estimates of Eth and the Weimer Poynting flux model originally derived from electric and magnetic field measurements acquired by the Dynamics Explorer 2 satellite.

A downscaling method for the assessment of local climate change

NASA Astrophysics Data System (ADS)

Bruno, E.; Portoghese, I.; Vurro, M.

2009-04-01

The use of complimentary models is necessary to study the impact of climate change scenarios on the hydrological response at different space-time scales. However, the structure of GCMs is such that their space resolution (hundreds of kilometres) is too coarse and not adequate to describe the variability of extreme events at basin scale (Burlando and Rosso, 2002). To bridge the space-time gap between the climate scenarios and the usual scale of the inputs for hydrological prediction models is a fundamental requisite for the evaluation of climate change impacts on water resources. Since models operate a simplification of a complex reality, their results cannot be expected to fit with climate observations. Identifying local climate scenarios for impact analysis implies the definition of more detailed local scenario by downscaling GCMs or RCMs results. Among the output correction methods we consider the statistical approach by Déqué (2007) reported as a ‘Variable correction method' in which the correction of model outputs is obtained by a function build with the observation dataset and operating a quantile-quantile transformation (Q-Q transform). However, in the case of daily precipitation fields the Q-Q transform is not able to correct the temporal property of the model output concerning the dry-wet lacunarity process. An alternative correction method is proposed based on a stochastic description of the arrival-duration-intensity processes in coherence with the Poissonian Rectangular Pulse scheme (PRP) (Eagleson, 1972). In this proposed approach, the Q-Q transform is applied to the PRP variables derived from the daily rainfall datasets. Consequently the corrected PRP parameters are used for the synthetic generation of statistically homogeneous rainfall time series that mimic the persistency of daily observations for the reference period. Then the PRP parameters are forced through the GCM scenarios to generate local scale rainfall records for the 21st century. The statistical parameters characterizing daily storm occurrence, storm intensity and duration needed to apply the PRP scheme are considered among STARDEX collection of extreme indices.

Predicting severe winter coastal storm damage

NASA Astrophysics Data System (ADS)

Hondula, David M.; Dolan, Robert

2010-07-01

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'—such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989—are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the losses along the North Carolina coast would rank amongst the all-time most costly natural disasters to have occurred in the United States, with up to 1 billion in losses in North Carolina alone.

Effects of the H-3 Highway Stormwater Runoff on the Water Quality of Halawa Stream, Oahu, Hawaii, November 1998 to August 2004

USGS Publications Warehouse

Wolff, Reuben H.; Wong, Michael F.

2008-01-01

Since November 1998, water-quality data have been collected from the H-3 Highway Storm Drain C, which collects runoff from a 4-mi-long viaduct, and from Halawa Stream on Oahu, Hawaii. From January 2001 to August 2004, data were collected from the storm drain and four stream sites in the Halawa Stream drainage basin as part of the State of Hawaii Department of Transportation Storm Water Monitoring Program. Data from the stormwater monitoring program have been published in annual reports. This report uses these water-quality data to explore how the highway storm-drain runoff affects Halawa Stream and the factors that might be controlling the water quality in the drainage basin. In general, concentrations of nutrients, total dissolved solids, and total suspended solids were lower in highway runoff from Storm Drain C than at stream sites upstream and downstream of Storm Drain C. The opposite trend was observed for most trace metals, which generally occurred in higher concentrations in the highway runoff from Storm Drain C than in the samples collected from Halawa Stream. The absolute contribution from Storm Drain C highway runoff, in terms of total storm loads, was much smaller than at stations upstream and downstream, whereas the constituent yields (the relative contribution per unit drainage basin area) at Storm Drain C were comparable to or higher than storm yields at stations upstream and downstream. Most constituent concentrations and loads in stormwater runoff increased in a downstream direction. The timing of the storm sampling is an important factor controlling constituent concentrations observed in stormwater runoff samples. Automated point samplers were used to collect grab samples during the period of increasing discharge of the storm throughout the stormflow peak and during the period of decreasing discharge of the storm, whereas manually collected grab samples were generally collected during the later stages near the end of the storm. Grab samples were analyzed to determine concentrations and loads at a particular point in time. Flow-weighted time composite samples from the automated point samplers were analyzed to determine mean constituent concentrations or loads during a storm. Chemical analysis of individual grab samples from the automated point sampler at Storm Drain C demonstrated the ?first flush? phenomenon?higher constituent concentrations at the beginning of runoff events?for the trace metals cadmium, lead, zinc, and copper, whose concentrations were initially high during the period of increasing discharge and gradually decreased over the duration of the storm. Water-quality data from Storm Drain C and four stream sites were compared to the State of Hawaii Department of Health (HDOH) water-quality standards to determine the effects of highway storm runoff on the water quality of Halawa Stream. The geometric-mean standards and the 10- and 2-percent-of-the-time concentration standards for total nitrogen, nitrite plus nitrate, total phosphorus, total suspended solids, and turbidity were exceeded in many of the comparisons. However, these standards were not designed for stormwater sampling, in which constituent concentrations would be expected to increase for short periods of time. With the aim of enhancing the usefulness of the water-quality data, several modifications to the stormwater monitoring program are suggested. These suggestions include (1) the periodic analyzing of discrete samples from the automated point samplers over the course of a storm to get a clearer profile of the storm, from first flush to the end of the receding discharge; (2) adding an analysis of the dissolved fractions of metals to the sampling plan; (3) installation of an automatic sampler at Bridge 8 to enable sampling earlier in the storms; (4) a one-time sampling and analysis of soils upstream of Bridge 8 for base-line contaminant concentrations; (5) collection of samples from Halawa Stream during low-flow conditions

The Identification of Hail Storms in the Early Stage Using Time Series Analysis

NASA Astrophysics Data System (ADS)

Wang, Ping; Shi, Jinyu; Hou, Jinyi; Hu, Yan

2018-01-01

This study investigates the characteristics of hail storms and cumulonimbus storms in China from 2005 to 2016. Ten features are proposed to identify storm cells that can produce hail, especially in the early stage of hail formation. These features describe hail storms based on three factors: the height and thickness of the cell core, the radar echo intensity, and the overhang structure and the horizontal reflectivity gradient. The 10 features are transformed into two-dimensional comprehensive features by principal component analysis (PCA). The two comprehensive features are named the volume measurement comprehensive feature (VMCF) and the height-gradient comprehensive feature (HGCF). Through an analysis of 49 hail cases and 35 heavy rainfall cases with S-band radar data, the time series exhibit a distinct increase in VMCF or HGCF values in the early stage of a hail storm. However, the VMCF and HGCF values of heavy rainfall events remain relatively stable throughout the storm life cycle. An experiment involving real-storm events, including 31 hail cases and 33 heavy rainfall cases, indicated that the probability of detection of hail storms was 93.33% and the false alarm ratio was 15.66%. In the cases that could be successfully identified as hail storms, 80.00% were detected within 18 min of reaching a hail storm reflectivity of 40 dBZ.

Quantitative detection of mass concentration of sand-dust storms via wind-profiling radar and analysis of Z- M relationship

NASA Astrophysics Data System (ADS)

Wang, Minzhong; Ming, Hu; Ruan, Zheng; Gao, Lianhui; Yang, Di

2018-02-01

With the aim to achieve quantitative monitoring of sand-dust storms in real time, wind-profiling radar is applied to monitor and study the process of four sand-dust storms in the Tazhong area of the Taklimakan Desert. Through evaluation and analysis of the spatial-temporal distribution of reflectivity factor, it is found that reflectivity factor ranges from 2 to 18 dBz under sand-dust storm weather. Using echo power spectrum of radar vertical beams, sand-dust particle spectrum and sand-dust mass concentration at the altitude of 600 ˜ 1500 m are retrieved. This study shows that sand-dust mass concentration reaches 700 μg/m3 under blowing sand weather, 2000 μg/m3 under sand-dust storm weather, and 400 μg/m3 under floating dust weather. The following equations are established to represent the relationship between the reflectivity factor and sand-dust mass concentration: Z = 20713.5 M 0.995 under floating dust weather, Z = 22988.3 M 1.006 under blowing sand weather, and Z = 24584.2 M 1.013 under sand-dust storm weather. The retrieval results from this paper are almost consistent with previous monitoring results achieved by former researchers; thus, it is implied that wind-profiling radar can be used as a new reference device to quantitatively monitor sand-dust storms.

Ionospheric and Thermospheric Response to the 2015 St. Patrick's Day Storm: a Global Multi-Instrumental Overview

NASA Astrophysics Data System (ADS)

Astafyeva, E.; Zakharenkova, I.; Foerster, M.; Doornbos, E.; Encarnacao, J.; Siemes, C.

2015-12-01

We study the ionospheric response to the geomagnetic storm of 17-18 March 2015 (the St. Patrick's Day 2015 storm) that was up to now the strongest in the 24th solar cycle (minimum SYM-H value of -233 nT). For this purpose, we use data of ground-based GPS-receivers and ionosondes, along space-borne instruments onboard the following satellites: Jason-2, GRACE, Terra-SAR-X, the three Swarm satellites (A, B, and C), and GUVI/TIMED. The storm consisted of two successive moderate storms. In the response to the first short storm, a short-term positive effect in the ionospheric vertical electron content (VTEC) occurred at low- and mid-latitudes on the dayside. The second event lasted longer and caused significant and complex storm-time changes around the globe. At high-latitudes, negative storm signatures were recorded in all longitudinal regions. The negative storm phase was found to be strongest in the Asian sector, in particular in the northern hemisphere (NH), but developed globally on March 18 at the beginning of the recovery phase. At mid-latitudes, inverse hemispheric asymmetries occurred in different longitudinal regions: in the European-African sector, positive storm signatures were observed in the NH, whereas in the American sector, a large positive storm occurred in the southern hemisphere (SH), and the NH experienced a negative storm. These observations performed around the spring equinox signify the existence of other impact factors than seasonal dependence for hemispheric asymmetries to occur. At low-latitudes, data from multiple satellites revealed the strongest storm-time effects in the morning (~100-150% enhancement) and post-sunset (~80-100% enhancement) sectors in the topside ionosphere. These dramatic VTEC enhancements were observed at different UT, but around the same area of Eastern Pacific region. To further understand the storm development, we are planning to use thermospheric data from Swarm-C satellite, as well as the data from the electric field instrument onboard the three Swarm satellites.

Numerical Simulation of HIWC Conditions with the Terminal Area Simulation System

NASA Technical Reports Server (NTRS)

Proctor, Fred H.; Switzer, George F.

2016-01-01

Three-dimensional, numerical simulation of a mesoconvective system is conducted in order to better understand conditions associated with High Ice Water Content (HIWC) and its threat to aviation safety. Although peak local values of ice water content may occur early in the storm lifetime, large areas of high concentrations expand with time and persist even when the storm tops begin to warm. The storm canopy which contains HIWC, has low radar reflectivity factor and is fed by an ensemble of regenerating thermal pulses.

The Influence of Ocean on Typhoon Nuri (2008)

NASA Astrophysics Data System (ADS)

Sun, J.; Oey, L. Y.; Xu, F.; Lin, Y.; Huang, S. M.; Chang, R.

2014-12-01

The influence of ocean on typhoon Nuri (2008) is investigated in this study using the WRF numerical model. Typhoon Nuri formed over the warm pool of the western North Pacific. The storm traversed west-northwestward and became a Category 3 typhoon over the Kuroshio east of the Luzon Strait and weakened as it moved across South China Sea. Three types of SST: NCEP RTG_SST (Real-time，global，sea surface temperature) GHRsst (Group for High Resolution Sea Surface Temperature) and SST from the ATOP North Pacific ocean model [Oey et al 2014, JPO] are used in WRF to test the effect of ocean on the intensity of typhoon Nuri. The typhoon intensity and track are also compared with simulations using different microphysics schemes but with fixed SST. The results show that thermodynamic control through ocean response is the dominant factor which determines Nuri's intensity. The simulated intensity agrees well with the observed intensity when ATOP SST is used, while using NCEP SST and GHRsst yield errors both in intensity and timing of maximum intensity. Over the Kuroshio, the thicker depth of 26 ℃ from ATOP provides stronger heating for the correct timing of intensification of Nuri. In South China Sea, the storm weakened because of cooled SST through ocean mixing by inertial resonance. A new way of explaining typhoon intensification though PV is proposed.

Assessing the Performance of GPS Precise Point Positioning Under Different Geomagnetic Storm Conditions during Solar Cycle 24.

PubMed

Luo, Xiaomin; Gu, Shengfeng; Lou, Yidong; Xiong, Chao; Chen, Biyan; Jin, Xueyuan

2018-06-01

The geomagnetic storm, which is an abnormal space weather phenomenon, can sometimes severely affect GPS signal propagation, thereby impacting the performance of GPS precise point positioning (PPP). However, the investigation of GPS PPP accuracy over the global scale under different geomagnetic storm conditions is very limited. This paper for the first time presents the performance of GPS dual-frequency (DF) and single-frequency (SF) PPP under moderate, intense, and super storms conditions during solar cycle 24 using a large data set collected from about 500 international GNSS services (IGS) stations. The global root mean square (RMS) maps of GPS PPP results show that stations with degraded performance are mainly distributed at high-latitude, and the degradation level generally depends on the storm intensity. The three-dimensional (3D) RMS of GPS DF PPP for high-latitude during moderate, intense, and super storms are 0.393 m, 0.680 m and 1.051 m, respectively, with respect to only 0.163 m on quiet day. RMS errors of mid- and low-latitudes show less dependence on the storm intensities, with values less than 0.320 m, compared to 0.153 m on quiet day. Compared with DF PPP, the performance of GPS SF PPP is inferior regardless of quiet or disturbed conditions. The degraded performance of GPS positioning during geomagnetic storms is attributed to the increased ionospheric disturbances, which have been confirmed by our global rate of TEC index (ROTI) maps. Ionospheric disturbances not only lead to the deteriorated ionospheric correction but also to the frequent cycle-slip occurrence. Statistical results show that, compared with that on quiet day, the increased cycle-slip occurrence are 13.04%, 56.52%, and 69.57% under moderate, intense, and super storms conditions, respectively.

Parameterization of synoptic weather systems in the South Atlantic Bight for modeling applications

NASA Astrophysics Data System (ADS)

Wu, Xiaodong; Voulgaris, George; Kumar, Nirnimesh

2017-10-01

An event based, long-term, climatological analysis is presented that allows the creation of coastal ocean atmospheric forcing on the coastal ocean that preserves both frequency of occurrence and event time history. An algorithm is developed that identifies individual storm event (cold fronts, warm fronts, and tropical storms) from meteorological records. The algorithm has been applied to a location along the South Atlantic Bight, off South Carolina, an area prone to cyclogenesis occurrence and passages of atmospheric fronts. Comparison against daily weather maps confirms that the algorithm is efficient in identifying cold fronts and warm fronts, while the identification of tropical storms is less successful. The average state of the storm events and their variability are represented by the temporal evolution of atmospheric pressure, air temperature, wind velocity, and wave directional spectral energy. The use of uncorrected algorithm-detected events provides climatologies that show a little deviation from those derived using corrected events. The effectiveness of this analysis method is further verified by numerically simulating the wave conditions driven by the characteristic wind forcing and comparing the results with the wave climatology that corresponds to each storm type. A high level of consistency found in the comparison indicates that this analysis method can be used for accurately characterizing event-based oceanic processes and long-term storm-induced morphodynamic processes on wind-dominated coasts.

[Dust storms trend in the Capital Circle of China over the past 50 years and its correlation with temperature, precipitation and wind].

PubMed

Chen, Yu-fu; Tang, Hai-ping

2005-01-01

The trends of number of dust storm days of the selected 11 meteorological stations from their established year to 2000 as well as their correlations with temperature, precipitation and wind are revealed. The number of dust storm days of the Capital Circle of China is distinctly variable in space and time. The numbers of dust storm days of the western area are far more than those of the eastern area. The interannual variability of number of dust storm days is remarkable. The number of dust storm days of the following 7 stations, Erlianhaote, Abaga, Xilinhaote, Fengning, Zhangjiakou, Huailai and Beijing, declined along the past decades, but those of the other four stations had no significant upward or downward trends. There is a marked seasonality of the number of dust storm days, and the maximum was in April. The correlation between number of dust storm days and number of days of mean wind velocity > 5 m/s, which is critical wind velocity to entrain sand into the air, was strongest among the three climatic factor. There were significant positive correlations between the number of dust storm days and number of days of mean wind velocity > 5 m/s in 6 stations. The second strongest climatic factor correlated with the number of dust storm days is temperature. There are significant negative correlations between the number of dust storm days and mean annual temperature, mean winter temperature, mean spring temperature in 3 or 4 stations. The correlation between the number of dust storm days and precipitation is weakest. Only one station, Zhurihe, showes significant negative correlation between the number of dust storm days and spring rainfall. There are 4 stations whose number of dust storm days don't significantly correlate with the climate. In the end, the spatial-temporal variability of dust storms and its relation with climate in the Capital Circle of China were discussed thoroughly.

Coastal flooding hazard related to storms and coastal evolution in Valdelagrana spit (Cadiz Bay Natural Park, SW Spain)

NASA Astrophysics Data System (ADS)

Benavente, J.; Del Río, L.; Gracia, F. J.; Martínez-del-Pozo, J. A.

2006-06-01

Mapping of coastal inundation hazard related to storms requires the combination of multiple sources of information regarding meteorological, morphological and dynamic characteristics of both the area at risk and the studied phenomena. Variables such as beach slope, storm wave height or wind speed have traditionally been used, but detailed geomorphological features of the area as well as long-term shoreline evolution trends must also be taken into account in order to achieve more realistic results. This work presents an evaluation of storm flooding hazard in Valdelagrana spit and marshes (SW Spain), considering two types of storm that are characteristic of the area: a modal storm with 1 year of recurrence interval (maximum wave height of 3.3 m), and an extreme storm with 6-10 years of recurrence interval (maximum wave height of 10.6 m), both approaching the coast perpendicularly. After calculating theoretical storm surge elevation, a digital terrain model was made by adjusting topographic data to field work and detailed geomorphological analysis. A model of flooding extent was subsequently developed for each storm type, and then corrected according to the rates of shoreline change in the last decades, which were assessed by means of aerial photographs taking the dune toe as shoreline indicator. Results show that long-term coastline trend represents an important factor in the prediction of flooding extent, since shoreline retreat causes the deterioration of natural coastal defences as dune ridges, thus increasing coastal exposure to high-energy waves. This way, it has been stated that the lack of sedimentary supply plays an important role in spatial variability of inundation extent in Valdelagrana spit. Finally, a hazard map is presented, where calculated coastal retreat rates are employed in order to predict the areas that could be affected by future inundation events.

Areal-reduction factors for the precipitation of the 1-day design storm in Texas

USGS Publications Warehouse

Asquith, William H.

1999-01-01

The reduction of the precipitation depth from a design storm for a point to an effective (mean) depth over a watershed often is important for cost-effective design of hydraulic structures by reducing the volume of precipitation. A design storm for a point is the depth of precipitation that has a specified duration and frequency (recurrence interval). The effective depth can be calculated by multiplying the design-storm depth by an areal-reduction factor (ARF). ARF ranges from 0 to 1, varies with the recurrence interval of the design storm, and is a function of watershed characteristics such as watershed size and shape, geographic location, and time of year that the design storm occurs. This report documents an investigation of ARF by the U.S. Geological Survey, in cooperation with the Texas Department of Transportation, for the 1-day design storm for Austin, Dallas, and Houston, Texas. The ?annual maxima-centered? approach used in this report specifically considers the distribution of concurrent precipitation surrounding an annual precipitation maxima. Unlike previously established approaches, the annual maxima-centered approach does not require the spatial averaging of precipitation nor explicit definition of a representative area of a particular storm in the analysis. Graphs of the relation between ARF and circular watershed area (to about 7,000 square miles) are provided, and a technique to calculate ARF for noncircular watersheds is discussed.

Formation of 30 KeV Proton Isotropic Boundaries During Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Dubyagin, S.; Ganushkina, N. Yu.; Sergeev, V.

2018-05-01

We study the origin of the 30 keV proton isotropic boundary (IB) in the nightside auroral zone during geomagnetic storms, particularly, to address the recent results that the adiabaticity parameter K (ratio of the magnetic field line curvature radius to the particle gyroradius at the equator) on the IB field line can be much larger comparing to its theoretical estimate K ˜ 8 for the field line curvature (FLC) scattering mechanism. During nine storms in 2011-2013, we investigate ˜2,000 IBs observed by low-altitude Polar Operational Environmental Satellites (POES) satellites and apply the TS05 magnetospheric model to estimate the K value in the equatorial part of the IB field line. The statistical distribution of the estimated K parameter, while being rather broad, is centered on K = 9-13. For smaller subset of ˜250 IBs, the concurrent magnetic field measurements on board Time History of Events and Macroscale Interaction During Substorms probes in the equatorial magnetotail were used to correct the estimated K-values accounting for the TS05 deviations from the real magnetic configuration. After correction, the K distribution becomes narrower, being still centered on K = 9-12. Different estimates give percentages of events with K < 13, which can be attributed to IBs formed by FLC scattering, between 60% and 80%. Finally, we have not found any dependence of the K distribution on magnetic local time and IB latitude, except for events with IB located at extremely low latitudes (<59°). These findings imply that the FLC scattering is a dominant mechanism of IB formation operating in a variety of magnetospheric conditions.

RainyDay: An Online, Open-Source Tool for Physically-based Rainfall and Flood Frequency Analysis

NASA Astrophysics Data System (ADS)

Wright, D.; Yu, G.; Holman, K. D.

2017-12-01

Flood frequency analysis in ungaged or changing watersheds typically requires rainfall intensity-duration-frequency (IDF) curves combined with hydrologic models. IDF curves only depict point-scale rainfall depth, while true rainstorms exhibit complex spatial and temporal structures. Floods result from these rainfall structures interacting with watershed features such as land cover, soils, and variable antecedent conditions as well as river channel processes. Thus, IDF curves are traditionally combined with a variety of "design storm" assumptions such as area reduction factors and idealized rainfall space-time distributions to translate rainfall depths into inputs that are suitable for flood hydrologic modeling. The impacts of such assumptions are relatively poorly understood. Meanwhile, modern precipitation estimates from gridded weather radar, grid-interpolated rain gages, satellites, and numerical weather models provide more realistic depictions of rainfall space-time structure. Usage of such datasets for rainfall and flood frequency analysis, however, are hindered by relatively short record lengths. We present RainyDay, an open-source stochastic storm transposition (SST) framework for generating large numbers of realistic rainfall "scenarios." SST "lengthens" the rainfall record by temporal resampling and geospatial transposition of observed storms to extract space-time information from regional gridded rainfall data. Relatively short (10-15 year) records of bias-corrected radar rainfall data are sufficient to estimate rainfall and flood events with much longer recurrence intervals including 100-year and 500-year events. We describe the SST methodology as implemented in RainyDay and compare rainfall IDF results from RainyDay to conventional estimates from NOAA Atlas 14. Then, we demonstrate some of the flood frequency analysis properties that are possible when RainyDay is integrated with a distributed hydrologic model, including robust estimation of flood hazards in a changing watershed. The U.S. Bureau of Reclamation is supporting the development of a web-based variant of RainyDay, a "beta" version of which is available at http://her.cee.wisc.edu/projects/rainyday/.

Evaluation of NWP-based Satellite Precipitation Error Correction with Near-Real-Time Model Products and Flood-inducing Storms

NASA Astrophysics Data System (ADS)

Zhang, X.; Anagnostou, E. N.; Schwartz, C. S.

2017-12-01

Satellite precipitation products tend to have significant biases over complex terrain. Our research investigates a statistical approach for satellite precipitation adjustment based solely on numerical weather simulations. This approach has been evaluated in two mid-latitude (Zhang et al. 2013*1, Zhang et al. 2016*2) and three topical mountainous regions by using the WRF model to adjust two high-resolution satellite products i) National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center morphing technique (CMORPH) and ii) Global Satellite Mapping of Precipitation (GSMaP). Results show the adjustment effectively reduces the satellite underestimation of high rain rates, which provides a solid proof-of-concept for continuing research of NWP-based satellite correction. In this study we investigate the feasibility of using NCAR Real-time Ensemble Forecasts*3 for adjusting near-real-time satellite precipitation datasets over complex terrain areas in the Continental United States (CONUS) such as Olympic Peninsula, California coastal mountain ranges, Rocky Mountains and South Appalachians. The research will focus on flood-inducing storms occurred from May 2015 to December 2016 and four satellite precipitation products (CMORPH, GSMaP, PERSIANN-CCS and IMERG). The error correction performance evaluation will be based on comparisons against the gauge-adjusted Stage IV precipitation data. *1 Zhang, Xinxuan, et al. "Using NWP simulations in satellite rainfall estimation of heavy precipitation events over mountainous areas." Journal of Hydrometeorology 14.6 (2013): 1844-1858. *2 Zhang, Xinxuan, et al. "Hydrologic Evaluation of NWP-Adjusted CMORPH Estimates of Hurricane-Induced Precipitation in the Southern Appalachians." Journal of Hydrometeorology 17.4 (2016): 1087-1099. *3 Schwartz, Craig S., et al. "NCAR's experimental real-time convection-allowing ensemble prediction system." Weather and Forecasting 30.6 (2015): 1645-1654.

Episodic acidification of a coastal plain stream in Virginia

USGS Publications Warehouse

O'Brien, A. K.; Eshleman, K.N.

1996-01-01

This study investigates the episodic acidification of Reedy Creek, a wetland-influenced coastal plain stream near Richmond, Virginia. Primary objectives of the study were to quantify the episodic variability of acid- base chemistry in Reedy Creek, to examine the seasonal variability in episodic response and to explain the hydrological and geochemical factors that contribute to episodic acidification. Chemical response was similar in each of the seven storms examined, however, the ranges in concentrations observed were commonly greater in summer/fall storms than in winter/spring storms. An increase in SO4/2- concentration with discharge was observed during all storms and peak concentration occurred at or near peak flow. Small increases in Mg2+, Ca2+, K+ concentrations and dissolved organic carbon (DOC) were observed during most storms. At the same time, ANC, Na+ and Cl- concentrations usually decreased with increasing discharge. In summer/fall storms, the absolute increase in SO4/2- concentration was one-third to 15 times the increase observed in winter/spring storms; the decrease in ANC during summer/fall storms was usually within the range of the decrease observed in winter/spring storms. In contrast, the decrease in Na+ and Cl- concentrations during winter/spring storms was much greater than that observed during summer/fall storms. Data show that while base flow anion deficit was higher in summer/fall than in winter/spring, anion deficit decreased during most summer/fall storms. In contrast, base flow anion deficit was lower in spring and winter, but increased during winter/spring storms. Increased SO4/2- concentration was the main cause of episodic acidification during storms at Reedy Creek, but increased anion deficit indicates organic acids may contribute to episodic acidification during winter/spring storms. Changes in SO4/2- concentration coincident with the hydrograph rise indicate quick routing of water through the watershed. Saturation overland flow appears to be the likely mechanism by which solutes are transported to the stream during storm flow.

Investigating storm-time magnetospheric electrodynamics: Multi-spacecraft observations of the June 22, 2015 magnetic storm

NASA Astrophysics Data System (ADS)

Reiff, P. H.; Sazykin, S. Y.; Bala, R.; Coffey, V. N.; Chandler, M. O.; Minow, J. I.; Anderson, B. J.; Wolf, R.; Huba, J.; Baker, D. N.; Mauk, B.; Russell, C. T.

2015-12-01

The magnetic storm that commenced on June 22, 2015 was one of the largest storms in the current solar cycle. Availability of in situ observations from Magnetospheric Multiscale (MMS), the Van Allen Probes (VAP), and THEMIS in the magnetosphere, field-aligned currents from AMPERE, as well as the ionospheric data from the Floating Potential Measurement Unit (FPMU) instrument suite on board the International Space Station (ISS) represents an exciting opportunity to analyze storm-related dynamics. Our real-time space weather alert system sent out a "red alert" warning users of the event 2 hours in advance, correctly predicting Kp indices greater than 8. During this event, the MMS observatories were taking measurements in the magnetotail, VAP were in the inner magnetosphere, THEMIS was on the dayside, and the ISS was orbiting at 400 km every 90 minutes. Among the initial findings are the crossing of the dayside magnetopause into the region earthward of 8 RE, strong dipolarizations in the MMS magnetometer data, and dropouts in the particle fluxes seen by the MMS FPI instrument suite. At ionospheric altitudes, the FMPU measurements of the ion densities show dramatic post-sunset depletions at equatorial latitudes that are correlated with the particle flux dropouts measured by the MMS FPI. AMPERE data show highly variable currents varying from intervals of intense high latitude currents to currents at maximum polar cap expansion to 50 deg MLAT and exceeding 20 MA. In this paper, we use numerical simulations with global magnetohydrodynamic (MHD) models and the Rice Convection Model (RCM) of the inner magnetosphere in an attempt to place the observations in the context of storm-time global electrodynamics and cross-check the simulation global Birkeland currents with AMPERE distributions. Specifically, we will look at model-predicted effects of dipolarizations and the global convection on the inner magnetosphere via data-model comparison.

Correction of Dual-PRF Doppler Velocity Outliers in the Presence of Aliasing

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

Altube, Patricia; Bech, Joan; Argemí, Oriol

In Doppler weather radars, the presence of unfolding errors or outliers is a well-known quality issue for radial velocity fields estimated using the dual–pulse repetition frequency (PRF) technique. Postprocessing methods have been developed to correct dual-PRF outliers, but these need prior application of a dealiasing algorithm for an adequate correction. Our paper presents an alternative procedure based on circular statistics that corrects dual-PRF errors in the presence of extended Nyquist aliasing. The correction potential of the proposed method is quantitatively tested by means of velocity field simulations and is exemplified in the application to real cases, including severe storm events.more » The comparison with two other existing correction methods indicates an improved performance in the correction of clustered outliers. The technique we propose is well suited for real-time applications requiring high-quality Doppler radar velocity fields, such as wind shear and mesocyclone detection algorithms, or assimilation in numerical weather prediction models.« less

Correction of Dual-PRF Doppler Velocity Outliers in the Presence of Aliasing

DOE PAGES

Altube, Patricia; Bech, Joan; Argemí, Oriol; ...

2017-07-18

In Doppler weather radars, the presence of unfolding errors or outliers is a well-known quality issue for radial velocity fields estimated using the dual–pulse repetition frequency (PRF) technique. Postprocessing methods have been developed to correct dual-PRF outliers, but these need prior application of a dealiasing algorithm for an adequate correction. Our paper presents an alternative procedure based on circular statistics that corrects dual-PRF errors in the presence of extended Nyquist aliasing. The correction potential of the proposed method is quantitatively tested by means of velocity field simulations and is exemplified in the application to real cases, including severe storm events.more » The comparison with two other existing correction methods indicates an improved performance in the correction of clustered outliers. The technique we propose is well suited for real-time applications requiring high-quality Doppler radar velocity fields, such as wind shear and mesocyclone detection algorithms, or assimilation in numerical weather prediction models.« less

Wavefront correction using machine learning methods for single molecule localization microscopy

NASA Astrophysics Data System (ADS)

Tehrani, Kayvan F.; Xu, Jianquan; Kner, Peter

2015-03-01

Optical Aberrations are a major challenge in imaging biological samples. In particular, in single molecule localization (SML) microscopy techniques (STORM, PALM, etc.) a high Strehl ratio point spread function (PSF) is necessary to achieve sub-diffraction resolution. Distortions in the PSF shape directly reduce the resolution of SML microscopy. The system aberrations caused by the imperfections in the optics and instruments can be compensated using Adaptive Optics (AO) techniques prior to imaging. However, aberrations caused by the biological sample, both static and dynamic, have to be dealt with in real time. A challenge for wavefront correction in SML microscopy is a robust optimization approach in the presence of noise because of the naturally high fluctuations in photon emission from single molecules. Here we demonstrate particle swarm optimization for real time correction of the wavefront using an intensity independent metric. We show that the particle swarm algorithm converges faster than the genetic algorithm for bright fluorophores.

The Role of Ionospheric O+ in Forming the Storm-time Ring Current

NASA Astrophysics Data System (ADS)

Kistler, L. M.; Mouikis, C.; Menz, A.; Bingham, S.

2017-12-01

During storm times, the particle pressure that creates the storm-time ring current in the inner magnetosphere can be dominated by O+. This is surprising, as the immediate source for the ring current is the nightside plasma sheet, and O+ is usually not the dominant species in the plasma sheet. In this talk we examine the many factors that lead to this result. The O+ outflow is enhanced during geomagnetically active times. The transport paths of O+ and H+ are different, such that the O+ that reaches the near-earth plasma sheet is more energetic than H+. The source spectrum in the near-earth plasma sheet can be harder for O+ than for H+, perhaps due to substorm injections, so that the more energetic plasma has a higher O+/H+ ratio. And finally the plasma sheet O+ can be more abundant towards the beginning of the storm, when the convection is largest, so the enhanced O+ is brought the deepest into the inner magnetosphere. We will discuss the interrelationships between these different effects as well as the ways in which O+ itself may influence the system.

Analysis of Storm Surge in Hong Kong

NASA Astrophysics Data System (ADS)

Kao, W. H.

2017-12-01

A storm surge is a type of coastal flood that is caused by low-pressure systems such as tropical cyclones. Storm surges caused by tropical cyclones can be very powerful and damaging, as they can flood coastal areas, and even destroy infrastructure in serious cases. Some serious cases of storm surges leading to more than thousands of deaths include Hurricane Katrina (2005) in New Orleans and Typhoon Haiyan (2013) in Philippines. Hong Kong is a coastal city that is prone to tropical cyclones, having an average of 5-6 tropical cyclones entering 500km range of Hong Kong per year. Storm surges have seriously damaged Hong Kong in the past, causing more than 100 deaths by Typhoon Wanda (1962), and leading to serious damage to Tai O and Cheung Chau by Typhoon Hagupit (2008). To prevent economic damage and casualties from storm surges, accurately predicting the height of storm surges and giving timely warnings to citizens is very important. In this project, I will be analyzing how different factors affect the height of storm surge, mainly using data from Hong Kong. These factors include the windspeed in Hong Kong, the atmospheric pressure in Hong Kong, the moon phase, the wind direction, the intensity of the tropical cyclone, distance between the tropical cyclone and Hong Kong, the direction of the tropical cyclone relative to Hong Kong, the speed of movement of the tropical cyclone and more. My findings will also be compared with cases from other places, to see if my findings also apply for other places.

Predicting thunderstorm evolution using ground-based lightning detection networks

NASA Technical Reports Server (NTRS)

Goodman, Steven J.

1990-01-01

Lightning measurements acquired principally by a ground-based network of magnetic direction finders are used to diagnose and predict the existence, temporal evolution, and decay of thunderstorms over a wide range of space and time scales extending over four orders of magnitude. The non-linear growth and decay of thunderstorms and their accompanying cloud-to-ground lightning activity is described by the three parameter logistic growth model. The growth rate is shown to be a function of the storm size and duration, and the limiting value of the total lightning activity is related to the available energy in the environment. A new technique is described for removing systematic bearing errors from direction finder data where radar echoes are used to constrain site error correction and optimization (best point estimate) algorithms. A nearest neighbor pattern recognition algorithm is employed to cluster the discrete lightning discharges into storm cells and the advantages and limitations of different clustering strategies for storm identification and tracking are examined.

Observations and global numerical modelling of the St. Patrick's Day 2015 geomagnetic storm event

NASA Astrophysics Data System (ADS)

Foerster, M.; Prokhorov, B. E.; Doornbos, E.; Astafieva, E.; Zakharenkova, I.

2017-12-01

With a sudden storm commencement (SSC) at 04:45 UT on St. Patrick's day 2015 started the most severe geomagnetic storm in solar cycle 24. It appeared as a two-stage geomagnetic storm with a minimum SYM-H value of -233 nT. In the response to the storm commencement in the first activation, a short-term positive effect in the ionospheric vertical electron content (VTEC) occurred at low- and mid-latitudes on the dayside. The second phase commencing around 12:30 UT lasted longer and caused significant and complex storm-time changes around the globe with hemispherical different ionospheric storm reactions in different longitudinal ranges. Swarm-C observations of the neutral mass density variation along the orbital path as well as Langmuir probe plasma and magnetometer measurements of all three Swarm satellites and global TEC records are used for physical interpretations and modelling of the positive/negative storm scenario. These observations pose a challenge for the global numerical modelling of thermosphere-ionosphere storm processes as the storm, which occurred around spring equinox, obviously signify the existence of other impact factors than seasonal dependence for hemispheric asymmetries to occur. Numerical simulation trials using the Potsdam version of the Upper Atmosphere Model (UAM-P) are presented to explain these peculiar M-I-T storm processes.

Hydrometeorological and statistical analyses of heavy rainfall in Midwestern USA

NASA Astrophysics Data System (ADS)

Thorndahl, S.; Smith, J. A.; Krajewski, W. F.

2012-04-01

During the last two decades the mid-western states of the United States of America has been largely afflicted by heavy flood producing rainfall. Several of these storms seem to have similar hydrometeorological properties in terms of pattern, track, evolution, life cycle, clustering, etc. which raise the question if it is possible to derive general characteristics of the space-time structures of these heavy storms. This is important in order to understand hydrometeorological features, e.g. how storms evolve and with what frequency we can expect extreme storms to occur. In the literature, most studies of extreme rainfall are based on point measurements (rain gauges). However, with high resolution and quality radar observation periods exceeding more than two decades, it is possible to do long-term spatio-temporal statistical analyses of extremes. This makes it possible to link return periods to distributed rainfall estimates and to study precipitation structures which cause floods. However, doing these statistical frequency analyses of rainfall based on radar observations introduces some different challenges, converting radar reflectivity observations to "true" rainfall, which are not problematic doing traditional analyses on rain gauge data. It is for example difficult to distinguish reflectivity from high intensity rain from reflectivity from other hydrometeors such as hail, especially using single polarization radars which are used in this study. Furthermore, reflectivity from bright band (melting layer) should be discarded and anomalous propagation should be corrected in order to produce valid statistics of extreme radar rainfall. Other challenges include combining observations from several radars to one mosaic, bias correction against rain gauges, range correction, ZR-relationships, etc. The present study analyzes radar rainfall observations from 1996 to 2011 based the American NEXRAD network of radars over an area covering parts of Iowa, Wisconsin, Illinois, and Lake Michigan. The radar observations are processed using Hydro-NEXRAD algorithms in order to produce rainfall estimates with a spatial resolution of 1 km and a temporal resolution of 15 min. The rainfall estimates are bias-corrected on a daily basis using a network of rain gauges. Besides a thorough evaluation of the different challenges in investigating heavy rain as described above the study includes suggestions for frequency analysis methods as well as studies of hydrometeorological features of single events.

Tree Species Traits but Not Diversity Mitigate Stem Breakage in a Subtropical Forest following a Rare and Extreme Ice Storm

PubMed Central

Nadrowski, Karin; Pietsch, Katherina; Baruffol, Martin; Both, Sabine; Gutknecht, Jessica; Bruelheide, Helge; Heklau, Heike; Kahl, Anja; Kahl, Tiemo; Niklaus, Pascal; Kröber, Wenzel; Liu, Xiaojuan; Mi, Xiangcheng; Michalski, Stefan; von Oheimb, Goddert; Purschke, Oliver; Schmid, Bernhard; Fang, Teng; Welk, Erik; Wirth, Christian

2014-01-01

Future climates are likely to include extreme events, which in turn have great impacts on ecological systems. In this study, we investigated possible effects that could mitigate stem breakage caused by a rare and extreme ice storm in a Chinese subtropical forest across a gradient of forest diversity. We used Bayesian modeling to correct stem breakage for tree size and variance components analysis to quantify the influence of taxon, leaf and wood functional traits, and stand level properties on the probability of stem breakage. We show that the taxon explained four times more variance in individual stem breakage than did stand level properties; trees with higher specific leaf area (SLA) were less susceptible to breakage. However, a large part of the variation at the taxon scale remained unexplained, implying that unmeasured or undefined traits could be used to predict damage caused by ice storms. When aggregated at the plot level, functional diversity and wood density increased after the ice storm. We suggest that for the adaption of forest management to climate change, much can still be learned from looking at functional traits at the taxon level. PMID:24879434

How well do the GCMs/RCMs capture the multi-scale temporal variability of precipitation in the Southwestern United States?

NASA Astrophysics Data System (ADS)

Jiang, Peng; Gautam, Mahesh R.; Zhu, Jianting; Yu, Zhongbo

2013-02-01

SummaryMulti-scale temporal variability of precipitation has an established relationship with floods and droughts. In this paper, we present the diagnostics on the ability of 16 General Circulation Models (GCMs) from Bias Corrected and Downscaled (BCSD) World Climate Research Program's (WCRP's) Coupled Model Inter-comparison Project Phase 3 (CMIP3) projections and 10 Regional Climate Models (RCMs) that participated in the North American Regional Climate Change Assessment Program (NARCCAP) to represent multi-scale temporal variability determined from the observed station data. Four regions (Los Angeles, Las Vegas, Tucson, and Cimarron) in the Southwest United States are selected as they represent four different precipitation regions classified by clustering method. We investigate how storm properties and seasonal, inter-annual, and decadal precipitation variabilities differed between GCMs/RCMs and observed records in these regions. We find that current GCMs/RCMs tend to simulate longer storm duration and lower storm intensity compared to those from observed records. Most GCMs/RCMs fail to produce the high-intensity summer storms caused by local convective heat transport associated with the summer monsoon. Both inter-annual and decadal bands are present in the GCM/RCM-simulated precipitation time series; however, these do not line up to the patterns of large-scale ocean oscillations such as El Nino/La Nina Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Our results show that the studied GCMs/RCMs can capture long-term monthly mean as the examined data is bias-corrected and downscaled, but fail to simulate the multi-scale precipitation variability including flood generating extreme events, which suggests their inadequacy for studies on floods and droughts that are strongly associated with multi-scale temporal precipitation variability.

Total Lightning and Radar Storm Characteristics Associated with Severe Storms in Central Florida

NASA Technical Reports Server (NTRS)

Goodman, Steven J; Raghavan, R.; Buechler, Dennis; Hodanish, S.; Sharp, D.; Williams, E.; Boldi, B.; Matlin, A.; Weber, M.

1998-01-01

This paper examines the three dimensional characteristics of lightning flashes and severe storms observed in Central Florida during 1997-1998. The lightning time history of severe and tornadic storms were captured during the on-going ground validation campaign supporting the Lightning Imaging Sensor (LIS) experiment on the Tropical Rainfall Measuring Mission (TRMM). The ground validation campaign is a collaborative experiment that began in 1997 and involves scientists at the Global Hydrology and Climate Center, MIT/Lincoln Laboratories, and the NWS Forecast Office at Melbourne, FL. Lightning signatures that may provide potential early warning of severe storms are being evaluated by the forecasters at the NWS/MLB office. Severe storms with extreme flash rates sometimes exceeding 300 per minute and accompanying rapid increases in flash rate prior to the onset of the severe weather (hall, damaging winds, tornadoes) have been reported by Hodanish et al. and Williams et al. (1998-this conference). We examine the co-evolving changes in storm structure (mass, echo top, shear, latent heat release) and kinematics associated with these extreme and rapid flash rate changes over time. The flash frequency and density are compared with the three dimensional radar reflectivity structure of the storm to help interpret the possible mechanisms producing the extreme and rapidly increasing flash rates. For two tornadic storms examined thus far, we find the burst of lightning is associated with the development of upper level rotation in the storm. In one case, the lightning burst follows the formation of a bounded weak echo region (BWER). The flash rates diminish with time as the rotation develops to the ground in conjunction with the decent of the reflectivity core. Our initial findings suggest the dramatic increase of flash rates is associated with a sudden and dramatic increase in storm updraft intensity which we hypothesize is stretching vertical vorticity as well as enhancing the development of the mixed phase region of the storm. We discuss the importance of these factors in producing both the observed extreme flash rates and the severe weather that follows in these storms and others to be presented.

Impact of wind-induced microsites and disturbance severity on tree regeneration patterns: Results from the first post-storm decade

Treesearch

Floor Vodde; Kalev Jogiste; Jeroen Engelhart; Lee E. Frelich; W. Keith Moser; Alan Sims; Marek Metslaid

2015-01-01

In two hemiboreal mixed spruce-hardwood forests in north-east Estonia, we studied (1) which factors affect tree regeneration survival and development during the first post-storm decade and (2) how these effects change in time. Regeneration height and mortality of the tree species black alder (Alnus glutinosa (L.) J. Gaertn.), birch (Betula pendula Roth., Betula...

Relationships of storm-time changes in thermospheric mass density with solar wind/IMF parameters and ring current index of Sym-H

NASA Astrophysics Data System (ADS)

Zhou, Yunliang; Ma, S. Y.; Xiong, Chao; Luehr, Hermann

The total air mass densities at about 500 km altitude are derived using super-STAR accelerom-eter measurements onboard GRACE satellites for 25 great magnetic storms with minimum Dst less than 100 nT during 2002 to 2006 years. Taking NRLMSISE-00 model-predicted densities without active ap index input as a reference baseline of quiet-time mass density, the storm-time changes in upper thermospheric mass densities are obtained by subtraction for all the storm events and sorted into different grids of latitude by local time sector. The relationships of the storm-time density changes with various interplanetary parameters and magnetospheric ring current index of Sym-H are statistically investigated. The parameters include Akasofu energy coupling function, the merging electric field Em, the magnitude of IMF component in the GSM y-z plane etc. as calculated from OMNI data at 1 AU. It is found that the storm-time changes in the upper thermospheric mass density have the best linear correlation with the Sym-H index in general, showing nearly zero time delay at low-latitudes and a little time ahead at high-latitudes for most cases. Unexpectedly, the magnitude of IMF component in the y-z plane, Byz, shows correlation with storm-time mass density changes better and closer than Akasofu function and even Em. And, the mass density changes lag behind Byz about 1-4 hours for most cases at low-latitudes. The correlations considered above are local time dependent, showing the lowest at dusk sectors. For the largest superstorm of November 2003, the changes in mass density are correlated very closely with Byz, Em, and Sym-H index, showing correlation coefficients averaged over all latitudes in noon sector as high as 0.93, 0.91 and 0.90 separately. The physical factors controlling the lag times between the mass density changes at mid-low-latitudes and the interplanetary parameter variations are also analyzed. The results in this study may pro-vide useful suggestions for establishing empirical model to predict storm-time changes in upper thermospheric mass density. This work is supported by NSFC (No. 40804049) and Doctoral Fund of Ministry of Education of China (No. 200804860012).

Quantifying mountain block recharge by means of catchment-scale storage-discharge relationships

NASA Astrophysics Data System (ADS)

Ajami, Hoori; Troch, Peter A.; Maddock, Thomas, III; Meixner, Thomas; Eastoe, Chris

2011-04-01

Despite the importance of mountainous catchments for providing freshwater resources, especially in semi-arid regions, little is known about key hydrological processes such as mountain block recharge (MBR). Here we implement a data-based method informed by isotopic data to quantify MBR rates using recession flow analysis. We applied our hybrid method in a semi-arid sky island catchment in southern Arizona, United States. Sabino Creek is a 91 km2 catchment with its sources near the summit of the Santa Catalina Mountains northeast of Tucson. Southern Arizona's climate has two distinct wet seasons separated by prolonged dry periods. Winter frontal storms (November-March) provide about 50% of annual precipitation, and summers are dominated by monsoon convective storms from July to September. Isotope analyses of springs and surface water in the Sabino Creek catchment indicate that streamflow during dry periods is derived from groundwater storage in fractured bedrock. Storage-discharge relationships are derived from recession flow analysis to estimate changes in storage during wet periods. To provide reliable estimates, several corrections and improvements to classic base flow recession analysis are considered. These corrections and improvements include adaptive time stepping, data binning, and the choice of storage-discharge functions. Our analysis shows that (1) incorporating adaptive time steps to correct for streamflow measurement errors improves the coefficient of determination, (2) the quantile method is best for streamflow data binning, (3) the choice of the regression model is critical when the stage-discharge function is used to predict changes in bedrock storage beyond the maximum observed flow in the catchment, and (4) the use of daily or night-time hourly streamflow does not affect the form of the storage-discharge relationship but will impact MBR estimates because of differences in the observed range of streamflow in each series.

Pore pressure diffusion and the hydrologic response of nearly saturated, thin landslide deposits of rainfall

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

Haneberg, W.C.

1991-11-01

Previous workers have correlated slope failures during rainstorms with rainfall intensity, rainfall duration, and seasonal antecedent rainfall. This note shows how such relationships can be interpreted using a periodic steady-state solution to the well-known linear pressure diffusion equation. Normalization of the governing equation yields a characteristic response time that is a function of soil thickness, saturated hydraulic conductivity, and pre-storm effective porosity, and which is analogous to the travel time of a piston wetting front. The effects of storm frequency and magnitude are also successfully quantified using dimensionless attenuation factors and lag times.

DSD Characteristics of a Mid-Winter Tornadic Storm Using C-Band Polarimetric Radar and Two 2D-Video Disdrometers

NASA Technical Reports Server (NTRS)

Thurai, M.; Petersen, W. A.; Carey, L. A.

2010-01-01

Drop size distributions in an evolving tornadic storm are examined using C-band polarimetric radar observations and two 2D-video disdrometers. The E-F2 storm occurred in mid-winter (21 January 2010) in northern Alabama, USA, and caused widespread damage. The evolution of the storm occurred within the C-band radar coverage and moreover, several minutes prior to touch down, the storm passed over a site where several disdrometers including two 2D video disdrometers (2DVD) had been installed. One of the 2DVDs is a low profile unit and the other is a new next generation compact unit currently undergoing performance evaluation. Analyses of the radar data indicate that the main region of precipitation should be treated as a "big-drop" regime case. Even the measured differential reflectivity values (i.e. without attenuation correction) were as high as 6-7 dB within regions of high reflectivity. Standard attenuation-correction methods using differential propagation phase have been "fine tuned" to be applicable to the "big drop" regime. The corrected reflectivity and differential reflectivity data are combined with the co-polar correlation coefficient and specific differential phase to determine the mass-weighted mean diameter, Dm, and the width of the mass spectrum, (sigma)M, as well as the intercept parameter , Nw. Significant areas of high Dm (3-4 mm) were retrieved within the main precipitation areas of the tornadic storm. The "big drop" regime assumption is substantiated by the two sets of 2DVD measurements. The Dm values calculated from 1-minute drop size distributions reached nearly 4 mm, whilst the maximum drop diameters were over 6 mm. The fall velocity measurements from the 2DVD indicate almost all hydrometeors to be fully melted at ground level. Drop shapes for this event are also being investigated from the 2DVD camera data.

Geometric effects of ICMEs on geomagnetic storms

NASA Astrophysics Data System (ADS)

Cho, KyungSuk; Lee, Jae-Ok

2017-04-01

It has been known that the geomagnetic storm is occurred by the interaction between the Interplanetary Coronal Mass Ejection (ICME) and the Earth's magnetosphere; especially, the southward Bz component of ICME is thought as the main trigger. In this study, we investigate the relationship between Dst index and solar wind conditions; which are the southward Bz, electric field (VBz), and time integral of electric field as well as ICME parameters derived from toroidal fitting model in order to find what is main factor to the geomagnetic storm. We also inspect locations of Earth in ICMEs to understand the geometric effects of the Interplanetary Flux Ropes (IFRs) on the geomagnetic storms. Among 59 CDAW ICME lists, we select 30 IFR events that are available by the toroidal fitting model and classify them into two sub-groups: geomagnetic storms associated with the Magnetic Clouds (MCs) and the compression regions ahead of the MCs (sheath). The main results are as follows: (1) The time integral of electric field has a higher correlation coefficient (cc) with Dst index than the other parameters: cc=0.85 for 25 MC events and cc=0.99 for 5 sheath events. (2) The sheath associated intense storms (Dst ≤-100nT) having usually occur at flank regions of ICMEs while the MC associated intense storms occur regardless of the locations of the Earth in ICMEs. The strength of a geomagnetic storm strongly depends on electric field of IFR and durations of the IFR passages through the Earth.

Variation of Magnetic Field (By , Bz) Polarity and Statistical Analysis of Solar Wind Parameters during the Magnetic Storm Period

NASA Astrophysics Data System (ADS)

Moon, Ga-Hee

2011-06-01

It is generally believed that the occurrence of a magnetic storm depends upon the solar wind conditions, particularly the southward interplanetary magnetic field (IMF) component. To understand the relationship between solar wind parameters and magnetic storms, variations in magnetic field polarity and solar wind parameters during magnetic storms are examined. A total of 156 storms during the period of 1997~2003 are used. According to the interplanetary driver, magnetic storms are divided into three types, which are coronal mass ejection (CME)-driven storms, co-rotating interaction region (CIR)-driven storms, and complicated type storms. Complicated types were not included in this study. For this purpose, the manner in which the direction change of IMF By and Bz components (in geocentric solar magnetospheric coordinate system coordinate) during the main phase is related with the development of the storm is examined. The time-integrated solar wind parameters are compared with the time-integrated disturbance storm time (Dst) index during the main phase of each magnetic storm. The time lag with the storm size is also investigated. Some results are worth noting: CME-driven storms, under steady conditions of Bz < 0, represent more than half of the storms in number. That is, it is found that the average number of storms for negative sign of IMF Bz (T1~T4) is high, at 56.4%, 53.0%, and 63.7% in each storm category, respectively. However, for the CIR-driven storms, the percentage of moderate storms is only 29.2%, while the number of intense storms is more than half (60.0%) under the Bz < 0 condition. It is found that the correlation is highest between the time-integrated IMF Bz and the time-integrated Dst index for the CME-driven storms. On the other hand, for the CIR-driven storms, a high correlation is found, with the correlation coefficient being 0.93, between time-integrated Dst index and time-integrated solar wind speed, while a low correlation, 0.51, is found between timeintegrated Bz and time-integrated Dst index. The relationship between storm size and time lag in terms of hours from Bz minimum to Dst minimum values is investigated. For the CME-driven storms, time lag of 26% of moderate storms is one hour, whereas time lag of 33% of moderate storms is two hours for the CIR-driven storms. The average values of solar wind parameters for the CME and CIR-driven storms are also examined. The average values of |Dstmin| and |Bzmin| for the CME-driven storms are higher than those of CIR-driven storms, while the average value of temperature is lower.

Non-Tidal Ocean Loading Correction for the Argentinean-German Geodetic Observatory Using an Empirical Model of Storm Surge for the Río de la Plata

NASA Astrophysics Data System (ADS)

Oreiro, F. A.; Wziontek, H.; Fiore, M. M. E.; D'Onofrio, E. E.; Brunini, C.

2018-05-01

The Argentinean-German Geodetic Observatory is located 13 km from the Río de la Plata, in an area that is frequently affected by storm surges that can vary the level of the river over ±3 m. Water-level information from seven tide gauge stations located in the Río de la Plata are used to calculate every hour an empirical model of water heights (tidal + non-tidal component) and an empirical model of storm surge (non-tidal component) for the period 01/2016-12/2016. Using the SPOTL software, the gravimetric response of the models and the tidal response are calculated, obtaining that for the observatory location, the range of the tidal component (3.6 nm/s2) is only 12% of the range of the non-tidal component (29.4 nm/s2). The gravimetric response of the storm surge model is subtracted from the superconducting gravimeter observations, after applying the traditional corrections, and a reduction of 7% of the RMS is obtained. The wavelet transform is applied to the same series, before and after the non-tidal correction, and a clear decrease in the spectral energy in the periods between 2 and 12 days is identify between the series. Using the same software East, North and Up displacements are calculated, and a range of 3, 2, and 11 mm is obtained, respectively. The residuals obtained after applying the non-tidal correction allow to clearly identify the influence of rain events in the superconducting gravimeter observations, indicating the need of the analysis of this, and others, hydrological and geophysical effects.

Thyroid storm. A review of cases at University of California, San Francisco.

PubMed

Roizen, M; Becker, C E

1971-10-01

Retrospective study of the diagnosis and management of the 8 cases of thyroid storm in a series of 400 hyperthyroid patients led to conclusion that thyroid storm is a clinical diagnosis based on a life-endangering illness in a hyperthyroid patient whose hyperthyroidism has been severely exacerbated by a serious precipitating illness, and that storm is manifest by the symptoms of hyperpyrexia, tachycardia and striking alterations in consciousness. No laboratory tests were diagnostic of storm, and the underlying precipitating cause of thyroid storm was the major determinant of survival. Vigorous therapy must include blocking synthesis of thyroid hormones with antithyroid drugs, blocking release of preformed hormone with iodine, meticulous attention to hydration and supportive therapy, as well as correction of precipitating cause of storm. The blocking of the sympathetic nervous system with reserpine or guanethidine or with alpha and beta blocking drugs may be exceedingly hazardous and requires skillful management and constant monitoring in a critically ill patient.

Settling characteristics of fine-grained sediments used in Louisiana coastal land building and restoration projects

NASA Astrophysics Data System (ADS)

Ghose Hajra, M.

2016-02-01

Coastal property development, sea level rise, geologic subsidence, loss of barrier islands, increasing number and intensity of coastal storms and other factors have resulted in water quality degradation, wetlands loss, reduced storm and surge protection, ground settlement, and other challenges in coastal areas throughout the world. One of the goals towards reestablishing a healthy coastal ecosystem is to rebuild wetlands with river diversion or sediment conveyance projects that optimally manage and allocate sediments, minimally impact native flora and fauna, and positively affect the water quality. Engineering properties and material characteristics of the dredged material and foundation soils are input parameters in several mathematical models used to predict the long term behavior of the dredged material and foundation soil. Therefore, proper characterization of the dredged material and foundation soils is of utmost importance in the correct design of a coastal restoration and land reclamation project. The sedimentation and consolidation characteristics of the dredged material as well as their effects on the time rate of settlement of the suspended solid particles and underlying foundation soil depend, among other factors, on the (a) grain size distribution of the dredged material, (b) salinity (fresh, brackish, or saltwater environment) of the composite slurry, and (c) concentration of the solid particles in the slurry. This paper will present the results from column settling tests and self-weight consolidation tests performed on dredged samples obtained from actual restoration projects in Louisiana. The effects of salinity, grain size distribution, and initial particle concentration on the sedimentation and consolidation parameters of the dredged material will also be discussed.

Hurricane Maria Puerto Rico Landsat Analysis

DOE Data Explorer

Feng, Yanlei; Chambers, Jeff [LBNL; Negron-Juarez, Robinson [LBNL; Patricola, Chris; Clinton, Nick; Uriarte, Maria; Hall, Jaz; Collins, William

2018-01-01

Hurricane Maria made landfall as a strong Category 4 storm in southeast Puerto Rico on September 20th, 2018. The powerful storm traversed the island in a northwesterly direction causing widespread destruction. This study focused on a rapid assessment of Hurricane Marias impact to Puerto Ricos forests. Calibrated and corrected Landsat 8 image composites for the entire island were generated using Google Earth Engine for a comparable pre-Maria and post-Maria time period that accounted for phenology. Spectral mixture analysis (SMA) using image-derived end members was carried out on both composites to calculate the change in the non-photosynthetic vegetation (Delta-NPV) spectral response, a metric that quantifies the increased fraction of exposed wood and surface litter associated with tree mortality and crown damage from the storm. Hurricane simulations were also conducted using the Weather Research and Forecasting (WRF) regional climate model to estimate wind speeds associated with forest disturbance. Dramatic changes in forest structure across the entire island were evident from pre- and post-Maria composited Landsat 8 images. A Delta-NPV map for only the forested pixels illustrated significant spatial variability in disturbance, with patterns that associated with factors such as slope, aspect and elevation. An initial order-of-magnitude impact estimate based on previous work indicated that Hurricane Maria may have caused mortality and severe damage to 23-31 million trees. Additional field work and image analyses are required to further detail the impact of Hurricane Maria to Puerto Rico forests. A minor update to this dataset was posted on April 20, 2018. The previous version is being retired. If you need access to the prior version of the data, email ngee-tropics-archive@lbl.gov.

Revised paleoenvironmental analysis of the Holocene portion of the Barbados sea-level record: Cobbler's Reef revisited

NASA Astrophysics Data System (ADS)

Toscano, Marguerite A.

2016-06-01

Sample elevations corrected for tectonic uplift and assessed relative to local modeled sea levels provide a new perspective on paleoenvironmental history at Cobbler's Reef, Barbados. Previously, 14C-dated surface samples of fragmented Acropora palmata plotted above paleo sea level based on their present (uplifted) elevations, suggesting supratidal rubble deposited during a period of extreme storms (4500-3000 cal BP), precipitating reef demise. At several sites, however, A. palmata persisted, existing until ~370 cal BP. Uplift-corrected A. palmata sample elevations lie below the western Atlantic sea-level curve, and ~2 m below ICE-6G-modeled paleo sea level, under slow rates of sea-level rise, negating the possibility that Cobbler's Reef is a supratidal storm ridge. Most sites show limited age ranges from corals likely damaged/killed on the reef crest, not the mixed ages of rubble ridges, strongly suggesting the reef framework died off in stages over 6500 yr. Reef crest death assemblages invoke multiple paleohistoric causes, from ubiquitous hurricanes to anthropogenic impacts. Comparison of death assemblage ages to dated regional paleotempestological sequences, proxy-based paleotemperatures, recorded hurricanes, tsunamis, European settlement, deforestation, and resulting turbidity, reveals many possible factors inimical to the survival of A. palmata along Cobbler's Reef.

Ranking ICME's efficiency for geomagnetic and ionospheric storms and risk of false alarms

NASA Astrophysics Data System (ADS)

Gulyaeva, T. L.

2017-11-01

A statistical analysis is undertaken on ICME's efficiency in producing the geomagnetic and ionospheric storms. The mutually-consistent thresholds for the intense, moderate and weak space weather storms and quiet conditions are introduced with an analytical model based on relations between the equatorial Dst index and geomagnetic indices AE, aa, ap, ap(τ) and the ionospheric Vσ indices. The ionosphere variability Vσ index is expressed in terms of the total electron content (TEC) deviation from the -15-day sliding median normalized by the standard deviation for the 15 preceding days. The intensity of global positive ionospheric storm, Vσp, and negative storm, Vσn, is represented by the relative density of anomalous ±Vσ index occurrence derived from the global ionospheric maps GIM-TEC for 1999-2016. An impact of total 421 ICME events for 1999-2016 on the geomagnetic and ionospheric storms expressed by AE, Dst, aa, ap, ap(τ), Vσp, Vσn indices and their superposition is analyzed using ICME catalogue by Richardson and Cane (2010) during 24 h after the ICME start time t0. Hierarchy of efficiency of ICME → storm relation is established. The ICMEs have a higher probability (22-25%) to be followed by the intense ionospheric and auroral electrojet storms at global and high latitudes as compared to the intense storms at middle and low latitudes (18-20%) and to moderate and weak storms at high latitudes (5-17%). At the same time ICMEs are more effective in producing the moderate storms (24-28%) at the middle and low latitudes as compared to the intense and weak storms at these latitudes (13-22%) and to moderate storms at high latitudes (8-17%). The remaining cases when quiet conditions are observed after ICMEs present higher chance for a false alarm. The risk factor for a false alarm can vary from 18% if the superposition of all indices is considered, to 51-64% for individual AE, Vσp and Vσn indices. The analysis indicates that the mutually-consistent thresholds can be successfully applied to the external sources of the geomagnetic and ionospheric storms other than ICME which present challenge for the further investigation.

Mobility and safety impacts of winter storm events in a freeway environment.

DOT National Transportation Integrated Search

2000-02-01

Several factors influence a driver's decision to travel, choice of vehicle speed, and the safety of a particular trip. These factors include, among others, the trip purpose, time of day, traffic volumes, weather and roadway conditions, and the range ...

Plasma exchange in the treatment of thyroid storm secondary to type II amiodarone-induced thyrotoxicosis.

PubMed

Zhu, Ling; Zainudin, Sueziani Binte; Kaushik, Manish; Khor, Li Yan; Chng, Chiaw Ling

2016-01-01

Type II amiodarone-induced thyrotoxicosis (AIT) is an uncommon cause of thyroid storm. Due to the rarity of the condition, little is known about the role of plasma exchange in the treatment of severe AIT. A 56-year-old male presented with thyroid storm 2months following cessation of amiodarone. Despite conventional treatment, his condition deteriorated. He underwent two cycles of plasma exchange, which successfully controlled the severe hyperthyroidism. The thyroid hormone levels continued to fall up to 10h following plasma exchange. He subsequently underwent emergency total thyroidectomy and the histology of thyroid gland confirmed type II AIT. Management of thyroid storm secondary to type II AIT can be challenging as patients may not respond to conventional treatments, and thyroid storm may be more harmful in AIT patients owing to the underlying cardiac disease. If used appropriately, plasma exchange can effectively reduce circulating hormones, to allow stabilisation of patients in preparation for emergency thyroidectomy. Type II AIT is an uncommon cause of thyroid storm and may not respond well to conventional thyroid storm treatment.Prompt diagnosis and therapy are important, as patients may deteriorate rapidly.Plasma exchange can be used as an effective bridging therapy to emergency thyroidectomy.This case shows that in type II AIT, each cycle of plasma exchange can potentially lower free triiodothyronine levels for 10h.Important factors to consider when planning plasma exchange as a treatment for thyroid storm include timing of each session, type of exchange fluid to be used and timing of surgery.

Multifrequency analysis of a decametric storm observed at Voyager 1 and ground-based observatories

NASA Technical Reports Server (NTRS)

Maeda, K.; Carr, T. D.

1989-01-01

Observations of a Jovian decametric non-Io-A noise storm made from Voyager 1, the University of Florida Radio Observatory, the University of Texas Radio Astronomy Observatory, and the Jupiter station at Goddard Space Flight Center at frequencies of 26.3, 22.2, 20.0, and 18.0 MHz were found to be correlated. The activity observed at the ground stations occurred 68 min after the corresponding activity at Voyager 1. After correction is made for propagation time differences, this delay is reduced to 34 min. It is demonstrated that at each frequency the envelope of the individual-event beams occurring during the storm (some or all of which are associated with dynamic spectral arcs) is a quasi-constant structure that corotates with the inner Jovian magnetosphere, and that the width of this envelope beam is frequency dependent. The width increases as frequency is decreased, mainly because of the change in position of the trailing-edge beam boundary. Evidence for a relatively slow temporal change in beam geometry is also presented.

Thyroid Storm in a Patient with Trauma - A Challenging Diagnosis for the Emergency Physician: Case Report and Literature Review.

PubMed

Wang, Hsiang-I; Yiang, Giou-Teng; Hsu, Chin-Wang; Wang, Jen-Chun; Lee, Chien-Hsing; Chen, Yu-Long

2017-03-01

Thyroid storm, an endocrine emergency, remains a diagnostic and therapeutic challenge. It is recognized to develop as a result of several factors, including infection, surgery, acute illness, and rarely, trauma. Recognition of thyroid storm in a trauma patient is difficult because the emergency physician usually focuses on managing more obvious injuries. We present a case of trauma-related thyroid storm and review the previous literature on posttraumatic thyroid storm to delineate risk factors of the disease. The case occurred in a 32-year-old man after a motorcycle accident. Careful investigation of patient history and risk factors of trauma-related thyroid storms and utilization of the scoring system may facilitate early diagnosis. Traumatically induced thyroid storm usually responds to medical treatment developed for hyperthyroidism. Surgical intervention may be needed for patients who failed medical treatment or those with direct thyroid gland injuries. The outcome is usually fair under appropriate management. We present a case of trauma-related thyroid storm to illustrate the diagnostic and therapeutic approach with a summary of the previous literature. Emergency physicians should be aware of the clinical presentation and risk factors of patients with trauma-related thyroid storm to reduce the rate of misdiagnosis and prevent catastrophic outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessment of spill flow emissions on the basis of measured precipitation and waste water data

NASA Astrophysics Data System (ADS)

Hochedlinger, Martin; Gruber, Günter; Kainz, Harald

2005-09-01

Combined sewer overflows (CSOs) are substantial contributors to the total emissions into surface water bodies. The emitted pollution results from dry-weather waste water loads, surface runoff pollution and from the remobilisation of sewer deposits and sewer slime during storm events. One possibility to estimate overflow loads is a calculation with load quantification models. Input data for these models are pollution concentrations, e.g. Total Chemical Oxygen Demand (COD tot), Total Suspended Solids (TSS) or Soluble Chemical Oxygen Demand (COD sol), rainfall series and flow measurements for model calibration and validation. It is important for the result of overflow loads to model with reliable input data, otherwise this inevitably leads to bad results. In this paper the correction of precipitation measurements and the sewer online-measurements are presented to satisfy the load quantification model requirements already described. The main focus is on tipping bucket gauge measurements and their corrections. The results evidence the importance of their corrections due the effects on load quantification modelling and show the difference between corrected and not corrected data of storm events with high rain intensities.

Spatio-temporal modelling of wind speed variations and extremes in the Caribbean and the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Rychlik, Igor; Mao, Wengang

2018-02-01

The wind speed variability in the North Atlantic has been successfully modelled using a spatio-temporal transformed Gaussian field. However, this type of model does not correctly describe the extreme wind speeds attributed to tropical storms and hurricanes. In this study, the transformed Gaussian model is further developed to include the occurrence of severe storms. In this new model, random components are added to the transformed Gaussian field to model rare events with extreme wind speeds. The resulting random field is locally stationary and homogeneous. The localized dependence structure is described by time- and space-dependent parameters. The parameters have a natural physical interpretation. To exemplify its application, the model is fitted to the ECMWF ERA-Interim reanalysis data set. The model is applied to compute long-term wind speed distributions and return values, e.g., 100- or 1000-year extreme wind speeds, and to simulate random wind speed time series at a fixed location or spatio-temporal wind fields around that location.

Geomagnetic storms can trigger stroke: evidence from 6 large population-based studies in Europe and Australasia.

PubMed

Feigin, Valery L; Parmar, Priya G; Barker-Collo, Suzanne; Bennett, Derrick A; Anderson, Craig S; Thrift, Amanda G; Stegmayr, Birgitta; Rothwell, Peter M; Giroud, Maurice; Bejot, Yannick; Carvil, Phillip; Krishnamurthi, Rita; Kasabov, Nikola

2014-06-01

Although the research linking cardiovascular disorders to geomagnetic activity is accumulating, robust evidence for the impact of geomagnetic activity on stroke occurrence is limited and controversial. We used a time-stratified case-crossover study design to analyze individual participant and daily geomagnetic activity (as measured by Ap Index) data from several large population-based stroke incidence studies (with information on 11 453 patients with stroke collected during 16 031 764 person-years of observation) in New Zealand, Australia, United Kingdom, France, and Sweden conducted between 1981 and 2004. Hazard ratios and corresponding 95% confidence intervals (CIs) were calculated. Overall, geomagnetic storms (Ap Index 60+) were associated with 19% increase in the risk of stroke occurrence (95% CI, 11%-27%). The triggering effect of geomagnetic storms was most evident across the combined group of all strokes in those aged <65 years, increasing stroke risk by >50%: moderate geomagnetic storms (60-99 Ap Index) were associated with a 27% (95% CI, 8%-48%) increased risk of stroke occurrence, strong geomagnetic storms (100-149 Ap Index) with a 52% (95% CI, 19%-92%) increased risk, and severe/extreme geomagnetic storms (Ap Index 150+) with a 52% (95% CI, 19%-94%) increased risk (test for trend, P<2×10(-16)). Geomagnetic storms are associated with increased risk of stroke and should be considered along with other established risk factors. Our findings provide a framework to advance stroke prevention through future investigation of the contribution of geomagnetic factors to the risk of stroke occurrence and pathogenesis. © 2014 American Heart Association, Inc.

The analysis of dependence between extreme rainfall and storm surge in the coastal zone

NASA Astrophysics Data System (ADS)

Zheng, F.; Westra, S.

2012-12-01

Flooding in coastal catchments can be caused by runoff generated by an extreme rainfall event, elevated sea levels due to an extreme storm surge event, or the combination of both processes occurring simultaneously or in close succession. Dependence in extreme rainfall and storm surge arises because common meteorological forcings often drive both variables; for example, cyclonic systems may produce extreme rainfall, strong onshore winds and an inverse barometric effect simultaneously, which the former factor influencing catchment discharge and the latter two factors influencing storm surge. Nevertheless there is also the possibility that only one of the variables is extreme at any given time, so that the dependence between rainfall and storm surge is not perfect. Quantification of the strength of dependence between these processes is critical in evaluating the magnitude of flood risk in the coastal zone. This may become more important in the future as the majority of the coastal areas are threatened by the sea level rise due to the climate change. This research uses the most comprehensive record of rainfall and storm surge along the coastline of Australia collected to-date to investigate the strength of dependence between the extreme rainfall and storm surge along the Australia coastline. A bivariate logistic threshold-excess model was employed to this end to carry out the dependence analysis. The strength of the estimated dependence is then evaluated as a function of several factors including: the distance between the tidal gauge and the rain gauge; the lag between the extreme precipitation event and extreme surge event; and the duration of the maximum storm burst. The results show that the dependence between the extreme rainfall and storm surge along the Australia coastline is statistically significant, although some locations clearly exhibit stronger dependence than others. We hypothesize that this is due to a combination of large-scale meteorological effects as well as local scale bathymetry. Additionally, significant dependence can be observed over spatial distances of up to several hundred kilometers, implying that meso-scale meteorological forcings may play an important role in driving the dependence. This is also consistent with the result which shows that significant dependence often remaining for lags of up to one or two days between extremal rainfall and storm surge events. The influence of storm burst duration can also be observed, with rainfall extremes lasting more than several hours typically being more closely associated with storm surge compared with sub-hourly rainfall extremes. These results will have profound implications for how flood risk is evaluated along the coastal zone in Australia, with the strength of dependence varying depending on: (1) the dominant meteorological conditions; (2) the local estuary configuration, influencing the strength of the surge; and (3) the catchment attributes, influencing the duration of the storm burst that will deliver the peak flood events. Although a strong random component remains, we show that the probability of an extreme storm surge during an extreme rainfall event (or vice versa) can be up to ten times greater than under the situation under which there is no dependence, suggesting that failure to account for these interactions can result in a substantial underestimation of flood risk.

Beyond the Storm: Comparison of Clinical Factors, Arrhythmogenic Substrate, and Catheter Ablation Outcomes in Structural Heart Disease Patients With versus Those Without a History of Ventricular Tachycardia Storm.

PubMed

Kumar, Saurabh; Fujii, Akira; Kapur, Sunil; Romero, Jorge; Mehta, Nishaki K; Tanigawa, Shinichi; Epstein, Laurence M; Koplan, Bruce A; Michaud, Gregory F; John, Roy M; Stevenson, William G; Tedrow, Usha B

2017-01-01

Catheter ablation can be lifesaving in ventricular tachycardia (VT) storm, but the underlying substrate in patients with storm is not well characterized. We sought to compare the clinical factors, substrate, and outcomes differences in patients with sustained monomorphic VT who present for catheter ablation with VT storm versus those with a nonstorm presentation. Consecutive ischemic (ICM; n = 554) or nonischemic cardiomyopathy patients (NICM; n = 369) with a storm versus nonstorm presentation were studied (ICM storm 186; NICM storm 101). In ICM, storm compared with nonstorm patients had significantly lower left ventricular (LV) ejection fraction (EF), greater number of antiarrhythmic drug (AAD) failures, slower VTs, greater number of scarred LV segments, higher incidence of anterior, septal, and apical endocardial LV scar (all P < 0.05). However, outcomes in follow-up were similar (12-month ventricular arrhythmia [VA]-free survival: 51% vs. 52%, P = 0.6; survival free of death/transplant 75% vs. 87%, P = 0.7). In addition to the above differences, NICM storm patients were also older; however, the extent and distribution of scar was similar except for a higher incidence of lateral endocardial scar in storm patients (P = 0.05). VA-free survival (36% vs. 47%, P = 0.004) and survival free of death/transplant, however, were worse in NICM storm than nonstorm patients (72% vs. 88%, P = 0.001). NICM storm patients had worse VA-free survival than ICM storm patients. There are differences in clinical factors and scar patterns in patients undergoing VT ablation who present with VT storm versus those with a nonstorm presentation. Clinical outcomes are worse in NICM storm patients. © 2016 Wiley Periodicals, Inc.

Statistical characteristics of storm interevent time, depth, and duration for eastern New Mexico, Oklahoma, and Texas

USGS Publications Warehouse

Asquith, William H.; Roussel, Meghan C.; Cleveland, Theodore G.; Fang, Xing; Thompson, David B.

2006-01-01

The design of small runoff-control structures, from simple floodwater-detention basins to sophisticated best-management practices, requires the statistical characterization of rainfall as a basis for cost-effective, risk-mitigated, hydrologic engineering design. The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, has developed a framework to estimate storm statistics including storm interevent times, distributions of storm depths, and distributions of storm durations for eastern New Mexico, Oklahoma, and Texas. The analysis is based on hourly rainfall recorded by the National Weather Service. The database contains more than 155 million hourly values from 774 stations in the study area. Seven sets of maps depicting ranges of mean storm interevent time, mean storm depth, and mean storm duration, by county, as well as tables listing each of those statistics, by county, were developed. The mean storm interevent time is used in probabilistic models to assess the frequency distribution of storms. The Poisson distribution is suggested to model the distribution of storm occurrence, and the exponential distribution is suggested to model the distribution of storm interevent times. The four-parameter kappa distribution is judged as an appropriate distribution for modeling the distribution of both storm depth and storm duration. Preference for the kappa distribution is based on interpretation of L-moment diagrams. Parameter estimates for the kappa distributions are provided. Separate dimensionless frequency curves for storm depth and duration are defined for eastern New Mexico, Oklahoma, and Texas. Dimension is restored by multiplying curve ordinates by the mean storm depth or mean storm duration to produce quantile functions of storm depth and duration. Minimum interevent time and location have slight influence on the scale and shape of the dimensionless frequency curves. Ten example problems and solutions to possible applications are provided.

NPDES Permit for Federal Corrections Institution, Englewood Municipal Separate Storm Sewer System in Colorado

EPA Pesticide Factsheets

Under NPDES permit CO-R042005, the Federal Corrections Institution (FCI), Englewood is authorized to discharge from all MS4 outfalls to receiving waters which include Bear Creek, the South Platte River in the City of Lakewood, Jefferson County, Colo.

Climate and on-farm risk factors associated with Giardia duodenalis cysts in storm runoff from California coastal dairies.

PubMed

Miller, Woutrina A; Lewis, David J; Lennox, Michael; Pereira, Maria G C; Tate, Kenneth W; Conrad, Patricia A; Atwill, Edward R

2007-11-01

Climatic factors and on-farm management practices were evaluated for their association with the concentrations (cyst/liter) and instantaneous loads (cysts/second) of Giardia duodenalis in storm-based runoff from dairy lots and other high-cattle-use areas on five coastal California farms over two storm seasons. Direct fluorescent antibody analysis was used to quantitate cysts in 350 storm runoff samples. G. duodenalis was detected on all five dairy farms, with fluxes of 1 to 14,000 cysts/liter observed in 16% of samples. Cysts were detected in 41% of runoff samples collected near cattle less than 2 months old, compared to 10% of runoff samples collected near cattle over 6 months old. Furthermore, the concentrations and instantaneous loads of cysts were > or =65 and > or =79 times greater, respectively, in runoff from sites housing young calves than in sites housing other age classes of animals. Factors associated with environmental loading of G. duodenalis included cattle age, cattle stocking number, and precipitation but not lot area, land slope, or cattle density. Vegetated buffer strips were found to significantly reduce waterborne cysts in storm runoff: each additional meter of vegetated buffer placed below high-cattle-use areas was associated with reductions in the concentration and instantaneous load of cysts by factors of 0.86 and 0.79 (-0.07 and -0.10 log(10)/m), respectively. Straw mulch, seed application, scraping of manure, and cattle exclusion did not significantly affect the concentration or load of G. duodenalis cysts. The study findings suggest that vegetated buffer strips, especially when placed near dairy calf areas, should help reduce the environmental loading of these fecal protozoa discharging from dairy farms.

Use of Remote Sensing Data to Enhance NWS Storm Damage Toolkit

NASA Technical Reports Server (NTRS)

Jedlove, Gary J.; Molthan, Andrew L.; White, Kris; Burks, Jason; Stellman, Keith; Smith, Mathew

2012-01-01

In the wake of a natural disaster such as a tornado, the National Weather Service (NWS) is required to provide a very detailed and timely storm damage assessment to local, state and federal homeland security officials. The Post ]Storm Data Acquisition (PSDA) procedure involves the acquisition and assembly of highly perishable data necessary for accurate post ]event analysis and potential integration into a geographic information system (GIS) available to its end users and associated decision makers. Information gained from the process also enables the NWS to increase its knowledge of extreme events, learn how to better use existing equipment, improve NWS warning programs, and provide accurate storm intensity and damage information to the news media and academia. To help collect and manage all of this information, forecasters in NWS Southern Region are currently developing a Storm Damage Assessment Toolkit (SDAT), which incorporates GIS ]capable phones and laptops into the PSDA process by tagging damage photography, location, and storm damage details with GPS coordinates for aggregation within the GIS database. However, this tool alone does not fully integrate radar and ground based storm damage reports nor does it help to identify undetected storm damage regions. In many cases, information on storm damage location (beginning and ending points, swath width, etc.) from ground surveys is incomplete or difficult to obtain. Geographic factors (terrain and limited roads in rural areas), manpower limitations, and other logistical constraints often prevent the gathering of a comprehensive picture of tornado or hail damage, and may allow damage regions to go undetected. Molthan et al. (2011) have shown that high resolution satellite data can provide additional valuable information on storm damage tracks to augment this database. This paper presents initial development to integrate satellitederived damage track information into the SDAT for near real ]time use by forecasters and decision makers.

Use of Remote Sensing Data to Enhance NWS Storm Damage Toolkit

NASA Astrophysics Data System (ADS)

Jedlovec, G.; Molthan, A.; White, K.; Burks, J.; Stellman, K.; Smith, M. R.

2012-12-01

In the wake of a natural disaster such as a tornado, the National Weather Service (NWS) is required to provide a very detailed and timely storm damage assessment to local, state and federal homeland security officials. The Post-Storm Data Acquisition (PSDA) procedure involves the acquisition and assembly of highly perishable data necessary for accurate post-event analysis and potential integration into a geographic information system (GIS) available to its end users and associated decision makers. Information gained from the process also enables the NWS to increase its knowledge of extreme events, learn how to better use existing equipment, improve NWS warning programs, and provide accurate storm intensity and damage information to the news media and academia. To help collect and manage all of this information, forecasters in NWS Southern Region are currently developing a Storm Damage Assessment Toolkit (SDAT), which incorporates GIS-capable phones and laptops into the PSDA process by tagging damage photography, location, and storm damage details with GPS coordinates for aggregation within the GIS database. However, this tool alone does not fully integrate radar and ground based storm damage reports nor does it help to identify undetected storm damage regions. In many cases, information on storm damage location (beginning and ending points, swath width, etc.) from ground surveys is incomplete or difficult to obtain. Geographic factors (terrain and limited roads in rural areas), manpower limitations, and other logistical constraints often prevent the gathering of a comprehensive picture of tornado or hail damage, and may allow damage regions to go undetected. Molthan et al. (2011) have shown that high resolution satellite data can provide additional valuable information on storm damage tracks to augment this database. This paper presents initial development to integrate satellite-derived damage track information into the SDAT for near real-time use by forecasters and decision makers.

Analysis of fecal coliform levels at selected storm water monitoring points at the Oak Ridge Y-12 Plant

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

Skaggs, B.E.

1995-07-01

The Environmental Protection Agency staff published the final storm water regulation on November 16, 1990. The storm water regulation is included in the National Pollutant Discharge Elimination System (NPDES) regulations. It specifies the permit application requirements for certain storm water discharges such as industrial activity or municipal separate storm sewers serving populations of 100,000 or greater. Storm water discharge associated with industrial activity is discharge from any conveyance used for collecting and conveying storm water that is directly related to manufacturing, processing, or raw material storage areas at an industrial plant. Quantitative testing data is required for these discharges. Anmore » individual storm water permit application was completed and submitted to Tennessee Department of Environment and Conservation (TDEC) personnel in October 1992. After reviewing this data in the permit application, TDEC personnel expressed concern with the fecal coliform levels at many of the outfalls. The 1995 NPDES Permit (Part 111-N, page 44) requires that an investigation be conducted to determine the validity of this data. If the fecal coliform data is valid, the permit requires that a report be submitted indicating possible causes and proposed corrective actions.« less

Calibration of GOES-VISSR, visible-band satellite data and its application to the analysis of a dust storm at Owens Lake, California

USGS Publications Warehouse

MacKinnon, D.J.; Chavez, P.S.; Fraser, R. S.; Niemeyer, T.C.; Gillette, Dale A.

1996-01-01

As part of a joint Russian/American dust-storm experiment, GOES-VISSR (Geostationary Operational Environmental Satellite, Visible-Infrared Spin-Scan Radiometer), data from a visible-band satellite image of a large dust storm emanating from Owens Lake, California were acquired on March 10 and 11, 1993. The satellite data were calibrated to targets of known ground reflectance factors and processed with radiative transfer techniques to yield aerosol (dust) optical depth at those stages of the dust storm when concurrent ground-based measurements of optical depth were made. Calibration of the satellite data is crucial for comparing surficial changes in remotely sensed data acquired over a period of time from the same area and for determining accurate concentrations of atmospheric aerosols using radiative transfer techniques. The calibration procedure forces the distribution of visible-band, DN (digital number) values, acquired on July 1, 1992, at 1731 GMT from the GOES-VISSR sensor over a large test area, to match the distribution of visible-band, DN values concurrently acquired from a Landsat MSS (Multispectral Scanner) sensor over the same test area; the Landsat MSS DN values were directly associated with reflectance factors measured from ground targets. The calibrated GOES-VISSR data for July 1, 1992, were then used to calibrate other GOES-VISSR data acquired on March 10 and 11, 1993, during the dust storm. Uncertainties in location of ground targets, bi-directional reflectance and atmospheric attenuation contribute an error of approximately ??0.02 in the satellite-inferred ground reflectance factors. On March 11 at 1031 PST the satellite-received radiances during the peak of the storm were 3 times larger than predicted by our radiative transfer model for a pure clay dust plume of infinite optical depth. This result supported ground-based measurements that the plume at that time was composed primarily of large salt grains, probably sodium sulfate, which could not be properly characterized in our radiative transfer model. Further, the satellite data showed that the salt fell out of the plume within 35 km from the source. Finer-grained, clay dust was observed to extend beyond the salt-laden plume and was the major component of the dust plume after 1131 PST, when erosion of the salt crust on Owens Lake ceased. By 1331 and 1401 PST satellite-inferred, optical depths compared favorably with measurements concurrently acquired at the ground. Uncertainties in bi-directional reflectance, atmospheric attenuation, and locating ground points in the satellite data manifest errors between the inferred and measured optical depths in the range of 20 to 50%; these errors would be much greater without the calibration of the GOES-VISSR data. Changes in satellite-inferred reflectance factors over the lake bed during the course of the storm showed that 76 km2 of the surface was disrupted during the March 11 storm, suggesting as much as 76 ?? 103 m3 of crustal material were displaced for each millimeter of several estimated to have been moved during the storm; an unknown fraction of the displaced material was suspended. The satellite data also showed dust fallout on mountain snowfields. Whereas fallout may have removed most of the salt, satellite data acquired at 1631 PST, when the plume had a large brightness contrast with the ground, showed that it covered over 2500 km2 and contained at least 1.6 ?? 109 g of sediment. For such a small source area, the dust represents a substantial contribution to the regional and global load of aerosols.

Storm surge along the Pacific coast of North America

NASA Astrophysics Data System (ADS)

Bromirski, Peter D.; Flick, Reinhard E.; Miller, Arthur J.

2017-01-01

Storm surge is an important factor that contributes to coastal flooding and erosion. Storm surge magnitude along eastern North Pacific coasts results primarily from low sea level pressure (SLP). Thus, coastal regions where high surge occurs identify the dominant locations where intense storms make landfall, controlled by storm track across the North Pacific. Here storm surge variability along the Pacific coast of North America is characterized by positive nontide residuals at a network of tide gauge stations from southern California to Alaska. The magnitudes of mean and extreme storm surge generally increase from south to north, with typically high amplitude surge north of Cape Mendocino and lower surge to the south. Correlation of mode 1 nontide principal component (PC1) during winter months (December-February) with anomalous SLP over the northeast Pacific indicates that the dominant storm landfall region is along the Cascadia/British Columbia coast. Although empirical orthogonal function spatial patterns show substantial interannual variability, similar correlation patterns of nontide PC1 over the 1948-1975 and 1983-2014 epochs with anomalous SLP suggest that, when considering decadal-scale time periods, storm surge and associated tracks have generally not changed appreciably since 1948. Nontide PC1 is well correlated with PC1 of both anomalous SLP and modeled wave height near the tide gauge stations, reflecting the interrelationship between storms, surge, and waves. Weaker surge south of Cape Mendocino during the 2015-2016 El Niño compared with 1982-1983 may result from changes in Hadley circulation. Importantly from a coastal impacts perspective, extreme storm surge events are often accompanied by high waves.

North-south asymmetric thermosphere response to geomagnetic storms caused by coronal mass ejections

NASA Astrophysics Data System (ADS)

Oliveira, D. M.; Zesta, E.; Schuck, P. W.; Sutton, E. K.

2017-12-01

We use CHAMP and GRACE density data in a statistical and superposed epoch analysis study to investigate the thermosphere global space and time response to CME-caused geomagnetic storms in the time period of September 2001 to September 2011. In order to account for solar cycle effects, we inter-calibrate both CHAMP and GRACE data against the Jacchia-Bowman 2008 (JB2008) empirical model under a regime of very low geomagnetic activity by fitting a polynomial fit with orthogonal expansion into the modeled density. We choose two different approaches related to physical effects of CME interactions with the magnetosphere. The zero epoch times are chosen as follows: in the first case, the instance of CME impact time associated with compression effects and, in the second case, the instance of time in which the IMF Bz turns suddenly southward, associated with the storm main phase onset. In general, in the second case, the thermosphere effects are more superposed in time in comparison to the effects of the first case. We find that, on average, large scale wave structures, presumably traveling atmospheric disturbances (TADs), propagate from auroral to equatorial regions in lag times as short as 3 hours. We also find that all local time regions, i.e., the global response, takes 2 more hours to occur. In addition, our findings show that there exists a strong north-south asymmetric heating, being most pronounced in the Southern Hemisphere in the moments preceding and following the zero epoch time. We attribute this effect to a combination of several factors that affect high latitude energy input into the upper atmosphere, such as seasons, IMF By component, and universal times, that is, the dipole longitude position during the developing of the storm main phase, the crucial time for energy input and subsequent thermosphere heating during geomagnetic storms.

2016 Resembles Past Global Dust Storm Years on Mars

NASA Image and Video Library

2016-10-05

This graphic indicates a similarity between 2016 (dark blue line) and five past years in which Mars has experienced a global dust storm (orange lines and band), compared to years with no global dust storm (blue-green lines and band). The arrow nearly midway across in the dark blue line indicates the Mars time of year in late September 2016. A key factor in the graph is the orbital angular momentum of Mars, which would be steady in a system of only one planet orbiting the sun, but varies due to relatively small effects of having other planets in the solar system. The horizontal scale is time of year on Mars, starting at left with the planet's farthest distance from the sun in each orbit. This point in the Mars year, called "Mars aphelion," corresponds to late autumn in the southern hemisphere. Numeric values on the horizontal axis are in Earth years; each Mars year lasts for about 1.9 Earth years. The vertical scale bar at left applies only to the black-line curve on the graph. The amount of solar energy entering Mars' atmosphere (in watts per square meter) peaks at the time of year when Mars is closest to the sun, corresponding to late spring in the southern hemisphere. The duration of Mars' dust storm season, as indicated, brackets the time of maximum solar input to the atmosphere. The scale bar at right, for orbital angular momentum, applies to the blue, brown and blue-green curves on the graph. The values are based on mass, velocity and distance from the gravitational center of the solar system. Additional information on the units is in a 2015 paper in the journal Icarus, from which this graph is derived. The band shaded in orange is superimposed on the curves of angular momentum for five Mars years that were accompanied by global dust storms in 1956, 1971, 1982, 1994 and 2007. Brown diamond symbols on the curves for these years in indicate the times when the global storms began. The band shaded blue-green lies atop angular momentum curves for six years when no global dust storms occurred: 1939, 1975, 1988, 1998, 2000 and 2011. Note that in 2016, as in the pattern of curves for years with global dust storms, the start of the dust storm season corresponded to a period of increasing orbital angular momentum. In years with no global storm, angular momentum was declining at that point. Observations of whether dust from regional storms on Mars spreads globally in late 2016 or early 2017 will determine whether this correspondence holds up for the current Mars year. http://photojournal.jpl.nasa.gov/catalog/PIA20855

Long space missions, gene therapy, and the vital role of magnesium: a three-pronged plan for the next 50 years

PubMed Central

Rowe, William J

2010-01-01

Since pharmaceuticals cannot be used in space until liver and kidney dysfunctions are corrected, and with invariable malabsorption, it appears there is no alternative other than to use subcutaneous magnesium (Mg) replacements in the presence of deficiencies and use of gene therapy. I suggest beginning with the correction of as many as four gene deficiencies: atrial natriuretic peptide (ANP), nitric oxide (NO), vascular endothelial growth factor (VEGF), and erythropoietin (EPO), all as well as Mg related to perfusion and angiogenesis. There is no evidence of significant lunar radiation levels in the absence of a solar storm. It could then be determined whether this has resulted in correction of liver and kidney dysfunction. If this persists, serial additions of gene therapy will be required determining the effect of each individual gene trial on organ function. Microgravity and endothelial gaps with leaks trigger reduced plasma volume. Partial correction by use of a plasma volume substitute and development of a delivery device may reduce complexity of gene therapy. Research would be conducted both on Earth and in microgravity, with the development of subcutaneous pharmaceuticals and Mg, and a space walk-reliable subcutaneous silicon device, given that no replenishable subcutaneous device is presently available. A three-pronged approach provides a plan for the next 50 years: A. complete correction of a Mg deficit; B. partial replacement with plasma volume substitutes, and C. multiple gene factor strategy. PMID:21694938

Long space missions, gene therapy, and the vital role of magnesium: a three-pronged plan for the next 50 years.

PubMed

Rowe, William J

2010-01-01

Since pharmaceuticals cannot be used in space until liver and kidney dysfunctions are corrected, and with invariable malabsorption, it appears there is no alternative other than to use subcutaneous magnesium (Mg) replacements in the presence of deficiencies and use of gene therapy. I suggest beginning with the correction of as many as four gene deficiencies: atrial natriuretic peptide (ANP), nitric oxide (NO), vascular endothelial growth factor (VEGF), and erythropoietin (EPO), all as well as Mg related to perfusion and angiogenesis. There is no evidence of significant lunar radiation levels in the absence of a solar storm. It could then be determined whether this has resulted in correction of liver and kidney dysfunction. If this persists, serial additions of gene therapy will be required determining the effect of each individual gene trial on organ function. Microgravity and endothelial gaps with leaks trigger reduced plasma volume. Partial correction by use of a plasma volume substitute and development of a delivery device may reduce complexity of gene therapy. Research would be conducted both on Earth and in microgravity, with the development of subcutaneous pharmaceuticals and Mg, and a space walk-reliable subcutaneous silicon device, given that no replenishable subcutaneous device is presently available. A three-pronged approach provides a plan for the next 50 years: A. complete correction of a Mg deficit; B. partial replacement with plasma volume substitutes, and C. multiple gene factor strategy. 2010 Halvorson et al, publisher and licensee Dove Medical Press Ltd.

Characterization of within-day beginning times of storms for stochastic simulation

USDA-ARS?s Scientific Manuscript database

The beginning times of storms within a day are often required for stochastic modeling purposes and for studies on plant growth. This study investigated the variation in frequency distributions of storm-initiation time (SI time) within a day due to elevation changes and month. Actual storms without 2...

Global ionospheric dynamics and electrodynamics during geomagnetic storms (Invited)

NASA Astrophysics Data System (ADS)

Mannucci, A. J.; Tsurutani, B.; Verkhoglyadova, O. P.; Komjathy, A.; Butala, M. D.

2013-12-01

Globally distributed total electron content (TEC) data has become an important tool for exploring the consequences of storm-time electrodynamics. Magnetosphere-ionosphere coupling during the main phase is responsible for the largest ionospheric effects observed during geomagnetic storms, mediated by global scale electrodynamics. Recent research using case studies reveals a complex picture of M-I coupling and its relationship to interplanetary drivers such as the solar wind electric field. Periods of direct coupling exist where the solar wind electric field is strongly correlated with prompt penetration electric fields, observed as enhanced vertical plasma drifts or an enhanced electrojet in the daytime equatorial ionosphere. Periods of decoupling between low latitude electric fields and the solar wind electric field are also observed, but the factors distinguishing these two types of response have not been clearly identified. Recent studies during superstorms suggest a role for the transverse (y-component) of the interplanetary magnetic field, which affects magnetospheric current systems and therefore may affect M-I coupling, with significant ionospheric consequences. Observations of the global ionospheric response to a range of geomagnetic storm intensities are presented. Scientific understanding of the different factors that affect electrodynamic aspects of M-I coupling are discussed.

Identification of independent storm events: Seasonal and spatial variability of times between storms in Alpine area

NASA Astrophysics Data System (ADS)

Iadanzaa, Carla; Rianna, Maura; Orlando, Dario; Ubertini, Lucio; Napolitano, Francesco

2013-10-01

The aim of the paper is the identification of rain events that trigger landslides through the use of an exponential method to separate stochastic independent events. This activity is carried out within the definition of empirical rainfall thresholds for debris flows and shallow landslides. The study area is the Trento district, which is located in the northeast zone of an Alpine area. The work evaluates the factors that affect the variability in space and time of the critical duration of each rain gauge, defined as the minimum dry period duration that separates two rainy periods that are stochastically independent.

Cyclone Xaver seen by SARAL/AltiKa

NASA Astrophysics Data System (ADS)

Scharroo, Remko; Fenoglio, Luciana; Annunziato, Alessandro

2014-05-01

During the first week of December 2013, Cyclone Xaver pounded the coasts and the North Sea. On 6 December, all along the Wadden Sea, the barrier islands along the north of the Netherlands and the northwest of Germany experienced record storm surges. We show a comparison of the storm surge measured by the radar altimeter AltiKa on-board the SARAL satellite and various types of in-situ data and models. Two tide gauges along the German North Sea coast, one in the southern harbour of the island of Helgoland and one on an offshore lighthouse Alte Weser, confirmed that the storm drove sea level to about three meters above the normal tide level. Loading effects during the storm are also detected by the GPS measurements at several tide gauge stations. The altimeter in the mean time shows that the storm surge was noticeable as far as 400 km from the coast. The altimeter measured wind speeds of 20 m/s nearly monotonically throughout the North Sea. An offshore anemometer near the island of Borkum corroborated this value. A buoy near the FINO1 offshore platform measured wave heights of 8 m, matching quite well the measurements from the altimeter, ranging from 6 m near the German coast to 12 m further out into the North Sea. Furthermore we compare the altimeter-derived and in-situ sea level, wave height and wind speed products with outputs from the Operation Circulation and Forecast model of the Bundesamt für Seeschifffahrt und Hydrographie (BSH) and with a global storm surge forecast and inundation model of the Joint Research Centre (JRC) of the European Commission. The Operational circulation model of BSH (BSHcmod) and its component, the surge model (BSHsmod), perform daily predictions for the next 72 hours based on the meteorological model of the Deutsche Wetterdienst (DWD). The JRC Storm Surge Calculation System is a new development that has been established at the JRC in the framework of the Global Disasters Alerts and Coordination System (GDACS). The system uses meteorological forecasts produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) to estimate (with a 2-day lead time) potential storm surges due to cyclone or general storm events. Departure between model and altimeter-derived values, in particularly wind, are investigated and discussed. The qualitative agreement is satisfactory; the maximum storm surge peak is correctly estimated by BSH but underestimated by JRC due to insufficient wind forcing. The wind speed of SARAL/AltiKa agrees well with the ECMWF model wind speed but is lower than the DWD model estimate. The authors acknowledge the kind support from the BSH, the Bundesumweltministerium (BMU), Projectträger Jülich (PTJ), and the Wasser- und Schifffahrtsverwaltung des Bundes (WSV).

X-Band Radar for Studies of Tropical Storms from High Altitude UAV Platform

NASA Technical Reports Server (NTRS)

Rodriquez, Shannon; Heymsfield, Gerald; Li, Lihua; Bradley, Damon

2007-01-01

The increased role of unmanned aerial vehicles (UAV) in NASA's suborbital program has created a strong interest in the development of instruments with new capabilities, more compact sizes and reduced weights than the instruments currently operated on manned aircrafts. There is a strong demand and tremendous potential for using high altitude UAV (HUAV) to carry weather radars for measurements of reflectivity and wind fields from tropical storms. Tropical storm genesis frequently occurs in ocean regions that are inaccessible to piloted aircraft due to the long off shore range and the required periods of time to gather significant data. Important factors of interest for the study of hurricane genesis include surface winds, profiled winds, sea surface temperatures, precipitation, and boundary layer conditions. Current satellite precipitation and surface wind sensors have resolutions that are too large and revisit times that are too infrequent to study this problem. Furthermore, none of the spaceborne sensors measure winds within the storm itself. A dual beam X-band Doppler radar, UAV Radar (URAD), is under development at the NASA Goddard Space Flight Center for the study of tropical storms from HUAV platforms, such as a Global Hawk. X-band is the most desirable frequency for airborne weather radars since these can be built in a relatively compact size using off-the-shelf components which cost significantly less than other higher frequency radars. Furthermore, X-band radars provide good sensitivity with tolerable attenuation in storms. The low-cost and light-weight URAD will provide new capabilities for studying hurricane genesis by analyzing the vertical structure of tropical cyclones as well as 3D reflectivity and wind fields in clouds. It will enable us to measure both the 3D precipitation structure and surface winds by using two antenna beams: fixed nadir and conical scanning each produced by its associated subsystem. The nadir subsystem is a magnetron based radar modified from a marine radar transceiver. It is capable of measuring vertical reflectivity and velocity profile while being a lower-cost, smaller size, and lighter weight version of the NASA ER-2 Doppler Radar (EDOP), which has flown during many NASA field campaigns and has provided valuable scientific information on hurricanes and weather phenomena. Unfortunately, EDOP is too large and heavy for most UAV platforms, but the experience gained with this instrument provided us with the heritage to build a new low-cost, light-weight, smaller system that will be capable of flying on UAVs. The scanning subsystem uses a TWT transmitter and provides measurements of 3D reflectivity/wind fields in-clouds. Conical scanning of the radar beam at a 35 deg. incidence angle will also provide information of surface wind speed and direction derived from the surface return over a single 360 deg. sweep. URAD data system will be Linux based with the capability of autonomous operation. It will utilize cutting edge digital receiver and FPGA technologies to carry out the data acquisition and processing tasks. High speed navigation data from the aircraft will also be captured and saved along with radar data for 3D measurement field reconstruction and aircraft motion correction. There is a tremendous potential for UAVs to carry down-looking weather radars for measurements of reflectivity, horizontal and vertical winds from tropical storms. With operation from HUAV platforms, the dual beam X-band radar under development promises to provide greatly needed information for tropical storm research.

Duration and extent of the great auroral storm of 1859

PubMed Central

Green, James L.; Boardsen, Scott

2016-01-01

The great geomagnetic storm of August 28 through September 3, 1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world’s 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 h or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one “could read a newspaper by.” At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28–29 (~25°) and on September 2–3 (~18°). Auroral forms of all types and colors were observed below 50° latitude for ~24 h on August 28–29 and ~42 h on September 2–3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event. PMID:28066122

Duration and Extent of the Great Auroral Storm of 1859

NASA Technical Reports Server (NTRS)

Green, James L.; Boardsen, Scott

2005-01-01

The great geomagnetic storm of August 28 through September 3,1859 is, arguably, the greatest and most famous space weather event in the last two hundred years. For the first time observations showed that the sun and aurora were connected and that auroras generated strong ionospheric currents. A significant portion of the world's 200,000 km of telegraph lines were adversely affected, many of which were unusable for 8 hours or more which had a real economic impact. In addition to published scientific measurements, newspapers, ship logs, and other records of that era provide an untapped wealth of first hand observations giving time and location along with reports of the auroral forms and colors. At its height, the aurora was described as a blood or deep crimson red that was so bright that one "could read a newspaper by." At its peak, the Type A red aurora lasted for several hours and was observed to reach extremely low geomagnetic latitudes on August 28-29 (-25") and on September 2-3 (-18"). Auroral forms of all types and colors were observed below 50" latitude for -24 hours on August 28-29 and -42 hours on September 2-3. From a large database of ground-based observations the extent of the aurora in corrected geomagnetic coordinates is presented over the duration of the storm event.

Slope failure investigation management system.

DOT National Transportation Integrated Search

2013-03-01

Highway slopes are exposed to a variety of environmental and climatic conditions, such as deforestation, cycles of : freezing and thawing weather, and heavy storms. Over time, these climatic conditions, in combination with other : factors such as geo...

TestSTORM: Simulator for optimizing sample labeling and image acquisition in localization based super-resolution microscopy

PubMed Central

Sinkó, József; Kákonyi, Róbert; Rees, Eric; Metcalf, Daniel; Knight, Alex E.; Kaminski, Clemens F.; Szabó, Gábor; Erdélyi, Miklós

2014-01-01

Localization-based super-resolution microscopy image quality depends on several factors such as dye choice and labeling strategy, microscope quality and user-defined parameters such as frame rate and number as well as the image processing algorithm. Experimental optimization of these parameters can be time-consuming and expensive so we present TestSTORM, a simulator that can be used to optimize these steps. TestSTORM users can select from among four different structures with specific patterns, dye and acquisition parameters. Example results are shown and the results of the vesicle pattern are compared with experimental data. Moreover, image stacks can be generated for further evaluation using localization algorithms, offering a tool for further software developments. PMID:24688813

Significant impact of electrical storm on mortality in patients with structural heart disease and an implantable cardiac defibrillator.

PubMed

Noda, Takashi; Kurita, Takashi; Nitta, Takashi; Chiba, Yasutaka; Furushima, Hiroshi; Matsumoto, Naoki; Toyoshima, Takeshi; Shimizu, Akihiko; Mitamura, Hideo; Okumura, Ken; Ohe, Tohru; Aizawa, Yoshifusa

2018-03-15

Electrical storm (E-Storm), defined as multiple episodes of ventricular arrhythmias within a short period of time, is an important clinical problem in patients with an implantable cardiac defibrillator (ICD) including cardiac resynchronization therapy devices capable of defibrillation. The detailed clinical aspects of E-Storm in large populations especially for non-ischemic dilated cardiomyopathy (DCM), however, remain unclear. This study was performed to elucidate the detailed clinical aspects of E-Storm, such as its predictors and prevalence among patients with structural heart disease including DCM. We analyzed the data of the Nippon Storm Study, which was a prospective observational study involving 1570 patients enrolled from 48 ICD centers. For the purpose of this study, we evaluated 1274 patients with structural heart disease, including 482 (38%) patients with ischemic heart disease (IHD) and 342 (27%) patients with DCM. During a median follow-up of 28months (interquartile range: 23 to 33months), E-Storm occurred in 84 (6.6%) patients. The incidence of E-Storm was not significantly different between patients with IHD and patients with DCM (log-rank p=0.52). Proportional hazard regression analyses showed that ICD implantation for secondary prevention of sudden cardiac death (p=0.0001) and QRS width (p=0.015) were the independent risk factors for E-storm. In a comparison between patients with and without E-Storm, survival curves after adjustment for clinical characteristics showed a significant difference in mortality. E-Storm was associated with subsequent mortality in patients with structural heart disease including DCM. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Structural Variability of Tropospheric Growth Factors Transforming Mid-latitude Cyclones to Severe Storms over the North Atlantic

NASA Astrophysics Data System (ADS)

Wild, Simon; Befort, Daniel J.; Leckebusch, Gregor C.

2015-04-01

The development of European surface wind storms out of normal mid-latitude cyclones is substantially influenced by upstream tropospheric growth factors over the Northern Atlantic. The main factors include divergence and vorticity advection in the upper troposphere, latent heat release and the presence of instabilities of short baroclinic waves of suitable wave lengths. In this study we examine a subset of these potential growth factors and their related influences on the transformation of extra-tropical cyclones into severe damage prone surface storm systems. Previous studies have shown links between specific growth factors and surface wind storms related to extreme cyclones. In our study we investigate in further detail spatial and temporal variability patterns of these upstream processes at different vertical levels of the troposphere. The analyses will comprise of the three growth factors baroclinicity, latent heat release and upper tropospheric divergence. Our definition of surface wind storms is based on the Storm Severity Index (SSI) alongside a wind tracking algorithm identifying areas of exceedances of the local 98th percentile of the 10m wind speed. We also make use of a well-established extra-tropical cyclone identification and tracking algorithm. These cyclone tracks form the base for a composite analysis of the aforementioned growth factors using ERA-Interim Reanalysis from 1979 - 2014 for the extended winter season (ONDJFM). Our composite analysis corroborates previous similar studies but extends them by using an impact based algorithm for the identification of strong wind systems. Based on this composite analysis we further identify variability patterns for each growth factor most important for the transformation of a cyclone into a surface wind storm. We thus also address the question whether the link between storm intensity and related growth factor anomaly taking into account its spatial variability is stable and can be quantified. While the robustness of our preliminary results is generally dependent on the growth factor investigated, some examples include i) the overall availability of latent heat seems to be less important than its spatial structure around the cyclone core and ii) the variability of upper-tropospheric baroclinicity appears to be highest north of the surface position of the cyclone, especially for those that transform into a surface storm.

A short-term ionospheric forecasting empirical regional model (IFERM) to predict the critical frequency of the F2 layer during moderate, disturbed, and very disturbed geomagnetic conditions over the European area

NASA Astrophysics Data System (ADS)

Pietrella, M.

2012-02-01

A short-term ionospheric forecasting empirical regional model (IFERM) has been developed to predict the state of the critical frequency of the F2 layer (foF2) under different geomagnetic conditions. IFERM is based on 13 short term ionospheric forecasting empirical local models (IFELM) developed to predict foF2 at 13 ionospheric observatories scattered around the European area. The forecasting procedures were developed by taking into account, hourly measurements of foF2, hourly quiet-time reference values of foF2 (foF2QT), and the hourly time-weighted accumulation series derived from the geomagnetic planetary index ap, (ap(τ)), for each observatory. Under the assumption that the ionospheric disturbance index ln(foF2/foF2QT) is correlated to the integrated geomagnetic disturbance index ap(τ), a set of statistically significant regression coefficients were established for each observatory, over 12 months, over 24 h, and under 3 different ranges of geomagnetic activity. This data was then used as input to compute short-term ionospheric forecasting of foF2 at the 13 local stations under consideration. The empirical storm-time ionospheric correction model (STORM) was used to predict foF2 in two different ways: scaling both the hourly median prediction provided by IRI (STORM_foF2MED,IRI model), and the foF2QT values (STORM_foF2QT model) from each local station. The comparison between the performance of STORM_foF2MED,IRI, STORM_foF2QT, IFELM, and the foF2QT values, was made on the basis of root mean square deviation (r.m.s.) for a large number of periods characterized by moderate, disturbed, and very disturbed geomagnetic activity. The results showed that the 13 IFELM perform much better than STORM_foF2,sub>MED,IRI and STORM_foF2QT especially in the eastern part of the European area during the summer months (May, June, July, and August) and equinoctial months (March, April, September, and October) under disturbed and very disturbed geomagnetic conditions, respectively. The performance of IFELM is also very good in the western and central part of the Europe during the summer months under disturbed geomagnetic conditions. STORM_foF2MED,IRI performs particularly well in central Europe during the equinoctial months under moderate geomagnetic conditions and during the summer months under very disturbed geomagnetic conditions. The forecasting maps generated by IFERM on the basis of the results provided by the 13 IFELM, show very large areas located at middle-high and high latitudes where the foF2 predictions quite faithfully match the foF2 measurements, and consequently IFERM can be used for generating short-term forecasting maps of foF2 (up to 3 h ahead) over the European area.

Introduction on the operational storm surge forecasting system in Korea Operational Oceanographic System (KOOS)

NASA Astrophysics Data System (ADS)

Kwon, Jae-Il; Park, Kwang-Soon; Choi, Jung-Woon; Lee, Jong-Chan; Heo, Ki-Young; Kim, Sang-Ik

2017-04-01

During last more than 50 years, 258 typhoons passed and affected the Korean peninsula in terms of high winds, storm surges and extreme waves. In this study we explored the performance of the operational storm surge forecasting system in the Korea Operational Oceanographic System (KOOS) with 8 typhoons from 2010 to 2016. The operation storm surge forecasting system for the typhoon in KOOS is based on 2D depth averaged model with tides and CE (U.S. Army Corps of Engineers) wind model. Two key parameters of CE wind model, the locations of typhoon center and its central atmospheric pressure are based from Korea Meteorological administrative (KMA)'s typhoon information provided from 1 day to 3 hour intervals with the approach of typhoon through the KMA's web-site. For 8 typhoons cases, the overall errors, other performances and analysis such as peak time and surge duration are presented in each case. The most important factor in the storm surge errors in the operational forecasting system is the accuracy of typhoon passage prediction.

Hurricane Rita surge data, southwestern Louisiana and southeastern Texas, September to November 2005

USGS Publications Warehouse

McGee, Benton D.; Goree, Burl B.; Tollett, Roland W.; Woodward, Brenda K.; Kress, Wade H.

2006-01-01

Pressure transducers and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network consisting of 47 pressure transducers (sensors) was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast. Quality-assurance measures were used to assess the variability and accuracy of the water-level data recorded by the sensors. Water-level data from sensors were similar to data from co-located sensors, permanent U.S. Geological Survey streamgages, and water-surface elevations performed by field staff. Water-level data from sensors at selected locations were compared to corresponding high-water mark elevations. In general, the water-level data from sensors were similar to elevations of high quality high-water marks, while reporting consistently higher than elevations of lesser quality high-water marks.

How spatial and temporal rainfall variability affect runoff across basin scales: insights from field observations in the (semi-)urbanised Charlotte watershed

NASA Astrophysics Data System (ADS)

Ten Veldhuis, M. C.; Smith, J. A.; Zhou, Z.

2017-12-01

Impacts of rainfall variability on runoff response are highly scale-dependent. Sensitivity analyses based on hydrological model simulations have shown that impacts are likely to depend on combinations of storm type, basin versus storm scale, temporal versus spatial rainfall variability. So far, few of these conclusions have been confirmed on observational grounds, since high quality datasets of spatially variable rainfall and runoff over prolonged periods are rare. Here we investigate relationships between rainfall variability and runoff response based on 30 years of radar-rainfall datasets and flow measurements for 16 hydrological basins ranging from 7 to 111 km2. Basins vary not only in scale, but also in their degree of urbanisation. We investigated temporal and spatial variability characteristics of rainfall fields across a range of spatial and temporal scales to identify main drivers for variability in runoff response. We identified 3 ranges of basin size with different temporal versus spatial rainfall variability characteristics. Total rainfall volume proved to be the dominant agent determining runoff response at all basin scales, independent of their degree of urbanisation. Peak rainfall intensity and storm core volume are of secondary importance. This applies to all runoff parameters, including runoff volume, runoff peak, volume-to-peak and lag time. Position and movement of the storm with respect to the basin have a negligible influence on runoff response, with the exception of lag times in some of the larger basins. This highlights the importance of accuracy in rainfall estimation: getting the position right but the volume wrong will inevitably lead to large errors in runoff prediction. Our study helps to identify conditions where rainfall variability matters for correct estimation of the rainfall volume as well as the associated runoff response.

Quantification of non-stormwater flow entries into storm drains using a water balance approach.

PubMed

Xu, Zuxin; Yin, Hailong; Li, Huaizheng

2014-07-15

To make decisions about correcting illicit or inappropriate connections to storm drains, quantification of non-stormwater entries into storm drains was performed using a water flow balance approach, based on data analysis from 2008 to 2011 in a separate storm drainage system in a Shanghai downtown area of 374 ha. The study revealed severe sewage connections to storm drains; meanwhile, misconnections between surface water and storm drains were found to drive frequent non-stormwater pumping discharges at the outfall, producing a much larger volume of outfall flows in a short period. This paper presented a methodology to estimate quantities of inappropriate sewage flow, groundwater infiltration and river water backflow into the storm drains. It was concluded that inappropriate sewage discharge and groundwater seepage into storm drains were approximately 17,860 m(3)/d (i.e., up to 51% of the total sewage flow in the catchment) and 3,624 m(3)/d, respectively, and surface water backflow was up to an average 28,593 m(3)/d. On the basis of this work, end-of-storm pipe interceptor sewers of 0.25 m(3)/s (i.e., 21,600 m(3)/d) would be effective to tackle the problem of sewage connections and groundwater seepage to storm drains. Under this circumstance, the follow-up non-stormwater outfall pumping events indicate misconnections between surface water and storm drains, featuring pumping discharge equivalent to surface water backflow; hence the misconnections should be repaired. The information provided here is helpful in estimating the magnitude of non-stormwater flow entries into storm drains and designing the necessary pollution control activities, as well as combating city floods in storm events. Copyright © 2014. Published by Elsevier B.V.

Diagnosis and Modeling of the Explosive Development of Winter Storms: Sensitivity to PBL Schemes

NASA Astrophysics Data System (ADS)

Liberato, Margarida L. R.; Pradhan, Prabodha K.

2014-05-01

The correct representation of extreme windstorms in regional models is of great importance for impact studies of climate change. The Iberian Peninsula has recently witnessed major damage from winter extratropical intense cyclones like Klaus (January 2009), Xynthia (February 2010) and Gong (January 2013) which formed over the mid-Atlantic, experienced explosive intensification while travelling eastwards at lower latitudes than usual [Liberato et al. 2011; 2013]. In this paper the explosive development of these storms is simulated by the advanced mesoscale Weather Research and Forecasting Model (WRF v 3.4.1), initialized with NCEP Final Analysis (FNL) data as initial and lateral boundary conditions (boundary conditions updated in every 3 hours intervals). The simulation experiments are conducted with two domains, a coarser (25km) and nested (8.333km), covering the entire North Atlantic and Iberian Peninsula region. The characteristics of these storms (e.g. wind speed, precipitation) are studied from WRF model and compared with multiple observations. In this context simulations with different Planetary Boundary Layer (PBL) schemes are performed. This approach aims at understanding which mechanisms favor the explosive intensification of these storms at a lower than usual latitudes, thus improving the knowledge of atmospheric dynamics (including small-scale processes) on controlling the life cycle of midlatitude extreme storms and contributing to the improvement in predictability and in our ability to forecast storms' impacts over Iberian Peninsula. Acknowledgments: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER- 019524 (PTDC/AAC-CLI/121339/2010). References: Liberato M.L.R., J.G. Pinto, I.F. Trigo, R.M. Trigo (2011) Klaus - an exceptional winter storm over Northern Iberia and Southern France. Weather 66: 330-334 doi:10.1002/wea.755 Liberato M.L.R., J.G. Pinto, R.M. Trigo, P. Ludwig, P. Ordóñez, D. Yuen, I.F. Trigo (2013) Explosive development of winter storm Xynthia over the Subtropical North Atlantic Ocean, Nat. Hazards Earth Syst. Sci., 13, 2239-2251, doi:10.5194/nhess-13-2239-2013

Storm-time changes of geomagnetic field at MAGSAT altitudes (325-550 Km) and their comparison with changes at ground locations

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Kane, R. P.; Trivedi, N. B.

1983-01-01

The values of H, X, Y, Z at MAGSAT altitudes were first expressed as residuals delta H, delta X, delta Y, delta Z after subtracting the model HMD, XMD, YMD, ZMC. The storm-time variations of H showed that delta H (Dusk) was larger (negative) than delta H (Dawn) and occurred earlier, indicating a sort of hysteresis effect. Effects at MAGSAT altitudes were roughly the same (10% accuracy) as at ground, indicating that these effects were mostly of magnetospheric origin. The delta Y component also showed large storm-time changes. The latitudinal distribution of storm-time delta H showed north-south asymmetries varying in nature as the storm progressed. It seems that the central plane of the storm-time magnetospheric ring current undergoes latitudinal meanderings during the course of the storm.

Slope failure investigation management system : [research summary].

DOT National Transportation Integrated Search

2013-03-01

Highway slopes are exposed to a variety of environmental and climatic conditions, : such as deforestation, cycles of freezing and thawing weather, and heavy storms. : Over time, these climatic conditions, in combination with other factors such as : g...

Testing the Storm et al. (2010) meta-analysis using Bayesian and frequentist approaches: reply to Rouder et al. (2013).

PubMed

Storm, Lance; Tressoldi, Patrizio E; Utts, Jessica

2013-01-01

Rouder, Morey, and Province (2013) stated that (a) the evidence-based case for psi in Storm, Tressoldi, and Di Risio's (2010) meta-analysis is supported only by a number of studies that used manual randomization, and (b) when these studies are excluded so that only investigations using automatic randomization are evaluated (and some additional studies previously omitted by Storm et al., 2010, are included), the evidence for psi is "unpersuasive." Rouder et al. used a Bayesian approach, and we adopted the same methodology, finding that our case is upheld. Because of recent updates and corrections, we reassessed the free-response databases of Storm et al. using a frequentist approach. We discuss and critique the assumptions and findings of Rouder et al. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Movie-maps of low-latitude magnetic storm disturbance

NASA Astrophysics Data System (ADS)

Love, Jeffrey J.; Gannon, Jennifer L.

2010-06-01

We present 29 movie-maps of low-latitude horizontal-intensity magnetic disturbance for the years 1999-2006: 28 recording magnetic storms and 1 magnetically quiescent period. The movie-maps are derived from magnetic vector time series data collected at up to 25 ground-based observatories. Using a technique similar to that used in the calculation of Dst, a quiet time baseline is subtracted from the time series from each observatory. The remaining disturbance time series are shown in a polar coordinate system that accommodates both Earth rotation and the universal time dependence of magnetospheric disturbance. Each magnetic storm recorded in the movie-maps is different. While some standard interpretations about the storm time equatorial ring current appear to apply to certain moments and certain phases of some storms, the movie-maps also show substantial variety in the local time distribution of low-latitude magnetic disturbance, especially during storm commencements and storm main phases. All movie-maps are available at the U.S. Geological Survey Geomagnetism Program Web site (http://geomag.usgs.gov).

A Flux-Corrected Transport Based Hydrodynamic Model for the Plasmasphere Refilling Problem following Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Chatterjee, K.; Schunk, R. W.

2017-12-01

The refilling of the plasmasphere following a geomagnetic storm remains one of the longstanding problems in the area of ionosphere-magnetosphere coupling. Both diffusion and hydrodynamic approximations have been adopted for the modeling and solution of this problem. The diffusion approximation neglects the nonlinear inertial term in the momentum equation and so this approximation is not rigorously valid immediately after the storm. Over the last few years, we have developed a hydrodynamic refilling model using the flux-corrected transport method, a numerical method that is extremely well suited to handling nonlinear problems with shocks and discontinuities. The plasma transport equations are solved along 1D closed magnetic field lines that connect conjugate ionospheres and the model currently includes three ion (H+, O+, He+) and two neutral (O, H) species. In this work, each ion species under consideration has been modeled as two separate streams emanating from the conjugate hemispheres and the model correctly predicts supersonic ion speeds and the presence of high levels of Helium during the early hours of refilling. The ultimate objective of this research is the development of a 3D model for the plasmasphere refilling problem and with additional development, the same methodology can potentially be applied to the study of other complex space plasma coupling problems in closed flux tube geometries. Index Terms: 2447 Modeling and forecasting [IONOSPHERE] 2753 Numerical modeling [MAGNETOSPHERIC PHYSICS] 7959 Models [SPACE WEATHER

Interannual Variability in Global Dust Storm Initiation on Mars from a GCM with Orbit-Spin Coupling and Active Dust Lifting

NASA Astrophysics Data System (ADS)

Mischna, M.; Shirley, J. H.; Newman, C. E.

2016-12-01

To first order, the occurrence and interannual variability of global dust storms (GDS) on Mars is attributable to two factors: the annual cycle of solar insolation (which delineates a specific `dust storm season'), and the changing spatial distribution and availability of dust at the surface. Recent work has now found a remarkable correspondence between the occurrence of GDS on Mars and years in which the orbital angular momentum of Mars is increasing during the dust storm season. A previously undefined acceleration term `couples' this orbital motion to the rotational motion of the planet and atmosphere, and small but persistent atmospheric accelerations (so-called `coupling term accelerations,' or CTA) change the atmospheric circulation in such a way as to seemingly be favorable to storm development. This becomes a third factor, then, that may regulate the occurrence and variability of GDS. Our prior work with the MarsWRF general circulation model (GCM) was performed either with no atmospheric dust, or with simplified, prescribed dust distributions, and illustrated the dual roles of both insolation and CTA on GDS variability. Recent advances in the MarsWRF GCM dust prescription can now tackle the remaining unaddressed factor: the role of dust availability in controlling the initiation of GDS. Simulations with both infinite and finite global sources of dust have been performed. For a prescribed dust lifting threshold, surface dust is removed from the surface, preferentially from locations with larger surface stress values, transported in the atmosphere and deposited at a later time. Compared to simulations without CTA, those with CTA show more realism in the variability of timing and magnitude of atmospheric dustiness during the dust storm season. For infinite surface dust, the primary dust lifting (peak wind stress) regions are spatially restricted, and year-to-year changes are largely due to variations in the CTA at these few locations. By contrast, in simulations with finite surface dust, the peak stress regions are rapidly exhausted, leading to a far greater distribution of primary dust lifting regions; hence, variations in the CTA over a wider area contribute to the interannual variability of GDS. Results from our suite of simulations will be shown, vis-à-vis the historical record of GDS on Mars.

A global scale picture of ionospheric peak electron density changes during geomagnetic storms

NASA Astrophysics Data System (ADS)

Kumar, Vickal V.; Parkinson, Murray L.

2017-04-01

Changes in ionospheric plasma densities can affect society more than ever because of our increasing reliance on communication, surveillance, navigation, and timing technology. Models struggle to predict changes in ionospheric densities at nearly all temporal and spatial scales, especially during geomagnetic storms. Here we combine a 50 year (1965-2015) geomagnetic disturbance storm time (Dst) index with plasma density measurements from a worldwide network of 132 vertical incidence ionosondes to develop a picture of global scale changes in peak plasma density due to geomagnetic storms. Vertical incidence ionosondes provide measurements of the critical frequency of the ionospheric F2 layer (foF2), a direct measure of the peak electron density (NmF2) of the ionosphere. By dissecting the NmF2 perturbations with respect to the local time at storm onset, season, and storm intensity, it is found that (i) the storm-associated depletions (negative storm effects) and enhancements (positive storm effects) are driven by different but related physical mechanisms, and (ii) the depletion mechanism tends to dominate over the enhancement mechanism. The negative storm effects, which are detrimental to HF radio links, are found to start immediately after geomagnetic storm onset in the nightside high-latitude ionosphere. The depletions in the dayside high-latitude ionosphere are delayed by a few hours. The equatorward expansion of negative storm effects is found to be regulated by storm intensity (farthest equatorward and deepest during intense storms), season (largest in summer), and time of day (generally deeper on the nightside). In contrast, positive storm effects typically occur on the dayside midlatitude and low-latitude ionospheric regions when the storms are in the main phase, regardless of the season. Closer to the magnetic equator, moderate density enhancements last up to 40 h during the recovery phase of equinox storms, regardless of the local time. Strikingly, high-latitude plasma densities are moderately enhanced for up to 60 h prior to the actual onset of storms during the equinoxes and summer; a potential precursor of a geomagnetic storm.

The strength and hemispheric asymmetry of Equatorial Ionization Anomaly during two geomagnetic storms in 2013 from Global Ionosphere Map and SAMI2

NASA Astrophysics Data System (ADS)

Luo, Weihua; Zhu, Zhengping; Lan, Jiaping

2016-08-01

The variations of the strength and the hemispheric asymmetry of EIA were studied by Global Ionosphere Map (GIM) and SAMI2 during two geomagnetic storm periods in March and June 2013. Compared with the 30-days median TEC, the TEC at the two crests of EIA had small variations while the TEC at the trough had a more remarkable variation for the two storms after the SSC. The TEC difference between the two EIA peaks had an increase or decrease several hours after the SSC, the asymmetry between the two crests of EIA represented by the defined asymmetry index has no obvious variations except several hours after the SSC, and EIA strength represented by the Crest-to-Trough Ratio (CTR) had a remarkable increase one day after the SSC day for March storm and decrease several hours after the SSC for June storm. The variations last several hours, with more than 40% variations compared with the value during the quiet period. The EIA peaks were also found to move toward the equator after the SSC during the two storms. The simulation from SAMI2 and HWM07 also shows that EIA crests would move toward the equator during storm time and EIA strength would decrease, which suggests that the disturbed neutral wind and disturbed electric field may be important factors affecting the EIA during the storm periods.

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

USGS Publications Warehouse

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

2017-01-01

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

Time-lag and Correlation between ACE and RBSPICE Injection Event Observations during Storm Times

NASA Astrophysics Data System (ADS)

Madanian, H.; Patterson, J. D.; Manweiler, J. W.; Soto-chavez, A. R.; Gerrard, A. J.; Lanzerotti, L. J.

2017-12-01

The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on the Van Allen Probes mission measures energetic charged particles [ 20 keV to 1 MeV] in the inner magnetosphere and ring current. During geomagnetic storms, injections of energetic ions into the ring current change the ion population and produce geomagnetic field depressions on Earth's surface. We analyzed the magnetic field strength and particle composition in the interplanetary medium measured by instruments on the Advanced Composition Explorer (ACE) spacecraft near the inner Lagrangian point. The Electron, Proton, and Alpha Monitor-Low Energy Magnetic Spectrometer (EPAM-LEMS) sensor on ACE measures energetic particles [ 50 keV to 5 MeV] in the interplanetary space. The SYM-H index is utilized to classify the storm events by magnitude and to select more than 60 storm events between 2013 and 2017. We cross-compared ACE observations at storm times, with the RBSPICE ion measurements at dusk to midnight magnetic local time and over the 3-6 L-shell range. We report on the relative composition of the solar particles and the relative composition of the inner magnetospheric hot plasma during storm times. The data correlation is accomplished by shifting the observation time from ACE to RBSPICE using the solar wind velocity at the time of the observation. We will discuss time lags between storm onset at the magnetopause and injection events measured for each storm.

Ionospheric TEC, thermospheric cooling and Σ[O/N2] compositional changes during the 6-17 March 2012 magnetic storm interval (CAWSES II)

NASA Astrophysics Data System (ADS)

Verkhoglyadova, O. P.; Tsurutani, B. T.; Mannucci, A. J.; Mlynczak, M. G.; Hunt, L. A.; Paxton, L. J.

2014-08-01

A series of four geomagnetic storms (the minimum SYM-H~-148 nT) occurred during the March 6-17, 2012 in the ascending phase of the solar cycle 24. This interval was selected by CAWSES II for its campaign. The GPS total electron content (TEC) database and JPL's Global Ionospheric Maps (GIM) were used to study vertical TEC (VTEC) for different local times and latitude ranges. The largest response to geomagnetic activity is shown in increases of the low-latitude dayside VTEC. Several GPS sites feature post-afternoon VTEC “bite-outs”. During Sudden Impulse (SI+) event on March 8th a peak daytime VTEC restores to about quiet-time values. It is shown that the TIMED/SABER zonal flux of nitric oxide (NO) infrared cooling radiation correlates well with auroral heating. A factor of ~5 cooling increase is noted in some storms. The cooling radiation intensifies in the auroral zone and spreads towards the equator. Effects of the storm appear at lower latitudes ~18.6 h later. The column density ratio Σ[O/N2] is analyzed based on TIMED/GUVI measurements. Both increases (at low latitudes) and decreases (from auroral to middle latitudes) in the ratio occurs during the geomagnetic storms. We suggest that the column density ratio could be enhanced at low to middle latitudes on the dayside partially due to the superfountain effect (atomic oxygen uplift due to ion-neutral drag). It is suggested that decreases in the Σ[O/N2] ratio at high to middle-latitudes may be caused by high thermospheric temperatures. During SI+s, there is an increase in Σ[O/N2] ratio at auroral latitudes.

Coastal emergency managers' preferences for storm surge forecast communication.

PubMed

Morrow, Betty Hearn; Lazo, Jeffrey K

2014-01-01

Storm surge, the most deadly hazard associated with tropical and extratropical cyclones, is the basis for most evacuation decisions by authorities. One factor believed to be associated with evacuation noncompliance is a lack of understanding of storm surge. To address this problem, federal agencies responsible for cyclone forecasts are seeking more effective ways of communicating storm surge threat. To inform this process, they are engaging various partners in the forecast and warning process.This project focuses on emergency managers. Fifty-three emergency managers (EMs) from the Gulf and lower Atlantic coasts were surveyed to elicit their experience with, sources of, and preferences for storm surge information. The emergency managers-who are well seasoned in hurricane response and generally rate the surge risk in their coastal areas above average or extremely high-listed storm surge as their major concern with respect to hurricanes. They reported a general lack of public awareness about surge. Overall they support new ways to convey the potential danger to the public, including the issuance of separate storm surge watches and warnings, and the expression of surge heights using feet above ground level. These EMs would like more maps, graphics, and visual materials for use in communicating with the public. An important concern is the timing of surge forecasts-whether they receive them early enough to be useful in their evacuation decisions.

Flood Identification from Satellite Images Using Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Chang, L.; Kao, I.; Shih, K.

2011-12-01

Typhoons and storms hit Taiwan several times every year and they cause serious flood disasters. Because the rivers are short and steep, and their flows are relatively fast with floods lasting only few hours and usually less than one day. Flood identification can provide the flood disaster and extent information to disaster assistance and recovery centers. Due to the factors of the weather, it is not suitable for aircraft or traditional multispectral satellite; hence, the most appropriate way for investigating flooding extent is to use Synthetic Aperture Radar (SAR) satellite. In this study, back-propagation neural network (BPNN) model and multivariate linear regression (MLR) model are built to identify the flooding extent from SAR satellite images. The input variables of the BPNN model are Radar Cross Section (RCS) value and mean of the pixel, standard deviation, minimum and maximum of RCS values among its adjacent 3×3 pixels. The MLR model uses two images of the non-flooding and flooding periods, and The inputs are the difference between the RCS values of two images and the variances among its adjacent 3×3 pixels. The results show that the BPNN model can perform much better than the MLR model. The correct percentages are more than 80% and 73% in training and testing data, respectively. Many misidentified areas are very fragmented and unrelated. In order to reinforce the correct percentage, morphological image analysis is used to modify the outputs of these identification models. Through morphological operations, most of the small, fragmented and misidentified areas can be correctly assigned to flooding or non-flooding areas. The final results show that the flood identification of satellite images has been improved a lot and the correct percentages increases up to more than 90%.

Swashed away? Storm impacts on sandy beach macrofaunal communities

NASA Astrophysics Data System (ADS)

Harris, Linda; Nel, Ronel; Smale, Malcolm; Schoeman, David

2011-09-01

Storms can have a large impact on sandy shores, with powerful waves eroding large volumes of sand off the beach. Resulting damage to the physical environment has been well-studied but the ecological implications of these natural phenomena are less known. Since climate change predictions suggest an increase in storminess in the near future, understanding these ecological implications is vital if sandy shores are to be proactively managed for resilience. Here, we report on an opportunistic experiment that tests the a priori expectation that storms impact beach macrofaunal communities by modifying natural patterns of beach morphodynamics. Two sites at Sardinia Bay, South Africa, were sampled for macrofauna and physical descriptors following standard sampling methods. This sampling took place five times at three- to four-month intervals between April 2008 and August 2009. The second and last sampling events were undertaken after unusually large storms, the first of which was sufficiently large to transform one site from a sandy beach into a mixed shore for the first time in living memory. A range of univariate (linear mixed-effects models) and multivariate (e.g. non-metric multidimensional scaling, PERMANOVA) methods were employed to describe trends in the time series, and to explore the likelihood of possible explanatory mechanisms. Macrofaunal communities at the dune-backed beach (Site 2) withstood the effects of the first storm but were altered significantly by the second storm. In contrast, macrofauna communities at Site 1, where the supralittoral had been anthropogenically modified so that exchange of sediments with the beach was limited, were strongly affected by the first storm and showed little recovery over the study period. In line with predictions from ecological theory, beach morphodynamics was found to be a strong driver of temporal patterns in the macrofaunal community structure, with the storm events also identified as a significant factor, likely because of their direct effects on beach morphodynamics. Our results also support those of other studies suggesting that developed shores are more impacted by storms than are undeveloped shores. Whilst recognising we cannot generalise too far beyond our limited study, our results contribute to the growing body of evidence that interactions between sea-level rise, increasing storminess and the expansion of anthropogenic modifications to the shoreline will place functional beach ecosystems under severe pressure over the forthcoming decades and we therefore encourage further, formal testing of these concepts.

The dual effect of vegetation green-up date and strong wind on the return period of spring dust storms.

PubMed

Feng, Jieling; Li, Ning; Zhang, Zhengtao; Chen, Xi

2017-08-15

Vegetation phenology changes have been widely applied in the disaster risk assessments of the spring dust storms, and vegetation green-up date shifts have a strong influence on dust storms. However, the effect of earlier vegetation green-up dates due to climate warming on the evaluation of dust storms return periods remains an important, but poorly understood issue. In this study, we evaluate the spring dust storm return period (February to June) in Inner Mongolia, Northern China, using 165 observations of severe spring dust storm events from 16 weather stations, and regional vegetation green-up dates as an integrated factor from NDVI (Normalized Difference Vegetation Index), covering a period from 1982 to 2007, by building the bivariate Copula model. We found that the joint return period showed better fitting results than without considering the integrated factor when the actual dust storm return period is longer than 2years. Also, for extremely severe dust storm events, the gap between simulation result and actual return period can be narrowed up to 0.4888years by using integrated factor. Furthermore, the risk map based on the return period results shows that the Mandula, Zhurihe, Sunitezuoqi, Narenbaolige stations are identified as high risk areas. In this study area, land surface is extensively covered by grasses and shrubs, vegetation green-up date can play a significant role in restraining spring dust storm outbreaks. Therefore, we suggest that Copula method can become a useful tool for joint return period evaluation and risk analysis of severe dust storms. Copyright © 2017 Elsevier B.V. All rights reserved.

Probability of occurrence of planetary ionosphere storms associated with the magnetosphere disturbance storm time events

NASA Astrophysics Data System (ADS)

Gulyaeva, T. L.; Arikan, F.; Stanislawska, I.

2014-11-01

The ionospheric W index allows to distinguish state of the ionosphere and plasmasphere from quiet conditions (W = 0 or ±1) to intense storm (W = ±4) ranging the plasma density enhancements (positive phase) or plasma density depletions (negative phase) regarding the quiet ionosphere. The global W index maps are produced for a period 1999-2014 from Global Ionospheric Maps of Total Electron Content, GIM-TEC, designed by Jet Propulson Laboratory, converted from geographic frame (-87.5:2.5:87.5° in latitude, -180:5:180° in longitude) to geomagnetic frame (-85:5:85° in magnetic latitude, -180:5:180° in magnetic longitude). The probability of occurrence of planetary ionosphere storm during the magnetic disturbance storm time, Dst, event is evaluated with the superposed epoch analysis for 77 intense storms (Dst ≤ -100 nT) and 230 moderate storms (-100 < Dst ≤ -50 nT) with start time, t0, defined at Dst storm main phase onset. It is found that the intensity of negative storm, iW-, exceeds the intensity of positive storm, iW+, by 1.5-2 times. An empirical formula of iW+ and iW- in terms of peak Dst is deduced exhibiting an opposite trends of relation of intensity of ionosphere-plasmasphere storm with regard to intensity of Dst storm.

Ring Current Dynamics in Moderate and Strong Storms: Comparative Analysis of TWINS and IMAGE/HENA Data with the Comprehensive Ring Current Model

NASA Technical Reports Server (NTRS)

Buzulukova, N.; Fok, M.-C.; Goldstein, J.; Valek, P.; McComas, D. J.; Brandt, P. C.

2010-01-01

We present a comparative study of ring current dynamics during strong and moderate storms. The ring current during the strong storm is studied with IMAGE/HENA data near the solar cycle maximum in 2000. The ring current during the moderate storm is studied using energetic neutral atom (ENA) data from the Two Wide-Angle Imaging Neutral- Atom Spectrometers (TWINS) mission during the solar minimum in 2008. For both storms, the local time distributions of ENA emissions show signatures of postmidnight enhancement (PME) during the main phases. To model the ring current and ENA emissions, we use the Comprehensive Ring Current Model (CRCM). CRCM results show that the main-phase ring current pressure peaks in the premidnight-dusk sector, while the most intense CRCM-simulated ENA emissions show PME signatures. We analyze two factors to explain this difference: the dependence of charge-exchange cross section on energy and pitch angle distributions of ring current. We find that the IMF By effect (twisting of the convection pattern due to By) is not needed to form the PME. Additionally, the PME is more pronounced for the strong storm, although relative shielding and hence electric field skewing is well developed for both events.

Nitrate Removal Rates in Denitrifying Bioreactors During Storm Flows

NASA Astrophysics Data System (ADS)

Pluer, W.; Walter, T.

2017-12-01

Field denitrifying bioreactors are designed to reduce excess nitrate (NO3-) pollution in runoff from agricultural fields. Field bioreactors saturate organic matter to create conditions that facilitate microbial denitrification. Prior studies using steady flow in lab-scale bioreactors showed that a hydraulic retention time (HRT) between 4 and 10 hours was optimal for reducing NO3- loads. However, during storm-induced events, flow rate and actual HRT fluctuate. These fluctuations have the potential to disrupt the system in significant ways that are not captured by the idealized steady-flow HRT models. The goal of this study was to investigate removal rate during dynamic storm flows of variable rates and durations. Our results indicate that storm peak flow and duration were not significant controlling variables. Instead, we found high correlations (p=0.004) in average removal rates between bioreactors displaying a predominantly uniform flow pattern compared with bioreactors that exhibited preferential flow (24.4 and 21.4 g N m-3 d-1, respectively). This suggests that the internal flow patterns are a more significant driver of removal rate than external factors of the storm hydrograph. Designing for flow patterns in addition to theoretical HRT will facilitate complete mixing within the bioreactors. This will help maximize excess NO3- removal during large storm-induced runoff events.

Progress in the Study of Coastal Storm Deposits

NASA Astrophysics Data System (ADS)

Xiong, Haixian; Huang, Guangqing; Fu, Shuqing; Qian, Peng

2018-05-01

Numerous studies have been carried out to identify storm deposits and decipher storm-induced sedimentary processes in coastal and shallow-marine areas. This study aims to provide an in-depth review on the study of coastal storm deposits from the following five aspects. 1) The formation of storm deposits is a function of hydrodynamic and sedimentary processes under the constraints of local geological and ecological factors. Many questions remain to demonstrate the genetic links between storm-related processes and a variety of resulting deposits such as overwash deposits, underwater deposits and hummocky cross-stratification (HCS). Future research into the formation of storm deposits should combine flume experiments, field observations and numerical simulations, and make full use of sediment source tracing methods. 2) Recently there has been rapid growth in the number of studies utilizing sediment provenance analysis to investigate the source of storm deposits. The development of source tracing techniques, such as mineral composition, magnetic susceptibility, microfossil and geochemical property, has allowed for better understanding of the depositional processes and environmental changes associated with coastal storms. 3) The role of extreme storms in the sedimentation of low-lying coastal wetlands with diverse ecosystem services has also drawn a great deal of attention. Many investigations have attempted to quantify widespread land loss, vertical marsh sediment accumulation and wetland elevation change induced by major hurricanes. 4) Paleostorm reconstructions based on storm sedimentary proxies have shown many advantages over the instrumental records and historic documents as they allow for the reconstruction of storm activities on millennial or longer time scales. Storm deposits having been used to establish proxies mainly include beach ridges and shelly cheniers, coral reefs, estuary-deltaic storm sequences and overwash deposits. Particularly over the past few decades, the proxies developed from overwash deposits have successfully retrieved many records of storm activities during the mid to late Holocene worldwide. 5) Distinguishing sediments deposited by storms and tsunamis is one of the most difficult issues among the many aspects of storm deposit studies. Comparative studies have investigated numerous diagnostic evidences including hydrodynamic condition, landward extent, grain property, texture and grading, thickness, microfossil assemblage and landscape conformity. Perhaps integrating physical, biological and geochemical evidences will, in the future, allow unambiguous identification of tsunami deposits and storm deposits.

Synoptic analysis and hindcast of an intense bow echo in Western Europe: The 09 June 2014 storm

NASA Astrophysics Data System (ADS)

Mathias, Luca; Ermert, Volker; Kelemen, Fanni D.; Ludwig, Patrick; Pinto, Joaquim G.

2017-04-01

On Pentecost Monday of 09 June 2014, a severe mesoscale convective system (MCS) hit Belgium and Western Germany. This storm was one of the most severe thunderstorms in Germany for decades. The synoptic-scale and mesoscale characteristics of this storm are analyzed based on remote sensing data and in-situ measurements. Moreover, the forecast potential of the storm is evaluated using sensitivity experiments with a regional climate model. The key ingredients for the development of the Pentecost storm were the concurrent presence of low-level moisture, atmospheric conditional instability and wind shear. The synoptic and mesoscale analysis shows that the outflow of a decaying MCS above northern France triggered the storm, which exhibited the typical features of a bow echo like a mesovortex and rear inflow jet. This resulted in hurricane-force wind gusts (reaching 40 m/s) along a narrow swath in the Rhine-Ruhr region leading to substantial damage. Operational numerical weather predictions models mostly failed to forecast the storm, but high-resolution regional model hindcasts enable a realistic simulation of the storm. The model experiments reveal that the development of the bow echo is particularly sensitive to the initial wind field and the lower tropospheric moisture content. Correct initial and boundary conditions are therefore necessary for realistic numerical forecasts of such a bow echo event. We conclude that the Pentecost storm exhibited a comparable structure and a similar intensity to the observed bow echo systems in the United States.

Use of Historical Radar Rainfall Estimates to Develop Design Storms in Los Angeles.

NASA Astrophysics Data System (ADS)

Curtis, D. C.; Humphrey, J.; Moffitt, J.

2007-12-01

A database of 15-minute historical gage adjusted radar-rainfall estimates was used to evaluate the geometric properties of storms in the City of Los Angeles, CA. The database includes selected months containing significant rainfall during the period 1996-2007. For each time step, areas of contiguous rainfall were identified as individual storm cells. An idealized ellipse was fit to each storm cell and the properties of the ellipse (e.g., size, shape, orientation, velocity and other parameters) were recorded. To accurately account for the range of storm cell sizes, capture a large number of storm cells in a climatologically similar area, assess the variability of storm movement, and minimize the impact of edge effects (i.e., incomplete coverage of cells entering and leaving), a study area substantially larger than the City of Los Angeles was used. The study area extends from city center to 30 miles north to the crest of San Gabriel Mountains, 45 miles east to Ontario, 60 miles south to Santa Catalina Island, and 70 miles west to Oxnard, an area of about10,000 square miles. Radar data for this area over 30 months in the study yields many thousands of storm cells for analysis. Storms were separated into classes by origin, direction and speed of movement. Preliminary investigations considers three types: Arctic origin (west-northwest), Pacific origin (southwest) and Tropical origin (south or stationary). Radar data (for 1996-2007) and upper air maps (1948-2006) are used to identify the direction and speed of significant precipitation events. Typical duration and temporal patterns of Los Angeles historical storms were described by season and storm type. Time of maximum intensity loading variation were determined for a selection of historic storms Depth-Areal Reduction Factors (DARF) for cloudbursts were developedfrom the radar data. These data curves are fit to equations showing the relationships between DARF, area and central intensity. Separate DARF curves are developed for 6X (6 events per year), 4X, 3X, 2X, 1, 2, 5 and 10 year recurrence, and durations from 5 minutes to 7-days. A comparison is made between DARF derived in these analyses with NOAA Atlas 12 DARF, the USACE Sierra Madre Storm and other DARF developed for the interior Southwest. Orographic increases in DDF are related to the Los Angeles County Flood Control District Hydrology Manual 24-hr 50-yr Precipitation maps, elevation from USGS topographic maps and Mean Annual Precipitation maps.

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy

PubMed Central

Kim, Dahan; Curthoys, Nikki M.; Parent, Matthew T.; Hess, Samuel T.

2015-01-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined. PMID:26185614

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy.

PubMed

Kim, Dahan; Curthoys, Nikki M; Parent, Matthew T; Hess, Samuel T

2013-09-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined.

A Bayes Factor Meta-Analysis of Recent Extrasensory Perception Experiments: Comment on Storm, Tressoldi, and Di Risio (2010)

ERIC Educational Resources Information Center

Rouder, Jeffrey N.; Morey, Richard D.; Province, Jordan M.

2013-01-01

Psi phenomena, such as mental telepathy, precognition, and clairvoyance, have garnered much recent attention. We reassess the evidence for psi effects from Storm, Tressoldi, and Di Risio's (2010) meta-analysis. Our analysis differs from Storm et al.'s in that we rely on Bayes factors, a Bayesian approach for stating the evidence from data for…

Motivations and sensation seeking characteristics of recreational storm chasers

Treesearch

Shuangyu Xu; Sonja Wilhelm Stanis; Carla Barbieri; Jiawen Chen

2012-01-01

Little is known about recreational storm chasing, a type of risk recreation that has increased in popularity since the 1990s. This study was conducted to understand factors associated with participation in recreational storm chasing in the United States. Particularly, this study assessed the motivations and sensation seeking attributes of recreational storm chasers, as...

The Additional Secondary Phase Correction System for AIS Signals

PubMed Central

Wang, Xiaoye; Zhang, Shufang; Sun, Xiaowen

2017-01-01

This paper looks at the development and implementation of the additional secondary phase factor (ASF) real-time correction system for the Automatic Identification System (AIS) signal. A large number of test data were collected using the developed ASF correction system and the propagation characteristics of the AIS signal that transmits at sea and the ASF real-time correction algorithm of the AIS signal were analyzed and verified. Accounting for the different hardware of the receivers in the land-based positioning system and the variation of the actual environmental factors, the ASF correction system corrects original measurements of positioning receivers in real time and provides corrected positioning accuracy within 10 m. PMID:28362330

An empirical probability density distribution of planetary ionosphere storms with geomagnetic precursors

NASA Astrophysics Data System (ADS)

Gulyaeva, Tamara; Stanislawska, Iwona; Arikan, Feza; Arikan, Orhan

The probability of occurrence of the positive and negative planetary ionosphere storms is evaluated using the W index maps produced from Global Ionospheric Maps of Total Electron Content, GIM-TEC, provided by Jet Propulsion Laboratory, and transformed from geographic coordinates to magnetic coordinates frame. The auroral electrojet AE index and the equatorial disturbance storm time Dst index are investigated as precursors of the global ionosphere storm. The superposed epoch analysis is performed for 77 intense storms (Dst≤-100 nT) and 227 moderate storms (-100

Effects of assimilating precipitation zones derived from satellite and lightning data on numerical simulations of tropical-like Mediterranean storms

NASA Astrophysics Data System (ADS)

Fita, L.; Romero, R.; Luque, A.; Ramis, C.

2009-08-01

The scarcity of meteorological observations in maritime areas is a well-known problem that can be an important limitation in the study of different phenomena. Tropical-like storms or medicanes developed over the Mediterranean sea are intense storms with some similarities to the tropical ones. Although they do not reach the hurricane intensity, their potential for damage is very high, due to the densely populated Mediterranean coastal regions. In this study, the two notable cases of medicane development which occurred in the western Mediterranean basin in September 1996 and October 2003, are considered. The capability of mesoscale numerical models to simulate general aspects of such a phenomena has been previously shown. With the aim of improving the numerical results, an adjustment of the humidity vertical profiles in MM5 simulations is performed by means of satellite derived precipitation. Convective and stratiform precipitation types obtained from satellite images are used to individually adjust the profiles. Lightning hits are employed to identify convective grid points. The adjustment of the vertical humidity profiles is carried out in the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses used as initial conditions for the simulations. Analyses nudging to ECMWF analyses and to the satellite-based humidity-corrected version of these analyses has also been applied using Four Dimensional Data Assimilation (FDDA). An additional adjustment is applied as observation nudging of satellite/lightning information at different time and spatial resolutions. Statistical parameters are proposed and tested as an objective way to intercompare satellite-derived and simulated trajectories. Simulations of medicanes exhibit a strong sensitivity to vertical humidity profiles. Trajectories of the storms are improved or worsened by using FDDA. A case dependence is obtained on the characteristics of the humidity-corrected medicanes. FDDA sensitivity on temporal and spatial resolution of the assimilated data also presents a case dependence. It also shows a significant sensitivity of the results of the observation nudging to the specific choice of the values of coefficient weight and vertical ratio of the ingested observations.

Methodology for time-domain estimation of storm time geoelectric fields using the 3-D magnetotelluric response tensors

USGS Publications Warehouse

Kelbert, Anna; Balch, Christopher; Pulkkinen, Antti; Egbert, Gary D; Love, Jeffrey J.; Rigler, E. Joshua; Fujii, Ikuko

2017-01-01

Geoelectric fields at the Earth's surface caused by magnetic storms constitute a hazard to the operation of electric power grids and related infrastructure. The ability to estimate these geoelectric fields in close to real time and provide local predictions would better equip the industry to mitigate negative impacts on their operations. Here we report progress toward this goal: development of robust algorithms that convolve a magnetic storm time series with a frequency domain impedance for a realistic three-dimensional (3-D) Earth, to estimate the local, storm time geoelectric field. Both frequency domain and time domain approaches are presented and validated against storm time geoelectric field data measured in Japan. The methods are then compared in the context of a real-time application.

Methodology for time-domain estimation of storm time geoelectric fields using the 3-D magnetotelluric response tensors

NASA Astrophysics Data System (ADS)

Kelbert, Anna; Balch, Christopher C.; Pulkkinen, Antti; Egbert, Gary D.; Love, Jeffrey J.; Rigler, E. Joshua; Fujii, Ikuko

2017-07-01

Geoelectric fields at the Earth's surface caused by magnetic storms constitute a hazard to the operation of electric power grids and related infrastructure. The ability to estimate these geoelectric fields in close to real time and provide local predictions would better equip the industry to mitigate negative impacts on their operations. Here we report progress toward this goal: development of robust algorithms that convolve a magnetic storm time series with a frequency domain impedance for a realistic three-dimensional (3-D) Earth, to estimate the local, storm time geoelectric field. Both frequency domain and time domain approaches are presented and validated against storm time geoelectric field data measured in Japan. The methods are then compared in the context of a real-time application.

Empirical Orthogonal Function (EOF) Analysis of Storm-Time GPS Total Electron Content Variations

NASA Astrophysics Data System (ADS)

Thomas, E. G.; Coster, A. J.; Zhang, S.; McGranaghan, R. M.; Shepherd, S. G.; Baker, J. B.; Ruohoniemi, J. M.

2016-12-01

Large perturbations in ionospheric density are known to occur during geomagnetic storms triggered by dynamic structures in the solar wind. These ionospheric storm effects have long attracted interest due to their impact on the propagation characteristics of radio wave communications. Over the last two decades, maps of vertically-integrated total electron content (TEC) based on data collected by worldwide networks of Global Positioning System (GPS) receivers have dramatically improved our ability to monitor the spatiotemporal dynamics of prominent storm-time features such as polar cap patches and storm enhanced density (SED) plumes. In this study, we use an empirical orthogonal function (EOF) decomposition technique to identify the primary modes of spatial and temporal variability in the storm-time GPS TEC response at midlatitudes over North America during more than 100 moderate geomagnetic storms from 2001-2013. We next examine the resulting time-varying principal components and their correlation with various geophysical indices and parameters in order to derive an analytical representation. Finally, we use a truncated reconstruction of the EOF basis functions and parameterization of the principal components to produce an empirical representation of the geomagnetic storm-time response of GPS TEC for all magnetic local times local times and seasons at midlatitudes in the North American sector.

Predictability of tropical cyclone events on intraseasonal timescales with the ECMWF monthly forecast model

NASA Astrophysics Data System (ADS)

Elsberry, Russell L.; Jordan, Mary S.; Vitart, Frederic

2010-05-01

The objective of this study is to provide evidence of predictability on intraseasonal time scales (10-30 days) for western North Pacific tropical cyclone formation and subsequent tracks using the 51-member ECMWF 32-day forecasts made once a week from 5 June through 25 December 2008. Ensemble storms are defined by grouping ensemble member vortices whose positions are within a specified separation distance that is equal to 180 n mi at the initial forecast time t and increases linearly to 420 n mi at Day 14 and then is constant. The 12-h track segments are calculated with a Weighted-Mean Vector Motion technique in which the weighting factor is inversely proportional to the distance from the endpoint of the previous 12-h motion vector. Seventy-six percent of the ensemble storms had five or fewer member vortices. On average, the ensemble storms begin 2.5 days before the first entry of the Joint Typhoon Warning Center (JTWC) best-track file, tend to translate too slowly in the deep tropics, and persist for longer periods over land. A strict objective matching technique with the JTWC storms is combined with a second subjective procedure that is then applied to identify nearby ensemble storms that would indicate a greater likelihood of a tropical cyclone developing in that region with that track orientation. The ensemble storms identified in the ECMWF 32-day forecasts provided guidance on intraseasonal timescales of the formations and tracks of the three strongest typhoons and two other typhoons, but not for two early season typhoons and the late season Dolphin. Four strong tropical storms were predicted consistently over Week-1 through Week-4, as was one weak tropical storm. Two other weak tropical storms, three tropical cyclones that developed from precursor baroclinic systems, and three other tropical depressions were not predicted on intraseasonal timescales. At least for the strongest tropical cyclones during the peak season, the ECMWF 32-day ensemble provides guidance of formation and tracks on 10-30 day timescales.

The Response of Mid-Latitude Ionospheric TEC to Geomagnetic Storms and Solar Flares

NASA Astrophysics Data System (ADS)

Huang, Z.; Roussel-Dupre, R.

2004-12-01

The effects of geomagnetic storms and solar flares on the ionosphere are manifested as large magnitude sudden fluctuations in the Total Electron Content (TEC). In this study, the broadband VHF signal (30-100MHz) data from the Los Alamos Portable Pulser (LAPP) received by the FORTE (Fast Onboard Recording of Transient Events) satellite during the period of 1997-2002 are used to investigate the mean TEC variation response to geomagnetic storm. A total of 14 geomagnetic storms are selected where FORTE-LAPP data are available to derive average TECs during extended storm-time and non-storm time for a given storm. The variations in the ionospheric TECs at Los Alamos, New Mexico are investigated for the 14 selected geomagnetic storms. In most cases (12 out of 14), we see overall enhancements in TEC as a result of geomagnetic storm impact at Los Alamos. The relative enhancements in TEC at Los Alamos due to a geomagnetic storm can reach as high as 3-fold of the normal TEC values. The overall absolute enhancements in TEC at Los Alamos are up to about 30 TECU. The magnitude of TEC enhancements is diversified over all storm categories without a clean-cut relationship between the storm intensity and the TEC enhancement. The mean TEC variation response to geomagnetic storm can be complicated when several consecutive storms occurred in a row and a net TEC reduction may be seen. Data of continuous GPS TEC measurements are collected at a 1-minute time resolution during July 2004 when 5 X-class solar flares occurred from two Allen Osborne Associates ICS-4000Z GPS receivers mounted at the Physics Building at Los Alamos National Laboratory. In detecting effects of solar flares on the ionospheric TEC, we apply appropriate filtering to remove the linear trend of TEC and a coherent processing of TEC variations simultaneously for all the visible GPS satellites in a given time interval. The responses of ionospheric TEC at minute time scale to these powerful impulsive solar flares are investigated. The onset time of the ionospheric response and the magnitude of the TEC fluctuations and its time derivative are examined along with their relationships with the solar flux characteristics, duration of the flare and location of the flare on the Sun, X-ray emission variations during the flares, and local time of the flare occurrence.

On the mid-latitude ionospheric storm association with intense geomagnetic storms

NASA Astrophysics Data System (ADS)

Okpala, Kingsley Chukwudi; Ogbonna, Chinasa Edith

2018-04-01

The bulk association between ionospheric storms and geomagnetic storms has been studied. Hemispheric features of seasonal variation of ionospheric storms in the mid-latitude were also investigated. 188 intense geomagnetic storms (Dst ≤ 100 nT) that occurred during solar cycles 22 and 23 were considered, of which 143 were observed to be identified with an ionospheric storm. Individual ionospheric storms were identified as maximum deviations of the F2 layer peak electron density from quiet time values. Only ionospheric storms that could clearly be associated with the peak of a geomagnetic storm were considered. Data from two mid-latitude ionosonde stations; one in the northern hemisphere (i.e. Moscow) and the other in the southern hemisphere (Grahamstown) were used to study ionospheric conditions at the time of the individual geomagnetic storms. Results show hemispheric and latitudinal differences in the intensity and nature of ionospheric storms association with different types of geomagnetic storms. These results are significant for our present understanding of the mechanisms which drive the changes in electron density during different types of ionospheric storms.

A Study of Ionospheric Storm Association with Intense Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Okpala, K. C.

2017-12-01

The bulk association between ionospheric storms and geomagnetic storms have been studied. Hemispheric features of seasonal variation of ionospheric storms in the mid-latitude were also investigated. 188 intense geomagnetic storms (Dst ≤100nT) that occurred during solar cycle 22 and 23 were considered, of which 143 were observed to be identified with an ionospheric storm. Individual ionospheric storms were identified as maximum deviations of the F2 layer peak electron density from quiet time values. Only ionospheric storms that could clearly be associated with the peak of a geomagnetic storms were considered. Data from two mid-latitude ionosonde stations; one in the northern hemisphere (i.e Moscow) and the other in the southern hemisphere (Grahamstown) were used to study ionospheric condition at the time of the individual geomagnetic storms. Results show hemispheric and latitudinal differences in the intensity and nature of ionospheric storms association with different types of geomagnetic storms. These results are significant for our present understanding of the mechanisms which drive the changes in electron density during different types of ionospheric storms.

Restoration of STORM images from sparse subset of localizations (Conference Presentation)

NASA Astrophysics Data System (ADS)

Moiseev, Alexander A.; Gelikonov, Grigory V.; Gelikonov, Valentine M.

2016-02-01

To construct a Stochastic Optical Reconstruction Microscopy (STORM) image one should collect sufficient number of localized fluorophores to satisfy Nyquist criterion. This requirement limits time resolution of the method. In this work we propose a probabalistic approach to construct STORM images from a subset of localized fluorophores 3-4 times sparser than required from Nyquist criterion. Using a set of STORM images constructed from number of localizations sufficient for Nyquist criterion we derive a model which allows us to predict the probability for every location to be occupied by a fluorophore at the end of hypothetical acquisition, having as an input parameters distribution of already localized fluorophores in the proximity of this location. We show that probability map obtained from number of fluorophores 3-4 times less than required by Nyquist criterion may be used as superresolution image itself. Thus we are able to construct STORM image from a subset of localized fluorophores 3-4 times sparser than required from Nyquist criterion, proportionaly decreasing STORM data acquisition time. This method may be used complementary with other approaches desined for increasing STORM time resolution.

Increasing large scale windstorm damage in Western, Central and Northern European forests, 1951-2010

NASA Astrophysics Data System (ADS)

Gregow, H.; Laaksonen, A.; Alper, M. E.

2017-04-01

Using reports of forest losses caused directly by large scale windstorms (or primary damage, PD) from the European forest institute database (comprising 276 PD reports from 1951-2010), total growing stock (TGS) statistics of European forests and the daily North Atlantic Oscillation (NAO) index, we identify a statistically significant change in storm intensity in Western, Central and Northern Europe (17 countries). Using the validated set of storms, we found that the year 1990 represents a change-point at which the average intensity of the most destructive storms indicated by PD/TGS > 0.08% increased by more than a factor of three. A likelihood ratio test provides strong evidence that the change-point represents a real shift in the statistical behaviour of the time series. All but one of the seven catastrophic storms (PD/TGS > 0.2%) occurred since 1990. Additionally, we detected a related decrease in September-November PD/TGS and an increase in December-February PD/TGS. Our analyses point to the possibility that the impact of climate change on the North Atlantic storms hitting Europe has started during the last two and half decades.

Increasing large scale windstorm damage in Western, Central and Northern European forests, 1951–2010

PubMed Central

Gregow, H.; Laaksonen, A.; Alper, M. E.

2017-01-01

Using reports of forest losses caused directly by large scale windstorms (or primary damage, PD) from the European forest institute database (comprising 276 PD reports from 1951–2010), total growing stock (TGS) statistics of European forests and the daily North Atlantic Oscillation (NAO) index, we identify a statistically significant change in storm intensity in Western, Central and Northern Europe (17 countries). Using the validated set of storms, we found that the year 1990 represents a change-point at which the average intensity of the most destructive storms indicated by PD/TGS > 0.08% increased by more than a factor of three. A likelihood ratio test provides strong evidence that the change-point represents a real shift in the statistical behaviour of the time series. All but one of the seven catastrophic storms (PD/TGS > 0.2%) occurred since 1990. Additionally, we detected a related decrease in September–November PD/TGS and an increase in December–February PD/TGS. Our analyses point to the possibility that the impact of climate change on the North Atlantic storms hitting Europe has started during the last two and half decades. PMID:28401947

High-Latitude Topside Ionospheric Vertical Electron Density Profile Changes in Response to Large Magnetic Storms

NASA Technical Reports Server (NTRS)

Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

2016-01-01

Large magnetic-storm-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic storm (Dst -100nT). Storms where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than storms with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all storms, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial andor temporal Ne(h) changes were often observed during Dst minimum and during the storm recovery phase. The storm-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere storm-induced enhancements and depletions were typically considerably less with depletions observed during summer nighttime conditions and enhancements during summer daytime and fall nighttime conditions.

High-latitude topside ionospheric vertical electron density profile changes in response to large magnetic storms

NASA Astrophysics Data System (ADS)

Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

2016-05-01

Large magnetic-storm-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic storm (Dst < -100 nT). Storms where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than storms with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all storms, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial and/or temporal Ne(h) changes were often observed during Dst minimum and during the storm recovery phase. The storm-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100 km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere storm-induced enhancements and depletions were typically considerably less with depletions observed during summer nighttime conditions and enhancements during summer daytime and fall nighttime conditions.

Evaluation of the NCEP CFSv2 45-day Forecasts for Predictability of Intraseasonal Tropical Storm Activities

NASA Astrophysics Data System (ADS)

Schemm, J. E.; Long, L.; Baxter, S.

2013-12-01

Evaluation of the NCEP CFSv2 45-day Forecasts for Predictability of Intraseasonal Tropical Storm Activities Jae-Kyung E. Schemm, Lindsey Long and Stephen Baxter Climate Prediction Center, NCEP/NWS/NOAA Predictability of intraseasonal tropical storm (TS) activities is assessed using the 1999-2010 CFSv2 hindcast suite. Weekly TS activities in the CFSv2 45-day forecasts were determined using the TS detection and tracking method devised by Carmago and Zebiak (2002). The forecast periods are divided into weekly intervals for Week 1 through Week 6, and also the 30-day mean. The TS activities in those intervals are compared to the observed activities based on the NHC HURDAT and JTWC Best Track datasets. The CFSv2 45-day hindcast suite is made of forecast runs initialized at 00, 06, 12 and 18Z every day during the 1999 - 2010 period. For predictability evaluation, forecast TS activities are analyzed based on 20-member ensemble forecasts comprised of 45-day runs made during the most recent 5 days prior to the verification period. The forecast TS activities are evaluated in terms of the number of storms, genesis locations and storm tracks during the weekly periods. The CFSv2 forecasts are shown to have a fair level of skill in predicting the number of storms over the Atlantic Basin with the temporal correlation scores ranging from 0.73 for Week 1 forecasts to 0.63 for Week 6, and the average RMS errors ranging from 0.86 to 1.07 during the 1999-2010 hurricane season. Also, the forecast track density distribution and false alarm statistics are compiled using the hindcast analyses. In real-time applications of the intraseasonal TS activity forecasts, the climatological TS forecast statistics will be used to make the model bias corrections in terms of the storm counts, track distribution and removal of false alarms. An operational implementation of the weekly TS activity prediction is planned for early 2014 to provide an objective input for the CPC's Global Tropical Hazards Outlooks.

Modelling and in-situ measurements of intense currents during a winter storm in the Gulf of Aigues-Mortes (NW Mediterranean Sea)

NASA Astrophysics Data System (ADS)

Michaud, Héloïse; Leredde, Yann; Estournel, Claude; Berthebaud, Éric; Marsaleix, Patrick

2013-09-01

While oceanic circulation in the Gulf of Lion (GoL) has often been studied in calm weather or with northerly winds (Tramontane or Mistral) through observations and numerical circulation models, few studies have focused on southeasterly storm events. Yet, correct representation of the circulation during storms is crucial if the suspension of sediments is to be correctly modelled throughout the Gulf. The purpose of this paper is to describe the hydrodynamics in the Gulf of Aigues-Mortes (NW of the GoL) during the storm of 18 February 2007 by using a set of data from an ADCP station placed at a depth of 65 m on the sea bed off the coast at Sète, supplemented by the ocean circulation model SYMPHONIE. This storm was characterized by a moderate south-easterly wind (15 m . s-1) and waves of up to 5 m of significant height at its apex. At the ADCP, strong currents of up to 0.8 m . s-1 near the surface and 0.5 m . s-1 near the bottom were recorded, parallel to the coast, flowing towards the south-west. The simulated currents were widely underestimated, even taking the effect of waves into account in the model. It was suspected that the representation of the wind in the atmospheric model was an underestimation. A new simulation was therefore run with an arbitrarily chosen stronger wind and its results were in much better agreement with the measurements. A simplified theoretical analysis successfully isolated the wind-induced processes, responsible for the strong currents measured during the apex and the strong vertical shear that occurred at the beginning of the storm. These processes were: 1/ the barotropic geostrophic current induced by a wind parallel to the coast and 2/ the Ekman spiral. The duration of the storm (about 36 h at the apex) explains the continuous increase of the current as predicted by the theory. The frictionally induced Ekman transport explains the current shear in the surface layer in the rising stage of the storm, and the addition of high waves and strong wind at the apex is more in favour of strong vertical mixing in the surface layer.

Characterization of Mediterranean hail-bearing storms using an operational polarimetric X-band radar

NASA Astrophysics Data System (ADS)

Vulpiani, G.; Baldini, L.; Roberto, N.

2015-11-01

This work documents the effective use of X-band radar observations for monitoring severe storms in an operational framework. Two severe hail-bearing Mediterranean storms that occurred in 2013 in southern Italy, flooding two important Sicilian cities, are described in terms of their polarimetric radar signatures and retrieved rainfall fields. The X-band dual-polarization radar operating inside the Catania airport (Sicily, Italy), managed by the Italian Department of Civil Protection, is considered here. A suitable processing is applied to X-band radar measurements. The crucial procedural step relies on the differential phase processing, being preparatory for attenuation correction and rainfall estimation. It is based on an iterative approach that uses a very short-length (1 km) moving window, allowing proper capture of the observed high radial gradients of the differential phase. The parameterization of the attenuation correction algorithm, which uses the reconstructed differential phase shift, is derived from electromagnetic simulations based on 3 years of drop size distribution (DSD) observations collected in Rome (Italy). A fuzzy logic hydrometeor classification algorithm was also adopted to support the analysis of the storm characteristics. The precipitation field amounts were reconstructed using a combined polarimetric rainfall algorithm based on reflectivity and specific differential phase. The first storm was observed on 21 February when a winter convective system that originated in the Tyrrhenian Sea, marginally hit the central-eastern coastline of Sicily, causing a flash flood in Catania. Due to an optimal location (the system is located a few kilometers from the city center), it was possible to retrieve the storm characteristics fairly well, including the amount of rainfall field at the ground. Extemporaneous signal extinction, caused by close-range hail core causing significant differential phase shift in a very short-range path, is documented. The second storm, on 21 August 2013, was a summer mesoscale convective system that originated from a Mediterranean low pressure system lasting a few hours that eventually flooded the city of Syracuse. The undergoing physical process, including the storm dynamics, is inferred by analyzing the vertical sections of the polarimetric radar measurements. The high registered amount of precipitation was fairly well reconstructed, although with a trend toward underestimation at increasing distances. Several episodes of signal extinction were clearly manifested during the mature stage of the observed supercells.

Acid-rain induced changes in streamwater quality during storms on Catoctin Mountain, Maryland

USGS Publications Warehouse

Rice, Karen C.; Bricker, O.P.

1992-01-01

Catoctin Mountain receives some of the most acidic (lowest pH) rain in the United States. In 1990, the U.S. Geological Survey (USGS), in cooperation with the Maryland Department of the Environment (MDE) and the Maryland Department of Natural Resources (DNR), began a study of the effects of acid rain on the quality of streamwater on the part of Catoctin Mountain within Cunningham Falls State Park, Maryland (fig. 1). Samples of precipitation collected on the mountain by the USGS since 1982 have been analyzed for acidity and concentration of chemical constituents. During 1982-91, the volume-weighted average pH of precipitation was 4.2. (Volume weighting corrects for the effect of acids being washed out of the atmosphere at the beginning of rainfall). The pH value is measured on a logarithmic scale, which means that for each whole number change, the acidity changes by a factor of 10. Thus rain with a pH of 4.2 is more than 10 times as acidic as uncontaminated rain, which has a pH of about 5.6. The acidity of rain during several rainstorms on Catoctin Mountain was more than 100 times more acidic than uncontaminated rain.

A new ionospheric storm scale based on TEC and foF2 statistics

NASA Astrophysics Data System (ADS)

Nishioka, Michi; Tsugawa, Takuya; Jin, Hidekatsu; Ishii, Mamoru

2017-01-01

In this paper, we propose the I-scale, a new ionospheric storm scale for general users in various regions in the world. With the I-scale, ionospheric storms can be classified at any season, local time, and location. Since the ionospheric condition largely depends on many factors such as solar irradiance, energy input from the magnetosphere, and lower atmospheric activity, it had been difficult to scale ionospheric storms, which are mainly caused by solar and geomagnetic activities. In this study, statistical analysis was carried out for total electron content (TEC) and F2 layer critical frequency (foF2) in Japan for 18 years from 1997 to 2014. Seasonal, local time, and latitudinal dependences of TEC and foF2 variabilities are excluded by normalizing each percentage variation using their statistical standard deviations. The I-scale is defined by setting thresholds to the normalized numbers to seven categories: I0, IP1, IP2, IP3, IN1, IN2, and IN3. I0 represents a quiet state, and IP1 (IN1), IP2 (IN2), and IP3 (IN3) represent moderate, strong, and severe positive (negative) storms, respectively. The proposed I-scale can be used for other locations, such as polar and equatorial regions. It is considered that the proposed I-scale can be a standardized scale to help the users to assess the impact of space weather on their systems.

Predicting forest road surface erosion and storm runoff from high-elevation sites

Treesearch

J. M. Grace III

2017-01-01

Forest roads are a concern in management because they represent areas of elevated risks associated with soil erosion and storm runoff connectivity to stream systems. Storm runoff emanating from forest roads and their connectivity to downslope resources can be influenced by a myriad of factors, including storm characteristics, management practices, and the interaction...

Climate Change Implications and Use of Early Warning Systems for Global Dust Storms

NASA Astrophysics Data System (ADS)

Harriman, L.

2014-12-01

Increased changes in land cover and global climate have led to increased frequency and/or intensity of dust storms in some regions of the world. Early detection and warning of dust storms, in conjunction with effective and widespread information broadcasts, will be essential to the prevention and mitigation of future risks and impacts to people and the environment. Since frequency and intensity of dust storms can vary from region to region, there is a demonstrated need for more research to be conducted over longer periods of time to analyze trends of dust storm events [1]. Dust storms impact their origin area, but also land, water and people a great distance away from where dust finally settles [2, 3]. These transboundary movements and accompanying impacts further warrant the need for global collaboration to help predict the onset, duration and path of a dust storm. Early warning systems can help communicate when a dust storm is occurring, the projected intensity of the dust storm and its anticipated physical impact over a particular geographic area. Development of regional dust storm models, such as CUACE/Dust for East Asia, and monitoring networks, like the Sand and Dust Storm Warning Network operated by the World Meteorological Organization, and the use of remote sensing and satellite imagery derived products [4], including MODIS, are currently being incorporated into early warning and monitoring initiatives. However, to increase future certainty of impacts of dust storms on vulnerable populations and ecosystems, more research is needed to analyze the influences of human activities, seasonal variations and long-term climatic patterns on dust storm generation, movement and impact. Sources: [1] Goudie, A.S. (2009), Dust storms: recent developments, J Environ. Manage., 90. [2] Lee, H., and Liu, C. (2004), Coping with dust storm events: information, impacts, and policymaking in Taiwan, TAO, 15(5). [3] Marx, S.K., McGowan, H.A., and Balz, K.S. (2009), Long-range dust transport from eastern Australia: a proxy for Holocene aridity and ENSO-type climate variability, Earth Planet Sci. Lett., 282. [4] Kimura, R. (2012), Factors contributing to dust storms in source regions producing the yellow-sand phenomena observed in Japan from 1993 to 2002, J. Arid Environ. 80

Multispacecraft Observations and Modeling of the 22/23 June 2015 Geomagnetic Storm

NASA Technical Reports Server (NTRS)

Reiff, P. H.; Daou, A. G.; Sazykin, S. Y.; Nakamura, R.; Hairston, M. R.; Coffey, V.; Chandler, M. O.; Anderson, B. J.; Russell, C. T.; Welling, D.;

Acceleration and loss of relativistic electrons during small geomagnetic storms.

PubMed

Anderson, B R; Millan, R M; Reeves, G D; Friedel, R H W

2015-12-16

Past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms ( D s t  > -50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result in flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.

Reduction of coherence of the human brain electric potentials

NASA Astrophysics Data System (ADS)

Novik, Oleg; Smirnov, Fedor

Plenty of technological processes are known to be damaged by magnetic storms. But technology is controlled by men and their functional systems may be damaged as well. We are going to consider the electro-neurophysiological aspect of the general problem: men surrounded by physical fields including ones of cosmic origination. Magnetic storms’ influence had been observed for a group of 13 students (practically healthy girls and boys from 18 to 23 years old, Moscow). To control the main functional systems of the examinees, their electroencephalograms (EEG) were being registered along with electrocardiograms, respiratory rhythms, arterial blood pressure and other characteristics during a year. All of these characteristics, save for the EEG, were within the normal range for all of the examinees during measurements. According to the EEG investigations by implementation of the computer proof-reading test in absence of magnetic storms, the values of the coherence function of time series of the theta-rhythm oscillations (f = 4 - 7.9 Hz, A = 20 μV) of electric potentials of the frontal-polar and occipital areas of the head belong to the interval [0.3, 0.8] for all of the students under investigation. (As the proof-reading test, it was necessary to choose given symbols from a random sequence of ones demonstrated at a monitor and to enter the number of the symbols discovered in a computer. Everyone was known that the time for determination of symbols is unlimited. On the other hand, nobody was known that the EEG and other registrations mentioned are connected with electromagnetic geophysical researches and geomagnetic storms). Let us formulate the main result: by implementation of the same test during a magnetic storm, 5 ≤ K ≤ 6, or no later then 24 hours after its beginning (different types of moderate magnetic storms occurred, the data of IZMIRAN were used), the values of the theta-rhythm frontal - occipital coherence function of all of the students of the group under consideration decreased by a factor of two or more, including the zero coherence function value. The similar result was obtained for another basic low-frequency electro-neurophysiological rhythm delta (f = 0.5 - 3.9 Hz, A = 20 μV). The usual coherence function values from the interval [0.3, 0.8] were being registered, typically, about 48 hours after the magnetic storm end. The result about decreasing of the coherence of the brain low frequency bioelectric oscillations under a magnetic storm influence was obtained by two methods: 1) comparison of the time series of bioelectric oscillations of a given person without a magnetic storm and under its influence; 2) comparison of two sets of time series of oscillations: a) the set A of time series measured without a magnetic storm and b) the set B of time series measured under its influence, regardless to an individual. Surely, the total number of the EEGs available for the investigation by the set’s approach, i.e. without personification, is more than the number of the EEGs available by the individual approach because there were ones investigated without a magnetic storm only as well as ones investigated under its influence only. By the EEG measurements with closed or open eyes, but without a functional load on the brain in the form of the proof-reading test, a distinctive decrease of the coherence function was not observed during a magnetic storm as well as for pairs of points from other parts of the head (see above) or other rhythms.

An examination of extratropical cyclone response to changes in baroclinicity and temperature in an idealized environment

NASA Astrophysics Data System (ADS)

Tierney, Gregory; Posselt, Derek J.; Booth, James F.

2018-02-01

The dynamics and precipitation in extratropical cyclones (ETCs) are known to be sensitive to changes in the cyclone environment, with increases in bulk water vapor and baroclinicity both leading to increases in storm strength and precipitation. Studies that demonstrate this sensitivity have commonly varied either the cyclone moisture or baroclinicity, but seldom both. In a changing climate, in which the near-surface equator to pole temperature gradient may weaken while the bulk water vapor content of the atmosphere increases, it is important to understand the relative response of ETC strength and precipitation to changes in both factors simultaneously. In this study, idealized simulations of ETC development are conducted in a moist environment using a model with a full suite of moist physics parameterizations. The bulk temperature (and water vapor content) and baroclinicity are systematically varied one at a time, then simultaneously, and the effect of these variations on the storm strength and precipitation is assessed. ETC intensity exhibits the well-documented response to changes in baroclinicity, with stronger ETCs forming in higher baroclinicity environments. However, increasing water vapor content produces non-monotonic changes in storm strength, in which storm intensity first increases with increasing environmental water vapor, then decreases above a threshold value. Examination of the storm geographic extent indicates cyclone size also decreases above a threshold value of bulk environmental temperature (and water vapor). Decrease in storm size is concomitant with an increase in the convective fraction of precipitation and a shift in the vertical distribution of latent heating. The results indicate the existence of at least two regimes for ETC development, each of which exhibit significantly different distributions of PV due to differences in timing and location of convective heating.

The influence of topography on vertical velocity of air in relation to severe storms near the Southern Andes Mountains

NASA Astrophysics Data System (ADS)

de la Torre, A.; Pessano, H.; Hierro, R.; Santos, J. R.; Llamedo, P.; Alexander, P.

2015-04-01

On the basis of 180 storms which took place between 2004 and 2011 over the province of Mendoza (Argentina) near to the Andes Range at southern mid-latitudes, we consider those registered in the northern and central crop areas (oases). The regions affected by these storms are currently protected by an operational hail mitigation project. Differences with previously reported storms detected in the southern oasis are highlighted. Mendoza is a semiarid region situated roughly between 32S and 37S at the east of the highest Andes top. It forms a natural laboratory where different sources of gravity waves, mainly mountain waves, occur. In this work, we analyze the effects of flow over topography generating mountain waves and favoring deep convection. The joint occurrence of storms with hail production and mountain waves is determined from mesoscale numerical simulations, radar and radiosounding data. In particular, two case studies that properly represent diverse structures observed in the region are considered in detail. A continuous wavelet transform is applied to each variable and profile to detect the main oscillation modes present. Simulated temperature profiles are validated and compared with radiosounding data. Each first radar echo, time and location are determined. The necessary energy to lift a parcel to its level of free convection is tested from the Convective Available Potential Energy and Convection Inhibition. This last parameter is compared against the mountain waves' vertical kinetic energy. The time evolution and vertical structure of vertical velocity and equivalent potential temperature suggest in both cases that the detected mountain wave amplitudes are able to provide the necessary energy to lift the air parcel and trigger convection. A simple conceptual scheme linking the dynamical factors taking place before and during storm development is proposed.

Regional and seasonal estimates of fractional storm coverage based on station precipitation observations

NASA Technical Reports Server (NTRS)

Gong, Gavin; Entekhabi, Dara; Salvucci, Guido D.

1994-01-01

Simulated climates using numerical atmospheric general circulation models (GCMs) have been shown to be highly sensitive to the fraction of GCM grid area assumed to be wetted during rain events. The model hydrologic cycle and land-surface water and energy balance are influenced by the parameter bar-kappa, which is the dimensionless fractional wetted area for GCM grids. Hourly precipitation records for over 1700 precipitation stations within the contiguous United States are used to obtain observation-based estimates of fractional wetting that exhibit regional and seasonal variations. The spatial parameter bar-kappa is estimated from the temporal raingauge data using conditional probability relations. Monthly bar-kappa values are estimated for rectangular grid areas over the contiguous United States as defined by the Goddard Institute for Space Studies 4 deg x 5 deg GCM. A bias in the estimates is evident due to the unavoidably sparse raingauge network density, which causes some storms to go undetected by the network. This bias is corrected by deriving the probability of a storm escaping detection by the network. A Monte Carlo simulation study is also conducted that consists of synthetically generated storm arrivals over an artificial grid area. It is used to confirm the bar-kappa estimation procedure and to test the nature of the bias and its correction. These monthly fractional wetting estimates, based on the analysis of station precipitation data, provide an observational basis for assigning the influential parameter bar-kappa in GCM land-surface hydrology parameterizations.

Mediterranean Cyclones in a changing climate. First statistical results

NASA Astrophysics Data System (ADS)

Tous, M.; Genoves, A.; Campins, J.; Picornell, M. A.; Jansa, A.; Mizuta, R.

2009-09-01

The Mediterranean storms play an important role in weather and climate. Their influence in determining the local weather is known; heavy precipitation systems and strong wind cases are often related to the presence of a cyclone in the Mediterranean. From a large-scale point of view, the Mediterranean storm track has importance in the vertical and horizontal transfers of heat and water vapour towards the Eastern regions. For all of these reasons, any future change related to the intensity, frequency or tracks of these storms can be important for both the local weather and local climate, at least, in the countries around the basin. The Mediterranean cyclones constitute a study subject of increasing interest. Some climatologies from long series of re-analyses, like ERA15, NCEP/NCAR and ERA40, or from operational and high resolution analysis systems, like HIRLAM_INM and ECMWF, have allowed to define the main characteristics of these storms. Generally speaking, the Mediterranean storms have the characteristics of extratropical storms, showing smaller sizes and shorter life cycles than those ones developed in other maritime areas of the world. Moreover, the influence of the land areas and high mountains around the basin and the large-scale heat releases have been revealed as key factors for understanding their genesis and rates of development. In spite of the fact that probably the existing automatic procedures include some large scale assumptions, which may not the best for the correct detection and tracking the Mediterranean storms, these procedures can provide a first and almost necessary step, from a statistical/climatological point of view, specially taking into account both the current resolution of the existent global re-analysis series and global climatic models and the state-of-the art about Mediterranean cyclones. A cyclone detection and tracking procedure, originally designed for the description of Mediterranean storms, has been applied to the low resolution (1.5 degrees lat-lon) outputs of the JMA-GSM climate general circulation model. Preliminary results are here presented. Two different periods have been analysed. The first period, covering 1979-2002 has been compared with the previously computed ERA-40 climatology of cyclones. Results agree reasonably well with those obtained from ERA-40, providing confidence to the current climate simulation of JMA-GSM. Once validated the model from the perspective of cyclonic climatology under current climate conditions, the same procedure is applied to a scenario period (2075-2099) to investigate possible changes in cyclonic activity linked to climate change.

Observations of storm morphodynamics using Coastal Lidar and Radar Imaging System (CLARIS): Importance of wave refraction and dissipation over complex surf-zone morphology at a shoreline erosional hotspot

NASA Astrophysics Data System (ADS)

Brodie, Katherine L.

Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be useful to both emergency managers and homeowners preparing for an approaching storm. Unfortunately, research on the impact of a storm to the beach has mainly been derived from "pre" and "post" storm surveys of beach topography and nearshore bathymetry during calm conditions. This has created a lack of data during storms from which to ground-truth model predictions and test hypotheses that explain variations in erosion along a coastline. We have developed Coastal Lidar and Radar Imaging System (CLARIS), a mobile system that combines a terrestrial scanning laser and an X-band marine radar system using precise motion and location information. CLARIS can operate during storms, measuring beach topography, nearshore bathymetry (from radar-derived wave speed measurements), surf-zone wave parameters, and maximum water levels remotely. In this dissertation, we present details on the development, design, and testing of CLARIS and then use CLARIS to observe a 10 km section of coastline in Kitty Hawk and Kill Devil Hills on the Outer Banks of North Carolina every 12 hours during a Nor'Easter (peak wave height in 8 m of water depth = 3.4 m). High decadal rates of shoreline change as well as heightened erosion during storms have previously been documented to occur within the field site. In addition, complex bathymetric features that traverse the surf-zone into the nearshore are present along the southern six kilometers of the field site. In addition to the CLARIS observations, we model wave propagation over the complex nearshore bathymetry for the same storm event. Data reveal that the complex nearshore bathymetry is mirrored by kilometer scale undulations in the shoreline, and that both morphologies persist during storms, contrary to common observations of shoreline and surf-zone linearization by large storm waves. We hypothesize that wave refraction over the complex nearshore bathymetry forces flow patterns which may enhance or stabilize the shoreline and surf-zone morphology during storms. In addition, our semi-daily surveys of the beach indicate that spatial and temporal patterns of erosion are strongly correlated to the steepness of the waves. Along more than half the study site, fifty percent or more of the erosion that occurred during the first 12 hours of the storm was recovered within 24 hours of the peak of the storm as waves remained large (>2.5 m), but transitioned to long period swell. In addition, spatial variations in the amount of beach volume change during the building portion of the storm were strongly correlated with observed wave dissipation within the inner surf zone, as opposed to predicted inundation elevations or alongshore variations in wave height.

Can we trust climate models to realistically represent severe European windstorms?

NASA Astrophysics Data System (ADS)

Trzeciak, Tomasz M.; Knippertz, Peter; Owen, Jennifer S. R.

2014-05-01

Despite the enormous advances made in climate change research, robust projections of the position and the strength of the North Atlantic stormtrack are not yet possible. In particular with respect to damaging windstorms, this incertitude bears enormous risks to European societies and the (re)insurance industry. Previous studies have addressed the problem of climate model uncertainty through statistical comparisons of simulations of the current climate with (re-)analysis data and found that there is large disagreement between different climate models, different ensemble members of the same model and observed climatologies of intense cyclones. One weakness of such statistical evaluations lies in the difficulty to separate influences of the climate model's basic state from the influence of fast processes on the development of the most intense storms. Compensating effects between the two might conceal errors and suggest higher reliability than there really is. A possible way to separate influences of fast and slow processes in climate projections is through a "seamless" approach of hindcasting historical, severe storms with climate models started from predefined initial conditions and run in a numerical weather prediction mode on the time scale of several days. Such a cost-effective case-study approach, which draws from and expands on the concepts from the Transpose-AMIP initiative, has recently been undertaken in the SEAMSEW project at the University of Leeds funded by the AXA Research Fund. Key results from this work focusing on 20 historical storms and using different lead times and horizontal and vertical resolutions include: (a) Tracks are represented reasonably well by most hindcasts. (b) Sensitivity to vertical resolution is low. (c) There is a systematic underprediction of cyclone depth for a coarse resolution of T63, but surprisingly no systematic bias is found for higher-resolution runs using T127, showing that climate models are in fact able to represent the storm dynamics well, if given the correct initial conditions. Combined with a too low number of deep cyclones in many climate models, this points too an insufficient number of storm-prone initial conditions in free-running climate runs. This question will be addressed in future work.

Statistical modeling of storm-level Kp occurrences

USGS Publications Warehouse

Remick, K.J.; Love, J.J.

2006-01-01

We consider the statistical modeling of the occurrence in time of large Kp magnetic storms as a Poisson process, testing whether or not relatively rare, large Kp events can be considered to arise from a stochastic, sequential, and memoryless process. For a Poisson process, the wait times between successive events occur statistically with an exponential density function. Fitting an exponential function to the durations between successive large Kp events forms the basis of our analysis. Defining these wait times by calculating the differences between times when Kp exceeds a certain value, such as Kp ??? 5, we find the wait-time distribution is not exponential. Because large storms often have several periods with large Kp values, their occurrence in time is not memoryless; short duration wait times are not independent of each other and are often clumped together in time. If we remove same-storm large Kp occurrences, the resulting wait times are very nearly exponentially distributed and the storm arrival process can be characterized as Poisson. Fittings are performed on wait time data for Kp ??? 5, 6, 7, and 8. The mean wait times between storms exceeding such Kp thresholds are 7.12, 16.55, 42.22, and 121.40 days respectively.

Performance of Precipitation Algorithms During IPHEx and Observations of Microphysical Characteristics in Complex Terrain

NASA Astrophysics Data System (ADS)

Erlingis, J. M.; Gourley, J. J.; Kirstetter, P.; Anagnostou, E. N.; Kalogiros, J. A.; Anagnostou, M.

2015-12-01

An Intensive Observation Period (IOP) for the Integrated Precipitation and Hydrology Experiment (IPHEx), part of NASA's Ground Validation campaign for the Global Precipitation Measurement Mission satellite took place from May-June 2014 in the Smoky Mountains of western North Carolina. The National Severe Storms Laboratory's mobile dual-pol X-band radar, NOXP, was deployed in the Pigeon River Basin during this time and employed various scanning strategies, including more than 1000 Range Height Indicator (RHI) scans in coordination with another radar and research aircraft. Rain gauges and disdrometers were also positioned within the basin to verify precipitation estimates and estimation of microphysical parameters. The performance of the SCOP-ME post-processing algorithm on NOXP data is compared with real-time and near real-time precipitation estimates with varying spatial resolutions and quality control measures (Stage IV gauge-corrected radar estimates, Multi-Radar/Multi-Sensor System Quantitative Precipitation Estimates, and CMORPH satellite estimates) to assess the utility of a gap-filling radar in complex terrain. Additionally, the RHI scans collected in this IOP provide a valuable opportunity to examine the evolution of microphysical characteristics of convective and stratiform precipitation as they impinge on terrain. To further the understanding of orographically enhanced precipitation, multiple storms for which RHI data are available are considered.

NARX neural network Prediction of SYMH and ASYH indices for geomagnetic storms of solar cycle 24 including recent St. Patrick's day, 2015 storm

NASA Astrophysics Data System (ADS)

Bhaskar, A. T.; Vichare, G.

2017-12-01

Here, an attempt is made to develop a prediction model for SYMH and ASYH geomagnetic indices using Artificial Neural Network (ANN). SYMH and ASYH indices represent longitudinal symmetric and asymmetric component of the ring current. The ring current state depends on its past conditions therefore, it is necessary to consider its history for prediction. To account this effect Nonlinear Autoregressive Network with eXogenous inputs (NARX) is implemented. This network considers input history of 30 minutes and output feedback of 120 minutes. Solar wind parameters mainly velocity, density and interplanetary magnetic field are used as inputs. SYMH and ASYH indices during geomagnetic storms of 1998-2013, having minimum SYMH <-85 nT are used as the target for training two independent networks. We present the prediction of SYMH and ASYH indices during 9 geomagnetic storms of solar cycle 24 including the recent largest storm occurred on St. Patrick's day, 2015. The present prediction model reproduces the entire time profile of SYMH and ASYH indices along with small variations of 10-30 minutes to good extent within noise level, indicating significant contribution of interplanetary sources and past state of the magnetosphere. However, during the main phase of major storms, residuals (observed-modeled) are found to be large, suggesting influence of internal factors such as magnetospheric processes.

Characteristics of the overflow pollution of storm drains with inappropriate sewage entry.

PubMed

Yin, Hailong; Lu, Yi; Xu, Zuxin; Li, Huaizheng; Schwegler, Benedict R

2017-02-01

To probe the overflow pollution of separate storm drains with inappropriate sewage entries, in terms of the relationship between sewage entries and the corresponding dry-weather and wet-weather overflow, the monitoring activities were conducted in a storm drainage system in the Shanghai downtown area (374 ha). In this study site, samples from inappropriately entered dry-weather sewage and the overflow due to storm pumps operation on dry-weather and wet-weather days were collected and then monitored for six water quality constituents. It was found that overflow concentrations of dry-weather period could be higher than those of wet-weather period; under wet-weather period, the overflow concentrations of storm drains were close to or even higher than that of combined sewers. Relatively strong first flush mostly occurred under heavy rain that satisfied critical rainfall amount, maximum rainfall intensity, and maximum pumping discharge, while almost no first flush effect or only weak first flush effect was found for the other rainfall events. Such phenomenon was attributed to lower in-line pipe storage as compared to that of the combined sewers, and serious sediment accumulation within the storm pipes due to sewage entry. For this kind of system, treating a continuous overflow rate is a better strategy than treating the maximum amount of early part of the overflow. Correcting the key inappropriate sewage entries into storm drains should also be focused.

Testing Taylor’s hypothesis in Amazonian rainfall fields during the WETAMC/LBA experiment

NASA Astrophysics Data System (ADS)

Poveda, Germán; Zuluaga, Manuel D.

2005-11-01

Taylor's hypothesis (TH) for rainfall fields states that the spatial correlation of rainfall intensity at two points at the same instant of time can be equated with the temporal correlation at two instants of time at some fixed location. The validity of TH is tested in a set of 12 storms developed in Rondonia, southwestern Amazonia, Brazil, during the January-February 1999 Wet Season Atmospheric Meso-scale Campaign. The time Eulerian and Lagrangian Autocorrelation Functions (ACF) are estimated, as well as the time-averaged space ACF, using radar rainfall rates of storms spanning between 3.2 and 23 h, measured at 7-10-min time resolution, over a circle of 100 km radius, at 2 km spatial resolution. TH does not hold in 9 out of the 12 studied storms, due to their erratic trajectories and very low values of zonal wind velocity at 700 hPa, independently from underlying atmospheric stability conditions. TH was shown to hold for 3 storms, up to a cutoff time scale of 10-15 min, which is closely related to observed features of the life cycle of convective cells in the region. Such cutoff time scale in Amazonian storms is much shorter than the 40 min identified in mid-latitude convective storms, due to much higher values of CAPE and smaller values of storm speed in Amazonian storms as compared to mid-latitude ones, which in turn contribute to a faster destruction of the rainfall field isotropy. Storms satisfying TH undergo smooth linear trajectories over space, and exhibit the highest negative values of maximum, mean and minimum zonal wind velocity at 700 hPa, within narrow ranges of atmospheric stability conditions. Non-dimensional parameters involving CAPE (maximum, mean and minimum) and CINE (mean) are identified during the storms life cycle, for which TH holds: CAPE mean/CINE mean = [30-35], CAPE max/CINE mean = [32-40], and CAPE min/CINE mean = [22-28]. These findings are independent upon the timing of storms within the diurnal cycle. Also, the estimated Eulerian time ACF's decay faster than the time-averaged space and the Lagrangian time ACF's, irrespectively of TH validity. The Eulerian ACF's exhibit shorter e-folding times, reflecting smaller correlations over short time scales, but also shorter scale of fluctuation, reflecting less persistence in time than over space. No significant associations (linear, exponential or power law) were found between estimated e-folding times and scale of fluctuation, with all estimates of CAPE and CINE. Secondary correlation maxima appear between 50 and 70 min in the Lagrangian time ACF's for storms satisfying TH. No differences were found in the behavior of each of the three ACF's for storms developed during either the Easterly or Westerly zonal wind regimes which characterize the development of meso-scale convective systems over the region. These results have important implications for modelling and downscaling rainfall fields over tropical land areas.

A web-based Tamsui River flood early-warning system with correction of real-time water stage using monitoring data

NASA Astrophysics Data System (ADS)

Liao, H. Y.; Lin, Y. J.; Chang, H. K.; Shang, R. K.; Kuo, H. C.; Lai, J. S.; Tan, Y. C.

2017-12-01

Taiwan encounters heavy rainfalls frequently. There are three to four typhoons striking Taiwan every year. To provide lead time for reducing flood damage, this study attempt to build a flood early-warning system (FEWS) in Tanshui River using time series correction techniques. The predicted rainfall is used as the input for the rainfall-runoff model. Then, the discharges calculated by the rainfall-runoff model is converted to the 1-D river routing model. The 1-D river routing model will output the simulating water stages in 487 cross sections for the future 48-hr. The downstream water stage at the estuary in 1-D river routing model is provided by storm surge simulation. Next, the water stages of 487 cross sections are corrected by time series model such as autoregressive (AR) model using real-time water stage measurements to improve the predicted accuracy. The results of simulated water stages are displayed on a web-based platform. In addition, the models can be performed remotely by any users with web browsers through a user interface. The on-line video surveillance images, real-time monitoring water stages, and rainfalls can also be shown on this platform. If the simulated water stage exceeds the embankments of Tanshui River, the alerting lights of FEWS will be flashing on the screen. This platform runs periodically and automatically to generate the simulation graphic data of flood water stages for flood disaster prevention and decision making.

Global differences between moderate and large storms

NASA Astrophysics Data System (ADS)

Valek, P. W.; Buzulukova, N.; Fok, M. C. H.; Goldstein, J.; Keesee, A. M.; McComas, D. J.; Perez, J. D.

2015-12-01

The current solar maximum has been relatively quiet compared to previous solar cycles. Whereas numerous moderate storms (Dst < -50 nT) have occurred, there have been only a small number of large (Dst < - 100 nT) and extreme (Dst < -200 nT) storms. Throughout this sequence of storms, the Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission has since 2008 observed the inner magnetosphere. TWINS consists of two ENA cameras flown aboard two separate spacecraft in Molniya orbits. TWINS images the ENA emissions from the inner magnetosphere across a broad range of energies (1 to 100 keV for H, 16 to 256 keV for O). This allows TWINS to observe the evolution in space and time of the trapped and precipitating particles most relevant for storm time dynamics on very high time scales (i.e., minutes). Here we will present the differences seen between moderate storms and the two large storms of 17 March 2015 (Dst < -223, St. Patrick's day storm) and 22 June 2015 (Dst < -195 nT). We will present composition-separated ENA observations of the inner magnetosphere covering the both the medium (1 to 30 keV) and high (30 to > 100 keV) energy ranges, and describe how the inner magnetosphere evolves during storm time.

Statistical Determination of Rainfall-Runoff Erosivity Indices for Single Storms in the Chinese Loess Plateau

PubMed Central

Zheng, Mingguo; Chen, Xiaoan

2015-01-01

Correlation analysis is popular in erosion- or earth-related studies, however, few studies compare correlations on a basis of statistical testing, which should be conducted to determine the statistical significance of the observed sample difference. This study aims to statistically determine the erosivity index of single storms, which requires comparison of a large number of dependent correlations between rainfall-runoff factors and soil loss, in the Chinese Loess Plateau. Data observed at four gauging stations and five runoff experimental plots were presented. Based on the Meng’s tests, which is widely used for comparing correlations between a dependent variable and a set of independent variables, two methods were proposed. The first method removes factors that are poorly correlated with soil loss from consideration in a stepwise way, while the second method performs pairwise comparisons that are adjusted using the Bonferroni correction. Among 12 rainfall factors, I 30 (the maximum 30-minute rainfall intensity) has been suggested for use as the rainfall erosivity index, although I 30 is equally correlated with soil loss as factors of I 20, EI 10 (the product of the rainfall kinetic energy, E, and I 10), EI 20 and EI 30 are. Runoff depth (total runoff volume normalized to drainage area) is more correlated with soil loss than all other examined rainfall-runoff factors, including I 30, peak discharge and many combined factors. Moreover, sediment concentrations of major sediment-producing events are independent of all examined rainfall-runoff factors. As a result, introducing additional factors adds little to the prediction accuracy of the single factor of runoff depth. Hence, runoff depth should be the best erosivity index at scales from plots to watersheds. Our findings can facilitate predictions of soil erosion in the Loess Plateau. Our methods provide a valuable tool while determining the predictor among a number of variables in terms of correlations. PMID:25781173

Statistical determination of rainfall-runoff erosivity indices for single storms in the Chinese Loess Plateau.

PubMed

Zheng, Mingguo; Chen, Xiaoan

2015-01-01

Correlation analysis is popular in erosion- or earth-related studies, however, few studies compare correlations on a basis of statistical testing, which should be conducted to determine the statistical significance of the observed sample difference. This study aims to statistically determine the erosivity index of single storms, which requires comparison of a large number of dependent correlations between rainfall-runoff factors and soil loss, in the Chinese Loess Plateau. Data observed at four gauging stations and five runoff experimental plots were presented. Based on the Meng's tests, which is widely used for comparing correlations between a dependent variable and a set of independent variables, two methods were proposed. The first method removes factors that are poorly correlated with soil loss from consideration in a stepwise way, while the second method performs pairwise comparisons that are adjusted using the Bonferroni correction. Among 12 rainfall factors, I30 (the maximum 30-minute rainfall intensity) has been suggested for use as the rainfall erosivity index, although I30 is equally correlated with soil loss as factors of I20, EI10 (the product of the rainfall kinetic energy, E, and I10), EI20 and EI30 are. Runoff depth (total runoff volume normalized to drainage area) is more correlated with soil loss than all other examined rainfall-runoff factors, including I30, peak discharge and many combined factors. Moreover, sediment concentrations of major sediment-producing events are independent of all examined rainfall-runoff factors. As a result, introducing additional factors adds little to the prediction accuracy of the single factor of runoff depth. Hence, runoff depth should be the best erosivity index at scales from plots to watersheds. Our findings can facilitate predictions of soil erosion in the Loess Plateau. Our methods provide a valuable tool while determining the predictor among a number of variables in terms of correlations.

Animal model of respiratory syncytial virus: CD8+ T cells cause a cytokine storm that is chemically tractable by sphingosine-1-phosphate 1 receptor agonist therapy.

PubMed

Walsh, Kevin B; Teijaro, John R; Brock, Linda G; Fremgen, Daniel M; Collins, Peter L; Rosen, Hugh; Oldstone, Michael B A

2014-06-01

The cytokine storm is an intensified, dysregulated, tissue-injurious inflammatory response driven by cytokine and immune cell components. The cytokine storm during influenza virus infection, whereby the amplified innate immune response is primarily responsible for pulmonary damage, has been well characterized. Now we describe a novel event where virus-specific T cells induce a cytokine storm. The paramyxovirus pneumonia virus of mice (PVM) is a model of human respiratory syncytial virus (hRSV). Unexpectedly, when C57BL/6 mice were infected with PVM, the innate inflammatory response was undetectable until day 5 postinfection, at which time CD8(+) T cells infiltrated into the lung, initiating a cytokine storm by their production of gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). Administration of an immunomodulatory sphingosine-1-phosphate (S1P) receptor 1 (S1P1R) agonist significantly inhibited PVM-elicited cytokine storm by blunting the PVM-specific CD8(+) T cell response, resulting in diminished pulmonary disease and enhanced survival. A dysregulated overly exuberant immune response, termed a "cytokine storm," accompanies virus-induced acute respiratory diseases (VARV), is primarily responsible for the accompanying high morbidity and mortality, and can be controlled therapeutically in influenza virus infection of mice and ferrets by administration of sphingosine-1-phosphate 1 receptor (S1P1R) agonists. Here, two novel findings are recorded. First, in contrast to influenza infection, where the cytokine storm is initiated early by the innate immune system, for pneumonia virus of mice (PVM), a model of RSV, the cytokine storm is initiated late in infection by the adaptive immune response: specifically, by virus-specific CD8 T cells via their release of IFN-γ and TNF-α. Blockading these cytokines with neutralizing antibodies blunts the cytokine storm and protects the host. Second, PVM infection is controlled by administration of an S1P1R agonist.

Automatic Near-Real-Time Image Processing Chain for Very High Resolution Optical Satellite Data

NASA Astrophysics Data System (ADS)

Ostir, K.; Cotar, K.; Marsetic, A.; Pehani, P.; Perse, M.; Zaksek, K.; Zaletelj, J.; Rodic, T.

2015-04-01

In response to the increasing need for automatic and fast satellite image processing SPACE-SI has developed and implemented a fully automatic image processing chain STORM that performs all processing steps from sensor-corrected optical images (level 1) to web-delivered map-ready images and products without operator's intervention. Initial development was tailored to high resolution RapidEye images, and all crucial and most challenging parts of the planned full processing chain were developed: module for automatic image orthorectification based on a physical sensor model and supported by the algorithm for automatic detection of ground control points (GCPs); atmospheric correction module, topographic corrections module that combines physical approach with Minnaert method and utilizing anisotropic illumination model; and modules for high level products generation. Various parts of the chain were implemented also for WorldView-2, THEOS, Pleiades, SPOT 6, Landsat 5-8, and PROBA-V. Support of full-frame sensor currently in development by SPACE-SI is in plan. The proposed paper focuses on the adaptation of the STORM processing chain to very high resolution multispectral images. The development concentrated on the sub-module for automatic detection of GCPs. The initially implemented two-step algorithm that worked only with rasterized vector roads and delivered GCPs with sub-pixel accuracy for the RapidEye images, was improved with the introduction of a third step: super-fine positioning of each GCP based on a reference raster chip. The added step exploits the high spatial resolution of the reference raster to improve the final matching results and to achieve pixel accuracy also on very high resolution optical satellite data.

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

Anderson, B. R.; Millan, R. M.; Reeves, G. D.

We report that past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms (Dst >₋50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result inmore » flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.« less

Storm phase-partitioned rates and budgets of global Alfvénic energy deposition, electron precipitation, and ion outflow

NASA Astrophysics Data System (ADS)

Hatch, Spencer M.; LaBelle, James; Chaston, Christopher C.

2018-01-01

We review the role of Alfvén waves in magnetosphere-ionosphere coupling during geomagnetically active periods, and use three years of high-latitude FAST satellite observations of inertial Alfvén waves (IAWs) together with 55 years of tabulated measurements of the Dst index to answer the following questions: 1) How do global rates of IAW-related energy deposition, electron precipitation, and ion outflow during storm main phase and storm recovery phase compare with global rates during geomagnetically quiet periods? 2) What fraction of net IAW-related energy deposition, electron precipitation, and ion outflow is associated with storm main phase and storm recovery phase; that is, how are these budgets partitioned by storm phase? We find that during the period between October 1996 and November 1999, rates of IAW-related energy deposition, electron precipitation, and ion outflow during geomagnetically quiet periods are increased by factors of 4-5 during storm phases. We also find that ∼62-68% of the net Alfvénic energy deposition, electron precipitation, and ion outflow in the auroral ionosphere occurred during storm main and recovery phases, despite storm phases comprising only 31% of this period. In particular storm main phase, which comprised less than 14% of the three-year period, was associated with roughly a third of the total Alfvénic energy input and ion outflow in the auroral ionosphere. Measures of geomagnetic activity during the IAW study period fall near corresponding 55-year median values, from which we conclude that each storm phase is associated with a fraction of total Alfvénic energy, precipitation, and outflow budgets in the auroral ionosphere that is, in the long term, probably as great or greater than the fraction associated with geomagnetic quiescence for all times except possibly those when geomagnetic activity is protractedly weak, such as solar minimum. These results suggest that the budgets of IAW-related energy deposition, electron precipitation, and ion outflow are roughly equally partitioned by geomagnetic storm phase.

Measuring Bathymetry, Runup, and Beach Volume Change during Storms: New Methodology Quantifies Substantial Changes in Cross-Shore Sediment Flux

NASA Astrophysics Data System (ADS)

Brodie, K. L.; McNinch, J. E.

2009-12-01

Accurate predictions of beach change during storms are contingent upon a correct understanding of wave-driven sediment exchange between the beach and nearshore during high energy conditions. Conventional storm data sets use “pre” (often weeks to months prior) and “post” (often many days after the storm in calm conditions) collections of beach topography and nearshore bathymetry to characterize the effects of the storm. These data have led to a common theory for wave-driven event response of the nearshore system, wherein bars and shorelines are smoothed and straightened by strong alongshore currents into two-dimensional, linear forms. Post-storm, the shoreline accretes, bars migrate onshore, and three-dimensional shapes begin to build as low-energy swell returns. Unfortunately, these approaches have left us with a knowledge gap of the extent and timing of erosion and accretion during storms, arguably the most important information both for scientists trying to model storm damage or inundation, and homeowners trying to manage their properties. This work presents the first spatially extensive (10 km alongshore) and temporally high-resolution (dt = 12 hours) quantitative data set of beach volume and nearshore bathymetry evolution during a Nor’easter on North Carolina’s Outer Banks. During the Nor’easter, significant wave height peaked at 3.4 m, and was greater than 2 m for 37 hours, as measured by the Duck FRF 8 m array. Data were collected using CLARIS: Coastal Lidar and Radar Imaging System, a mobile system that couples simultaneous observations of beach topography from a Riegl laser scanner and nearshore bathymetry (out to ~1 km offshore) from X-Band radar-derived celerity measurements (BASIR). The merging of foreshore lidar elevations with 6-min averages of radar-derived swash runup also enables mapping of maximum-runup elevations alongshore during the surveys. Results show that during the storm, neither the shoreline nor nearshore bathymetry returned to a linear system, as shoreline megacusps/embayments and nearshore shore-oblique bars/troughs both persisted and remained aligned throughout the storm. Analysis of beach volume change above the MHW line showed that all of the erosion occurred during the first 24 hours of the storm, as the 8-m significant wave height grew from 1 to 3.5 m at the peak of the storm and wave period increased from 6 to 14 s. In the 12 hours immediately following the storm peak, as long-period swell fell only 1 m, at least 50% of the eroded upper-beach volume returned along the entire study site, with 100% and greater returning along half the study site. This erosion and accretion would be completely unobserved using traditional pre- and post-storm data sets. Maximum runup varied by as much as 2 m alongshore, showing a weak positive correlation with foreshore slope. Maximum runup is the sum of regional tide and surge (pressure and wind-driven) water levels as well as localized wave-driven setup and swash, and thus may have complex alongshore variations where irregular nearshore bathymetry significantly influences shoreline wave-setup.

Characterizations of the first flush in storm water runoff from an urban roadway.

PubMed

Lee, B C; Matsui, S; Shimizu, Y; Matsuda, T

2005-07-01

Storm water runoff from urban roadways contains anthropogenic pollutants, which are mainly generated from traffic-related activities. The purpose of this study was to evaluate the characteristics of pollutants from the roadway runoff as well as first flush effects. Storm water runoff was sampled during five storm events from the experimental site in Otsu, Shiga, Japan. From the hydrographs and pollutographs for the roadway runoff, the concentration of pollutants increased with increasing runoff flow in the low flow rate event, but did not significantly increase in the high flow rate event. Moreover, according to the analysis of cumulative pollutant mass versus runoff volume curves from five storm events, the first 50% of the runoff volume transported 62% of TOC and Mo, 60% of SS, 59% of Fe, Mn and Cu, 58% of Ni, 57% of Cd and Pb, 56% of Al, 55% of Zn, and 54% of Cr, as the mean values. The first 30% and 80% of the runoff volume also transported 34-43% mass of the pollutants and 82-88% mass of the pollutants, respectively. This study for storm water runoff may also provide useful information to correctly design treatment facilities, such as detention tanks and ponds, filtration and adsorption systems.

Acceleration and loss of relativistic electrons during small geomagnetic storms

DOE PAGES

Anderson, B. R.; Millan, R. M.; Reeves, G. D.; ...

2015-12-02

We report that past studies of radiation belt relativistic electrons have favored active storm time periods, while the effects of small geomagnetic storms (Dst >₋50 nT) have not been statistically characterized. In this timely study, given the current weak solar cycle, we identify 342 small storms from 1989 through 2000 and quantify the corresponding change in relativistic electron flux at geosynchronous orbit. Surprisingly, small storms can be equally as effective as large storms at enhancing and depleting fluxes. Slight differences exist, as small storms are 10% less likely to result in flux enhancement and 10% more likely to result inmore » flux depletion than large storms. Nevertheless, it is clear that neither acceleration nor loss mechanisms scale with storm drivers as would be expected. Small geomagnetic storms play a significant role in radiation belt relativistic electron dynamics and provide opportunities to gain new insights into the complex balance of acceleration and loss processes.« less

Validation of Real-time Modeling of Coronal Mass Ejections Using the WSA-ENLIL+Cone Heliospheric Model

NASA Astrophysics Data System (ADS)

Romano, M.; Mays, M. L.; Taktakishvili, A.; MacNeice, P. J.; Zheng, Y.; Pulkkinen, A. A.; Kuznetsova, M. M.; Odstrcil, D.

2013-12-01

Modeling coronal mass ejections (CMEs) is of great interest to the space weather research and forecasting communities. We present recent validation work of real-time CME arrival time predictions at different satellites using the WSA-ENLIL+Cone three-dimensional MHD heliospheric model available at the Community Coordinated Modeling Center (CCMC) and performed by the Space Weather Research Center (SWRC). SWRC is an in-house research-based operations team at the CCMC which provides interplanetary space weather forecasting for NASA's robotic missions and performs real-time model validation. The quality of model operation is evaluated by comparing its output to a measurable parameter of interest such as the CME arrival time and geomagnetic storm strength. The Kp index is calculated from the relation given in Newell et al. (2007), using solar wind parameters predicted by the WSA-ENLIL+Cone model at Earth. The CME arrival time error is defined as the difference between the predicted arrival time and the observed in-situ CME shock arrival time at the ACE, STEREO A, or STEREO B spacecraft. This study includes all real-time WSA-ENLIL+Cone model simulations performed between June 2011-2013 (over 400 runs) at the CCMC/SWRC. We report hit, miss, false alarm, and correct rejection statistics for all three spacecraft. For hits we show the average absolute CME arrival time error, and the dependence of this error on CME input parameters such as speed, width, and direction. We also present the predicted geomagnetic storm strength (using the Kp index) error for Earth-directed CMEs.

Probabilistic Forecasting of Coastal Morphodynamic Storm Response at Fire Island, New York

NASA Astrophysics Data System (ADS)

Wilson, K.; Adams, P. N.; Hapke, C. J.; Lentz, E. E.; Brenner, O.

2013-12-01

Site-specific probabilistic models of shoreline change are useful because they are derived from direct observations so that local factors, which greatly influence coastal response, are inherently considered by the model. Fire Island, a 50-km barrier island off Long Island, New York, is periodically subject to large storms, whose waves and storm surge dramatically alter beach morphology. Nor'Ida, which impacted the Fire Island coast in 2009, was one of the larger storms to occur in the early 2000s. In this study, we improve upon a Bayesian Network (BN) model informed with historical data to predict shoreline change from Nor'Ida. We present two BN models, referred to as 'original' model (BNo) and 'revised' model (BNr), designed to predict the most probable magnitude of net shoreline movement (NSM), as measured at 934 cross-shore transects, spanning 46 km. Both are informed with observational data (wave impact hours, shoreline and dune toe change rates, pre-storm beach width, and measured NSM) organized within five nodes, but the revised model contains a sixth node to represent the distribution of material added during an April 2009 nourishment project. We evaluate model success by examining the percentage of transects on which the model chooses the correct (observed) bin value of NSM. Comparisons of observed to model-predicted NSM show BNr has slightly higher predictive success over the total study area and significantly higher success at nourished locations. The BNo, which neglects anthropogenic modification history, correctly predicted the most probable NSM in 66.6% of transects, with ambiguous prediction at 12.7% of the locations. BNr, which incorporates anthropogenic modification history, resulted in 69.4% predictive accuracy and 13.9% ambiguity. However, across nourished transects, BNr reported 72.9% predictive success, while BNo reported 61.5% success. Further, at nourished transects, BNr reported higher ambiguity of 23.5% compared to 9.9% in BNo. These results demonstrate that BNr recognizes that nourished transects may behave differently from the expectation derived from historical data and therefore is more 'cautious' in its predictions at these locations. In contrast, BNo is more confident, but less accurate, demonstrating the risk of ignoring the influences of anthropogenic modification in a probabilistic model. Over the entire study region, both models produced greatest predictive accuracy for low retreat observations (BNo: 77.6%; BNr: 76.0%) and least success at predicting low advance observations, although BNr shows considerable improvement over BNo (39.4% vs. 28.6%, respectively). BNr also was significantly more accurate at predicting observations of no shoreline change (BNo: 56.2%; BNr: 68.93%). Both models were accurate for 60% of high advance observations, and reported high predictive success for high retreat observations (BNo: 69.1%; BNr: 67.6%), the scenario of greatest concern to coastal managers.

New dust opacity mapping from Viking Infrared Thermal Mapper data

NASA Technical Reports Server (NTRS)

Martin, Terry Z.; Richardson, Mark I.

1993-01-01

Global dust opacity mapping for Mars has been carried forward using the approach described by Martin (1986) for Viking IR Thermal Mapper data. New maps are presented for the period from the beginning of Viking observations, until Ls 210 deg in 1979 (1.36 Mars years). This range includes the second and more extensive planet-encircling dust storm observed by Viking, known as storm 1977b. Improvements in approach result in greater time resolution and smaller noise than in the earlier work. A strong local storm event filled the Hellas basin at Ls 170 deg, prior to the 1977a storm. Dust is retained in equatorial regions following the 1977b storm far longer than in mid-latitudes. Minor dust events appear to raise the opacity in northern high latitudes during northern spring. Additional mapping with high time resolution has been done for the periods of time near the major storm origins in order to search for clues to the mechanism of storm initiation. The first evidence of the start of the 1977b storm is pushed back to Ls 274.2 deg, preceding signs of the storm in images by about 15 hours.

Observations of the structure and evolution of surface and flight-level wind asymmetries in Hurricane Rita (2005)

NASA Astrophysics Data System (ADS)

Rogers, Robert; Uhlhorn, Eric

2008-11-01

Knowledge of the magnitude and distribution of surface winds, including the structure of azimuthal asymmetries in the wind field, are important factors for tropical cyclone forecasting. With its ability to remotely measure surface wind speeds, the stepped frequency microwave radiometer (SFMR) has assumed a prominent role for the operational tropical cyclone forecasting community. An example of this instrument's utility is presented here, where concurrent measurements of aircraft flight-level and SFMR surface winds are used to document the wind field evolution over three days in Hurricane Rita (2005). The amplitude and azimuthal location (phase) of the wavenumber-1 asymmetry in the storm-relative winds varied at both levels over time. The peak was found to the right of storm track at both levels on the first day. By the third day, the peak in flight-level storm-relative winds remained to the right of storm track, but it shifted to left of storm track at the surface, resulting in a 60-degree shift between the surface and flight-level and azimuthal variations in the ratio of surface to flight-level winds. The asymmetric differences between the surface and flight-level maximum wind radii also varied, indicating a vortex whose tilt was increasing.

Chemistry of throughfall under douglas fir and Rocky Mountain juniper. [Pseudotsuga menziesii var. glauca; Juniperus scopulorum

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

Hart, G.E.; Parent, D.R.

1974-01-01

Concentrations of sodium, calcium, magnesium, potassium, phosphorus and nitrate were measured in throughfall under isolated douglas fir (Pseudotsuga menziesii var. glauca) and Rocky Mountain juniper (Juniperus scopulorum) trees in northern Utah for 39 storms in 1970 and 1971. Concentrations were 3-16 times greater under the trees than in the open. Throughfall under douglas fir invariably had higher concentrations than that under juniper. Since most of the chemical input occurs as dry fallout between storms, surface area and form of the canopy are believed to be the prime factors influencing throughfall chemistry in this region. 15 references, 2 figures, 5 tables.

Latitudinal Dependence of the Energy Input into the Mesosphere by High Energy Electrons

NASA Technical Reports Server (NTRS)

Wagner, C. U.; Nikutowski, B.; Ranta, H.

1984-01-01

Night-time ionspheric absorption measurements give the possibility to study the precipitation of high energy electrons into the mesosphere during and after magnetospheric storms. The uniform Finnish riometer network was used together with measurements from Kuhlungsborn and Collm (GDR) to investigate the night-time absorption as a function of latitude (L=6.5 to 2.5) and storm-time for seven storms. The common trends visible in all these events are summarized in a schematic average picture, showing the distribution of increased ionospheric absorption as a function of latitude (L value) and storm-time.

Predicting typhoon-induced storm surge tide with a two-dimensional hydrodynamic model and artificial neural network model

NASA Astrophysics Data System (ADS)

Chen, W.-B.; Liu, W.-C.; Hsu, M.-H.

2012-12-01

Precise predictions of storm surges during typhoon events have the necessity for disaster prevention in coastal seas. This paper explores an artificial neural network (ANN) model, including the back propagation neural network (BPNN) and adaptive neuro-fuzzy inference system (ANFIS) algorithms used to correct poor calculations with a two-dimensional hydrodynamic model in predicting storm surge height during typhoon events. The two-dimensional model has a fine horizontal resolution and considers the interaction between storm surges and astronomical tides, which can be applied for describing the complicated physical properties of storm surges along the east coast of Taiwan. The model is driven by the tidal elevation at the open boundaries using a global ocean tidal model and is forced by the meteorological conditions using a cyclone model. The simulated results of the hydrodynamic model indicate that this model fails to predict storm surge height during the model calibration and verification phases as typhoons approached the east coast of Taiwan. The BPNN model can reproduce the astronomical tide level but fails to modify the prediction of the storm surge tide level. The ANFIS model satisfactorily predicts both the astronomical tide level and the storm surge height during the training and verification phases and exhibits the lowest values of mean absolute error and root-mean-square error compared to the simulated results at the different stations using the hydrodynamic model and the BPNN model. Comparison results showed that the ANFIS techniques could be successfully applied in predicting water levels along the east coastal of Taiwan during typhoon events.

Developing Subdomain Allocation Algorithms Based on Spatial and Communicational Constraints to Accelerate Dust Storm Simulation

PubMed Central

Gui, Zhipeng; Yu, Manzhu; Yang, Chaowei; Jiang, Yunfeng; Chen, Songqing; Xia, Jizhe; Huang, Qunying; Liu, Kai; Li, Zhenlong; Hassan, Mohammed Anowarul; Jin, Baoxuan

2016-01-01

Dust storm has serious disastrous impacts on environment, human health, and assets. The developments and applications of dust storm models have contributed significantly to better understand and predict the distribution, intensity and structure of dust storms. However, dust storm simulation is a data and computing intensive process. To improve the computing performance, high performance computing has been widely adopted by dividing the entire study area into multiple subdomains and allocating each subdomain on different computing nodes in a parallel fashion. Inappropriate allocation may introduce imbalanced task loads and unnecessary communications among computing nodes. Therefore, allocation is a key factor that may impact the efficiency of parallel process. An allocation algorithm is expected to consider the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire simulation. This research introduces three algorithms to optimize the allocation by considering the spatial and communicational constraints: 1) an Integer Linear Programming (ILP) based algorithm from combinational optimization perspective; 2) a K-Means and Kernighan-Lin combined heuristic algorithm (K&K) integrating geometric and coordinate-free methods by merging local and global partitioning; 3) an automatic seeded region growing based geometric and local partitioning algorithm (ASRG). The performance and effectiveness of the three algorithms are compared based on different factors. Further, we adopt the K&K algorithm as the demonstrated algorithm for the experiment of dust model simulation with the non-hydrostatic mesoscale model (NMM-dust) and compared the performance with the MPI default sequential allocation. The results demonstrate that K&K method significantly improves the simulation performance with better subdomain allocation. This method can also be adopted for other relevant atmospheric and numerical modeling. PMID:27044039

The concurrent multiplicative-additive approach for gauge-radar/satellite multisensor precipitation estimates

NASA Astrophysics Data System (ADS)

Garcia-Pintado, J.; Barberá, G. G.; Erena Arrabal, M.; Castillo, V. M.

2010-12-01

Objective analysis schemes (OAS), also called ``succesive correction methods'' or ``observation nudging'', have been proposed for multisensor precipitation estimation combining remote sensing data (meteorological radar or satellite) with data from ground-based raingauge networks. However, opposite to the more complex geostatistical approaches, the OAS techniques for this use are not optimized. On the other hand, geostatistical techniques ideally require, at the least, modelling the covariance from the rain gauge data at every time step evaluated, which commonly cannot be soundly done. Here, we propose a new procedure (concurrent multiplicative-additive objective analysis scheme [CMA-OAS]) for operational rainfall estimation using rain gauges and meteorological radar, which does not require explicit modelling of spatial covariances. On the basis of a concurrent multiplicative-additive (CMA) decomposition of the spatially nonuniform radar bias, within-storm variability of rainfall and fractional coverage of rainfall are taken into account. Thus both spatially nonuniform radar bias, given that rainfall is detected, and bias in radar detection of rainfall are handled. The interpolation procedure of CMA-OAS is built on the OAS, whose purpose is to estimate a filtered spatial field of the variable of interest through a successive correction of residuals resulting from a Gaussian kernel smoother applied on spatial samples. The CMA-OAS, first, poses an optimization problem at each gauge-radar support point to obtain both a local multiplicative-additive radar bias decomposition and a regionalization parameter. Second, local biases and regionalization parameters are integrated into an OAS to estimate the multisensor rainfall at the ground level. The approach considers radar estimates as background a priori information (first guess), so that nudging to observations (gauges) may be relaxed smoothly to the first guess, and the relaxation shape is obtained from the sequential optimization. The procedure is suited to relatively sparse rain gauge networks. To show the procedure, six storms are analyzed at hourly steps over 10,663 km2. Results generally indicated an improved quality with respect to other methods evaluated: a standard mean-field bias adjustment, an OAS spatially variable adjustment with multiplicative factors, ordinary cokriging, and kriging with external drift. In theory, it could be equally applicable to gauge-satellite estimates and other hydrometeorological variables.

Dependence of efficiency of magnetic storm generation on the types of interplanetary drivers.

NASA Astrophysics Data System (ADS)

Yermolaev, Yuri; Nikolaeva, Nadezhda; Lodkina, Irina

2015-04-01

To compare the coupling coefficients between the solar-wind electric field Ey and Dst (and corrected Dst*) index during the magnetic storms generated by different types of interplanetary drivers, we use the Kyoto Dst-index data, the OMNI data of solar wind plasma and magnetic field measurements, and our "Catalog of large scale phenomena during 1976-2000" (published in [1] and presented on websites: ftp://ftp.iki.rssi.ru/pub/omni/). Both indexes at the main phase of magnetic storms are approximated by the linear dependence on the following solar wind parameters: integrated electric field of solar wind (sumEy), solar wind dynamic pressure (Pd), and the level of magnetic field fluctuations (sB), and the fitting coefficients are determined by the technique of least squares. We present the results of the main phase modelling for magnetic storms with Dst<-50 nT induced by 4 types of the solar wind streams: MC (10 events), CIR (41), Sheath (26), Ejecta (45). Our analysis [2, 3] shows that the coefficients of coupling between Dst and Dst* indexes and integral electric field are significantly higher for Sheath (for Dst*and Dst they are -3.4 and -3.3 nT/V m-1 h, respectively) and CIR (-3.0 and -2.8) than for MC (-2.0 and -2.5) and Ejecta (-2.1 and -2.3). Thus we obtained additional confirmation of experimental fact that Sheath and CIR have higher efficiency in generation of magnetic storms than MC and Ejecta. This work was supported by the RFBR, project 13-02-00158a, and by the Program 9 of Presidium of Russian Academy of Sciences. References 1. Yu. I. Yermolaev, N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev, Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, 2009, Vol. 47, No. 2, pp. 81-94. 2. N.S. Nikolaeva, Yu.I. Yermolaev, I.G. Lodkina, Modeling of Dst-index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Research, 2013, Vol. 51, No. 6, pp. 401-412 3. Nikolaeva N.S., Yermolaev Yu.I., Lodkina I.G., Modeling of corrected Dst-index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Research, 2015, Vol.53, No. 2, 81, DOI: 10.7868/S0023420615020077

Timing Calibration in PET Using a Time Alignment Probe

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

Moses, William W.; Thompson, Christopher J.

2006-05-05

We evaluate the Scanwell Time Alignment Probe for performing the timing calibration for the LBNL Prostate-Specific PET Camera. We calibrate the time delay correction factors for each detector module in the camera using two methods--using the Time Alignment Probe (which measures the time difference between the probe and each detector module) and using the conventional method (which measures the timing difference between all module-module combinations in the camera). These correction factors, which are quantized in 2 ns steps, are compared on a module-by-module basis. The values are in excellent agreement--of the 80 correction factors, 62 agree exactly, 17 differ bymore » 1 step, and 1 differs by 2 steps. We also measure on-time and off-time counting rates when the two sets of calibration factors are loaded into the camera and find that they agree within statistical error. We conclude that the performance using the Time Alignment Probe and conventional methods are equivalent.« less

Acute respiratory failure due to thyroid storm developing immediately after delivery.

PubMed

Kitazawa, Chie; Aoki, Shigeru; Takahashi, Tsuneo; Hirahara, Fumiki

2015-12-01

Acute respiratory failure occurs in less than 0.1% of pregnancies. Thyroid storm should be included in the differential diagnosis of possible causes of acute respiratory failure occurring immediately after delivery, and delivery is a high risk factor for thyroid storm in pregnant women with thyrotoxicosis.

Ionospheric disturbances under low solar activity conditions

NASA Astrophysics Data System (ADS)

Buresova, D.; Lastovicka, J.; Hejda, P.; Bochnicek, J.

2014-07-01

The paper is focused on ionospheric response to occasional magnetic disturbances above selected ionospheric stations located at middle latitudes of the Northern and Southern Hemisphere under extremely low solar activity conditions of 2007-2009. We analyzed changes in the F2 layer critical frequency foF2 and the F2 layer peak height hmF2 against 27-days running mean obtained for different longitudinal sectors of both hemispheres for the initial, main and recovery phases of selected magnetic disturbances. Our analysis showed that the effects on the middle latitude ionosphere of weak-to-moderate CIR-related magnetic storms, which mostly occur around solar minimum period, could be comparable with the effects of strong magnetic storms. In general, both positive and negative deviations of foF2 and hmF2 have been observed independent on season and location. However positive effects on foF2 prevailed and were more significant. Observations of stormy ionosphere also showed large departures from the climatology within storm recovery phase, which are comparable with those usually observed during the storm main phase. The IRI STORM model gave no reliable corrections of foF2 for analyzed events.

Lightning and precipitation history of a microburst-producing storm

NASA Technical Reports Server (NTRS)

Goodman, Steven J.; Buechler, Dennis E.; Wright, Patrick D.; Rust, W. David

1988-01-01

Quantitative measurements of the lightning and precipitation life cycle of a microburst-producing storm are discussed. The storm, which occurred on July 20, 1986 at Huntsville, Alabama, was studied using Doppler radar data. The storm produced 116 flashes, 6 of which were discharges to the ground. It is suggested that an abrupt decrease in the total flash rates is associated with storm collapse, and serves as a precursor to the arrival of the maximum microburst outflows at the surface. Ice-phase precipitation is shown to be an important factor in both the formation of the strong downdraft and the electrification of the storm.

Errors in imaging patients in the emergency setting.

PubMed

Pinto, Antonio; Reginelli, Alfonso; Pinto, Fabio; Lo Re, Giuseppe; Midiri, Federico; Muzj, Carlo; Romano, Luigia; Brunese, Luca

2016-01-01

Emergency and trauma care produces a "perfect storm" for radiological errors: uncooperative patients, inadequate histories, time-critical decisions, concurrent tasks and often junior personnel working after hours in busy emergency departments. The main cause of diagnostic errors in the emergency department is the failure to correctly interpret radiographs, and the majority of diagnoses missed on radiographs are fractures. Missed diagnoses potentially have important consequences for patients, clinicians and radiologists. Radiologists play a pivotal role in the diagnostic assessment of polytrauma patients and of patients with non-traumatic craniothoracoabdominal emergencies, and key elements to reduce errors in the emergency setting are knowledge, experience and the correct application of imaging protocols. This article aims to highlight the definition and classification of errors in radiology, the causes of errors in emergency radiology and the spectrum of diagnostic errors in radiography, ultrasonography and CT in the emergency setting.

The Perfect Storm--Genetic Engineering, Science, and Ethics

ERIC Educational Resources Information Center

Rollin, Bernard E.

2014-01-01

Uncertainty about ethics has been a major factor in societal rejection of biotechnology. Six factors help create a societal "perfect storm" regarding ethics and biotechnology: Social demand for ethical discussion; societal scientific illiteracy; poor social understanding of ethics; a "Gresham's Law for Ethics;" Scientific…

Time Delay Between Dst Index and Magnetic Storm Related Structure in the Solar Wind

NASA Technical Reports Server (NTRS)

Osherovich, Vladimir A.; Fainberg, Joseph

2015-01-01

Benson et al. (2015, this volume) selected 10 large magnetic storms, with associated Dst minimum values less than or equal to -100 nT, for which high-latitude topside ionospheric electron density profiles are available from topside-sounder satellites. For these 10 storms, we performed a superposition of Dst and interplanetary parameters B, v, N(sub p) and T(sub p). We have found that two interplanetary parameters, namely B and v, are sufficient to reproduce Dst with correlation coefficient cc approximately 0.96 provided that the interplanetary parameter times are taken 0.15 days earlier than the associated Dst times. Thus we have found which part of the solar wind is responsible for each phase of the magnetic storm. This result is also verified for individual storms as well. The total duration of SRS (storm related structure in the solar wind) is 4 - 5 days which is the same as the associated Dst interval of the magnetic storm.

Defining Coastal Storm and Quantifying Storms Applying Coastal Storm Impulse Parameter

NASA Astrophysics Data System (ADS)

Mahmoudpour, Nader

2014-05-01

What defines a storm condition and what would initiate a "storm" has not been uniquely defined among scientists and engineers. Parameters that have been used to define a storm condition can be mentioned as wind speed, beach erosion and storm hydrodynamics parameters such as wave height and water levels. Some of the parameters are storm consequential such as beach erosion and some are not directly related to the storm hydrodynamics such as wind speed. For the purpose of the presentation, the different storm conditions based on wave height, water levels, wind speed and beach erosion will be discussed and assessed. However, it sounds more scientifically to have the storm definition based on the hydrodynamic parameters such as wave height, water level and storm duration. Once the storm condition is defined and storm has initiated, the severity of the storm would be a question to forecast and evaluate the hazard and analyze the risk in order to determine the appropriate responses. The correlation of storm damages to the meteorological and hydrodynamics parameters can be defined as a storm scale, storm index or storm parameter and it is needed to simplify the complexity of variation involved developing the scale for risk analysis and response management. A newly introduced Coastal Storm Impulse (COSI) parameter quantifies storms into one number for a specific location and storm event. The COSI parameter is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. The COSI parameter applies the principle of conservation of momentum to physically combine the hydrodynamic variables per unit width of shoreline. This total momentum is then integrated over the duration of the storm to determine the storm's impulse to the coast. The COSI parameter employs the mean, time-averaged nonlinear (Fourier) wave momentum flux, over the wave period added to the horizontal storm surge momentum above the Mean High Water (MHW) integrated over the storm duration. The COSI parameter methodology has been applied to a 10-year data set from 1994 to 2003 at US Army Corps of Engineers, Field Research Facility (FRF) located on the Atlantic Ocean in Duck, North Carolina. The storm duration was taken as the length of time (hours) that the spectral significant wave heights were equal or greater than 1.6 meters for at least a 12 hour, continuous period. Wave heights were measured in 8 meters water depth and water levels measured at the NOAA/NOS tide gauge at the end of the FRF pier. The 10-year data set were analyzed applying the aforementioned storm criteria and produced 148 coastal events including Hurricanes and Northeasters. The results of this analysis and application of the COSI parameter to determine "Extra Ordinary" storms in Federal Projects for the Gulf of Mexico, 2012 hurricane season will be discussed at the time of presentation.

Storms drive altitudinal migration in a tropical bird

PubMed Central

Boyle, W. Alice; Norris, D. Ryan; Guglielmo, Christopher G.

2010-01-01

Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals. PMID:20375047

Storms drive altitudinal migration in a tropical bird.

PubMed

Boyle, W Alice; Norris, D Ryan; Guglielmo, Christopher G

2010-08-22

Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms to mortality risks via reductions in foraging time and provide, to our knowledge, the first tests of this hypothesis in the White-ruffed Manakin (Corapipo altera), a small partially migratory frugivore breeding on the Atlantic slope of Costa Rica. As predicted, variation in rainfall was associated with plasma corticosterone levels, fat stores, plasma metabolites and haematocrit. By collecting data at high and low elevation sites simultaneously, we also found that high-elevation residents were more adversely affected by storms than low elevation migrants. These results, together with striking temporal capture patterns of altitudinal migrants relative to storms, provide, to our knowledge, the first evidence that weather-related risks incurred by species requiring high food intake rates can explain altitudinal migrations of tropical animals. These findings resolve conflicting evidence for and against food limitation being important in the evolution of this behaviour, and highlight how endogenous and exogenous processes influence life-history trade-offs made by individuals in the wild. Because seasonal storms are a defining characteristic of most tropical ecosystems and rainfall patterns will probably change in ensuing decades, these results have important implications for understanding the ecology, evolution and conservation of tropical animals.

Extreme EEJ and Topside Ionospheric Response to the 22-23 June 2015 Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Astafyeva, E.; Zakharenkova, I.; Alken, P.; Coisson, P.

2016-12-01

In this work, we study the ionospheric and thermospheric response to the intense geomagnetic storm of 22-23 June 2015. With the minimum SYM-H excursion of -207 nT, this storm is so far the 2nd strongest geomagnetic storm in the current 24th solar cycle. The storm started with the arrival of a coronal mass ejection at 18:37UT on 22 June 2015. The interplanetary magnetic field (IMF) Bz component changed polarity several times during this storm. Consequently, the interplanetary electric field Ey component repeated this oscillatory behavior, and varied from -15 to +20 mV/m, which is comparable with storm-time levels. Data from multiple ground-based and space-borne instruments showed that both positive and negative ionospheric storms occurred during this storm at middle and low latitudes on both day and night sides. To study the drivers of the observed ionospheric effects, we further analyze variations of thermospheric parameters (neutral mass density and thermospheric O/N2 ratio), as well as the equatorial electrojet (EEJ) data as retrieved from magnetic measurements onboard Swarm satellites. One of the most interesting features of the June 2015 storm is observation of extremely high EEJ values (both eastward and westward), that correlate with variations of the IEF Ey. We find that the storm-time penetration electric fields were, most likely, the main driver of the observed ionospheric effects at the initial phase of the storm, and at the beginning of the main phase. At the end of the main phase, the thermospheric composition changes seemed to contribute as well.

Modeling of electron time variations in the radiation belts

NASA Technical Reports Server (NTRS)

Chan, K. W.; Teague, M. J.; Schofield, N. J.; Vette, J. I.

1979-01-01

A review of the temporal variation in the trapped electron population of the inner and outer radiation zones is presented. Techniques presently used for modeling these zones are discussed and their deficiencies identified. An intermediate region is indicated between the zones in which the present modeling techniques are inadequate due to the magnitude and frequency of magnetic storms. Future trends are examined, and it is suggested that modeling of individual magnetic storms may be required in certain L bands. An analysis of seven magnetic storms is presented, establishing the independence of the depletion time of the storm flux and the storm magnitude. Provisional correlation between the storm magnitude and the Dst index is demonstrated.

The Role of Storm Time Electrodynamics in Suppressing the Equatorial Plasma Bubble Development in the Recovery Phase of a Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Sripathi, S.; Banola, S.; Emperumal, K.; Suneel Kumar, B.; Radicella, Sandro M.

2018-03-01

We investigate the role of storm time electrodynamics in suppressing the equatorial plasma bubble (EPB) development using multi-instruments over India during a moderate geomagnetic storm that occurred on 2 October 2013 where Dst minimum reached -80 nT. This storm produced unique signatures in the equatorial ionosphere such that equatorial electrojet strength showed signatures of an abrupt increase of its strength to 150 nT and occurrence of episodes of counter electrojet events. During the main phase of the storm, the interplanetary magnetic field Bz is well correlated with the variations in the equatorial electrojet/counter electrojet suggesting the role of undershielding/overshielding electric fields of magnetospheric origin. Further, observations showed the presence of strong F3 layers at multiple times at multiple stations due to undershielding electric field. Interestingly, we observed simultaneous presence of F3 layers and suppression of EPBs in the dusk sector during the recovery phase. While strong EPBs were observed before and after the day of the geomagnetic storm, suppression of the EPBs on the storm day during "spread F season" is intriguing. Our further analysis using low-latitude station, Hyderabad, during the time of prereversal enhancement suggests that intense Esb layers were observed on the storm day but were absent/weak on quiet days. Based on these results, we suggest that the altitude/latitude variation of disturbance dynamo electric fields/disturbance winds may be responsible for simultaneous detection of F3 layers, occurrence of low-latitude Es layers, and suppression of EPBs during the storm day along the sunset terminator.

Effects of sea level rise, land subsidence, bathymetric change and typhoon tracks on storm flooding in the coastal areas of Shanghai.

PubMed

Wang, Jun; Yi, Si; Li, Mengya; Wang, Lei; Song, Chengcheng

2018-04-15

We compared the effects of three key environmental factors of coastal flooding: sea level rise (SLR), land subsidence (LS) and bathymetric change (BC) in the coastal areas of Shanghai. We use the hydrological simulation model MIKE 21 to simulate flood magnitudes under multiple scenarios created from combinations of the key environmental factors projected to year 2030 and 2050. Historical typhoons (TC9711, TC8114, TC0012, TC0205 and TC1109), which caused extremely high surges and considerable losses, were selected as reference tracks to generate potential typhoon events that would make landfalls in Shanghai (SHLD), in the north of Zhejiang (ZNLD) and moving northwards in the offshore area of Shanghai (MNS) under those scenarios. The model results provided assessment of impact of single and compound effects of the three factors (SLR, LS and BC) on coastal flooding in Shanghai for the next few decades. Model simulation showed that by the year 2030, the magnitude of storm flooding will increase due to the environmental changes defined by SLR, LS, and BC. Particularly, the compound scenario of the three factors will generate coastal floods that are 3.1, 2.7, and 1.9 times greater than the single factor change scenarios by, respectively, SLR, LS, and BC. Even more drastically, in 2050, the compound impact of the three factors would be 8.5, 7.5, and 23.4 times of the single factors. It indicates that the impact of environmental changes is not simple addition of the effects from individual factors, but rather multiple times greater of that when the projection time is longer. We also found for short-term scenarios, the bathymetry change is the most important factor for the changes in coastal flooding; and for long-term scenarios, sea level rise and land subsidence are the major factors that coastal flood prevention and management should address. Copyright © 2017 Elsevier B.V. All rights reserved.

Self-Consistent Model of Magnetospheric Ring Current and Electromagnetic Ion Cyclotron Waves: The May 2-7, 1998, Storm

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Gamayunov, K. V.; Jordanova, V. K.

2003-01-01

Complete description of a self-consistent model for magnetospheric ring current interacting with electromagnetic ion cyclotron waves is presented. The model is based on the system of two kinetic equations; one equation describes the ring current ion dynamics, and another equation describes the wave evolution. The effects on ring current ions interacting with electromagnetic ion cyclotron waves, and back on waves, are considered self-consistently by solving both equations on a global magnetospheric scale under non steady-state conditions. In the paper by Khazanov et al. [2002] this self-consistent model has only been shortly outlined, and discussions of many the model related details have been omitted. For example, in present study for the first time a new algorithm for numerical finding of the resonant numbers for quasilinear wave-particle interaction is described, or it is demonstrated that in order to describe quasilinear interaction in a multi-ion thermal plasma correctly, both e and He(+) modes of electromagnetic ion cyclotron waves should be employed. The developed model is used to simulate the entire May 2-7, 1998 storm period. Trapped number fluxes of the ring current protons are calculated and presented along with their comparison with the data measured by the 3D hot plasma instrument Polar/HYDRA. Examining of the wave (MLT, L shell) distributions produced during the storm progress reveals an essential intensification of the wave emissions in about two days after main phase of storm. This result is well consistent with the earlier ground-based observations. Also the theoretical shapes and the occurrence rates for power spectral densities of electromagnetic ion cyclotron waves are studied. It is found that in about 2 days after the storm main phase on May 4, mainly non Gaussian shapes of power spectral densities are produced.

Stormtime ring current and radiation belt ion transport: Simulations and interpretations

NASA Technical Reports Server (NTRS)

Lyons, Larry R.; Gorney, David J.; Chen, Margaret W.; Schulz, Michael

1995-01-01

We use a dynamical guiding-center model to investigate the stormtime transport of ring current and radiation-belt ions. We trace the motion of representative ions' guiding centers in response to model substorm-associated impulses in the convection electric field for a range of ion energies. Our simple magnetospheric model allows us to compare our numerical results quantitatively with analytical descriptions of particle transport, (e.g., with the quasilinear theory of radial diffusion). We find that 10-145-keV ions gain access to L approximately 3, where they can form the stormtime ring current, mainly from outside the (trapping) region in which particles execute closed drift paths. Conversely, the transport of higher-energy ions (approximately greater than 145 keV at L approximately 3) turns out to resemble radial diffusion. The quasilinear diffusion coefficient calculated for our model storm does not vary smoothly with particle energy, since our impulses occur at specific (although randomly determined) times. Despite the spectral irregularity, quasilinear theory provides a surprisingly accurate description of the transport process for approximately greater than 145-keV ions, even for the case of an individual storm. For 4 different realizations of our model storm, the geometric mean discrepancies between diffusion coefficients D(sup sim, sub LL) obtained from the simulations and the quasilinear diffusion coefficient D(sup ql, sub LL) amount to factors of 2.3, 2.3, 1.5, and 3.0, respectively. We have found that these discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) can be reduced slightly by invoking drift-resonance broadening to smooth out the sharp minima and maxima in D(sup ql, sub LL). The mean of the remaining discrepancies between D(sup sim, sub LL) and D(sup ql, sub LL) for the 4 different storms then amount to factors of 1.9, 2.1, 1.5, and 2.7, respectively. We find even better agreement when we reduce the impulse amplitudes systematically in a given model storm (e.g., reduction of all the impulse amplitudes by half reduces the discrepancy factor by at least its square root) and also when we average our results over an ensemble of 20 model storms (agreement is within a factor of 1.2 without impulse-amplitude reduction). We use our simulation results also to map phase-space densities f in accordance with Liouville's theorem. We find that the stormtime transport of approximately greater than 145-keV ions produces little change in f-bar the drift-averaged phase-space density on any drift shell of interest. However, the stormtime transport produces a major enhancement from the pre-storm phase-space density at energies approximately 30-145 keV, which are representative of the stormtime ring current.

Contributions of substorm injections to SYM-H depressions in the main phase of storms

NASA Astrophysics Data System (ADS)

He, Zhaohai; Dai, Lei; Wang, Chi; Duan, Suping; Zhang, Lingqian; Chen, Tao; Roth, I.

2016-12-01

Substorm injections bring energetic particles to the inner magnetosphere. But the role of the injected population in building up the storm time ring current is not well understood. By surveying Los Alamos National Laboratory geosynchronous data during 34 storm main phases, we show evidence that at least some substorm injections can contribute to substorm-time scale SYM-H/Dst depressions in the main phase of storms. For event studies, we analyze two typical events in which the main-phase SYM-H index exhibited stepwise depressions that are correlated with particle flux enhancement due to injections and with AL index. A statistical study is performed based on 95 storm time injection events. The flux increases of the injected population (50-400 keV) are found proportional to the sharp SYM-H depressions during the injection interval. By identifying dispersionless and dispersive injection signals, we estimate the azimuthal extent of the substorm injection. Statistical results show that the injection regions of these storm time substorms are characterized with an azimuthal extent larger than 06:00 magnetic local time. These results suggest that at least some substorm injections may mimic the large-scale enhanced convection and contribute to sharp decreases of Dst in the storm main phase.

The Complex Relationship Between Heavy Storms and Floods: Implication on Stormwater Drainage design and Management

NASA Astrophysics Data System (ADS)

Demissie, Y.; Mortuza, M. R.; Moges, E.; Yan, E.; Li, H. Y.

2017-12-01

Due to the lack of historical and future streamflow data for flood frequency analysis at or near most drainage sites, it is a common practice to directly estimate the design flood (maximum discharge or volume of stream for a given return period) based on storm frequency analysis and the resulted Intensity-Duration-Frequency (IDF) curves. Such analysis assumes a direct relationship between storms and floods with, for example, the 10-year rainfall expected to produce the 10-year flood. However, in reality, a storm is just one factor among the many other hydrological and metrological factors that can affect the peak flow and hydrograph. Consequently, a heavy storm does not necessarily always lead to flooding or a flood events with the same frequency. This is evident by the observed difference in the seasonality of heavy storms and floods in most regions. In order to understand site specific causal-effect relationship between heavy storms and floods and improve the flood analysis for stormwater drainage design and management, we have examined the contributions of various factors that affect floods using statistical and information theory methods. Based on the identified dominant causal-effect relationships, hydrologic and probability analyses were conducted to develop the runoff IDF curves taking into consideration the snowmelt and rain-on-snow effect, the difference in the storm and flood seasonality, soil moisture conditions, and catchment potential for flash and riverine flooding. The approach was demonstrated using data from military installations located in different parts of the United States. The accuracy of the flood frequency analysis and the resulted runoff IDF curves were evaluated based on the runoff IDF curves developed from streamflow measurements.

The storm-time equatorial electrojet

NASA Technical Reports Server (NTRS)

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1977-01-01

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed, and the large field depression at the flight time must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

The storm-time equatorial electrojet

NASA Technical Reports Server (NTRS)

Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

1976-01-01

A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed and the large field depression, at the flight time, must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

The SZ-5 Spaceship Orbit Changes During The 2003 "Halloween Storm"

NASA Astrophysics Data System (ADS)

Huang, C.; Liu, D.; Guo, J.

2017-12-01

We analyse the daily major semi-axis variations of SZ-5 (ShenZhou V) spaceship during Oct. 20 to Dec. 30 in 2003, which includes the period of the 2003 "Halloween Storm". The significant orbital decay has been observed in late October due to the great solar flares and the severe geomagnetic storms. According to the equation of the air-drag-force on a spacecraft and the SZ-5 orbital decay information, we derive the thermospheric density relative changes during the 2003 "Halloween Storm" and compare the results with the Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Extended Model (NRLMSISE-00). The analyses show that the thermosperic density (at the altitude of SZ-5, about 350 km) in storm time enchances to approximately three times as much as that in the quiet time but the empirical model may underestimate the thermospheric density changes during this severe storm.

A storm-based CSLE incorporating the modified SCS-CN method for soil loss prediction on the Chinese Loess Plateau

NASA Astrophysics Data System (ADS)

Shi, Wenhai; Huang, Mingbin

2017-04-01

The Chinese Loess Plateau is one of the most erodible areas in the world. In order to reduce soil and water losses, suitable conservation practices need to be designed. For this purpose, there is an increasing demand for an appropriate model that can accurately predict storm-based surface runoff and soil losses on the Loess Plateau. The Chinese Soil Loss Equation (CSLE) has been widely used in this region to assess soil losses from different land use types. However, the CSLE was intended only to predict the mean annual gross soil loss. In this study, a CSLE was proposed that would be storm-based and that introduced a new rainfall-runoff erosivity factor. A dataset was compiled that comprised measurements of soil losses during individual storms from three runoff-erosion plots in each of three different watersheds in the gully region of the Plateau for 3-7 years in three different time periods (1956-1959; 1973-1980; 2010-13). The accuracy of the soil loss predictions made by the new storm-based CSLE was determined using the data for the six plots in two of the watersheds measured during 165 storm-runoff events. The performance of the storm-based CSLE was further compared with the performance of the storm-based Revised Universal Soil Loss Equation (RUSLE) for the same six plots. During the calibration (83 storms) and validation (82 storms) of the storm-based CSLE, the model efficiency, E, was 87.7% and 88.9%, respectively, while the root mean square error (RMSE) was 2.7 and 2.3 t ha-1 indicating a high degree of accuracy. Furthermore, the storm-based CSLE performed better than the storm-based RULSE (E: 75.8% and 70.3%; RMSE: 3.8 and 3.7 t ha-1, for the calibration and validation storms, respectively). The storm-based CSLE was then used to predict the soil losses from the three experimental plots in the third watershed. For these predictions, the model parameter values, previously determined by the calibration based on the data from the initial six plots, were used in the storm-based CSLE. In addition, the surface runoff used by the storm-based CSLE was either obtained from measurements or from the values predicted by the modified Soil Conservation Service Curve Number (SCS-CN) method. When using the measured runoff, the storm-based CSLE had an E of 76.6%, whereas the use of the predicted runoff gave an E of 76.4%. The high E values indicated that the storm-based CSLE incorporating the modified SCS-CN method could accurately predict storm-event-based soil losses resulting from both sheet and rill erosion at the field scale on the Chinese Loess Plateau. This approach could be applicable to other areas of the world once the model parameters have been suitably calibrated.

The Role of Substorms in Storm-time Particle Acceleration

NASA Astrophysics Data System (ADS)

Daglis, Ioannis A.; Kamide, Yohsuke

The terrestrial magnetosphere has the capability to rapidly accelerate charged particles up to very high energies over relatively short times and distances. Acceleration of charged particles is an essential ingredient of both magnetospheric substorms and space storms. In the case of space storms, the ultimate result is a bulk flow of electric charge through the inner magnetosphere, commonly known as the ring current. Syun-Ichi Akasofu and Sydney Chapman, two of the early pioneers in space physics, postulated that the bulk acceleration of particles during storms is rather the additive result of partial acceleration during consecutive substorms. This paradigm has been heavily disputed during recent years. The new case is that substorm acceleration may be sufficient to produce individual high-energy particles that create auroras and possibly harm spacecraft, but it cannot produce the massive acceleration that constitutes a storm. This paper is a critical review of the long-standing issue of the storm-substorm relationship, or—in other words—the capability or necessity of substorms in facilitating or driving the build-up of the storm-time ring current. We mainly address the physical effect itself, i.e. the bulk acceleration of particles, and not the diagnostic of the process, i.e. the Dst index, which is rather often the case. Within the framework of particle acceleration, substorms retain their storm-importance due to the potential of substorm-induced impulsive electric fields in obtaining the massive ion acceleration needed for the storm-time ring current buildup.

A Point Rainfall Generator With Internal Storm Structure

NASA Astrophysics Data System (ADS)

Marien, J. L.; Vandewiele, G. L.

1986-04-01

A point rainfall generator is a probabilistic model for the time series of rainfall as observed in one geographical point. The main purpose of such a model is to generate long synthetic sequences of rainfall for simulation studies. The present generator is a continuous time model based on 13.5 years of 10-min point rainfalls observed in Belgium and digitized with a resolution of 0.1 mm. The present generator attempts to model all features of the rainfall time series which are important for flood studies as accurately as possible. The original aspects of the model are on the one hand the way in which storms are defined and on the other hand the theoretical model for the internal storm characteristics. The storm definition has the advantage that the important characteristics of successive storms are fully independent and very precisely modelled, even on time bases as small as 10 min. The model of the internal storm characteristics has a strong theoretical structure. This fact justifies better the extrapolation of this model to severe storms for which the data are very sparse. This can be important when using the model to simulate severe flood events.

Impact of TRMM and SSM/I Rainfall Assimilation on Global Analysis and QPF

NASA Technical Reports Server (NTRS)

Hou, Arthur; Zhang, Sara; Reale, Oreste

2002-01-01

Evaluation of QPF skills requires quantitatively accurate precipitation analyses. We show that assimilation of surface rain rates derived from the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager and Special Sensor Microwave/Imager (SSM/I) improves quantitative precipitation estimates (QPE) and many aspects of global analyses. Short-range forecasts initialized with analyses with satellite rainfall data generally yield significantly higher QPF threat scores and better storm track predictions. These results were obtained using a variational procedure that minimizes the difference between the observed and model rain rates by correcting the moist physics tendency of the forecast model over a 6h assimilation window. In two case studies of Hurricanes Bonnie and Floyd, synoptic analysis shows that this procedure produces initial conditions with better-defined tropical storm features and stronger precipitation intensity associated with the storm.

Scale-dependent behavior of the foredune: Implications for barrier island response to storms and sea-level rise

NASA Astrophysics Data System (ADS)

Houser, Chris; Wernette, Phil; Weymer, Bradley A.

2018-02-01

The impact of storm surge on a barrier island tends to be considered from a single cross-shore dimension, dependent on the relative elevations of the storm surge and dune crest. However, the foredune is rarely uniform and can exhibit considerable variation in height and width at a range of length scales. In this study, LiDAR data from barrier islands in Texas and Florida are used to explore how shoreline position and dune morphology vary alongshore, and to determine how this variability is altered or reinforced by storms and post-storm recovery. Wavelet analysis reveals that a power law can approximate historical shoreline change across all scales, but that storm-scale shoreline change ( 10 years) and dune height exhibit similar scale-dependent variations at swash and surf zone scales (< 1000 m). The in-phase nature of the relationship between dune height and storm-scale shoreline change indicates that areas of greater storm-scale shoreline retreat are associated with areas of smaller dunes. It is argued that the decoupling of storm-scale and historical shoreline change at swash and surf zone scales is also associated with the alongshore redistribution of sediment and the tendency of shorelines to evolve to a more diffusive (or straight) pattern with time. The wavelet analysis of the data for post-storm dune recovery is also characterized by red noise at the smallest scales characteristic of diffusive systems, suggesting that it is possible that small-scale variations in dune height can be repaired through alongshore recovery and expansion if there is sufficient time between storms. However, the time required for dune recovery exceeds the time between storms capable of eroding and overwashing the dune. Correlation between historical shoreline retreat and the variance of the dune at swash and surf zone scales suggests that the persistence of the dune is an important control on transgression through island migration or shoreline retreat with relative sea-level rise.

Healthcare4VideoStorm: Making Smart Decisions Based on Storm Metrics.

PubMed

Zhang, Weishan; Duan, Pengcheng; Chen, Xiufeng; Lu, Qinghua

2016-04-23

Storm-based stream processing is widely used for real-time large-scale distributed processing. Knowing the run-time status and ensuring performance is critical to providing expected dependability for some applications, e.g., continuous video processing for security surveillance. The existing scheduling strategies' granularity is too coarse to have good performance, and mainly considers network resources without computing resources while scheduling. In this paper, we propose Healthcare4Storm, a framework that finds Storm insights based on Storm metrics to gain knowledge from the health status of an application, finally ending up with smart scheduling decisions. It takes into account both network and computing resources and conducts scheduling at a fine-grained level using tuples instead of topologies. The comprehensive evaluation shows that the proposed framework has good performance and can improve the dependability of the Storm-based applications.

The threshold between storm overwash and inundation and the implication to paleo-storm records and climate signatures.

NASA Astrophysics Data System (ADS)

Smith, C. G.; Long, J.; Osterman, L. E.; Plant, N. G.; Marot, M. E.; Bernier, J.; Flocks, J. G.; Adams, C. S.

2014-12-01

In modern coastal systems, the sensitivity of a coastal site to erosion or deposition during storm conditions depends largely on the geomorphic configuration (e.g. dune or beach height and width) and the storm-induced oceanographic processes (surge and waves). Depending on the magnitude of these variables, coastal systems may be eroded, overwashed, breached, and/or inundated during the storm. To date, there has been no attempt to evaluate how these observable modern differences in storm-impact regimes might be utilized to interpret paleo-storm intensities and frequencies. Time-series of sediment texture, radioisotopic, and foraminiferal data from back-barrier environments along the Chandeleur Islands (Louisiana, USA) document the emplacement of a storm event deposit from Hurricane Isaac and we use this event to test paleo-storm intensity reconstruction methods. Water level reconstructed for the event layer using an advection (grain-size) settling model are 2 - 3 times greater than measured during the storm. The over-estimation is linked to the reconstruction model's assumptions concerning sediment transport during storms (i.e., overwash only), while actual processes included inundation as well. These contrasts may result in misidentification (i.e., presence/absence) and/or misclassification (i.e., intensity) of storms in the geologic record (e.g., low geomorphic conditions and high water levels) that would in turn affect the ability to link storm frequency or intensity to climatic drivers.

GPS Detection of Biot's Slow Wave in the Earth's Crust Triggered by Hurricane Sandy

NASA Astrophysics Data System (ADS)

Holt, W. E.; Zhang, J. H.; Blewitt, G.; Yao, Z.

2017-12-01

Here we show, using 5-minute GPS data observed in northeast USA around the landfall of Hurricane Sandy of October 29-30, 2012, evidence of a highly-attenuated wave propagating in the Earth's crust over hundreds of km inland at 65 m/s with peak amplitudes as great as 12 cm. Such a phenomenon is consistent with Biot's slow wave being triggered by the associated 4-m storm surge, then propagating in a highly permeable crust with abundant fluid-saturated interconnected cracks. The vertical displacement field recorded on a dense network of continuous GPS stations (CORS network) shows strong attenuation with distance, and occurs at frequencies too low to be recorded by broad-band seismic sensors. To our knowledge, such a unique wave, with ultra-low frequency, slow wave speed, high amplitude, and strong attenuation, has never been measured before. The zenith tropospheric varies slowly over the 24 hours that bracket Hurricane Sandy landfall and there is no apparent relationship to the timing or duration of the downward displacement field that initiates during peak storm surge loading. Amplitudes are a factor of 10 higher than predicted by elastic models of static loading of the 4-m storm surge. Numerical simulations of a low frequency impulse (with duration of storm surge loading) on a homogenous porous medium filled with viscous fluid show an amplification of displacements 10 times larger than for a homogeneous elastic material with the same elastic properties as the poroelastic matrix. The low wave speed of 65 m/s and long period of 4 hours, requires an extremely high permeability (10-6 10-8 m2). Such a high permeability can exist in high-porosity media containing vast interconnected fractures. The high amplitude displacements generated by the dynamic influences of Hurricane Sandy, and other large magnitude storms, would generate significant time-dependent stress changes in the crust that might contribute to the observations of seismicity rate changes and slow slip phenomenon described previously for this and other major storm disturbances.

A New Approach for Identifying Ionospheric Gradients in the Context of the Gagan System

NASA Astrophysics Data System (ADS)

Kudala, Ravi Chandra

2012-10-01

The Indian Space Research Organization and the Airports Authority of India are jointly implementing the Global Positioning System (GPS) aided GEO Augmented Navigation (GAGAN) system in order to meet the following required navigation performance (RNP) parameters: integrity, continuity, accuracy, and availability (for aircraft operations). Such a system provides the user with orbit, clock, and ionospheric corrections in addition to ranging signals via the geostationary earth orbit satellite (GEOSAT). The equatorial ionization anomaly (EIA), due to rapid non-uniform electron-ion recombination that persists on the Indian subcontinent, causes ionospheric gradients. Ionospheric gradients represent the most severe threat to high-integrity differential GNSS systems such as GAGAN. In order to ensure integrity under conditions of an ionospheric storm, the following three objectives must be met: careful monitoring, error bounding, and sophisticated storm-front modeling. The first objective is met by continuously tracking data due to storms, and, on quiet days, determining precise estimates of the threat parameters from reference monitoring stations. The second objective is met by quantifying the above estimates of threat parameters due to storms through maximum and minimum typical thresholds. In the context GAGAN, this work proposes a new method for identifying ionospheric gradients, in addition to determining an appropriate upper bound, in order to sufficiently understand error during storm days. Initially, carrier phase data of the GAGAN network from Indian TEC stations for both storm and quiet days was used for estimating ionospheric spatial and temporal gradients (the vertical ionospheric gradient (σVIG) and the rate of the TEC index (ROTI), respectively) in multiple viewing directions. Along similar lines, using the carrier to noise ratio (C/N0) for the same data, the carrier to noise ratio index (σCNRI) was derived. Subsequently, the one-toone relationship between σVIG and σCNRI was examined. High values of σVIG were determined for strong noise signals and corresponded to minimal σCNRI, indicating poor phase estimations and, in turn, an erroneous location. On the other hand, low values of σVIG were produced for weak noise signals and corresponded to maximum σCNRI, indicating strong phase estimations and, in turn, accurate locations. In other words, if a gradient persists in the line of sight direction of GEOSAT for aviation users, the down link L- band signal itself becomes erroneous. As a result, the en-route aviation user fails to receive a SBAS correction message leading to deprivation for the main objective of GAGAN. On the other hand, since the proposed approach enhances the receivers of both the aviation user and the reference monitoring station in terms of their performance, based on σCNRI, the integrity of SBAS messages themselves can be analyzed and considered for forward corrections.

Physical Modeling of the Processes Responsible for the Mid-Latitude Storm Enhanced Plasma Density

NASA Astrophysics Data System (ADS)

Fuller-Rowell, T. J.; Maruyama, N.; Fedrizzi, M.; Codrescu, M.; Heelis, R. A.

2016-12-01

Certain magnetic local time sectors at mid latitudes see substantial increases in plasma density in the early phases of a geomagnetic storm. The St. Patrick's Day storms of 2013 and 2015 were no exception, both producing large increases of total electron content at mid latitudes. There are theories for the build up of the storm enhanced density (SED), but can current theoretical ionosphere-thermosphere coupled models actually reproduce the response for an actual event? Not only is it necessary for the physical model to contain the appropriate physics, they also have to be forced by the correct drivers. The SED requires mid-latitude zonal transport to provide plasma stagnation in sunlight to provide the production. The theory also requires a poleward drift perpendicular to the magnetic field to elevate the plasma out of the body of the thermosphere to regions of substantially less loss rate. It is also suggested that equatorward winds are necessary to further elevate the plasma to regions of reduced loss. However, those same winds are also likely to transport molecular nitrogen rich neutral gas equatorward, potentially canceling out the benefits of the neutral circulation. Observations of mid-latitude zonal plasma flow are first analyzed to see if this first necessary ingredient is substantiated. The drift observations are then used to tune the driver to determine if, with the appropriate electric field driver, the latest physical models can reproduce the substantial plasma build up. If it can, the simulation can also be used to assess the contribution of the equatorward meridional wind; are they an asset to the plasma build up, or does the enhanced molecular species they carry counteract their benefit.

Environmental and Water Quality Operational Studies: Proceedings of the DeGray Lake Symposium Held in Arkadelphia, Arkansas.

DTIC Science & Technology

1987-03-01

statistics for storm water quality variables and fractions of phosphorus, solids, and carbon are presented in Tables 7 and 8, respectively. The correlation...matrix and factor analysis (same method as used for baseflow) of storm water quality variables suggested three groups: Group I - TMG, TCA, TNA, TSI...models to predict storm water quality . The 11 static and 3 dynamic storm variables were used as potential dependent variables. All independent and

Overview of U.S. EPA Office of Research and Development’s planned research on Analysis and monitoring in fresh and coastal/estuarine environments

EPA Science Inventory

Several factors are contributing to the development of the “perfect” Harmful algal Bloom (HAB) storm. For example, climate change associated with elevated temperatures over prolonged time periods, changes in population demographics, agricultural land use linked to nit...

Virtual operating room for team training in surgery.

PubMed

Abelson, Jonathan S; Silverman, Elliott; Banfelder, Jason; Naides, Alexandra; Costa, Ricardo; Dakin, Gregory

2015-09-01

We proposed to develop a novel virtual reality (VR) team training system. The objective of this study was to determine the feasibility of creating a VR operating room to simulate a surgical crisis scenario and evaluate the simulator for construct and face validity. We modified ICE STORM (Integrated Clinical Environment; Systems, Training, Operations, Research, Methods), a VR-based system capable of modeling a variety of health care personnel and environments. ICE STORM was used to simulate a standardized surgical crisis scenario, whereby participants needed to correct 4 elements responsible for loss of laparoscopic visualization. The construct and face validity of the environment were measured. Thirty-three participants completed the VR simulation. Attendings completed the simulation in less time than trainees (271 vs 201 seconds, P = .032). Participants felt the training environment was realistic and had a favorable impression of the simulation. All participants felt the workload of the simulation was low. Creation of a VR-based operating room for team training in surgery is feasible and can afford a realistic team training environment. Copyright © 2015 Elsevier Inc. All rights reserved.

A Multiplicative Cascade Model for High-Resolution Space-Time Downscaling of Rainfall

NASA Astrophysics Data System (ADS)

Raut, Bhupendra A.; Seed, Alan W.; Reeder, Michael J.; Jakob, Christian

2018-02-01

Distributions of rainfall with the time and space resolutions of minutes and kilometers, respectively, are often needed to drive the hydrological models used in a range of engineering, environmental, and urban design applications. The work described here is the first step in constructing a model capable of downscaling rainfall to scales of minutes and kilometers from time and space resolutions of several hours and a hundred kilometers. A multiplicative random cascade model known as the Short-Term Ensemble Prediction System is run with parameters from the radar observations at Melbourne (Australia). The orographic effects are added through multiplicative correction factor after the model is run. In the first set of model calculations, 112 significant rain events over Melbourne are simulated 100 times. Because of the stochastic nature of the cascade model, the simulations represent 100 possible realizations of the same rain event. The cascade model produces realistic spatial and temporal patterns of rainfall at 6 min and 1 km resolution (the resolution of the radar data), the statistical properties of which are in close agreement with observation. In the second set of calculations, the cascade model is run continuously for all days from January 2008 to August 2015 and the rainfall accumulations are compared at 12 locations in the greater Melbourne area. The statistical properties of the observations lie with envelope of the 100 ensemble members. The model successfully reproduces the frequency distribution of the 6 min rainfall intensities, storm durations, interarrival times, and autocorrelation function.

Assessing and Mitigating Hurricane Storm Surge Risk in a Changing Environment

NASA Astrophysics Data System (ADS)

Lin, N.; Shullman, E.; Xian, S.; Feng, K.

2017-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

The storm-time assessment of GNSS-SBAS performance within low latitude African region using a testbed-like platform

NASA Astrophysics Data System (ADS)

Abe, O. E.; Paparini, C.; Ngaya, R. H.; Otero Villamide, X.; Radicella, S. M.; Nava, B.

2017-09-01

A Satellite Based Augmentation System (SBAS) is designed to improve Global Navigation Satellite Systems (GNSS) in terms of integrity, accuracy, availability and continuity. The main limitation to SBAS performance optimization is the ionosphere, and this is more critical in low latitude. During geomagnetically disturbed periods the role of storm-time winds is important because they modify the atmospheric composition toward low latitudes. An index of ionospheric disturbance, the relative percentage of deviation of the vertical Total Electron Content (TEC) from the quiet level (DvTEC) at each station was evaluated to study positive and negative phases of the geomagnetic storms. The rate of change of TEC index (ROTI) over all the GNSS stations was estimated to evaluate equatorial ionospheric gradients and irregularities. From the study it is observed that the positive deviations are more frequent than negative ones. The availability map, which is the mean of the combine Vertical Protection Level (VPL) and Horizontal Protection Level (HPL) are used for the SBAS performance. The cases of moderate and minor storms studied during the months of July and October 2013 showed that the SBAS system performance during the disturbed periods depends on the local time in which the storm occurs, geographic longitude and other phenomena that need further study. During the storm-time conditions considered, three out of seven geomagnetic storms indicated good SBAS performance and exceed monthly average of the availability map, three geomagnetic storms reduced the system performance below monthly average while one does not have effect on SBAS system performance in respect to monthly average. The present study indicates ROTI as a better proxy than geomagnetic indices for the assessment of storm-time effects on GNSS-SBAS performance.

(abstract) Application of the GPS Worldwide Network in the Study of Global Ionospheric Storms

NASA Technical Reports Server (NTRS)

Ho, C. M.; Mannucci, A. J.; Lindqwister, U. J.; Pi, X.; Sparks, L. C.; Rao, A. M.; Wilsion, B. D.; Yuan, D. N.; Reyes, M.

1997-01-01

Ionospheric storm dynamics as a response to the geomagnetic storms is a very complicated global process involving many different mechanisms. Studying ionospheric storms will help us to understand the energy coupling process between the Sun and Earth and possibly also to effectively forecast space weather changes. Such a study requires a worldwide monitoring system. The worldwide GPS network, for the first time, makes near real-time global ionospheric TEC measurements a possibility.

Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

USGS Publications Warehouse

Haase, K.B.; Jordan, C.; Mentis, E.; Cottrell, L.; Mayne, H.R.; Talbot, R.; Sive, B.C.

2011-01-01

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the ongoing monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ?? 0.21 ppbv, a factor of 93 % above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km-2 h -1 compared to an estimated clear weather rate of 116 to 193 g km-2 h-1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols. ?? 2011 Author(s).

Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

USGS Publications Warehouse

Haase, Karl B.; Jordan, C.; Mentis, E.; Cottrell, L.; Mayne, H.R.; Talbot, R.; Sive, B.C.

2011-01-01

Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ?? 0.21 ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km-2 h -1 compared to an estimated clear weather rate of 116 to 193 g km-2 h-1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

Farm factors associated with reducing Cryptosporidium loading in storm runoff from dairies.

PubMed

Miller, W A; Lewis, D J; Pereira, M D G; Lennox, M; Conrad, P A; Tate, K W; Atwill, E R

2008-01-01

A systems approach was used to evaluate environmental loading of Cryptosporidium oocysts on five coastal dairies in California. One aspect of the study was to determine Cryptosporidium oocyst concentrations and loads for 350 storm runoff samples from dairy high use areas collected over two storm seasons. Selected farm factors and beneficial management practices (BMPs) associated with reducing the Cryptosporidium load in storm runoff were assessed. Using immunomagnetic separation (IMS) with direct fluorescent antibody (DFA) analysis, Cryptosporidium oocysts were detected on four of the five farms and in 21% of storm runoff samples overall. Oocysts were detected in 59% of runoff samples collected near cattle less than 2 mo old, while 10% of runoff samples collected near cattle over 6 mo old were positive. Factors associated with environmental loading of Cryptosporidium oocysts included cattle age class, 24 h precipitation, and cumulative seasonal precipitation, but not percent slope, lot acreage, cattle stocking number, or cattle density. Vegetated buffer strips and straw mulch application significantly reduced the protozoal concentrations and loads in storm runoff, while cattle exclusion and removal of manure did not. The study findings suggest that BMPs such as vegetated buffer strips and straw mulch application, especially when placed near calf areas, will reduce environmental loading of fecal protozoa and improve stormwater quality. These findings are assisting working dairies in their efforts to improve farm and ecosystem health along the California coast.

Analysis of large boulders along the coast of south-eastern Sicily to discriminate between storm and tsunami deposits.

NASA Astrophysics Data System (ADS)

Pirrotta, Claudia; Serafina Barbano, Maria; Gerardi, Flavia

2010-05-01

We present a study to discriminate the kind of anomalous waves, storms or tsunamis, that were responsible for the large boulder accumulation in the Vendicari Reserve along the south-eastern Sicilian coast. These depositional and erosional indicators of the large wave impact have been already observed in some rocky coasts of the Mediterranean basin and associated to strong waves of tsunamigenic or meteorological origin. Distinguishing boulders deposited by tsunamis from that deposited by storms and determining the age of their deposition can help to evaluate the magnitude and frequency of tsunamis and the hazard along the coast also regarding extraordinarily violent storms. The Sicilian Ionian coast has been affected in historical time by large destructive earthquake-related tsunamis (e.g. the 1169, 1693 and 1908) and it is exposed to an intense wave motion coming from a NNE- SSE span direction . In the rocky coastal area of Vendicari Reserve, three different GPS surveys (from September 2006 until April 2009) have been performed with the aim to observe the distance of each boulders with respect to the shoreline and if storms removed boulders or deposited new ones. A morphological analysis aiming to identify boulder shapes, measuring their volumes, elongation axis azimuth, pre-transport setting and the probable transport mechanism on the platform, was also carried out. The calcarenitic boulders (specific weight about 2,3 g/cm3), reaching about 20 tons and a distance up to 60m from the shoreline, are generally carved out from the supratidal or mid-sublittoral zone, showing widespread biogenic encrustations sometimes so fresh that suggest a recent deposition. The GPS surveys allowed us to observed that, after a strong storm during January 2009, several boulders were removed while new have been deposited on the platform by the storm waves. Hydrodynamic equations jointly to statistical analysis of sea storms have been used to determine the extreme event, geological or meteorological, responsible for this singular accumulation. We computed the minimum wave height, of storm and tsunami, required to start the movement of each boulder from its initial position. Moreover, we calculated the maximum penetration of the waves for the two major storm waves estimated at Vendicari and for the 1693 and 1908 tsunami waves. Finally we compared the computed values with the boulder distribution. The results show that the strongest storms were probably responsible for the current distribution of many boulders but about the 30% of them need of stronger waves, likely tsunami waves, than the maximum assumed storms to be moved and transported in their final place. Radiocarbon dating, performed on three probably tsunami boulders, having weight of about 15 t and sited at a distance >40 m from the shoreline, suggests that two of them were probably deposited by the 1693 tsunami, and one by a tsunami occurred after 650-930 AD that could be an unknown event or one of the historical tsunamis occurred in the Ionian coast of Sicily. Absolute age dating, such as optical stimulated luminescence, should be necessary to gather a correct imprint of the paleotsunami event.

Nighttime atmospheric stability changes and their effects on the temporal intensity of a mesoscale convective complex

NASA Technical Reports Server (NTRS)

Hovis, Jeffrey S.; Brundidge, Kenneth C.

1987-01-01

A method of interpolating atmospheric soundings while reducing the errors associated with simple time interpolation was developed. The purpose of this was to provide a means to determine atmospheric stability at times between standard soundings and to relate changes in stability to intensity changes in an MCC. Four MCC cases were chosen for study with this method with four stability indices being included. The discussion centers on three aspects for each stability parameter examined: the stability field in the vicinity of the storm and its changes in structure and magnitude during the lifetime of the storm, the average stability within the storm boundary as a function of time and its relation to storm intensity, and the apparent flux of stability parameter into the storm as a consequence of low-level storm relative flow. It was found that the results differed among the four stability parameters, sometimes in a conflicting fashion. Thus, an interpolation of how the storm intensity is related to the changing environmental stability depends upon the particular index utilized. Some explanation for this problem is offered.

Ring Current Response to Different Storm Drivers. Van Allen Probes and Cluster Observations.

NASA Astrophysics Data System (ADS)

Bingham, S.; Mouikis, C.; Kistler, L. M.; Spence, H. E.; Gkioulidou, M.; Claudepierre, S. G.; Farrugia, C. J.

2015-12-01

The ring current responds differently to the different solar and interplanetary storm drivers such as coronal mass injections, (CME's), co-rotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure change the global magnetic field, which affects the transport of the radiation belts. In order to determine the field changes during a storm it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. The source population of the storm time ring current is the night side plasma sheet. However, it is not clear how these convecting particles affect the storm time ring current pressure development. We use Van Allen Probes and Cluster observations together with the Volland-Stern and dipole magnetic field models to determine the contribution in the ring current pressure of the plasma sheet particles convecting from the night side that are on open drift paths, during the storm evolution. We compare storms that are related to different interplanetary drivers, CME and CIR, as observed at different local times.

Dust Storm Feature Identification and Tracking from 4D Simulation Data

NASA Astrophysics Data System (ADS)

Yu, M.; Yang, C. P.

2016-12-01

Dust storms cause significant damage to health, property and the environment worldwide every year. To help mitigate the damage, dust forecasting models simulate and predict upcoming dust events, providing valuable information to scientists, decision makers, and the public. Normally, the model simulations are conducted in four-dimensions (i.e., latitude, longitude, elevation and time) and represent three-dimensional (3D), spatial heterogeneous features of the storm and its evolution over space and time. This research investigates and proposes an automatic multi-threshold, region-growing based identification algorithm to identify critical dust storm features, and track the evolution process of dust storm events through space and time. In addition, a spatiotemporal data model is proposed, which can support the characterization and representation of dust storm events and their dynamic patterns. Quantitative and qualitative evaluations for the algorithm are conducted to test the sensitivity, and capability of identify and track dust storm events. This study has the potential to assist a better early warning system for decision-makers and the public, thus making hazard mitigation plans more effective.

Coupled effects of wind-storms and drought on tree mortality across 115 forest stands from the Western Alps and the Jura mountains.

PubMed

Csilléry, Katalin; Kunstler, Georges; Courbaud, Benoît; Allard, Denis; Lassègues, Pierre; Haslinger, Klaus; Gardiner, Barry

2017-12-01

Damage due to wind-storms and droughts is increasing in many temperate forests, yet little is known about the long-term roles of these key climatic factors in forest dynamics and in the carbon budget. The objective of this study was to estimate individual and coupled effects of droughts and wind-storms on adult tree mortality across a 31-year period in 115 managed, mixed coniferous forest stands from the Western Alps and the Jura mountains. For each stand, yearly mortality was inferred from management records, yearly drought from interpolated fields of monthly temperature, precipitation and soil water holding capacity, and wind-storms from interpolated fields of daily maximum wind speed. We performed a thorough model selection based on a leave-one-out cross-validation of the time series. We compared different critical wind speeds (CWSs) for damage, wind-storm, and stand variables and statistical models. We found that a model including stand characteristics, drought, and storm strength using a CWS of 25 ms -1 performed the best across most stands. Using this best model, we found that drought increased damage risk only in the most southerly forests, and its effect is generally maintained for up to 2 years. Storm strength increased damage risk in all forests in a relatively uniform way. In some stands, we found positive interaction between drought and storm strength most likely because drought weakens trees, and they became more prone to stem breakage under wind-loading. In other stands, we found negative interaction between drought and storm strength, where excessive rain likely leads to soil water saturation making trees more susceptible to overturning in a wind-storm. Our results stress that temporal data are essential to make valid inferences about ecological impacts of disturbance events, and that making inferences about disturbance agents separately can be of limited validity. Under projected future climatic conditions, the direction and strength of these ecological interactions could also change. © 2017 John Wiley & Sons Ltd.

Extremes of Extra-tropical Storms and Drivers of Variability on Different Time Scales

NASA Astrophysics Data System (ADS)

Leckebusch, G. C.

2015-12-01

Extreme extra-tropical cyclones are highly complex dynamical systems with relevance not only for the meteorological and climatological conditions themselves, but also for impacts on different sectors of society and economy. In this presentation latest research results to severe cyclones and related wind fields from synoptic to multi-decadal and anthropogenic scales will be presented, including recent work to risk assessment of potential damages out of this natural hazard. Nevertheless, the focus is laid on the seasonal timescale and recent results to predictability and predictive skills out of different forecast suites will be discussed. In this context, three seasonal forecast suites, namely ECMWF System 3, ECMWF System 4 and Met Office HadGEM-GA3, are analysed regarding their ability to represent wintertime extra-tropical cyclone and wind storm events for the period 1992 until 2011. Two objective algorithms have been applied to 6 hourly MSLP data and 12 hourly wind speeds in 925hPa to detect cyclone and wind storm events, respectively. Results show that all model suites are able to simulate the climatological mean distribution of cyclones and wind storms. For wind storms, all model suites show positive skill in simulating the inter-annual variability over the sub-tropical Pacific. Results for the Atlantic region are more model dependent, with all models showing negative correlations over the western Atlantic. Over the eastern Atlantic/Western Europe only HadGEM-GA3 and ECMWF-S4 reveal significant positive correlations. However, it is found that results over this region are not robust in time for ECMWF-S4, as correlations drop if using 1982 until 2011 instead of 1992 until 2011. Factors of potential predictability will be discussed.

Measuring storm tide and high-water marks caused by Hurricane Sandy in New York: Chapter 2

USGS Publications Warehouse

Simonson, Amy E.; Behrens, Riley

2015-01-01

In response to Hurricane Sandy, personnel from the U.S. Geological Survey (USGS) deployed a temporary network of storm-tide sensors from Virginia to Maine. During the storm, real-time water levels were available from tide gages and rapid-deployment gages (RDGs). After the storm, USGS scientists retrieved the storm-tide sensors and RDGs and surveyed high-water marks. These data demonstrate that the timing of peak storm surge relative to astronomical tide was extremely important in southeastern New York. For example, along the south shores of New York City and western Suffolk County, the peak storm surge of 6–9 ft generally coincided with the astronomical high tide, which resulted in substantial coastal flooding. In the Peconic Estuary and northern Nassau County, however, the peak storm surge of 9 ft and nearly 12 ft, respectively, nearly coincided with normal low tide, which helped spare these communities from more severe coastal flooding.

The 2008 Super Tuesday Tornado Outbreak: Synthetic Dual Doppler Analysis of Contrasting Tornadic Storm Types

NASA Technical Reports Server (NTRS)

Knupp, Kevin R.; Coleman, Timothy; Carey, Larry; Peterson, Walt; Elkins, Calvin

2008-01-01

During the Super Tuesday Tornado Outbreak on 5-6 February, a significant number of storms passed within about 40 km of WSR-88D radars. This distance, combined with the significant motion vector (from the southwest at 20-25 m per second) of relatively steady storms, is amenable to a synthetic dual Doppler analysis during the times when the storms passed the WSR-88D locations. Nine storms will be analyzed using the SDD technique. The following table provides their general characteristics and nearest approach to the 88D radars. For this data set, storm structure ranges from isolated supercell to QLCS. Each storm will be analyzed for a 40-60 min period during passage by the WSR-88D radar to determine general storm properties. Analysis of high-resolution single Doppler data around the time of passage (plus or minus 30 min), combined with 1-2 SDD analyses, will be used to examine the kinematic structure of low-level circulations (e.g., mesocyclone, downdraft) and the relation to the parent storm. This analysis may provide insights on the fundamental differences between cyclonic circulations in supercell storms and those within QCLS's.

High accuracy satellite drag model (HASDM)

NASA Astrophysics Data System (ADS)

Storz, M.; Bowman, B.; Branson, J.

The dominant error source in the force models used to predict low perigee satellite trajectories is atmospheric drag. Errors in operational thermospheric density models cause significant errors in predicted satellite positions, since these models do not account for dynamic changes in atmospheric drag for orbit predictions. The Air Force Space Battlelab's High Accuracy Satellite Drag Model (HASDM) estimates and predicts (out three days) a dynamically varying high-resolution density field. HASDM includes the Dynamic Calibration Atmosphere (DCA) algorithm that solves for the phases and amplitudes of the diurnal, semidiurnal and terdiurnal variations of thermospheric density near real-time from the observed drag effects on a set of Low Earth Orbit (LEO) calibration satellites. The density correction is expressed as a function of latitude, local solar time and altitude. In HASDM, a time series prediction filter relates the extreme ultraviolet (EUV) energy index E10.7 and the geomagnetic storm index a p to the DCA density correction parameters. The E10.7 index is generated by the SOLAR2000 model, the first full spectrum model of solar irradiance. The estimated and predicted density fields will be used operationally to significantly improve the accuracy of predicted trajectories for all low perigee satellites.

High accuracy satellite drag model (HASDM)

NASA Astrophysics Data System (ADS)

Storz, Mark F.; Bowman, Bruce R.; Branson, Major James I.; Casali, Stephen J.; Tobiska, W. Kent

The dominant error source in force models used to predict low-perigee satellite trajectories is atmospheric drag. Errors in operational thermospheric density models cause significant errors in predicted satellite positions, since these models do not account for dynamic changes in atmospheric drag for orbit predictions. The Air Force Space Battlelab's High Accuracy Satellite Drag Model (HASDM) estimates and predicts (out three days) a dynamically varying global density field. HASDM includes the Dynamic Calibration Atmosphere (DCA) algorithm that solves for the phases and amplitudes of the diurnal and semidiurnal variations of thermospheric density near real-time from the observed drag effects on a set of Low Earth Orbit (LEO) calibration satellites. The density correction is expressed as a function of latitude, local solar time and altitude. In HASDM, a time series prediction filter relates the extreme ultraviolet (EUV) energy index E10.7 and the geomagnetic storm index ap, to the DCA density correction parameters. The E10.7 index is generated by the SOLAR2000 model, the first full spectrum model of solar irradiance. The estimated and predicted density fields will be used operationally to significantly improve the accuracy of predicted trajectories for all low-perigee satellites.

Flooding in the future--predicting climate change, risks and responses in urban areas.

PubMed

Ashley, R M; Balmforth, D J; Saul, A J; Blanskby, J D

2005-01-01

Engineering infrastructure is provided at high cost and is expected to have a useful operational life of decades. However, it is clear that the future is uncertain. Traditional approaches to designing and operating urban storm drainage assets have relied on past performance of natural systems and the ability to extrapolate this performance, together with that of the assets across the usable lifetime. Whether or not climate change is going to significantly alter future weather patterns in Europe, it is clear that it is now incumbent on designers and operators of storm drainage systems to prepare for greater uncertainty in the effectiveness of storm drainage systems. A recent U.K. Government study considered the potential effects of climate and socio-economic change in the U.K. in terms of four future scenarios and what the implications are for the performance of existing storm drainage facilities. In this paper the modelling that was undertaken to try to quantify the changes in risk, together with the effectiveness of responses in managing that risk, are described. It shows that flood risks may increase by a factor of almost 30 times and that traditional engineering measures alone are unlikely to be able to provide protection.

Observations of weak ionosphere disturbances on the Kharkov incoherent scatter radar

NASA Astrophysics Data System (ADS)

Cherniak, Iurii; Lysenko, Valery; Cherniak, Iurii

The ionosphere plasma characteristics are responding on variations of solar and magnetic activity, high-power processes in the Earth atmosphere and lithosphere. The research of an ionosphere structure and dynamics is important as for understanding physics of processes and radiophysical problems solution. The method of incoherent scatter (IS) of radiowaves allows determining experimentally as regular variations of electronic concentration Ne and concomitant ionosphere parameters, and their behaviour during natural and antropogeneous origin disturbances. The equipment and measurement technique, developed by authors, are allows obtaining reliable data about an ionosphere behaviour during various origin and intensity perturbations. Oservations results of main parameters IS signal and ionosphere plasma during weak magnetic storm, solar eclipse, ionosphere disturbances caused by start of the high-power rocket are presented. Experimentally obtained on the Kharkov IS radar altitude-temporary dependences of disturbed ionosphere plasma parameters during weak intensity magnetic storm 04-06 April 2006 (Kp = 5, Dst = -100 nTl) were adduced. During a main storm phase the positive perturbation was observed (Ne is increased in 1.3 times), April 5, at maximum Dst - negative perturbation (Ne is decreased in 1.6 times), April 6 - positive perturbation (the second positive storm phase - Ne was increased at 1.33 times). During negative ionosphere storm the height of a F2 layer maximum was increased on 30-40 km, ionic temperature in the day is increased on 150K, electronic temperature is increased on 600K. For date 29.03.2006, when take place partial Sun eclipse (disk shadow factor 73 During launch heavy class rocket "Proton-K" december 25, 2006 from Baikonur cosmodrome (distance up to a view point of 2500 km) the perturbations in close space were observed. By measurements results of ionosphere plasma cross-section two disturbed areas were registered. First was observed through 8 mines, and second - through 60 mines after start of the rocket. The altitude-temporary diagrams of ionosphere plasma cross-section distribution were adduced.

Evaluation of Soil Moisture, Storm Characteristics, and Their Influence on Storm Runoff and Water Yield at the Panola Mountain Research Watershed, Georgia, U.S.A.

NASA Astrophysics Data System (ADS)

Riley, J. W.; Aulenbach, B. T.

2015-12-01

Understanding the factors that control runoff processes is important for many aspects of water supply and ecosystem protection, especially during climatic extremes that result in flooding or droughts; potentially impacting human safety. Furthermore, having knowledge of the conditions during which runoff occurs contributes to the conceptual understanding of the hydrologic cycle and may improve parameterization of hydrologic models. We evaluated soil moisture, storm characteristics, and the subsequent runoff and water yield for 297 storms over an eight-year period at Panola Mountain Research Watershed to better understand runoff generation processes. Panola Mountain Research Watershed is a small (41-hectare), relatively undisturbed forested watershed near Atlanta, GA, U.S.A. Strong relations were observed between total precipitation for a given storm, deep (70 cm below surface) antecedent soil moisture content and the volume of runoff. However, the strength of the relations varied based on occurrence during the growing (April - September; 172 storms) or dormant (October - March; 125 storms) period. In general, soil moisture responded at a minimum of 15 cm depth for all but 18 events. In addition, we found storms that initiated a response of deep soil moisture (70 cm below surface) to be an important factor relating to storm runoff and water yield. Seventy percent of the dormant period storms generated a response at 70 cm depth compared to 58% of growing period storms. A stronger relation between soil moisture and water yield was noted during the dormant period and indicated that all storms that produced a water yield >12% occurred when deep pre-event soil moisture was >20%. Similar patterns were also present during the growing season with occasional intense thunderstorms also generating higher water yields even in the absence of high soil moisture. The importance of deep soil moisture likely reflects the overall status of watershed storage conditions.

Characteristics of the low latitude ionospheric storm in the East-Asian region

NASA Astrophysics Data System (ADS)

Zhao, B.; Wan, W.; Liu, L.

2009-04-01

First, an classification of ionospheric storm effects in the sub-equatorial ionization anomaly(SEIA) region at 120°E has been performed through the analysis of ionogram data at two ionosonde stations, Wuhan (114.4°, 30.5°) and Chung-Li (121.2°, 25°), and total electron content (TEC) derived from GPS network distributed around 120°E during the year 1999-2004. Three types of negative phase are identified. One is shown to be varied in phase of F-layer height variation and the other two out of phase. Two types of positive phase are also found. The mechanisms to cause these types of ionospheric effects has been considered to be related with storm meridional thermospheric wind including traveling atmosphere disturbance(TAD), electric fields and composition changes. Then based on the 50 years of ionosonde and 8 years of global ionospheric maps (GIMs) data, features of low latitude ionospheric storm were obtained. Results shows that positive phases during 18:00-2400 LT with its center near the 21:00 LT and 24:00-08:00 LT with its center near the sunrise time have predomination in controlling the storm behavior at low latitudes. It is shown that the distortion of EIA under the effects of the above factors have significant influence on the behavior of SEIA ionogram parameters.

Observed and Simulated Radiative and Microphysical Properties of Tropical Convective Storms

NASA Technical Reports Server (NTRS)

DelGenio, Anthony D.; Hansen, James E. (Technical Monitor)

2001-01-01

Increases in the ice content, albedo and cloud cover of tropical convective storms in a warmer climate produce a large negative contribution to cloud feedback in the GISS GCM. Unfortunately, the physics of convective upward water transport, detrainment, and ice sedimentation, and the relationship of microphysical to radiative properties, are all quite uncertain. We apply a clustering algorithm to TRMM satellite microwave rainfall retrievals to identify contiguous deep precipitating storms throughout the tropics. Each storm is characterized according to its size, albedo, OLR, rain rate, microphysical structure, and presence/absence of lightning. A similar analysis is applied to ISCCP data during the TOGA/COARE experiment to identify optically thick deep cloud systems and relate them to large-scale environmental conditions just before storm onset. We examine the statistics of these storms to understand the relative climatic roles of small and large storms and the factors that regulate convective storm size and albedo. The results are compared to GISS GCM simulated statistics of tropical convective storms to identify areas of agreement and disagreement.

Developing Local Scale, High Resolution, Data to Interface with Numerical Storm Models

NASA Astrophysics Data System (ADS)

Witkop, R.; Becker, A.; Stempel, P.

2017-12-01

High resolution, physical storm models that can rapidly predict storm surge, inundation, rainfall, wind velocity and wave height at the intra-facility scale for any storm affecting Rhode Island have been developed by Researchers at the University of Rhode Island's (URI's) Graduate School of Oceanography (GSO) (Ginis et al., 2017). At the same time, URI's Marine Affairs Department has developed methods that inhere individual geographic points into GSO's models and enable the models to accurately incorporate local scale, high resolution data (Stempel et al., 2017). This combination allows URI's storm models to predict any storm's impacts on individual Rhode Island facilities in near real time. The research presented here determines how a coastal Rhode Island town's critical facility managers (FMs) perceive their assets as being vulnerable to quantifiable hurricane-related forces at the individual facility scale and explores methods to elicit this information from FMs in a format usable for incorporation into URI's storm models.

A simple metric to predict stream water quality from storm runoff in an urban watershed.

PubMed

Easton, Zachary M; Sullivan, Patrick J; Walter, M Todd; Fuka, Daniel R; Petrovic, A Martin; Steenhuis, Tammo S

2010-01-01

The contribution of runoff from various land uses to stream channels in a watershed is often speculated and used to underpin many model predictions. However, these contributions, often based on little or no measurements in the watershed, fail to appropriately consider the influence of the hydrologic location of a particular landscape unit in relation to the stream network. A simple model was developed to predict storm runoff and the phosphorus (P) status of a perennial stream in an urban watershed in New York State using the covariance structure of runoff from different landscape units in the watershed to predict runoff in time. One hundred and twenty-seven storm events were divided into parameterization (n = 85) and forecasting (n = 42) data sets. Runoff, dissolved P (DP), and total P (TP) were measured at nine sites distributed among three land uses (high maintenance, unmaintained, wooded), three positions in the watershed (near the outlet, midwatershed, upper watershed), and in the stream at the watershed outlet. The autocorrelation among runoff and P concentrations from the watershed landscape units (n = 9) and the covariance between measurements from the landscape units and measurements from the stream were calculated and used to predict the stream response. Models, validated using leave-one-out cross-validation and a forecasting method, were able to correctly capture temporal trends in streamflow and stream P chemistry (Nash-Sutcliffe efficiencies, 0.49-0.88). The analysis suggests that the covariance structure was consistent for all models, indicating that the physical processes governing runoff and P loss from these landscape units were stationary in time and that landscapes located in hydraulically active areas have a direct hydraulic link to the stream. This methodology provides insight into the impact of various urban landscape units on stream water quantity and quality.

Geomagnetic storms, the Dst ring-current myth and lognormal distributions

USGS Publications Warehouse

Campbell, W.H.

1996-01-01

The definition of geomagnetic storms dates back to the turn of the century when researchers recognized the unique shape of the H-component field change upon averaging storms recorded at low latitude observatories. A generally accepted modeling of the storm field sources as a magnetospheric ring current was settled about 30 years ago at the start of space exploration and the discovery of the Van Allen belt of particles encircling the Earth. The Dst global 'ring-current' index of geomagnetic disturbances, formulated in that period, is still taken to be the definitive representation for geomagnetic storms. Dst indices, or data from many world observatories processed in a fashion paralleling the index, are used widely by researchers relying on the assumption of such a magnetospheric current-ring depiction. Recent in situ measurements by satellites passing through the ring-current region and computations with disturbed magnetosphere models show that the Dst storm is not solely a main-phase to decay-phase, growth to disintegration, of a massive current encircling the Earth. Although a ring current certainly exists during a storm, there are many other field contributions at the middle-and low-latitude observatories that are summed to show the 'storm' characteristic behavior in Dst at these observatories. One characteristic of the storm field form at middle and low latitudes is that Dst exhibits a lognormal distribution shape when plotted as the hourly value amplitude in each time range. Such distributions, common in nature, arise when there are many contributors to a measurement or when the measurement is a result of a connected series of statistical processes. The amplitude-time displays of Dst are thought to occur because the many time-series processes that are added to form Dst all have their own characteristic distribution in time. By transforming the Dst time display into the equivalent normal distribution, it is shown that a storm recovery can be predicted with remarkable accuracy from measurements made during the Dst growth phase. In the lognormal formulation, the mean, standard deviation and field count within standard deviation limits become definitive Dst storm parameters.

Storm Identification and Tracking for Hydrologic Modeling Using Hourly Accumulated NEXRAD Precipitation Data

NASA Astrophysics Data System (ADS)

Olivera, F.; Choi, J.; Socolofsky, S.

2006-12-01

Watershed responses to storm events are strongly affected by the spatial and temporal patterns of rainfall; that is, the spatial distribution of the precipitation intensity and its evolution over time. Although real storms are moving entities with non-uniform intensities in both space and time, hydrological applications often synthesize these attributes by assuming storms that are uniformly distributed and have variable intensity according to a pre-defined hyetograph shape. As one considers watersheds of greater size, the non-uniformity of rainfall becomes more important, because a storm may not cover the watershed's entire area and may not stay in the watershed for its full duration. In order to incorporate parameters such as storm area, propagation velocity and direction, and intensity distribution in the definition of synthetic storms, it is necessary to determine these storm characteristics from spatially distributed precipitation data. To date, most algorithms for identifying and tracking storms have been applied to short time-step radar reflectivity data (i.e., 15 minutes or less), where storm features are captured in an effectively synoptic manner. For the entire United States, however, the most reliable distributed precipitation data are the one-hour accumulated 4 km × 4 km gridded NEXRAD data of the U.S. National Weather Service (NWS) (NWS 2005. The one-hour aggregation level of the data, though, makes it more difficult to identify and track storms than when using sequences of synoptic radar reflectivity data, because storms can traverse over a number of NEXRAD cells and change size and shape appreciably between consecutive data maps. In this paper, we present a methodology to overcome the identification and tracking difficulties and to extract the characteristics of moving storms (e.g. size, propagation velocity and direction, and intensity distribution) from one-hour accumulated distributed rainfall data. The algorithm uses Gaussian Mixture Models (GMM) for storm identification and image processing for storm tracking. The method has been successfully applied to Brazos County in Texas using the 2003 Multi-sensor Precipitation Estimator (MPE) NEXRAD rainfall data.

Energetics of the martian atmosphere using the Mars Analysis Correction Data Assimilation (MACDA) dataset

NASA Astrophysics Data System (ADS)

Battalio, Michael; Szunyogh, Istvan; Lemmon, Mark

2016-09-01

The energetics of the atmosphere of the northern hemisphere of Mars during the pre-winter solstice period are explored using the Mars Analysis Correction Data Assimilation (MACDA) dataset (v1.0) and the eddy kinetic energy equation, with the quasi-geostrophic omega equation providing vertical velocities. Traveling waves are typically triggered by geopotential flux convergence. The effect of dust on baroclinic instability is examined by comparing a year with a global-scale dust storm (GDS) to two years without a global-scale dust storm. During the non-GDS years, results agree with that of a previous study using a general circulation model simulation. In the GDS year, waves develop a mixed baroclinic/barotropic growth phase before decaying barotropically. Though the total amount of eddy kinetic energy generated by baroclinic energy conversion is lower during the GDS year, the maximum eddy intensity is not diminished. Instead, the number of intense eddies is reduced by about 50%.

ScienceCasts: A Display of Lights Above the Storm

NASA Image and Video Library

2017-10-10

Transient Luminous Events (TLEs) are flashes and glows that appear above storms and are results of activity occurring in and below those storms. Researchers are working to better understand lightning and thunderstorms, how they form and develop over time, and why storms produce different TLEs in different circumstances.

Storm loads of culturable and molecular fecal indicators in an inland urban stream.

PubMed

Liao, Hehuan; Krometis, Leigh-Anne H; Cully Hession, W; Benitez, Romina; Sawyer, Richard; Schaberg, Erin; von Wagoner, Emily; Badgley, Brian D

2015-10-15

Elevated concentrations of fecal indicator bacteria in receiving waters during wet-weather flows are a considerable public health concern that is likely to be exacerbated by future climate change and urbanization. Knowledge of factors driving the fate and transport of fecal indicator bacteria in stormwater is limited, and even less is known about molecular fecal indicators, which may eventually supplant traditional culturable indicators. In this study, concentrations and loading rates of both culturable and molecular fecal indicators were quantified throughout six storm events in an instrumented inland urban stream. While both concentrations and loading rates of each fecal indicator increased rapidly during the rising limb of the storm hydrographs, it is the loading rates rather than instantaneous concentrations that provide a better estimate of transport through the stream during the entire storm. Concentrations of general fecal indicators (both culturable and molecular) correlated most highly with each other during storm events but not with the human-associated HF183 Bacteroides marker. Event loads of general fecal indicators most strongly correlated with total runoff volume, maximum discharge, and maximum turbidity, while event loads of HF183 most strongly correlated with the time to peak flow in a hydrograph. These observations suggest that collection of multiple samples during a storm event is critical for accurate predictions of fecal indicator loading rates and total loads during wet-weather flows, which are required for effective watershed management. In addition, existing predictive models based on general fecal indicators may not be sufficient to predict source-specific genetic markers of fecal contamination. Copyright © 2015 Elsevier B.V. All rights reserved.

The case for a southeastern Australian Dust Bowl, 1895-1945

NASA Astrophysics Data System (ADS)

Cattle, Stephen R.

2016-06-01

Australia has an anecdotal history of severe wind erosion and dust storm activity, but there has been no lasting public perception of periods of extreme dust storm activity in this country, such as that developed in the USA following the Dust Bowl of the 1930s. Newspaper accounts of droughts and dust storms in southeastern (SE) Australia between 1895 and 1945 suggest that, at various times, the scale of these events was comparable to those experienced in the USA Dust Bowl. During this 50-year period, average annual rainfall values in this region were substantially below long-term averages, air temperatures were distinctly warmer, marginal lands were actively cropped and grazed, and rabbits were a burgeoning grazing pest. From the beginning of the Federation Drought of 1895-1902, dust storm activity increased markedly, with the downwind coastal cities of Sydney and Melbourne experiencing dust hazes, dust storms and falls of red rain relatively regularly. Between 1935 and 1945, Sydney and Melbourne received ten and nine long-distance dust events, respectively, with the years of 1938 and 1944/45 being the most intensely dusty. Entire topsoil horizons were blown away, sand drift was extreme, and crops and sheep flocks were destroyed. Although these periods of extreme dust storm activity were not as sustained as those experienced in the USA in the mid-1930s, there is a strong case to support the contention that SE Australia experienced its own extended, somewhat episodic version of a Dust Bowl, with a similar combination of causal factors and landscape effects.

Atmospheric structure and variability in areas of convective storms determined from 3-h rawinsonde data

NASA Technical Reports Server (NTRS)

Wilson, G. S.; Scoggins, J. R.

1976-01-01

The structure and variability of the atmosphere in areas of radar-observed convection were established by using 3-h rawinsonde and surface data from NASA's second Atmospheric Variability Experiment. Convective activity was shown to exist in areas where the low and middle troposphere is moist and the air is potentially and convectively unstable and has upward motion, in combination with positive moisture advection, at either the surface or within the boundary layer. The large variability of the parameters associated with convective storms over time intervals less than 12 h was also demonstrated so as to possibly produce a change in the probability of convective activity by a factor of 8 or more in 3 h. Between 30 and 60 percent of the total changes in parameters associated with convective activity over a 12-h period were shown to take place during a 3-h period. These large changes in parameters are related to subsynoptic-scale systems that often produce convective storms.

Elliptical storm cell modeling of digital radar data

NASA Technical Reports Server (NTRS)

Altman, F. J.

1972-01-01

A model for spatial distributions of reflectivity in storm cells was fitted to digital radar data. The data were taken with a modified WSR-57 weather radar with 2.6-km resolution. The data consisted of modified B-scan records on magnetic tape of storm cells tracked at 0 deg elevation for several hours. The MIT L-band radar with 0.8-km resolution produced cross-section data on several cells at 1/2 deg elevation intervals. The model developed uses ellipses for contours of constant effective-reflectivity factor Z with constant orientation and eccentricity within a horizontal cell cross section at a given time and elevation. The centers of the ellipses are assumed to be uniformly spaced on a straight line, with areas linearly related to log Z. All cross sections are similar at different heights (except for cell tops, bottoms, and splitting cells), especially for the highest reflectivities; wind shear causes some translation and rotation between levels. Goodness-of-fit measures and parameters of interest for 204 ellipses are considered.

Magnetosphere-Ionosphere Coupling and Associated Ring Current Energization Processes

NASA Technical Reports Server (NTRS)

Liemohn, M. W.; Khazanov, G. V.

2004-01-01

Adiabatic processes in the ring current are examined. In particular, an analysis of the factors that parameterize the net adiabatic energy gain in the inner magnetosphere during magnetic storms is presented. A single storm was considered, that of April 17, 2002. Three simulations were conducted with similar boundary conditions but with different electric field descriptions. It is concluded that the best parameter for quantifying the net adiabatic energy gain in the inner magnetosphere during storms is the instantaneous value of the product of the maximum westward electric field at the outer simulation boundary with the nightside plasma sheet density. However, all of the instantaneous magnetospheric quantities considered in this study produced large correlation coefficients. Therefore, they all could be considered useful predictors of the net adiabatic energy gain of the ring current. Long integration times over the parameters lessen the significance of the correlation. Finally, some significant differences exist in the correlation coefficients depending on the electric field description.

Factors affecting large peakflows on Appalachian watersheds: lessons from the Fernow Experimental Forest

Treesearch

James N. Kochenderfer; Mary Beth Adams; Gary W. Miller; David J. Helvey

2007-01-01

Data collected since 1951 on the Fernow Experimental Forest near Parsons, West Virginia, and at a gaging station on the nearby Cheat River since 1913 were used to evaluate factors affecting large peakflows on forested watersheds. Treatments ranged from periodic partial cuts to complete deforestation using herbicides. Total storm precipitation and average storm...

A FODO racetrack ring for nuSTORM: design and optimization

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

Liu, A.; Bross, A.; Neuffer, D.

2017-07-01

The goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ~ 480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize the arcmore » length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.« less

Thyroid Echography-induced Thyroid Storm and Exacerbation of Acute Heart Failure.

PubMed

Nakabayashi, Keisuke; Nakazawa, Naomi; Suzuki, Toshiaki; Asano, Ryotaro; Saito, Hideki; Nomura, Hidekimi; Isomura, Daichi; Okada, Hisayuki; Sugiura, Ryo; Oka, Toshiaki

2016-01-01

Hyperthyroidism and thyroid storm affect cardiac circulation in some conditions. Several factors including trauma can induce thyroid storms. We herein describe the case of a 57-year-old woman who experienced a thyroid storm and exacerbation of acute heart failure on thyroid echography. She initially demonstrated a good clinical course after medical rate control for atrial fibrillation; however, thyroid echography for evaluating hyperthyroidism led to a thyroid storm and she collapsed. A multidisciplinary approach stabilized her thyroid hormone levels and hemodynamics. Thus, the medical staff should be prepared for a deterioration in the patient's condition during thyroid echography in heart failure patients with hyperthyroidism.

Stalling Tropical Cyclones over the Atlantic Basin

NASA Astrophysics Data System (ADS)

Nielsen-Gammon, J. W.; Emanuel, K.

2017-12-01

Hurricane Harvey produced massive amounts of rain over southeast Texas and southwest Louisiana. Average storm total rainfall amounts over a 10,000 square mile (26,000 square km) area exceeded 30 inches (750 mm). An important aspect of the storm that contributed to the large rainfall totals was its unusual motion. The storm stalled shortly after making landfall, then moved back offshore before once again making landfall five days later. This storm motion permitted heavy rainfall to occur in the same general area for an extended period of time. The unusual nature of this event motivates an investigation into the characteristics and potential climate change influences on stalled tropical cyclones in the Atlantic basin using the HURDAT 2 storm track database for 1866-2016 and downscaled tropical cyclones driven by simulations of present and future climate. The motion of cyclones is quantified as the size of a circle circumscribing all storm locations during a given length of time. For a three-day period, Harvey remained inside a circle with a radius of 123 km. This ranks within the top 0.6% of slowest-moving historical storm instances. Among the 2% of slowest-moving storm instances prior to Harvey, only 13 involved storms that stalled near the continental United States coast, where they may have produced substantial rainfall onshore while tapping into marine moisture. Only two such storms stalled in the month of September, in contrast to 20 September stalls out of the 36 storms that stalled over the nearby open Atlantic. Just four of the stalled coastal storms were hurricanes, implying a return frequency for such storms of much less than once per decade. The synoptic setting of these storms is examined for common features, and historical and projected trends in occurrences of stalled storms near the coast and farther offshore are investigated.

Optical Observations of Lightning in Northern India Himalayan Mountain Countries and Tibet

NASA Technical Reports Server (NTRS)

Boeck, William L.; Mach, D. M.; Goodman, S. J.; Christian, Hugh J., Jr.

1999-01-01

This study summarizes the results of an analysis of data from the LIS instrument on the TRMM platform. The data for the Indian summer monsoon season is examined to study the seasonal patterns of the geographic and diurnal distribution of lightning storms. The storms on the Tibetan plateau show a single large diurnal peak at about 1400 local solar time. A region of Northern Pakistan has two storm peaks at 0200 and 1400 local solar time. The morning peak is half the magnitude of the afternoon peak. The region south of the Himalayan Mountains has a combined diurnal cycle in location and time of storm occurrence.

Optical Observations of Lightning in Northern India, Himalayan Mountain Countries and Tibet

NASA Technical Reports Server (NTRS)

Boeck, W. L.; Mach, D.; Goodman, S. J.; Christian, H. J., Jr.

1999-01-01

This study summarizes the results of an analysis of data from the LIS instrument on the TRMM platform. The data for the Indian summer monsoon season is examined to study the seasonal patterns of the geographic and diurnal distribution of lightning storms. The storms on the Tibetan plateau show a single large diurnal peak at about 1400 local solar time. A region of Northern Pakistan has two storm peaks at 0200 and 1400 local solar time. The morning peak is half the magnitude of the afternoon peak. The region south of the Himalayan Mountains has a combined diurnal cycle in location and time of storm occurrence.

Lightning rates relative to tornadic storm evolution on 22 May 1981

NASA Technical Reports Server (NTRS)

Macgorman, Donald R.; Burgess, Donald W.; Mazur, Vladislav; Rust, W. David; Taylor, William L.

1989-01-01

Lightning and Doppler radar data for two tornadic storms in Oklahoma on May 22, 1981 are used to analyze ground flash rates relative to the time of tornadoes. It is found that the ground flash rates had no obvious relationship with the tornado times, although the stroke rate in both storms was greatest after the tornadic stage ended. The variations in the cyclone shear and the intracloud flash rates within 10 km of the mesocyclone region are examined. The results suggest that most tornadic storms have an increase in total flash rates near the time of the tornado and that this increase is often dominated by intracloud flashes.

Hurricane Isaac: observations and analysis of coastal change

USGS Publications Warehouse

Guy, Kristy K.; Stockdon, Hilary F.; Plant, Nathaniel G.; Doran, Kara S.; Morgan, Karen L.M.

2013-01-01

Understanding storm-induced coastal change and forecasting these changes require knowledge of the physical processes associated with a storm and the geomorphology of the impacted coastline. The primary physical process of interest is sediment transport that is driven by waves, currents, and storm surge associated with storms. Storm surge, which is the rise in water level due to the wind, barometric pressure, and other factors, allows both waves and currents to impact parts of the coast not normally exposed to these processes. Coastal geomorphology reflects the coastal changes associated with extreme-storm processes. Relevant geomorphic variables that are observable before and after storms include sand dune elevation, beach width, shoreline position, sediment grain size, and foreshore beach slope. These variables, in addition to hydrodynamic processes, can be used to quantify coastal change and are used to predict coastal vulnerability to storms (Stockdon and others, 2007). The U.S. Geological Survey (USGS) National Assessment of Coastal Change Hazards (NACCH) project (http://coastal.er.usgs.gov/national-assessment/) provides hazard information to those concerned about the Nation’s coastlines, including residents of coastal areas, government agencies responsible for coastal management, and coastal researchers. Extreme-storm research is a component of the NACCH project (http://coastal.er.usgs.gov/hurricanes/) that includes development of predictive understanding, vulnerability assessments using models, and updated observations in response to specific storm events. In particular, observations were made to determine morphological changes associated with Hurricane Isaac, which made landfall in the United States first at Southwest Pass, at the mouth of the Mississippi River, at 0000 August 29, 2012 UTC (Coordinated Universal Time) and again, 8 hours later, west of Port Fourchon, Louisiana (Berg, 2013). Methods of observation included oblique aerial photography, airborne light detection and ranging (lidar) topographic surveys, and ground-based topographic surveys. This report documents data-collection efforts and presents qualitative and quantitative descriptions of hurricane-induced changes to the shoreline, beaches, dunes, and infrastructure in the region that was heavily impacted by Hurricane Isaac. The report is divided into the following sections: Section 1: Introduction Section 2: Storm Overview, presents a synopsis of the storm, including meteorological evolution, wind speed impact area, wind-wave generation, and storm-surge extent and magnitudes. Section 3: Coastal-Change Observations, describes data-collection missions, including acquisition of oblique aerial photography and airborne lidar topographic surveys, in response to Hurricane Isaac. Section 4: Coastal-Change Analysis, describes data-analysis methods and observations of coastal change.

Characterizing the Relationships Among Lightning and Storm Parameters: Lightning as a Proxy Variable

NASA Technical Reports Server (NTRS)

Goodman, S. J.; Raghavan, R.; William, E.; Weber, M.; Boldi, B.; Matlin, A.; Wolfson, M.; Hodanish, S.; Sharp. D.

1997-01-01

We have gained important insights from prior studies that have suggested relationships between lightning and storm growth, decay, convective rain flux, vertical distribution of storm mass and echo volume in the region, and storm energetics. A study was initiated in the Summer of 1996 to determine how total (in-cloud plus ground) lightning observations might provide added knowledge to the forecaster in the determination and identification of severe thunderstorms and weather hazards in real-time. The Melbourne Weather Office was selected as a primary site to conduct this study because Melbourne is the only site in the world with continuous and open access to total lightning (LDAR) data and a Doppler (WSR-88D) radar. A Lightning Imaging Sensor Data Applications Demonstration (LISDAD) system was integrated into the forecaster's workstation during the Summer 1996 to allow the forecaster to interact in real-time with the multi-sensor data being displayed. LISDAD currently ingests LDAR data, the cloud-to-ground National Lightning Detection Network (NLDN) data, and the Melbourne radar data in f real-time. The interactive features provide the duty forecaster the ability to perform quick diagnostics on storm cells of interest. Upon selection of a storm cell, a pop-up box appears displaying the time-history of various storm parameters (e.g., maximum radar reflectivity, height of maximum reflectivity, echo-top height, NLDN and LDAR lightning flash rates, storm-based vertically integrated liquid water content). This product is archived to aid on detailed post-analysis.

Development of an Agent Based Model to Estimate and Reduce Time to Restoration of Storm Induced Power Outages

NASA Astrophysics Data System (ADS)

Walsh, T.; Layton, T.; Mellor, J. E.

2017-12-01

Storm damage to the electric grid impacts 23 million electric utility customers and costs US consumers $119 billion annually. Current restoration techniques rely on the past experiences of emergency managers. There are few analytical simulation and prediction tools available for utility managers to optimize storm recovery and decrease consumer cost, lost revenue and restoration time. We developed an agent based model (ABM) for storm recovery in Connecticut. An ABM is a computer modeling technique comprised of agents who are given certain behavioral rules and operate in a given environment. It allows the user to simulate complex systems by varying user-defined parameters to study emergent, unpredicted behavior. The ABM incorporates the road network and electric utility grid for the state, is validated using actual storm event recoveries and utilizes the Dijkstra routing algorithm to determine the best path for repair crews to travel between outages. The ABM has benefits for both researchers and utility managers. It can simulate complex system dynamics, rank variable importance, find tipping points that could significantly reduce restoration time or costs and test a broad range of scenarios. It is a modular, scalable and adaptable technique that can simulate scenarios in silico to inform emergency managers before and during storm events to optimize restoration strategies and better manage expectations of when power will be restored. Results indicate that total restoration time is strongly dependent on the number of crews. However, there is a threshold whereby more crews will not decrease the restoration time, which depends on the total number of outages. The addition of outside crews is more beneficial for storms with a higher number of outages. The time to restoration increases linearly with increasing repair time, while the travel speed has little overall effect on total restoration time. Crews traveling to the nearest outage reduces the total restoration time, while crews going to the outage with most customers affected increases the overall restoration time but more quickly decreases the customers remaining without power. This model can give utility company managers the ability to optimize their restoration strategies before or during a storm event to reduce restoration times and costs.

Sensitivity of a Cloud-Resolving Model to Bulk and Explicit Bin Microphysical Schemes. Part 2; Cloud Microphysics and Storm Dynamics Interactions

NASA Technical Reports Server (NTRS)

Li, Xiaowen; Tao, Wei-Kuo; Khain, Alexander P.; Simpson, Joanne; Johnson, Daniel E.

2009-01-01

Part I of this paper compares two simulations, one using a bulk and the other a detailed bin microphysical scheme, of a long-lasting, continental mesoscale convective system with leading convection and trailing stratiform region. Diagnostic studies and sensitivity tests are carried out in Part II to explain the simulated contrasts in the spatial and temporal variations by the two microphysical schemes and to understand the interactions between cloud microphysics and storm dynamics. It is found that the fixed raindrop size distribution in the bulk scheme artificially enhances rain evaporation rate and produces a stronger near surface cool pool compared with the bin simulation. In the bulk simulation, cool pool circulation dominates the near-surface environmental wind shear in contrast to the near-balance between cool pool and wind shear in the bin simulation. This is the main reason for the contrasting quasi-steady states simulated in Part I. Sensitivity tests also show that large amounts of fast-falling hail produced in the original bulk scheme not only result in a narrow trailing stratiform region but also act to further exacerbate the strong cool pool simulated in the bulk parameterization. An empirical formula for a correction factor, r(q(sub r)) = 0.11q(sub r)(exp -1.27) + 0.98, is developed to correct the overestimation of rain evaporation in the bulk model, where r is the ratio of the rain evaporation rate between the bulk and bin simulations and q(sub r)(g per kilogram) is the rain mixing ratio. This formula offers a practical fix for the simple bulk scheme in rain evaporation parameterization.

A Comparison between Lightning Activity and Passive Microwave Measurements

NASA Technical Reports Server (NTRS)

Kevin, Driscoll T.; Hugh, Christian J.; Goodman, Steven J.

1999-01-01

A recent examination of data from the Lightning Imaging Sensor (LIS) and the TRMM Microwave Imager (TMI) suggests that storm with the highest frequency of lightning also possess the most pronounced microwave scattering signatures at 37 and 85 GHz. This study demonstrates a clear dependence between lightning and the passive microwave measurements, and accentuates how direct the relationship really is between cloud ice and lightning activity. In addition, the relationship between the quantity of ice content and the frequency of lightning (not just the presence of lightning) , is consistent throughout the seasons in a variety of regimes. Scatter plots will be presented which show the storm-averaged brightness temperatures as a function of the lightning density of the storms (L/Area) . In the 85 GHz and 37 GHz scatter plots, the brightness temperature is presented in the form Tb = k1 x log10(L/Area) + k2, where the slope of the regression, k1, is 58 for the 85 GHz relationship and 30.7 for the 37 GHz relationship. The regression for both these fits showed a correlation of 0.76 (r2 = 0.58), which is quite promising considering the simple procedure used to make the comparisons, which have not yet even been corrected for the view angle differences between the instruments, or the polarization corrections in the microwave imager.

Effect of intravenous amiodarone on QT and T peak-T end dispersions in patients with nonischemic heart failure treated with cardiac resynchronization-defibrillator therapy and electrical storm.

PubMed

Ogiso, Masataka; Suzuki, Atsushi; Shiga, Tsuyoshi; Nakai, Kenji; Shoda, Morio; Hagiwara, Nobuhisa

2015-02-01

The effect of intravenous amiodarone on spatial and transmural dispersion of ventricular repolarization in patients receiving cardiac resynchronization therapy (CRT) remains unclear. We studied 14 patients with nonischemic heart failure who received CRT with a defibrillator, experienced electrical storm and were treated with intravenous amiodarone. Each patient underwent 12-lead electrocardiography (ECG) and 187-channel repolarization interval-difference mapping electrocardiography (187-ch RIDM-ECG) before and during the intravenous administration of amiodarone infusion. A recurrence of ventricular tachyarrhythmia was observed in 2 patients during the early period of intravenous amiodarone therapy. Intravenous amiodarone increased the corrected QT interval (from 470±52 ms to 508±55 ms, P=0.003), but it significantly decreased the QT dispersion (from 107±35 ms to 49±27 ms, P=0.001), T peak-T end (Tp-e) dispersion (from 86±17 ms to 28±28 ms, P=0.001), and maximum inter-lead difference between corrected Tp-e intervals as measured by using the 187-ch RIDM-ECG (from 83±13 ms to 50±19 ms, P=0.001). Intravenous amiodarone suppressed the electrical storm and decreased the QT and Tp-e dispersions in patients treated by using CRT with a defibrillator.

Tracking Hurricane Wilma Across the Caribbean

NASA Technical Reports Server (NTRS)

2005-01-01

Information on cloud top heights at different stages in the life cycle of the rapidly intensifying Hurricane Wilma may prove useful for evaluating the ability of numerical weather models to predict the intensity changes of hurricanes. NASA's Multi-angle Imaging SpectroRadiometer (MISR) acquired this sequence of images and cloud-top height observations for Hurricane Wilma as it progressed across the Caribbean in October 2005. Each pair in the sequence has a photo-like view of the storm on the left and a matching color-coded image of cloud-top height on the right. Cloud-top heights range from 0 (purple) to 18 (red) kilometers altitude. Areas where cloud heights could not be determined are shown in dark gray.

The pair on the left show Wilma on Tuesday, October 18, when Hurricane watches were posted for Cuba and Mexico. The central pair shows the eye of Hurricane Wilma just hours before the storm began to cross the Yucatan Peninsula on Friday, October 21. At that time, Wilma was a powerful Category 4 Hurricane on the Saffir-Simpson scale, and had a minimum recorded central pressure of 930 millibars. Hurricane Wilma surged from tropical storm to Category 5 hurricane status in record time, but the storm slowed and weakened considerably after battering Mexico's Yucatan Peninsula and the Caribbean. The right-hand image pair displays the eastern edges of a weakened Wilma, when Wilma had been reduced to Category 2 status and was just starting to reach southern Florida on the morning of Sunday, October 23. Wilma gathered speed and strengthened on Sunday night, crossing Florida as a Category 3 storm on Monday, October 24.

On the 18th, Wilma looked a bit ragged. Its eye is located at the center of the left edge, and its outer bands of clouds appear to be dominated by a rather loose collection of thunderstorms. In the photo-like images, these look like areas of 'boiling clouds,' and in the cloud-height image, these appear as orange blobs, sometimes topped with pinkish-red. On October 21 (center), when Wilma was a Category 4 storm, cloud-top height on the eastern side of the storm near the eye reached 18 kilometers in altitude, with lower heights on the western side. The image from the 23rd shows the eastern edge of Wilma as it approached Florida (upper right) and Cuba (center right).

MISR has nine different cameras which view the Earth from a variety of angles. Shifts in the clouds' apparent position from one camera's perspective to another's allows MISR to measure the height of the cloud-tops. MISR scientists have programmed computers to compare the different views, identify features that appear to shift from view to view, and use that information to calculate cloud height automatically. The height fields pictured have not been corrected for the effects of cloud motion. Wind-corrected heights (which have higher accuracy but sparser spatial coverage) are within about 1 kilometer of the heights shown here.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously, viewing the entire globe between 82o north and 82o south latitude every nine days. Each image covers an area of about 380 kilometers by 1830 kilometers. The data products were generated from a portion of the imagery acquired during Terra orbits 31037, 31081 and 31110, and utilize data from within blocks 68-83 within World Reference System-2 paths 13, 16 and 18, respectively.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Science Mission Directorate, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is managed for NASA by the California Institute of Technology.

A new short-term forecasting model for the total electron content storm time disturbances

NASA Astrophysics Data System (ADS)

Tsagouri, Ioanna; Koutroumbas, Konstantinos; Elias, Panagiotis

2018-06-01

This paper aims to introduce a new model for the short-term forecast of the vertical Total Electron Content (vTEC). The basic idea of the proposed model lies on the concept of the Solar Wind driven autoregressive model for Ionospheric short-term Forecast (SWIF). In its original version, the model is operationally implemented in the DIAS system (http://dias.space.noa.gr) and provides alerts and warnings for upcoming ionospheric disturbances, as well as single site and regional forecasts of the foF2 critical frequency over Europe up to 24 h in advance. The forecasts are driven by the real time assessment of the solar wind conditions at ACE location. The comparative analysis of the variations in foF2 and vTEC during eleven geomagnetic storm events that occurred in the present solar cycle 24 reveals similarities but also differences in the storm-time response of the two characteristics with respect to the local time and the latitude of the observation point. Since the aforementioned dependences drive the storm-time forecasts of the SWIF model, the results obtained here support the upgrade of the SWIF's modeling technique in forecasting the storm-time vTEC variation from its onset to full development and recovery. According to the proposed approach, the vTEC storm-time response can be forecasted from 1 to 12-13 h before its onset, depending on the local time of the observation point at storm onset at L1. Preliminary results on the assessment of the performance of the proposed model and further considerations on its potential implementation in operational mode are also discussed.

Improvements of Storm Surge Modelling in the Gulf of Venice with Satellite Data: The ESA Due Esurge-Venice Project

NASA Astrophysics Data System (ADS)

De Biasio, F.; Bajo, M.; Vignudelli, S.; Papa, A.; della Valle, A.; Umgiesser, G.; Donlon, C.; Zecchetto, S.

2016-08-01

Among the most detrimental natural phenomena, storm surges heavily endanger the environment, the economy and the everyday life of sea-side countries and coastal zones. Considering that 120.000.000 people live in the Mediterranean area, with additional 200.000.000 presences in Summer for tourism purposes, the correct prediction of storm surges is crucial to avoid fatalities and economic losses. Earth Observation (EO) can play an important role in operational storm surge forecasting, yet it is not widely diffused in the storm surge community. In 2011 the European Space Agency (ESA), through its Data User Element (DUE) programme, financed two projects aimed at encouraging the uptake of EO data in this sector: eSurge and eSurge-Venice (eSV). The former was intended to address the issues of a wider users' community, while the latter was focused on a restricted geographical area: the northern Adriatic Sea and the Gulf of Venice. Among the objectives of the two projects there were a number of storm surge hindcast experiments using satellite data, to demonstrate the improvements on the surge forecast brought by EO. We report here the results of the hindcast experiments of the eSV project. They were aimed to test the sensitivity of a storm surge model to a forcing wind field modified with scatterometer data in order to reduce the bias between simulated and observed winds. Hindcast experiments were also performed to test the response of the storm surge model to the assimilation, with a dual 4D-Var system, of satellite altimetry observations as model errors of the initial state of the sea surface level. Remarkable improvements on the storm surge forecast have been obtained for what concerns the modified model wind forcing. Encouraging results have been obtained also in the assimilation experiments.

Monitoring Hurricane Rita Inland Storm Surge: Chapter 7J in Science and the storms-the USGS response to the hurricanes of 2005

USGS Publications Warehouse

McGee, Benton D.; Tollett, Roland W.; Goree, Burl B.

2007-01-01

Pressure transducers (sensors) are accurate, reliable, and cost-effective tools to measure and record the magnitude, extent, and timing of hurricane storm surge. Sensors record storm-surge peaks more accurately and reliably than do high-water marks. Data collected by sensors may be used in storm-surge models to estimate when, where, and to what degree stormsurge flooding will occur during future storm-surge events and to calibrate and verify stormsurge models, resulting in a better understanding of the dynamics of storm surge.

Storm Warnings on Lake Balaton,

DTIC Science & Technology

1982-04-06

times is called the storm duration. An independent wind period, or an independent storm, is that wind caused by a given synoptic system . However, within...mined for a long time ) there is no real physical basis from which to explain the existance of any characteristic differences. From r4 . the results... time , an essentially dynamic change takes place within the system , or we encounter a dull and slow barocline effect. Now in all these cases, an

Storm-Related Carbon Monoxide Poisoning: An Investigation of Target Audience Knowledge and Risk Behaviors.

PubMed

Damon, Scott A; Poehlman, Jon A; Rupert, Douglas J; Williams, Peyton N

Carbon monoxide (CO) poisonings in the United States consistently occur when residents improperly use portable gasoline-powered generators and other tools following severe storms and power outages. However, protective behaviors-such as installing CO alarms and placing generators more than 20 feet away from indoor structures-can prevent these poisonings. This study identified knowledge, attitudes, and beliefs that lead consumers to adopt risk and protective behaviors for storm-related CO poisoning and post-storm generator use. Four focus groups (32 participants in total) were conducted with generator owners in winter and summer storm-prone areas to explore home safety, portable generator use, CO poisoning knowledge, and generator safety messages. Discussions were transcribed, and findings analyzed using an ordered meta-matrix approach. Although most generator owners were aware of CO poisoning, many were unsure what constitutes a safe location for generator operation and incorrectly stated that enclosed areas outside the home-such as attached garages, sheds, and covered porches-were safe. Convenience and access to appliances often dictated generator placement. Participants were receptive to installing CO alarms in their homes but were unsure where to place them. These findings suggest a deficit in understanding how to operate portable generators safely and a need to correct misconceptions around safe placement. In terms of behavioral price, the simple installation and maintenance of inexpensive CO alarms may be the most important strategy for ultimately protecting homes from both storm-related and other CO exposures.

Storm-Related Carbon Monoxide Poisoning: An Investigation of Target Audience Knowledge and Risk Behaviors

PubMed Central

Damon, Scott A.; Poehlman, Jon A.; Rupert, Douglas J.; Williams, Peyton N.

2015-01-01

Carbon monoxide (CO) poisonings in the United States consistently occur when residents improperly use portable gasoline-powered generators and other tools following severe storms and power outages. However, protective behaviors—such as installing CO alarms and placing generators more than 20 feet away from indoor structures—can prevent these poisonings. This study identified knowledge, attitudes, and beliefs that lead consumers to adopt risk and protective behaviors for storm-related CO poisoning and post-storm generator use. Four focus groups (32 participants in total) were conducted with generator owners in winter and summer storm-prone areas to explore home safety, portable generator use, CO poisoning knowledge, and generator safety messages. Discussions were transcribed, and findings analyzed using an ordered meta-matrix approach. Although most generator owners were aware of CO poisoning, many were unsure what constitutes a safe location for generator operation and incorrectly stated that enclosed areas outside the home—such as attached garages, sheds, and covered porches—were safe. Convenience and access to appliances often dictated generator placement. Participants were receptive to installing CO alarms in their homes but were unsure where to place them. These findings suggest a deficit in understanding how to operate portable generators safely and a need to correct misconceptions around safe placement. In terms of behavioral price, the simple installation and maintenance of inexpensive CO alarms may be the most important strategy for ultimately protecting homes from both storm-related and other CO exposures. PMID:26345640

On using scatterometer and altimeter data to improve storm surge forecasting in the Adriatic Sea

NASA Astrophysics Data System (ADS)

Bajo, Marco; Umgiesser, Georg; De Biasio, Francesco; Vignudelli, Stefano; Zecchetto, Stefano

2017-04-01

Satellite data are seldom used in storm surge forecasting. Among the most important issues related to the storm surge forecasting are the quality of the model wind forcing and the initial condition of the sea surface elevation. In this work, focused on storm surge forecasting in the Adriatic Sea, satellite scatterometer wind data are used to correct the wind speed and direction biases of the ECMWF global atmospheric model by tuning the spatial fields, as an alternative to data assimilation. The capability of such an unbiased wind is tested against that of a high resolution wind, produced by a regional non-hydrostatic model. On the other hand, altimeter Total Water Level Envelope (TWLE) data, which provide the sea level elevation, are used to improve the accuracy of the initial state of the model simulations. This is done by assimilating into a storm surge model the TWLE obtained by the altimeter observations along ground tracks, after subtraction of the tidal components. In order to test the methodology, eleven storm surge events recorded in Venice, from 2008 to 2012, have been simulated using different configurations of forcing wind and altimeter data assimilation. Results show that the relative error on the estimation of the maximum surge peak, averaged over the cases considered, decreases from 13% to 7% using both the unbiased wind and the altimeter data assimilation, while forcing the hydrodynamic model with the high resolution wind (no tuning), the altimeter data assimilation reduces the error from 9% to 6%.

An outbreak of carbon monoxide poisoning after a major ice storm in Maine.

PubMed

Daley, W R; Smith, A; Paz-Argandona, E; Malilay, J; McGeehin, M

2000-01-01

Unintentional carbon monoxide (CO) exposure kills over 500 people in the U.S. annually. Outbreaks of CO poisoning have occurred after winter storms. The objective of this study was to describe clinical features and identify important risk factors of a CO poisoning outbreak occurring after a major ice storm. The study design included a case series of CO poisoning patients, a telephone survey of the general community, and a case-controlled study of households using specific CO sources. The setting was the primary service area of four hospital emergency departments located in the heavily storm-impacted interior region of Maine. Participants included all patients with a laboratory-confirmed diagnosis of CO poisoning during the 2 weeks after the storm onset, and a population-based comparison group of 522 households selected by random digit dialing. There were 100 cases identified, involving 42 common-source exposure incidents, most of them during the first week. Though classic CO symptoms of headache, dizziness, and nausea predominated, 9 patients presented with chest pain and 10 were asymptomatic. One patient died and 5 were transferred for hyperbaric oxygen therapy. Gasoline-powered electric generators were a CO source in 30 incidents, kerosene heaters in 8, and propane heaters in 4. In the community, 31.4% of households used a generator after the ice storm. The strongest risk factor for poisoning was locating a generator in a basement or an attached structure such as a garage. Cases of CO poisoning with various presentations can be expected in the early aftermath of a severe ice storm. Generators are a major CO source and generator location an important risk factor for such disasters.

3 CFR 8523 - Proclamation 8523 of May 20, 2010. National Hurricane Preparedness Week, 2010

Code of Federal Regulations, 2011 CFR

2011-01-01

... coastal and inland communities face the danger of these powerful storms. From high winds and storm surges... Preparedness Week, I urge individuals, families, communities, and businesses to take time to plan for the storm season before it begins. While hurricane forecasting has improved, storms may still develop with little...

Gold in the hills: patterns of placer gold accumulation under dynamic tectonic and climatic conditions

NASA Astrophysics Data System (ADS)

Roy, Sam; Upton, Phaedra; Craw, Dave

2018-01-01

Formation of placer accumulations in fluvial environments requires 103-106 or even greater times concentration of heavy minerals. For this to occur, regular sediment supply from erosion of adjacent topography is required, the river should remain within a single course for an extended period of time and the material must be reworked such that a high proportion of the sediment is removed while a high proportion of the heavy minerals remains. We use numerical modeling, constrained by observations of circum-Pacific placer gold deposits, to explore processes occurring in evolving river systems in dynamic tectonic environments. A fluvial erosion/transport model is used to determine the mobility of placer gold under variable uplift rate, storm intensity, and rock mass strength conditions. Gold concentration is calculated from hydraulic and bedload grain size conditions. Model results suggest that optimal gold concentration occurs in river channels that frequently approach a threshold between detachment-limited and transport-limited hydraulic conditions. Such a condition enables the accumulation of gold particles within the framework of a residual gravel lag. An increase in transport capacity, which can be triggered by faster uplift rates, more resistant bedrock, or higher intensity storm events, will strip all bedload from the channel. Conversely, a reduction in transport capacity, triggered by a reduction in uplift rate, bedrock resistance, or storm intensity, will lead to a greater accumulation of a majority of sediments and a net decrease in gold concentration. For our model parameter range, the optimal conditions for placer gold concentration are met by 103 times difference in strength between bedrock and fault, uplift rates between 1 and 5 mm a-1, and moderate storm intensities. Fault damage networks are shown to be a critical factor for high Au concentrations and should be a target for exploration.

Satellite navigation—Amazing technology but insidious risk: Why everyone needs to understand space weather

NASA Astrophysics Data System (ADS)

Hapgood, Mike

2017-04-01

Global navigation satellite systems (GNSS) are one of the technological wonders of the modern world. Popularly known as satellite navigation, these systems have provided global access to precision location and timing services and have thereby stimulated advances in industry and consumer services, including all forms of transport, telecommunications, financial trading, and even the synchronization of power grids. But this wonderful technology is at risk from natural phenomena in the form of space weather. GNSS signals experience a slight delay as they pass through the ionosphere. This delay varies with space weather conditions and is the most significant source of error for GNSS. Scientific efforts to correct these errors have stimulated billions of dollars of investment in systems that provide accurate correction data for suitably equipped GNSS receivers in a growing number of regions around the world. This accuracy is essential for GNSS use by aircraft and ships. Space weather also provides a further occasional but severe risk to GNSS: an extreme space weather event may deny access to GNSS as ionospheric scintillation scrambles the radio signals from satellites, and rapid ionospheric changes outstrip the ability of error correction systems to supply accurate corrections. It is vital that GNSS users have a backup for such occasions, even if it is only to hunker down and weather the storm.

Ionospheric redistribution during geomagnetic storms

PubMed Central

Immel, T J; Mannucci, A J

2013-01-01

[1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow. PMID:26167429

Ionospheric redistribution during geomagnetic storms.

PubMed

Immel, T J; Mannucci, A J

2013-12-01

[1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active ( D s t <-100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3-6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow.

An evaluation of nitrogen and phosphorus responses to rain events in a forested watershed

NASA Astrophysics Data System (ADS)

Steadman, C.; Argerich, A.; Bladon, K. D.; Johnson, S. L.

2017-12-01

Nitrogen (N) and phosphorus (P) exhibit differential responses to storm events which reflect complex, hydrologically-driven biogeochemical activity in a watershed. However, the magnitude of the responses change throughout the year indicating that they may be strongly influenced by antecedent precipitation conditions. To evaluate N and P responses to storms, we collected storm samples from four subwatersheds in a small forested watershed over a 12-month period as well as climate and hydrologic data. We quantified dissolved nitrate (NO3-), ammonium (NH4+), total dissolved nitrogen (TDN), soluble reactive phosphorus (SRP), and total dissolved phosphorus (TDP) concentrations and exports in 300 samples and examined responses across subwatersheds and storms. To assess the influence of potential drivers, we generated a series of models with discharge, instantaneous rain, and cumulative rain as explanatory variables for analyte concentrations. We also constructed models with cumulative rain as the explanatory variable for analyte exports. There was strong evidence (p < .05) that cumulative rain or the cumulative rain-subwatershed interaction were important for all analyte exports and concentrations. In contrast, evidence was weak for the significance of instantaneous rain for any analyte concentrations while discharge or the discharge-subwatershed interaction was significant for NO3- and NH4+, respectively. Of all factors, cumulative rain was the most relevant to explain analyte concentrations (i.e., showed the highest pseudo-R2), except for NH4+, for which discharge was more relevant. There was significant spatial and temporal variability for all analyte concentrations with the exception of NH4+, which showed little variability storm-to-storm. Maximum NO3- concentration occurred at the onset of the wet season while SRP had the lowest concentration during the same time period. Differential responses of analytes evidence distinct influences of hydrologically-driven biogeochemical activity on individual analytes. However, strong correlations with cumulative rain suggest that insight may be gained through consideration of coarser factors such as antecedent precipitation conditions which may serve to integrate complexities of the hillslope, improving understanding of N and P variability.

On the Role of Last Closed Drift Shell Dynamics in Driving Fast Losses and Van Allen Radiation Belt Extinction

NASA Astrophysics Data System (ADS)

Olifer, L.; Mann, I. R.; Morley, S. K.; Ozeke, L. G.; Choi, D.

2018-05-01

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ˜0.5-2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. We compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.

Extreme Storm Surges in the North Sea

NASA Astrophysics Data System (ADS)

Goennert, G.; Buß, Th.; Mueller, O.; Thumm, S.

2009-04-01

Extreme Storm Surges in the North Sea Gabriele Gönnert, Olaf Müller, Thomas Buß and Sigrid Thumm Climate Change will cause a rise of the sea level and probably more frequent and more violent storm surges. This has serious consequences for the safety of people as well as for their values and assets behind the dikes. It is therefore inevitable to first assess how sea level rise and an extreme storm surge event designes. In a second step it is possible to determine the risk for specific locations and develop strategies. The Project XtremRisk - Extreme Storm Surges at the North Sea Coast and in Estuaries. Risk calculation and risk strategies, funded by the German Federal Government will help answering these questions. The „Source-Pathway-Receptor" Concept will be used as a basis for risk analysis and development of new strategies. The Project offers methods to assess the development of extreme events under the conditions of today. Under conditions reflecting the climate change it will be tried to design an extreme event. For these three main points will be considered: a) Analysis and calculation of each factor, which produce a storm surge and its maximum level occurring in the last 100 years. These are: - maximum surge level: surge (due to the wind), - influence of the tide and the interaction between surge and tide, - influence of external surges , b) The hydrodynamics of a storm surge cause nonlinear effects in the interaction of the named factors. These factors and effects will both be taken into account to calculate the magnitude of the extreme storm surge. This step is very complex and need additional examination by numerical models. c) Analysis of the different scenarios to mean sea level rise and to the increase of wind speed due to the climate change. The presentation will introduce methods and show first results of the analysis of extreme events and the mean sea level rise.

Quantifying riverine and storm-surge flood risk by single-family residence: application to Texas.

PubMed

Czajkowski, Jeffrey; Kunreuther, Howard; Michel-Kerjan, Erwann

2013-12-01

The development of catastrophe models in recent years allows for assessment of the flood hazard much more effectively than when the federally run National Flood Insurance Program (NFIP) was created in 1968. We propose and then demonstrate a methodological approach to determine pure premiums based on the entire distribution of possible flood events. We apply hazard, exposure, and vulnerability analyses to a sample of 300,000 single-family residences in two counties in Texas (Travis and Galveston) using state-of-the-art flood catastrophe models. Even in zones of similar flood risk classification by FEMA there is substantial variation in exposure between coastal and inland flood risk. For instance, homes in the designated moderate-risk X500/B zones in Galveston are exposed to a flood risk on average 2.5 times greater than residences in X500/B zones in Travis. The results also show very similar average annual loss (corrected for exposure) for a number of residences despite their being in different FEMA flood zones. We also find significant storm-surge exposure outside of the FEMA designated storm-surge risk zones. Taken together these findings highlight the importance of a microanalysis of flood exposure. The process of aggregating risk at a flood zone level-as currently undertaken by FEMA-provides a false sense of uniformity. As our analysis indicates, the technology to delineate the flood risks exists today. © 2013 Society for Risk Analysis.

The First Fermi-GBM Terrestrial Gamma Ray Flash Catalog

NASA Astrophysics Data System (ADS)

Roberts, O. J.; Fitzpatrick, G.; Stanbro, M.; McBreen, S.; Briggs, M. S.; Holzworth, R. H.; Grove, J. E.; Chekhtman, A.; Cramer, E. S.; Mailyan, B. G.

2018-05-01

We present the first Fermi Space Telescope Gamma Ray Burst Monitor (GBM) catalog of 4,144 terrestrial gamma ray flashes (TGFs), detected since launch in 11 July 2008 through 31 July 2016. We discuss the updates and improvements to the triggered data and off-line search algorithms, comparing this improved detection rate of ˜800 TGFs per year with event rates from previously published TGF catalogs from other missions. A Bayesian block algorithm calculated the temporal and spectral properties of the TGFs, revealing a delay between the hard (>300 keV) and soft (≤300 keV) photons of around 27 μs. Detector count rates of "low-fluence" events were found to have average rates exceeding 150 kHz. Searching the World-Wide Lightning Location Network data for radio sferics within ±5 min of each TGF revealed a clean sample of 1,314 World-Wide Lightning Location Network locations, which were used to to accurately locate TGF-producing storms. It also revealed lightning and storm activity for specific regions, as well as seasonal and daily variations of global lightning patterns. Correcting for the orbit of Fermi, we quantitatively find a marginal excess of TGFs being produced from storms over land near oceans (i.e., narrow isthmuses and small islands). No difference was observed between the duration of TGFs over the ocean and land. The distribution of TGFs at a given local solar time for predefined American, Asian, and African regions were confirmed to correlate well with known regional lightning rates.

MicroRNA-302a suppresses influenza A virus-stimulated interferon regulatory factor-5 expression and cytokine storm induction.

PubMed

Chen, Xueyuan; Zhou, Li; Peng, Nanfang; Yu, Haisheng; Li, Mengqi; Cao, Zhongying; Lin, Yong; Wang, Xueyu; Li, Qian; Wang, Jun; She, Yinglong; Zhu, Chengliang; Lu, Mengji; Zhu, Ying; Liu, Shi

2017-12-29

During influenza A virus (IAV) infection, cytokine storms play a vital and critical role in clinical outcomes. We have previously reported that microRNA (miR)-302c regulates IAV-induced IFN expression by targeting the 3'-UTR of nuclear factor κB (NF-κB)-inducing kinase. In the current study, we found that miR-302a, another member of the miR-302 cluster, controls the IAV-induced cytokine storm. According to results from cell-based and knockout mouse models, IAV induces a cytokine storm via interferon regulatory factor-5 (IRF-5). We also found that IAV infection up-regulates IRF-5 expression and that IRF-5 in turn promotes IAV replication. Furthermore, we observed that IRF-5 is a direct target of miR-302a, which down-regulated IRF-5 expression by binding its 3'-UTR. Moreover, IAV increased IRF-5 expression by down-regulating miR-302a expression. Interestingly, miR-302a inhibited IAV replication. In IAV-infected patients, miR-302a expression was down-regulated, whereas IRF-5 expression was up-regulated. Taken together, our work uncovers and defines a signaling pathway implicated in an IAV-induced cytokine storm. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Reliability of windstorm predictions in the ECMWF ensemble prediction system

NASA Astrophysics Data System (ADS)

Becker, Nico; Ulbrich, Uwe

2016-04-01

Windstorms caused by extratropical cyclones are one of the most dangerous natural hazards in the European region. Therefore, reliable predictions of such storm events are needed. Case studies have shown that ensemble prediction systems (EPS) are able to provide useful information about windstorms between two and five days prior to the event. In this work, ensemble predictions with the European Centre for Medium-Range Weather Forecasts (ECMWF) EPS are evaluated in a four year period. Within the 50 ensemble members, which are initialized every 12 hours and are run for 10 days, windstorms are identified and tracked in time and space. By using a clustering approach, different predictions of the same storm are identified in the different ensemble members and compared to reanalysis data. The occurrence probability of the predicted storms is estimated by fitting a bivariate normal distribution to the storm track positions. Our results show, for example, that predicted storm clusters with occurrence probabilities of more than 50% have a matching observed storm in 80% of all cases at a lead time of two days. The predicted occurrence probabilities are reliable up to 3 days lead time. At longer lead times the occurrence probabilities are overestimated by the EPS.

Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico

Treesearch

A. C. Gellis; NO-VALUE

2013-01-01

The significant characteristics controlling the variability in storm-generated suspended-sediment loads and concentrations were analyzed for four basins of differing land use (forest, pasture, cropland, and urbanizing) in humid-tropical Puerto Rico. Statistical analysis involved stepwise regression on factor scores. The explanatory variables were attributes of flow,...

(abstract) Using GPS Measurements to Identify Global Ionospheric Storms in Near Real-Time

NASA Technical Reports Server (NTRS)

Ho, C. M.; Mannucci, A. J.; Lindqwister, U. J.; Rao, A. M.; Pi, X.; Wilson, B. D.; Yuan, D. N.; Reyes, M.

1996-01-01

The solar wind interacts with the Earth's magnetosphere, eventually dissipating energy into the ionosphere and atmosphere. As a terminator, the ionosphere responds to magnetic storms, which is very important in understanding the energy coupling process between the Sun and the Earth and in forecasting space weather changes.The worldwide GPS network, for the first time, makes near real-time global ionospheric TEC measurements a possibility. Based on these measurements, global ionospheric TEC maps are generated with time resolution of from 5 minutes to hours. Using these maps, we can analyze the global evolution of ionospheric storms on temporal and spatial scales, which have been dificult to study before. We find that for certain types of storms (such as TID-driven), it is possible to identify them near onset and issue warning signals during the early stages. Main attention has been paid on northern hemispheric winter storms. Their common features and physical mechanisms are being investigated.

The return periods and risk assessment of severe dust storms in Inner Mongolia with consideration of the main contributing factors.

PubMed

Liu, Xueqin; Li, Ning; Xie, Wei; Wu, Jidong; Zhang, Peng; Ji, Zhonghui

2012-09-01

This study presents a methodology for return period analysis and risk assessment of severe dust storm disaster. Meteorological observation data, soil moisture data, and remote sensing data from 30 meteorological stations in Inner Mongolia (western China) from 1985 to 2006 were used for the study. A composite index of severe dust storm disaster (Index I (SDS)) based on the influence mechanisms of the main contributing factors was developed by using the analytic hierarchy process and the weighted comprehensive method, and the hazard risk curves (i.e., the transcendental probability curves of I (SDS)) for the 30 stations were established using the parameter estimation method. We then analyzed the risk of the occurrence of severe dust storm under different scenarios of 5-, 10-, 20-, and 50-year return periods. The results show that the risk decreased from west to east across Inner Mongolia, and there are four severe dust storm occurrence peak value centers, including Guaizihu, Jilantai, Hailisu, and Zhurihe-Erenhot. The severity of dust storms in seven places will be intolerable in the 50-year return period scenario and in three places in the 20-year return period scenario. These results indicate that these locations should concentrate forces on disaster prevention, monitoring, and early warning. The I (SDS) was developed as an easily understandable tool useful for the assessment and comparison of the relative risk of severe dust storm disasters in different areas. The risk assessment was specifically intended to support local and national government agencies in their management of severe dust storm disasters in their efforts to (1) make resource allocation decisions, (2) make high-level planning decisions, and (3) raise public awareness of severe dust storm risk.

Differences in generation of magnetic storms driven by magnetic clouds, ejecta, sheath region before ICME and CIR

NASA Astrophysics Data System (ADS)

Nikolaeva, Nadezhda; Yermolaev, Yuri; Lodkina, Irina

2016-07-01

We investigate the efficiency of main phase storm generation by different solar wind (SW) streams when using 12 functions coupling (FC) various interplanetary parameters with magnetospheric state. By using our Catalog of Solar Wind Phenomena [Yermolaev et al., 2009] created on the basis of the OMNI database for 1976-2000, we selected the magnetic storms with Dst ≤ -50 nT for which interplanetary sources were following: MC (10 storms); Ejecta (31 storms); Sheath (21 storms); CIRs (31magnetic storms). To compare the interplanetary drivers we estimate an efficiency of magnetic storm generation by type of solar wind stream with using 12 coupling functions. We obtained that in average Sheath has more large efficiency of the magnetic storm generation and MC has more low efficiency in agreement with our previous results which show that by using a modification of formula by Burton et al. [1975] for connection of interplanetary conditions with Dst and Dst* indices the efficiency of storm generation by Sheath and CIR was ~50% higher than generation by ICME [Nikolaeva et al., 2013; 2015]. The most part of FCs has sufficiently high correlation coefficients. In particular the highest values of coefficients (~ 0.5 up to 0.63) are observed for Sheath- driven storms. In a small part of FCs with low coefficients it is necessary to increase the number of magnetic storms to increase the statistical significance of results. The reliability of the obtained data and possible reasons of divergences for various FCs and various SW types require further researches. The authors are grateful for the opportunity to use the OMNI database. This work was supported by the Russian Foundation for Basic Research, project 16-02-00125, and by Program of Presidium of the Russian Academy of Sciences. References: Nikolaeva, N. S., Y. I. Yermolaev, and I. G. Lodkina (2013), Modeling of Dst-index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Res., 51 (6), 401-412. Nikolaeva, N. S., Y. I. Yermolaev, and I. G. Lodkina (2015), Modeling of the corrected Dst* index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Res., 53(2), 119-127. Yermolaev, Yu. I., N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev (2009), Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, 47(2), 81-94.

Surface electric fields for North America during historical geomagnetic storms

USGS Publications Warehouse

Wei, Lisa H.; Homeier, Nichole; Gannon, Jennifer L.

2013-01-01

To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.

Profiles of Ionospheric Storm-enhanced Density during the 17 March 2015 Great Storm

NASA Astrophysics Data System (ADS)

Liu, J.; Wang, W.; Burns, A. G.; Yue, X.; Zhang, S.; Zhang, Y.

2015-12-01

Ionospheric F2 region peak densities (NmF2) are expected to show a positive phase correlation with total electron content (TEC), and electron density is expected to have an anti-correlation with electron temperature near the ionospheric F2 peak. However, we show that, during the 17 March 2015 great storm, TEC and F2 region electron density peak height (hmF2) over Millstone Hill increased, but the F2 region electron density peak (NmF2) decreased significantly during the storm-enhanced density (SED) phase of the storm compared with the quiet-time ionosphere. This SED occurred where there was a negative ionospheric storm near the F2 peak and below it. The weak ionosphere below the F2 peak resulted in much reduced downward heat conduction for the electrons, trapping the heat in the topside. This, in turn, increased the topside scale height, so that, even though electron densities at the F2 peak were depleted, TEC increased in the SED. The depletion in NmF2 was probably caused by an increase in the density of the molecular neutrals, resulting in enhanced recombination. In addition, the storm-time topside ionospheric electron density profile was much closer to diffusive equilibrium than non-storm time profile because of less daytime plasma flow from the ionosphere to the plasmasphere.

Dead-time Corrected Disdrometer Data

DOE Data Explorer

Bartholomew, Mary Jane

2008-03-05

Original and dead-time corrected disdrometer results for observations made at SGP and TWP. The correction is based on the technique discussed in Sheppard and Joe, 1994. In addition, these files contain calculated radar reflectivity factor, mean Doppler velocity and attenuation for every measurement for both the original and dead-time corrected data at the following wavelengths: 0.316, 0.856, 3.2, 5, and 10cm (W,K,X,C,S bands). Pavlos Kollias provided the code to do these calculations.

Storm-time radiation belt electron dynamics: Repeatability in the outer radiation belt

NASA Astrophysics Data System (ADS)

Murphy, K. R.; Mann, I. R.; Rae, J.; Watt, C.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.

2017-12-01

During intervals of enhanced solar wind driving the outer radiation belt becomes extremely dynamic leading to geomagnetic storms. During these storms the flux of energetic electrons can vary by over 4 orders of magnitude. Despite recent advances in understanding the nature of competing storm-time electron loss and acceleration processes the dynamic behavior of the outer radiation belt remains poorly understood; the outer radiation belt can exhibit either no change, an enhancement, or depletion in radiation belt electrons. Using a new analysis of the total radiation belt electron content, calculated from the Van Allen probes phase space density (PSD), we statistically analyze the time-dependent and global response of the outer radiation belt during storms. We demonstrate that by removing adiabatic effects there is a clear and repeatable sequence of events in storm-time radiation belt electron dynamics. Namely, the relativistic (μ=1000 MeV/G) and ultra-relativistic (μ=4000 MeV/G) electron populations can be separated into two phases; an initial phase dominated by loss followed by a second phase dominated by acceleration. At lower energies, the radiation belt seed population of electrons (μ=150 MeV/G) shows no evidence of loss but rather a net enhancement during storms. Further, we investigate the dependence of electron dynamics as a function of the second adiabatic invariant, K. These results demonstrate a global coherency in the dynamics of the source, relativistic and ultra-relativistic electron populations as function of the second adiabatic invariant K. This analysis demonstrates two key aspects of storm-time radiation belt electron dynamics. First, the radiation belt responds repeatably to solar wind driving during geomagnetic storms. Second, the response of the radiation belt is energy dependent, relativistic electrons behaving differently than lower energy seed electrons. These results have important implications in radiation belt research. In particular, the repeatability in electron dynamics coupled with observations of processes leading to electron loss (EMIC waves) and acceleration (VLF or ULF waves) can be used to diagnose the relative importance of physical processes in radiation belt dynamics during storms.

Multistep Dst development and ring current composition changes during the 4-6 June 1991 magnetic storm

NASA Astrophysics Data System (ADS)

Kozyra, J. U.; Liemohn, M. W.; Clauer, C. R.; Ridley, A. J.; Thomsen, M. F.; Borovsky, J. E.; Roeder, J. L.; Jordanova, V. K.; Gonzalez, W. D.

2002-08-01

The 4-6 June 1991 magnetic storm, which occurred during solar maximum conditions, is analyzed to investigate two observed features of magnetic storms that are not completely understood: (1) the mass-dependent decay of the ring current during the early recovery phase and (2) the role of preconditioning in multistep ring current development. A kinetic ring current drift-loss model, driven by dynamic fluxes at the nightside outer boundary, was used to simulate this storm interval. A strong partial ring current developed and persisted throughout the main and early recovery phases. The majority of ions in the partial ring current make one pass through the inner magnetosphere on open drift paths before encountering the dayside magnetopause. The ring current exhibited a three-phase decay in this storm. A short interval of charge-exchange loss constituted the first phase of the decay followed by a classical two-phase decay characterized by an abrupt transition between two very different decay timescales. The short interval dominated by charge-exchange loss occurred because an abrupt northward turning of the interplanetary magnetic field (IMF) trapped ring current ions on closed trajectories, and turned-off sources and ``flow-out'' losses. If this had been the end of the solar wind disturbance, decay timescales would have gradually lengthened as charge exchange preferentially removed the short-lived species; a distinctive two-phase decay would not have resulted. However, the IMF turned weakly southward, drift paths became open, and a standard two-phase decay ensued as the IMF rotated slowly northward again. As has been shown before, a two-phase decay is produced as open drift paths are converted to closed in a weakening convection electric field, driving a transition from the fast flow-out losses associated with the partial ring current to the slower charge-exchange losses associated with the trapped ring current. The open drift path geometry during the main phase and during phase 1 of the two-phase decay has important consequences for the evolution of ring current composition and for preconditioning issues. In this particular storm, ring current composition changes measured by the Combined Release and Radiation Effects Satellite (CRRES) during the main and recovery phase of the storm resulted largely from composition changes in the plasma sheet transmitted into the inner magnetosphere along open drift paths as the magnetic activity declined. Possible preconditioning elements were investigated during the multistep development of this storm, which was driven by the sequential arrival of three southward IMF Bz intervals of increasing peak strength. In each case, previous intensifications (preexisting ring currents) were swept out of the magnetosphere by the enhanced convection associated with the latest intensification and did not act as a significant preconditioning element. However, plasma sheet characteristics varied significantly between subsequent intensifications, altering the response of the magnetosphere to the sequential solar wind drivers. A denser plasma sheet (ring current source population) appeared during the second intensification, compensating for the weaker IMF Bz at this time and producing a minimum pressure-corrected Dst* value comparable to the third intensification (driven by stronger IMF Bz but a lower density plasma sheet source). The controlling influence of the plasma sheet dynamics on the ring current dynamics and its role in altering the inner magnetospheric response to solar wind drivers during magnetic storms adds a sense of urgency to understanding what processes produce time-dependent responses in the plasma sheet density, composition, and temperature.

Lightning Mapping Observations: What we are learning.

NASA Astrophysics Data System (ADS)

Krehbiel, P.

2001-12-01

The use of radio frequency time-of-arrival techniques for accurately mapping lightning discharges is revolutionizing our ability to study lightning discharge processes and to investigate thunderstorms. Different types of discharges are being observed that we have not been able to study before or knew existed. Included are a variety of inverted and normal polarity intracloud and cloud-to-ground discharges, frequent short-duration discharges at high altitude in storms and in overshooting convective tops, highly energetic impulsive discharge events, and horizontally extensive `spider' lightning discharges in large mesoscale convective systems. High time resolution measurements valuably complement interferometric observations and are starting to exceed the ability of interferometers to provide detailed pictures of flash development. Mapping observations can be used to infer the polarity of the breakdown channels and hence the location and sign of charge regions in the storm. The lightning activity in large, severe storms is found to be essentially continuous and volume-filling, with substantially more lightning inside the storm than between the cloud and ground. Spectacular dendritic structures are observed in many flashes. The lightning observations can be used to infer the electrical structure of a storm and therefore to study the electrification processes. The results are raising fundamental questions about how storms become electrified and how the electrification evolves with time. Supercell storms are commonly observed to electrify in an inverted or anomalous manner, raising questions about how these storms are different from normal storms, and even what is `normal'. The high lightning rates in severe storms raises the distinct possibility that the discharges themselves might be sustaining or enhancing the electrification. Correlated observations with radar, instrumented balloons and aircraft, and ground-based measurements are leading to greatly improved understanding of the electrical processes in storms. The mapping observations also provide possible diagnostics of storm type and severity. Lightning `holes' are observed as storms intensify and are robust indicators of strong updrafts and precursors of tornadic activity. Lightning in overshooting convective tops provides another indicator of strong convective surges and a valuable precursor of severity. The lightning observations show the locations of convective cores in storms and can be obtained in real time to monitor and track convective activity, much like meteorological radar. Mapping systems are able to passively detect and track aircraft flying through ice crystal clouds, as well as airborne or ground-based instruments or vehicles carrying active transmitters. Finally, the mapping techniques could readily be adapted to monitor noise and detect faults on power transmission lines.

A Temporal Assessment of Barrier Island Vulnerability to Extreme Wave Events, Virginia Coast Reserve

NASA Astrophysics Data System (ADS)

Oster, D. J.; Moore, L. J.; Doran, K. J.; Stockdon, H. F.

2010-12-01

Barrier island vulnerability to storm-generated waves is directly related to interactions between shoreface morphology and surf-zone dynamics. During storms, the seaward-most dune often limits the landward extent of wave energy; however, if maximum wave run-up exceeds the elevation of the top of the dune, overwash or inundation may occur. The ‘Storm Impact Scale’ presented by Sallenger (2000) classifies barrier beach vulnerability to individual storm events based on the elevation of the frontal dune crest and toe relative to maximum wave run-up. Changes to the dune and beachface can occur over a range of time scales, altering local vulnerability to extreme waves from storms, even as a storm is occurring. As sea level continues to rise, barrier beaches will become increasingly vulnerable to overwash and inundation from a greater number of storms. Our objective is to assess temporal trends in barrier island vulnerability while also exploring island-chain-wide response and recovery from two notably different storm events (Nor’Ida and Hurricane Bonnie) along the undeveloped barrier islands of the Virginia Coast Reserve (VCR). We compare shoreline position and elevations of the frontal dune crest (DHIGH) and dune toe (DLOW) across four lidar data sets collected between 1998-2010. Observed significant wave height and period from the National Data Buoy Center and the Duck, NC Field Research Facility for the time period between 1985 and 2009 are classified to represent one-year, five-year, and ten-year storm events that serve as the basis for comparison of island vulnerability through time to a range of storm severity. Initial results reveal significant spatial and temporal variation in barrier island vulnerability to storms throughout the VCR. Despite the range of variability, all three beach features (i.e., shoreline position, DHIGH and DLOW), have moved landward indicating large-scale, widespread migration, or narrowing, of VCR barrier island landforms over the last 10 years. Potentially evolving long-term trends in island vulnerability appear to be difficult to detect, likely due to the short time window of analysis and the preferential capture of short-term variations as two out of the four lidar data sets were collected immediately following a storm event. Further statistical analysis of changes in frontal dune height (DHIGH) and the distance between the dune toe (DLOW) and shoreline will provide insight into short-term responses to individual storms as well as the potential for future long-term changes in barrier island vulnerability, contributing to a better understanding of barrier island response to rising seas and severe storms.

Ionospheric storms at geophysically-equivalent sites - Part 1: Storm-time patterns for sub-auroral ionospheres

NASA Astrophysics Data System (ADS)

Mendillo, M.; Narvaez, C.

2009-04-01

The systematic study of ionospheric storms has been conducted primarily with groundbased data from the Northern Hemisphere. Significant progress has been made in defining typical morphology patterns at all latitudes; mechanisms have been identified and tested via modeling. At higher mid-latitudes (sites that are typically sub-auroral during non-storm conditions), the processes that change significantly during storms can be of comparable magnitudes, but with different time constants. These include ionospheric plasma dynamics from the penetration of magnetospheric electric fields, enhancements to thermospheric winds due to auroral and Joule heating inputs, disturbance dynamo electrodynamics driven by such winds, and thermospheric composition changes due to the changed circulation patterns. The ~12° tilt of the geomagnetic field axis causes significant longitude effects in all of these processes in the Northern Hemisphere. A complementary series of longitude effects would be expected to occur in the Southern Hemisphere. In this paper we begin a series of studies to investigate the longitudinal-hemispheric similarities and differences in the response of the ionosphere's peak electron density to geomagnetic storms. The ionosonde stations at Wallops Island (VA) and Hobart (Tasmania) have comparable geographic and geomagnetic latitudes for sub-auroral locations, are situated at longitudes close to that of the dipole tilt, and thus serve as our candidate station-pair choice for studies of ionospheric storms at geophysically-comparable locations. They have an excellent record of observations of the ionospheric penetration frequency (foF2) spanning several solar cycles, and thus are suitable for long-term studies. During solar cycle #20 (1964-1976), 206 geomagnetic storms occurred that had Ap≥30 or Kp≥5 for at least one day of the storm. Our analysis of average storm-time perturbations (percent deviations from the monthly means) showed a remarkable agreement at both sites under a variety of conditions. Yet, small differences do appear, and in systematic ways. We attempt to relate these to stresses imposed over a few days of a storm that mimic longer term morphology patterns occurring over seasonal and solar cycle time spans. Storm effects versus season point to possible mechanisms having hemispheric differences (as opposed to simply seasonal differences) in how solar wind energy is transmitted through the magnetosphere into the thermosphere-ionosphere system. Storm effects versus the strength of a geomagnetic storm may, similarly, be related to patterns seen during years of maximum versus minimum solar activity.

Extent and Nature of the Penetration Electric Field in the Northern Hemisphere During the 2013 St. Patrick's Day Storm

NASA Astrophysics Data System (ADS)

Hairston, M. R.; Coley, W. R.; Kunduri, B.; Ruohoniemi, J. M.; Maruyama, N.

2017-12-01

During the 17 March 2013 St. Patrick's Day storm there were four operational DMSP spacecraft (F15 through F18) measuring the ionospheric plasma flows at 840 km. At this time these polar orbiting spacecraft were observing the ionosphere at eight different solar local times, approximately 3.5, 5.4, 5.8, 8.1, 15.5, 17.4, 17.8, and 20.1 hours. Based on the observed zonal flows from each of these local time legs during the period of February through April 2013 we have developed quiet time models of the zonal flows between 10º and 75º geographic latitude. By comparing the observed zonal flows during the storm period with these quiet time models we use the excess difference in the flow to determine the latitudinal extent of the electric penetration field in the northern hemisphere over the course of the storm. By examining the history of the penetration field at different local times we will show the asymmetry in the extent of the field. Additionally, the northern SuperDARN radars observed two SAPS events during this period: one between 5:00 and 10:00 UT on the day prior to the storm and the second between 6:05 and 7:40 UT on the storm day. We will contrast the observed SuperDARN flows during these SAPS events with the quiet time flow models derived from DMSP.

The potential impact of scatterometry on oceanography - A wave forecasting case

NASA Technical Reports Server (NTRS)

Cane, M. A.; Cardone, V. J.

1981-01-01

A series of observing system simulation experiments have been performed in order to assess the potential impact of marine surface wind data on numerical weather prediction. In addition to conventional data, the experiments simulated the time-continuous assimilation of remotely sensed marine surface wind or temperature sounding data. The wind data were fabricated directly for model grid points intercepted by a Seasat-1 scatterometer swath and were assimilated into the lowest active level (945 mb) of the model using a localized successive correction method. It is shown that Seasat wind data can greatly improve numerical weather forecasts due to better definition of specific features. The case of the QE II storm is examined.

Sediment and discharge yields within a minimally disturbed, headwater watershed in North Central Pennsylvania, USA, with an emphasis on Superstorm Sandy

USGS Publications Warehouse

Maloney, Kelly O.; Shull, Dustin R.

2015-01-01

We estimated discharge and suspended sediment (SS) yield in a minimally disturbed watershed in North Central Pennsylvania, USA, and compared a typical storm (September storm, 4.80 cm) to a large storm (Superstorm Sandy, 7.47 cm rainfall). Depending on branch, Sandy contributed 9.7–19.9 times more discharge and 11.5–37.4 times more SS than the September storm. During the September storm, the upper two branches accounted for 60.6% of discharge and 88.8% of SS at Lower Branch; during Sandy these percentages dropped to 36.1% for discharge and 30.1% for SS. The branch with close proximity roads had over two-three times per area SS yield than the branch without such roads. Hysteresis loops showed typical clockwise patterns for the September storm and more complicated patterns for Sandy, reflecting the multipeak event. Estimates of SS and hysteresis in minimally disturbed watersheds provide useful information that can be compared spatially and temporally to facilitate management.

ON THE BRIGHTNESS AND WAITING-TIME DISTRIBUTIONS OF A TYPE III RADIO STORM OBSERVED BY STEREO/WAVES

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

Eastwood, J. P.; Hudson, H. S.; Krucker, S.

2010-01-10

Type III solar radio storms, observed at frequencies below {approx}16 MHz by space-borne radio experiments, correspond to the quasi-continuous, bursty emission of electron beams onto open field lines above active regions. The mechanisms by which a storm can persist in some cases for more than a solar rotation whilst exhibiting considerable radio activity are poorly understood. To address this issue, the statistical properties of a type III storm observed by the STEREO/WAVES radio experiment are presented, examining both the brightness distribution and (for the first time) the waiting-time distribution (WTD). Single power-law behavior is observed in the number distribution asmore » a function of brightness; the power-law index is {approx}2.1 and is largely independent of frequency. The WTD is found to be consistent with a piecewise-constant Poisson process. This indicates that during the storm individual type III bursts occur independently and suggests that the storm dynamics are consistent with avalanche-type behavior in the underlying active region.« less

Mapping geoelectric fields during magnetic storms: Synthetic analysis of empirical United States impedances

NASA Astrophysics Data System (ADS)

Bedrosian, Paul A.; Love, Jeffrey J.

2015-12-01

Empirical impedance tensors obtained from EarthScope magnetotelluric data at sites distributed across the midwestern United States are used to examine the feasibility of mapping magnetic storm induction of geoelectric fields. With these tensors, in order to isolate the effects of Earth conductivity structure, we perform a synthetic analysis—calculating geoelectric field variations induced by a geomagnetic field that is geographically uniform but varying sinusoidally with a chosen set of oscillation frequencies that are characteristic of magnetic storm variations. For north-south oriented geomagnetic oscillations at a period of T0=100 s, induced geoelectric field vectors show substantial geographically distributed differences in amplitude (approximately a factor of 100), direction (up to 130∘), and phase (over a quarter wavelength). These differences are the result of three-dimensional Earth conductivity structure, and they highlight a shortcoming of one-dimensional conductivity models (and other synthetic models not derived from direct geophysical measurement) that are used in the evaluation of storm time geoelectric hazards for the electric power grid industry. A hypothetical extremely intense magnetic storm having 500 nT amplitude at T0=100 s would induce geoelectric fields with an average amplitude across the midwestern United States of about 2.71 V/km, but with a representative site-to-site range of 0.15 V/km to 16.77 V/km. Significant improvement in the evaluation of such hazards will require detailed knowledge of the Earth's interior three-dimensional conductivity structure.

NASA Sees Heavy Rainfall in Tropical Storm Andrea

NASA Image and Video Library

2013-06-06

NASA’s Terra satellite passed over Tropical Storm Andrea on June 5 at 16:25 UTC (12:25 p.m. EDT) and the MODIS instrument captured this visible image of the storm. Andrea’s clouds had already extended over more than half of Florida. Credit: NASA Goddard MODIS Rapid Response Team --- NASA Sees Heavy Rainfall in Tropical Storm Andrea NASA’s TRMM satellite passed over Tropical Storm Andrea right after it was named, while NASA’s Terra satellite captured a visible image of the storm’s reach hours beforehand. TRMM measures rainfall from space and saw that rainfall rates in the southern part of the storm was falling at almost 5 inches per hour. NASA’s Terra satellite passed over Tropical Storm Andrea on June 5 at 16:25 UTC (12:25 p.m. EDT) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument, captured a visible image of the storm. At that time, Andrea’s clouds had already extended over more than half of Florida. At 8 p.m. EDT on Wednesday, June 5, System 91L became the first tropical storm of the Atlantic Ocean hurricane season. Tropical Storm Andrea was centered near 25.5 North and 86.5 West, about 300 miles (485 km) southwest of Tampa, Fla. At the time Andrea intensified into a tropical storm, its maximum sustained winds were near 40 mph (65 kph). Full updates can be found at NASA's Hurricane page: www.nasa.gov/hurricane Rob Gutro NASA’s Goddard Space Flight Center

NASA Sees Heavy Rainfall in Tropical Storm Andrea

NASA Image and Video Library

2017-12-08

This NOAA GOES-East satellite animation shows the development of System 91L into Tropical Storm Andrea over the course of 3 days from June 4 to June 6, just after Andrea was officially designated a tropical storm. Credit: NASA's GOES Project --- NASA Sees Heavy Rainfall in Tropical Storm Andrea NASA’s TRMM satellite passed over Tropical Storm Andrea right after it was named, while NASA’s Terra satellite captured a visible image of the storm’s reach hours beforehand. TRMM measures rainfall from space and saw that rainfall rates in the southern part of the storm was falling at almost 5 inches per hour. NASA’s Terra satellite passed over Tropical Storm Andrea on June 5 at 16:25 UTC (12:25 p.m. EDT) and the Moderate Resolution Imaging Spectroradiometer or MODIS instrument, captured a visible image of the storm. At that time, Andrea’s clouds had already extended over more than half of Florida. At 8 p.m. EDT on Wednesday, June 5, System 91L became the first tropical storm of the Atlantic Ocean hurricane season. Tropical Storm Andrea was centered near 25.5 North and 86.5 West, about 300 miles (485 km) southwest of Tampa, Fla. At the time Andrea intensified into a tropical storm, its maximum sustained winds were near 40 mph (65 kph). Full updates can be found at NASA's Hurricane page: www.nasa.gov/hurricane Rob Gutro NASA’s Goddard Space Flight Center

A Comparison of Cloud-to-Ground Lightning Characteristics and Observations from Multiple Networks and Videos during the 31 May 2013 El Reno, OK Tornadic Supercell Storm

NASA Astrophysics Data System (ADS)

Kuhlman, K. M.; Coy, J.; Seimon, A.

2015-12-01

Cloud-to-ground (CG) lightning flashes recorded by both the National Lightning Detection Network (NLDN) and Earth Networks Total Lightning Network (ENTLN) are compared with three-dimensional lightning mapping observations from the Oklahoma Lightning Mapping Array (OKLMA) and storm chaser video recorded of the 31 May 2013 El Reno tornadic supercell. The El Reno Survey Project (El-Reno-Survey.net) was created to crowd-source the abundance of storm chaser video from this event and provide open-access to the scientific community of the data. An initial comparison of CG lightning flashes captured on these videos with CG data from NLDN revealed a disagreement on the total number of flashes, with NLDN recording many negative CG flashes at lower peak amplitude not apparent in any of the videos. For this study, the area of the comparison was expanded to include the entire storm and data from both the ENTLN and LMA were added to compare the observations from each network in terms of timestamp, location detection, peak current, and polarity of each flash in the period 2230-2330 UTC. An initial comparison of 557 matched NLDN and ENLTN CG flashes, indicated predominately negative polairy CG flashes (58% NLDN/77% ENI) throughout the storm during this period. However, after a 15 kA peak current filter was applied, the NLDN indicated primarily positive polarity (84% +CG) while ENTLN still indicated primarily negative polarity (77% -CG) for the 264 remaining matched flashes. Before the filter was applied, the average distance between the two networks for the same flash was more than 2 km, but improved to approximately 1 km after the 15 kA filter was applied, likely removing some misidentified cloud flashes of uncertain location. This misclassification of IC flashes as CG at low peak current amplitudes for both networks is further evident when compared to video and the OKLMA data. Additionally, the charge analysis of OKLMA flashes revealed the NLDN-determined positive-polarity as correct every time the NLDN and ENTLN disagreed. For the 2013 El Reno supercell storm, there appears to be a major flaw in the ENTLN's ability to determine the polarity of CG flashes despite having roughly similar peak current magnitudes and location for most CG flash occurrences as the NLDN.

Comprehensive Condition Survey and Storm Waves, Circulation, and Sediment Study, Dana Point Harbor, California

DTIC Science & Technology

2014-12-01

waters; 3) west to northwest local sea; 4) prefrontal local sea; 5) tropical storm swell; and 6) extratropical cyclone in the southern hemisphere...14-13 58 Prefrontal local sea The coastal zone within the south Orange County area is vulnerable under extratropical winter storm conditions (a...wave characteristics for severe extratropical storms during the 39 yr time period (1970–2008) are comparable to peak storm wave heights that were

Storm Water Management for Industrial Activities: Developing Pollution Prevention Plans and Best Management Practices

DTIC Science & Technology

1992-09-01

34* Evaluate past spills and leaks "* Identify non-storm water discharges and. illicit connections "* Collect or evaluate storm water quality data...activities or alterations that may be made to reduce the potential that spills will occur or impact storm water quality : "* Develop ways to recycle...be the first time that a spill response plan specifically addresses protection of storm water quality . Past experience has shown that the single most

Energy and Mass Transport of Magnetospheric Plasmas during the November 2003 Magnetic Storm

NASA Technical Reports Server (NTRS)

Fok, Mei-Chging; Moore, Thomas

2008-01-01

Intensive energy and mass transport from the solar wind across the magnetosphere boundary is a trigger of magnetic storms. The storm on 20-21 November 2003 was elicited by a high-speed solar wind and strong southward component of interplanetary magnetic field. This storm attained a minimum Dst of -422 nT. During the storm, some of the solar wind particles enter the magnetosphere and eventually become part of the ring current. At the same time, the fierce solar wind powers strong outflow of H+ and O+ from the ionosphere, as well as from the plasmasphere. We examine the contribution of plasmas from the solar wind, ionosphere and plasmasphere to the storm-time ring current. Our simulation shows, for this particular storm, ionospheric O+ and solar wind ions are the major sources of the ring current particles. The polar wind and plasmaspheric H+ have only minor impacts. In the storm main phase, the strong penetration of solar wind electric field pushes ions from the geosynchronous orbit to L shells of 2 and below. Ring current is greatly intensified during the earthward transport and produces a large magnetic depression in the surface field. When the convection subsides, the deep penetrating ions experience strong charge exchange loss, causing rapid decay of the ring current and fast initial storm recovery. Our simulation reproduces very well the storm development indicated by the Dst index.

Dissemination and implementation of suicide prevention training in one Scottish region

PubMed Central

Gask, Linda; Lever-Green, Gillian; Hays, Rebecca

2008-01-01

Background As part of a national co-ordinated and multifaceted response to the excess suicide rate, the Choose Life initiative, the Highland Choose Life Group launched an ambitious programme of training for National Health Service (NHS), Council and voluntary organisation staff. In this study of the dissemination and implementation of STORM (Skills-based Training On Risk Management), we set out to explore not only the outcomes of training, but key factors involved in the processes of diffusion, dissemination and implementation of the educational intervention. Methods Participants attending STORM training in Highland Region provided by 12 trained facilitators during the period March 2004 to February 2005 were recruited. Quantitative data collection from participants took place at three time points; immediately before training, immediately post-training and six months after training. Semi-structured telephone interviews were carried out with the training facilitators and with a sample of course participants 6 months after they had been trained. We have utilized the conceptual model described by Greenhalgh and colleagues in a Framework analysis of the data, for considering the determinants of diffusion, dissemination and implementation of interventions in health service delivery and organization. Results Some 203 individuals completed a series of questionnaire measures immediately pre (time 1) and immediately post (time 2) training and there were significant improvements in attitudes and confidence of participants. Key factors in the diffusion, dissemination and implementation process were the presence of a champion or local opinion leader who supported and directed the intervention, local adaptation of the materials, commissioning of a group of facilitators who were provided with financial and administrative support, dedicated time to provide the training and regular peer-support. Conclusion Features that contributed to the success of STORM were related to both the context (the multi-dimensional support provided from the host organisation and the favourable policy environment) and the intervention (openness to local adaptation, clinical relevance and utility), and the dynamic interaction between context and the intervention. PMID:19055769

Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

PubMed

Drews, Carl

2013-01-01

The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1.

Convection index as a tool for trend analysis of intense summer storms in Switzerland

NASA Astrophysics Data System (ADS)

Gaal, Ladislav; Molnar, Peter; Szolgay, Jan

2013-04-01

Convective summer thunderstorms are generally responsible for the most devastating floods in urban and small natural catchments. In this study we focus on the identification of the nature and magnitude of changes in the properties of intense summer storms of convective character in Switzerland in the last three decades. The study is based on precipitation records from the SwissMetNet (MeteoSwiss) network at 63 stations that cover altitudes ranging from 200 up to 3300 m a.s.l. over the period 1981-2012 (32 years). Additionally, the same stations also measure the number of lightning strikes within a range of 30 km from each station. In an accompanying contribution we describe the method how intensive summer storms can be reliably selected out of all storms in long and high resolution precipitation time series. On the basis of the statistical distributions and dependence among key storm characteristics at the event scale (total rainfall depth R, storm duration D, and peak intensity I) and using high resolution lightning data as a surrogate we defined a threshold intensity I* that differentiates between the events accompanied with lightning with an acceptably small probability of misclassification. This allowed us to identify intense summer events with convective character as those where I > I* regardless of their duration or total rainfall depth. The current study makes use of the threshold intensity I* for the definition of a seasonal convection index at each station (Llasat, 2001). This index gives us a measure of 'convectiveness', i.e. the total precipitation depth coming from convective storms relative to the total precipitation depth of all summer storms. We computed the convection index at all 63 stations and analyzed the series for trends. We found that the seasonal convection index increases at most of the stations in Switzerland and in approximately 20% of the cases this increase is statistically significant. This is likely a consequence of the fact that the number of summer storms exceeding the threshold I* also shows an increasing tendency with a similar percentage of statistically significant changes. Although our analysis indicates an increasing tendency in the intensity and frequency of summer storms with convective character in Switzerland, it is not yet clear whether these can be traced to causal factors such as atmospheric warming, etc. This remains an open research question.

Storm-driven delivery of sediment to the continental slope: Numerical modeling for the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Harris, C. K.; Kniskern, T. A.; Arango, H.

2016-02-01

The supply of sediment from the continental shelf to deeper waters is of critical importance for building continental margin repositories of sediment, and may also factor into episodic events on the continental slope such as turbidity currents and slope failures. While numerical sediment transport models have been developed for coastal and continental shelf areas, they have not often been used to infer sediment delivery to deeper waters. A three-dimensional coupled hydrodynamic - suspended sediment transport model for the northern Gulf of Mexico has been developed and run to evaluate the types of conditions that are associated with delivery of suspended sediment to the continental slope. Accounting for sediment delivery by riverine plumes and for sediment resuspension by energetic waves and currents, the sediment transport calculations were implemented within the Regional Ocean Modeling System (ROMS). The model domain represents the northern Gulf of Mexico shelf and slope including the Mississippi birdfoot delta and the Mississippi and DeSoto Canyons. To investigate the role of storms in driving down-slope sediment fluxes, model runs that encompassed fall, 2007 through late summer, 2008 the summer and fall of 2008 were analyzed. This time period included several winter storms, and the passage of two hurricanes (Ike and Gustav) over the study area. Preliminary results indicated that sediment delivery to the continental slope was triggered by the passage of these storm events, and focused at certain locations, such as submarine canyons. Additionally, a climatological analysis indicates that storm track influences both the wind-driven currents and wave energy on the shelf, and as such plays an important role in determining which storms trigger delivery of suspended continental shelf sediment to the adjacent slope.

Parameterization of Rocket Dust Storms on Mars in the LMD Martian GCM: Modeling Details and Validation

NASA Astrophysics Data System (ADS)

Wang, Chao; Forget, François; Bertrand, Tanguy; Spiga, Aymeric; Millour, Ehouarn; Navarro, Thomas

2018-04-01

The origin of the detached dust layers observed by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter is still debated. Spiga et al. (2013, https://doi.org/10.1002/jgre.20046) revealed that deep mesoscale convective "rocket dust storms" are likely to play an important role in forming these dust layers. To investigate how the detached dust layers are generated by this mesoscale phenomenon and subsequently evolve at larger scales, a parameterization of rocket dust storms to represent the mesoscale dust convection is designed and included into the Laboratoire de Météorologie Dynamique (LMD) Martian Global Climate Model (GCM). The new parameterization allows dust particles in the GCM to be transported to higher altitudes than in traditional GCMs. Combined with the horizontal transport by large-scale winds, the dust particles spread out and form detached dust layers. During the Martian dusty seasons, the LMD GCM with the new parameterization is able to form detached dust layers. The formation, evolution, and decay of the simulated dust layers are largely in agreement with the Mars Climate Sounder observations. This suggests that mesoscale rocket dust storms are among the key factors to explain the observed detached dust layers on Mars. However, the detached dust layers remain absent in the GCM during the clear seasons, even with the new parameterization. This implies that other relevant atmospheric processes, operating when no dust storms are occurring, are needed to explain the Martian detached dust layers. More observations of local dust storms could improve the ad hoc aspects of this parameterization, such as the trigger and timing of dust injection.

Impact of Atmospheric Aerosols on Solar Photovoltaic Electricity Generation in China

NASA Astrophysics Data System (ADS)

Li, X.; Mauzerall, D. L.; Wagner, F.; Peng, W.; Yang, J.

2016-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

Factors Affecting Source-Water Quality after Disturbance of Forests by Wildfire

NASA Astrophysics Data System (ADS)

Murphy, S. F.; Martin, D. A.; McCleskey, R. B.; Writer, J. H.

2015-12-01

Forests yield high-quality water supplies to communities throughout the world, in part because forest cover reduces flooding and the consequent transport of suspended and dissolved constituents to surface water. Disturbance by wildfire reduces or eliminates forest cover, leaving watersheds susceptible to increased surface runoff during storms and reduced ability to retain contaminants. We assessed water-quality response to hydrologic events for three years after a wildfire in the Fourmile Creek Watershed, near Boulder, Colorado, and found that hydrologic and geochemical responses downstream of a burned area were primarily driven by small, brief convective storms that had relatively high, but not unusual, rainfall intensity. Total suspended sediment, dissolved organic carbon, nitrate, and manganese concentrations were 10-156 times higher downstream of a burned area compared to upstream, and water quality was sufficiently impaired to pose water-treatment concerns. The response in both concentration and yield of water-quality constituents differed depending on source availability and dominant watershed processes controlling the constituent. For example, while all constituent concentrations were highest during storm events, annual sediment yields downstream of the burned area were controlled by storm events and subsequent mobilization, whereas dissolved organic carbon yields were more dependent on spring runoff from upstream areas. The watershed response was affected by a legacy of historical disturbance: the watershed had been recovering from extensive disturbance by mining, railroad and road development, logging, and fires in the late 19th and early 20th centuries, and we observed extensive erosion of mine waste in response to these summer storms. Therefore, both storm characteristics and historical disturbance in a burned watershed must be considered when evaluating the role of wildfire on water quality.

Revised Dst and the epicycles of magnetic disturbance: 1958-2007

USGS Publications Warehouse

Love, J.J.; Gannon, J.L.

2009-01-01

A revised version of the storm-time disturbance index Dst is calculated using hourly-mean magnetic-observatory data from four standard observatories and collected over the years 1958-2007. The calculation algorithm is a revision of that established by Sugiura et al., and which is now used by the Kyoto World Data Center for routine production of Dst. The most important new development is for the removal of solar-quiet variation. This is done through time and frequency-domain band-stop filtering - selectively removing specific Fourier terms approximating stationary periodic variation driven by the Earth's rotation, the Moon's orbit, the Earth's orbit around the Sun, and their mutual coupling. The resulting non-stationary disturbance time series are weighted by observatory-site geomagnetic latitude and then averaged together across longitudes to give what we call Dst5807-4SH. Comparisons are made with the standard Kyoto D st. Various biases, especially for residual solar-quiet variation, are identified in the Kyoto Dst, and occasional storm-time errors in the Kyoto Dst are noted. Using Dst5807-4SH, storms are ranked for maximum storm-time intensity, and we show that storm-occurrence frequency follows a power-law distribution with an exponential cutoff. The epicycles of magnetic disturbance are explored: we (1) map low-latitude local-time disturbance asymmetry, (2) confirm the 27-day storm-recurrence phenomenon using autocorrelation, (3) investigate the coupled semi-annual-diurnal variation of magnetic activity and the proposed explanatory equinoctial and Russell-McPherron hypotheses, and (4) illustrate the well-known solar-cycle modulation of storm-occurrence likelihood. Since Dst5807-4SH is useful for a variety of space physics and solid-Earth applications, it is made freely available to the scientific community.

Monitoring Short-term Cosmic-ray Spectral Variations Using Neutron Monitor Time-delay Measurements

NASA Astrophysics Data System (ADS)

Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.; Kamyan, N.; Muangha, P.; Nutaro, T.; Sumran, S.; Chaiwattana, C.; Gasiprong, N.; Channok, C.; Wuttiya, C.; Rujiwarodom, M.; Tooprakai, P.; Asavapibhop, B.; Bieber, J. W.; Clem, J.; Evenson, P.; Munakata, K.

2016-01-01

Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007-2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed an analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.

MONITORING SHORT-TERM COSMIC-RAY SPECTRAL VARIATIONS USING NEUTRON MONITOR TIME-DELAY MEASUREMENTS

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

Ruffolo, D.; Sáiz, A.; Mangeard, P.-S.

Neutron monitors (NMs) are ground-based detectors of cosmic-ray showers that are widely used for high-precision monitoring of changes in the Galactic cosmic-ray (GCR) flux due to solar storms and solar wind variations. In the present work, we show that a single neutron monitor station can also monitor short-term changes in the GCR spectrum, avoiding the systematic uncertainties in comparing data from different stations, by means of NM time-delay histograms. Using data for 2007–2014 from the Princess Sirindhorn Neutron Monitor, a station at Doi Inthanon, Thailand, with the world’s highest vertical geomagnetic cutoff rigidity of 16.8 GV, we have developed anmore » analysis of time-delay histograms that removes the chance coincidences that can dominate conventional measures of multiplicity. We infer the “leader fraction” L of neutron counts that do not follow a previous neutron count in the same counter from the same atmospheric secondary, which is inversely related to the actual multiplicity and increases for increasing GCR spectral index. After correction for atmospheric pressure and water vapor, we find that L indicates substantial short-term GCR spectral hardening during some but not all Forbush decreases in GCR flux due to solar storms. Such spectral data from Doi Inthanon provide information about cosmic-ray energies beyond the Earth’s maximum geomagnetic cutoff, extending the reach of the worldwide NM network and opening a new avenue in the study of short-term GCR decreases.« less

On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction

DOE PAGES

Olifer, Leonid; Mann, Ian R.; Morley, Steven Karl; ...

2018-04-20

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, themore » moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.« less

On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction

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

Olifer, Leonid; Mann, Ian R.; Morley, Steven Karl

We present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ~0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, themore » moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. Here, we compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.« less

Accepting managed aquifer recharge of urban storm water reuse: The role of policy-related factors

NASA Astrophysics Data System (ADS)

Mankad, Aditi; Walton, Andrea

2015-12-01

A between-groups experimental design examined public acceptance for managed aquifer recharge of storm water for indirect potable and nonpotable reuse; acceptance was based on five policy-related variables (fairness, effectiveness, trust, importance of safety assurances, and importance of communication activities). Results showed that public acceptance (N = 408) for managed aquifer recharge of storm water was higher for nonpotable applications, as was the importance of safety assurances. Analyses of variance also showed that perceptions of fairness and effectiveness were higher for a nonpotable scheme, but not trust. A three-step hierarchical regression (Step 1: age, gender, education, and income; Step 2: type of use; Step 3: fairness, effectiveness, trust, safety assurance, and communication activities) demonstrated that type of storm water use and the policy-related factors accounted for 73% of the variance in acceptance of storm water (R2 = 0.74, adjusted R2 = 0.74, F (10, 397) = 113.919, p < 0.001). Age, type of use, and three of the five policy-related factors were also significant individual predictors of acceptance. The most important predictors were perceptions of trust in water authorities, perceptions of effectiveness, and perceptions of fairness. Interestingly, while safety assurance was important in attitudinal acceptance of managed aquifer recharge based on type of use, safety assurance was not found to be significant predictor of acceptance. This research suggests that policy-makers should look to address matters of greater public importance and drive such as fairness, trust, and effectiveness of storm water programs and advocate these at the forefront of their policies, rather than solely on education campaigns.

Detector signal correction method and system

DOEpatents

Carangelo, Robert M.; Duran, Andrew J.; Kudman, Irwin

1995-07-11

Corrective factors are applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factors may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects.

Detector signal correction method and system

DOEpatents

Carangelo, R.M.; Duran, A.J.; Kudman, I.

1995-07-11

Corrective factors are applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factors may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects. 5 figs.

Radar characteristics of cloud-to-ground lightning producing storms in Florida

NASA Technical Reports Server (NTRS)

Buechler, D. E.; Goodman, S. J.

1991-01-01

The interrelation between cloud-to-ground lightning, convective rainfall, and the environment in Central Florida storms is examined. The rain flux, storm area, and ground discharge rates are computed within the outlined area. Time-height cross sections of maximum dBZ values at each level for two storms are shown. The multicellular nature of these storms is readily apparent. The cloud-to-ground lightning activity occurs mainly where high reflectivity values (30-40 dBZ) extend above 7 km.

Geomagnetic Storm Impact On GPS Code Positioning

NASA Astrophysics Data System (ADS)

Uray, Fırat; Varlık, Abdullah; Kalaycı, İbrahim; Öǧütcü, Sermet

2017-04-01

This paper deals with the geomagnetic storm impact on GPS code processing with using GIPSY/OASIS research software. 12 IGS stations in mid-latitude were chosen to conduct the experiment. These IGS stations were classified as non-cross correlation receiver reporting P1 and P2 (NONCC-P1P2), non-cross correlation receiver reporting C1 and P2 (NONCC-C1P2) and cross-correlation (CC-C1P2) receiver. In order to keep the code processing consistency between the classified receivers, only P2 code observations from the GPS satellites were processed. Four extreme geomagnetic storms October 2003, day of the year (DOY), 29, 30 Halloween Storm, November 2003, DOY 20, November 2004, DOY 08 and four geomagnetic quiet days in 2005 (DOY 92, 98, 99, 100) were chosen for this study. 24-hour rinex data of the IGS stations were processed epoch-by-epoch basis. In this way, receiver clock and Earth Centered Earth Fixed (ECEF) Cartesian Coordinates were solved for a per-epoch basis for each day. IGS combined broadcast ephemeris file (brdc) were used to partly compensate the ionospheric effect on the P2 code observations. There is no tropospheric model was used for the processing. Jet Propulsion Laboratory Application Technology Satellites (JPL ATS) computed coordinates of the stations were taken as true coordinates. The differences of the computed ECEF coordinates and assumed true coordinates were resolved to topocentric coordinates (north, east, up). Root mean square (RMS) errors for each component were calculated for each day. The results show that two-dimensional and vertical accuracy decreases significantly during the geomagnetic storm days comparing with the geomagnetic quiet days. It is observed that vertical accuracy is much more affected than the horizontal accuracy by geomagnetic storm. Up to 50 meters error in vertical component has been observed in geomagnetic storm day. It is also observed that performance of Klobuchar ionospheric correction parameters during geomagnetic storm days cannot guarantee the improving accuracy due to the ionospheric scintillation.

Thermal and Optical Properties of Low-E Storm Windows and Panels

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

Culp, Thomas D.; Widder, Sarah H.; Cort, Katherine A.

Installing low-emissivity (low-E) storm windows and panels over existing windows has been identified as a cost-effective new approach for improving the energy efficiency of existing buildings where window replacement is impractical or too expensive. As such, it is desirable to characterize the key energy performance properties of low-E storm windows and panels when installed over different types of existing primary windows. this paper presents the representative U-factors, solar heat gain coefficients (SGHCs) and visible transmittance properties of the combined assemblies of various storm windows and panel types installed over different primary windows.

Investigation of Media Effects on Removal of Heavy Metals in Bioretention Cells

NASA Astrophysics Data System (ADS)

Gülbaz, Sezar; Melek Kazezyilmaz-Alhan, Cevza; Copty, Nadim K.

2015-04-01

Heavy metals are the most toxic elements at high concentrations, although some of them such as Cu and Zn are essential to plants, humans, and animals within a limited value. However, some heavy metals, such as Pb, have adverse effects even at low concentrations. Therefore, it is known that the toxic metals such as Zn, Cu and Pb in storm water runoff are serious threat for aquatic organisms. It is very important to control and reduce heavy metal concentration in urban storm water runoff. There are several methods to remove the aforementioned toxic metals such as electrolyte extraction, chemical precipitation, ion-exchange, reverse osmosis, membrane filtration, adsorption, cementation, and electrochemical treatment technologies. However, these methods are highly expensive and hard to implement for treatment of big volumes of water such as storm water. For this purpose, Low Impact Development (LID) Best Management Practices (BMPs) have become popular to collect, infiltrate, and treat toxic metals in storm water runoff in recent years. LID-BMP is a land planning method which is used to manage storm water runoff and improve water quality by reducing contaminant in storm water runoff. Bioretention is an example of LID-BMP application of which usage has recently been started in storm water treatment. Researchers have been investigating the advantages of bioretention systems and this study contributes to these research efforts by seeking for the media effects of bioretention on heavy metal removal. For this purpose, batch sorption experiments were performed to determine the distribution coefficients and retardation factor of copper (Cu), lead (Pb), and zinc (Zn) for bioretention media such as mulch, turf, local or vegetative soil, sand and gravel. Furthermore, sorption reaction kinetics of Cu, Pb and Zn are tested in order to assess the sorption equilibrium time of these metals for 5 bioretention media. The results of sorption test show that turf has higher sorption capacity than mulch and local soil for heavy metals used in the experiment. On the other hand, sand and gravel have relatively lower sorption capacities. Linear equilibrium isotherm represents sorption of these metals for all bioretention media. The highest sorption is observed for Pb followed by Cu and Zn for all bioretention media. The time required for reaching equilibrium conditions for bioretention column media is ranged from 1 to 6 hours for each metal investigated.

Tropical Cyclone Diurnal Cycle as Observed by TRMM

NASA Technical Reports Server (NTRS)

Leppert, Kenneth D., II; Cecil, D. J.

2015-01-01

Using infrared satellite data, previous work has shown a consistent diurnal cycle in the pattern of cold cloud tops around mature tropical cyclones. In particular, an increase in the coverage by cold cloud tops often occurs in the inner core of the storm around the time of sunset and subsequently propagates outward to several hundred kilometers over the course of the following day. This consistent cycle may have important implications for structure and intensity changes of tropical cyclones and the forecasting of such changes. Because infrared satellite measurements are primarily sensitive to cloud top, the goal of this study is to use passive and active microwave measurements from the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR), respectively, to examine and better understand the tropical cyclone diurnal cycle throughout a larger depth of the storm's clouds. The National Hurricane Center's best track dataset was used to extract all PR and TMI pixels within 1000 km of each tropical cyclone that occurred in the Atlantic basin between 1998-2011. Then the data was composited according to radius (100-km bins from 0-1000 km) and local standard time (LST; 3-hr bins). Specifically, PR composites involved finding the percentage of pixels with reflectivity greater than or equal to 20 dBZ at various heights (i.e., 2-14 km in increments of 2 km) as a function of radius and time. The 37- and 85- GHz TMI channels are especially sensitive to scattering by precipitation-sized ice in the mid to upper portions of clouds. Hence, the percentage of 37- and 85-GHz polarization corrected temperatures less than various thresholds were calculated using data from all storms as a function of radius and time. For 37 GHz, thresholds of 260 K, 265 K, 270 K, and 275 K were used, and for 85 GHz, thresholds of 200-270 K in increments of 10 K were utilized. Note that convection forced by the interactions of a tropical cyclone with land (e.g., due to frictional convergence) may disrupt the natural convective cycle of a cyclone. Hence, only data pertaining to storms whose centers were greater than 300 km from land were included in the composites. Early results suggest the presence of a diurnal cycle in the PR composites of all Atlantic basin tropical cyclones from a height of 2-12 km from approximately 0-400 km radius, but the cycle is most apparent above 6 km. At a height of 8 km, there is a peak (minimum) in the percentage of PR pixels greater than or equal to 20 dBZ near 0 (21) LST in the inner core with some indication that this signal propagates outward with time. In contrast, the 37- and 85-GHz composites show little indication of a diurnal cycle at any radii, regardless of the threshold used. Ongoing work with this project will involve sub-setting the composites according to storm intensity to see if the diurnal cycle varies with storm strength. Moderate to strong vertical wind shear often leads to asymmetries in tropical cyclone convection and may disrupt the cyclone's natural diurnal cycle. Therefore, wind shear thresholds will be applied to the composites to determine if the diurnal cycle becomes more apparent in a low shear environment. Finally, other work to be completed will involve developing composites for other tropical cyclone basins, including the East Pacific, Northwest Pacific, South Pacific, and Indian Ocean.

Development of a Seasonal Extratropical Cyclone Activity Outlook for the North Pacific, Bering Sea, and Alaskan Regions

NASA Astrophysics Data System (ADS)

Shippee, N. J.; Atkinson, D. E.; Walsh, J. E.; Partain, J.; Gottschalck, J.; Marra, J. J.

2013-12-01

Storm activity (i.e. 'storminess') and associated forecasting skill in the North Pacific, Bering Sea, and Alaska is relatively well understood on a daily to weekly scale, however, two important elements are missing from current capacity. First, there is no way to predict storm activity at the monthly to seasonal time frame. Second, storm activity is characterized in terms that best serve weather specialists, and which are often not very informative for different sectors of the public. Increasing the utility of forecasts for end users requires consultation with these groups, and can include expressing storm activity in terms of, for example, strong-wind return intervals or ship hull strength. These types of forecasts can provide valuable information for use in community planning, resource allocation, or potential risk assessment. A preliminary study of seasonal storminess predictability in the North Pacific and Alaska regions has shown that a key factor related to the annual variation of seasonal storminess is the strength of the Aleutian Low as measured using indices such as the North Pacific Index (NPI) or Aleutian Low Pressure Index (ALPI). Use of Empirical Orthogonal Function (EOF) analysis to identify patterns in storminess variability indicates that the primary mode of annual variation is found to be best explained by the variation in the strength of the Aleutian Low. NPI and the first component of storm activity for the entire region are found to be are highly correlated (R = 0.83). This result is supported by the works of others such as Rodionov et al. (2007), who note the impact of the strength of the Aleutian Low on storm track and speed. Additionally, the phase of the Pacific Decadal Oscillation (PDO), along with NPI, have been shown to be highly correlated with annual variance in the seasonal storminess for the North Pacific and Alaska. Additional skill has been identified when the phase of the Pacific Decadal Oscillation (PDO) is explicitly considered along with that of the NPI. For example, where the December through March NPI anomaly is negative, indicating a strong Aleutian Low, and PDO anomaly is positive, storminess is increased in the Aleutians and the Bering Sea and storms more rapidly exit the Gulf of Alaska. In similar fashion, when the phases of the NPI and PDO anomaly are switched, the storminess increases into the Gulf of Alaska with slower moving storms and longer residence time in the Gulf of Alaska. Methods used to develop the seasonal outlooks and the overall results of the will be overviewed in this presentation.

The eSurge-Venice project: altimeter and scatterometer satellite data to improve the storm surge forecasting in the city of Venice

NASA Astrophysics Data System (ADS)

Zecchetto, Stefano; De Biasio, Francesco; Umgiesser, Georg; Bajo, Marco; Vignudelli, Stefano; Papa, Alvise; Donlon, Craig; Bellafiore, Debora

2013-04-01

On the framework of the Data User Element (DUE) program, the European Space Agency is funding a project to use altimeter Total Water Level Envelope (TWLE) and scatterometer wind data to improve the storm surge forecasting in the Adriatic Sea and in the city of Venice. The project will: a) Select a number of Storm Surge Events occurred in the Venice lagoon in the period 1999-present day b) Provide the available satellite Earth Observation (EO) data related to the Storm Surge Events, mainly satellite winds and altimeter data, as well as all the available in-situ data and model forecasts c) Provide a demonstration Near Real Time service of EO data products and services in support of operational and experimental forecasting and warning services d) Run a number of re-analysis cases, both for historical and contemporary storm surge events, to demonstrate the usefulness of EO data The re-analysis experiments, based on hindcasts performed by the finite element 2-D oceanographic model SHYFEM (https://sites.google.com/site/shyfem/), will 1. use different forcing wind fields (calibrated and not calibrated with satellite wind data) 2. use Storm Surge Model initial conditions determined from altimeter TWLE data. The experience gained working with scatterometer and Numerical Weather Prediction (NWP) winds in the Adriatic Sea tells us that the bias NWP-Scatt wind is negative and spatially and temporally not uniform. In particular, a well established point is that the bias is higher close to coasts then offshore. Therefore, NWP wind speed calibration will be carried out on each single grid point in the Adriatic Sea domain over the period of a Storm Surge Event, taking into account of existing published methods. Point #2 considers two different methodologies to be used in re-analysis tests. One is based on the use of the TWLE values from altimeter data in the Storm Surge Model (SSM), applying data assimilation methodologies and trying to optimize the initial conditions of the simulation.The second possibility is an indirect exploitation of the TWLE data from altimeter in an ensemble-like framework, obtained by slight variations of the external forcing. In this case the wind data from NWP models will be weakly altered (shifted in phase), the drag coefficient will be modified, and the initial condition of the model slightly shifted in time to account for the uncertainty of these factors. This contribution will illustrate the geophysical context of work and outline the results.

Depth-area-duration characteristics of storm rainfall in Texas using Multi-Sensor Precipitation Estimates

NASA Astrophysics Data System (ADS)

McEnery, J. A.; Jitkajornwanich, K.

2012-12-01

This presentation will describe the methodology and overall system development by which a benchmark dataset of precipitation information has been used to characterize the depth-area-duration relations in heavy rain storms occurring over regions of Texas. Over the past two years project investigators along with the National Weather Service (NWS) West Gulf River Forecast Center (WGRFC) have developed and operated a gateway data system to ingest, store, and disseminate NWS multi-sensor precipitation estimates (MPE). As a pilot project of the Integrated Water Resources Science and Services (IWRSS) initiative, this testbed uses a Standard Query Language (SQL) server to maintain a full archive of current and historic MPE values within the WGRFC service area. These time series values are made available for public access as web services in the standard WaterML format. Having this volume of information maintained in a comprehensive database now allows the use of relational analysis capabilities within SQL to leverage these multi-sensor precipitation values and produce a valuable derivative product. The area of focus for this study is North Texas and will utilize values that originated from the West Gulf River Forecast Center (WGRFC); one of three River Forecast Centers currently represented in the holdings of this data system. Over the past two decades, NEXRAD radar has dramatically improved the ability to record rainfall. The resulting hourly MPE values, distributed over an approximate 4 km by 4 km grid, are considered by the NWS to be the "best estimate" of rainfall. The data server provides an accepted standard interface for internet access to the largest time-series dataset of NEXRAD based MPE values ever assembled. An automated script has been written to search and extract storms over the 18 year period of record from the contents of this massive historical precipitation database. Not only can it extract site-specific storms, but also duration-specific storms and storms separated by user defined inter-event periods. A separate storm database has been created to store the selected output. By storing output within tables in a separate database, we can make use of powerful SQL capabilities to perform flexible pattern analysis. Previous efforts have made use of historic data from limited clusters of irregularly spaced physical gauges. Spatial extent of the observational network has been a limiting factor. The relatively dense distribution of MPE provides a virtual mesh of observations stretched over the landscape. This work combines a unique hydrologic data resource with programming and database analysis to characterize storm depth-area-duration relationships.

Accelerating Dust Storm Simulation by Balancing Task Allocation in Parallel Computing Environment

NASA Astrophysics Data System (ADS)

Gui, Z.; Yang, C.; XIA, J.; Huang, Q.; YU, M.

2013-12-01

Dust storm has serious negative impacts on environment, human health, and assets. The continuing global climate change has increased the frequency and intensity of dust storm in the past decades. To better understand and predict the distribution, intensity and structure of dust storm, a series of dust storm models have been developed, such as Dust Regional Atmospheric Model (DREAM), the NMM meteorological module (NMM-dust) and Chinese Unified Atmospheric Chemistry Environment for Dust (CUACE/Dust). The developments and applications of these models have contributed significantly to both scientific research and our daily life. However, dust storm simulation is a data and computing intensive process. Normally, a simulation for a single dust storm event may take several days or hours to run. It seriously impacts the timeliness of prediction and potential applications. To speed up the process, high performance computing is widely adopted. By partitioning a large study area into small subdomains according to their geographic location and executing them on different computing nodes in a parallel fashion, the computing performance can be significantly improved. Since spatiotemporal correlations exist in the geophysical process of dust storm simulation, each subdomain allocated to a node need to communicate with other geographically adjacent subdomains to exchange data. Inappropriate allocations may introduce imbalance task loads and unnecessary communications among computing nodes. Therefore, task allocation method is the key factor, which may impact the feasibility of the paralleling. The allocation algorithm needs to carefully leverage the computing cost and communication cost for each computing node to minimize total execution time and reduce overall communication cost for the entire system. This presentation introduces two algorithms for such allocation and compares them with evenly distributed allocation method. Specifically, 1) In order to get optimized solutions, a quadratic programming based modeling method is proposed. This algorithm performs well with small amount of computing tasks. However, its efficiency decreases significantly as the subdomain number and computing node number increase. 2) To compensate performance decreasing for large scale tasks, a K-Means clustering based algorithm is introduced. Instead of dedicating to get optimized solutions, this method can get relatively good feasible solutions within acceptable time. However, it may introduce imbalance communication for nodes or node-isolated subdomains. This research shows both two algorithms have their own strength and weakness for task allocation. A combination of the two algorithms is under study to obtain a better performance. Keywords: Scheduling; Parallel Computing; Load Balance; Optimization; Cost Model

Watershed and land use-based sources of trace metals in urban storm water.

PubMed

Tiefenthaler, Liesl L; Stein, Eric D; Schiff, Kenneth C

2008-02-01

Trace metal contributions in urban storm water are of concern to environmental managers because of their potential impacts on ambient receiving waters. The mechanisms and processes that influence temporal and spatial patterns of trace metal loading in urban storm water, however, are not well understood. The goals of the present study were to quantify trace metal event mean concentration (EMC), flux, and mass loading associated with storm water runoff from representative land uses; to compare EMC, flux, and mass loading associated with storm water runoff from urban (developed) and nonurban (undeveloped) watersheds; and to investigate within-storm and within-season factors that affect trace metal concentration and flux. To achieve these goals, trace metal concentrations were measured in 315 samples over 11 storm events in five southern California, USA, watersheds representing eight different land use types during the 2000 through 2005 storm seasons. In addition, 377 runoff samples were collected from 12 mass emission sites (end of watershed) during 15 different storm events. Mean flux at land use sites ranged from 24 to 1,238, 0.1 to 1,272, and 6 to 33,189 g/km(2) for total copper, total lead, and total zinc, respectively. Storm water runoff from industrial land use sites contained higher EMCs and generated greater flux of trace metals than other land use types. For all storms sampled, the highest metal concentrations occurred during the early phases of storm water runoff, with peak concentrations usually preceding peak flow. Early season storms produced significantly higher metal flux compared with late season storms at both mass emission and land use sites.

The evolution of the storm-time ring current in response to different characteristics of the plasma source

NASA Astrophysics Data System (ADS)

Lemon, C.; Chen, M.; O'Brien, T. P.; Toffoletto, F.; Sazykin, S.; Wolf, R.; Kumar, V.

2006-12-01

We present simulation results of the Rice Convection Model-Equilibrium (RCM-E) that test and compare the effect on the storm time ring current of varying the plasma sheet source population characteristics at 6.6 Re during magnetic storms. Previous work has shown that direct injection of ionospheric plasma into the ring current is not a significant source of ring current plasma, suggesting that the plasma sheet is the only source. However, storm time processes in the plasma sheet and inner magnetosphere are very complex, due in large part to the feedback interactions between the plasma distribution, magnetic field, and electric field. We are particularly interested in understanding the role of the plasma sheet entropy parameter (PV^{5/3}, where V=\\int ds/B) in determining the strength and distribution of the ring current in both the main and recovery phases of a storm. Plasma temperature and density can be measured from geosynchrorous orbiting satellites, and these are often used to provide boundary conditions for ring current simulations. However, magnetic field measurements in this region are less commonly available, and there is a relatively poor understanding of the interplay between the plasma and the magnetic field during magnetic storms. The entropy parameter is a quantity that incorporates both the plasma and the magnetic field, and understanding its role in the ring current injection and recovery is essential to describing the processes that are occuring during magnetic storms. The RCM-E includes the physics of feedback between the plasma and both the electric and magnetic fields, and is therefore a valuable tool for understanding these complex storm-time processes. By contrasting the effects of different plasma boundary conditions at geosynchronous orbit, we shed light on the physical processes involved in ring current injection and recovery.

Forecast of geomagnetic storms using CME parameters and the WSA-ENLIL model

NASA Astrophysics Data System (ADS)

Moon, Y.; Lee, J.; Jang, S.; Na, H.; Lee, J.

2013-12-01

Intense geomagnetic storms are caused by coronal mass ejections (CMEs) from the Sun and their forecast is quite important in protecting space- and ground-based technological systems. The onset and strength of geomagnetic storms depend on the kinematic and magnetic properties of CMEs. Current forecast techniques mostly use solar wind in-situ measurements that provide only a short lead time. On the other hand, techniques using CME observations near the Sun have the potential to provide 1-3 days of lead time before the storm occurs. Therefore, one of the challenging issues is to forecast interplanetary magnetic field (IMF) southward components and hence geomagnetic storm strength with a lead-time on the order of 1-3 days. We are going to answer the following three questions: (1) when does a CME arrive at the Earth? (2) what is the probability that a CME can induce a geomagnetic storm? and (3) how strong is the storm? To address the first question, we forecast the arrival time and other physical parameters of CMEs at the Earth using the WSA-ENLIL model with three CME cone types. The second question is answered by examining the geoeffective and non-geoeffective CMEs depending on CME observations (speed, source location, earthward direction, magnetic field orientation, and cone-model output). The third question is addressed by examining the relationship between CME parameters and geomagnetic indices (or IMF southward component). The forecast method will be developed with a three-stage approach, which will make a prediction within four hours after the solar coronagraph data become available. We expect that this study will enable us to forecast the onset and strength of a geomagnetic storm a few days in advance using only CME parameters and the physics-based models.

A new approach for the assessment of temporal clustering of extratropical wind storms

NASA Astrophysics Data System (ADS)

Schuster, Mareike; Eddounia, Fadoua; Kuhnel, Ivan; Ulbrich, Uwe

2017-04-01

A widely-used methodology to assess the clustering of storms in a region is based on dispersion statistics of a simple homogeneous Poisson process. This clustering measure is determined by the ratio of the variance and the mean of the local storm statistics per grid point. Resulting values larger than 1, i.e. when the variance is larger than the mean, indicate clustering; while values lower than 1 indicate a sequencing of storms that is more regular than a random process. However, a disadvantage of this methodology is that the characteristics are valid for a pre-defined climatological time period, and it is not possible to identify a temporal variability of clustering. Also, the absolute value of the dispersion statistics is not particularly intuitive. We have developed an approach to describe temporal clustering of storms which offers a more intuitive comprehension, and at the same time allows to assess temporal variations. The approach is based on the local distribution of waiting times between the occurrence of two individual storm events, the former being computed through the post-processing of individual windstorm tracks which in turn are obtained by an objective tracking algorithm. Based on this distribution a threshold can be set, either by the waiting time expected from a random process or by a quantile of the observed distribution. Thus, it can be determined if two consecutive wind storm events count as part of a (temporal) cluster. We analyze extratropical wind storms in a reanalysis dataset and compare the results of the traditional clustering measure with our new methodology. We assess what range of clustering events (in terms of duration and frequency) is covered and identify if the historically known clustered seasons are detectable by the new clustering measure in the reanalysis.

Long-Range Lightning Products for Short Term Forecasting of Tropical Cyclogenesis

NASA Astrophysics Data System (ADS)

Businger, S.; Pessi, A.; Robinson, T.; Stolz, D.

2010-12-01

This paper will describe innovative graphical products derived in real time from long-range lightning data. The products have been designed to aid in short-term forecasting of tropical cyclone development for the Tropical Cyclone Structure Experiment 2010 (TCS10) held over the western Pacific Ocean from 17 August to 17 October 2010 and are available online at http://www.soest.hawaii.edu/cgi-bin/pacnet/tcs10.pl. The long-range lightning data are from Vaisala’s Global Lightning Data 360 (GLD360) network and include time, location, current strength, polarity, and data quality indication. The products currently provided in real time include i. Infrared satellite imagery overlaid with lighting flash locations, with color indication of current strength and polarity (shades of blue for negative to ground and red for positive to ground). ii. A 15x15 degree storm-centered tile of IR imagery overlaid with lightning data as in i). iii. A pseudo reflectivity product showing estimates of radar reflectivity based on lightning rate - rain rate conversion derived from TRMM and PacNet data. iv. A lightning history product that plots each hour of lightning flash locations in a different color for a 12-hour period. v. Graphs of lightning counts within 50 or 300 km radius, respectively, of the storm center vs storm central sea-level pressure. vi. A 2-D graphic showing storm core lightning density along the storm track. The first three products above can be looped to gain a better understanding of the evolution of the lightning and storm structure. Examples of the graphics and their utility will be demonstrated and discussed. Histogram of lightning counts within 50 km of the storm center and graph of storm central pressure as a function of time.

Storm and Clouds

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

Yesterday's storm front was moving westward, today's moves eastward. Note the thick cloud cover and beautifully delineated cloud tops.

Image information: VIS instrument. Latitude 72.1, Longitude 308.3 East (51.7 West). 40 meter/pixel resolution.

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

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

Mature thunderstorm cloud top structure - Three-dimensional numerical simulation versus satellite observations

NASA Technical Reports Server (NTRS)

Schlesinger, R. E.

1982-01-01

Preliminary results of four runs with a three-dimensional model of the effects of vertical wind shear on cloud top height/temperature structure and the internal properties of isolate midlatitude thunderstorms are reported. The model is being developed as an aid to analyses of GEO remote sensing satellite data. The grid is a 27 x 27 x 20 mesh with 2 km horizontal resolution and 0.9 vertical resolution. The total grid is 54 km on a side and 18 km deep. A second-order Crowley scheme for advecting momentum is extended with a third-order correction for spatial truncation error, and the earth-relative horizontal surface wind components are decreased to 50 percent of their values at 0.45 km. A temperature increase with height is included, together with an initial impulse consisting of a nonrotating cylindrical weak buoyant updraft 10 km in radius. The results of the runs are discussed in terms of the time variation of the vertical velocity extrema, the effects of strong and weak shear on a storm, the cloud top height, the Lagrangian dynamics of a thermal couplet, and data from a real storm.

Hurricane & Tropical Storm Impacts over the South Florida Metropolitan Area: Mortality & Government

NASA Astrophysics Data System (ADS)

Colon Pagan, I. C.

2007-12-01

Since 1985, the South Florida Metropolitan area (SFMA), which covers the counties of Miami-Dade, Broward, and Palm Beach, has been directly affected by 9 tropical cyclones: four tropical storms and 5 hurricanes. This continuous hurricane and tropical storm activity has awakened the conscience of the communities, government, and private sector, about the social vulnerability, in terms of age, gender, ethnicity, and others. Several factors have also been significant enough to affect the vulnerability of the South Florida Metropolitan area, like its geographic location which is at the western part of the Atlantic hurricane track, with a surface area of 6,137 square miles, and elevation of 15 feet. And second, from the 2006 Census estimate, this metropolitan area is the 7th most populous area in the United States supporting almost 1,571 individuals per square mile. Mortality levels due to hurricanes and tropical storms have fluctuated over the last 21 years without any signal of a complete reduction, a phenomenon that can be related to both physical characteristics of the storms and government actions. The average annual death count remains almost the same from 4.10 between 1985 and 1995 to 4 from 1996 to 2006. However, the probability of occurrence of a direct impact of an atmospheric disturbance has increase from 0.3 to 0.6, with an average of three hurricane or tropical storm direct impacts for every five. This analysis suggests an increasing problem with regard to atmospheric disturbances-related deaths in the South Florida Metropolitan area. In other words, despite substantial increases in population during the last 21 years, the number of tropical cyclone-related deaths is not declining; it's just being segregated among more storms. Gaps between each impact can be related to mortality levels. When that time increases in five years or more, such as Bob and Andrew or Irene and Katrina, or decreases in weeks or months, such as Harvey and Irene or Katrina and Wilma, mortality also increases. A relief is also remarkable when that time is between one and four years, which might be related to better government actions during a certain period after a strong hurricane impact. Results reflect a lack of focus on hurricane and tropical storm related themes, while a decrease in funding can be the consequence of less interest and much more attention on less probable hazards with a long term recovery period. Even though the government has an important role in hurricanes and tropical storms mitigation, some of the main ideas to decrease mortality are focused in networking between private and public sector and the understanding of self-vulnerability of each individual.

Hurricane Harvey rapid response: observations of infragravity wave dynamics and morphological change during inundation of a barrier island cut

NASA Astrophysics Data System (ADS)

Anarde, K.; Figlus, J.; Dellapenna, T. M.; Bedient, P. B.

2017-12-01

Prior to landfall of Hurricane Harvey on August 25, 2017, instrumentation was deployed on the seaward and landward sides of a barrier island on the central Texas Gulf Coast to collect in-situ hydrodynamic measurements during storm impact. High-resolution devices capable of withstanding extreme conditions included inexpensive pressure transducers and tilt current meters mounted within and atop (respectively) shallow monitoring wells. In order to link measurements of storm hydrodynamics with the morphological evolution of the barrier, pre- and post-storm digital elevation models were generated using a combination of unmanned aerial imagery, LiDAR, and real-time kinematic GPS. Push-cores were collected and analyzed for grain size and sedimentary structure to relate hydrodynamic observations with the local character of storm-generated deposits. Observations show that at Hog Island, located approximately 160 miles northeast of Harvey's landfall location, storm surge inundated an inactive storm channel. Infragravity waves (0.003 - 0.05 Hz) dominated the water motion onshore of the berm crest over a 24-hour period proximate to storm landfall. Over this time, approximately 50 cm of sediment accreted vertically atop the instrument located in the backshore. Storm deposits at this location contained sub-parallel alternating laminae of quartz and heavy mineral-enriched sand. While onshore progression of infragravity waves into the back-barrier was observed over several hours prior to storm landfall, storm deposits in the back-barrier lack the characteristic laminae preserved in the backshore. These field measurements will ultimately be used to constrain and validate numerical modeling schemes that explore morphodynamic conditions of barriers in response to extreme storms (e.g., XBeach, CSHORE). This study provides a unique data set linking extreme storm hydrodynamics with geomorphic changes during a relatively low surge, but highly dissipative wave event.

Quantitative Simulation of QARBM Challenge Events During Radiation Belt Enhancements

NASA Astrophysics Data System (ADS)

Li, W.; Ma, Q.; Thorne, R. M.; Bortnik, J.; Chu, X.

2017-12-01

Various physical processes are known to affect energetic electron dynamics in the Earth's radiation belts, but their quantitative effects at different times and locations in space need further investigation. This presentation focuses on discussing the quantitative roles of various physical processes that affect Earth's radiation belt electron dynamics during radiation belt enhancement challenge events (storm-time vs. non-storm-time) selected by the GEM Quantitative Assessment of Radiation Belt Modeling (QARBM) focus group. We construct realistic global distributions of whistler-mode chorus waves, adopt various versions of radial diffusion models (statistical and event-specific), and use the global evolution of other potentially important plasma waves including plasmaspheric hiss, magnetosonic waves, and electromagnetic ion cyclotron waves from all available multi-satellite measurements. These state-of-the-art wave properties and distributions on a global scale are used to calculate diffusion coefficients, that are then adopted as inputs to simulate the dynamical electron evolution using a 3D diffusion simulation during the storm-time and the non-storm-time acceleration events respectively. We explore the similarities and differences in the dominant physical processes that cause radiation belt electron dynamics during the storm-time and non-storm-time acceleration events. The quantitative role of each physical process is determined by comparing against the Van Allen Probes electron observations at different energies, pitch angles, and L-MLT regions. This quantitative comparison further indicates instances when quasilinear theory is sufficient to explain the observed electron dynamics or when nonlinear interaction is required to reproduce the energetic electron evolution observed by the Van Allen Probes.

Thermosphere Global Time Response to Geomagnetic Storms Caused by Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Oliveira, D. M.; Zesta, E.; Schuck, P. W.; Sutton, E. K.

2017-10-01

We investigate, for the first time with a spatial superposed epoch analysis study, the thermosphere global time response to 159 geomagnetic storms caused by coronal mass ejections (CMEs) observed in the solar wind at Earth's orbit during the period of September 2001 to September 2011. The thermosphere neutral mass density is obtained from the CHAMP (CHAllenge Mini-Satellite Payload) and GRACE (Gravity Recovery Climate Experiment) spacecraft. All density measurements are intercalibrated against densities computed by the Jacchia-Bowman 2008 empirical model under the regime of very low geomagnetic activity. We explore both the effects of the pre-CME shock impact on the thermosphere and of the storm main phase onset by taking their times of occurrence as zero epoch times (CME impact and interplanetary magnetic field Bz southward turning) for each storm. We find that the shock impact produces quick and transient responses at the two high-latitude regions with minimal propagation toward lower latitudes. In both cases, thermosphere is heated in very high latitude regions within several minutes. The Bz southward turning of the storm onset has a fast heating manifestation at the two high-latitude regions, and it takes approximately 3 h for that heating to propagate down to equatorial latitudes and to globalize in the thermosphere. This heating propagation is presumably accomplished, at least in part, with traveling atmospheric disturbances and complex meridional wind structures. Current models use longer lag times in computing thermosphere density dynamics during storms. Our results suggest that the thermosphere response time scales are shorter and should be accordingly adjusted in thermospheric empirical models.

Relativistic electron precipitation during geomagnetic storm time in the years 2006-2010

NASA Astrophysics Data System (ADS)

Glesnes Ødegaard, Linn-Kristine; Nesse Tyssøy, Hilde; Sandanger, Marit irene; Stadsnes, Johan; Søraas, Finn

2015-04-01

The processes leading to acceleration or loss of relativistic electrons in the magnetosphere during geomagnetic storm time have yet to be fully understood, and whether a geomagnetic storm will lead to enhanced or depleted fluxes of relativistic electrons can not be known in advance. Relativistic Electron Precipitation (REP) can penetrate deep into the atmosphere and influence composition and dynamics. To study the effect of REP upon the atmosphere, the energy and intensity of the electrons need to be accurately represented. We use satellite measurements of electrons with energies E>300 keV and E>1000 keV to study the behaviour of these electron populations during geomagnetic storms. We use the MEPED detectors on board the POES satellites NOAA-17, NOAA-18, MetOp-02 and NOAA-19, where the vertical telescope measures precipitated flux, and the horizontal telescope trapped flux at satellite altitude (ca 850 km). Using a newly developed technique, we can derive the flux of electrons depositing their energy in the atmosphere from the pair of detectors on each satellite. 75 isolated storms were identified in the period 2006-2010. The storms include both typical CME driven storms, and weak long duration storms driven by CIRs. Each storm was divided into pre-storm phase, main phase and recovery phase, and the flux of relativistic electrons was monitored through the storms. By combining the measurements from several satellites, we obtain a close to global view of the relativistic electron fluxes, enabling us to study the relationship between the REP and different geomagnetic indices and solar wind drivers.

A correlative comparison of the ring current and auroral electrojects usig geomagnetic indices

NASA Technical Reports Server (NTRS)

Cade, W. B., III; Sojka, J. J.; Zhu, L.

1995-01-01

From a study of the 21 largest geomagnetic storms during solar cycle 21, a strong correlation is established between the ring current index Dst and the time-weighted accumulation of the 1-hour auroral electrojets indices, AE and AL. The time-weighted accumulation corresponds to convolution of the auroral electrojet indices with an exponential weighting function with an e-folding time of 9.4 hours. The weighted indices AE(sub w) and AL(sub w) have correltation coefficients against Dst ranging between 0.8 and 0.95 for 20 of the 21 storms. Correlation over the entire solar cycle 21 database is also strong but not as strong as for an individual storm. A set of simple Dst prediction functions provide a first approximation of the inferred dependence, but the specific functional relationship of Dst (AL(sub w)) or Dst (AL(sub w)) varies from one storm to the next in a systematic way. This variation reveals a missing parametric dependence in the transfer function. However, our results indicate that auroral electroject indices are potentially useful for predicting storm time enhancements of ring current intensity with a few hours lead time.

Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO2 atmosphere

Treesearch

Heather R. McCarthy; Ram Oren; Hyun-Seok Kim; Kurt H. Johnsen; Chris Maier; Seth G. Pritchard; Michael A. Davis

2006-01-01

Ice storms are disturbance events with potential impacts on carbon sequestration. Common forest management practices, such as fertilization and thinning, can change wood and stand properties and thus may change vulnerability to ice storm damage. At the same time, increasing atmospheric CO2 levels may also influence ice storm vulnerability. Here...

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups.

PubMed

Jin, Xue; Shi, Xiaoxia; Gao, Jintian; Xu, Tongbin; Yin, Kedong

2018-03-27

Storm surge has become an important factor restricting the economic and social development of China's coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc.), storm surge disaster is divided based on eight kinds of storm surge disaster grade division methods combined with storm surge water, hypervigilance tide level, and disaster loss. The storm surge disaster loss measurement model groups consist of eight equations, and six major modules are constructed: storm surge disaster in agricultural loss, fishery loss, human resource loss, engineering facility loss, living facility loss, and direct economic loss. Finally, the support vector machine (SVM) model is used to evaluate the loss and the intra-sample prediction. It is indicated that the equations of the model groups can reflect in detail the relationship between the damage of storm surges and other related variables. Based on a comparison of the original value and the predicted value error, the model groups pass the test, providing scientific support and a decision basis for the early layout of disaster prevention and mitigation.

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups

PubMed Central

Shi, Xiaoxia; Xu, Tongbin; Yin, Kedong

2018-01-01

Storm surge has become an important factor restricting the economic and social development of China’s coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc.), storm surge disaster is divided based on eight kinds of storm surge disaster grade division methods combined with storm surge water, hypervigilance tide level, and disaster loss. The storm surge disaster loss measurement model groups consist of eight equations, and six major modules are constructed: storm surge disaster in agricultural loss, fishery loss, human resource loss, engineering facility loss, living facility loss, and direct economic loss. Finally, the support vector machine (SVM) model is used to evaluate the loss and the intra-sample prediction. It is indicated that the equations of the model groups can reflect in detail the relationship between the damage of storm surges and other related variables. Based on a comparison of the original value and the predicted value error, the model groups pass the test, providing scientific support and a decision basis for the early layout of disaster prevention and mitigation. PMID:29584628

Positive and negative ionospheric responses to the March 2015 geomagnetic storm from BDS observations

NASA Astrophysics Data System (ADS)

Jin, Shuanggen; Jin, Rui; Kutoglu, H.

2017-06-01

The most intense geomagnetic storm in solar cycle 24 occurred on March 17, 2015, and the detailed ionospheric storm morphologies are difficultly obtained from traditional observations. In this paper, the Geostationary Earth Orbit (GEO) observations of BeiDou Navigation Satellite System (BDS) are for the first time used to investigate the ionospheric responses to the geomagnetic storm. Using BDS GEO and GIMs TEC series, negative and positive responses to the March 2015 storm are found at local and global scales. During the main phase, positive ionospheric storm is the main response to the geomagnetic storm, while in the recovery phase, negative phases are pronounced at all latitudes. Maximum amplitudes of negative and positive phases appear in the afternoon and post-dusk sectors during both main and recovery phases. Furthermore, dual-peak positive phases in main phase and repeated negative phase during the recovery are found from BDS GEO observations. The geomagnetic latitudes corresponding to the maximum disturbances during the main and recovery phases show large differences, but they are quasi-symmetrical between southern and northern hemispheres. No clear zonal propagation of traveling ionospheric disturbances is detected in the GNSS TEC disturbances at high and low latitudes. The thermospheric composition variations could be the dominant source of the observed ionospheric storm effect from GUVI [O]/[N2] ratio data as well as storm-time electric fields. Our study demonstrates that the BDS (especially the GEO) observations are an important data source to observe ionospheric responses to the geomagnetic storm.

Long Duration Enhancement And Depletion Observed In The Topside Ionospheric Electron Content During The March 2015 Strong Storm

NASA Astrophysics Data System (ADS)

Zhong, J.; Wang, W.; Yue, X.; Burns, A. G.; Dou, X.; Lei, J.

2015-12-01

Up-looking total electron content (TEC) measurements from multiple low Earth orbit (LEO) satellites have been utilized to study the topside ionospheric response to the 17 March 2015 great storm. The combined up-looking TEC observations from these LEO satellites are valuable in addressing the local time and altitudinal dependences of the topside ionospheric response to geomagnetic storms from a global perspective, especially over the southern hemisphere and oceans. In the evening sector, the up-looking TEC showed an obvious long-duration of positive storm effect during the main phase and a long duration of negative storm effect during the recovery phase of this storm. The increases of the topside TEC during the main phase were symmetric with respect to the magnetic equator, which was probably associated with penetration electric fields. Additionally, the up-looking TEC from different orbital altitudes suggested that the negative storm effect at higher altitudes was stronger in the evening sector. In the morning sector, the up-looking TEC also showed increases at low and middle latitudes during the storm main phase. Obvious TEC enhancement can be also seen over the Pacific Ocean in the topside ionosphere during the storm recovery phase. These results imply that the topside ionospheric responses significantly depend on local time. Thus, the LEO-based up-looking TEC provides an important database to study the possible physical mechanisms of the topside ionospheric response to storms.

Variations in Heavy Metals Across Urban Streams

NASA Astrophysics Data System (ADS)

Kaushal, S. S.; Belt, K. T.; Stack, W. P.; Pouyat, R. V.; Groffman, P. M.; F, S. E.

2006-05-01

Urbanization has led to increased concentrations of metals such as lead (Pb), zinc (Zn), and copper (Cu) in streams due to industrial sources, domestic activities, vehicle use, and runoff from roadways. These metals can be dangerous to aquatic organisms and humans at high concentrations. We investigated variations in concentrations of heavy metals in streams across Baltimore, Maryland and within the context of convergent increases in salinity and organic carbon (two important variables that are known to affect metal transport in surface waters) due to urbanization. Despite past reductions of lead in gasoline and paints, mean concentrations of lead in some Baltimore streams were still approximately 75 micrograms/L and exceeded the U.S. EPA recommended criteria by 50 times. Mean concentrations of zinc and copper across Baltimore streams were also elevated and ranged between 15 to 140 micrograms/L and 2 to 40 micrograms/L, and mean concentrations of these metals were considerably higher than national means reported by the National Storm Water Quality database (NSWQ), which spans 3,770 storm events across the U.S. There were substantial increases in concentrations of heavy metals in streams during storms with greater than 80 percent, 70 percent, and 20 percent of storm samples exceeding recommended U.S. EPA metals criteria for Cu, Pb, and Zn respectively. Relationships between metal concentrations and stream discharge followed different patterns than nitrate and total phosphorus, other regulated pollutants in the Chesapeake Bay watershed, suggesting differences in sources and transport mechanisms within watersheds. Environmental factors such as increasing salinity from deicer use (with chloride concentrations in streams now ranging up to 5 g/L) may contribute to elevated transport of metals through ion exchange and mobilization of metals in soils and sediments. Environmental factors such as increasing organic carbon in urban streams, with ranges of 2 - 16 times greater in suburban and urban streams than forest watersheds, may also act as a vector for transporting metals due to binding capacity. Results show that metals appear to be present in harmful concentrations in many streams in Baltimore, Maryland, but further work is needed to elucidate shifts in the origin of metal pollution (storage in soils and sediments vs. roadway surfaces), and the effects of widespread changes in environmental factors that can potentially enhance their mobilization to streams.

Transient hazard model using radar data for predicting debris flows in Madison County, Virginia

USGS Publications Warehouse

Morrissey, M.M.; Wieczorek, G.F.; Morgan, B.A.

2004-01-01

During the rainstorm of June 27, 1995, roughly 330-750 mm of rain fell within a 16-hour period, initiating floods and over 600 debris flows in a small area (130 km2) of Madison County, VA. We developed a distributed version of Iverson's transient response model for regional slope stability analysis for the Madison County debris flows. This version of the model evaluates pore-pressure head response and factor of safety on a regional scale in areas prone to rainfall-induced shallow (<2-3 m) landslides. These calculations used soil properties of shear strength and hydraulic conductivity from laboratory measurements of soil samples collected from field sites where debris flows initiated. Rainfall data collected by radar every 6 minutes provided a basis for calculating the temporal variation of slope stability during the storm. The results demonstrate that the spatial and temporal variation of the factor of safety correlates with the movement of the storm cell. When the rainstorm was treated as two separate rainfall events and a larger hydraulic conductivity and friction angle than the laboratory values were used, the timing and location of landslides predicted by the model were in closer agreement with eyewitness observations of debris flows. Application of spatially variable initial pre-storm water table depth and soil properties may improve both the spatial and temporal prediction of instability.

7 CFR 1753.48 - Procurement procedures.

Code of Federal Regulations, 2011 CFR

2011-01-01

... that is estimated to cost $250,000, or less, inclusive of labor and materials. (2) The procedures to be...) Materials on hand, until released to the contractor, shall be covered by fire and either wind-storm or... construction are necessary, and the cost of such changes or corrections is properly chargeable to the borrower...

7 CFR 1753.48 - Procurement procedures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... that is estimated to cost $250,000, or less, inclusive of labor and materials. (2) The procedures to be...) Materials on hand, until released to the contractor, shall be covered by fire and either wind-storm or... construction are necessary, and the cost of such changes or corrections is properly chargeable to the borrower...

7 CFR 1753.48 - Procurement procedures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... that is estimated to cost $250,000, or less, inclusive of labor and materials. (2) The procedures to be...) Materials on hand, until released to the contractor, shall be covered by fire and either wind-storm or... construction are necessary, and the cost of such changes or corrections is properly chargeable to the borrower...

7 CFR 1753.48 - Procurement procedures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... that is estimated to cost $250,000, or less, inclusive of labor and materials. (2) The procedures to be...) Materials on hand, until released to the contractor, shall be covered by fire and either wind-storm or... construction are necessary, and the cost of such changes or corrections is properly chargeable to the borrower...

The Global Statistical Response of the Outer Radiation Belt During Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Murphy, K. R.; Watt, C. E. J.; Mann, I. R.; Jonathan Rae, I.; Sibeck, D. G.; Boyd, A. J.; Forsyth, C. F.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J.

2018-05-01

Using the total radiation belt electron content calculated from Van Allen Probe phase space density, the time-dependent and global response of the outer radiation belt during storms is statistically studied. Using phase space density reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and nonadiabatic effects and revealing a clear modality and repeatable sequence of events in storm time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (μ)-dependent behavior in the seed (150 MeV/G), relativistic (1,000 MeV/G), and ultrarelativistic (4,000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, while the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ dependent and occurs at low μ first, appearing to be repeatable from storm to storm.

A Look at Hurricane Matthew from NASA AIRS

NASA Image and Video Library

2016-10-06

Hurricane Matthew, currently an extremely dangerous Category 4 storm on the Saffir-Simpson Hurricane Wind Scale, continues to bear down on the southeastern United States. At 11:27 a.m. PDT (2:27 p.m. EDT and 18:23 UT) today, NASA's Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite observed the storm as its eye was passing over the Bahamas. An AIRS false-color infrared image shows that the northeast and southwest quadrants of the storm had the coldest cloud tops, denoting the regions of the storm where the strongest precipitation was occurring at the time. Data from the Advanced Microwave Sounding Unit (AMSU), another of AIRS' suite of instruments, indicate that the northeast quadrant, which appears smaller in the infrared image, likely had the most intense rain bands at the time. The AIRS infrared image shows that at the time of the image the storm had full circulation, with a small eye surrounded by a thick eye wall and can be seen at http://photojournal.jpl.nasa.gov/catalog/PIA21092.

Changes of loggerhead turtle (Caretta caretta) dive behavior associated with tropical storm passage during the inter-nesting period.

PubMed

Wilson, Maria; Tucker, Anton D; Beedholm, Kristian; Mann, David A

2017-10-01

To improve conservation strategies for threatened sea turtles, more knowledge on their ecology, behavior, and how they cope with severe and changing weather conditions is needed. Satellite and animal motion datalogging tags were used to study the inter-nesting behavior of two female loggerhead turtles in the Gulf of Mexico, which regularly has hurricanes and tropical storms during nesting season. We contrast the behavioral patterns and swimming energetics of these two turtles, the first tracked in calm weather and the second tracked before, during and after a tropical storm. Turtle 1 was highly active and swam at the surface or submerged 95% of the time during the entire inter-nesting period, with a high estimated specific oxygen consumption rate (0.95 ml min -1  kg -0.83 ). Turtle 2 was inactive for most of the first 9 days of the inter-nesting period, during which she rested at the bottom (80% of the time) with low estimated oxygen consumption (0.62 ml min -1  kg -0.83 ). Midway through the inter-nesting period, turtle 2 encountered a tropical storm and became highly active (swimming 88% of the time during and 95% after the storm). Her oxygen consumption increased significantly to 0.97 ml min -1  kg -0.83 during and 0.98 ml min -1  kg -0.83 after the storm. However, despite the tropical storm, turtle 2 returned to the nesting beach, where she successfully re-nested 75 m from her previous nest. Thus, the tropical storm had a minor effect on this female's individual nesting success, even though the storm caused 90% loss nests at Casey Key. © 2017. Published by The Company of Biologists Ltd.

Seasonal Extratropical Storm Activity Potential Predictability and its Origins during the Cold Seasons

NASA Astrophysics Data System (ADS)

Pingree-Shippee, K. A.; Zwiers, F. W.; Atkinson, D. E.

2016-12-01

Extratropical cyclones (ETCs) often produce extreme hazardous weather conditions, such as high winds, blizzard conditions, heavy precipitation, and flooding, all of which can have detrimental socio-economic impacts. The North American east and west coastal regions are both strongly influenced by ETCs and, subsequently, land-based, coastal, and maritime economic sectors in Canada and the USA all experience strong adverse impacts from extratropical storm activity from time to time. Society would benefit if risks associated with ETCs and storm activity variability could be reliably predicted for the upcoming season. Skillful prediction would enable affected sectors to better anticipate, prepare for, manage, and respond to storm activity variability and the associated risks and impacts. In this study, the potential predictability of seasonal variations in extratropical storm activity is investigated using analysis of variance to provide quantitative and geographical observational evidence indicative of whether it may be possible to predict storm activity on the seasonal timescale. This investigation will also identify origins of the potential predictability using composite analysis and large-scale teleconnections (Southern Oscillation, Pacific Decadal Oscillation, and North Atlantic Oscillation), providing the basis upon which seasonal predictions can be developed. Seasonal potential predictability and its origins are investigated for the cold seasons (OND, NDJ, DJF, JFM) during the 1979-2015 time period using daily mean sea level pressure, absolute pressure tendency, and 10-m wind speed from the ECMWF ERA-Interim reanalysis as proxies for extratropical storm activity. Results indicate potential predictability of seasonal variations in storm activity in areas strongly influenced by ETCs and with origins in the investigated teleconnections. For instance, the North Pacific storm track has considerable potential predictability and with notable origins in the SO and PDO.

Method and system for photoconductive detector signal correction

DOEpatents

Carangelo, Robert M.; Hamblen, David G.; Brouillette, Carl R.

1992-08-04

A corrective factor is applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factor may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects.

Method and system for photoconductive detector signal correction

DOEpatents

Carangelo, R.M.; Hamblen, D.G.; Brouillette, C.R.

1992-08-04

A corrective factor is applied so as to remove anomalous features from the signal generated by a photoconductive detector, and to thereby render the output signal highly linear with respect to the energy of incident, time-varying radiation. The corrective factor may be applied through the use of either digital electronic data processing means or analog circuitry, or through a combination of those effects. 5 figs.

Water Vapor Reaches Mars' Middle Atmosphere During Global Dust Storm

NASA Image and Video Library

2018-01-23

Rising air during a 2007 global dust storm on Mars lofted water vapor into the planet's middle atmosphere, researchers learned from data graphed here, derived from observations by the Mars Climate Sounder instrument on NASA's Mars Reconnaissance Orbiter. The two vertical black lines in the right half of the graph (at about 260 and 310 on the horizontal scale) mark the beginning and end of the most recent global dust storm on Mars, which burst from regional scale to globe-encircling scale in July 2007. The presence of more colored dots, particularly green ones, in the upper portion of the graph between those lines, compared to the upper portion of the graph outside those lines, documents the uplift of water vapor in connection with the global dust storm. The vertical scale is altitude, labeled at left in kilometers above the surface of Mars (50 kilometers is about 30 miles; 80 kilometers is about 50 miles). The color bar below the graph gives the key to how much water vapor each dot represents, in parts per million, by volume, in Mars' atmosphere. Note that green to yellow represents about 100 times as much water as purple does. The horizontal axis of the graph is time, from January 2006 to February 2008. It is labeled with numbers representing the 360 degrees of Mars' orbit around the Sun, from zero to 360 degrees and then further on to include the first 30 degrees of the following Martian year. (The zero point is autumnal equinox -- end of summer -- in Mars' northern hemisphere.) This graph, based on Mars Reconnaissance Orbiter observations, was used in a January 2018 paper in Nature Astronomy by Nicholas Heavens of Hampton University in Hampton, Virginia, and co-authors. The paper presents Martian dust storms' uplifting effect on water vapor as a factor in seasonal patterns that other spacecraft have detected in the rate of hydrogen escaping from the top of Mars' atmosphere. https://photojournal.jpl.nasa.gov/catalog/PIA22080

Biological-Physical Feedbacks Determine Coastal Environmental Response to Climate Change

NASA Astrophysics Data System (ADS)

Moore, L. J.; Duran Vinent, O.; Walters, D.; Fagherazzi, S.; Mariotti, G.; Young, D.; Wolner, C. V.

2012-12-01

As low-lying coastal landforms, transitional between marine and terrestrial realms, barrier islands are especially sensitive to changing environmental conditions. Interactions among biological and physical processes appear to play a critical role in determining how these landscapes will evolve in the future as sea level rises, storm intensity increases and plant species composition changes. Within a new conceptual framework, barrier islands tend to exist in one of two primary states. "Low" islands have little relief above sea level and are dominated by external processes, responding quickly on short time scales to changes in forcing (e.g., storms, sea level rise, etc.), migrating rapidly and generally being low in ecological diversity and productivity. In contrast, "high" islands are less vulnerable to storms, tend to be dominated by internal processes (e.g., sand trapping by vegetation), require long time periods to respond to changes in forcing, migrate slowly (if at all) and host a range of plant species and morphological environments including shrubs, small trees and vegetated secondary and tertiary dunes with intervening swales. The continued existence of barrier island landforms will depend on the degree to which islands can maintain elevation above sea level while also responding to changes in forcing by migrating landward. A long-term morphological-behavior model exploring coupled barrier-marsh evolution and a new ecomorphodynamic model representing the formation/recovery of dunes as a function of storms, shed light on the role of interactions among biological and physical processes on barrier island response to climate change. Results suggest that connections between the marsh and barrier realms, which are mediated by biological processes in the marsh environment, are highly sensitive to factors such as sea level rise rate, antecedent morphology and marsh composition. Results also suggest that feedbacks between sediment transport and vegetation involved in dune building may allow small, gradual changes in storms to cause abrupt, nonlinear transitions from the high to low island state.

Effects of acid deposition on dissolution of carbonate stone during summer storms in the Adirondack Mountains, New York, 1987-89

USGS Publications Warehouse

Schuster, Paul F.; Reddy, Michael M.; Sherwood, S.I.

1994-01-01

This study is part of a long-term research program designed to identify and quantify acid rain damage to carbonate stone. Acidic deposition accelerates the dissolution of carbonate-stone monuments and building materials. Sequential sampling of runoff from carbonate-stone (marble) and glass (reference) microcatchments in the Adirondack Mountains in New York State provided a detailed record of the episodic fluctuations in rain rate and runoff chemistry during individual summer storms. Rain rate and chemical concentrations from carbonate-stone and glass runoff fluctuated three to tenfold during storms. Net calcium-ion concentrations from the carbonatestone runoff, a measure of stone dissolution, typically fluctuated twofold during these storms. High net sulfate and net calcium concentrations in the first effective runoff at the start of a storm indicated that atmospheric pollutants deposited on the stone surface during dry periods formed calcium sulfate minerals, an important process in carbonate stone dissolution. Dissolution of the carbonate stone generally increased up to twofold during coincident episodes of low rain rate (less than 5 millimeters per hour) and decreased rainfall (glass runoff) pH (less than 4.0); episodes of high rain rate (cloudbursts) were coincident with a rapid increase in rainfall pH and also a rapid decrease in the dissolution of carbonate-stone. During a storm, it seems the most important factors causing increased dissolution of carbonate stone are coincident periods of low rain rate and decreased rainfall pH. Dissolution of the carbonate stone decreased slightly as the rain rate exceeded about 5 millimeters per hour, probably in response to rapidly increasing rainfall pH during episodes of high rain rate and shorter contact time between the runoff and the stone surface. High runoff rates resulting from cloudbursts remove calcium sulfate minerals formed during dry periods prior to storms and also remove dissolution products formed in large measure by chemical weathering as a result of episodes of low rain rate and decreased rainfall pH during a storm.

Accurately Characterizing the Importance of Wave-Particle Interactions in Radiation Belt Dynamics: The Pitfalls of Statistical Wave Representations

NASA Technical Reports Server (NTRS)

Murphy, Kyle R.; Mann, Ian R.; Rae, I. Jonathan; Sibeck, David G.; Watt, Clare E. J.

2016-01-01

Wave-particle interactions play a crucial role in energetic particle dynamics in the Earths radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power.

GPU-Meta-Storms: computing the structure similarities among massive amount of microbial community samples using GPU.

PubMed

Su, Xiaoquan; Wang, Xuetao; Jing, Gongchao; Ning, Kang

2014-04-01

The number of microbial community samples is increasing with exponential speed. Data-mining among microbial community samples could facilitate the discovery of valuable biological information that is still hidden in the massive data. However, current methods for the comparison among microbial communities are limited by their ability to process large amount of samples each with complex community structure. We have developed an optimized GPU-based software, GPU-Meta-Storms, to efficiently measure the quantitative phylogenetic similarity among massive amount of microbial community samples. Our results have shown that GPU-Meta-Storms would be able to compute the pair-wise similarity scores for 10 240 samples within 20 min, which gained a speed-up of >17 000 times compared with single-core CPU, and >2600 times compared with 16-core CPU. Therefore, the high-performance of GPU-Meta-Storms could facilitate in-depth data mining among massive microbial community samples, and make the real-time analysis and monitoring of temporal or conditional changes for microbial communities possible. GPU-Meta-Storms is implemented by CUDA (Compute Unified Device Architecture) and C++. Source code is available at http://www.computationalbioenergy.org/meta-storms.html.

Examining Hurricane Track Length and Stage Duration Since 1980

NASA Astrophysics Data System (ADS)

Fandrich, K. M.; Pennington, D.

2017-12-01

Each year, tropical systems impact thousands of people worldwide. Current research shows a correlation between the intensity and frequency of hurricanes and the changing climate. However, little is known about other prominent hurricane features. This includes information about hurricane track length (the total distance traveled from tropical depression through a hurricane's final category assignment) and how this distance may have changed with time. Also unknown is the typical duration of a hurricane stage, such as tropical storm to category one, and if the time spent in each stage has changed in recent decades. This research aims to examine changes in hurricane stage duration and track lengths for the 319 storms in NOAA's National Ocean Service Hurricane Reanalysis dataset that reached Category 2 - 5 from 1980 - 2015. Based on evident ocean warming, it is hypothesized that a general increase in track length with time will be detected, thus modern hurricanes are traveling a longer distance than past hurricanes. It is also expected that stage durations are decreasing with time so that hurricanes mature faster than in past decades. For each storm, coordinates are acquired at 4-times daily intervals throughout its duration and track lengths are computed for each 6-hour period. Total track lengths are then computed and storms are analyzed graphically and statistically by category for temporal track length changes. The stage durations of each storm are calculated as the time difference between two consecutive stages. Results indicate that average track lengths for Cat 2 and 3 hurricanes are increasing through time. These findings show that these hurricanes are traveling a longer distance than earlier Cat 2 and 3 hurricanes. In contrast, average track lengths for Cat 4 and 5 hurricanes are decreasing through time, showing less distance traveled than earlier decades. Stage durations for all Cat 2, 4 and 5 storms decrease through the decades but Cat 3 storms show a positive increase though time. This compliments the results of the track length analysis indicating that as storms intensify faster, they are doing so over a shorter distance. It is expected that this research could be used to improve hurricane track forecasting and provide information about the effects of climate change on tropical systems and the tropical environment.

Examples of storm impacts on barrier islands: Chapter 4

USGS Publications Warehouse

Plant, Nathaniel G.; Doran, Kara; Stockdon, Hilary F.

2017-01-01

This chapter focuses on the morphologic variability of barrier islands and on the differences in storm response. It describes different types of barrier island response to individual storms, as well as the integrated response of barrier islands to many storms. The chapter considers case study on the Chandeleur Island chain, where a decadal time series of island elevation measurements have documented a wide range of barrier island responses to storms and long-term processes that are representative of barrier island behaviour at many other locations. These islands are low elevation, extremely vulnerable to storms and exhibit a diversity of storm responses. Additionally, this location experiences a moderately high rate of relative sea-level rise, increasing its vulnerability to the combined impacts of storms and long-term erosional processes. Understanding how natural processes, including storm impacts and intervening recovery periods interact with man-made restoration processes is also broadly relevant to understand the natural and human response to future storms.

NOAA Weather Radio - Alarms

Science.gov Websites

affected (usually by county), and the expiration time of the message. The Maximum message expiration time county), and the valid time period of the hazard. Other details, such as storm movement, storm spotter time in SAME vs. valid time period in voice message: For short-fuse hazards, such as a tornado warning

A FODO racetrack ring for nuSTORM: design and optimization

DOE PAGES

Liu, A.; Bross, A.; Neuffer, D.

2017-07-17

Here, the goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ~ 480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS . Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize themore » arc length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.« less

Aircraft Observation of Gravity Wave Breaking at the Storm Top and Comparison with High Resolution Cloud Model Simulations and Satellite Images

NASA Astrophysics Data System (ADS)

Wang, P. K.; Cheng, K. Y.; Lindsey, D. T.

2017-12-01

Deep convective clouds play an important role in the transport of momentum, energy, and chemical species from the surface to upper troposphere and lower stratosphere (UT/LS), but exactly how these processes occur and how important they are as compared to other processes are still up to debate. The main hurdle to the complete understanding of these transport processes is the difficulty in observing storm systems directly. Remote sensing data such as those obtained by radars and satellites are very valuable but they need correct interpretation before we can use them profitably. We have performed numerical simulations of thunderstorms using a physics-based cloud resolving model and compared model results with satellite observations. Many major features of observed satellite storm top images, such as cold-V, close in warm area, above anvil cirrus plumes, are successfully simulated and can be interpreted by the model physics. However, due to the limitation of resolution and other ambiguities, we have been unable to determine the real cause of some features such as the conversion of jumping cirrus to long trail plumes and whether or no small scale ( < 1 km) wave breaking occur. We are fortunate to have encountered a line of sea breeze storms along the coast of China during a flight from Beijing to Taipei in July 2106. The flight was at an altitude such that storm tops could be clearly observed. Nearly all of the mature storm cells that can be identified had very vigorous storm top activities, indicating very strong stratosphere/troposphere exchange (STE). There is no doubt that the signatures of wave breaking, i.e., jumping cirrus, occurs from very small scale (< 1 km) to tens of km. this matches our previous model results very well. Furthermore, one storm cell shows very clearly the process whereby a jumping cirrus is being transformed into a long trail cirrus plume which was often observed in satellite images. We have also obtained the corresponding Himawari-8 satellite images for this line of storms. Aircraft observation, satellite images and model results will be compared and the implications to STE discussed.

Challenges associated with the prediction of tropical storms in the Bay of Bengal when using the WRF model

NASA Astrophysics Data System (ADS)

Machineni, N.; Veldore, V.; Mesquita, M. D. S.

2016-12-01

Accuracy in predicting tropical cyclones over low lying coastal regions is pivotal for understanding storm tracks and their subsequent impacts. The present study highlights the challenges in predicting the Bay of Bengal (BOB) cyclone "AILA" (during 23rd to 25th May 2009) using the Weather Research and Forecast model, Advanced research core module (WRF-ARW). The model configuration uses a two-way interactive nested domain with 10 km resolution over BOB. Its initial and boundary conditions are driven from the NCEP FNL operational global analysis data at every 6 hours. A total of 74 sensitivity experiments were conducted to test the following factors and levels: a) parametrization schemes: two microphysics and two cumulus physics schemes used to select appropriate combination over study region, b) model domain:including/excluding Himalayas, c) vertical resolution: eight various increasing/decreasing vertical levels have been carried out to evaluate the storm track dependencies on these factors, d) domain size: and increasing (decreasing) the grid points of model domain in east-west direction shows that approximately 50-100 km track difference for every two points. Our results show that, the experiments including the Himalayas provide a better representation of cyclone track and speed. In order to reduce the computational time required to do such tremendous amount of experiment, we hypothesize to use statistical tools of experimental design which can involve all the factors that determine the cyclone tracks. A proper experimental design might provide unbiased results and also we might need less number of experiments.

Challenges associated with the prediction of tropical storms in the Bay of Bengal when using the WRF model

NASA Astrophysics Data System (ADS)

Machineni, Nehru; Veldore, Vidyunmala; Mesquita, Michel d. S.

2017-04-01

Accuracy in predicting tropical cyclones over low lying coastal regions is pivotal for understanding storm tracks and their subsequent impacts. The present study highlights the challenges in predicting the Bay of Bengal (BOB) cyclone "AILA" (during 23rd to 25th May 2009) using the Weather Research and Forecast model, Advanced research core module (WRF-ARW). The model configuration uses a two-way interactive nested domain with 10 km resolution over BOB. Its initial and boundary conditions are driven from the NCEP FNL operational global analysis data at every 6 hours. A total of 74 sensitivity experiments were conducted to test the following factors and levels: a) parametrization schemes: two microphysics and two cumulus physics schemes used to select appropriate combination over study region, b) model domain:including/excluding Himalayas, c) vertical resolution: eight various increasing/decreasing vertical levels have been carried out to evaluate the storm track dependencies on these factors, d) domain size: and increasing (decreasing) the grid points of model domain in east-west direction shows that approximately 50-100 km track difference for every two points. Our results show that, the experiments including the Himalayas provide a better representation of cyclone track and speed. In order to reduce the computational time required to do such tremendous amount of experiment, we hypothesize to use statistical tools of experimental design which can involve all the factors that determine the cyclone tracks. A proper experimental design might provide unbiased results and also we might need less number of experiments.

A maintenance time prediction method considering ergonomics through virtual reality simulation.

PubMed

Zhou, Dong; Zhou, Xin-Xin; Guo, Zi-Yue; Lv, Chuan

2016-01-01

Maintenance time is a critical quantitative index in maintainability prediction. An efficient maintenance time measurement methodology plays an important role in early stage of the maintainability design. While traditional way to measure the maintenance time ignores the differences between line production and maintenance action. This paper proposes a corrective MOD method considering several important ergonomics factors to predict the maintenance time. With the help of the DELMIA analysis tools, the influence coefficient of several factors are discussed to correct the MOD value and the designers can measure maintenance time by calculating the sum of the corrective MOD time of each maintenance therbligs. Finally a case study is introduced, by maintaining the virtual prototype of APU motor starter in DELMIA, designer obtains the actual maintenance time by the proposed method, and the result verifies the effectiveness and accuracy of the proposed method.

Geospace system responses to the St. Patrick's Day storms in 2013 and 2015

NASA Astrophysics Data System (ADS)

Zhang, Shun-Rong; Zhang, Yongliang; Wang, Wenbin; Verkhoglyadova, Olga P.

2017-06-01

This special collection includes 31 research papers investigating geospace system responses to the geomagnetic storms during the St. Patrick's Days of 17 March 2013 and 2015. It covers observation, data assimilation, and modeling aspects of the storm time phenomena and their associated physical processes. The ionosphere and thermosphere as well as their coupling to the magnetosphere are clearly the main subject areas addressed. This collection provides a comprehensive picture of the geospace response to these two major storms. We provide some highlights of these studies in six specific areas: (1) global and magnetosphere/plasmasphere perspectives, (2) high-latitude responses, (3) subauroral and midlatitude processes, (4) effects of prompt penetration electric fields and disturbance dynamo electric fields, (5) effects of neutral dynamics and perturbation, and (6) storm effects on plasma bubbles and irregularities. We also discuss areas of future challenges and the ways to move forward in advancing our understanding of the geospace storm time behavior and space weather effects.

Assessment of coastal flood risk in a changing climate along the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.; Passeri, D. L.; Alizad, K.

2014-12-01

Coastal regions around the world are susceptible to a variety of natural disasters causing extreme inundation. It is anticipated that the vulnerability of coastal cities will increase due to the effects of climate change, and in particular sea level rise (SLR). We have developed a novel framework to construct a physics-based storm surge model that includes projections of coastal floodplain dynamics under climate change scenarios. Numerous experiments were conducted and it was concluded that a number of influencing factors, other than SLR, should be included in future assessments of coastal flooding under climate change; e.g., shoreline changes, barrier island morphology, salt marsh migration, and population dynamics. These factors can significantly affect the path, pattern, and magnitude of flooding depths and inundation along the coastline (Bilskie et al., 2014; Passeri et al., 2014). Using these factors, a storm surge model of the northern Gulf of Mexico (NGOM) representing present day conditions is modified to characterize the future outlook of the landscape. This adapted model is then used to assess flood risk in terms of the 100-year floodplain surface under SLR scenarios. A suite of hundreds of synthetic storms, derived by JPM-OS (Joint Probability Method - Optimum Sampling), are filtered to obtain the storms necessary to represent the statistically determined 100-year floodplain. The NGOM storm surge model is applied to simulate the synthetic storms and determine, for each storm, the flooding surface and depth, for four SLR scenarios for the year 2100 as prescribed by Parris et al. (2012). The collection of results facilitate the estimation of water surface elevation vs. frequency curves across the floodplain and the statistically defined 100-year floodplain is extracted. This novel method to assess coastal flooding under climate change can be performed across any coastal region worldwide, and results provide awareness of regions vulnerable to extreme flooding in the future.

Empirical model for the electron density peak height disturbance in response to solar wind conditions

NASA Astrophysics Data System (ADS)

Blanch, E.; Altadill, D.

2009-04-01

Geomagnetic storms disturb the quiet behaviour of the ionosphere, its electron density and the electron density peak height, hmF2. Many works have been done to predict the variations of the electron density but few efforts have been dedicated to predict the variations the hmF2 under disturbed helio-geomagnetic conditions. We present the results of the analyses of the F2 layer peak height disturbances occurred during intense geomagnetic storms for one solar cycle. The results systematically show a significant peak height increase about 2 hours after the beginning of the main phase of the geomagnetic storm, independently of both the local time position of the station at the onset of the storm and the intensity of the storm. An additional uplift is observed in the post sunset sector. The duration of the uplift and the height increase are dependent of the intensity of the geomagnetic storm, the season and the local time position of the station at the onset of the storm. An empirical model has been developed to predict the electron density peak height disturbances in response to solar wind conditions and local time which can be used for nowcasting and forecasting the hmF2 disturbances for the middle latitude ionosphere. This being an important output for EURIPOS project operational purposes.

Serial profiles of electrostatic potential in five New Mexico thunderstorms

NASA Astrophysics Data System (ADS)

Stolzenburg, Maribeth; Marshall, Thomas C.

2008-07-01

Profiles of electric potential (V) integrated from balloon-borne electric field (E) measurements are used to investigate the electrical evolution of thunderstorms over the mountains in central New Mexico. With sequential soundings through multiple storms, the time skew associated with obtaining V from a noninstantaneous sounding is also studied. The data show that a basic V profile, with a maximum above a minimum, forms in the early stage of the storm and is maintained throughout its mature stage. Series of soundings from individual storms show only a gradual evolution in the V profile from the early through the mature stage, as the extrema descend in altitude and become shallower and vertically closer together. More evolution occurs in the late stage, when the shape of the V profile reverses to have a minimum above a maximum. The 17 V(z) profiles from the mature stage of five different storms are also very similar in overall shape, suggesting that the basic shape is not significantly affected by differences in lightning flash rate among these storms. The findings indicate that the potential profile during a typical sounding in the mature stage is relatively stable, and the overall shape of the mature stage V profile does not change markedly on the time scale of a particular balloon sounding (10-30 min) through New Mexico mountain storms. Thus time-skew problems in the V profiles are minor during a storm's mature stage.

Determination of velocity correction factors for real-time air velocity monitoring in underground mines.

PubMed

Zhou, Lihong; Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-12-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction factors of the sensor-measured air velocity to the average air velocity at cross sections are still lacking. A comprehensive airflow measurement was made at the Safety Research Coal Mine, Bruceton, PA, using three measuring methods including single-point reading, moving traverse, and fixed-point traverse. The air velocity distribution at each measuring station was analyzed using an air velocity contour map generated with Surfer ® . The correction factors at each measuring station for both the centerline and the sensor location were calculated and are discussed.

Determination of velocity correction factors for real-time air velocity monitoring in underground mines

PubMed Central

Yuan, Liming; Thomas, Rick; Iannacchione, Anthony

2017-01-01

When there are installations of air velocity sensors in the mining industry for real-time airflow monitoring, a problem exists with how the monitored air velocity at a fixed location corresponds to the average air velocity, which is used to determine the volume flow rate of air in an entry with the cross-sectional area. Correction factors have been practically employed to convert a measured centerline air velocity to the average air velocity. However, studies on the recommended correction factors of the sensor-measured air velocity to the average air velocity at cross sections are still lacking. A comprehensive airflow measurement was made at the Safety Research Coal Mine, Bruceton, PA, using three measuring methods including single-point reading, moving traverse, and fixed-point traverse. The air velocity distribution at each measuring station was analyzed using an air velocity contour map generated with Surfer®. The correction factors at each measuring station for both the centerline and the sensor location were calculated and are discussed. PMID:29201495

Skill assessment of a real-time forecast system utilizing a coupled hydrologic and coastal hydrodynamic model during Hurricane Irene (2011)

NASA Astrophysics Data System (ADS)

Dresback, Kendra M.; Fleming, Jason G.; Blanton, Brian O.; Kaiser, Carola; Gourley, Jonathan J.; Tromble, Evan M.; Luettich, Richard A.; Kolar, Randall L.; Hong, Yang; Van Cooten, Suzanne; Vergara, Humberto J.; Flamig, Zac L.; Lander, Howard M.; Kelleher, Kevin E.; Nemunaitis-Monroe, Kodi L.

2013-12-01

Due to the devastating effects of recent hurricanes in the Gulf of Mexico (e.g., Katrina, Rita, Ike and Gustav), the development of a high-resolution, real-time, total water level prototype system has been accelerated. The fully coupled model system that includes hydrology is an extension of the ADCIRC Surge Guidance System (ASGS), and will henceforth be referred to as ASGS-STORM (Scalable, Terrestrial, Ocean, River, Meteorological) to emphasize the major processes that are represented by the system.The ASGS-STORM system incorporates tides, waves, winds, rivers and surge to produce a total water level, which provides a holistic representation of coastal flooding. ASGS-STORM was rigorously tested during Hurricane Irene, which made landfall in late August 2011 in North Carolina. All results from ASGS-STORM for the advisories were produced in real-time, forced by forecast wind and pressure fields computed using a parametric tropical cyclone model, and made available via the web. Herein, a skill assessment, analyzing wind speed and direction, significant wave heights, and total water levels, is used to evaluate ASGS-STORM's performance during Irene for three advisories and the best track from the National Hurricane Center (NHC). ASGS-STORM showed slight over-prediction for two advisories (Advisory 23 and 25) due to the over-estimation of the storm intensity. However, ASGS-STORM shows notable skill in capturing total water levels, wind speed and direction, and significant wave heights in North Carolina when utilizing Advisory 28, which had a slight shift in the track but provided a more accurate estimation of the storm intensity, along with the best track from the NHC. Results from ASGS-STORM have shown that as the forecast of the advisories improves, so does the accuracy of the models used in the study; therefore, accurate input from the weather forecast is a necessary, but not sufficient, condition to ensure the accuracy of the guidance provided by the system. While Irene provided a real-time test of the viability of a total water level system, the relatively insignificant freshwater discharges precludes definitive conclusions about the role of freshwater discharges on total water levels in estuarine zones. Now that the system has been developed, on-going work will examine storms (e.g., Floyd) for which the freshwater discharge played a more meaningful role.

Trends in the components of extreme water levels signal a rotation of winds in strong storms in the eastern Baltic Sea

NASA Astrophysics Data System (ADS)

Pindsoo, Katri; Soomere, Tarmo

2016-04-01

The water level time series and particularly temporal variations in water level extremes usually do not follow any simple rule. Still, the analysis of linear trends in extreme values of surge levels is a convenient tool to obtain a first approximation of the future projections of the risks associated with coastal floodings. We demonstrate how this tool can be used to extract essential information about concealed changes in the forcing factors of seas and oceans. A specific feature of the Baltic Sea is that sequences of even moderate storms may raise the average sea level by almost 1 m for a few weeks. Such events occur once in a few years. They substantially contribute to the extreme water levels in the eastern Baltic Sea: the most devastating coastal floodings occur when a strong storm from unfortunate direction arrives during such an event. We focus on the separation of subtidal (weekly-scale) processes from those which are caused by a single storm and on establishing how much these two kinds of events have contributed to the increase in the extreme water levels in the eastern Baltic Sea. The analysis relies on numerically reconstructed sea levels produced by the RCO (Rossby Center, Swedish Meteorological and Hydrological Institute) ocean model for 1961-2005. The reaction of sea surface to single storm events is isolated from the local water level time series using a running average over a fixed interval. The distribution of average water levels has an almost Gaussian shape for averaging lengths from a few days to a few months. The residual (total water level minus the average) can be interpreted as a proxy of the local storm surges. Interestingly, for the 8-day average this residual almost exactly follows the exponential distribution. Therefore, for this averaging length the heights of local storm surges reflect an underlying Poisson process. This feature is universal for the entire eastern Baltic Sea coast. The slopes of the exponential distribution for low and high water levels are different, vary markedly along the coast and provide a useful quantification of the vulnerability of single coastal segments with respect to coastal flooding. The formal linear trends in the extreme values of these water level components exhibit radically different spatial variations. The slopes of the trends in the weekly average are almost constant (~4 cm/decade for 8-day running average) along the entire eastern Baltic Sea coast. This first of all indicates that the duration of storm sequences has increased. The trends for maxima of local storm surge heights represent almost the entire spatial variability in the water level extremes. Their slopes are almost zero at the open Baltic Proper coasts of the Western Estonian archipelago. Therefore, an increase in wind speed in strong storms is unlikely in this area. In contrast, the slopes in question reach 5-7 cm/decade in the eastern Gulf of Finland and Gulf of Riga. This feature suggests that wind direction in strongest storms may have rotated in the northern Baltic Sea.

Learning time-dependent noise to reduce logical errors: real time error rate estimation in quantum error correction

NASA Astrophysics Data System (ADS)

Huo, Ming-Xia; Li, Ying

2017-12-01

Quantum error correction is important to quantum information processing, which allows us to reliably process information encoded in quantum error correction codes. Efficient quantum error correction benefits from the knowledge of error rates. We propose a protocol for monitoring error rates in real time without interrupting the quantum error correction. Any adaptation of the quantum error correction code or its implementation circuit is not required. The protocol can be directly applied to the most advanced quantum error correction techniques, e.g. surface code. A Gaussian processes algorithm is used to estimate and predict error rates based on error correction data in the past. We find that using these estimated error rates, the probability of error correction failures can be significantly reduced by a factor increasing with the code distance.

Ionospheric convection during the magnetic storm of 20-21 March 1991

NASA Technical Reports Server (NTRS)

Taylor, J. R.; Yeoman, T. K.; Lester, M.; Buonsanto, M. J.; Scali, J. L.; Ruohoniemi, J. M.; Kelly, J. D.

1994-01-01

We report on the response of high-latitude ionospheric convection during the magnetic storm of March 20-21 1990. IMP-8 measurements of solar wind plasma and interplanetary magnetic field (IMF), ionospheric convection flow measurements from the Wick and Goose Bay coherent radars, EISCAT, Millstone Hill and Sondrestorm incoherent radars and three digisondes at Millstone Hill, Goose Bay and Qaanaaq are presented. Two intervals of particular interest have been indentified. The first starts with a storm sudden commencement at 2243 UT on March 20 and includes the ionospheric activity in the following 7 h. The response time of the ionospheric convection to the southward tuning of the IMF in the dusk to midnight local times is found to be approximately half that measured in a similar study at comparable local times during more normal solar wind conditions. A subsequent reconfiguration of the nightside convection pattern was also observed, although it was not possible to distinguish between effects due to possible changes in B(sub y) and effects due to substorm activity. The second interval, 1200-2100 UT 21 March 1990, included a southward turning of the IMF which resulted in the B(sub z) component becoming -10 nT. The response time on the dayside to this change in the IMF at the magnetopause was approximately 15 min to 30 min which is a factor of approximately 2 greater than those previously measured at higher latitudes. A movement of the nightside flow reversal, possibly driven by current systems associated with the substorm expansion phases, was observed, implying that the nightside convection pattern can be dominated by substorm activity.

Association of time of occurrence of electrical heart storms with environmental physical activity.

PubMed

Stoupel, Eliiyahu; Kusniec, Jairo; Golovchiner, Gregory; Abramson, Evgeny; Kadmon, Udi; Strasberg, Boris

2014-08-01

Many publications in recent decades have reported a temporal link between medical events and environmental physical activity. The aim of this study was to analyze the time of occurrence of electrical heart storms against levels of cosmological parameters. The sample included 82 patients (71 male) with ischemic cardiomyopathy treated with an implantable cardioverter defibrillator at a tertiary medical center in 1999-2012 (5,114 days). The time of occurrence of all electrical heart storms, defined as three or more events of ventricular tachycardia or ventricular fibrillation daily, was recorded from the defibrillator devices. Findings were analyzed against data on solar, geomagnetic, and cosmic ray (neutron) activity for the same time period obtained from space institutions in the United States and Russia. Electrical storms occurred in all months of the year, with a slight decrease in July, August, and September. Most events took place on days with lower-than-average levels of solar and geomagnetic activity and higher-than-average levels of cosmic ray (neutron) activity. There was a significant difference in mean daily cosmic ray activity between the whole observation period and the days of electrical storm activity (P = 0.0001). These data extend earlier findings on the association of the timing of cardiac events and space weather parameters to the most dangerous form of cardiac arrhythmia-electric storms. Further studies are needed to delineate the pathogenetic mechanism underlying this association. ©2014 Wiley Periodicals, Inc.

Precipitation areal-reduction factor estimation using an annual-maxima centered approach

NASA Astrophysics Data System (ADS)

Asquith, W. H.; Famiglietti, J. S.

2000-04-01

The adjustment of precipitation depth of a point storm to an effective (mean) depth over a watershed is important for characterizing rainfall-runoff relations and for cost-effective designs of hydraulic structures when design storms are considered. A design storm is the precipitation point depth having a specified duration and frequency (recurrence interval). Effective depths are often computed by multiplying point depths by areal-reduction factors (ARF). ARF range from 0 to 1, vary according to storm characteristics, such as recurrence interval; and are a function of watershed characteristics, such as watershed size, shape, and geographic location. This paper presents a new approach for estimating ARF and includes applications for the 1-day design storm in Austin, Dallas, and Houston, Texas. The approach, termed "annual-maxima centered," specifically considers the distribution of concurrent precipitation surrounding an annual-precipitation maxima, which is a feature not seen in other approaches. The approach does not require the prior spatial averaging of precipitation, explicit determination of spatial correlation coefficients, nor explicit definition of a representative area of a particular storm in the analysis. The annual-maxima centered approach was designed to exploit the wide availability of dense precipitation gauge data in many regions of the world. The approach produces ARF that decrease more rapidly than those from TP-29. Furthermore, the ARF from the approach decay rapidly with increasing recurrence interval of the annual-precipitation maxima.

Can we predict seasonal changes in high impact weather in the United States?

NASA Astrophysics Data System (ADS)

Jung, Eunsil; Kirtman, Ben P.

2016-07-01

Severe convective storms cause catastrophic losses each year in the United States, suggesting that any predictive capability is of great societal benefit. While it is known that El Niño and the Southern Oscillation (ENSO) influence high impact weather events, such as a tornado activity and severe storms, in the US during early spring, this study highlights that the influence of ENSO on US severe storm characteristics is weak during May-July. Instead, warm water in the Gulf of Mexico is a potential predictor for moist instability, which is an important factor in influencing the storm characteristics in the US during May-July.

Impacts of winter storms on air-sea gas exchange

NASA Astrophysics Data System (ADS)

Zhang, Weiqing; Perrie, Will; Vagle, Svein

2006-07-01

The objective of this study is to investigate air-sea gas exchange during winter storms, using field measurements from Ocean Station Papa in the Northeast Pacific (50°N, 145°W). We show that increasing gas transfer rates are coincident with increasing winds and deepening depth of bubble penetration, and that this process depends on sea state. Wave-breaking is shown to be an important factor in the gas transfer velocity during the peaks of the storms, increasing the flux rates by up to 20%. Gas transfer rates and concentrations can exhibit asymmetry, reflecting a sudden increase with the onset of a storm, and gradual recovery stages.

75 FR 29389 - National Hurricane Preparedness Week, 2010

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-26

... inland communities face the danger of these powerful storms. From high winds and storm surges to... emergency communications, and empowering more families to prepare themselves. Thanks to advancements in... individuals, families, communities, and businesses to take time to plan for the storm season before it begins...

Storm surges - a globally distributed risk, and the case of Hamburg (Invited)

NASA Astrophysics Data System (ADS)

von Storch, H.

2010-12-01

For most coasts, storm surges represent the major geo risk. A map of these risks shows that the phenomenon is really a global phenomenon. However, when discussing dynamics, risks, adaptation, future perspectives as well as aggravating local factors, the situation is mostly perceived as a regional or even local phenomenon. In the talk first the different manifestations of storm surges, mainly at mid latitudes and in the tropics are discussed; the historical perceptions of such events are touched upon, projection for the future presented and issues of management and adaptation discussed. In a second part, a specific situation is discussed, namely the case of Hamburg since 1750. This case is particularly interesting, because specific analysis has been done for past variability, possible future developments; local perceptions of risk and un-conventional mitigation measures. For the time prior to 1850, coastal defence failure was a regular phenomenon; from about 1850-1960 coastal defence was hardly challenged, and after the 1962 storm surge heights rose to levels never recorded before. The most likely causes for this change are modifications of the Elbe estuary, related to coastal defence and improving the shipping channel. Anthropogenic climate change may lead in the future to even higher storm surges (mainly because of increased sea level). While for the foreseeable future, conventional measures will be sufficient for ensuring coastal defence, a mitigation option of local mitigation of high water levels seems to be available. This may be achieved though the "tidal Elbe project", which was designed to reduce upstream river sediment transport.

Ionospheric storms—A challenge for empirical forecast of the total electron content

NASA Astrophysics Data System (ADS)

Borries, C.; Berdermann, J.; Jakowski, N.; Wilken, V.

2015-04-01

Since the last decades, the functioning of society depends more and more on well-functioning communication and navigation systems. As the availability and reliability of most of these satellite-based systems can be severely impacted by ionospheric storms, the accurate forecast of these events becomes a required task for mitigating social and economic risks. Here we aim to make initial steps toward an empirical model for ionospheric perturbations related to space weather events that are observable in the total electron content (TEC). The perturbation TEC forecast model will be a fast and robust approach, improving TEC forecasts based on climatological models during storm conditions. The derivation of such a model is a challenging task, because although a general dependence of the storm features (enhancement or depletion of electron density) on the storm onset time, local time, season and geomagnetic latitude is well known, there is a large deviation from the mean behavior. For a better understanding of storm conditions, this paper presents analyses of ionospheric storms observed in the TEC, broken down into diverse classes of storms. It provides a detailed characterization of the typical ionospheric storm behavior over Europe from high to midlatitudes, beyond case studies. Generally, the typical clear strong TEC enhancement starting in high latitudes and propagating equatorward is found to be strongest for storms starting in the morning hours independent of the season. In midlatitudes, it is strongest during noon. In addition, a clear difference between summer and winter storms is reported. While only winter storms develop high-latitude TEC enhancements, only summer storms typically exhibit TEC depletions during the storm recovery phase. During winter storms TEC enhancements can also occur the day following the storm onset, in contrast to summer storms. Strong correlation of TEC perturbation amplitudes to the Bz component of the interplanetary magnetic field and to a proxy of the polar cap potential are shown especially for summer midlatitude TEC enhancements during storms with and onset in the morning hours (6 to 12 UT over Europe) and for winter high-latitude TEC enhancements (around 60∘N). The results indicate the potential to derive improved predictions of maximum TEC deviations during space weather events, based on solar wind measurements.

Effects of dust storm events on weekly clinic visits related to pulmonary tuberculosis disease in Minqin, China

NASA Astrophysics Data System (ADS)

Wang, Yun; Wang, Ruoyu; Ming, Jing; Liu, Guangxiu; Chen, Tuo; Liu, Xinfeng; Liu, Haixia; Zhen, Yunhe; Cheng, Guodong

2016-02-01

Pulmonary tuberculosis (PTB) is a major public health problem in China. Minqin, a Northwest county of China, has a very high number of annual PTB clinic visits and it is also known for its severe dust storms. The epidemic usually begins in February and ends in July, while the dust storms mainly occur throughout spring and early summer, thereby suggesting that there might be a close link between the causative agent of PTB and dust storms. We investigated the general impact of dust storms on PTB over time by analyzing the variation in weekly clinic visits in Minqin during 2005-2012. We used the Mann-Whitney-Pettitt test and a regression model to determine the seasonal periodicity of PTB and dust storms in a time series, as well as assessing the relationships between meteorological variables and weekly PTB clinic visits. After comparing the number of weekly PTB cases in Gansu province with dust storm events, we detected a clear link between the population dynamics of PTB and climate events, i.e., the onset of epidemics and dust storms (defined by an atmospheric index) occurred in almost the same mean week. Thus, particulate matter might be the cause of PTB outbreaks on dust storm days. It is highly likely that the significant decline in annual clinic visits was closely associated with improvements in the local environment, which prevented desertification and decreased the frequency of dust storm events. To the best of our knowledge, this is the first population-based study to provide clear evidence that a PTB epidemic was affected by dust storms in China, which may give insights into the association between this environmental problem and the evolution of epidemic disease.

Method and apparatus for providing pulse pile-up correction in charge quantizing radiation detection systems

DOEpatents

Britton, Jr., Charles L.; Wintenberg, Alan L.

1993-01-01

A radiation detection method and system for continuously correcting the quantization of detected charge during pulse pile-up conditions. Charge pulses from a radiation detector responsive to the energy of detected radiation events are converted to voltage pulses of predetermined shape whose peak amplitudes are proportional to the quantity of charge of each corresponding detected event by means of a charge-sensitive preamplifier. These peak amplitudes are sampled and stored sequentially in accordance with their respective times of occurrence. Based on the stored peak amplitudes and times of occurrence, a correction factor is generated which represents the fraction of a previous pulses influence on a preceding pulse peak amplitude. This correction factor is subtracted from the following pulse amplitude in a summing amplifier whose output then represents the corrected charge quantity measurement.

Effects of detention on water quality of two stormwater detention ponds receiving highway surface runoff in Jacksonville, Florida

USGS Publications Warehouse

Hampson, P.S.

1986-01-01

Water and sediment samples were analyzed for major chemical constituents, nutrients, and heavy metals following ten storm events at two stormwater detention ponds that receive highway surface runoff in the Jacksonville, Florida, metropolitan area. The purpose of the sampling program was to detect changes in constituent concentration with time of detention within the pond system. Statistical inference of a relation with total rainfall was found in the initial concentrations of 11 constituents and with antecedent dry period for the initial concentrations of 3 constituents. Based on graphical examination and factor analysis , constituent behavior with time could be grouped into five relatively independent processes for one of the ponds. The processes were (1) interaction with shallow groundwater systems, (2) solubilization of bottom materials, (3) nutrient uptake, (4) seasonal changes in precipitation, and (5) sedimentation. Most of the observed water-quality changes in the ponds were virtually complete within 3 days following the storm event. (Author 's abstract)

Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

PubMed Central

Drews, Carl

2013-01-01

The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

Dependence of EMIC wave parameters during quiet, geomagnetic storm, and geomagnetic storm phase times

DOE PAGES

Halford, Alexa J.; Fraser, Brian J; Morley, Steven Karl; ...

2016-06-08

As electromagnetic ion cyclotron (EMIC) waves may play an important role in radiation belt dynamics, there has been a push to better include them into global simulations. How to best include EMIC wave effects is still an open question. Recently many studies have attempted to parameterize EMIC waves and their characteristics by geomagnetic indices. However, this does not fully take into account important physics related to the phase of a geomagnetic storm. In this paper we first consider how EMIC wave occurrence varies with the phase of a geomagnetic storm and the SYM-H, AE, and Kp indices. Here we showmore » that the storm phase plays an important role in the occurrence probability of EMIC waves. The occurrence rates for a given value of a geomagnetic index change based on the geomagnetic condition. Then in this study we also describe the typical plasma and wave parameters observed in L and magnetic local time for quiet, storm, and storm phase. These results are given in a tabular format in the supporting information so that more accurate statistics of EMIC wave parameters can be incorporated into modeling efforts.« less

Dependence of EMIC wave parameters during quiet, geomagnetic storm, and geomagnetic storm phase times

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

Halford, Alexa J.; Fraser, Brian J; Morley, Steven Karl

As electromagnetic ion cyclotron (EMIC) waves may play an important role in radiation belt dynamics, there has been a push to better include them into global simulations. How to best include EMIC wave effects is still an open question. Recently many studies have attempted to parameterize EMIC waves and their characteristics by geomagnetic indices. However, this does not fully take into account important physics related to the phase of a geomagnetic storm. In this paper we first consider how EMIC wave occurrence varies with the phase of a geomagnetic storm and the SYM-H, AE, and Kp indices. Here we showmore » that the storm phase plays an important role in the occurrence probability of EMIC waves. The occurrence rates for a given value of a geomagnetic index change based on the geomagnetic condition. Then in this study we also describe the typical plasma and wave parameters observed in L and magnetic local time for quiet, storm, and storm phase. These results are given in a tabular format in the supporting information so that more accurate statistics of EMIC wave parameters can be incorporated into modeling efforts.« less

Precipitation areal-reduction factor estimation using an annual-maxima centered approach

USGS Publications Warehouse

Asquith, W.H.; Famiglietti, J.S.

2000-01-01

The adjustment of precipitation depth of a point storm to an effective (mean) depth over a watershed is important for characterizing rainfall-runoff relations and for cost-effective designs of hydraulic structures when design storms are considered. A design storm is the precipitation point depth having a specified duration and frequency (recurrence interval). Effective depths are often computed by multiplying point depths by areal-reduction factors (ARF). ARF range from 0 to 1, vary according to storm characteristics, such as recurrence interval; and are a function of watershed characteristics, such as watershed size, shape, and geographic location. This paper presents a new approach for estimating ARF and includes applications for the 1-day design storm in Austin, Dallas, and Houston, Texas. The approach, termed 'annual-maxima centered,' specifically considers the distribution of concurrent precipitation surrounding an annual-precipitation maxima, which is a feature not seen in other approaches. The approach does not require the prior spatial averaging of precipitation, explicit determination of spatial correlation coefficients, nor explicit definition of a representative area of a particular storm in the analysis. The annual-maxima centered approach was designed to exploit the wide availability of dense precipitation gauge data in many regions of the world. The approach produces ARF that decrease more rapidly than those from TP-29. Furthermore, the ARF from the approach decay rapidly with increasing recurrence interval of the annual-precipitation maxima. (C) 2000 Elsevier Science B.V.The adjustment of precipitation depth of a point storm to an effective (mean) depth over a watershed is important for characterizing rainfall-runoff relations and for cost-effective designs of hydraulic structures when design storms are considered. A design storm is the precipitation point depth having a specified duration and frequency (recurrence interval). Effective depths are often computed by multiplying point depths by areal-reduction factors (ARF). ARF range from 0 to 1, vary according to storm characteristics, such as recurrence interval; and are a function of watershed characteristics, such as watershed size, shape, and geographic location. This paper presents a new approach for estimating ARF and includes applications for the 1-day design storm in Austin, Dallas, and Houston, Texas. The approach, termed 'annual-maxima centered,' specifically considers the distribution of concurrent precipitation surrounding an annual-precipitation maxima, which is a feature not seen in other approaches. The approach does not require the prior spatial averaging of precipitation, explicit determination of spatial correlation coefficients, nor explicit definition of a representative area of a particular storm in the analysis. The annual-maxima centered approach was designed to exploit the wide availability of dense precipitation gauge data in many regions of the world. The approach produces ARF that decrease more rapidly than those from TP-29. Furthermore, the ARF from the approach decay rapidly with increasing recurrence interval of the annual-precipitation maxima.

The Electric Storm of November 1882

NASA Astrophysics Data System (ADS)

Love, Jeffrey J.

2018-01-01

In November 1882, an intense magnetic storm related to a large sunspot group caused widespread interference to telegraph and telephone systems and provided spectacular and unusual auroral displays. The (ring current) storm time disturbance index for this storm reached maximum -Dst ≈ 386 nT, comparable to Halloween storm of 29-31 October 2003, but from 17 to 20 November the aa midlatitude geomagnetic disturbance index averaged 214.25 nT, the highest 4 day level of disturbance since the beginning of aa index in 1868. This storm contributed to scientists' understanding of the reality of solar-terrestrial interaction. Past occurrences of magnetic storms, like that of November 1882, can inform modern evaluations of the deleterious effects that a magnetic superstorm might have on technological systems of importance to society.

Simultaneous occurrence of diabetic ketoacidosis, thyroid storm, and multiple cerebral infarctions due to Moyamoya disease.

PubMed

Noh, Byoungho H; Cho, Sang-Won; Ahn, Sung Yeon

2016-02-01

Diabetic ketoacidosis (DKA) is one of the precipitating factors that can evoke a thyroid storm. Thyroid storm may cause cerebral ischemia in Moyamoya disease, which can coexist in patients with Graves' disease. A 16-year-old girl complaining of dizziness and palpitations visited the emergency department and was diagnosed with DKA combined with hyperthyroidism. A thyroid storm occurred 6 h after the start of DKA management. Her Burch and Wartofsky score was 65 points. Right hemiplegia developed during the thyroid storm, and brain magnetic resonance (MR) diffusion-weighted images revealed multiple acute infarcts in both hemispheres. MR angiography showed stenosis of both distal internal carotid arteries and both M1 portions of the middle cerebral arteries, consistent with Moyamoya disease. After acute management for the thyroid storm with methimazole, Lugol solution and hydrocortisone, the patient's neurological symptoms completely resolved within 1 month, and free T4 level normalized within 2 months. Thyroid storm may trigger cerebral ischemia in Moyamoya disease and lead to rapid progression of cerebrovascular occlusive disease. As a simultaneous occurrence of DKA, thyroid storm and cerebrovascular accident in Moyamoya disease highly elevates morbidity and mortality, prompt recognition and management are critical to save the patient's life.

The dichotomous response of flood and storm extremes to rising global temperatures

NASA Astrophysics Data System (ADS)

Sharma, A.; Wasko, C.

2017-12-01

Rising temperature have resulted in increases in short-duration rainfall extremes across the world. Additionally it has been shown (doi:10.1038/ngeo2456) that storms will intensify, causing derived flood peaks to rise even more. This leads us to speculate that flood peaks will increase as a result, complying with the storyline presented in past IPCC reports. This talk, however, shows that changes in flood extremes are much more complex. Using global data on extreme flow events, the study conclusively shows that while the very extreme floods may be rising as a result of storm intensification, the more frequent flood events are decreasing in magnitude. The study argues that changes in the magnitude of floods are a function of changes in storm patterns and as well as pre-storm or antecedent conditions. It goes on to show that while changes in storms dominate for the most extreme events and over smaller, more urbanised catchments, changes in pre-storm conditions are the driving factor in modulating flood peaks in large rural catchments. The study concludes by providing recommendations on how future flood design should proceed, arguing that current practices (or using a design storm to estimate floods) are flawed and need changing.

Equatorial ionospheric disturbances over the East African sector during the 2015 St. Patrick's day storm

NASA Astrophysics Data System (ADS)

Olwendo, O. J.; Cesaroni, C.; Yamazaki, Y.; Cilliers, P.

2017-10-01

During solar cycle 24, the St. Patrick's Day storm on 17 March, 2015 was one of the most severe geomagnetic storms. Several research investigations have been done and are still ongoing about this storm since the dynamics of this storm differs on a global scale from one sector to another. This study examines the response of the equatorial ionosphere to the storm in the East African sector. Total electron content (TEC) data from ground stations are used to investigate the evolution of the Equatorial Ionization Anomaly (EIA) during the storm. The TEC observations show a reduced EIA during 18-20 March 2015, consistent with previous studies at other longitudes. Analyses of ground magnetometer data and the thermospheric composition data from the NASA/TIMED satellite reveal that the reduced EIA during the storm can arise from the combined effect of the disturbance dynamo and composition change.

Integrated modeling of storm drain and natural channel networks for real-time flash flood forecasting in large urban areas

NASA Astrophysics Data System (ADS)

Habibi, H.; Norouzi, A.; Habib, A.; Seo, D. J.

2016-12-01

To produce accurate predictions of flooding in urban areas, it is necessary to model both natural channel and storm drain networks. While there exist many urban hydraulic models of varying sophistication, most of them are not practical for real-time application for large urban areas. On the other hand, most distributed hydrologic models developed for real-time applications lack the ability to explicitly simulate storm drains. In this work, we develop a storm drain model that can be coupled with distributed hydrologic models such as the National Weather Service Hydrology Laboratory's Distributed Hydrologic Model, for real-time flash flood prediction in large urban areas to improve prediction and to advance the understanding of integrated response of natural channels and storm drains to rainfall events of varying magnitude and spatiotemporal extent in urban catchments of varying sizes. The initial study area is the Johnson Creek Catchment (40.1 km2) in the City of Arlington, TX. For observed rainfall, the high-resolution (500 m, 1 min) precipitation data from the Dallas-Fort Worth Demonstration Network of the Collaborative Adaptive Sensing of the Atmosphere radars is used.

A soil water budget model for precipitation-induced shallow landslides

NASA Astrophysics Data System (ADS)

Yeh, Hsin-Fu; Lee, Cheng-Haw

2013-04-01

Precipitation infiltration influences both the quantity and quality of slope systems. Knowledge of the mechanisms leading to precipitation-induced slope failures is of great importance to the management of landslide hazard. In this study, a soil water balance model is developed to estimate soil water flux during the process of infiltration from rainfall data, with consideration of storm periods and non-storm periods. Two important assumptions in this study are given: (1) instantaneous uniform distribution of the degree of effective saturation and (2) a linear relationship between evapotranspiration and the related degree of saturation degree. For storm periods, the Brooks and Corey model estimates both the soil water retention curve (SWRC) and soil water parameters. The infiltration partition is employed by an infinite-series solution of Philip in conjunction with the time compression approximation (TCA). For none-storm periods, evapotranspiration can be derived for the moisture depletion of soil water. This study presents a procedure for calculating the safety factor for an unsaturated slope suffering from precipitation infiltration. The process of infiltration into a slope due to rainfall and its effect on soil slope behavior are examined using modified Mohr-Coulomb failure criterion in conjunction with a soil water balance model. The results indicate that the matric suction, which is closely related to slope stability, is affected by the effective degree of saturation controlled by rainfall events.

Impact of using scatterometer and altimeter data on storm surge forecasting

NASA Astrophysics Data System (ADS)

Bajo, Marco; De Biasio, Francesco; Umgiesser, Georg; Vignudelli, Stefano; Zecchetto, Stefano

2017-05-01

Satellite data are rarely used in storm surge models because of the lack of established methodologies. Nevertheless, they can provide useful information on surface wind and sea level, which can potentially improve the forecast. In this paper satellite wind data are used to correct the bias of wind originating from a global atmospheric model, while satellite sea level data are used to improve the initial conditions of the model simulations. In a first step, the capability of global winds (biased and unbiased) to adequately force a storm surge model are assessed against that of a high resolution local wind. Then, the added value of direct assimilation of satellite altimeter data in the storm surge model is tested. Eleven storm surge events, recorded in Venice from 2008 to 2012, are simulated using different configurations of wind forcing and altimeter data assimilation. Focusing on the maximum surge peak, results show that the relative error, averaged over the eleven cases considered, decreases from 13% to 7%, using both the unbiased wind and assimilating the altimeter data, while, if the high resolution local wind is used to force the hydrodynamic model, the altimeter data assimilation reduces the error from 9% to 6%. Yet, the overall capabilities in reproducing the surge in the first day of forecast, measured by the correlation and by the rms error, improve only with the use of the unbiased global wind and not with the use of high resolution local wind and altimeter data assimilation.

Turboprop+: enhanced Turboprop diffusion-weighted imaging with a new phase correction.

PubMed

Lee, Chu-Yu; Li, Zhiqiang; Pipe, James G; Debbins, Josef P

2013-08-01

Faster periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted imaging acquisitions, such as Turboprop and X-prop, remain subject to phase errors inherent to a gradient echo readout, which ultimately limits the applied turbo factor (number of gradient echoes between each pair of radiofrequency refocusing pulses) and, thus, scan time reductions. This study introduces a new phase correction to Turboprop, called Turboprop+. This technique employs calibration blades, which generate 2-D phase error maps and are rotated in accordance with the data blades, to correct phase errors arising from off-resonance and system imperfections. The results demonstrate that with a small increase in scan time for collecting calibration blades, Turboprop+ had a superior immunity to the off-resonance-related artifacts when compared to standard Turboprop and recently proposed X-prop with the high turbo factor (turbo factor = 7). Thus, low specific absorption rate and short scan time can be achieved in Turboprop+ using a high turbo factor, whereas off-resonance related artifacts are minimized. © 2012 Wiley Periodicals, Inc.

Improved scatterer property estimates from ultrasound backscatter for small gate lengths using a gate-edge correction factor

NASA Astrophysics Data System (ADS)

Oelze, Michael L.; O'Brien, William D.

2004-11-01

Backscattered rf signals used to construct conventional ultrasound B-mode images contain frequency-dependent information that can be examined through the backscattered power spectrum. The backscattered power spectrum is found by taking the magnitude squared of the Fourier transform of a gated time segment corresponding to a region in the scattering volume. When a time segment is gated, the edges of the gated regions change the frequency content of the backscattered power spectrum due to truncating of the waveform. Tapered windows, like the Hanning window, and longer gate lengths reduce the relative contribution of the gate-edge effects. A new gate-edge correction factor was developed that partially accounted for the edge effects. The gate-edge correction factor gave more accurate estimates of scatterer properties at small gate lengths compared to conventional windowing functions. The gate-edge correction factor gave estimates of scatterer properties within 5% of actual values at very small gate lengths (less than 5 spatial pulse lengths) in both simulations and from measurements on glass-bead phantoms. While the gate-edge correction factor gave higher accuracy of estimates at smaller gate lengths, the precision of estimates was not improved at small gate lengths over conventional windowing functions. .

Optimizing combined GPR, OSL and LiDAR (GOaL) to extract paleoenvironmental records and decipher shoreline evolution

NASA Astrophysics Data System (ADS)

Dougherty, A. J.; Choi, J. H.; Turney, C. S.; Dosseto, A.

2017-12-01

Records of past sea levels, storms, sediment supply and their impacts on the coastline are crucial for projecting likely shoreline changes resulting from anthropogenic warming. High-resolution geophysics, geochronology, and remote sensing techniques offer an optimal way to extract these records and decipher shoreline evolution. These methods include Light Detection and Ranging (LiDAR for imaging barrier morphologies in three dimensions), Ground Penetrating Radar (GPR for detecting paleo-dune, beach and nearshore stratigraphy) and Optically Stimulated Luminescence (OSL for dating deposition of sand grains along paleoshorelines). Each of these teqniques have been applied to coastal research over the decades since they were first introduced. Recently there has been a rapid increase their use since LiDAR became more available, GPR more user-friendly, and OSL more accessible. These methods have the potential to produce both detailed and voluminous datasets that can overwhelm or obscure significant features, such that discrepancies in analysis and/or presentation may lead to erroneous interpretations. In contrast, when utilized correctly on prograded barriers these methods (independently or in various combinations) have produced storm records, constructed sea-level curves, quantified sediment budgets, and deciphered coastal evolution. Therefore, combining the application of GPR, OSL, and LiDAR (GOaL) on one prograded barrier has the potential to generate detailed records of storms, sea level, and sediment supply for that coastline. Obtaining this GOaL hat-trick can provide valuable insights into how these three factors influenced past and future barrier evolution. Here we argue that systematically achieving GOaL hat-tricks on some of the 300+ prograded barriers worldwide would allow us to disentangle local patterns of sediment supply from regional effects of storms or global changes in sea level, allowing direct comparison to climate proxy records. To fully realize this aim requires standardization of methods to optimize results. The impetus for this initiative is to establish a framework for consistent data analysis that maximizes the potential of GOaL to contribute to climate change research and assist coastal communities in mitigating future impacts of global warming.

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

Borovsky, Joseph E; Cayton, Thomas E; Denton, Michael H

Electron flux measurements from 7 satellites in geosynchronous orbit from 1990-2007 are fit with relativistic bi-Maxwellians, yielding a number density n and temperature T description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value ofn is 3.7x10-4 cm-3 and the median value ofT is 142 keY. General statistical properties of n, T, and the 1.1-1.5 MeV flux J are investigated, including local-time and solar-cycle dependencies. Using superposed-epoch analysis triggered on storm onset, the evolution of the outer electron radiation belt through high-speed-steam-driven storms is investigated. The number density decay during the calm before themore » storm is seen, relativistic-electron dropouts and recoveries from dropout are investigated, and the heating of the outer electron radiation belt during storms is examined. Using four different triggers (SSCs, southward-IMF CME sheaths, southward-IMF magnetic clouds, and minimum Dst), CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms an absence of a density decay prior to storm onset is found, the compression of the outer electron radiation belt at time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase is seen, and the increase in density and temperature during storm recovery phase is observed. Differences are found between the density-temperature and the flux descriptions, with more information for analysis being available in the density-temperature description.« less

Storm surges and climate change implications for tidal marshes: Insight from the San Francisco Bay Estuary, California, USA

USGS Publications Warehouse

Thorne, Karen M.; Buffington, Kevin J.; Swanson, Kathleen; Takekawa, John Y.

2013-01-01

Tidal marshes are dynamic ecosystems, which are influenced by oceanic and freshwater processes and daily changes in sea level. Projected sea-level rise and changes in storm frequency and intensity will affect tidal marshes by altering suspended sediment supply, plant communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate if regional weather conditions resulting in low-pressure storms changed tidal conditions locally within three tidal marshes. We hypothesized that regional storms will increase sea level heights locally, resulting in increased inundation of the tidal marsh platform and plant communities. Using site-level measurements of elevation, plant communities, and water levels, we present results from two storm events in 2010 and 2011 from the San Francisco Bay Estuary (SFBE), California, USA. The January 2010 storm had the lowest recorded sea level pressure in the last 30 years for this region. During the storm episodes, the duration of tidal marsh inundation was 1.8 and 3.1 times greater than average for that time of year, respectively. At peak storm surges, over 65% in 2010 and 93% in 2011 of the plant community was under water. We also discuss the implications of these types of storms and projected sea-level rise on the structure and function of the tidal marshes and how that will impact the hydro-geomorphic processes and marsh biotic communities.

Quantitative Evaluation of Ionosphere Models for Reproducing Regional TEC During Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Shim, J. S.; Kuznetsova, M.; Rastaetter, L.; Bilitza, D.; Codrescu, M.; Coster, A. J.; Emery, B.; Foster, B.; Fuller-Rowell, T. J.; Goncharenko, L. P.; Huba, J.; Mitchell, C. N.; Ridley, A. J.; Fedrizzi, M.; Scherliess, L.; Schunk, R. W.; Sojka, J. J.; Zhu, L.

2015-12-01

TEC (Total Electron Content) is one of the key parameters in description of the ionospheric variability that has influence on the accuracy of navigation and communication systems. To assess current TEC modeling capability of ionospheric models during geomagnetic storms and to establish a baseline against which future improvement can be compared, we quantified the ionospheric models' performance by comparing modeled vertical TEC values with ground-based GPS TEC measurements and Multi-Instrument Data Analysis System (MIDAS) TEC. The comparison focused on North America and Europe sectors during selected two storm events: 2006 AGU storm (14-15 Dec. 2006) and 2013 March storm (17-19 Mar. 2013). The ionospheric models used for this study range from empirical to physics-based, and physics-based data assimilation models. We investigated spatial and temporal variations of TEC during the storms. In addition, we considered several parameters to quantify storm impacts on TEC: TEC changes compared to quiet time, rate of TEC change, and maximum increase/decrease during the storms. In this presentation, we focus on preliminary results of the comparison of the models performance in reproducing the storm-time TEC variations using the parameters and skill scores. This study has been supported by the Community Coordinated Modeling Center (CCMC) at the Goddard Space Flight Center. Model outputs and observational data used for the study will be permanently posted at the CCMC website (http://ccmc.gsfc.nasa.gov) for the space science communities to use.

Temperature and dust profiles in Martian dust storm conditions retrieved from Mars Climate Sounder measurements

NASA Astrophysics Data System (ADS)

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

2013-12-01

Mars Climate Sounder (MCS) is a mid- and far-infrared thermal emission radiometer on board the Mars Reconnaissance Orbiter. It measures radiances in limb and nadir/on-planet geometry from which vertical profiles of atmospheric temperature, water vapor, dust and condensates can be retrieved in an altitude range from 0 to 80 km and with a vertical resolution of ~5 km. Due to the limb geometry used as the MCS primary observation mode, retrievals in conditions with high aerosol loading are challenging. We have developed several modifications to the MCS retrieval algorithm that will facilitate profile retrievals in high-dust conditions. Key modifications include a retrieval option that uses a surface pressure climatology if a pressure retrieval is not possible in high dust conditions, an extension of aerosol retrievals to higher altitudes, and a correction to the surface temperature climatology. In conditions of a global dust storm, surface temperatures tend to be lower compared to standard conditions. Taking this into account using an adaptive value based on atmospheric opacity leads to improved fits to the radiances measured by MCS and improves the retrieval success rate. We present first results of these improved retrievals during the global dust storm in 2007. Based on the limb opacities observed during the storm, retrievals are typically possible above ~30 km altitude. Temperatures around 240 K are observed in the middle atmosphere at mid- and high southern latitudes after the onset of the storm. Dust appears to be nearly homogeneously mixed at lower altitudes. Significant dust opacities are detected at least up to 70 km altitude. During much of the storm, in particular at higher altitudes, the retrieved dust profiles closely resemble a Conrath-profile.

Low-grazing angle laser scans of foreshore topography, swash and inner surf-zone wave heights, and mean water level: validation and storm response

NASA Astrophysics Data System (ADS)

Brodie, K. L.; McNinch, J. E.; Forte, M.; Slocum, R.

2010-12-01

Accurately predicting beach evolution during storms requires models that correctly parameterize wave runup and inner surf-zone processes, the principle drivers of sediment exchange between the beach and surf-zone. Previous studies that aimed at measuring wave runup and swash zone water levels have been restricted to analyzing water-elevation time series of (1) the shoreward-most swash excursion using video imaging or near-bed resistance wires, or (2) the free water surface at a particular location on the foreshore using pressure sensors. These data are often compared with wave forcing parameters in deeper water as well as with beach topography observed at finite intervals throughout the time series to identify links between foreshore evolution, wave spectra, and water level variations. These approaches have lead to numerous parameterizations and empirical equations for wave runup but have difficulty providing adequate data to quantify and understand short-term spatial and temporal variations in foreshore evolution. As a result, modeling shoreline response and changes in sub-aerial beach volume during storms remains a substantial challenge. Here, we demonstrate a novel technique in which a terrestrial laser scanner is used to continuously measure beach and foreshore topography as well as water elevation (and wave height) in the swash and inner surf-zone during storms. The terrestrial laser scanner is mounted 2-m above the dune crest at the Field Research Facility in Duck, NC in line with cross-shore wave gauges located at 2-m, 3-m, 5-m, 6-m, and 8-m of water depth. The laser is automated to collect hourly, two-dimensional, 20-minute time series of data along a narrow swath in addition to an hourly three-dimensional laser scan of beach and dune topography +/- 250m alongshore from the laser. Low grazing-angle laser scans are found to reflect off of the surface of the water, providing spatially (e.g. dx <= 0.1 m) and temporally (e.g. dt = 3Hz) dense elevation data of the foreshore, swash, and inner-surf zone bore heights. Foreshore elevation precision is observed to be < 0.01m. Sea surface elevation data is confined to the breaking region and is more extensive in rough, fully-dissipative surf zones, with the fronts of breaking waves and dissipated bores resolved most clearly. Time series of swash front (runup) data will be compared with simultaneously collected video-imaged swash timestacks, and wave height data of the inner surf zone will be compared with wave data from an aquadopp in 2m of water depth. In addition, analysis of the water level time series data at 10 cm intervals across the profile enables reconstruction of the shoreline setup profile as well as cross-shore variations in 1D wave spectra. Foreshore beach morphology evolution is analyzed using both the 2D cross-shore profile data, as well as the 3D topographic data during multiple storm events. Potential sources of error in the measurements, such as shadowing of the wave troughs or reflectance off of wave spray is identified and quantified.

A Conceptual Model of the Severe-Storm Environment for Inclusion into Air Weather Service Severe-Storm Analysis and Forecast Procedures.

DTIC Science & Technology

1984-11-16

thunderstorm forecasting , Bull. Am. Meteorol. Soc. 34:250-252. 19. Galway , J.G. (1956) The lifted index as a prediction of latent instability, Bull...downwind, which are geographically related and can be traced through time by a forecaster . In fact, a typical Great Plains severe-storm situation has...weather station setting, only one sounding can be plotted and anal- yzed because of time constraints. Appendix C contains two single-station forecast

Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

NASA Astrophysics Data System (ADS)

Goslin, Jérôme; Clemmensen, Lars B.

2017-10-01

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

Seasonal timing of first rain storms affects rare plant population dynamics

USGS Publications Warehouse

Levine, J.M.; McEachern, A.K.; Cowan, C.

2011-01-01

A major challenge in forecasting the ecological consequences of climate change is understanding the relative importance of changes to mean conditions vs. changes to discrete climatic events, such as storms, frosts, or droughts. Here we show that the first major storm of the growing season strongly influences the population dynamics of three rare and endangered annual plant species in a coastal California (USA) ecosystem. In a field experiment we used moisture barriers and water addition to manipulate the timing and temperature associated with first major rains of the season. The three focal species showed two- to fivefold variation in per capita population growth rates between the different storm treatments, comparable to variation found in a prior experiment imposing eightfold differences in season-long precipitation. Variation in germination was a major demographic driver of how two of three species responded to the first rains. For one of these species, the timing of the storm was the most critical determinant of its germination, while the other showed enhanced germination with colder storm temperatures. The role of temperature was further supported by laboratory trials showing enhanced germination in cooler treatments. Our work suggests that, because of species-specific cues for demographic transitions such as germination, changes to discrete climate events may be as, if not more, important than changes to season-long variables.

Van Allen Probes observations of outer radiation belt evolution during CME and CIR storms

NASA Astrophysics Data System (ADS)

Hudson, M. K.; Shen, X.; Jaynes, A. N.; Shi, Q.; Tian, A.; Claudepierre, S. G.; Qin, M.; Zong, Q.; Sun, W.

2017-12-01

Storm time outer radiation belt evolutes dramatically. It is still an stuff problem to model and predict the evolutions. The MeV electron flux can loss, no change or increase during different storms. Most of the previous statistical results were made by low altitude polar orbiting satellites, such as SAMPEX and NOAA POES, or geosynchronous orbiting satellites, such as GOES. Although part of the electron flux observed by polar orbiting satellites can be treated as trapped electrons, they are already close to the ionosphere with pitch angles apart from 90 degrees. Geosynchronous orbiting satellites are limited to r=6.6 RE (geocentric radial distance in Earth radii). The Van Allen Probes twin spacecraft, launched on 30 August 2012 with orbit near the equatorial plane, apogee at 5.8 RE and perigee at 620 km, give us a good oppurtuinity to study the storm-time outer radiation belt evolutions. During the time period from the begining of 2013 to the end of 2016, 31 CMEs and 28 CIRs are identified from OMNI-2 dataset. Superposed epoch analysis shows that CIR-storms which increased flux closer to geosynchronous orbit consistent with earlier studies, while CME-storms likely produce deeper penetration of enhanced flux and local heating which is greater at higher energies at lower L*.

Seasonal timing of first rain storms affects rare plant population dynamics.

PubMed

Levine, Jonathan M; McEachern, A Kathryn; Cowan, Clark

2011-12-01

A major challenge in forecasting the ecological consequences of climate change is understanding the relative importance of changes to mean conditions vs. changes to discrete climatic events, such as storms, frosts, or droughts. Here we show that the first major storm of the growing season strongly influences the population dynamics of three rare and endangered annual plant species in a coastal California (USA) ecosystem. In a field experiment we used moisture barriers and water addition to manipulate the timing and temperature associated with first major rains of the season. The three focal species showed two- to fivefold variation in per capita population growth rates between the different storm treatments, comparable to variation found in a prior experiment imposing eightfold differences in season-long precipitation. Variation in germination was a major demographic driver of how two of three species responded to the first rains. For one of these species, the timing of the storm was the most critical determinant of its germination, while the other showed enhanced germination with colder storm temperatures. The role of temperature was further supported by laboratory trials showing enhanced germination in cooler treatments. Our work suggests that, because of species-specific cues for demographic transitions such as germination, changes to discrete climate events may be as, if not more, important than changes to season-long variables.

Prenatal maternal stress predicts autism traits in 6½ year-old children: Project Ice Storm.

PubMed

Walder, Deborah J; Laplante, David P; Sousa-Pires, Alexandra; Veru, Franz; Brunet, Alain; King, Suzanne

2014-10-30

Research implicates prenatal maternal stress (PNMS) as a risk factor for neurodevelopmental disorders; however few studies report PNMS effects on autism risk in offspring. We examined, prospectively, the degree to which objective and subjective elements of PNMS explained variance in autism-like traits among offspring, and tested moderating effects of sex and PNMS timing in utero. Subjects were 89 (46F/43M) children who were in utero during the 1998 Quebec Ice Storm. Soon after the storm, mothers completed questionnaires on objective exposure and subjective distress, and completed the Autism Spectrum Screening Questionnaire (ASSQ) for their children at age 6½. ASSQ scores were higher among boys than girls. Greater objective and subjective PNMS predicted higher ASSQ independent of potential confounds. An objective-by-subjective interaction suggested that when subjective PNMS was high, objective PNMS had little effect; whereas when subjective PNMS was low, objective PNMS strongly affected ASSQ scores. A timing-by-objective stress interaction suggested objective stress significantly affected ASSQ in first-trimester exposed children, though less so with later exposure. The final regression explained 43% of variance in ASSQ scores; the main effect of sex and the sex-by-PNMS interactions were not significant. Findings may help elucidate neurodevelopmental origins of non-clinical autism-like traits from a dimensional perspective. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

The Role of Ionospheric Outflow Preconditioning in Determining Storm Geoeffectiveness

NASA Astrophysics Data System (ADS)

Welling, D. T.; Liemohn, M. W.; Ridley, A. J.

2012-12-01

It is now well accepted that ionospheric outflow plays an important role in the development of the plasma sheet and ring current during geomagnetic storms. Furthermore, even during quiet times, ionospheric plasma populates the magnetospheric lobes, producing a reservoir of hydrogen and oxygen ions. When the Interplanetary Magnetic Field (IMF) turns southward, this reservoir is connected to the plasma sheet and ring current through magnetospheric convection. Hence, the conditions of the ionosphere and magnetospheric lobes leading up to magnetospheric storm onset have important implications for storm development. Despite this, there has been little research on this preconditioning; most global simulations begin just before storm onset, neglecting preconditioning altogether. This work explores the role of preconditioning in determining the geoeffectiveness of storms using a coupled global model system. A model of ionospheric outflow (the Polar Wind Outflow Model, PWOM) is two-way coupled to a global magnetohydrodynamic model (the Block-Adaptive Tree Solar wind Roe-type Upwind Scheme, BATS-R-US), which in turn drives a ring current model (the Ring current Atmosphere interactions Model, RAM). This unique setup is used to simulate an idealized storm. The model is started at many different times, from 1 hour before storm onset to 12 hours before. The effects of storm preconditioning are examined by investigating the total ionospheric plasma content in the lobes just before onset, the total ionospheric contribution in the ring current just after onset, and the effects on Dst, magnetic elevation angle at geosynchronous, and total ring current energy density. This experiment is repeated for different solar activity levels as set by F10.7 flux. Finally, a synthetic double-dip storm is constructed to see how two closely spaced storms affect each other by changing the preconditioning environment. It is found that preconditioning of the magnetospheric lobes via ionospheric outflow greatly influences the geoeffectiveness of magnetospheric storms.

Climate Change Increases Reproductive Failure in Magellanic Penguins

PubMed Central

Boersma, P. Dee; Rebstock, Ginger A.

2014-01-01

Climate change is causing more frequent and intense storms, and climate models predict this trend will continue, potentially affecting wildlife populations. Since 1960 the number of days with >20 mm of rain increased near Punta Tombo, Argentina. Between 1983 and 2010 we followed 3496 known-age Magellanic penguin (Spheniscus magellanicus) chicks at Punta Tombo to determine how weather impacted their survival. In two years, rain was the most common cause of death killing 50% and 43% of chicks. In 26 years starvation killed the most chicks. Starvation and predation were present in all years. Chicks died in storms in 13 of 28 years and in 16 of 233 storms. Storm mortality was additive; there was no relationship between the number of chicks killed in storms and the numbers that starved (P = 0.75) or that were eaten (P = 0.39). However, when more chicks died in storms, fewer chicks fledged (P = 0.05, R 2 = 0.14). More chicks died when rainfall was higher and air temperature lower. Most chicks died from storms when they were 9–23 days old; the oldest chick killed in a storm was 41 days old. Storms with heavier rainfall killed older chicks as well as more chicks. Chicks up to 70 days old were killed by heat. Burrow nests mitigated storm mortality (N = 1063). The age span of chicks in the colony at any given time increased because the synchrony of egg laying decreased since 1983, lengthening the time when chicks are vulnerable to storms. Climate change that increases the frequency and intensity of storms results in more reproductive failure of Magellanic penguins, a pattern likely to apply to many species breeding in the region. Climate variability has already lowered reproductive success of Magellanic penguins and is likely undermining the resilience of many other species. PMID:24489663

On the log-normality of historical magnetic-storm intensity statistics: implications for extreme-event probabilities

USGS Publications Warehouse

Love, Jeffrey J.; Rigler, E. Joshua; Pulkkinen, Antti; Riley, Pete

2015-01-01

An examination is made of the hypothesis that the statistics of magnetic-storm-maximum intensities are the realization of a log-normal stochastic process. Weighted least-squares and maximum-likelihood methods are used to fit log-normal functions to −Dst storm-time maxima for years 1957-2012; bootstrap analysis is used to established confidence limits on forecasts. Both methods provide fits that are reasonably consistent with the data; both methods also provide fits that are superior to those that can be made with a power-law function. In general, the maximum-likelihood method provides forecasts having tighter confidence intervals than those provided by weighted least-squares. From extrapolation of maximum-likelihood fits: a magnetic storm with intensity exceeding that of the 1859 Carrington event, −Dst≥850 nT, occurs about 1.13 times per century and a wide 95% confidence interval of [0.42,2.41] times per century; a 100-yr magnetic storm is identified as having a −Dst≥880 nT (greater than Carrington) but a wide 95% confidence interval of [490,1187] nT.

Observatory geoelectric fields induced in a two-layer lithosphere during magnetic storms

USGS Publications Warehouse

Love, Jeffrey J.; Swidinsky, Andrei

2015-01-01

We report on the development and validation of an algorithm for estimating geoelectric fields induced in the lithosphere beneath an observatory during a magnetic storm. To accommodate induction in three-dimensional lithospheric electrical conductivity, we analyze a simple nine-parameter model: two horizontal layers, each with uniform electrical conductivity properties given by independent distortion tensors. With Laplace transformation of the induction equations into the complex frequency domain, we obtain a transfer function describing induction of observatory geoelectric fields having frequency-dependent polarization. Upon inverse transformation back to the time domain, the convolution of the corresponding impulse-response function with a geomagnetic time series yields an estimated geoelectric time series. We obtain an optimized set of conductivity parameters using 1-s resolution geomagnetic and geoelectric field data collected at the Kakioka, Japan, observatory for five different intense magnetic storms, including the October 2003 Halloween storm; our estimated geoelectric field accounts for 93% of that measured during the Halloween storm. This work demonstrates the need for detailed modeling of the Earth’s lithospheric conductivity structure and the utility of co-located geomagnetic and geoelectric monitoring.

A novel approach to the dynamical complexity of the Earth's magnetosphere at geomagnetic storm time-scales based on recurrences

NASA Astrophysics Data System (ADS)

Donner, Reik; Balasis, Georgios; Stolbova, Veronika; Wiedermann, Marc; Georgiou, Marina; Kurths, Jürgen

2016-04-01

Magnetic storms are the most prominent global manifestations of out-of-equilibrium magnetospheric dynamics. Investigating the dynamical complexity exhibited by geomagnetic observables can provide valuable insights into relevant physical processes as well as temporal scales associated with this phenomenon. In this work, we introduce several innovative data analysis techniques enabling a quantitative analysis of the Dst index non-stationary behavior. Using recurrence quantification analysis (RQA) and recurrence network analysis (RNA), we obtain a variety of complexity measures serving as markers of quiet- and storm-time magnetospheric dynamics. We additionally apply these techniques to the main driver of Dst index variations, the V BSouth coupling function and interplanetary medium parameters Bz and Pdyn in order to discriminate internal processes from the magnetosphere's response directly induced by the external forcing by the solar wind. The derived recurrence-based measures allow us to improve the accuracy with which magnetospheric storms can be classified based on ground-based observations. The new methodology presented here could be of significant interest for the space weather research community working on time series analysis for magnetic storm forecasts.

Mapping Infected Area after a Flash-Flooding Storm Using Multi Criteria Analysis and Spectral Indices

NASA Astrophysics Data System (ADS)

Al-Akad, S.; Akensous, Y.; Hakdaoui, M.

2017-11-01

This research article is summarize the applications of remote sensing and GIS to study the urban floods risk in Al Mukalla. Satellite acquisition of a flood event on October 2015 in Al Mukalla (Yemen) by using flood risk mapping techniques illustrate the potential risk present in this city. Satellite images (The Landsat and DEM images data were atmospherically corrected, radiometric corrected, and geometric and topographic distortions rectified.) are used for flood risk mapping to afford a hazard (vulnerability) map. This map is provided by applying image-processing techniques and using geographic information system (GIS) environment also the application of NDVI, NDWI index, and a method to estimate the flood-hazard areas. Four factors were considered in order to estimate the spatial distribution of the hazardous areas: flow accumulation, slope, land use, geology and elevation. The multi-criteria analysis, allowing to deal with vulnerability to flooding, as well as mapping areas at the risk of flooding of the city Al Mukalla. The main object of this research is to provide a simple and rapid method to reduce and manage the risks caused by flood in Yemen by take as example the city of Al Mukalla.

Curcumin suppression of cytokine release and cytokine storm. A potential therapy for patients with Ebola and other severe viral infections.

PubMed

Sordillo, Peter P; Helson, Lawrence

2015-01-01

The terminal stage of Ebola and other viral diseases is often the onset of a cytokine storm, the massive overproduction of cytokines by the body's immune system. The actions of curcumin in suppressing cytokine release and cytokine storm are discussed. Curcumin blocks cytokine release, most importantly the key pro-inflammatory cytokines, interleukin-1, interleukin-6 and tumor necrosis factor-α. The suppression of cytokine release by curcumin correlates with clinical improvement in experimental models of disease conditions where a cytokine storm plays a significant role in mortality. The use of curcumin should be investigated in patients with Ebola and cytokine storm. Intravenous formulations may allow achievement of therapeutic blood levels of curcumin. Copyright © 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

N : P stoichiometry in a forested runoff during storm events: comparisons with regions and vegetation types.

PubMed

Guo, Lanlan; Chen, Yi; Zhang, Zhao; Fukushima, Takehiko

2012-01-01

Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo.

N : P Stoichiometry in a Forested Runoff during Storm Events: Comparisons with Regions and Vegetation Types

PubMed Central

Guo, Lanlan; Chen, Yi; Zhang, Zhao; Fukushima, Takehiko

2012-01-01

Nitrogen and phosphorus are considered the most important limiting elements in terrestrial and aquatic ecosystems. however, very few studies have focused on which is from forested streams, a bridge between these two systems. To fill this gap, we examined the concentrations of dissolved N and P in storm waters from forested watersheds of five regions in Japan, to characterize nutrient limitation and its potential controlling factors. First, dissolved N and P concentrations and the N : P ratio on forested streams were higher during storm events relative to baseflow conditions. Second, significantly higher dissolved inorganic N concentrations were found in storm waters from evergreen coniferous forest streams than those from deciduous broadleaf forest streams in Aichi, Kochi, Mie, Nagano, and with the exception of Tokyo. Finally, almost all the N : P ratios in the storm water were generally higher than 34, implying that the storm water should be P-limited, especially for Tokyo. PMID:22547978

Long-term geomagnetically induced current observations in New Zealand: Earth return corrections and geomagnetic field driver

NASA Astrophysics Data System (ADS)

Mac Manus, Daniel H.; Rodger, Craig J.; Dalzell, Michael; Thomson, Alan W. P.; Clilverd, Mark A.; Petersen, Tanja; Wolf, Moritz M.; Thomson, Neil R.; Divett, Tim

2017-08-01

Transpower New Zealand Limited has measured DC currents in transformer neutrals in the New Zealand electrical network at multiple South Island locations. Near-continuous archived DC current data exist since 2001, starting with 12 different substations and expanding from 2009 to include 17 substations. From 2001 to 2015 up to 58 individual transformers were simultaneously monitored. Primarily, the measurements were intended to monitor the impact of the high-voltage DC system linking the North and South Islands when it is operating in "Earth return" mode. However, after correcting for Earth return operation, as described here, the New Zealand measurements provide an unusually long and spatially detailed set of geomagnetically induced current (GIC) measurements. We examine the peak GIC magnitudes observed from these observations during two large geomagnetic storms on 6 November 2001 and 2 October 2013. Currents of 30-50 A are observed, depending on the measurement location. There are large spatial variations in the GIC observations over comparatively small distances, which likely depend upon network layout and ground conductivity. We then go on to examine the GIC in transformers throughout the South Island during more than 151 h of geomagnetic storm conditions. We compare the GIC to the various magnitude and rate of change components of the magnetic field. Our results show that there is a strong correlation between the magnitude of the GIC and the rate of change of the horizontal magnetic field (H'). This correlation is particularly clear for transformers that show large GIC current during magnetic storms.

Assimilation of attenuated data from X-band network radars using ensemble Kalman filter

NASA Astrophysics Data System (ADS)

Cheng, Jing

To use reflectivity data from X-band radars for quantitative precipitation estimation and storm-scale data assimilation, the effect of attenuation must be properly accounted for. Traditional approaches try to make correction to the attenuated reflectivity first before using the data. An alternative, theoretically more attractive approach builds the attenuation effect into the reflectivity observation operator of a data assimilation system, such as an ensemble Kalman filter (EnKF), allowing direct assimilation of the attenuated reflectivity and taking advantage of microphysical state estimation using EnKF methods for a potentially more accurate solution. This study first tests the approach for the CASA (Center for Collaborative Adaptive Sensing of the Atmosphere) X-band radar network configuration through observing system simulation experiments (OSSE) for a quasi-linear convective system (QLCS) that has more significant attenuation than isolated storms. To avoid the problem of potentially giving too much weight to fully attenuated reflectivity, an analytical, echo-intensity-dependent model for the observation error (AEM) is developed and is found to improve the performance of the filter. By building the attenuation into the forward observation operator and combining it with the application of AEM, the assimilation of attenuated CASA observations is able to produce a reasonably accurate analysis of the QLCS inside CASA radar network coverage. Compared with foregoing assimilation of radar data with weak radar reflectivity or assimilating only radial velocity data, our method can suppress the growth of spurious echoes while obtaining a more accurate analysis in the terms of root-mean-square (RMS) error. Sensitivity experiments are designed to examine the effectiveness of AEM by introducing multiple sources of observation errors into the simulated observations. The performance of such an approach in the presence of resolution-induced model error is also evaluated and good results are obtained. The same EnKF framework with attenuation correction is used to test different possible configurations of 2 hypothetical radars added to the existing network of 4 CASA radars through OSSEs. Though plans to expand the CASA radar network did not materialize, such experiments can provide guidance in the site selection of future X-band or other short-wavelength radar networks, as well as examining the benefit of X-band radar networks that consist of a much larger number of radars. Two QLCSs with different propagation speeds are generated and serve as the truth for our OSSEs. Assimilation and forecast results are compared among the OSSEs, assimilating only X-band or short-wavelength radar data. Overall, radar networks with larger downstream spatial coverage tend to provide overall the best analyses and 1-hour forecasts. The best analyses and forecasts of convective scale structure, however, are obtained when Dual- or Multi-Doppler coverage is preferred, even at the expense of minor loss in spatial coverage. Built-in attenuation correction is then applied, for the first time, to a real case (the 24 May 2011 tornadic storm near Chickasha, Oklahoma), using data from the X-band CASA radars. The attenuation correction procedure is found to be very effective---the analyses obtained using attenuated data are better than those obtained using pre-corrected data when all the values of reflectivity observations are assimilated. The effectiveness of the procedure is further examined by comparing the deterministic and ensemble forecasts started from the analysis of each experiment. The deterministic forecast experiment results indicate that assimilating un-corrected observations directly actually retains some information that might be lost in the pre-corrected CASA observations by forecasting a longer-lasting trailing line, similar to that observed in WSR-88D data. In the ensemble forecasts, assimilating un-corrected observations directly, using our attenuation-correcting EnKF, results in a forecast with a more intense tornado track than the experiment that assimilates all values of pre-corrected CASA data. This work is the first to assimilate attenuated observations from a radar network in OSSEs, as well as the first attempt to directly assimilate real, uncorrected CASA data into a numerical weather prediction (NWP) model using EnKF.

Global Ionosphere Perturbations Monitored by the Worldwide GPS Network

NASA Technical Reports Server (NTRS)

Ho, C. M.; Manucci, A. T.; Lindqwister, U. J.; Pi, X.

1996-01-01

For the first time, measurements from the Global Positioning System (GPS) worldwide network are employed to study the global ionospheric total electron content(TEC) changes during a magnetic storm (November 26, 1994). These measurements are obtained from more than 60 world-wide GPS stations which continuously receive dual-frequency signals. Based on the delays of the signals, we have generated high resolution global ionospheric maps (GIM) of TEC at 15 minute intervals. Using a differential method comparing storm time maps with quiet time maps, we find that significant TEC increases (the positive effect ) are the major feature in the winter hemisphere during this storm (the maximum percent change relative to quiet times is about 150 percent).

Deep convection over Northern Italy: synoptic and thermodynamic analysis

NASA Astrophysics Data System (ADS)

Costa, S.; Mezzasalma, P.; Levizzani, V.; Alberoni, P. P.; Nanni, S.

Synoptic and thermodynamic characteristics of severe storm outbreaks, including supercells, over northern Italy's Po valley are examined over a 3-year period. Storms are divided into three main categories according to the most relevant associated ground phenomenon: tornado-like, hailfall and heavy rain. For each category, the most common synoptic characteristics are investigated. Sounding data are used to calculate stability indices that help define the storm's environment. Results indicate that the interaction between the synoptic flow and the steep Alpine orography is the key factor responsible for building up the mesoscale circulation that leads to different kinds of severe storms. Some of the stability indices can be regarded as predictors of intense convection.

Earlier vegetation green-up has reduced spring dust storms.

PubMed

Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

2014-10-24

The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p < 0.01) between green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = -0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world.

The electric storm of November 1882

USGS Publications Warehouse

Love, Jeffrey J.

2018-01-01

In November 1882, an intense magnetic storm related to a large sunspot group caused widespread interference to telegraph and telephone systems and provided spectacular and unusual auroral displays. The (ring current) storm time disturbance index for this storm reached maximum −Dst ≈ 386 nT, comparable to Halloween storm of 29–31 October 2003, but from 17 to 20 November the aa midlatitude geomagnetic disturbance index averaged 214.25 nT, the highest 4 day level of disturbance since the beginning of aa index in 1868. This storm contributed to scientists' understanding of the reality of solar‐terrestrial interaction. Past occurrences of magnetic storms, like that of November 1882, can inform modern evaluations of the deleterious effects that a magnetic superstorm might have on technological systems of importance to society.

Climate Driven Life Histories: The Case of the Mediterranean Storm Petrel

PubMed Central

Soldatini, Cecilia; Albores-Barajas, Yuri Vladimir; Massa, Bruno; Gimenez, Olivier

2014-01-01

Seabirds are affected by changes in the marine ecosystem. The influence of climatic factors on marine food webs can be reflected in long-term seabird population changes. We modelled the survival and recruitment of the Mediterranean storm petrel (Hydrobates pelagicus melitensis) using a 21-year mark-recapture dataset involving almost 5000 birds. We demonstrated a strong influence of prebreeding climatic conditions on recruitment age and of rainfall and breeding period conditions on juvenile survival. The results suggest that the juvenile survival rate of the Mediterranean subspecies may not be negatively affected by the predicted features of climate change, i.e., warmer summers and lower rainfall. Based on considerations of winter conditions in different parts of the Mediterranean, we were able to draw inferences about the wintering areas of the species for the first time. PMID:24728099

Pathogen and nutrient pulsing and attenuation in "accidental" urban wetland networks along the Salt River in Phoenix, AZ

NASA Astrophysics Data System (ADS)

Palta, M. M.; Grimm, N. B.

2013-12-01

Increases in available nutrients and bacteria in urban streams are at the forefront of research concerns within the ecological and medical communities, and both pollutants are expected to become more problematic under projected changes in climate. Season, discharge, instream conditions (oxygen, water velocity), and weather conditions (antecedent moisture) all may influence loading rates to and the retention capabilities of wetlands fed by urban runoff and storm flow. The aim of this research was to examine the effect of these variables on nutrient (nitrogen, phosphorus) and Escherichia coli (E. coli) loading and attenuation along flow paths in urban wetland networks along the Salt River in Phoenix, AZ. Samples were collected for one year along flowpaths through wetlands that formed below six perennially flowing outfalls. Collection took place monthly during baseflow (dry season) conditions, and before and immediately following storm events, in the summer monsoon and winter rainy seasons. Water quality was assessed at the following points: immediately downstream of the outfall, mid-wetland, and downstream of the wetland. For determination of E. coli counts, samples were plated on coliform-selective media (Chromocult) and incubated for 24 hours. Plates were then used to enumerate E. coli. For determination of nutrient concentrations, samples were filtered and frozen until they could be analyzed by ion chromatography and automated wet chemistry. During both summer and winter, total discharge into the wetlands increased during storm events. Concentrations of PO43+, NH4+, and E. coli were significantly higher following storm events than during baseflow conditions, and post-storm peaks in concentration ('pulses') were higher during the summer monsoon than in winter storms. Pulses of pollutants during storms were highest when preceded by hot, dry conditions. NO3- was high in both base and stormflow. E. coli counts and nutrient concentrations dropped along flowpaths through the wetlands, indicating high attenuation capability even during storms. Attenuation of nutrients during baseflow appeared to be a function of microbial processing, while during stormflow, when water retention time in the wetlands was reduced, attenuation was likely explained by other factors, such as sediment adsorption. Potential tradeoffs emerged between removal of NO3- (highest under low dissolved oxygen) and E. coli (highest under high dissolved oxygen) during baseflow. Climate change models project increases in severe droughts and extreme precipitation events for the southwestern United States, which can lead to more sewage leakages and increases in contaminated runoff from impervious surfaces in urban areas. Wetlands are constructed or restored to mitigate microbial contamination of wastewater. Our research indicates that even "accidental" urban wetlands can serve to reduce downstream transport of nutrients and pathogens in storm and wastewater. However, wetland restoration or design targeting increased water retention time may increase the capability of accidental wetlands in this urban desert river channel to remove nutrients and pathogens from stormwater.

Short- and medium-term response to storms on three Mediterranean coarse-grained beaches

NASA Astrophysics Data System (ADS)

Grottoli, Edoardo; Bertoni, Duccio; Ciavola, Paolo

2017-10-01

The storm response of three Italian coarse-grained beaches was investigated to better understand the morphodynamics of coarse-clastic beaches in a microtidal context. Two of the studied sites are located on the eastern side of the country (Portonovo and Sirolo) and the third one (Marina di Pisa) is on the western side. Portonovo and Sirolo are mixed sand and gravel beaches where the storms approach from two main directions, SE and NE. Marina di Pisa is a coarse-grained, gravel-dominated beach, exposed to storms driven by SW winds. Gravel nourishments were undertaken in recent years on the three sites. Beach topography was monitored measuring the same network of cross sections at a monthly (i.e. short-term) to seasonal frequency (i.e. medium-term). Geomorphic changes were examined before and after storm occurrences by means of profile analyses and shoreline position evaluations. The beach orientation and the influence of hard structures are the main factors controlling the transport and accumulation of significant amount of sediments and the consequent high variability of beach morphology over the medium-term. For Marina di Pisa, storms tend to accumulate material towards the upper part of the beach with no shoreline rotation and no chance to recover the initial configuration. Sirolo and Portonovo showed a similar behaviour that is more typical of pocket beaches. Both beaches show shoreline rotation after storms in a clockwise or counter-clockwise direction according to the incoming wave direction. The wider and longer beach at Sirolo allows the accumulation of a thin layer of sediment during storms, rather than at Portonovo where, given its longshore and landward boundaries, the beach material tends to accumulate in greater thickness. After storms, Sirolo and especially Portonovo can quickly recover the initial beach configuration, as soon as another storm of comparable energy approaches from the opposite direction of the previous one. Large morphological variations after the storm on mixed sand and gravel beaches do not necessarily mean a slower recovery of surface topography and shoreline position. Considering that all the three beaches were recently nourished with gravel, it emerged that the differences between the nourishment and the native material, in terms of size and composition, seem to have an important influence on the dynamics of the sediment stock. Considering that recent studies have remarked the high abrasion rate of gravel, further understanding of the evolution of nourishment material with time is needed. The peculiar behaviour of gravel material artificially added to an originally sandy beach suggests the need to modify the widely used classification of Jennings and Shulmeister (2002) adding a fourth additional beach typology, which could represent human-altered beaches.

Using Heliospheric Imaging for Storm Forecasting - SMEI CME Observations as a Tool for Operational Forecasting at AFWA

NASA Astrophysics Data System (ADS)

Webb, D. F.; Johnston, J. C.; Fry, C. D.; Kuchar, T. A.

2008-12-01

Observations of coronal mass ejections (CMEs) from heliospheric imagers such as the Solar Mass Ejection Imager (SMEI) can lead to significant improvements in operational space weather forecasting. We are working with the Air Force Weather Agency (AFWA) to ingest SMEI all-sky imagery with appropriate tools to help forecasters improve their operational space weather forecasts. We describe two approaches: 1) Near- real time analysis of propagating CMEs from SMEI images alone combined with near-Sun observations of CME onsets and, 2) Using these calculations of speed as a mid-course correction to the HAFv2 solar wind model forecasts. HAFv2 became operational at AFWA in late 2006. The objective is to determine a set of practical procedures that the duty forecaster can use to update or correct a solar wind forecast using heliospheric imager data. SMEI observations can be used inclusively to make storm forecasts, as recently discussed in Webb et al. (Space Weather, in press, 2008). We have developed a point-and-click analysis tool for use with SMEI images and are working with AFWA to ensure that timely SMEI images are available for analyses. When a frontside solar eruption occurs, especially if within about 45 deg. of Sun center, a forecaster checks for an associated CME observed by a coronagraph within an appropriate time window. If found, especially if the CME is a halo type, the forecaster checks SMEI observations about a day later, depending on the apparent initial CME speed, for possibly associated CMEs. If one is found, then the leading edge is measured over several successive frames and an elongation-time plot constructed. A minimum of three data points, i.e., over 3-4 orbits or about 6 hours, are necessary for such a plot. Using the solar source location and onset time of the CME from, e.g., SOHO observations, and assuming radial propagation, a distance-time relation is calculated and extrapolated to the 1 AU distance. As shown by Webb et al., the storm onset time is then expected to be about 3 hours after this 1 AU arrival time (AT). The prediction program is updated as more SMEI data become available. Currently when an appropriate solar event occurs, AFWA routinely runs the HAFv2 model to make a forecast of the shock and ejecta arrival times at Earth. SMEI data can be used to improve this prediction. The HAFv2 model can produce synthetic sky maps of predicted CME brightness for comparison with SMEI images. The forecaster uses SMEI imagery to observe and track the CME. The forecaster then measures the CME location and speed using the SMEI imagery and the HAFv2 synthetic sky maps. After comparing the SMEI and HAFv2 results, the forecaster can adjust a key input to HAFv2, such as the initial speed of the disturbance at the Sun or the mid-course speed. The forecaster then iteratively runs HAFv2 until the observed and forecast sky maps match. The final HAFv2 solution becomes the new forecast. When the CME/shock arrives at (or does not reach) Earth, the forecaster verifies the forecast and updates the forecast skill statistics. Eventually, we plan to develop a more automated version of this procedure.

High-Latitude Topside Ionospheric Vertical Electron-Density-Profile Changes in Response to Large Magnetic Storms

NASA Technical Reports Server (NTRS)

Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

2015-01-01

Large magnetic-storm induced changes have been detected in high-latitude topside vertical electron-density profiles Ne(h). The investigation was based on the large database of topside Ne(h) profiles and digital topside ionograms from the International Satellites for Ionospheric Studies (ISIS) program available from the NASA Space Physics Data Facility (SPDF) at http://spdf.gsfc.nasa.gov/isis/isis-status.html. This large database enabled Ne(h) profiles to be obtained when an ISIS satellite passed through nearly the same region of space before, during, and after a major magnetic storm. A major goal was to relate the magnetic-storm induced high-latitude Ne(h) profile changes to solar-wind parameters. Thus an additional data constraint was to consider only storms where solar-wind data were available from the NASA/SPDF OMNIWeb database. Ten large magnetic storms (with Dst less than -100 nT) were identified that satisfied both the Ne(h) profile and the solar-wind data constraints. During five of these storms topside ionospheric Ne(h) profiles were available in the high-latitude northern hemisphere and during the other five storms similar ionospheric data were available in the southern hemisphere. Large Ne(h) changes were observed during each one of these storms. Our concentration in this paper is on the northern hemisphere. The data coverage was best for the northern-hemisphere winter. Here Ne(h) profile enhancements were always observed when the magnetic local time (MLT) was between 00 and 03 and Ne(h) profile depletions were always observed between 08 and 10 MLT. The observed Ne(h) deviations were compared with solar-wind parameters, with appropriate time shifts, for four storms.

Geomagnetic storm effects on the occurrences of ionospheric irregularities over the African equatorial/low-latitude region

NASA Astrophysics Data System (ADS)

Amaechi, P. O.; Oyeyemi, E. O.; Akala, A. O.

2018-04-01

The study investigated the effects of intense geomagnetic storms of 2015 on the occurrences of large scale ionospheric irregularities over the African equatorial/low-latitude region. Four major/intense geomagnetic storms of 2015 were analyzed for this study. These storms occurred on 17th March 2015 (-229 nT), 22nd June 2015 (-204 nT), 7th October 2015 (-124 nT), and 20th December 2015 (-170 nT). Total Electron Content (TEC) data obtained from five African Global Navigation Satellite Systems (GNSS) stations, grouped into eastern and western sectors were used to derive the ionospheric irregularities proxy indices, e.g., rate of change of TEC (ROT), ROT index (ROTI) and ROTI daily average (ROTIAVE). These indices were characterized alongside with the disturbance storm time (Dst), the Y component of the Interplanetary Electric Field (IEFy), polar cap (PC) index and the H component of the Earth's magnetic field from ground-based magnetometers. Irregularities manifested in the form of fluctuations in TEC. Prompt penetration of electric field (PPEF) and disturbance dynamo electric field (DDEF) modulated the behaviour of irregularities during the main and recovery phases of the geomagnetic storms. The effect of electric field over both sectors depends on the local time of southward turning of IMF Bz. Consequently, westward electric field inhibited irregularities during the main phase of March and October 2015 geomagnetic storms, while for the June 2015 storm, eastward electric field triggered weak irregularities over the eastern sector. The effect of electric field on irregularities during December 2015 storm was insignificant. During the recovery phase of the storms, westward DDEF suppressed irregularities.

Precipitation Discrimination from Satellite Infrared Temperatures over the CCOPE Mesonet Region.

NASA Astrophysics Data System (ADS)

Weiss, Mitchell; Smith, Eric A.

1987-06-01

A quantitative investigation of the relationship between satellite-derived cloud-top temperature parameters and the detection of intense convective rainfall is described. The area of study is that of the Cooperative Convective Precipitation Experiment (CCOPE), which was held near Miles City, Montana during the summer of 1981. Cloud-top temperatures, derived from the GOES-West operational satellite, were used to calculate a variety of parameters for objectively quantifying the convective intensity of a storm. A dense network of rainfall provided verification of surface rainfall. The cloud-top temperature field and surface rainfall data were processed into equally sized grid domains in order to best depict the individual samples of instantaneous precipitation.The technique of statistical discriminant analysis was used to determine which combinations of cloud-top temperature parameters best classify rain versus no-rain occurrence using three different rain-rate cutoffs: 1, 4, and 10 mm h1. Time lags within the 30 min rainfall verification were tested to determine the optimum time delay associated with rainfall reaching the ground.A total of six storm cases were used to develop and test the statistical models. Discrimination of rain events was found to be most accurate when using a 10 mm h1 rain-rate cutoff. Use parameters designated as coldest cloud-top temperature, the spatial mean of coldest cloud-top temperature, and change over time of mean coldest cloud-top temperature were found to be the best classifiers of rainfall in this study. Combining both a 10-min time lag (in terms of surface verification) with a 10 mm h1 rain-rate threshold resulted in classifying over 60% of all rain and no-rain cases correctly.

Monitoring inland storm tide and flooding from Hurricane Irene along the Atlantic Coast of the United States, August 2011

USGS Publications Warehouse

McCallum, Brian E.; Painter, Jaime A.; Frantz, Eric R.

2012-01-01

The U.S. Geological Survey (USGS) deployed a temporary monitoring network of water-level sensors at 212 locations along the Atlantic coast from South Carolina to Maine during August 2011 to record the timing, areal extent, and magnitude of inland hurricane storm tide and coastal flooding generated by Hurricane Irene. Water-level sensor locations were selected to augment existing tide-gage networks to ensure adequate monitoring in areas forecasted to have substantial storm tide. As defined by the National Oceanic and Atmospheric Administration (NOAA; 2011a,b), storm tide is the water-level rise generated by a coastal storm as a result of the combination of storm surge and astronomical tide.

Lightning activity observed in upper and lower portions of storms and its relationship to storm structure from VHF mapping and Doppler radar

NASA Technical Reports Server (NTRS)

Taylor, W. L.; Rust, W. D.; Macgorman, D. R.; Brandes, E. A.

1983-01-01

Space time mapping of very high frequencies (VHF) sources reveals lightning processes for cloud to ground (CG) and for large intracloud (IC) flashes are confined to an altitude below about 10 km and closely associated with the central high reflectivity region of a storm. Another class of IC flashes was identified that produces a splattering of small sources within the main electrically active volume of a storm and also within a large divergent wind canopy at the top of a storm. There is no apparent temporal association between the small high altitude IC flashes occurring almost continuously and the large IC and CG flashes sporadically occurring in the lower portions of storms.

Global Observations of Magnetospheric High-m Poloidal Waves During the 22 June 2015 Magnetic Storm

NASA Technical Reports Server (NTRS)

Le, G.; Chi, P. J.; Strangeway, R. J.; Russell, C. T.; Slavin, J. A.; Takahashi, K.; Singer, H. J.; Anderson, B. J.; Bromund, K.; Fischer, D.;

Global observations of magnetospheric high-m poloidal waves during the 22 June 2015 magnetic storm.

PubMed

Le, G; Chi, P J; Strangeway, R J; Russell, C T; Slavin, J A; Takahashi, K; Singer, H J; Anderson, B J; Bromund, K; Fischer, D; Kepko, E L; Magnes, W; Nakamura, R; Plaschke, F; Torbert, R B

2017-04-28

We report global observations of high- m poloidal waves during the recovery phase of the 22 June 2015 magnetic storm from a constellation of widely spaced satellites of five missions including Magnetospheric Multiscale (MMS), Van Allen Probes, Time History of Events and Macroscale Interactions during Substorm (THEMIS), Cluster, and Geostationary Operational Environmental Satellites (GOES). The combined observations demonstrate the global spatial extent of storm time poloidal waves. MMS observations confirm high azimuthal wave numbers ( m  ~ 100). Mode identification indicates the waves are associated with the second harmonic of field line resonances. The wave frequencies exhibit a decreasing trend as L increases, distinguishing them from the single-frequency global poloidal modes normally observed during quiet times. Detailed examination of the instantaneous frequency reveals discrete spatial structures with step-like frequency changes along L . Each discrete L shell has a steady wave frequency and spans about 1  R E , suggesting that there exist a discrete number of drift-bounce resonance regions across L shells during storm times.

Characteristics of recent dust storms over the Indian region using real time multi-satellite observations from the direct broadcast receiving system at IMD

NASA Astrophysics Data System (ADS)

Mitra, A. K.; Sharma, A. K.; Soni, V. K.; Kundu, P. K.

2013-04-01

In this study, observations from microwave satellites, visible and infrared instruments have been analyzed to detect dust storm over north and north-west part of India during 18-23 March 2012. This study investigated the approach to utilize the multi satellite data of Moderate Resolution Imaging Spectroradiometer (MODIS) on-board the Terra and Aqua satellite and the Advanced Microwave Sounding Unit (AMSU) on-board NOAA satellite to study the characteristics of dust storms from real time direct broadcast (DB) receiving system installed at three places of India Meteorological Department (IMD). The dust storm detection is based on the infrared brightness temperature (BT) difference between channels at 11 and 12 μm and polarized BT difference between two channels of 89 and 23.8 GHz. It is found that the significant differences between the BT of channel 89 and 23.8 can be used as a discriminator of identifying dust storm. The Total Ozone Mapping Spectroradiometer (TOMS) Aerosol Index (AI) and AMSU-A 23 GHz channel BT from NOAA satellite over the north and north-west part of India have also been analyzed. The result indicated the characteristic behavior between BT and AI during the different phases of the dust storm. Finally, the occurrence of dust outbreaks has also been validated with sky radiometer of IMD, which confirms the presence of a dust storm over the Indian region. Further, the findings of the study and its approaches apply to the other dust storm cases which occurred during the months of April and June 2012. The integrated approach suggested the potential to use high resolution data of microwave as well as thermal-infrared using multi-satellite observations from real time direct broadcast system for the detection of severe, moderate or weak dust storms very well. The approach is found to be promising for operational application.

The Unknown Hydrogen Exosphere: Space Weather Implications

NASA Astrophysics Data System (ADS)

Krall, J.; Glocer, A.; Fok, M.-C.; Nossal, S. M.; Huba, J. D.

2018-03-01

Recent studies suggest that the hydrogen (H) density in the exosphere and geocorona might differ from previously assumed values by factors as large as 2. We use the SAMI3 (Sami3 is Also a Model of the Ionosphere) and Comprehensive Inner Magnetosphere-Ionosphere models to evaluate scenarios where the hydrogen density is reduced or enhanced, by a factor of 2, relative to values given by commonly used empirical models. We show that the rate of plasmasphere refilling following a geomagnetic storm varies nearly linearly with the hydrogen density. We also show that the ring current associated with a geomagnetic storm decays more rapidly when H is increased. With respect to these two space weather effects, increased exosphere hydrogen density is associated with reduced threats to space assets during and following a geomagnetic storm.

Economic costs of extratropical storms under climate change: An application of FUND

NASA Astrophysics Data System (ADS)

Narita, D.; Tol, R.; Anthoff, D.

2009-12-01

Extratropical cyclones have attracted some attention in climate policy circles as a possible significant damage factor of climate change. This study conducts an assessment of economic impacts of increased storm activities under climate change with the integrated assessment model FUND 3.5. FUND is a model that calculates damages of climate change for 16 regions by making use of exogenous scenarios of socioeconomic variables (for details of our estimation approach, see our working paper whose URL is indicated below). Our estimation shows that in the base case, the direct economic damage of enhanced storms due to climate change amounts to $2.8 billion globally (approximately 38% of the total economic loss of storms at present) at the year 2100, while the ratio to the world GDP is 0.0009%. The regional results (Figure 1) indicate that the economic effect of extratropical storms with climate change would have relatively minor importance for the US (USA): The enhanced extratropical storm damage (less than 0.001% of GDP for the base case) is one order of magnitude lower than the tropical cyclone damage (roughly 0.01% GDP) calculated by the same version of FUND. In the regions without strong tropical cyclone influence, such as Western Europe (WEU) and Australia and New Zealand (ANZ), the extratropical storms might have some more significance as a possible damage factor of climate change. Especially for the latter, the direct economic damage could amount to more than 0.006% of GDP. Still, the impact is small relative to the income growth expected in these regions. Figure 1. Increased direct economic loss at the year 2100 for selected regions (results are shown for the three different baselines: the years 1986-2005, 1976-2005, and 1996-2005). US - USA; Canada - CAN; Western Europe - WEU; Australia and New Zealand - ANZ.

Variations of Morphologic Changes induced by Tropical Storm Debby along Three Barrier Island, West-Central Florida, USA

NASA Astrophysics Data System (ADS)

Wang, P.; Roberts, T.

2012-12-01

Tropical Storm Debby generated sustained high waves and elevated water levels for nearly three days from June 24th to 26th, 2012, inducing substantial changes in beach and nearshore morphology. In addition, the storm winds and high waves approached the coast from a highly oblique angle from the south, driving substantial northward longshore sand transport, opposite to the regional net annual southward transport. A total of 145 beach and nearshore profiles along 3 adjacent barrier islands were surveyed 2 weeks before and one week after the storm impact. Overall, dune, beach, intertidal, and immediate subtidal areas suffered erosion, while deposition was measured over the nearshore bar. Beach recovery in the form of ridge and runnel development occurred as the storm energy subsided. Substantial longshore variations of storm-induced beach changes were measured, including both severe dune/beach/berm erosion and storm berm accretion, and both onshore and offshore migration of nearshore bar. Factors controlling these longshore variations include: 1) the oblique approaching of the storm forcing, 2) pre-storm beach morphology and chronic erosional or accretional trends, 3) sediment supply, and 4) tidal inlet and beach interactions. Wide spreading dune scarping occurred along the 30-km studied coast. Based on the pre- and post-storm survey data, a balanced sediment budget is obtained accounting for sand volume loss from dune, beach, intertidal, and subtidal zones, and sand gains over the nearshore bar and along the northern sections of the beach.

Population vulnerability to storm surge flooding in coastal Virginia, USA.

PubMed

Liu, Hua; Behr, Joshua G; Diaz, Rafael

2016-07-01

This study aims to assess the vulnerability of populations to storm surge flooding in 12 coastal localities of Virginia, USA. Population vulnerability is assessed by way of 3 physical factors (elevation, slope, and storm surge category), 3 built-up components (road availability, access to hospitals, and access to shelters), and 3 household conditions (storm preparedness, financial constraints to recovering from severe weather events, and health fragility). Fuzzy analysis is used to generate maps illustrating variation in several types of population vulnerability across the region. When considering physical factors and household conditions, the most vulnerable neighborhoods to sea level rise and storm surge flooding are largely found in urban areas. However, when considering access to critical infrastructure, we find rural residents to be more vulnerable than nonrural residents. These detailed assessments can inform both local and state governments in catastrophic planning. In addition, the methodology may be generalized to assess vulnerability in other coastal corridors and communities. The originality is highlighted by evaluating socioeconomic conditions at refined scale, incorporating a broader range of human perceptions and predispositions, and employing a geoinformatics approach combining physical, built-up, and socioeconomic conditions for population vulnerability assessment. Integr Environ Assess Manag 2016;12:500-509. © 2015 SETAC. © 2015 SETAC.

Barrier Island Morphology and Sediment Characteristics Affect the Recovery of Dune Building Grasses following Storm-Induced Overwash

PubMed Central

Brantley, Steven T.; Bissett, Spencer N.; Young, Donald R.; Wolner, Catherine W. V.; Moore, Laura J.

2014-01-01

Barrier islands are complex and dynamic systems that provide critical ecosystem services to coastal populations. Stability of these systems is threatened by rising sea level and the potential for coastal storms to increase in frequency and intensity. Recovery of dune-building grasses following storms is an important process that promotes topographic heterogeneity and long-term stability of barrier islands, yet factors that drive dune recovery are poorly understood. We examined vegetation recovery in overwash zones on two geomorphically distinct (undisturbed vs. frequently overwashed) barrier islands on the Virginia coast, USA. We hypothesized that vegetation recovery in overwash zones would be driven primarily by environmental characteristics, especially elevation and beach width. We sampled species composition and environmental characteristics along a continuum of disturbance from active overwash zones to relict overwash zones and in adjacent undisturbed environments. We compared species assemblages along the disturbance chronosequence and between islands and we analyzed species composition data and environmental measurements with Canonical Correspondence Analysis to link community composition with environmental characteristics. Recovering and geomorphically stable dunes were dominated by Ammophila breviligulata Fernaud (Poaceae) on both islands while active overwash zones were dominated by Spartina patens (Aiton) Muhl. (Poaceae) on the frequently disturbed island and bare sand on the less disturbed island. Species composition was associated with environmental characteristics only on the frequently disturbed island (p = 0.005) where A. breviligulata was associated with higher elevation and greater beach width. Spartina patens, the second most abundant species, was associated with larger sediment grain size and greater sediment size distribution. On the less frequently disturbed island, time since disturbance was the only factor that affected community composition. Thus, factors driving the abundance of dune-building grasses and subsequent recovery of dunes varied between the two geomorphically distinct islands. PMID:25148028

Military Hydrology. Report 8. Feasibility of Utilizing Satellite and Radar Data in Hydrologic Forecasting.

DTIC Science & Technology

1985-09-01

Extratropical Storm ," Draft Report. Atlas, David. 1964. "Advances in Radar Meteorology," Advances in Geophysics, Vol 10, Academic Press, N.Y., pp 318-478. Barnes...forecasting purposes, data on storm morphology, direction of movement, and rate of movement are re- quired in addition to the data cited above. 7...or storm duration. He also showed that, for a given sampling error, the gage density needed for warm season storms was two to three times greater than

Centralized Storm Information System (CSIS)

NASA Technical Reports Server (NTRS)

Norton, C. C.

1985-01-01

A final progress report is presented on the Centralized Storm Information System (CSIS). The primary purpose of the CSIS is to demonstrate and evaluate real time interactive computerized data collection, interpretation and display techniques as applied to severe weather forecasting. CSIS objectives pertaining to improved severe storm forecasting and warning systems are outlined. The positive impact that CSIS has had on the National Severe Storms Forecast Center (NSSFC) is discussed. The benefits of interactive processing systems on the forecasting ability of the NSSFC are described.

Space Weather Monitoring for ISS Geomagnetic Storm Studies

NASA Technical Reports Server (NTRS)

Minow, Joseph I.; Parker, Neergaard

2013-01-01

The International Space Station (ISS) space environments community utilizes near real time space weather data to support a variety of ISS engineering and science activities. The team has operated the Floating Potential Measurement Unit (FPMU) suite of plasma instruments (two Langmuir probes, a floating potential probe, and a plasma impedance probe) on ISS since 2006 to obtain in-situ measurements of plasma density and temperature along the ISS orbit and variations in ISS frame potential due to electrostatic current collection from the plasma environment (spacecraft charging) and inductive (vxB) effects from the vehicle motion across the Earth s magnetic field. An ongoing effort is to use FPMU for measuring the ionospheric response to geomagnetic storms at ISS altitudes and investigate auroral charging of the vehicle as it passes through regions of precipitating auroral electrons. This work is challenged by restrictions on FPMU operations that limit observation time to less than about a third of a year. As a result, FPMU campaigns ranging in length from a few days to a few weeks are typically scheduled weeks in advance for ISS engineering and payload science activities. In order to capture geomagnetic storm data under these terms, we monitor near real time space weather data from NASA, NOAA, and ESA sources to determine solar wind disturbance arrival times at Earth likely to be geoeffective (including coronal mass ejections and high speed streams associated with coronal holes) and activate the FPMU ahead of the storm onset. Using this technique we have successfully captured FPMU data during a number of geomagnetic storm periods including periods with ISS auroral charging. This presentation will describe the strategies and challenges in capturing FPMU data during geomagnetic storms, the near real time space weather resources utilized for monitoring the space weather environment, and provide examples of auroral charging data obtained during storm operations.

Temporal evolution of ion spectral structures during a geomagnetic storm: Observations and modeling

NASA Astrophysics Data System (ADS)

Ferradas, C.; Zhang, J.; Spence, H. E.; Kistler, L. M.; Larsen, B.; Reeves, G. D.; Skoug, R. M.; Funsten, H. O.

2016-12-01

During the last decades several missions have recorded the presence of dynamic spectral features of energetic ions in the inner magnetosphere. We present a case study of the temporal evolution of H+, He+, and O+ spectral structures throughout the geomagnetic storm of 2 October 2013. We use data from the Helium, Oxygen, Proton, and Electron (HOPE) mass spectrometer onboard Van Allen Probe A to analyze the spectral structures in the energy range of 1- 50 keV. We find that the characteristics of the ion structures follow a cyclic pattern, the observed features changing dramatically as the storm starts and then returning to its initial pre-storm state. Quiet, pre-storm times are characterized by multiple and often complex flux structures at narrow energy bands. During the storm main phase, the observed features become simple, with no nose structures or only one nose structure present in the energy-time spectrograms. As the inner magnetosphere recovers from the storm, more complex structures appear once again. Additionally, the heavy ion spectral features are generally more complex than the H+ features, with multiple noses being observed more often in the heavy ion spectra. We use a model of ion drift and losses due to charge exchange to understand the formation of the spectral features and their species dependence.

Magnetic Storms

NASA Technical Reports Server (NTRS)

Tsurutani, Bruce T.; Gonzalez, Walter D.

1998-01-01

One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine. A few years later, speculation on a causal relationship between flares and storms arose when Carrington reported that a large magnetic storm followed the great September 1859 solar flare. However, it was not until this century that a well-accepted statistical survey on large solar flares and geomagnetic storms was performed, and a significant correlation between flares and geomagnetic storms was noted. Although the two phenomena, one on the Sun and the other on the Earth, were statistically correlated, the exact physical linkage was still an unknown at this time. Various hypotheses were proposed, but it was not until interplanetary spacecraft measurements were available that a high-speed plasma stream rich in helium was associated with an intense solar flare. The velocity of the solar wind increased just prior to and during the helium passage, identifying the solar ejecta for the first time. Space plasma measurements and Skylab's coronagraph images of coronal mass elections (CMES) from the Sun firmly established the plasma link between the Sun and the Earth. One phenomenon associated with magnetic storms is brilliant "blood" red auroras, as shown.

Torsional Alfvén Wave Embedded ICME Magnetic Cloud and Corresponding Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Raghav, Anil N.; Kule, Ankita; Bhaskar, Ankush; Mishra, Wageesh; Vichare, Geeta; Surve, Shobha

2018-06-01

Energy transfer during the interaction of large-scale solar wind structure and the Earth’s magnetosphere is a chronic issue in space-weather studies. To understand this, researchers widely studied the geomagnetic storm and substorm phenomena. The present understanding suggests that the long duration of the southward interplanetary magnetic field component is the most important parameter for the geomagnetic storm. Such a long duration strong southward magnetic field is often associated with ICMEs, torsional Alfvén fluctuations superposed corotating interacting regions (CIRs), and fast solar wind streams. Torsional Alfvén fluctuations embedded CIRs have been known of for a long time; however, magnetic clouds embedded with such fluctuations are rarely observed. The presence of Alfvén waves in the ICME/MC and the influence of these waves on the storm evolution remains an interesting topic of study. The present work confirms the torsional Alfvén waves in a magnetic cloud associated with a CME launched on 2011 February 15, which impacted the Earth’s magnetosphere on 2011 February 18. Furthermore, observations indicate that these waves inject energy into the magnetosphere during the storm and contribute to the long recovery time of geomagnetic storms. Our study suggests that the presence of torsional Alfvén waves significantly controls the storm dynamics.

Effects of Geomagnetic Storms on the Postsunset Vertical Plasma Drift in the Equatorial Ionosphere

NASA Astrophysics Data System (ADS)

Huang, Chao-Song

2018-05-01

It has been observed that geomagnetic storms cause suppression of the occurrence of equatorial spread F or plasma bubbles in the evening sector. In this study, we use ion drift data measured by the Communication/Navigation Outage Forecasting System satellite over 6 years (2008-2014) to derive the dependence of the vertical ion drift at the prereversal enhancement peak on the strength of magnetic storms (the Dst index). It is found that the average vertical ion drift does not change much for Dst in the range between 0 and -60 nT but decreases approximately linearly with the increasing magnitude of Dst for Dst < -60 nT. The net decrease in the average vertical ion drift is 30 m/s when Dst changes from -60 to -90 nT. This result is derived when the ion drift data during the storm main phase are excluded, so the decrease of the vertical ion drift is caused by storm time disturbance dynamo. A possible interpretation of this phenomenon is that geomagnetic activity must be strong enough (e.g., Dst < -60 nT) so disturbance winds can reach the equatorial region and change plasma drifts there. The storm time disturbance dynamo becomes dominant in the equatorial ionospheric dynamics near the end of the storm main phase, 4.7 hr after the storm onset. The postsunset vertical ion drift is significantly decreased during the early stage of the storm recovery phase but becomes almost fully recovered when Dst increases close to -60 nT.

Pollutant loading from low-density residential neighborhoods in California.

PubMed

Bale, Andrew E; Greco, Steven E; Pitton, Bruno J L; Haver, Darren L; Oki, Lorence R

2017-08-01

This paper presents a comparison of pollutant load estimations for runoff from two geographically distinct residential suburban neighborhoods in northern and southern California. The two neighborhoods represent a single urban land use type: low-density residential in small catchments (<0.3 km 2 ) under differing regional climates and irrigation practices. Pollutant loads of pesticides, nutrients, and drinking water constituents of concern are estimated for both storm and non-storm runoff. From continuous flow monitoring, it was found that a daily cycle of persistent runoff that peaks mid-morning occurs at both sites. These load estimations indicate that many residential neighborhoods in California produce significant non-storm pollutant loads year-round. Results suggest that non-storm flow accounted for 47-69% of total annual runoff and significantly contributed to annual loading rates of most nutrients and pesticides at both sites. At the Southern California site, annual non-storm loads are 1.2-10 times higher than storm loads of all conventional constituents and nutrients with one exception (total suspended solids). At the Northern California site, annual storm loads range from 51 to 76% of total loads for all conventional constituents and nutrients with one exception (total dissolved solids). Non-storm yields of pesticides at the Southern California site range from 1.3-65 times higher than those at the Northern California site. The disparity in estimated pollutant loads between the two sites indicates large potential variation from site-to-site within the state and suggests neighborhoods in drier and milder climates may produce significantly larger non-storm loads due to persistent dry season runoff and year-round pest control.

An entropy decision approach in flash flood warning: rainfall thresholds definition

NASA Astrophysics Data System (ADS)

Montesarchio, V.; Napolitano, F.; Ridolfi, E.

2009-09-01

Flash floods events are floods characterised by very rapid response of the basins to the storms, and often they involve loss of life and damage to common and private properties. Due to the specific space-time scale of this kind of flood, generally only a short lead time is available for triggering civil protection measures. Thresholds values specify the precipitation amount for a given duration that generates a critical discharge in a given cross section. The overcoming of these values could produce a critical situation in river sites exposed to alluvial risk, so it is possible to compare directly the observed or forecasted precipitation with critical reference values, without running on line real time forecasting systems. This study is focused on the Mignone River basin, located in Central Italy. The critical rainfall threshold values are evaluated minimising an utility function based on the informative entropy concept. The study concludes with a system performance analysis, in terms of correctly issued warning, false alarms and missed alarms.

The International Reference Ionosphere - Status 2013

NASA Astrophysics Data System (ADS)

Bilitza, Dieter

2015-04-01

This paper describes the latest version of the International Reference Ionosphere (IRI) model. IRI-2012 includes new models for the electron density and ion densities in the region below the F-peak, a storm-time model for the auroral E-region, an improved electron temperature model that includes variations with solar activity, and for the first time a description of auroral boundaries. In addition, the thermosphere model required for baseline neutral densities and temperatures was upgraded from MSIS-86 to the newer NRLMSIS-00 model and Corrected Geomagnetic coordinates (CGM) were included in IRI as an additional coordinate system for a better representation of auroral and polar latitudes. Ongoing IRI activities towards the inclusion of an improved model for the F2 peak height hmF2 are discussed as are efforts to develop a "Real-Time IRI". The paper is based on an IRI status report presented at the 2013 IRI Workshop in Olsztyn, Poland. The IRI homepage is at

The FASTER Approach: A New Tool for Calculating Real-Time Tsunami Flood Hazards

NASA Astrophysics Data System (ADS)

Wilson, R. I.; Cross, A.; Johnson, L.; Miller, K.; Nicolini, T.; Whitmore, P.

2014-12-01

In the aftermath of the 2010 Chile and 2011 Japan tsunamis that struck the California coastline, emergency managers requested that the state tsunami program provide more detailed information about the flood potential of distant-source tsunamis well ahead of their arrival time. The main issue is that existing tsunami evacuation plans call for evacuation of the predetermined "worst-case" tsunami evacuation zone (typically at a 30- to 50-foot elevation) during any "Warning" level event; the alternative is to not call an evacuation at all. A solution to provide more detailed information for secondary evacuation zones has been the development of tsunami evacuation "playbooks" to plan for tsunami scenarios of various sizes and source locations. To determine a recommended level of evacuation during a distant-source tsunami, an analytical tool has been developed called the "FASTER" approach, an acronym for factors that influence the tsunami flood hazard for a community: Forecast Amplitude, Storm, Tides, Error in forecast, and the Run-up potential. Within the first couple hours after a tsunami is generated, the National Tsunami Warning Center provides tsunami forecast amplitudes and arrival times for approximately 60 coastal locations in California. At the same time, the regional NOAA Weather Forecast Offices in the state calculate the forecasted coastal storm and tidal conditions that will influence tsunami flooding. Providing added conservatism in calculating tsunami flood potential, we include an error factor of 30% for the forecast amplitude, which is based on observed forecast errors during recent events, and a site specific run-up factor which is calculated from the existing state tsunami modeling database. The factors are added together into a cumulative FASTER flood potential value for the first five hours of tsunami activity and used to select the appropriate tsunami phase evacuation "playbook" which is provided to each coastal community shortly after the forecast is provided.

Validation of TRMM Precipitation Radar Through Comparison of its Multi-Year Measurements to Ground-Based Radar

NASA Technical Reports Server (NTRS)

Liao, Liang; Meneghini, Robert

2010-01-01

A procedure to accurately resample spaceborne and ground-based radar data is described, and then applied to the measurements taken from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and the ground-based Weather Surveillance Radar-1988 Doppler (WSR-88D or WSR) for the validation of the PR measurements and estimates. Through comparisons with the well-calibrated, non-attenuated WSR at Melbourne, Florida for the period 1998-2007, the calibration of the Precipitation Radar (PR) aboard the TRMM satellite is checked using measurements near the storm top. Analysis of the results indicates that the PR, after taking into account differences in radar reflectivity factors between the PR and WSR, has a small positive bias of 0.8 dB relative to the WSR, implying a soundness of the PR calibration in view of the uncertainties involved in the comparisons. Comparisons between the PR and WSR reflectivities are also made near the surface for evaluation of the attenuation-correction procedures used in the PR algorithms. It is found that the PR attenuation is accurately corrected in stratiform rain but is underestimated in convective rain, particularly in heavy rain. Tests of the PR estimates of rainfall rate are conducted through comparisons in the overlap area between the TRMM overpass and WSR scan. Analyses of the data are made both on a conditional basis, in which the instantaneous rain rates are compared only at those pixels where both the PR and WSR detect rain, and an unconditional basis, in which the area-averaged rain rates are estimated independently for the PR and WSR. Results of the conditional rain comparisons show that the PR-derived rain is about 9% greater and 19% less than the WSR estimates for stratiform and convective storms, respectively. Overall, the PR tends to underestimate the conditional mean rain rate by 8% for all rain categories, a finding that conforms to the results of the area-averaged rain (unconditional) comparisons.

Electrical storms and their prognostic implications.

PubMed

Awan, Zahid Aslam; ul Hassan, Mahmood; Bangash, Kamran; Shah, Bakhtawar; Noor, Lubna

2009-01-01

Prevention of sudden cardiac death has always been a challenge for electrophysiologists and to date, automatic implantable cardiovertor defibrillator (AICD) is found to be the only remedy. This device delivers an intracardiac shock whenever it senses a fatal ventricular arrhythmia in order to achieve sinus rhythm. If the delivery of these intracardiac shocks becomes frequent, the situation is declared as an electrical storm. This article deals with the frequency, precipitating factors and prevention of electrical storms. One hundred and ten episodes of electrical storms (a total of 668 shocks) were retrospectively analysed in 25 recipients of automatic implantable cardioverter defibrillators. ECG, echocardiography, serum electrolytes, urea and creatinine were done for all the patients, and they were hospitalized for a minimum of 24 hours. During the 3 year study period, all the 25 patients with an implantable cardiovertor defibrillator, on an average, received one shock per two years. However, 12 out of these 25 patients (50%) had more than two shocks within 24 hours. Most of these patients with electrical storms were having active ischemia, electrolytes imbalances or renal failure. Electrical storms are common in patients with coronary artery disease with impaired left ventricular functions. Ischemia, electrolytes imbalances and renal failure predispose to the electrical storms. Electrical Storms are predictors of poor prognosis.

When time affects space: Dispersal ability and extreme weather events determine metacommunity organization in marine sediments.

PubMed

Corte, Guilherme N; Gonçalves-Souza, Thiago; Checon, Helio H; Siegle, Eduardo; Coleman, Ross A; Amaral, A Cecília Z

2018-05-01

Community ecology has traditionally assumed that the distribution of species is mainly influenced by environmental processes. There is, however, growing evidence that environmental (habitat characteristics and biotic interactions) and spatial processes (factors that affect a local assemblage regardless of environmental conditions - typically related to dispersal and movement of species) interactively shape biological assemblages. A metacommunity, which is a set of local assemblages connected by dispersal of individuals, is spatial in nature and can be used as a straightforward approach for investigating the interactive and independent effects of both environmental and spatial processes. Here, we examined (i) how environmental and spatial processes affect the metacommunity organization of marine macroinvertebrates inhabiting the intertidal sediments of a biodiverse coastal ecosystem; (ii) whether the influence of these processes is constant through time or is affected by extreme weather events (storms); and (iii) whether the relative importance of these processes depends on the dispersal abilities of organisms. We found that macrobenthic assemblages are influenced by each of environmental and spatial variables; however, spatial processes exerted a stronger role. We also found that this influence changes through time and is modified by storms. Moreover, we observed that the influence of environmental and spatial processes varies according to the dispersal capabilities of organisms. More effective dispersers (i.e., species with planktonic larvae) are more affected by spatial processes whereas environmental variables had a stronger effect on weaker dispersers (i.e. species with low motility in larval and adult stages). These findings highlight that accounting for spatial processes and differences in species life histories is essential to improve our understanding of species distribution and coexistence patterns in intertidal soft-sediments. Furthermore, it shows that storms modify the structure of coastal assemblages. Given that the influence of spatial and environmental processes is not consistent through time, it is of utmost importance that future studies replicate sampling over different periods so the influence of temporal and stochastic factors on macrobenthic metacommunities can be better understood. Copyright © 2018 Elsevier Ltd. All rights reserved.

Coupling of the Matched Gravity and Electromagnetic Fields of the Sun with Jupiter and its Moons Together in Nearest Portion of Jupiter's Orbit to the Sun as the Main Cause of the Peak of Approximately 11 Yearly Solar Cycles and Hazards from Solar Storms

NASA Astrophysics Data System (ADS)

Gholibeigian, Kazem; Gholibeigian, Hassan

2016-04-01

On March 13, 1989 the entire province of Quebec Blackout by solar storm during solar cycle 22. The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm during solar cycle 10. The solar storm of 2012 during solar cycle 24 was of similar magnitude, but it passed Earth's orbit without striking the plane. All of these solar storms occurred in the peak of 11 yearly solar cycles. In this way, the White House in its project which is focusing on hazards from solar system, in a new strategy and action plan to increase protection from damaging solar emissions, should focus on coupling of the matched Gravity and Electromagnetic Fields)GEFs) of the Sun with Jupiter and its moons together. On the other hand, in solar system, the Jupiter's gravity has largest effect to the Sun's core and its dislocation, because the gravity force between the Jupiter and the Sun is 11.834 times, In addition overlapping of the solar cycles with the Jupiter's orbit period is 11.856 years. These observable factors lead us to the effect of the Jupiter and Sun gravity fields coupling as the main cause of the approximately 11 years duration for solar cycles. Its peak in each cycle is when the Jupiter is in nearest portion to the Sun in its orbit. In this way, the other planets in their coupling with Sun help to the variations and strengthening solar cycles. [Gholibeigian, 7/24/2015http://adsabs.harvard.edu/abs/2014EGU]. In other words, the both matched GEFs are generating by the large scale forced convection system inside the stars and planets [Gholibeigian et. al, AGU Fall Meeting 2015]. These two fields are couple and strengthening each other. The Jupiter with its 67 moons generate the largest coupled and matched GEFs in its core and consequently strongest effect on the Sun's core. Generation and coupling of the Jupiter's GEFs with its moons like Europa, Io and Ganymede make this planet of thousands of times brighter and many times bigger than Earth as the strongest variable GEFs in solar system after the Sun. For example, Ganymede is the largest moon of Jupiter and in the Solar System. Completing an orbit in roughly seven days. It means that it generates 52 GEFs oscillations (loading, unloading) per year in solar cycle while it is rotating around the Jupiter. New observations of the planet's extreme ultraviolet emissions show that bright explosions of Jupiter's aurora by the planet-moon interaction, not by solar activity [Tomoki Kimura, JAEA]. Coupling of Jupiter's GEFs and its moons with the Sun generate very strong GEFs and approximately 11 yearly solar cycles. The peaks of each cycle is when the Jupiter passes from the nearest portion of its orbit to the Sun. which some of its peaks generate gigantic solar storms and hazards to the Earth. The Earth passes from between of Sun and Jupiter eleven times in each solar cycle and may be under shooting of storms from the both side specially during 2-3 years in cycle's peak.

Reversing storm hotspots on sandy beaches: Spatial and temporal characteristics

USGS Publications Warehouse

List, J.H.; Farris, A.S.; Sullivan, C.

2006-01-01

Coastal erosion hotspots are defined as sections of coast that exhibit significantly higher rates of erosion than adjacent areas. This paper describes the spatial and temporal characteristics of a recently identified type of coastal erosion hotspot, which forms in response to storms on uninterrupted sandy coasts largely free from human intervention. These are referred to here as reversing storm hotspots because the erosion is reversed by accretion of a similar magnitude to the storm-induced erosion. The accretion occurs within a few days or weeks of fair weather after the storm. Reversing storm hotspots observed here, on two US east coast beaches, have a longshore length averaging 3.86 km, a cross-shore excursion (magnitude of erosion or accretion) averaging 15.4 m, and a time scale of days to weeks associated with individual storm events. These spatial and temporal scales clearly distinguish reversing storm hotspots from previously described forms of longshore variability in erosion, including those attributed to several types of shoreline undulations and hotspots associated with long-term shoreline change. 

Mars atmospheric water vapor abundance: 1996-1997

NASA Astrophysics Data System (ADS)

Sprague, A. L.; Hunten, D. M.; Doose, L. R.; Hill, R. E.

2003-05-01

Measurements of martian atmospheric water vapor made throughout Ls = 18.0°-146.4° (October 3, 1996-July 12, 1997) show changes in Mars humidity on hourly, daily, and seasonal time scales. Because our observing program during the 1996-1997 Mars apparition did not include concomitant measurement of nearby CO 2 bands, high northern latitude data were corrected for dust and aerosol extinction assuming an optical depth of 0.8, consistent with ground-based and HST imaging of northern dust storms. All other measurements with airmass greater than 3.5 were corrected using a total optical depth of 0.5. Three dominant results from this data set are as follows: (1) pre- and post-opposition measurements made with the slit crossing many hours of local time on Mars' Earth-facing disk show a distinct diurnal pattern with highest abundances around and slightly after noon with low abundances in the late afternoon, (2) measurements of water vapor over the Mars Pathfinder landing site (Carl Sagan Memorial Station) on July 12, 1997, found 21 ppt μm in the spatial sector centered near 19° latitude, 36° longitude while abundances around the site varied from as low as 6 to as high as 28 ppt μm, and (3) water vapor abundance is patchy on hourly and daily time scales but follows the usual seasonal trends.

A neural network model of three-dimensional dynamic electron density in the inner magnetosphere

NASA Astrophysics Data System (ADS)

Chu, X.; Bortnik, J.; Li, W.; Ma, Q.; Denton, R.; Yue, C.; Angelopoulos, V.; Thorne, R. M.; Darrouzet, F.; Ozhogin, P.; Kletzing, C. A.; Wang, Y.; Menietti, J.

2017-09-01

A plasma density model of the inner magnetosphere is important for a variety of applications including the study of wave-particle interactions, and wave excitation and propagation. Previous empirical models have been developed under many limiting assumptions and do not resolve short-term variations, which are especially important during storms. We present a three-dimensional dynamic electron density (DEN3D) model developed using a feedforward neural network with electron densities obtained from four satellite missions. The DEN3D model takes spacecraft location and time series of solar and geomagnetic indices (F10.7, SYM-H, and AL) as inputs. It can reproduce the observed density with a correlation coefficient of 0.95 and predict test data set with error less than a factor of 2. Its predictive ability on out-of-sample data is tested on field-aligned density profiles from the IMAGE satellite. DEN3D's predictive ability provides unprecedented opportunities to gain insight into the 3-D behavior of the inner magnetospheric plasma density at any time and location. As an example, we apply DEN3D to a storm that occurred on 1 June 2013. It successfully reproduces various well-known dynamic features in three dimensions, such as plasmaspheric erosion and recovery, as well as plume formation. Storm time long-term density variations are consistent with expectations; short-term variations appear to be modulated by substorm activity or enhanced convection, an effect that requires further study together with multispacecraft in situ or imaging measurements. Investigating plasmaspheric refilling with the model, we find that it is not monotonic in time and is more complex than expected from previous studies, deserving further attention.

Tropical Storm Sam, Eastern Indian Ocean

NASA Image and Video Library

1990-01-20

STS032-80-036 (9-20 Jan. 1990) --- This oblique view of Tropical Storm Sam in the eastern Indian Ocean off the western coast of Australia was photographed with a 70mm camera by the astronauts. Tropical Storm Sam (known as Willy-Willy in Australia) was born in the eastern Indian Ocean near the islands of Timor and Sumba in Indonesia. The storm tracked southwestward attaining sustained winds in excess of 60 knots (70 miles per hour). Other than on Christmas Island and the Cocos (Keeling) Islands south of Java, and for strong swells along the western Australia coast, the storm had little impact on land areas. At the time this photograph was taken, the storm was beginning to dissipate in the south Indian Ocean. The eye of the storm is still visible near center, with the swirling bands of the storm propagating in a clockwise direction toward the center. Winds aloft have begun to shear the tops of thunderstorms associated with the storm, forming a high cirrus cloud cover over the center portions of the storm. This picture was used by the crew at their January 30, 1990 Post-Flight Press Conference (PFPC).

Earth Science

NASA Image and Video Library

2004-09-11

This image hosts a look at the eye of Hurricane Ivan, one of the strongest hurricanes on record, as the storm topped the western Caribbean Sea on Saturday, September 11, 2004. The hurricane was photographed by astronaut Edward M. (Mike) Fincke from aboard the International Space Station (ISS) at an altitude of approximately 230 miles. At the time, the category 5 storm sustained winds in the eye of the wall that were reported at about 160 mph. Crew Earth Observations record Earth surface changes over time, as well as more fleeting events such as storms, floods, fires, and volcanic eruptions.

Study of pre-storm environment by using rawinsonde and satellite observations

NASA Technical Reports Server (NTRS)

Hung, R. J.; Tsao, Y. D.

1987-01-01

Rawinsonde and satellite remote sensing data were utilized to examine the prestorm environment and mechanisms for the initiation of four groups of severe storms. The storms in Altus, Oklahoma, Pampas, Texas, Bennett, Colorado, and Red River Valley, Oklahoma are described. The geographical distributions of the areas of high moisture concentration and variations of tropopause heights for the storm groups are analyzed. It is detected that in the area of a low-level high concentration of moisture, the local tropopause height is lowest at the time of the storm cloud formation and development, and the potential energy storage per unit areas for the overshootiong clouds penetrating above the tropopause is related to the intensity of the storms produced. Numerical cloud modeling was performed for the storms. The model data are compared with the satellite and rawinsonde observations, and it is noted that the data correlate well.

U.S. Energy Disruptions

EIA Publications

EIA tracks and reports on selected significant storms that impact or could potentially impact energy infrastructure. See past historical events reported or real-time storm tracking with energy infrastructure maps.

Florida Thunderstorms: A Faucet of Reactive Nitrogen to the Upper Troposphere

NASA Technical Reports Server (NTRS)

Ridley, B.; Ott, L.; Emmons, L.; Montzka, D.; Weinheimer, A.; Knapp, D.; Grahek, F.; Li, L.; Heymsfield, G.; McGill, M.

2004-01-01

During the NASA Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) enhanced mixing ratios of nitric oxide were measured in the anvils of thunderstorms and in clear air downwind of storm systems on flights of a Wl3-57F high-altitude aircraft. Mixing ratios greater than l0 - 20 times background were readily observed over distances of 25-120 km due to lightning activity. In many of the Florida storms deposition of NO occurred up to near the tropopause but major deposition usually occurred 1 - 2 km below the tropopause, or mostly within the visible anvil volume formed prior to storm decay. Observations from two storms of very different anvil size and electrical activity allowed estimates of the total mass of NO, vented to the middle and upper troposphere. Using the cloud-to ground (CG) flash accumulations from the National Lightning Detection Network, climatological intra-cloud (IC) to CG ratios, and assuming that CG and IC flashes were of equivalent efficiency for NO production, the ranges of production per flash for a moderate-sized and a large storm were (0.51 - 1.0) x l0(exp 26) and (2.3 - 3.1) x 10(exp 26) molecules NO/flash, respectively. Using the recently determined average global flash rate of 44 8, a gross extrapolation of these two storms to represent possible global annual production rates yield 1.6 - 3.2 and 7.3 - 9.9 Tg(N)/yr, respectively. If the more usual assumption is made that IC efficiency is l/l0th that of CG activity, the ranges of production for the moderate-sized and large storm were (1.3 - 2.7) x l0(exp 26) and (6.0 - 8.1) x l0(exp 26) molecules NO/CG flash, respectively. The estimates from the large storm may be high because there is indirect evidence that the IC/CG ratio was larger than would be derived from climatology. These two storms and others studied did not have flash rates that scaled as approx. H(sup 5) where H is the cloud top altitude. The observed CG flash accumulations and NO(x) mass production estimate for the month of July over the Florida area were compared with a representative 3D global Chemistry-Transport Model (CTMJ that uses the Price et al. lightning parameterization. For two land grid points representing the Florida peninsula the model compared well with the observations: CG flash rates were low by only a factor of approx. 2. When the model grid points included the coastal regions of Florida the flash accumulations were lower than observed by a factor of 3.4 - 4.6. It is recommended that models using the Price et al. parameterization allow any global coastal grid point to maintain the land rather than the marine flash rate parameterization. The convection in this CTM underestimated the actual cloud top heights over Florida by 1 - 2 km and thus the total lightning flash rates and the altitude range of reactive nitrogen deposition. Broad scale (20 - 120 km) median mixing ratios of NO within anvils over Florida were significantly larger than in storms previously investigated over Colorado and New Mexico.

The Storm Time Evolution of the Ionospheric Disturbance Plasma Drifts

NASA Astrophysics Data System (ADS)

Zhang, Ruilong; Liu, Libo; Le, Huijun; Chen, Yiding; Kuai, Jiawei

2017-11-01

In this paper, we use the C/NOFS and ROCSAT-1 satellites observations to analyze the storm time evolution of the disturbance plasma drifts in a 24 h local time scale during three magnetic storms driven by long-lasting southward IMF Bz. The disturbance plasma drifts during the three storms present some common features in the periods dominated by the disturbance dynamo. The newly formed disturbance plasma drifts are upward and westward at night, and downward and eastward during daytime. Further, the disturbance plasma drifts are gradually evolved to present significant local time shifts. The westward disturbance plasma drifts gradually migrate from nightside to dayside. Meanwhile, the dayside downward disturbance plasma drifts become enhanced and shift to later local time. The local time shifts in disturbance plasma drifts are suggested to be mainly attributed to the evolution of the disturbance winds. The strong disturbance winds arisen around midnight can constantly corotate to later local time. At dayside the westward and equatorward disturbance winds can drive the F region dynamo to produce the poleward and westward polarization electric fields (or the westward and downward disturbance drifts). The present results indicate that the disturbance winds corotated to later local time can affect the local time features of the disturbance dynamo electric field.

Trace fossils, sedimentary facies and parasequence architecture from the Lower Cretaceous Mulichinco Formation of Argentina: The role of fair-weather waves in shoreface deposits

NASA Astrophysics Data System (ADS)

Wesolowski, Lindsey J. N.; Buatois, Luis A.; Mángano, M. Gabriela; Ponce, Juan José; Carmona, Noelia B.

2018-05-01

Shorefaces can display strong facies variability and integration of sedimentology and ichnology provides a high-resolution model to identify variations among strongly storm-dominated (high energy), moderately storm-affected (intermediate energy), and weakly storm-affected (low energy) shoreface deposits. In addition, ichnology has proved to be of help to delineate parasequences as trace-fossil associations are excellent indicators of environmental conditions which typically change along the depositional profile. Shallow-marine deposits and associated ichnofaunas from the Mulichinco Formation (Valanginian, Lower Cretaceous) in Puerta Curaco, Neuquén Basin, western Argentina, were analyzed to evaluate stress factors on shoreface benthos and parasequence architecture. During storm-dominated conditions, the Skolithos Ichnofacies prevails within the offshore transition and lower shoreface represented by assemblages dominated by Thalassinoides isp. and Ophiomorpha irregulaire. Under weakly storm-affected conditions, the Cruziana Ichnofacies is recognized, characterized by assemblages dominated by Thalassinoides isp. and Gyrochorte comosa in the offshore transition, and by Gyrochorte comosa within the lower shoreface. Storm-influenced conditions yield wider ichnologic variability, showing elements of both ichnofacies. Storm influence on sedimentation is affected by both allogenic (e.g. tectonic subsidence, sea-level, and sediment influx) and autogenic (e.g. hydrodynamic) controls at both parasequence and intra-parasequence scales. Four distinct types of parasequences were recognized, strongly storm-dominated, moderately storm-affected, moderately storm-affected - strongly fair-weather reworked, and weakly storm-affected, categorized based on parasequence architectural variability derived from varying degrees of storm and fair-weather wave influence. The new type of shoreface described here, the moderately storm-affected - strongly fair-weather reworked shoreface, features storm deposits reworked thoroughly by fair-weather waves. During fair-weather wave reworking, elements of the Cruziana Ichnofacies are overprinted upon relict elements of the Skolithos Ichnofacies from previous storm induced deposition. This type of shoreface, commonly overlooked in past literature, expands our understanding of the sedimentary dynamics and stratigraphic architecture in a shoreface susceptible to various parasequence and intra-parasequence scale degrees of storm and fair-weather wave influence.

On the ionospheric impact of recent storm events on satellite-based augmentation systems in middle and low-latitude sectors

NASA Technical Reports Server (NTRS)

Komjathy, Attila; Sparks, Lawrence; Mannucci, Anthony J.; Pi, Xiaoqing

2003-01-01

The Ionospheric correction algorithms have been characterized extensively for the mid-latitude region of the ionosphere where benign conditions usually exist. The United States Federal Aviation Administration's (FAA) Wide Area Augmentation System (WAAS) for civil aircraft navigation is focused primarily on the Conterminous United States (CONUS). Other Satellite-based Augmentation Systems (SBAS) include the European Geostationary Navigation Overlay Service (EGNOS) and the Japanese Global Navigation Satellite System (MSAS). Researchers are facing a more serious challenge in addressing the ionospheric impact on navigation using SBAS in other parts of the world such as the South American region on India. At equatorial latitudes, geophysical conditions lead to the so-called Appleton-Hartree (equatorial) anomaly phenomenon, which results in significantly larger ionospheric range delays and range delay spatial gradients than is observed in the CONUS or European sectors. In this paper, we use GPS measurements of geomagnetic storm days to perform a quantitative assessment of WAAS-type ionospheric correction algorithms in other parts of the world such as the low-latitude Brazil and mid-latitude Europe. For the study, we access a world-wide network of 400+ dual frequency GPS receivers.

Ground penetrating radar and differential global positioning system data collected in April 2016 from Fire Island, New York

USGS Publications Warehouse

Forde, Arnell S.; Bernier, Julie C.; Miselis, Jennifer L.

2018-02-22

Researchers from the U.S. Geological Survey (USGS) conducted a long-term coastal morphologic-change study at Fire Island, New York, prior to and after Hurricane Sandy impacted the area in October 2012. The Fire Island Coastal Change project objectives include understanding the morphologic evolution of the barrier island system on a variety of time scales (months to centuries) and resolving storm-related impacts, post-storm beach response, and recovery. In April 2016, scientists from the USGS St. Petersburg Coastal and Marine Science Center conducted geophysical and sediment sampling surveys on Fire Island to characterize and quantify spatial variability in the subaerial geology with the goal of subsequently integrating onshore geology with other surf zone and nearshore datasets.  This report, along with the associated USGS data release, serves as an archive of ground penetrating radar (GPR) and post-processed differential global positioning system (DGPS) data collected from beach and back-barrier environments on Fire Island, April 6–13, 2016 (USGS Field Activity Number 2016-322-FA). Data products, including unprocessed GPR trace data, processed DGPS data, elevation-corrected subsurface profile images, geographic information system files, and accompanying Federal Geographic Data Committee metadata are available for download.

The joint return period analysis of natural disasters based on monitoring and statistical modeling of multidimensional hazard factors.

PubMed

Liu, Xueqin; Li, Ning; Yuan, Shuai; Xu, Ning; Shi, Wenqin; Chen, Weibin

2015-12-15

As a random event, a natural disaster has the complex occurrence mechanism. The comprehensive analysis of multiple hazard factors is important in disaster risk assessment. In order to improve the accuracy of risk analysis and forecasting, the formation mechanism of a disaster should be considered in the analysis and calculation of multi-factors. Based on the consideration of the importance and deficiencies of multivariate analysis of dust storm disasters, 91 severe dust storm disasters in Inner Mongolia from 1990 to 2013 were selected as study cases in the paper. Main hazard factors from 500-hPa atmospheric circulation system, near-surface meteorological system, and underlying surface conditions were selected to simulate and calculate the multidimensional joint return periods. After comparing the simulation results with actual dust storm events in 54years, we found that the two-dimensional Frank Copula function showed the better fitting results at the lower tail of hazard factors and that three-dimensional Frank Copula function displayed the better fitting results at the middle and upper tails of hazard factors. However, for dust storm disasters with the short return period, three-dimensional joint return period simulation shows no obvious advantage. If the return period is longer than 10years, it shows significant advantages in extreme value fitting. Therefore, we suggest the multivariate analysis method may be adopted in forecasting and risk analysis of serious disasters with the longer return period, such as earthquake and tsunami. Furthermore, the exploration of this method laid the foundation for the prediction and warning of other nature disasters. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of changing topography on coastal tides and storm surge: a historical perspective

NASA Astrophysics Data System (ADS)

Talke, Stefan; Jay, David; Helaire, Lumas; Familkhalili, Ramin

2016-11-01

Over decadal and century time scales, the topography of coastal harbors changes due to natural and anthropogenic factors. These changes alter the mass and momentum balances of incoming waves, producing measureable changes to tides and surge. Here we use recently recovered archival data, historic bathymetric charts, and numerical models to assess changes in multiple estuaries. In the Columbia River estuary, Ems estuary, and Cape Fear Estuary, channel deepening has increased the M2 tide between 10 to 100% since the 19th century, due to both reduced frictional effects and altered resonance. The bathymetric perturbations also affect the propagation of other long-period waves: in Wilmington (NC), the worst-case scenario CAT-5 storm surge is modeled to increase by 50% since 19th century conditions. Similarly, in New York harbor, the 10 year storm-tide level has outpaced sea-level rise by nearly 30 cm since 1850. In the Columbia River, reduced friction has decreased the river slope (reducing water levels), but also led to amplification of both tides and flood waves. Going forward, historical bathymetric change may provide a clue to the future effects of climate change and continued anthropogenic development. National Science Foundation; US Army Corp of Engineers.