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Sample records for weather variability tides

  1. Weather Variability, Tides, and Barmah Forest Virus Disease in the Gladstone Region, Australia

    PubMed Central

    Naish, Suchithra; Hu, Wenbiao; Nicholls, Neville; Mackenzie, John S.; McMichael, Anthony J.; Dale, Pat; Tong, Shilu

    2006-01-01

    In this study we examined the impact of weather variability and tides on the transmission of Barmah Forest virus (BFV) disease and developed a weather-based forecasting model for BFV disease in the Gladstone region, Australia. We used seasonal autoregressive integrated moving-average (SARIMA) models to determine the contribution of weather variables to BFV transmission after the time-series data of response and explanatory variables were made stationary through seasonal differencing. We obtained data on the monthly counts of BFV cases, weather variables (e.g., mean minimum and maximum temperature, total rainfall, and mean relative humidity), high and low tides, and the population size in the Gladstone region between January 1992 and December 2001 from the Queensland Department of Health, Australian Bureau of Meteorology, Queensland Department of Transport, and Australian Bureau of Statistics, respectively. The SARIMA model shows that the 5-month moving average of minimum temperature (β = 0.15, p-value < 0.001) was statistically significantly and positively associated with BFV disease, whereas high tide in the current month (β = −1.03, p-value = 0.04) was statistically significantly and inversely associated with it. However, no significant association was found for other variables. These results may be applied to forecast the occurrence of BFV disease and to use public health resources in BFV control and prevention. PMID:16675420

  2. Tides and Decadal Variability

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    2003-01-01

    This paper reviews the mechanisms by which oceanic tides and decadal variability in the oceans are connected. We distinguish between variability caused by tides and variability observed in the tides themselves. Both effects have been detected at some level. The most obvious connection with decadal timescales is through the 18.6-year precession of the moon's orbit plane. This precession gives rise to a small tide of the same period and to 18.6-year modulations in the phase and amplitudes of short-period tides. The 18.6-year "node tide" is very small, no more than 2 cm anywhere, and in sea level data it is dominated by the ocean's natural Variability. Some authors have naively attributed climate variations with periods near 19 years directly to the node tide, but the amplitude of the tide is too small for this mechanism to be operative. The more likely explanation (Loder and Garrett, JGR, 83, 1967-70, 1978) is that the 18.6-y modulations in short-period tides, especially h e principal tide M2, cause variations in ocean mixing, which is then observed in temperature and other climatic indicators. Tidally forced variability has also been proposed by some authors, either in response to occasional (and highly predictable) tidal extremes or as a nonlinear low-frequency oscillation caused by interactions between short-period tides. The former mechanism can produce only short-duration events hardly more significant than normal tidal ranges, but the latter mechanism can in principle induce low-frequency oscillations. The most recent proposal of this type is by Keeling and Whorf, who highlight the 1800-year spectral peak discovered by Bond et al. (1997). But the proposal appears contrived and should be considered, in the words of Munk et al. (2002), "as the most likely among unlikely candidates."

  3. Interannual and Intraseasonal Variability of the Diurnal Tide

    NASA Astrophysics Data System (ADS)

    Riggin, D. M.; Ortland, D. A.; Lieberman, R. S.; Oberheide, J.; Murayama, Y.; Hocking, W. K.; Vincent, R. A.; Reid, I. M.; Kumar, G. K.; Batista, P. P.; Clemesha, B. R.

    2013-12-01

    Temporal variations in the amplitude of the diurnal tide (DT) have been observed by radars with a seasonal dependence that is typically semiannual in the tropics. During some years the wind variation departs from the normal seasonal behavior with anomalously large amplitudes compared to most other years. This anomaly often takes the form of a greatly enhanced boreal spring equinoctal maximum. The boreal spring of 2008 is a example of this behavior. Diurnal amplitudes in the meridional winds are shown in the figure below for the first 6 months of 2008. Note that the diurnal tide undergoes a sharp increase in amplitude up to 80 ms-1 during this event. The characteristics of this event are diagnosed in a variety of global data sets. These include our own physics-based assimilation of SABER temperatures, and gridded analyses from the national weather services (NCAR/NCEP and ECMWF). Tidal amplitude variations are sometimes attributed to nonlinear interaction. However, this type of interaction would be expected to produce non-migrating tides, e.g., westward-2 or standing. SABER data show that the amplitude anomaly is mainly in the migrating DT. The global data sets allow us to explore properties of the anomaly, such as its origin, evolution in time, and associated momentum flux. In addition to this case study, we also investigate the general characteristics of DT interannual variability during the years of the SABER mission (2002-present). Diurnal tide momentum deposition plays a significant role in controlling the zonal mean wind in the mesosphere, We demonstrate its importance in driving the mesospheric semiannual oscillation (MSAO). Diurnal tide wind amplitudes in the meridional component observed at two radar sites, Rarotonga, Cook Islands (22.1°S, 159.8°W), and at Guanacaste, Costa Rica (10.3°N, 85.6°W).

  4. Observations and simulations of the ionospheric lunar tide: Seasonal variability

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.

    2014-07-01

    The seasonal variability of the ionospheric lunar tide is investigated using a combination of Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations and thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM) simulations. The present study focuses on the seasonal variability of the lunar tide in the ionosphere and its potential connection to the occurrence of stratosphere sudden warmings (SSWs). COSMIC maximum F region electron density (NmF2) and total electron content observations reveal a primarily annual variation of the ionospheric lunar tide, with maximum amplitudes occurring at low latitudes during December-February. Simulations of the lunar tide climatology in TIME-GCM display a similar annual variability as the COSMIC observations. This leads to the conclusion that the annual variability of the lunar tide in the ionosphere is not solely due to the occurrence of SSWs. Rather, the annual variability of the lunar tide in the ionosphere is generated by the seasonal variability of the lunar tide at E region altitudes. However, compared to the observations, the ionospheric lunar tide annual variability is weaker in the climatological simulations which is attributed to the occurrence of SSWs during the majority of the years included in the observations. Introducing a SSW into the TIME-GCM simulation leads to an additional enhancement of the lunar tide during Northern Hemisphere winter, increasing the lunar tide annual variability and resulting in an annual variability that is more consistent with the observations. The occurrence of SSWs can therefore potentially bias lunar tide climatologies, and it is important to consider these effects in studies of the lunar tide in the atmosphere and ionosphere.

  5. Solar Cycle Variability in Mean Thermospheric Composition and Temperature Induced by Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Jones, M., Jr.; Forbes, J. M.; Hagan, M. E.

    2015-12-01

    Vertically-propagating atmospheric thermal tides whose origins lie in Earth's lower atmosphere are now widely recognized as one of the dominant "meteorological" drivers of space weather. Many prior research efforts have focused on documenting and understanding the role that dissipating tides play in determining the longitudinal and seasonal variability associated with lower thermospheric winds, temperature, and constituent densities. However, considerably less attention has focused on understanding the potential solar cycle variability in the mean thermospheric state induced by the tides. In this paper we utilize the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), forced with observationally-based tides at the model lower boundary from the Climatological Tidal Model of the Thermosphere (CTMT, from Oberheide et al. [2011]), to elucidate how the dissipating tides induce variations of up to 30 K in the zonal-mean thermosphere temperature between solar minimum and maximum. Numerical experiments are performed for the month of September and for solar minimum, medium, and maximum conditions in order to quantify the solar cycle variability associated with the different terms in the thermodynamic energy, major and minor neutral constituent continuity equations. Our analysis indicates that solar cycle variability in neutral temperatures results from a combination of net eddy heat transport effects and tidal modulation of net nitric oxide (NO) cooling. The chemical and dynamical pathways through which dissipating tides affect mean NO cooling differently at solar minimum and maximum are diagnosed.

  6. Solar variability, weather, and climate

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Advances in the understanding of possible effects of solar variations on weather and climate are most likely to emerge by addressing the subject in terms of fundamental physical principles of atmospheric sciences and solar-terrestrial physis. The limits of variability of solar inputs to the atmosphere and the depth in the atmosphere to which these variations have significant effects are determined.

  7. Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

    NASA Astrophysics Data System (ADS)

    Hurwitz, Shaul; Sohn, Robert A.; Luttrell, Karen; Manga, Michael

    2014-03-01

    We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1-0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.

  8. Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

    USGS Publications Warehouse

    Hurwitz, Shaul; Sohn, Robert A.; Luttrell, Karen; Manga, Michael

    2014-01-01

    We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.

  9. Weather variability, climatic change, and soybean production

    SciTech Connect

    Thompson, L.M.

    1985-01-01

    A crop/weather model was used to determine the effect of changing climate and weather variability on soybean production in the Corn Belt. A cooling trend from the 1930s to the 1970s was accompanied by an upward trend in July plus August rainfall. There was decreased weather variability from the 1930s to 1973 and greatly increased weather variability after 1973. Improved weather from 1930 to 1972 increased soybean yields 3 bushels/acre. Higher intensity rainfalls increased in Illinois and Iowa after 1970.

  10. Earthquake Weather: Linking Seismicity to Changes in Barometric Pressure, Earth Tides, and Rainfall

    NASA Astrophysics Data System (ADS)

    West, J. D.; Garnero, E.; Shirzaei, M.

    2015-12-01

    It has been widely observed that earthquakes can be triggered due to changes in stress induced by the passage of surface waves from remote earthquakes. These stress changes are typically on the order of a few kiloPascals and occur over time spans of seconds. Less well investigated is the question of whether triggering of seismic activity can result from similar stress changes occurring over periods of hours or days due to changing barometric pressure, rainfall, and Earth tides. Past studies have shown a possible link between these stress sources and slow earthquakes in Taiwan (Hsu et al., 2015). Here, we investigate the relationship between seismicity and changing barometric pressure, Earth tides, and rainfall for four regions of the western United States where regional seismic networks provide high-quality seismic catalogs over relatively long time periods: Southern California, Northern California, the Pacific Northwest, and Utah. For each region we obtained seismic catalogs from January 2001 through September 2014 and acquired hourly data for barometric pressure and rainfall across the regions from the National Climatic Data Center. The vertical stress time series due to Earth tides was computed for the location of each weather station in the study areas. We summed the stresses from these 3 sources and looked for variations in seismicity correlated to the stress changes. We show that seismicity rates increase with increasing magnitude of stress change. In many cases the increase in seismicity is larger for reductions in vertical stress than it is for stress increases. We speculate that the dependency of seismic rate on combined vertical stress is acting through a combination of two mechanisms: (1) Reduced stresses reduce the normal force on faults, triggering failure in critically-stressed faults. (2) Increased stresses may similarly reduce the normal force on faults due to increases in pore pressure induced in the fault region.

  11. Modernization, weather variability, and vulnerability to famine.

    PubMed

    D'Alessandro, Simone

    2011-01-01

    This paper shows that under weather variability the transformation from a rural to an incomplete market economy can increase the vulnerability of peasants to famine. This can occur even if improvements in technology have raised agricultural productivity and made production less responsive to weather variability. Indeed, negative environmental shocks can produce a drop in wages that outweighs the increase in wages due to an equivalent positive environmental shock. Consequently, the amount of grain stored increases more slowly in good seasons than it decreases in bad ones. This paper gives new insights on the catastrophic effects produced by widespread droughts in India during the second half of the 19th century. Notwithstanding the introduction of new modes of production and the modernization of infrastructures, the interaction between environmental variability and new institutional arrangements might have contributed to increase the vulnerability of peasants to famine. PMID:22164874

  12. Assessing the temporal variability in extreme storm-tide time series for coastal flood risk assessment

    NASA Astrophysics Data System (ADS)

    Quinn, N.; Lewis, M.; Wadey, M. P.; Haigh, I. D.

    2014-08-01

    The probability of extreme storm-tide events has been extensively studied; however, the variability within the duration of such events and implications to flood risk is less well understood. This research quantifies such variability during extreme storm-tide events (the combined elevation of the tide, surge, and their interactions) at 44 national tide gauges around the UK. Extreme storm-tide events were sampled from water level measurements taken every 15 min between 1993 and 2012. At each site, the variability in elevation at each time step, relative to a given event peak, was quantified. The magnitude of this time series variability was influenced both by gauge location (and hence the tidal and nontidal residual characteristics) and the time relative to high water. The potential influence of this variability on coastal inundation was assessed across all UK gauge sites, followed by a detailed case study of Portsmouth. A two-dimensional hydrodynamic model of the Portsmouth region was used to demonstrate that given a current 1 in 200 year storm-tide event, the predicted number of buildings inundated differed by more than 30% when contrasting simulations forced with the upper and lower bounds of the observed time series variability. The results indicate that variability in the time series of the storm-tide event can have considerable influence upon overflow volumes, hence with implications for coastal flood risk assessments. Therefore, further evaluating and representing this uncertainty in future flood risk assessments is vital, while the envelopes of variability defined in this research provides a valuable tool for coastal flood modelers.

  13. Impact of weather variability on nitrate leaching

    NASA Astrophysics Data System (ADS)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  14. Variability of diurnal tides and planetary waves during November 1978-May 1979

    NASA Astrophysics Data System (ADS)

    Lieberman, R. S.; Oberheide, J.; Hagan, M. E.; Remsberg, E. E.; Gordley, L. L.

    2004-04-01

    Nonlinear interactions between stationary waves and the migrating tides have been proposed as possible sources of nonmigrating tides in the middle and upper atmosphere. The objective of this study is to increase observational support for these processes. We examine the evolution of stationary planetary waves and nonmigrating diurnal tides in the lower mesosphere during November 1978-May 1979, based on a newly released, version 6 of the Nimbus 7 LIMS dataset. Planetary wavenumber one is large and variable during the Northern hemisphere winter months, reaching peak amplitude in the lower mesosphere between 20 and 30 January. This behavior is accompanied by rapid amplification of nonmigrating diurnal tides with zonal wavenumbers zero and two. These components correspond to product waves generated by interaction between the migrating diurnal tide and the stationary wave. The westward traveling zonal wavenumber two diurnal tide is dominant at tropical latitudes, in accordance with theoretical studies. The correlation between the nonmigrating tide and stationary wavenumber one is highest when the stationary wave penetrates to subtropical latitudes.

  15. Barometric Tides from ECMWF Operational Analyses

    NASA Technical Reports Server (NTRS)

    Ray, R. D.; Ponte, R. M.

    2003-01-01

    The solar diurnal and semidiurnal tidal oscillations in surface pressure are extracted from the the operational analysis product of the European Centre for Medium Range Weather Forecasting (ECMWF). For the semidiurnal tide this involves a special temporal interpolation, following Van den Dool and colleagues. The resulting tides are compared with a ground truth tide dataset, a compilation of well-determined tide estimates deduced from long time series of station barometer measurements. These comparisons show that the ECMWF tides are significantly more accurate than the tides deduced from two other widely available reanalysis products. Spectral analysis of ECMWF pressure series shows that the tides consist of sharp central peaks with modulating sidelines at integer multiples of 1 cycle/year, superimposed on a broad cusp of stochastic energy. The integrated energy in the cusp dominates that of the sidelines. This complicates development of a simple model that can characterize the full temporal variability of the tides.

  16. On the Temporal Variability of Low-Mode Internal Tides in the Deep Ocean

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Zaron, E. D.

    2010-01-01

    In situ measurements of internal tides are typically characterized by high temporal variability, with strong dependence on stratification, mesoscale eddies, and background currents commonly observed. Thus, it is surprising to find phase-locked internal tides detectable by satellite altimetry. An important question is how much tidal variability is missed by altimetry. We address this question in several ways. We subset the altimetry by season and find only very small changes -- an important exception being internal tides in the South China Sea where we observe strong seasonal dependence. A wavenumber-domain analysis confirms that throughout most of the global ocean there is little temporal variability in altimetric internal-tide signals, at least in the first baroclinic mode, which is the mode that dominates surface elevation. The analysis shows higher order modes to be significantly more variable. The results of this study have important practical implications for the anticipated SWOT wide-swath altimeter mission, for which removal of internal tide signals is critical for observing non-tidal submesoscale phenomena.

  17. A Link between Variability of the Semidiurnal Tide and Planetary Waves in the Opposite Hemisphere

    NASA Technical Reports Server (NTRS)

    Smith, Anne K.; Pancheva, Dora V.; Mitchell, Nicholas J.; Marsh, Daniel R.; Russell, James M., III; Mlynczak, Martin G.

    2007-01-01

    Horizontal wind observations over four years from the meteor radar at Esrange (68 deg N) are analyzed to determine the variability of the semidiurnal tide. Simultaneous global observations of temperature and geopotential from the SABER satellite instrument are used to construct time series of planetary wave amplitudes and geostrophic mean zonal wind. During NH summer and fall, the temporal variability of the semidiurnal tide at Esrange is found to be well correlated with the amplitude of planetary wavenumber 1 in the stratosphere in high southern latitudes (i.e., in the opposite hemisphere). The correlations indicate that a significant part of the tidal variations at Esrange is due to dynamical interactions in the Southern Hemisphere. Other times of the year do not indicate a corresponding robust correlation pattern for the Esrange tides over multiple years.

  18. Estimating decadal variability in sea level from tide gauge records: An application to the North Sea

    NASA Astrophysics Data System (ADS)

    Frederikse, Thomas; Riva, Riccardo; Slobbe, Cornelis; Broerse, Taco; Verlaan, Martin

    2016-03-01

    One of the primary observational data sets of sea level is represented by the tide gauge record. We propose a new method to estimate variability on decadal time scales from tide gauge data by using a state space formulation, which couples the direct observations to a predefined state space model by using a Kalman filter. The model consists of a time-varying trend and seasonal cycle, and variability induced by several physical processes, such as wind, atmospheric pressure changes and teleconnection patterns. This model has two advantages over the classical least-squares method that uses regression to explain variations due to known processes: a seasonal cycle with time-varying phase and amplitude can be estimated, and the trend is allowed to vary over time. This time-varying trend consists of a secular trend and low-frequency variability that is not explained by any other term in the model. As a test case, we have used tide gauge data from stations around the North Sea over the period 1980-2013. We compare a model that only estimates a trend with two models that also remove intra-annual variability: one by means of time series of wind stress and sea level pressure, and one by using a two-dimensional hydrodynamic model. The last two models explain a large part of the variability, which significantly improves the accuracy of the estimated time-varying trend. The best results are obtained with the hydrodynamic model. We find a consistent low-frequency sea level signal in the North Sea, which can be linked to a steric signal over the northeastern part of the Atlantic.

  19. Winter variability in the western Gulf of Maine: Part 1: Internal tides

    NASA Astrophysics Data System (ADS)

    Brown, W. S.

    2011-09-01

    During the winter 1997-1998, a field program was conducted in Wilkinson Basin-western Gulf of Maine-as part of a study of winter convective mixing. The field program consisted of (1) Wilkinson basin-scale hydrographic surveys, (2) a tight three-mooring array with ˜100 m separations measured temperature and conductivity at rates of 2-15 min and (3) a single pair of upward/downward-looking pair acoustic Doppler current profiling (ADCP) instruments measured currents with 8 m vertical resolution over the 270 m water column in north-central Wilkinson basin at a rate of 10 min. The moored array measurements below the mixed layer (˜100 m depth) between 11 January and 6 February 1998 were dominated by a combination of the relatively strong semidiurnal external (depth-independent or barotropic) tide; upon which were superposed a weaker phase-locked semidiurnal internal tide and a very weak water column mean currents of about 1 cm/s southward or approximately across the local isobaths. The harmonic analysis of a vertical average of the relatively uniform ADCP velocities in the well-mixed upper 123 m of the water column, defined the external tidal currents which were dominated by a nearly rectilinear, across-isobath (326°T) M 2 semidiurnal tidal current of about 15 cm/s. The depth-dependent residual current field, which was created by subtracting the external tidal current, consisted of (1) clockwise-rotating semidiurnal internal tidal currents of about 5 cm/s below the mixed layer; (2) clockwise-rotating inertial currents; and (3) a considerably less energetic subtidal current variability. The results from both frequency-domain empirical orthogonal function and tidal harmonic analyses of the of isotherm displacement series at each of the three moorings in the 100 m array mutually confirm an approximate east-northeastward phase propagation of the dominant M 2 semidiurnal internal tide across Wilkinson Basin. Further investigation supports the idea that this winter internal

  20. M2 baroclinic tide variability modulated by the ocean circulation south of Japan

    NASA Astrophysics Data System (ADS)

    Varlamov, Sergey M.; Guo, Xinyu; Miyama, Toru; Ichikawa, Kaoru; Waseda, Takuji; Miyazawa, Yasumasa

    2015-05-01

    We analyze a concurrent simulation result of the ocean circulation and tidal currents using a data-assimilative ocean general circulation model covering the Western North Pacific with horizontal resolution of 1/36° to investigate possible interactions between them. Four sites of active M2 internal tide variability in open ocean (hot spots), such as Tokara Strait, Izu Ridge, Luzon Strait, and Ogasawara Ridge, are detected from both the satellite observation and the simulation. Energy cycle analysis of the simulated M2 baroclinic tide indicates two types of the hot spots: dissipation (Tokara Strait and Izu Ridge) and radiation (Luzon Strait and Ogasawara Ridge) dominant sites. Energy conversion from barotropic to baroclinic M2 tides at the hot spots is modulated considerably by the lower-frequency changes in the density field. Modulation at the two spots (Tokara Strait and Izu Ridge) is affected by the Kuroshio path variation together with the seasonal variation of the shallow thermocline. At the other two sites, influence from changes in the relatively deep stratification through the Kuroshio intrusion into South China Sea (Luzon Strat) and mesoscale eddy activity (Ogasawara Ridge) is dominant in the modulation.

  1. Impact of the winter North-Atlantic weather regimes on subtropical sea-surface height variability

    NASA Astrophysics Data System (ADS)

    Barrier, Nicolas; Treguier, Anne-Marie; Cassou, Christophe; Deshayes, Julie

    2013-09-01

    Interannual variability of subtropical sea-surface-height (SSH) anomalies, estimated by satellite and tide-gauge data, is investigated in relation to wintertime daily North-Atlantic weather regimes. Sea-level anomalies can be viewed as proxies for the subtropical gyre intensity because of the intrinsic baroclinic structure of the circulation. Our results show that the strongest correlation between SSH and weather regimes is found with the so-called Atlantic-Ridge (AR) while no significant values are obtained for the other regimes, including those related to the North Atlantic Oscillation (NAO), known as the primary actor of the Atlantic dynamics. Wintertime AR events are characterized by anticyclonic wind anomalies off Europe leading to a northward shift of the climatological wind-stress curl. The latter affects subtropical SSH annual variability by altered Sverdrup balance and ocean Rossby wave dynamics propagating westward from the African coast towards the Caribbean. The use of a simple linear planetary geostrophic model allows to quantify those effects and confirms the primary importance of the winter season to explain the largest part of SSH interannual variability in the Atlantic subtropical gyre. Our results open new perspectives in the comprehension of North-Atlantic Ocean variability emphasizing the role of AR as a driver of interannual variability at least of comparable importance to NAO.

  2. Ionosphere variability during the 2009 SSW: Influence of the lunar semidiurnal tide and mechanisms producing electron density variability

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Liu, H.-L.; Sassi, F.; Lei, J.; Chau, J. L.; Zhang, X.

    2014-05-01

    To investigate ionosphere variability during the 2009 sudden stratosphere warming (SSW), we present simulation results that combine the Whole Atmosphere Community Climate Model Extended version and the thermosphere-ionosphere-mesosphere electrodynamics general circulation model (TIME-GCM). The simulations reveal notable enhancements in both the migrating semidiurnal solar (SW2) and lunar (M2) tides during the SSW. The SW2 and M2 amplitudes reach ˜50 m s-1 and ˜40 m s-1, respectively, in zonal wind at E region altitudes. The dramatic increase in the M2 at these altitudes influences the dynamo generation of electric fields, and the importance of the M2 on the ionosphere variability during the 2009 SSW is demonstrated by comparing simulations with and without the M2. TIME-GCM simulations that incorporate the M2 are found to be in good agreement with Jicamarca Incoherent Scatter Radar vertical plasma drifts and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations of the maximum F region electron density. The agreement with observations is worse if the M2 is not included in the simulation, demonstrating that the lunar tide is an important contributor to the ionosphere variability during the 2009 SSW. We additionally investigate sources of the F region electron density variability during the SSW. The primary driver of the electron density variability is changes in electric fields. Changes in meridional neutral winds and thermosphere composition are found to also contribute to the electron density variability during the 2009 SSW. The electron density variability for the 2009 SSW is therefore not solely due to variability in electric fields as previously thought.

  3. Radar observations of the diurnal tide in the tropical mesosphere-lower thermosphere region: Longitudinal variabilities

    NASA Astrophysics Data System (ADS)

    Gurubaran, S.; Rajaram, R.; Nakamura, T.; Tsuda, T.; Riggin, D.; Vincent, R. A.

    2009-04-01

    Significant attention is being paid in recent times by several observational and modeling studies to quantify the spatial and temporal variabilities of diurnal tide in the mesosphere and lower thermosphere (MLT) region. These variabilities are ascribed to spatial and temporal variations in the tidal forcing or interactions between the propagating tides and background wind, planetary waves or gravity waves. The present work makes use of simultaneous ground-based radar wind observations of different durations from five equatorial/low latitude sites in the Indian, Indonesian and Pacific sectors: Tirunelveli (8.7°N, 77.8°E), Jakarta (6.4°S, 106.7°E), Pontianak (0.03°N, 109°E), Kauai (22°N, 160°W) and Christmas Island (2°N, 157°W). This study delineates the longitudinal differences in the tidal characteristics in (i) interannual time scales over Tirunelveli and Kauai during 1993-2002, (ii) seasonal time scales over Christmas Island, Jakarta and Tirunelveli for the years 1993-1997 and (iii) shorter than seasonal time scales over Christmas Island, Pontianak and Tirunelveli during 1996-1997. An important observational feature noticed in this work is the differing behavior of the long-term tidal fields over Tirunelveli and Kauai. The monthly tidal amplitudes over Tirunelveli reveal a strong QBO signature whereas a similar, strong QBO signal could not be traced in the long-term observations from Kauai.

  4. Sea-level variability in the Mediterranean Sea from altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Bonaduce, A.; Pinardi, N.; Oddo, P.; Spada, G.; Larnicol, G.

    2016-02-01

    Sea-level variability in the Mediterranean Sea was investigated by means of in-situ (tide-gauge) and satellite altimetry data over a period spanning two decades (from 1993 to 2012). The paper details the sea-level variations during this time period retrieved from the two data sets. Mean sea-level (MSL) estimates obtained from tide-gauge data showed root mean square differences (RMSDs) in the order of 40-50 % of the variance of the MSL signal estimated from satellite altimetry data, with a dependency on the number and quality of the in-situ data considered. Considering the individual time-series, the results showed that coastal tide-gauge and satellite sea-level signals are comparable, with RMSDs that range between 2.5 and 5 cm and correlation coefficients up to the order of 0.8. A coherence analysis and power spectra comparison showed that two signals have a very similar energetic content at semi-annual temporal scales and below, while a phase drift was observed at higher frequencies. Positive sea-level linear trends for the analysis period were estimated for both the mean sea-level and the coastal stations. From 1993 to 2012, the mean sea-level trend (2.44± 0.5 mm year^{-1} ) was found to be affected by the positive anomalies of 2010 and 2011, which were observed in all the cases analysed and were mainly distributed in the eastern part of the basin. Ensemble empirical mode decomposition showed that these events were related to the processes that have dominant periodicities of ˜ 10 years, and positive residual sea-level trend were generally observed in both data-sets. In terms of mean sea-level trends, a significant positive sea-level trend (> 95 %) in the Mediterranean Sea was found on the basis of at least 15 years of data.

  5. The variability of nonmigrating tides detected from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Wan, Weixing; Ren, Zhipeng; Liu, Libo; Ning, Baiqi

    2015-12-01

    This paper deals with the variability of the nonmigrating tides detected from the observation of the SABER instrument on board the TIMED satellite during the 11 year solar period from 2002 to 2012. The longitudinal wave number spectra with 1 day resolution were first estimated from the temperature data measured at the MLT altitudes (70-110 km) and at the lower midlatitudes and low latitudes (between ±45°). Then we used the wave number 4 component to obtain the nonmigrating tides in which the dominant component DE3 was further analyzed in detail. We found that the properties of the spatial distribution and large time scale variation of the DE3 component are similar to those of the previous works, which used the interpolated data with 2 month resolution. These properties are that the DE3 component occurs mainly at the low latitudes within ±30° and at the altitudes from 90 to 110 km; the tidal amplitude is larger during boreal summer and early autumn, smaller in spring and almost tends to disappear in winter; the component is slightly stronger during the eastward wind QBO phase than the westward phase. Practically, the higher-resolution data were used to reveal the day-to-day variability of the DE3 component. It is found that (1) the variability occurs mainly at the altitudes from 100 to 110 km with a peak at 106 km; (2) it is strong at the low latitudes and peaks around the equator, as well, slightly stronger in the Southern Hemisphere than in northern one; (3) it is considerably larger around solstitial months than equinoctial months; and (4) it would not experience an obvious interannual variation. The day-to-day variability of the DE3 component may be explained by the variance of the absolute amplitudes and the contribution of the wave phases, and the later seems to play more important role.

  6. The variability of nonmigrating tides detected from TIMED/SABER observations

    NASA Astrophysics Data System (ADS)

    Li, Xing; Liu, Libo; Ning, Baiqi; Ren, Zhipeng; Wan, Weixing

    2016-07-01

    This work deals with the variability of the nonmigrating tides detected from the observation of the SABER instrument on board the TIMED satellite during the 11 year solar period from 2002 to 2012. The longitudinal wave number spectra with 1 day resolution were first estimated from the temperature data measured at the MLT altitudes (70-110 km) and at the lower midlatitudes and low latitudes (between ±±45°°). Then we used the wave number 4 component to obtain the nonmigrating tides in which the dominant component DE3 was further analyzed in detail. We found that the properties of the spatial distribution and large time scale variation of the DE3 component are similar to those of the previous works, which used the interpolated data with 2 month resolution. These properties are that the DE3 component occurs mainly at the low latitudes within ±30° and at the altitudes from 90 to 110 km; the tidal amplitude is larger during boreal summer and early autumn, smaller in spring and almost tends to disappear in winter; the component is slightly stronger during the eastward wind QBO phase than the westward phase. Practically, the higher-resolution data were used to reveal the day-to-day variability of the DE3 component. It is found that (1) the variability occurs mainly at the altitudes from 100 to 110 km with a peak at 106 km; (2) it is strong at the low latitudes and peaks around the equator, as well, slightly stronger in the Southern Hemisphere than in northern one; (3) it is considerably larger around solstitial months than equinoctial months; and (4) it would not experience an obvious interannual variation. The day-to-day variability of the DE3 component may be explained by the variance of the absolute amplitudes and the contribution of the wave phases, and the later seems to play more important role.

  7. On the variability of Pacific Ocean tides at seasonal to decadal time scales: Observed vs modelled

    NASA Astrophysics Data System (ADS)

    Devlin, Adam Thomas

    forward in time to the predicted sea level in 2100. Results suggest that stations with large positive combined A-TATs produce total water levels that are greater than those predicted by an increase in MSL alone, increasing the chances of high-water events. Part II examines the mechanisms behind the yearly (TAT) variability in the Western Tropical Pacific Ocean. Significant amplitude TATs are found at more than half of 26 gauges for each of the two strongest tidal constituents, K1 (diurnal) and M2 (semidiurnal). For the lesser constituents analyzed (O1 and S2), significant trends are observed at ten gauges. Part III analyzes the seasonal behavior of tides (STATs) at twenty tide gauges in the Southeast Asian waters, which exhibit variation by 10 -- 30% of mean tidal amplitudes. A barotropic ocean tide model that considers the seasonal effects of MSL, stratification, and geostrophic and Ekman velocity is used to explain the observed seasonal variability in tides due to variations in monsoon-influenced climate forcing, with successful results at about half of all gauges. The observed changes in tides are best explained by the influence of non-tidal velocities (geostrophic and Ekman), though the effect of changing stratification is also an important secondary causative mechanism. From the results of these surveys and investigations, it is concluded that short-term fluctuations in MSL and tidal properties at multiple time scales may be as important in determining the state of future water levels as the long-term trends. Global explanations for the observed tidal behavior have not been found in this study; however, significant regional explanations are found at the yearly time scale in the Solomon Sea, and at the seasonal time scale in Southeast Asia. It is likely that tidal sensitivity to annual and seasonal variations in MSL at other locations also are driven by locally specific processes, rather than factors with basin-wide coherence. (Abstract shortened by ProQuest.).

  8. Intraannual variability of tides in the thermosphere from model simulations and in situ satellite observations

    NASA Astrophysics Data System (ADS)

    Häusler, K.; Hagan, M. E.; Forbes, J. M.; Zhang, X.; Doornbos, E.; Bruinsma, S.; Lu, G.

    2015-01-01

    In this paper, we provide insights into limitations imposed by current satellite-based strategies to delineate tidal variability in the thermosphere, as well as the ability of a state-of-the-art model to replicate thermospheric tidal determinations. Toward this end, we conducted a year-long thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (TIME-GCM) simulation for 2009, which is characterized by low solar and geomagnetic activity. In order to account for tropospheric waves and tides propagating upward into the ˜30-400 km model domain, we used 3-hourly MERRA (Modern-Era Retrospective Analysis for Research and Application) reanalysis data. We focus on exospheric tidal temperatures, which are also compared with 72 day mean determinations from combined Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellite observations to assess the model's capability to capture the observed tidal signatures and to quantify the uncertainties associated with the satellite exospheric temperature determination technique. We found strong day-to-day tidal variability in TIME-GCM that is smoothed out when averaged over as few as ten days. TIME-GCM notably overestimates the 72 day mean eastward propagating tides observed by CHAMP/GRACE, while capturing many of the salient features of other tidal components. However, the CHAMP/GRACE tidal determination technique only provides a gross climatological representation, underestimates the majority of the tidal components in the climatological spectrum, and moreover fails to characterize the extreme variability that drives the dynamics and electrodynamics of the ionosphere-thermosphere system. A multisatellite mission that samples at least six local times simultaneously is needed to provide this quantification.

  9. Low frequency Sea Level Variability: correlation between altimetry and tide gauges in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Bonaduce, A.; Pinardi, N.

    2012-04-01

    Sea level variability in the Mediterranean Sea over the decadal time scale is studied using a combination of sea level and in-situ observations. A method to decompose the different sea level signals for tide gauges and altimetry is proposed, so that a coherent comparison between the two measurements is possible. The steric component and the atmospheric pressure contribution (inverse barometer) are filtered in order to look at sea level changes over decadal time scales. Low frequency sea level from tide gauges data is found to be representative of a large scale signal and results to be comparable, along all the basin, with satellite altimetry data. In particular the two signals are better correlated in the areas where the continental shelf is extended, such as the northern Adriatic. The same occurs in the case where the tide gauge station is located on an island, such as Malta, where the station is representative of the open ocean sea level signal. Moving towards the Levantin basin, the shelves extension generally decrease and the two data sets tend to be less correlated even if still correlated positively with a root mean square error lower than 5 cm (Hadera, Israel). Looking at the sea level trend, a positive trend of 2.15 ± 0.7 mm yr -1 is observed in the Mediterranean basin considering satellite altimetry during the period from 1993 to 2010 . Glacial Isostatic Adjustment (GIA) has been considered correcting sea level data with ICE-5G model data. This value represent just and index of the sea level changes occurring at basin scale. The basin presents a marked trend spatial variability, mainly characterized by strong positive trends in the shelves areas and negative trends in the Ionian sea, due to a strong change in the circulation in this basin. The variability of the trend values as a function of the number of years considered is such that at least 15 years of data are needed in order to obtain a significant and stable positive trend. The total lack of in

  10. Weather variability and adaptive management for rangeland restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inherent weather variability in upland rangeland systems requires relatively long-term goal setting, and contingency planning for partial success or failure in any given year. Rangeland plant communities are dynamic systems and successional planning is essential for achieving and maintaining system...

  11. Understanding Space Weather: The Sun as a Variable Star

    NASA Technical Reports Server (NTRS)

    Strong, Keith; Saba, Julia; Kucera, Therese

    2012-01-01

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

  12. Understanding Space Weather: The Sun as a Variable Star

    NASA Technical Reports Server (NTRS)

    Strong, Keith; Saba, Julia; Kucera, Therese

    2011-01-01

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

  13. MV-WG: a new multi-variable weather generator

    NASA Astrophysics Data System (ADS)

    Fodor, Nándor; Dobi, Ildikó; Mika, János; Szeidl, László

    2010-08-01

    This paper presents a new stochastic multi-variable weather generator (MV-WG) and compares its performance with LARS-WG version 4.0. Daily data of 109 meteorological stations from a North American database were used in a twofold comparison of the two generators: (1) the capability of reproducing the mean and variance of annual, seasonal and monthly values, and (2) the capability of reproducing extreme weather events were compared. Both generators did very well on imitating the mean and the variance of the monthly values of the investigated variables, but both showed a more moderate performance as far as the generation of extreme events was concerned. The three-parameter Weibull function, which is first introduced in MV-WG, was found to be a powerful tool to describe not only the distribution of the daily precipitation amounts, but also the distribution of dry and wet spell lengths, as well.

  14. Sea-level variability in tide-gauge and geological records: An empirical Bayesian analysis (Invited)

    NASA Astrophysics Data System (ADS)

    Kopp, R. E.; Hay, C.; Morrow, E.; Mitrovica, J. X.; Horton, B.; Kemp, A.

    2013-12-01

    Sea level varies at a range of temporal and spatial scales, and understanding all its significant sources of variability is crucial to building sea-level rise projections relevant to local decision-making. In the twentieth-century record, sites along the U.S. east coast have exhibited typical year-to-year variability of several centimeters. A faster-than-global increase in sea-level rise in the northeastern United States since about 1990 has led some to hypothesize a 'sea-level rise hot spot' in this region, perhaps driven by a trend in the Atlantic Meridional Overturning Circulation related to anthropogenic climate change [1]. However, such hypotheses must be evaluated in the context of natural variability, as revealed by observational and paleo-records. Bayesian and empirical Bayesian statistical approaches are well suited for assimilating data from diverse sources, such as tide-gauges and peats, with differing data availability and uncertainties, and for identifying regionally covarying patterns within these data. We present empirical Bayesian analyses of twentieth-century tide gauge data [2]. We find that the mid-Atlantic region of the United States has experienced a clear acceleration of sea level relative to the global average since about 1990, but this acceleration does not appear to be unprecedented in the twentieth-century record. The rate and extent of this acceleration instead appears comparable to an acceleration observed in the 1930s and 1940s. Both during the earlier episode of acceleration and today, the effect appears to be significantly positively correlated with the Atlantic Multidecadal Oscillation and likely negatively correlated with the North Atlantic Oscillation [2]. The Holocene and Common Era database of geological sea-level rise proxies [3,4] may allow these relationships to be assessed beyond the span of the direct observational record. At a global scale, similar approaches can be employed to look for the spatial fingerprints of land ice

  15. Comparison Between Radar and Automatic Weather Station Refractivity Variability

    NASA Astrophysics Data System (ADS)

    Hallali, Ruben; Dalaudier, Francis; Parent du Chatelet, Jacques

    2016-08-01

    Weather radars measure changes in the refractive index of air in the atmospheric boundary layer. The technique uses the phase of signals from ground targets located around the radar to provide information on atmospheric refractivity related to meteorological quantities such as temperature, pressure and humidity. The approach has been successfully implemented during several field campaigns using operational S-band radars in Canada, UK, USA and France. In order to better characterize the origins of errors, a recent study has simulated temporal variations of refractivity based on Automatic Weather Station (AWS) measurements. This reveals a stronger variability of the refractivity during the summer and in the afternoon when the refractivity is the most sensitive to humidity, probably because of turbulence close to the ground. This raises the possibility of retrieving information on the turbulent state of the atmosphere from the variability in radar refractivity. An analysis based on a 1-year dataset from the operational C-band radar at Trappes (near Paris, France) and AWS refractivity variability measurements was used to measure those temporal and spatial variabilities. Particularly during summer, a negative bias increasing with range is observed between radar and AWS estimations, and is well explained by a model based on Taylor's hypotheses. The results demonstrate the possibility of establishing, depending on season, a quantitative and qualitative link between radar and AWS refractivity variability that reflects low-level coherent turbulent structures.

  16. Comparison Between Radar and Automatic Weather Station Refractivity Variability

    NASA Astrophysics Data System (ADS)

    Hallali, Ruben; Dalaudier, Francis; Parent du Chatelet, Jacques

    2016-03-01

    Weather radars measure changes in the refractive index of air in the atmospheric boundary layer. The technique uses the phase of signals from ground targets located around the radar to provide information on atmospheric refractivity related to meteorological quantities such as temperature, pressure and humidity. The approach has been successfully implemented during several field campaigns using operational S-band radars in Canada, UK, USA and France. In order to better characterize the origins of errors, a recent study has simulated temporal variations of refractivity based on Automatic Weather Station (AWS) measurements. This reveals a stronger variability of the refractivity during the summer and in the afternoon when the refractivity is the most sensitive to humidity, probably because of turbulence close to the ground. This raises the possibility of retrieving information on the turbulent state of the atmosphere from the variability in radar refractivity. An analysis based on a 1-year dataset from the operational C-band radar at Trappes (near Paris, France) and AWS refractivity variability measurements was used to measure those temporal and spatial variabilities. Particularly during summer, a negative bias increasing with range is observed between radar and AWS estimations, and is well explained by a model based on Taylor's hypotheses. The results demonstrate the possibility of establishing, depending on season, a quantitative and qualitative link between radar and AWS refractivity variability that reflects low-level coherent turbulent structures.

  17. Short-term nonmigrating tide variability in the mesosphere, thermosphere, and ionosphere

    NASA Astrophysics Data System (ADS)

    Pedatella, N. M.; Oberheide, J.; Sutton, E. K.; Liu, H.-L.; Anderson, J. L.; Raeder, K.

    2016-04-01

    The intraseasonal variability of the eastward propagating nonmigrating diurnal tide with zonal wave number 3 (DE3) during 2007 in the mesosphere, ionosphere, and thermosphere is investigated using a whole atmosphere model reanalysis and satellite observations. The atmospheric reanalysis is based on implementation of data assimilation in the Whole Atmosphere Community Climate Model (WACCM) using the Data Assimilation Research Testbed (DART) ensemble Kalman filter. The tidal variability in the WACCM+DART reanalysis is compared to the observed variability in the mesosphere and lower thermosphere (MLT) based on the Thermosphere Ionosphere Mesosphere Energetics Dynamics satellite Sounding of the Atmosphere using Broadband Emission Radiometry (TIMED/SABER) observations, in the ionosphere based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations, and in the upper thermosphere (˜475 km) based on Gravity Recovery and Climate Experiment (GRACE) neutral density observations. To obtain the short-term DE3 variability in the MLT and upper thermosphere, we apply the method of tidal deconvolution to the TIMED/SABER observations and consider the difference in the ascending and descending longitudinal wave number 4 structure in the GRACE observations. The results reveal that tidal amplitude changes of 5-10 K regularly occur on short timescales (˜10-20 days) in the MLT. Similar variability occurs in the WACCM+DART reanalysis and TIMED/SABER observations, demonstrating that the short-term variability can be captured in whole atmosphere models that employ data assimilation and in observations by the technique of tidal deconvolution. The impact of the short-term DE3 variability in the MLT on the ionosphere and thermosphere is also clearly evident in the COSMIC and GRACE observations. Analysis of the troposphere forcing in WACCM+DART and simulations of the Global Scale Wave Model (GSWM) show that the short-term DE3 variability in the MLT is

  18. Dynamic and Regression Modeling of Ocean Variability in the Tide-Gauge Record at Seasonal and Longer Periods

    NASA Technical Reports Server (NTRS)

    Hill, Emma M.; Ponte, Rui M.; Davis, James L.

    2007-01-01

    Comparison of monthly mean tide-gauge time series to corresponding model time series based on a static inverted barometer (IB) for pressure-driven fluctuations and a ocean general circulation model (OM) reveals that the combined model successfully reproduces seasonal and interannual changes in relative sea level at many stations. Removal of the OM and IB from the tide-gauge record produces residual time series with a mean global variance reduction of 53%. The OM is mis-scaled for certain regions, and 68% of the residual time series contain a significant seasonal variability after removal of the OM and IB from the tide-gauge data. Including OM admittance parameters and seasonal coefficients in a regression model for each station, with IB also removed, produces residual time series with mean global variance reduction of 71%. Examination of the regional improvement in variance caused by scaling the OM, including seasonal terms, or both, indicates weakness in the model at predicting sea-level variation for constricted ocean regions. The model is particularly effective at reproducing sea-level variation for stations in North America, Europe, and Japan. The RMS residual for many stations in these areas is 25-35 mm. The production of "cleaner" tide-gauge time series, with oceanographic variability removed, is important for future analysis of nonsecular and regionally differing sea-level variations. Understanding the ocean model's strengths and weaknesses will allow for future improvements of the model.

  19. Aerosol variability and weather regimes over the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Nabat, Pierre; Somot, Samuel; Mallet, Marc; Michou, Martine

    2015-04-01

    The Mediterranean region is characterized by the accumulation of aerosols from different sources: industrial and urban aerosols from Europe and North African towns, biomass burning, from Eastern Europe, dust aerosols from Africa, and marine particles from the sea. These aerosols show a strong spatio-temporal variability and a resulting large variety in aerosol optical properties over this basin. Maximal aerosol loads are observed in spring and summer, namely in the dry season favouring a longer residence time for atmospheric aerosols. Besides, dust outbreaks characterized by large plumes of Saharan desert dust particles, are more frequent in this season. This study realized in the framework of the ChArMEx initiative aims at explaining this aerosol variability and the relationship between aerosol loads and weather conditions. We consider here an approach based on weather regimes and regional modeling. From a multi-year (1979-2013) regional simulation carried out with the ALADIN-climate model (50 km resolution, ERA-Interim forcing) including an interactive aerosol scheme for the main species present in this region (desert dust, sea-salt, sulfates and carbonaceous particles), we have identified typical synoptic conditions that favour high aerosol loads over the Mediterranean, or on the contrary that are opposed to these high aerosol loads. These weather regimes are based on a statistical method of automated classification realized from surface pressure data. They are also related to the North Atlantic Oscillation (NAO). In this work, we characterize the presence of the different aerosol types over the Mediterranean for each weather regime, as well as their effects on climate. Thus, anomalies in the occurrence of the regimes favourable to high aerosol loads could explain the frequent dust outbreaks observed during the ChArMEx campaigns in 2012 and 2013.

  20. Tide generator

    SciTech Connect

    Feltenberger, B.D.

    1981-06-16

    A tidewater power system consisting of a high tide reservoir and a low tide reservoir. The high tide reservoir has an inlet adapted to be supported at high tide level and an outlet with a water wheel and generator between the outlet of the high tide reservoir and the low tide reservoir. The low tide reservoir has an outlet at the low tide level. The outlet from the high tide reservoir is adjustable to control the flow rate and the high tide reservoir can be closed at high tide to retain water for use over a period of time.

  1. The Space Weather and Ultraviolet Solar Variability (SWUSV) Microsatellite Mission

    NASA Astrophysics Data System (ADS)

    Damé, Luc

    2013-05-01

    We present the ambitions of the SWUSV (Space Weather and Ultraviolet Solar Variability) Microsatellite Mission that encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (Lyman-Alpha and Herzberg continuum imaging); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 20 nm, plus Lyman-Alpha and the CN bandhead); (3) simultaneous radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The paper briefly outlines the mission and describes the five proposed instruments of the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200-220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2017-2018.

  2. The Space Weather and Ultraviolet Solar Variability (SWUSV) Microsatellite Mission

    PubMed Central

    Damé, Luc; Meftah, Mustapha; Hauchecorne, Alain; Keckhut, Philippe; Sarkissian, Alain; Marchand, Marion; Irbah, Abdenour; Quémerais, Éric; Bekki, Slimane; Foujols, Thomas; Kretzschmar, Matthieu; Cessateur, Gaël; Shapiro, Alexander; Schmutz, Werner; Kuzin, Sergey; Slemzin, Vladimir; Urnov, Alexander; Bogachev, Sergey; Merayo, José; Brauer, Peter; Tsinganos, Kanaris; Paschalis, Antonis; Mahrous, Ayman; Khaled, Safinaz; Ghitas, Ahmed; Marzouk, Besheir; Zaki, Amal; Hady, Ahmed A.; Kariyappa, Rangaiah

    2013-01-01

    We present the ambitions of the SWUSV (Space Weather and Ultraviolet Solar Variability) Microsatellite Mission that encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (Lyman-Alpha and Herzberg continuum imaging); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 20 nm, plus Lyman-Alpha and the CN bandhead); (3) simultaneous radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The paper briefly outlines the mission and describes the five proposed instruments of the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200–220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2017–2018. PMID:25685424

  3. Temperature variability caused by internal tides in the coral reef ecosystem of Hanauma bay, Hawai'i

    NASA Astrophysics Data System (ADS)

    Smith, Katharine A.; Rocheleau, Greg; Merrifield, Mark A.; Jaramillo, Sergio; Pawlak, Geno

    2016-03-01

    Hanauma Bay Nature Preserve is a shallow bay (<30 m depth) on the island of O'ahu, Hawai'i, offshore of which tidal flow over deep ridge topography (500-1000 m depth) is known to generate semidiurnal frequency internal tides. A field experiment was conducted during March to June 2009 to determine whether the deep internal tides propagate shoreward to influence variability in temperature and currents in the bay environment. Temperature observations in the bay exhibit a diurnal cycle that is strongest near the surface (upper 10 m) and is associated with solar heating. In early summer (May-June), as the upper mixed layer warms and a shallow seasonal thermocline develops, temperature fluctuations in deeper bay waters (>15 m depth) become dominated by large semidiurnal variations (up to 2.7 °C) that are attributed to the internal tide. These temperature drops caused by the internal tide occur consistently twice a day under summer stratification at depths as shallow as 15 m, while smaller temperature drops (up to 1.8 °C) occur occasionally at 5 m. Although semidiurnal band temperatures vary seasonally, semidiurnal band currents exhibit similar magnitudes in spring and summer. This suggests that the weak temperature fluctuations in spring are due to the bay residing entirely in the upper mixed layer at this time of year, while internal tide energy continues to influence currents. Observations made along a cross-shore/vertical transect at the center of the bay with an autonomous underwater vehicle highlight the structure of cold intrusions that fill a large portion of the bay as well as the relationship between temperature, salinity, chlorophyll, and backscatter. Near-bottom, advective heat flux estimates at the mouth of the bay indicate that the internal tide tends to advect cold water into the bay primarily on the northeast side of the bay entrance, with cold water outflow on the opposite side. The observations highlight the role of the internal tide along with

  4. Quantifying storm tide risk in Fiji due to climate variability and change

    NASA Astrophysics Data System (ADS)

    McInnes, Kathleen L.; Walsh, Kevin J. E.; Hoeke, Ron K.; O'Grady, Julian G.; Colberg, Frank; Hubbert, Graeme D.

    2014-05-01

    Extreme sea level events due to tropical cyclone storm surge combined with astronomical tide (storm tides) severely impact Pacific Island communities and these impacts are expected to increase with projected sea level rise. However, these sea level extremes are not well characterised by available tide gauge records owing to the low frequency of occurrence of tropical cyclones, the sparse array of tide gauges and the short time frame over which many gauges in this region have been operating. In this study, a combined statistical/dynamical method for estimating storm tide risk is presented. Tropical cyclones in the Fiji region over the period 1969-2007 are characterised in a statistical model that represents cyclone frequency, intensity and movement. The statistical model is then used to develop a population of “synthetic” cyclones that provide boundary conditions to a hydrodynamic storm surge and tidal model. This Monte-Carlo method is applied to the coasts of the Fiji archipelago. It is found that storm tide risk is higher on the northwest coasts of both the southern and northern main islands Viti Levu and Vanua Levu, respectively. Modelling suggests that there is a greater tendency for higher storm surges to occur on southwest Viti Levu under El Niño and La Niña years compared with average years, but elsewhere on Viti Levu and Vanua Levu, there is a tendency for slightly lower storm surges in La Niña years. Imposing perturbations to the cyclone statistical model that represent projected tropical cyclone changes in intensity and frequency for mid to late 21st Century, leads to storm tide return period curves that are steeper such that sea levels associated with return periods of 200 years or more become higher, those with return periods of 50 years and less become lower and the 1-in-100 year heights are little changed. Projected changes in sea level are found to make the largest contribution to increased extreme sea level risk.

  5. Effects of tides, vertical discretization schemes and runoff variability on a pan-Arctic Ocean simulation.

    NASA Astrophysics Data System (ADS)

    Luneva, Maria; Holt, Jason; Harle, James; Liu, Hedong

    2013-04-01

    The results of a recently developed NEMO-shelf pan-Arctic Ocean model coupled with LIM2 ice model are presented. This pan Arctic model has a hybrid s-z vertical discretization with terrain following coordinates on the shelf, condensing towards the bottom and surface boundary layer, and partial step z-coordinates in the abyss. This allows (a) processes near the surface to be resolved (b) Cascading (shelf convection), which contributes to the formation of halocline and deep dense water, to be well reproduced; and (c) minimize pressure gradient errors peculiar to terrain following coordinates. Horizontal grid and topography corresponds to global NEMO -ORCA 0.25 model (which uses a tripolar grid) with seamed slit between the western and eastern parts. In the Arctic basin this horizontal resolution corresponds to 15-10km with 5-7 km in the Canadian Archipelago. The model uses the General Length Scale vertical turbulent mixing scheme with (K- ɛ) closure and Kantha and Clayson type structural functions. Smagorinsky type Laplacian diffusivity and viscosity are employed for the description of a horizontal mixing. Vertical Piecewise Parabolic Method has been implemented with the aim to reduce an artificial vertical mixing. Boundary conditions are taken from the 5-days mean output of NOCS version of the global ORCA-025 model and OTPS/tpxo7 for 9 tidal harmonics . For freshwater runoff we employed two different forcings: a climatic one, used in global ORCA-0.25 model, and a recently available data base from Dai and Trenberth (Feb2011) 1948-2007, which takes in account inter-annual variability and includes 1200 river guages for the Arctic ocean coast. The simulations have been performed for two intervals: 1978-1988 and 1997-2007. The model adequately reproduces the main features of dynamics, tides and ice volume/concentration. The analysis shows that the main effects of tides occur at the ice-water interface and bottom boundary layers due to mesoscale Ekman pumping , generated

  6. Understanding the link between large-scale climate variability and regional hydrologic variability using weather patterns as intermediate variables

    NASA Astrophysics Data System (ADS)

    Renard, Benjamin; Lall, Upmanu

    2013-04-01

    Climate naturally follows specific modes of variability, quantified by some climate indices (e.g. North Atlantic Oscillation NAO, Southern Oscillation Index SOI, Atlantic Multidecadal Oscillation AMO, etc.). These modes of variability are due to large-scale climatic processes affecting large areas, and whose temporal scales range from a few months to a few decades. The temporal variability of hydrological regimes depends on such modes of variability, as has been reported in several regions worldwide. However, this relationship is more difficult to observe in some other regions, for several possible reasons: (i) the large natural variability of hydrological regimes, especially in the extreme domain, might strongly restrict the ability to detect weak or moderate relationships; (ii) Standard modes of variability like the NAO, SOI, etc. might not be the most relevant for some regions. This presentation explores an approach which, instead of directly seeking links between large-scale climate variability and regional hydrologic variability, decomposes the problem into two transitive "sub-problems" involving weather patterns as intermediate variables. Weather patterns are used to describe the atmospheric situation over a region as a categorical variable. As region-specific indices, they are potentially more explanatory than larger-scale indices like the NAO or SOI to explain the regional variability of hydrologic regimes. Consequently, two probabilistic models are derived: (1) a model to predict the frequency of weather patterns using large-scale climate indices (NAO, SOI, etc.) as predictors; (2) a model to predict the regional distribution of some hydrologic variable (e.g. number of flood events) using the frequencies of weather patterns as predictors. A case study based on French flood data is used to illustrate the application of this approach. It shows that each sub-model has some predictive ability: for instance, the annual number of flood events can be predicted

  7. Solar cycle variability in mean thermospheric composition and temperature induced by atmospheric tides

    NASA Astrophysics Data System (ADS)

    Jones, M.; Forbes, J. M.; Hagan, M. E.

    2016-06-01

    In this paper we demonstrate that dissipation of upward propagating tides produces significant changes in the mean temperature of the thermosphere, ranging from +19 K at solar minimum to -15 K at solar maximum in the equatorial region. Our methodology consists of measuring the differential response of the thermosphere-ionosphere-electrodynamics general circulation model (TIE-GCM) under solar minimum and solar maximum conditions to constant tidal forcing at its 97 km lower boundary, as specified by the observationally based Climatological Tidal Model of the Thermosphere. Diagnosis of the model reveals that these changes are mainly driven by 5.3 μm nitric oxide (NO) cooling, which more efficiently cools the thermosphere at solar maximum. The main role of the tides is to modify the mean molecular oxygen densities ([O2]) through tidal-induced advective transport, which then lead to changes in NO densities through oxygen-nitrogen chemistry. Through tidal-induced changes in temperature and O, O2, and N2 densities, effects on the ionosphere are also quite substantial; tidal-induced modifications to zonal-mean F region peak electron densities (NmF2) are of order -10% at solar maximum and -30% at solar minimum in the equatorial region. Our results introduce an additional consideration when attributing long-term changes in thermospheric temperature and electron densities to CO2 cooling effects alone; that is, dissipation of upward propagating tides may constitute an additional element of global change in the ionosphere-thermosphere (IT) system.

  8. Climatology of diurnal tide and its long-term variability in the lower middle atmosphere over a tropical station

    NASA Astrophysics Data System (ADS)

    Kumar, P. Vinay; Dutta, Gopa; Mohammad, Salauddin; Rao, B. Venkateswara

    2016-07-01

    ECMWF reanalysis (ERA-interim) data of winds for two solar cycles (1991-2012) are harmonically analyzed to delineate the characteristics and variability of diurnal tide over a tropical site (13.5° N, 79.5° E). The diurnal cycle horizontal winds measured by Gadanki (13.5° N, 79.2° E) mesosphere-stratosphere-troposphere (MST) radar between May 2005 and April 2006 have been used to compute 24 h tidal amplitudes and phases and compared with the corresponding results obtained from ERA winds. The climatological diurnal tidal amplitudes and phases have been estimated from surface to ˜33 km using ERA interim data. The amplitudes and phases obtained in the present study are found to compare reasonably well with Global Scale Wave Model (GSWM-09). Diurnal tides show larger amplitudes in the lower troposphere below 5 km during summer and in the mid-stratosphere mainly during equinoctial months and early winter. Water vapor and convection in the lower troposphere are observed to play major roles in exciting 24-h tide. Correlations between diurnal amplitude and integrated water vapor and between diurnal amplitude and outgoing longwave radiation (OLR) are 0.59 and -0.34, respectively. Ozone mixing ratio correlates (ρ = 0.66) well with diurnal amplitude and shows annual variation in the troposphere whereas semi-annual variation is observed at stratospheric heights with stronger peaks in equinoctial months. A clear annual variation of diurnal amplitude is displayed in the troposphere and interannual variability becomes prominent in the stratosphere which could be partly due to the influence of equatorial stratospheric QBO. The influence of solar activity on diurnal oscillations is found to be insignificant.

  9. Variability of the internal tide on the southern Monterey Bay continental shelf and associated bottom boundary layer sediment transport

    NASA Astrophysics Data System (ADS)

    Rosenberger, Kurt J.; Storlazzi, Curt D.; Cheriton, Olivia M.

    2016-06-01

    A 6-month deployment of instrumentation from April to October 2012 in 90 m water depth near the outer edge of the mid-shelf mud belt in southern Monterey Bay, California, reveals the importance regional upwelling on water column density structure, potentially accounting for the majority of the variability in internal tidal energy flux across the shelf. Observations consisted of time-series measurements of water-column currents, temperature and salinity, and near-bed currents and suspended matter. The internal tide accounted for 15-25% of the water-column current variance and the barotropic tide accounted for up to 35%. The subtidal flow showed remarkably little shear and was dominated by the 7-14 day band, which is associated with relaxations in the dominant equatorward winds typical of coastal California in the spring and summer. Upwelling and relaxation events resulted in strong near-bed flows and accounted for almost half of the current stress on the seafloor (not accounting for wave orbital velocities), and may have driven along-shelf geostrophic flow during steady state conditions. Several elevated suspended particulate matter (SPM) events occurred within 3 m of the bed and were generally associated with higher, long-period surface waves. However, these peaks in SPM did not coincide with the predicted resuspension events from the modeled combined wave-current shear stress, indicating that the observed SPM at our site was most likely resuspended elsewhere and advected along-isobath. Sediment flux was almost equal in magnitude in the alongshore and cross-shore directions. Instances of wave-current shear stress that exceeded the threshold of resuspension for the silty-clays common at these water depths only occurred when near-bed orbital velocities due to long-period surface waves coincided with vigorous near-bed currents associated with the internal tide or upwelling/relaxation events. Thus upwelling/relaxation dynamics are primarily responsible for variability

  10. Variability of the internal tide on the southern Monterey Bay continental shelf and associated bottom boundary layer sediment transport

    USGS Publications Warehouse

    Rosenberger, Kurt; Storlazzi, Curt; Cheriton, Olivia

    2016-01-01

    A 6-month deployment of instrumentation from April to October 2012 in 90 m water depth near the outer edge of the mid-shelf mud belt in southern Monterey Bay, California, reveals the importance regional upwelling on water column density structure, potentially accounting for the majority of the variability in internal tidal energy flux across the shelf. Observations consisted of time-series measurements of water-column currents, temperature and salinity, and near-bed currents and suspended matter. The internal tide accounted for 15–25% of the water-column current variance and the barotropic tide accounted for up to 35%. The subtidal flow showed remarkably little shear and was dominated by the 7–14 day band, which is associated with relaxations in the dominant equatorward winds typical of coastal California in the spring and summer. Upwelling and relaxation events resulted in strong near-bed flows and accounted for almost half of the current stress on the seafloor (not accounting for wave orbital velocities), and may have driven along-shelf geostrophic flow during steady state conditions. Several elevated suspended particulate matter (SPM) events occurred within 3 m of the bed and were generally associated with higher, long-period surface waves. However, these peaks in SPM did not coincide with the predicted resuspension events from the modeled combined wave–current shear stress, indicating that the observed SPM at our site was most likely resuspended elsewhere and advected along-isobath. Sediment flux was almost equal in magnitude in the alongshore and cross-shore directions. Instances of wave–current shear stress that exceeded the threshold of resuspension for the silty-clays common at these water depths only occurred when near-bed orbital velocities due to long-period surface waves coincided with vigorous near-bed currents associated with the internal tide or upwelling/relaxation events. Thus upwelling/relaxation dynamics are primarily responsible for

  11. Global structure and seasonal variability of the migrating terdiurnal tide in the mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Yue, Jia; Xu, Jiyao; Chang, Loren C.; Wu, Qian; Liu, Han-Li; Lu, Xian; Russell, James

    2013-12-01

    The morphology of the migrating terdiurnal tide with zonal wavenumber 3 (TW3) in the mesosphere and lower thermosphere (MLT) is revealed using the TIMED satellite datasets from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and the TIMED Doppler Interferometer (TIDI) instruments from 2002 to 2009, as well as the Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM). The annual mean structures of the TW3 from the TIME-GCM clearly resemble the first real symmetric (3,3) Hough mode. The TW3 temperature and zonal wind components have three peaks at midlatitudes and near the equator, while the TW3 meridional wind components show four peaks at mid and low latitudes. These features are consistent with those resolved in SABER temperature and TIDI zonal wind above ~95 km. TW3 components in the TIME-GCM are stronger during winter and spring months at midlatitudes, which is in agreement with previous ground-based radar measurements. On the other hand, TW3 components of temperature, zonal and meridional winds from SABER and TIDI display different seasonal variations at different altitudes and latitudes. The results presented in this paper will provide an observational basis for further modeling study of terdiurnal tide impacts on the thermosphere and ionosphere.

  12. Cenozoic carbon cycle imbalances and a variable weathering feedback

    NASA Astrophysics Data System (ADS)

    Caves, Jeremy K.; Jost, Adam B.; Lau, Kimberly V.; Maher, Kate

    2016-09-01

    The long-term stability of Earth's climate and the recovery of the ocean-atmosphere system after carbon cycle perturbations are often attributed to a stabilizing negative feedback between silicate weathering and climate. However, evidence for the operation of this feedback over million-year timescales and in response to tectonic and long-term climatic change remains scarce. For example, the past 50 million years of the Cenozoic Era are characterized by long-term cooling and declining atmospheric CO2 (pCO2). During this interval, constant or decreasing carbon fluxes from the solid Earth to the atmosphere suggest that stable or decreasing weathering fluxes are needed to balance the carbon cycle. In contrast, marine isotopic proxies of weathering (i.e., 87Sr/86Sr, δ7 Li , and 187Os/188Os) are interpreted to reflect increasing weathering fluxes. Here, we evaluate the existence of a negative feedback by reconstructing the imbalance in the carbon cycle during the Cenozoic using the surface inventories of carbon and alkalinity. Only a sustained 0.25-0.5% increase in silicate weathering is necessary to explain the long-term decline in pCO2 over the Cenozoic. We propose that the long-term decrease in pCO2 is due to an increase in the strength of the silicate weathering feedback (i.e., the constant of proportionality between the silicate weathering flux and climate), rather than an increase in the weathering flux. This increase in the feedback strength, which mirrors the marine isotope proxies, occurs as transient, <1 million year increases in the weathering flux, which remove CO2. As runoff and temperature decline in response, the integrated weathering flux over >1 million year timescales remains invariant to match the long-term inputs of carbon. Over the Cenozoic, this results in stable long-term weathering fluxes even as pCO2 decreases. We attribute increasing feedback strength to a change in the type and reactivity of rock in the weathering zone, which collectively has

  13. ASSESSMENT OF THE POTENTIAL EFFECTS OF CLIMATE CHANGE AND CLIMATE VARIABILITY ON WEATHER-RELATED MORBIDITY

    EPA Science Inventory

    The potential effects of climate change and climate variability on weather-related morbidity are assessed. Heat-related and cold-related morbidity in children are analyzed. The impact of inclement weather on accidental injuries is evaluated. The relationship of violent crime to w...

  14. High-latitude oceanic variability associated with the 18. 6-year nodal tide

    SciTech Connect

    Royer, T.C. )

    1993-03-15

    Ocean temperatures in the upper 250 m in the northern North Pacific (60[degree]N, 149[degree]W) increased by more than 1[degree]C from 1972 to 1986 but are now decreasing. Subsurface temperature anomalies are well correlated ([approx] 0.58) with the air temperature anomalies at Sitka, Alaska; hence the coastal air temperatures can be used as a proxy data set to extend the ocean temperature time series back to 1828. Up to 30% of the low-frequency variance can be accounted for with the 18.6-year nodal signal. Additionally, spectral analysis of these air temperature variations indicates a significant low-frequency peak in the range of the 18.6-year signal. Similar low-frequency signals have been reported for Hudson Bay air temperatures since 1700, for sea surface temperatures in the North Atlantic from 1876 to 1939, and for sea level in the high-latitude southern hemisphere. The water column temperature variations presented here are the first evidence that the upper ocean is responding to this very long period tidal forcing. An enhanced high-latitude response to the 18.6-year forcing is predicted by equilibrium tide theory, and it should be most evident at latitudes poleward of about 50[degree]. These low-frequency ocean-atmosphere variations must be considered in high-latitude assessments of global climate change, since they are of the same magnitude as many of the predicted global changes. 29 refs., 5 figs., 2 tabs.

  15. Weathering of plagioclase across variable flow and solute transport regimes

    NASA Astrophysics Data System (ADS)

    Pacheco, Fernando A. L.; Van der Weijden, Cornelis H.

    2012-02-01

    SummaryThe study area is situated in a fault zone with fractured granites and metasediments. In a conceptual model, infiltrating water first passes the bedrock cover of soil and saprolite and then partly enters the fractures. Weathering reactions of minerals occur in small pores and fissures in the bedrock cover zone to continue in the larger fractures. Pumping tests were carried out in a number of boreholes to measure the drawdown as a function of pumping time. From the results, values of transmissivity ( T) could be derived. In combination with the storage coefficient ( S) for similar fault zones, the hydraulic diffusivity ( D = T/ S) could be computed. Water samples, collected from the boreholes, represent fluid packets with a history of weathering reactions in the bedrock cover and in the larger fractures. The major element composition of these samples was used by means of the SiB mass balance algorithm ( Pacheco and Van der Weijden, 1996) to calculate the moles L -1 of dissolved plagioclase (oligoclase with An ≈ 0.20) and the moles L -1 of secondary phases (gibbsite, halloysite, smectite) precipitated along the flow paths of the samples. These results were then used to calculate the net dissolved silica concentrations ( [HSiO40]) related to dissolution of plagioclase followed by precipitation of each of the secondary phases. An interpretation of a plot of each of these [HSiO40] 's versusD is that at D < 0.7 m 2 s -1, dissolution of plagioclase is followed by precipitation of halloysite in the large fractures of the fault zone (open system), whereas at D ⩾ 0.7 m 2 s -1 precipitation of both halloysite and smectite occurs in the rock matrix with small fissures and pores (semi-open system). Before being pumped, the percolating fluids travelled 0.01-13.7 years. During these periods, plagioclase weathered at rates ( W Pl) of 10 -(12.9±1.1) moles m -2 s -1, which are approximately 2.2 orders of magnitude higher than solid-state weathering rates reported in

  16. Physical mechanisms of solar variability influence on weather and climate

    NASA Astrophysics Data System (ADS)

    Avakyan, Sergei

    2010-05-01

    Numerous researches into correlation of weather and climate characteristics with solar and geomagnetic activity confirm that such correlation does exist. However there is some uncertainty in interpretation of the Sun-weather-climate relations. The paper considers the main causes of this uncertainty which are as follows - the lack of permanent monitoring data on ionizing solar EUV/X-ray radiation including periods of flares; and also the data on electron fluxes of keV energy precipitating from radiation belts first of all during geomagnetic storms; - multiplicity of Sun-weather-climate links; - the lack of understanding what are the mechanisms of solar-geomagnetic activity (flares and storms) influence on weather and climate characteristics; By now mainly the research on galactic cosmic rays (GSR) including Forbush effects and solar cosmic rays (SCR) influences on atmosphere transparence characteristics and further on climate-weather characteristics have been carried out. The GCR flux increase causes the growth of low (usually optically thick) cloudness and therefore produces in generally cooling effect on the mean surface air temperature. The appearance of SCR causes the reduction of stratospheric and tropospheric transparence and produces also usually cooling effect However these events are rare and corresponding variations of fluxes energy are small. At the same time such strong and frequent manifestations of solar activity as flares and magnetic storms are not so far taken into account since it is not known what physical mechanisms could be responsible for energy transfer from solar flares and magnetic storms to the lower atmosphere. The paper describes a novel radio-optical mechanism responsible for the solar-terrestrial links which acts as a three-stage trigger and which could be useful for solving the problem "Sun- weather-climate". This physical mechanism is based on taking into account the excitation of Rydberg states of atoms and molecules in generation of

  17. Earth tides

    SciTech Connect

    Harrison, J.C.

    1984-01-01

    Nineteen papers on gravity, tilt, and strain tides are compiled into this volume. Detailed chapters cover the calculation of the tidal forces and of the Earth's response to them, as well as actual observations of earth tides. Partial Contents: On Earth tides. The tidal forces: Tidal Forces. New Computations of the Tide-Generating Potential. Corrected Tables of Tidal Harmonics. The Theory of Tidal Deformations. Body Tides on an Elliptical, Rotating, Elastic and Oceanless Earth, Deformation of the Earth by Surface Loads. Gravimetric Tidal Loading Computed from Integrated Green's Functions. Tidal Friction in the Solid Earth. Loading Tides Versus Body Tides. Lunar Tidal Acceleration from Earth Satellite Orbit Analysis. Observations: gravity. Tidal Gravity in Britain: Tidal Loading and the Spatial Distribution of the Marine Tide. Tidal Loading along a Profile Europe-East Africa-South Asia-Australia and the Pacific Ocean. Detailed Gravity-Tide Spectrum between One and Four Cycles per Day. Observations: tilt and strain. Cavity and Topographic Effects in Tilt and Strain Measurement. Observations of Local Elastic Effects on Earth Tide Tilts and Strains.

  18. King Tide floods in Tuvalu

    NASA Astrophysics Data System (ADS)

    Lin, C.-C.; Ho, C.-R.; Cheng, Y.-H.

    2013-05-01

    The spatial and temporal distributions of sea level rise present regional floods in some certain areas. The low-lying island countries are obviously the spots affected severely. Tuvalu, an atoll island country located in the south-west Pacific Ocean, is suffering the devastating effects of losing life, property, and intending migration caused by floods. They blame the regional flooding to King Tide, a term used but not clearly identified by Pacific islanders. In this study, we clarify what King Tide is first. By the tide gauge and topography data, we estimated the reasonable value of 3.2 m as the threshold of King Tide. This definition also fits to the statement by National Oceanic and Atmospheric Administration (NOAA) of King Tide occurring once or twice a year. In addition, We cross validate the 19 yr data of tide gauge and satellite altimeter (1993-2012), the correlation coefficient indicates King Tide phenomenon is considerable connected to warm water mass. The 28 King Tide events revealed the fact that flooding can be referenced against spring tide levels, so can it be turned up by warm water mass. The warm water mass pushes up sea level; once spring tide, storm surge, or other climate variability overlaps it, the rising sea level might overflow and so has been called "King Tide" for the floods in Tuvalu. This study provides more understanding of the signals of King Tide and an island country case study of regional sea level rise.

  19. Weather.

    ERIC Educational Resources Information Center

    Web Feet K-8, 2000

    2000-01-01

    This subject guide to weather resources includes Web sites, CD-ROMs and software, videos, books, audios, magazines, and professional resources. Related disciplines are indicated, age levels are specified, and a student activity is included. (LRW)

  20. On the role of wind and tide in generating variability of Pearl River plume during summer in a coupled wide estuary and shelf system

    NASA Astrophysics Data System (ADS)

    Zu, Tingting; Wang, Dongxiao; Gan, Jianping; Guan, Weibing

    2014-08-01

    A numerical simulation of the buoyant river plume over the Pearl River Estuary (PRE) and adjacent shelf during a typical upwelling favorable wind period of the summer monsoon is utilized to explore the responses of the plume to wind and tide forcing. The model is forced with time-dependent river discharge, wind and tide, and it shows reasonable ability to capture the basic structure and responses of the plume. Additional numerical experiments that are forced without either wind or tide are used to evaluate the relative importance of wind and tide in generating plume variability. Results show that the vertical structure of the plume and the strength of the stratification in the estuary are determined by the combination of the buoyancy forcing associated with river discharge and tidal forcing, and vary with the advection process, while the horizontal shape and spreading of the plume over the shelf are highly influenced by the wind-driven coastal current, and are more susceptible to the change of vertical mixing. Mechanical energy analysis in each dynamical region (upper, middle, lower estuary, and shelf) reveals that this is because the system mainly gains energy from tide (wind) in the estuary (shelf), and loses energy to the bottom friction (internal-shear mixing) in the estuary (shelf). The largest forcing and dissipation terms in the middle PRE, and at the entrances of smaller estuaries such as Huang Mao Hai, are due to tidal forcing, which enables the middle PRE to serve dynamically as the entrance of an estuary, where the transition of the river plume into coastal buoyancy current usually takes place. In addition, the mixing efficiency increases from upper PRE to the shelf and from strong to weak mixing period, thus the plume in the well-mixed upper estuary is not as sensitive to the changes of wind and tide as that over the highly stratified shelf.

  1. A Bayesian hierarchical model with spatial variable selection: the effect of weather on insurance claims

    PubMed Central

    Scheel, Ida; Ferkingstad, Egil; Frigessi, Arnoldo; Haug, Ola; Hinnerichsen, Mikkel; Meze-Hausken, Elisabeth

    2013-01-01

    Climate change will affect the insurance industry. We develop a Bayesian hierarchical statistical approach to explain and predict insurance losses due to weather events at a local geographic scale. The number of weather-related insurance claims is modelled by combining generalized linear models with spatially smoothed variable selection. Using Gibbs sampling and reversible jump Markov chain Monte Carlo methods, this model is fitted on daily weather and insurance data from each of the 319 municipalities which constitute southern and central Norway for the period 1997–2006. Precise out-of-sample predictions validate the model. Our results show interesting regional patterns in the effect of different weather covariates. In addition to being useful for insurance pricing, our model can be used for short-term predictions based on weather forecasts and for long-term predictions based on downscaled climate models. PMID:23396890

  2. Daily weather variables and affective disorder admissions to psychiatric hospitals.

    PubMed

    McWilliams, Stephen; Kinsella, Anthony; O'Callaghan, Eadbhard

    2014-12-01

    Numerous studies have reported that admission rates in patients with affective disorders are subject to seasonal variation. Notwithstanding, there has been limited evaluation of the degree to which changeable daily meteorological patterns influence affective disorder admission rates. A handful of small studies have alluded to a potential link between psychiatric admission rates and meteorological variables such as environmental temperature (heat waves in particular), wind direction and sunshine. We used the Kruskal-Wallis test, ARIMA and time-series regression analyses to examine whether daily meteorological variables--namely wind speed and direction, barometric pressure, rainfall, hours of sunshine, sunlight radiation and temperature--influence admission rates for mania and depression across 12 regions in Ireland over a 31-year period. Although we found some very weak but interesting trends for barometric pressure in relation to mania admissions, daily meteorological patterns did not appear to affect hospital admissions overall for mania or depression. Our results do not support the small number of papers to date that suggest a link between daily meteorological variables and affective disorder admissions. Further study is needed. PMID:24599495

  3. An Extended Version of the Richardson Model for Simulating Daily Weather Variables.

    NASA Astrophysics Data System (ADS)

    Parlange, Marc B.; Katz, Richard W.

    2000-05-01

    The Richardson model is a popular technique for stochastic simulation of daily weather variables, including precipitation amount, maximum and minimum temperature, and solar radiation. This model is extended to include two additional variables, daily mean wind speed and dewpoint, because these variables (or related quantities such as relative humidity) are required as inputs for certain ecological/vegetation response and agricultural management models. To allow for the positively skewed distribution of wind speed, a power transformation is applied. Solar radiation also is transformed to make the shape of its modeled distribution more realistic. A model identification criterion is used as an aid in determining whether the distributions of these two variables depend on precipitation occurrence. The approach can be viewed as an integration of what is known about the statistical properties of individual weather variables into a single multivariate model.As an application, this extended model is fitted to weather data in the Pacific Northwest. To aid in understanding how such a stochastic weather generator works, considerable attention is devoted to its statistical properties. In particular, marginal and conditional distributions of wind speed and solar radiation are examined, with the model being capable of representing relationships between variables in which the variance is not constant, as well as certain forms of nonlinearity.

  4. Effect of variability in weather conditions on conductor temperature and the dynamic rating of transmission lines

    SciTech Connect

    Foss, S.D.; Lin, S.H. ); Maraio, R.A.; Schrayshuen, H. )

    1988-10-01

    Simultaneous weather and conductor data were collected from these locations situated in New York State and Western Massachusetts. The two New York State locations represent the termination points of a 230 kV seventy-mile overhead line. The transmission line consists of a Drake 795 kcmil ACSR conductor. Data were monitored using on-line sensor equipment developed by the Research and Development Department of the Niagara Mohawk Power Corporation. The purposes of the investigation were to analyze variability in weather conditions, conductor temperature and calculated dynamic ratings that exist along transmission lines. Reported here are variabilities in air temperature, wind speed, conductor current, conductor surface temperature and calculated dynamic ratings.

  5. Daily weather variables and affective disorder admissions to psychiatric hospitals

    NASA Astrophysics Data System (ADS)

    McWilliams, Stephen; Kinsella, Anthony; O'Callaghan, Eadbhard

    2014-12-01

    Numerous studies have reported that admission rates in patients with affective disorders are subject to seasonal variation. Notwithstanding, there has been limited evaluation of the degree to which changeable daily meteorological patterns influence affective disorder admission rates. A handful of small studies have alluded to a potential link between psychiatric admission rates and meteorological variables such as environmental temperature (heat waves in particular), wind direction and sunshine. We used the Kruskal-Wallis test, ARIMA and time-series regression analyses to examine whether daily meteorological variables—namely wind speed and direction, barometric pressure, rainfall, hours of sunshine, sunlight radiation and temperature—influence admission rates for mania and depression across 12 regions in Ireland over a 31-year period. Although we found some very weak but interesting trends for barometric pressure in relation to mania admissions, daily meteorological patterns did not appear to affect hospital admissions overall for mania or depression. Our results do not support the small number of papers to date that suggest a link between daily meteorological variables and affective disorder admissions. Further study is needed.

  6. Decadal climatic variability and regional weather simulation: stochastic nature of forest fuel moisture and climatic forcing

    NASA Astrophysics Data System (ADS)

    Tsinko, Y.; Johnson, E. A.; Martin, Y. E.

    2014-12-01

    Natural range of variability of forest fire frequency is of great interest due to the current changing climate and seeming increase in the number of fires. The variability of the annual area burned in Canada has not been stable in the 20th century. Recently, these changes have been linked to large scale climate cycles, such as Pacific Decadal Oscillation (PDO) phases and El Nino Southern Oscillation (ENSO). The positive phase of the PDO was associated with the increased probability of hot dry spells leading to drier fuels and increased area burned. However, so far only one historical timeline was used to assess correlations between the natural climate oscillations and forest fire frequency. To counteract similar problems, weather generators are extensively used in hydrological and agricultural modeling to extend short instrumental record and to synthesize long sequences of daily weather parameters that are different from but statistically similar to historical weather. In the current study synthetic weather models were used to assess effects of alternative weather timelines on fuel moisture in Canada by using Canadian Forest Fire Weather Index moisture codes and potential fire frequency. The variability of fuel moisture codes was found to increase with the increased length of simulated series, thus indicating that the natural range of variability of forest fire frequency may be larger than that calculated from available short records. It may be viewed as a manifestation of a Hurst effect. Since PDO phases are thought to be caused by diverse mechanisms including overturning oceanic circulation, some of the lower frequency signals may be attributed to the long term memory of the oceanic system. Thus, care must be taken when assessing natural variability of climate dependent processes without accounting for potential long-term mechanisms.

  7. Influence of environmental and prey variables on low tide shorebird habitat use within the Robbins Passage wetlands, Northwest Tasmania

    NASA Astrophysics Data System (ADS)

    Spruzen, Fiona L.; Richardson, Alastair M. M.; Woehler, Eric J.

    2008-06-01

    Shorebirds feed primarily on tidal flats, and their distribution over these flats is influenced by their prey and abiotic factors. These factors act by influencing the distribution and abundance of the prey, or the shorebirds ability to exploit it. The aims of this study were to investigate the low tide foraging distribution of shorebirds at four sites within the Robbins Passage wetlands, and the environmental and invertebrate factors that may influence their distribution. The greatest densities and number of shorebirds were found at Shipwreck Point and East Inlet. The shorebirds within-site distribution was also non-random, with the shorebirds present in greatest densities at the water's edge and low intertidal stratum, although this varied among species. Generally, on a small spatial scale, invertebrate diversity was positively correlated, and seagrass leaf mass was negatively correlated, with shorebird feeding density. On a large spatial scale, invertebrate biomass and seagrass root mass were positively correlated with shorebird feeding density. Invertebrate biomass and seagrass root mass explained 71% of the variance in total shorebird feeding density on the tidal flats. The variation in shorebird feeding density and diversity was therefore partly explained by invertebrate diversity and biomass, as well as the environmental factors seagrass roots and leaf mass and tidal flat area, although the strength of these relationships was influenced by the two different spatial scales of the study. The strength of the relationships between shorebird feeding density and the invertebrate and environmental variables was stronger on a large spatial scale. The presence of seagrass may have influenced shorebird-feeding density by affecting the invertebrate abundance and composition or the shorebirds ability to detect and capture their prey. The area of the tidal flat had opposing effects on the shorebird species. These results can be used to assist in the development of

  8. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    NASA Technical Reports Server (NTRS)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  9. Weather data, site variability, and probabilities of success: a practical perspective on adaptive management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arid and semi-arid rangelands occupy over half of the earth’s surface and are characterized by high variability in seasonal and annual precipitation. Invasive plants compete for soil and water and exacerbate inherent weather limitations for desirable plant establishment. Management guidelines for ...

  10. Weather variability, ecological processes and optimization of soil micro-environment for rangeland restoration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arid and semi-arid rangelands occupy over half of the earth’s surface and are characterized by relatively high variability in seasonal and annual patterns of precipitation. Invasive plants compete for soil and water resources and exacerbate inherent weather limitations for native plant establishmen...

  11. The Spatial Variability of Weathering Processes in a Peruvian River System

    NASA Astrophysics Data System (ADS)

    Torres, M. A.; Ballew, N.; Clark, K.; West, A.

    2011-12-01

    The role of floodplains in the weathering of sediment exported from mountainous regions is poorly understood and has the potential to play a significant role in the overall weathering budget of large river systems. While high rates of floodplain weathering have been measured in the Himalayan system [1], there are conflicting results concerning the importance of floodplain weathering in the Amazon system [2-3]. To address this issue, the dissolved major element chemistry of the Kosñipata-Madre de Dios river system in Peru was measured monthly in nested catchments spanning the headwater-floodplain transition in order to determine spatially-resolved weathering rates and to examine any associated changes in weathering processes. Analysis of the dissolved major element data reveals a change in the dominant weathering process controlling the Ca2+ and Mg2+ fluxes associated with the headwater-floodplain transition. Based on (Ca2+ + Mg2+) / HCO3- ratios near 0.5, Ca2+ and Mg2+ fluxes in the floodplain are controlled by carbonate dissolution by carbonic acid. In the Andean catchments, variable (Ca2+ + Mg2+) / HCO3- ratios, (Ca2+ + Mg2+) / SO42- ratios near 1, and high SO42- concentrations suggest that either carbonate dissolution by sulfuric acid or sulfate mineral dissolution is the main control on Ca2+ and Mg2+ fluxes. This observed change is significant as it has important implications for the net consumption of CO2 by silicate weathering in this river system. [1] West, AJ et al, 2002, Geology 30: 355-358, [2] Gaillardet, J et al, 2006, Geochim. Cosmochim. Acta 70: 189, [3] Moquet, J et al, 2011, Chem. Geol 287: 1-26

  12. Variability of the internal tide on the southern Monterey Bay continental shelf and associated bottom boundary layer sediment transport

    NASA Astrophysics Data System (ADS)

    Rosenberger, K. J.; Storlazzi, C. D.; Cheriton, O. M.; McPhee-Shaw, E. E.

    2014-12-01

    A 6-month deployment of instrumentation from April to October 2012 in 90 m water depth near the outer edge of the mid-shelf mud belt in southern Monterey Bay, California, reveals the relative importance of internal tides on the resuspension and transport of seabed sediment. Observations consisted of time-series measurements of water-column currents, temperature and salinity, and near-bed currents and suspended matter. The internal tide accounted for 15-25% of the water-column current variance and the barotropic tide accounted for up to 35%. The subtidal flow showed remarkably little shear and was dominated by the 7-14 day band, which is associated with relaxations in the dominant equatorward winds typical of coastal California in the spring and summer. Upwelling and relaxation events resulted in strong near-bed flows and accounted for almost half of the current stress on the seafloor (not accounting for wave orbital velocities), and may have driven along-shelf geostrophic flow during steady state conditions. Several elevated suspended particulate matter (SPM) events occurred within 3 m of the bed and were generally associated with higher, long-period surface waves. However, these peaks in SPM did not coincide with the predicted resuspension events from the modeled combined wave-current shear stress, indicating that the observed SPM at our site was most likely resuspended elsewhere and advected along-isobath. Sediment flux is almost equal in magnitude in the alongshore and cross-shore directions. Instances of wave-current shear stress that exceeded the threshold of resuspension for the silty-clays common at these water depths only occurred when near-bed orbital velocities due to long-period surface waves coincided with vigorous near-bed currents associated with the internal tide or upwelling/relaxation events. Thus, the internal tide and upwelling/relaxation dynamics are important in the transport of sediment during the relatively quiescent summer months.

  13. Weather patterns as a downscaling tool - evaluating their skill in stratifying local climate variables

    NASA Astrophysics Data System (ADS)

    Murawski, Aline; Bürger, Gerd; Vorogushyn, Sergiy; Merz, Bruno

    2016-04-01

    The use of a weather pattern based approach for downscaling of coarse, gridded atmospheric data, as usually obtained from the output of general circulation models (GCM), allows for investigating the impact of anthropogenic greenhouse gas emissions on fluxes and state variables of the hydrological cycle such as e.g. on runoff in large river catchments. Here we aim at attributing changes in high flows in the Rhine catchment to anthropogenic climate change. Therefore we run an objective classification scheme (simulated annealing and diversified randomisation - SANDRA, available from the cost733 classification software) on ERA20C reanalyses data and apply the established classification to GCMs from the CMIP5 project. After deriving weather pattern time series from GCM runs using forcing from all greenhouse gases (All-Hist) and using natural greenhouse gas forcing only (Nat-Hist), a weather generator will be employed to obtain climate data time series for the hydrological model. The parameters of the weather pattern classification (i.e. spatial extent, number of patterns, classification variables) need to be selected in a way that allows for good stratification of the meteorological variables that are of interest for the hydrological modelling. We evaluate the skill of the classification in stratifying meteorological data using a multi-variable approach. This allows for estimating the stratification skill for all meteorological variables together, not separately as usually done in existing similar work. The advantage of the multi-variable approach is to properly account for situations where e.g. two patterns are associated with similar mean daily temperature, but one pattern is dry while the other one is related to considerable amounts of precipitation. Thus, the separation of these two patterns would not be justified when considering temperature only, but is perfectly reasonable when accounting for precipitation as well. Besides that, the weather patterns derived from

  14. Variable Quaternary chemical weathering fluxes and imbalances in marine geochemical budgets.

    PubMed

    Vance, Derek; Teagle, Damon A H; Foster, Gavin L

    2009-03-26

    Rivers are the dominant source of many elements and isotopes to the ocean. But this input from the continents is not balanced by the loss of the elements and isotopes through hydrothermal and sedimentary exchange with the oceanic crust, or by temporal changes in the marine inventory for elements that are demonstrably not in steady state. To resolve the problem of the observed imbalance in marine geochemical budgets, attention has been focused on uncertainties in the hydrothermal and sedimentary fluxes. In recent Earth history, temporally dynamic chemical weathering fluxes from the continents are an inevitable consequence of periodic glaciations. Chemical weathering rates on modern Earth are likely to remain far from equilibrium owing to the physical production of finely ground material at glacial terminations that acts as a fertile substrate for chemical weathering. Here we explore the implications of temporal changes in the riverine chemical weathering flux for oceanic geochemical budgets. We contend that the riverine flux obtained from observations of modern rivers is broadly accurate, but not representative of timescales appropriate for elements with oceanic residence longer than Quaternary glacial-interglacial cycles. We suggest that the pulse of rapid chemical weathering initiated at the last deglaciation has not yet decayed away and that weathering rates remain about two to three times the average for an entire late Quaternary glacial cycle. Taking into account the effect of the suggested non-steady-state process on the silicate weathering flux helps to reconcile the modelled marine strontium isotope budget with available data. Overall, we conclude that consideration of the temporal variability in riverine fluxes largely ameliorates long-standing problems with chemical and isotopic mass balances in the ocean. PMID:19325631

  15. Quantifying the weather-signal in national crop-yield variability

    NASA Astrophysics Data System (ADS)

    Frieler, K.; Arneth, A.; Balkovic, J.; Chryssanthacopoulos, J.; Deryng, D.; Elliott, J. W.; Folberth, C.; Khabarov, N.; Mueller, C.; Olin, S.; Pugh, T.; Schaphoff, S.; Schewe, J.; Schmid, E.; Schauberger, B.; Warszawski, L.; Levermann, A.

    2015-12-01

    Year-to-year variations in crop yields can have major impacts on the livelihoods of subsistence farmers and may trigger significant global price fluctuations with particularly severe consequences for people in developing countries. The fluctuations can be induced by weather conditions but also by management decisions, diseases, and pests. To get a better understanding of future sensitivities to climate change it is important to quantify the degree to which historical crop yields are determined by weather fluctuations. This separation from other influences is usually done by highly simplified empirical models. In contrast, here we provide a conservative estimate of the fraction of the observed national yield variability that is caused by weather, using state-of-the-art process-based crop model simulations. As these models provide a detailed representation of our current understanding of the underlying processes they are also suitable to assess potential adaptation options. We provide an identification of the countries where the weather induced variability of crop yields is particularly high (explained variance > 50%). In addition, inhibiting water stress by simulating yields assuming full irrigation shows that water limitation is the main driver of the observed variations in most of these countries.

  16. The impact of the spatial variability in bottom roughness on tidal dynamics and energetics, a case study: the M 2 surface tide in the North European Basin

    NASA Astrophysics Data System (ADS)

    Kagan, Boris A.; Sofina, Ekaterina V.; Rashidi, Ebrahim

    2012-12-01

    A modified version of the 3D finite-element hydrostatic model QUODDY-4 is used to quantify the changes in the dynamics and energetics of the M 2 surface tide in the North European Basin, induced by the spatial variability in bottom roughness. This version differs from the original one, as it introduces a module providing evaluation of the drag coefficient in the bottom boundary layer (BBL) and by accounting for the equilibrium tide. The drag coefficient is found from the resistance laws for an oscillatory rotating turbulent BBL over hydrodynamically rough and incompletely rough underlying surfaces, describing how the wave friction factor as well as other resistance characteristics depend on the dimensionless similarity parameters for the BBL. It is shown that the influence of the spatial variability in bottom roughness is responsible for some specific changes in the tidal amplitudes, phases, and the maximum tidal velocities. These changes are within the model noise, while the changes in the averaged (over a tidal cycle) horizontal wave transport and the averaged dissipation of barotropic tidal energy may be of the same orders of magnitude as are the above energetic characteristics as such. Thus, contrary to present views, ignoring the spatial variability in bottom roughness at least in the North European Basin is only partially correct: it is valid for the tidal dynamics, but is liable to break down for the tidal energetics.

  17. Kingdom of the Tides.

    ERIC Educational Resources Information Center

    Carter, Samuel, III

    Areas of discussion are the history of tides, the forces which exert an influence upon the earth's tides, the behavior of tides as modified by terrestrial features, "freak" behavior of tides, the marine life which inhabits tidal areas, the manner in which tides have helped to shape the course of history, how tides affect our lives on a day to day…

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

    NASA Technical Reports Server (NTRS)

    Roberts, J. Brent; Clayson, Carol Anne

    2013-01-01

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

  19. WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT

    SciTech Connect

    CAMERON, M.A.

    2007-04-16

    Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. All calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures.

  20. WEATHER RELATED VARIABILITY OF CALORIMETERY PERFORMANCE IN A POORLY CONTROLLED ENVIRONMENT

    SciTech Connect

    CAMERON, M.A.

    2007-04-16

    Four Antech airbath calorimeters at the Hanford site were studied for three summers and two winters in a location not well-shielded from outside temperature changes. Calorimeters showed significant increases in variability of standard measurements during hot weather. The increased variability is postulated to be due to a low setting of the Peltier cold face temperature, which doesn't allow the instrument to drain heat fast enough in a hot environment. A higher setting of the Peltier cold face might lead to better performance in environments subjected to a broad range of temperatures.

  1. Low frequency variability of European weather patterns and its impact on power generation in northern Europe

    NASA Astrophysics Data System (ADS)

    Masato, Giacomo; Slavov, Georgi

    2016-04-01

    It is well known that Europe is becoming increasingly reliant on the power generation from the solar and wind sources. Germany is a leader in such a trend - it is then interesting to study to what extent the low-frequency variability of the European weather patterns impacts the power production in this country. Rather than identifying such patterns starting from the weather angle, four weather regimes are identified that maximize and minimize the production of solar and wind power. The analysis of their past occurrence and trends allows us to estimate the potential amount of energy produced for any given year (assuming a constant installed capacity). It is found that the sole change in such weather regimes over the recent years is able to drive up to a 20% annual difference in power generation. This also throws an interesting challenge at the scientific community, whereby the future projection of these regimes can heavily influence both the short- and long-term Eurozone plans in terms of European renewable energy targets.

  2. Interpreting and analyzing King Tide in Tuvalu

    NASA Astrophysics Data System (ADS)

    Lin, C.-C.; Ho, C.-R.; Cheng, Y.-H.

    2014-02-01

    The spatial and temporal distribution of sea-level rise has the potential to cause regional flooding in certain areas, and low-lying island countries are severely at risk. Tuvalu, an atoll country located in the southwest Pacific Ocean, has been inundated by this regional flooding for decades. Tuvaluans call this regional flooding phenomenon King Tide, a term not clearly defined, blaming it for loss of life and property in announcing their intention to migrate. In this study, we clarified and interpreted King Tide, and analyzed the factors of King Tide in Tuvalu. Using tide gauge and topographical data, we estimated that 3.2 m could be considered the threshold of King Tide, which implied half of the island of Tuvalu was flooded with seawater. This threshold is consistent with the finding of the National Oceanic and Atmospheric Administration that King Tide events occur once or twice a year. We surveyed 28 King Tide events to analyze the factors of regional flooding. Tide gauge and satellite altimeter data from 1993 to 2012 were cross-validated and indicated that the King Tide phenomenon is significantly related to the warm-water effect. Warm water contributed to the King Tide phenomenon by an average of 5.1% and a maximum of 7.8%. The height of King Tide is affected by the combined factors of spring tide, storm surge, climate variability, and, significantly, by the warm-water effect.

  3. Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina

    PubMed Central

    Estallo, Elizabet L.; Ludueña-Almeida, Francisco F.; Introini, María V.; Zaidenberg, Mario; Almirón, Walter R.

    2015-01-01

    This study aims to develop a forecasting model by assessing the weather variability associated with seasonal fluctuation of Aedes aegypti oviposition dynamic at a city level in Orán, in northwestern Argentina. Oviposition dynamics were assessed by weekly monitoring of 90 ovitraps in the urban area during 2005-2007. Correlations were performed between the number of eggs collected weekly and weather variables (rainfall, photoperiod, vapor pressure of water, temperature, and relative humidity) with and without time lags (1 to 6 weeks). A stepwise multiple linear regression analysis was performed with the set of meteorological variables from the first year of study with the variables in the time lags that best correlated with the oviposition. Model validation was conducted using the data from the second year of study (October 2006- 2007). Minimum temperature and rainfall were the most important variables. No eggs were found at temperatures below 10°C. The most significant time lags were 3 weeks for minimum temperature and rains, 3 weeks for water vapor pressure, and 6 weeks for maximum temperature. Aedes aegypti could be expected in Orán three weeks after rains with adequate min temperatures. The best-fit forecasting model for the combined meteorological variables explained 70 % of the variance (adj. R2). The correlation between Ae. aegypti oviposition observed and estimated by the forecasting model resulted in rs = 0.80 (P < 0.05). The forecasting model developed would allow prediction of increases and decreases in the Ae. aegypti oviposition activity based on meteorological data for Orán city and, according to the meteorological variables, vector activity can be predicted three or four weeks in advance. PMID:25993415

  4. Weather Variability Associated with Aedes (Stegomyia) aegypti (Dengue Vector) Oviposition Dynamics in Northwestern Argentina.

    PubMed

    Estallo, Elizabet L; Ludueña-Almeida, Francisco F; Introini, María V; Zaidenberg, Mario; Almirón, Walter R

    2015-01-01

    This study aims to develop a forecasting model by assessing the weather variability associated with seasonal fluctuation of Aedes aegypti oviposition dynamic at a city level in Orán, in northwestern Argentina. Oviposition dynamics were assessed by weekly monitoring of 90 ovitraps in the urban area during 2005-2007. Correlations were performed between the number of eggs collected weekly and weather variables (rainfall, photoperiod, vapor pressure of water, temperature, and relative humidity) with and without time lags (1 to 6 weeks). A stepwise multiple linear regression analysis was performed with the set of meteorological variables from the first year of study with the variables in the time lags that best correlated with the oviposition. Model validation was conducted using the data from the second year of study (October 2006- 2007). Minimum temperature and rainfall were the most important variables. No eggs were found at temperatures below 10 °C. The most significant time lags were 3 weeks for minimum temperature and rains, 3 weeks for water vapor pressure, and 6 weeks for maximum temperature. Aedes aegypti could be expected in Orán three weeks after rains with adequate min temperatures. The best-fit forecasting model for the combined meteorological variables explained 70 % of the variance (adj. R(2)). The correlation between Ae. aegypti oviposition observed and estimated by the forecasting model resulted in rs = 0.80 (P < 0.05). The forecasting model developed would allow prediction of increases and decreases in the Ae. aegypti oviposition activity based on meteorological data for Orán city and, according to the meteorological variables, vector activity can be predicted three or four weeks in advance. PMID:25993415

  5. Temporal and Spatial Variability in ENSO Teleconnections to Daily Weather Donditions in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    McAfee, S. A.; Wise, E. K.; Csank, A. Z.

    2014-12-01

    Classic teleconnection analysis has focused on relationships between modes of variability and seasonal average conditions. Growing needs for seasonally specific planning, as well as an expanding body of research showing instability in teleconnections, suggest that there is a need to evaluate teleconnections over narrower seasonal windows and to investigate variables other than average temperature, snowpack, and total precipitation. Here, ENSO teleconnections to snow-fraction, wet-day frequency and temperature, and air-mass type (using Sheridan's synoptic classification), as well as to average temperature and precipitation, were evaluated at weather stations across the Pacific Northwest. The analysis was performed separately for early (October/November), middle (December/January) and late (February/March) portions of the cool-season. The stability of these relationships over time was also evaluated. Currently, ENSO has the strongest and most widespread influence on PNW weather late in the cool season, with some effect in the autumn, but little detectable impact in the mid-winter. Earlier in the 20th century, the autumn peak in ENSO influence was somewhat more pronounced and the spring somewhat less. There were also modest geographic differences in teleconnection patterns, such as a region-wide response in average February-March temperature, but more localized effects on wet-day temperature. Geographic and seasonal distinctions in teleconnections to weather and climate could drive important differences in ecological and hydrological outcomes. This type of daily-level analysis may be useful in meeting the needs of stakeholders interested in using teleconnections for seasonal planning, but who may need more seasonally specific information or non-standard variables. However, this study also demonstrates the need for a thorough understanding of teleconnection spatial patterns, seasonal variability, and temporal flexibility when they are being presented to stakeholders as

  6. Predicting the start week of respiratory syncytial virus outbreaks using real time weather variables

    PubMed Central

    2010-01-01

    Background Respiratory Syncytial Virus (RSV), a major cause of bronchiolitis, has a large impact on the census of pediatric hospitals during outbreak seasons. Reliable prediction of the week these outbreaks will start, based on readily available data, could help pediatric hospitals better prepare for large outbreaks. Methods Naïve Bayes (NB) classifier models were constructed using weather data from 1985-2008 considering only variables that are available in real time and that could be used to forecast the week in which an RSV outbreak will occur in Salt Lake County, Utah. Outbreak start dates were determined by a panel of experts using 32,509 records with ICD-9 coded RSV and bronchiolitis diagnoses from Intermountain Healthcare hospitals and clinics for the RSV seasons from 1985 to 2008. Results NB models predicted RSV outbreaks up to 3 weeks in advance with an estimated sensitivity of up to 67% and estimated specificities as high as 94% to 100%. Temperature and wind speed were the best overall predictors, but other weather variables also showed relevance depending on how far in advance the predictions were made. The weather conditions predictive of an RSV outbreak in our study were similar to those that lead to temperature inversions in the Salt Lake Valley. Conclusions We demonstrate that Naïve Bayes (NB) classifier models based on weather data available in real time have the potential to be used as effective predictive models. These models may be able to predict the week that an RSV outbreak will occur with clinical relevance. Their clinical usefulness will be field tested during the next five years. PMID:21044325

  7. Tide-related variability of TAG hydrothermal activity observed by deep-sea monitoring system and OBSH

    NASA Astrophysics Data System (ADS)

    Fujioka, Kantaro; Kobayashi, Kazuo; Kato, Kazuhiro; Aoki, Misumi; Mitsuzawa, Kyohiko; Kinoshita, Masataka; Nishizawa, Azusa

    1997-12-01

    Hydrothermal activities were monitored by an ocean bottom seismometer with hydrophone (OBSH) and a composite measuring system (Manatee) including CTD, current meter, transmission meter and cameras at a small depression on the TAG hydrothermal mound in the Mid-Atlantic Ridge. Low-frequency pressure pulses detected by the hydrophone with semi-diurnal periodicity seem to correspond to cycles of hydrothermal upflow from a small and short-lived smoker vent close to the observing site. The peaks of pressure pulses are synchronous with the maximum gradient of areal strain decrease due to tidal load release. Microearthquakes with very near epicenters occur sporadically and do not appear to be directly correlatable to hydrothermal venting. Temporal variations in bottom water temperature also have semi-diurnal periodicity but are more complicated than the pressure events. Temperatures may be affected both by upwelling of hot water and by lateral flow of the bottom current changing its directions with ocean tide.

  8. Tide and skew surge independence: New insights for flood risk

    NASA Astrophysics Data System (ADS)

    Williams, Joanne; Horsburgh, Kevin J.; Williams, Jane A.; Proctor, Robert N. F.

    2016-06-01

    Storm surges are a significant hazard to coastal communities around the world, putting lives at risk and costing billions of dollars in damage. Understanding how storm surges and high tides interact is crucial for estimating extreme water levels so that we can protect coastal communities. We demonstrate that in a tidal regime the best measure of a storm surge is the skew surge, the difference between the observed and predicted high water within a tidal cycle. Based on tide gauge records spanning decades from the UK, U.S., Netherlands, and Ireland we show that the magnitude of high water exerts no influence on the size of the most extreme skew surges. This is the first systematic proof that any storm surge can occur on any tide, which is essential for understanding worst-case scenarios. The lack of surge generation dependency on water depth emphasizes the dominant natural variability of weather systems in an observation-based analysis. Weak seasonal relationships between skew surges and high waters were identified at a minority of locations where long-period changes to the tidal cycle interact with the storm season. Our results allow advances to be made in methods for estimating the joint probabilities of storm surges and tides.

  9. Weather on Other Worlds: A Survey of Cloud-Induced Variability in Brown Dwarfs

    NASA Astrophysics Data System (ADS)

    Metchev, Stanimir; Radigan, Jacqueline; Apai, Daniel; Burgasser, Adam; Artigau, Etienne; Marley, Mark; Plavchan, Peter; Goldman, Bertrand; Geissler, Kerstin; Jayawardhana, Ray

    2011-05-01

    We propose a comprehensive program to detect periodic brightness variations in L and T dwarfs caused by the spatially inhomogeneous distribution of dusty clouds--weather patterns--in their atmospheres. We will seek trends over a broad set of substellar characteristics, encompassing objects with a range of temperatures, colors, and ages. While numerous variability searches have been conducted on L and T dwarfs to date, the vast majority have been ground-based and limited in precision. Only recently did members of the presently assembled team produce clear and repeatable detections of periodic flux variations in a half dozen substellar objects, thus providing the first strong evidence for heterogeneous cloud cover in their atmospheres. Spitzer's factor of 3-5 superior photometric precision enables a much more sensitive and comprehensive study of the atmospheric dynamics underlying the phenomenon. Our program will increase the scope of mid-infrared variability studies of brown dwarfs by more than an order of magnitude. We will target 44 ultra-cool dwarfs with spectral types between L3-T8, spanning the full color range at each spectral subtype, and including both low-gravity and field objects. We anticipate significant detections of periodicities as small as 10 milli-magnitudes in amplitude, which will enable the routine detection of weather patterns smaller than Jupiter's Great Red Spot on extrasolar substellar objects. The presence and brightness temperature distribution of these weather patterns will be analyzed in the context of state-of-the-art cloudy atmospheric models, and will reveal the longitudinal and vertical thermodynamics of substellar atmospheres. The proposed program will be relevant to the broader understanding of rotating, low-temperature, brown dwarf and exoplanetary atmospheres: a regime entirely different from that of the irradiated hot-Jupiter type extrasolar planets studied with Spitzer to date.

  10. Adaptability of free-floating green tide algae in the Yellow Sea to variable temperature and light intensity.

    PubMed

    Cui, Jianjun; Zhang, Jianheng; Huo, Yuanzi; Zhou, Lingjie; Wu, Qing; Chen, Liping; Yu, Kefeng; He, Peimin

    2015-12-30

    In this study, the influence of temperature and light intensity on the growth of seedlings and adults of four species of green tide algae (Ulvaprolifera, Ulvacompressa, Ulva flexuosa and Ulvalinza) from the Yellow Sea was evaluated. The results indicated that the specific growth rate (SGR) of seedlings was much higher than that of adults for the four species. The adaptability of U. prolifera is much wider: Adult daily SGRs were the highest among the four species at 15-20 °C with 10-600 μmol · m(-2) · s(-1) and 25-30 °C with 200-600 μmol · m(-2) · s(-1). SGRs were 1.5-3.5 times greater than the other three species at 15-25 °C with 200-600 μmol · m(-2) · s(-1). These results indicate that U. prolifera has better tolerance to high temperature and light intensity than the other three species, which may in part explain why only U. prolifera undergoes large-scale outbreaks and floats to the Qingdao coast while the other three species decline and disappear at the early stage of blooming. PMID:26573134

  11. Influence of synoptic weather patterns on solar irradiance variability in Europe

    NASA Astrophysics Data System (ADS)

    Parding, Kajsa; Hinkelman, Laura; Liepert, Beate; Ackerman, Thomas; Dagestad, Knut-Frode; Asle Olseth, Jan

    2014-05-01

    Solar radiation is important for many aspects of existence on Earth, including the biosphere, the hydrological cycle, and creatures living on the planet. Previous studies have reported decadal trends in observational records of surface shortwave (SW) irradiance around the world, too strong to be caused by varying solar output. These observed decadal trends have been dubbed "solar dimming and brightening" and are believed to be related to changes in atmospheric aerosols and cloud cover. Because the observed solar variability coincides with qualitative air pollution histories, the dimming and brightening have become almost synonymous with shortwave attenuation by anthropogenic aerosols. However, there are indications that atmospheric circulation patterns have influenced the dimming and brightening in some regions, e.g., Alaska and Scandinavia. In this work, we focus on the role of atmospheric circulation patterns in modifying shortwave irradiance. An examination of European SW irradiance data from the Global Energy Balance Archive (GEBA) shows that while there are periods of predominantly decreasing (~1970-1985) and increasing (~1985-2007) SW irradiance, the changes are not spatially uniform within Europe and in a majority of locations not statistically significant. To establish a connection between weather patterns and sunshine, regression models of SW irradiance are fitted using a daily classification of European weather called Grosswetterlagen (GWL). The GWL reconstructions of shortwave irradiance represent the part of the solar variability that is related to large scale weather patterns, which should be effectively separated from the influence of varying anthropogenic aerosol emissions. The correlation (R) between observed and reconstruced SW irradiance is between 0.31 and 0.75, depending on station and season, all statistically significant (p<0.05, estimated with a bootstrap test). In central and eastern parts of Europe, the observed decadal SW variability is

  12. The effect of weather variability on hydrology and erosion in the Pamir Mountains

    NASA Astrophysics Data System (ADS)

    Pohl, Eric; Gloaguen, Richard; Andermann, Christoff; Fuchs, Margret

    2015-04-01

    The Pamir Mountains (Pamirs) provide a unique climatological and geomorphological setting to investigate processes of mountain shaping. The two main atmospheric circulation systems in this region, the Westerlies in the western part, and the Indian summer monsoon in the south-eastern part, provide variable amounts of moisture. Strong inter-annual variations in moisture supply in other key-meteorological parameters suggest a very variable climate. Deflection of winds at the orogene margins and advective precipitation results in a strong precipitation gradient with moist margins and an arid central and eastern part. This gradient is generally accompanied by higher glaciation and more incised valleys at the margins and weak glaciation and preserved plateaus in the central and eastern parts. These differences seem to indicate a strong influence of precipitation and glaciation on erosion and mountain shaping, especially in the north-western part. However, recent studies utilizing cosmogenic nuclide (CN) techniques to derive basin-wide erosion rates revealed only weak correlations of modern climate with basin-wide erosion rates (integrated over ~1000 years). Independent analyses of historical suspended sediment yield (SSY) data for several rivers in the Pamirs show a similar distribution of high and low erosion rates compared to the CN method. However, CN-based erosion shows factor 3 to 30 higher erosion rates than SSY. We address this discrepancy by adopting a distributed hydrological model that we feed with state-of-the-art regional climate model, and remote sensing data. The model provides us with daily high spatial-resolution data of individual water components that allow to investigate effects of weather and weather variability on water mobilization. Based on the SSY analysis we infer individual water components responsible for sediment mobilization. We combine these findings in a coupled hydrology-erosion model approach to elucidate the complex underlying mechanisms

  13. Squeezing of Particle Distributions by Expanding Magnetic Turbulence and Space Weather Variability

    NASA Astrophysics Data System (ADS)

    Ruffolo, D. J.; Tooprakai, P.; Seripienlert, A.; Chuychai, P.; Matthaeus, W. H.

    2014-12-01

    Among the space weather effects due to gradual solar storms, greatly enhanced high-energy ion fluxes can cause radiation damage to satellites, spacecraft, and astronauts, which motivates examination of the transport of high-energy solar ions to Earth orbit. Ions of low kinetic energy (up to ˜2sim 2 MeV/nucleon) from impulsive solar events exhibit abrupt changes due to filamentation of magnetic connection from the Sun, indicating that anisotropic, field-aligned magnetic flux tube-like structures persist to Earth orbit. By employing a corresponding spherical two-component model of Alfv'enic (slab) and 2D magnetic fluctuations to trace simulated trajectories in the solar wind, we show that the distribution of high-energy (E≥1Egeq1 GeV) protons from gradual solar events is squeezed toward magnetic flux structures with a specific polarity due to the conical shape of the flux structures, which results from the expanding flow of the solar wind. It is difficult to observationally determine what polarity of flux structure the Earth is in at a given time, so this transport phenomenon contributes to event-to-event variability in ground level enhancements of GeV-range ions from solar storms, presenting a fundamental uncertainty in space weather prediction. Partially supported by the Thailand Research Fund, a Postdoctoral Fellowship from the Thailand Center of Excellence in Physics, a Research Fellowship from the Faculty of Science, Mahidol University, the U.S. NSF (AGS-1063439 and SHINE AGS-1156094), NASA (Heliophysics Theory NNX08AI47G & NNX11AJ44G), and the Solar Probe Plus/ISIS project. KEYWORDS: [7807] SPACE PLASMA PHYSICS / Charged particle motion and acceleration, [7863] SPACE PLASMA PHYSICS / Turbulence, [2118] INTERPLANETARY PHYSICS / Energetic particles, solar, [7984] SPACE WEATHER / Space radiation environment

  14. Influence of Weather Variables and Plant Communities on Grasshopper Density in the Southern Pampas, Argentina

    PubMed Central

    de Wysiecki, María Laura; Arturi, Marcelo; Torrusio, Sandra; Cigliano, María Marta

    2011-01-01

    temperature had no significant effect on total grasshopper density, these weather variables and plant communities had differential influence on the dominant grasshopper species. PMID:22220572

  15. Spatial and temporal wind variability over Spain and its relationship with synoptic weather types

    NASA Astrophysics Data System (ADS)

    Lorente-Plazas, R.; Montavez, J. P.; García-Valero, J. A.; Gómez-Navarro, J. J.; Jerez, S.; Baró, R.; Jiménez, P. A.; Jiménez-Guerrero, P.

    2012-04-01

    The knowledge of the spatial and temporal variability of the wind over a given area is crucial for multiple purposes, like wind power generation, pollutant dispersion, risk evaluation, hydrological processes, etc. On the other hand, the assessment of the synoptic conditions related to wind behavior can be very useful for several applications. In the framework of wind power, integrating the effects of large-scale on wind behavior could improve the scheduling of the power generation, as well as to avoid damage in wind turbines due to extreme wind events. In this work, we present a methodology which contributes to the improvement in wind energy profits manly in two aspects. By one hand, performing an objective wind regionalization of an extensive area allows the identification of complementary regions. On the other hand, the association of wind field to WT can be used as a convenient tool for medium-range weather forecast, as well as to perform future wind projections under different climate change scenarios. We have analyzed the wind variability using a network of 448 wind observations evenly distributed over Spain (except Canary Islands). The first step was to obtain regions with similar temporal behavior. This was performed by using a clustering method based on the main principal modes of variability, obtained through PCA analysis. The hierarchical Ward`s method is used to provide the initial seeds to a subsequent no-hirarchical k-means method. The analysis was carried out for daily mean series of wind speed encompassing the period 2001-2007, considering each season separately. The number of regions obtained with a similar wind speed behaviour depends on the season (8 in winter, 7 in spring, 6 in summer and autumn, and 13 for the whole year). The common regions in all seasons can be roughly associated to the following areas: High Ebro Valley, Low Ebro Valley, the Mediterranean Basin, the Guadalquivir Valley, the Cantabrian Coast and the Iberian Plateaus. It is

  16. New Jersey Tide Telemetry System

    USGS Publications Warehouse

    Hoppe, Heidi L.

    2007-01-01

    Each summer the population of the barrier-island communities of New Jersey increases by tens of thousands. When a coastal storm threatens these communities, the limited number of bridges and causeways that connect the islands with the mainland become overcrowded, making evacuations from the barrier islands to the mainland difficult. Timely evacuation depends on well-defined emergency evacuation plans used in conjunction with accurate flood forecasting and up to the minute (real-time) tide-level information. The 'Great Nor'easter' storm that struck the coastal areas of New Jersey on December 11, 1992, caused about $270 million in insured damages to public and private property (Dorr and others, 1995). Most of the damage was due to tidal flooding and storm surge, which were especially severe along the back bay areas. Comprehensive and reliable tide-level and meteorological data for the back bays was needed to make accurate flood forecasts. Collection of tidal data for the ocean and large bays was adequately covered by the National Oceanic and Atmospheric Administration's National Ocean Service (NOAA's NOS), but in New Jersey little to no data are available for the back-bay areas. The back bays behave quite differently than the ocean as a result of the complex interaction between the winds and the geometry of the inlets and bays. A slow moving Nor'easter can keep tide levels in back bays several feet higher than the ocean tide by not allowing tides to recede, resulting in flooding of bridges and causeways that link the barrier islands to the mainland. The U.S. Geological Survey (USGS), in cooperation with the New Jersey Department of Transportation (NJDOT), designed and installed the New Jersey Tide Telemetry System (NJTTS) with assistance from NOAA's NOS in 1997. This system is part of a statewide network of tide gages, weather stations, and stream gages that collect data in real time. The NJTTS supplies comprehensive, reliable real-time tide-level and meteorological

  17. Squeezing of Particle Distributions by Expanding Magnetic Turbulence and Space Weather Variability

    NASA Astrophysics Data System (ADS)

    Ruffolo, D.; Seripienlert, A.; Tooprakai, P.; Chuychai, P.; Matthaeus, W. H.

    2013-12-01

    Among the space weather effects due to gradual solar storms, greatly enhanced high-energy ion fluxes contribute to radiation damage to satellites, spacecraft, and astronauts and dominate the hazards to air travelers, which motivates examination of the transport of high-energy solar ions to Earth's orbit. Ions of low kinetic energy (up to ~2 MeV nucleon-1) from impulsive solar events exhibit abrupt changes due to filamentation of the magnetic connection from the Sun, indicating that anisotropic, field-aligned magnetic flux tubelike structures persist to Earth's orbit. By employing a corresponding spherical two-component model of Alfvénic (slab) and two-dimensional magnetic fluctuations to trace simulated trajectories in the solar wind, we show that the distribution of high-energy (E >= 1 GeV) protons from gradual solar events is squeezed toward magnetic flux structures with a specific polarity because of the conical shape of the flux structures. Conical flux structures and the squeezing of energetic particle distributions should occur in any astrophysical wind or jet with expanding, magnetized, turbulent plasma. This transport phenomenon contributes to event-to-event variability in ground level enhancements of GeV-range ions from solar storms, presenting a fundamental uncertainty in space weather prediction.

  18. Plant development scores from fixed-date photographs: the influence of weather variables and recorder experience

    NASA Astrophysics Data System (ADS)

    Sparks, T. H.; Huber, K.; Croxton, P. J.

    2006-05-01

    In 1944, John Willis produced a summary of his meticulous record keeping of weather and plants over the 30 years 1913 1942. This publication contains fixed-date, fixed-subject photography taken on the 1st of each month from January to May, using as subjects snowdrop Galanthus nivalis, daffodil Narcissus pseudo-narcissus, horse chestnut Aesculus hippocastanum and beech Fagus sylvatica. We asked 38 colleagues to assess rapidly the plant development in each of these photographs according to a supplied five-point score. The mean scores from this exercise were assessed in relation to mean monthly weather variables preceding the date of the photograph and the consistency of scoring was examined according to the experience of the recorders. Plant development was more strongly correlated with mean temperature than with minimum or maximum temperatures or sunshine. No significant correlations with rainfall were detected. Whilst mean scores were very similar, botanists were more consistent in their scoring of developmental stages than non-botanists. However, there was no overall pattern for senior staff to be more consistent in scoring than junior staff. These results suggest that scoring of plant development stages on fixed dates could be a viable method of assessing the progress of the season. We discuss whether such recording could be more efficient than traditional phenology, especially in those sites that are not visited regularly and hence are less amenable to frequent or continuous observation to assess when a plant reaches a particular growth stage.

  19. Plant development scores from fixed-date photographs: the influence of weather variables and recorder experience.

    PubMed

    Sparks, T H; Huber, K; Croxton, P J

    2006-05-01

    In 1944, John Willis produced a summary of his meticulous record keeping of weather and plants over the 30 years 1913-1942. This publication contains fixed-date, fixed-subject photography taken on the 1st of each month from January to May, using as subjects snowdrop Galanthus nivalis, daffodil Narcissus pseudo-narcissus, horse chestnut Aesculus hippocastanum and beech Fagus sylvatica. We asked 38 colleagues to assess rapidly the plant development in each of these photographs according to a supplied five-point score. The mean scores from this exercise were assessed in relation to mean monthly weather variables preceding the date of the photograph and the consistency of scoring was examined according to the experience of the recorders. Plant development was more strongly correlated with mean temperature than with minimum or maximum temperatures or sunshine. No significant correlations with rainfall were detected. Whilst mean scores were very similar, botanists were more consistent in their scoring of developmental stages than non-botanists. However, there was no overall pattern for senior staff to be more consistent in scoring than junior staff. These results suggest that scoring of plant development stages on fixed dates could be a viable method of assessing the progress of the season. We discuss whether such recording could be more efficient than traditional phenology, especially in those sites that are not visited regularly and hence are less amenable to frequent or continuous observation to assess when a plant reaches a particular growth stage. PMID:16402207

  20. Squeezing of particle distributions by expanding magnetic turbulence and space weather variability

    SciTech Connect

    Ruffolo, D.; Seripienlert, A.; Tooprakai, P.; Chuychai, P.; Matthaeus, W. H. E-mail: achara.ser@mahidol.ac.th E-mail: p.chuychai@sci.mfu.ac.th

    2013-12-10

    Among the space weather effects due to gradual solar storms, greatly enhanced high-energy ion fluxes contribute to radiation damage to satellites, spacecraft, and astronauts and dominate the hazards to air travelers, which motivates examination of the transport of high-energy solar ions to Earth's orbit. Ions of low kinetic energy (up to ∼2 MeV nucleon{sup –1}) from impulsive solar events exhibit abrupt changes due to filamentation of the magnetic connection from the Sun, indicating that anisotropic, field-aligned magnetic flux tubelike structures persist to Earth's orbit. By employing a corresponding spherical two-component model of Alfvénic (slab) and two-dimensional magnetic fluctuations to trace simulated trajectories in the solar wind, we show that the distribution of high-energy (E ≥ 1 GeV) protons from gradual solar events is squeezed toward magnetic flux structures with a specific polarity because of the conical shape of the flux structures. Conical flux structures and the squeezing of energetic particle distributions should occur in any astrophysical wind or jet with expanding, magnetized, turbulent plasma. This transport phenomenon contributes to event-to-event variability in ground level enhancements of GeV-range ions from solar storms, presenting a fundamental uncertainty in space weather prediction.

  1. Using Space Weather Variability in Evaluating the Radiation Environment Design Specifications for NASA's Constellation Program

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria N.; Blackwell, William C.; Minow, Joseph I.; Bruce, Margaret B.; Howard, James W.

    2007-01-01

    NASA's Constellation program, initiated to fulfill the Vision for Space Exploration, will create a new generation of vehicles for servicing low Earth orbit, the Moon, and beyond. Space radiation specifications for space system hardware are necessarily conservative to assure system robustness for a wide range of space environments. Spectral models of solar particle events and trapped radiation belt environments are used to develop the design requirements for estimating total ionizing radiation dose, displacement damage, and single event effects for Constellation hardware. We first describe the rationale using the spectra chosen to establish the total dose and single event design environmental specifications for Constellation systems. We then compare variability of the space environment to the spectral design models to evaluate their applicability as conservative design environments and potential vulnerabilities to extreme space weather events

  2. Effects of Weather Variables on Ascospore Discharge from Fusarium graminearum Perithecia

    PubMed Central

    Manstretta, Valentina; Rossi, Vittorio

    2015-01-01

    Fusarium graminearum is a predominant component of the Fusarium head blight (FHB) complex of small grain cereals. Ascosporic infection plays a relevant role in the spread of the disease. A 3-year study was conducted on ascospore discharge. To separate the effect of weather on discharge from the effect of weather on the production and maturation of ascospores in perithecia, discharge was quantified with a volumetric spore sampler placed near maize stalk residues bearing perithecia with mature ascospores; the residues therefore served as a continuous source of ascospores. Ascospores were discharged from perithecia on 70% of 154 days. Rain (R) and vapor pressure deficit (VPD) were the variables that most affected ascospore discharge, with 84% of total discharges occurring on days with R≥0.2 mm or VPD≤11 hPa, and with 70% of total ascospore discharge peaks (≥ 30 ascospores/m3 air per day) occurring on days with R≥0.2 mm and VPD≤6.35 hPa. An ROC analysis using these criteria for R and VPD provided True Positive Proportion (TPP) = 0.84 and True Negative Proportion (TNP) = 0.63 for occurrence of ascospore discharge, and TPP = 0.70 and TNP = 0.89 for occurrence of peaks. Globally, 68 ascospores (2.5% of the total ascospores sampled) were trapped on the 17 days when no ascospores were erroneously predicted. When a discharge occurred, the numbers of F. graminearum ascospores sampled were predicted by a multiple regression model with R2 = 0.68. This model, which includes average and maximum temperature and VPD as predicting variables, slightly underestimated the real data and especially ascospore peaks. Numbers of ascospores in peaks were best predicted by wetness duration of the previous day, minimum temperature, and VPD, with R2 = 0.71. These results will help refine the epidemiological models used as decision aids in FHB management programs. PMID:26402063

  3. Analysis of the influence of rainfall variables on urban effluents concentrations and fluxes in wet weather

    NASA Astrophysics Data System (ADS)

    Gooré Bi, Eustache; Monette, Frédéric; Gasperi, Johnny

    2015-04-01

    Urban rainfall runoff has been a topic of increasing importance over the past years, a result of both the increase in impervious land area arising from constant urban growth and the effects of climate change on urban drainage. The main goal of the present study is to assess and analyze the correlations between rainfall variables and common indicators of urban water quality, namely event mean concentrations (EMCs) and event fluxes (EFs), in order to identify and explain the impacts of each of the main rainfall variables on the generation process of urban pollutants during wet periods. To perform this analysis, runoff from eight summer rainfall events that resulted in combined sewer overflow (CSO) was sampled simultaneously from two distinct catchment areas in order to quantify discharges at the respective outfalls. Pearson statistical analysis of total suspended solids (TSS), chemical oxygen demand (COD), carbonaceous biochemical oxygen demand at 5 days (CBOD5), total phosphorus (Ptot) and total kedjal nitrogen (N-TKN) showed significant correlations (ρ = 0.05) between dry antecedent time (DAT) and EMCs on one hand, and between total rainfall (TR) and the volume discharged (VD) during EFs, on the other. These results show that individual rainfall variables strongly affect either EMCs or EFs and are good predictors to consider when selecting variables for statistical modeling of urban runoff quality. The results also show that in a combined sewer network, there is a linear relationship between TSS event fluxes and COD, CBOD5, Ptot, and N-TKN event fluxes; this explains 97% of the variability of these pollutants which adsorb onto TSS during wet weather, which therefore act as tracers. Consequently, the technological solution selected for TSS removal will also lead to a reduction of these pollutants. Given the huge volumes involved, urban runoffs contribute substantially to pollutant levels in receiving water bodies, a situation which, in a climate change context, may

  4. Implications of Non-Systematic Observations for Verification of Forecasts of Aviation Weather Variables

    NASA Astrophysics Data System (ADS)

    Brown, B. G.; Young, G. S.; Fowler, T. L.

    2001-12-01

    Over the last several years, efforts have been undertaken to develop improved automated forecasts of weather phenomena that have large impacts on aviation, including turbulence and in-flight icing conditions. Verification of these forecasts - which has played a major role in their development - is difficult due to the nature of the limited observations available for these evaluations; in particular, voice reports by pilots (PIREPs). These reports, which are provided inconsistently by pilots, currently are the best observations of turbulence and in-flight icing conditions available. However, their sampling characteristics make PIREPs a difficult dataset to use for these evaluations. In particular, PIREPs have temporal and spatial biases (e.g., they are more frequent during daylight hours, and they occur most frequently along flight routes and in the vicinity of major airports, where aircraft are concentrated), and they are subjective. Most importantly, the observations are non-systematic. That is, observations are not consistently reported at the same location and time. This characteristic of the reports has numerous implications for the verification of forecasts of these phenomena. In particular, it is inappropriate to estimate certain common verification statistics that normally are of interest in forecast evaluations. For example, estimates of the false alarm ratio and critical success index are incorrect, due to the unrepresentativeness of the observations. Analytical explanations for this result have been developed, and the magnitudes of the errors associated with estimating these statistics have been estimated through Monte Carlo simulations. In addition, several approaches have been developed to compensate for these characteristics of PIREPs in verification studies, including methods for estimating confidence intervals for the verification statistics, which take into account their sampling variability. These approaches also have implications for verification

  5. How reliable is the offline linkage of Weather Research & Forecasting Model (WRF) and Variable Infiltration Capacity (VIC) model?

    EPA Science Inventory

    The aim for this research is to evaluate the ability of the offline linkage of Weather Research & Forecasting Model (WRF) and Variable Infiltration Capacity (VIC) model to produce hydrological, e.g. evaporation (ET), soil moisture (SM), runoff, and baseflow. First, the VIC mo...

  6. Do weather changes influence pain levels in women with fibromyalgia, and can psychosocial variables moderate these influences?

    PubMed

    Smedslund, Geir; Eide, Hilde; Kristjansdottir, Ólöf Birna; Nes, Andrea Aparecida Gonçalves; Sexton, Harold; Fors, Egil A

    2014-09-01

    The aim of this study was to examine the association between fibromyalgia pain and weather, and to investigate whether psychosocial factors influence this relationship. Women with chronic widespread pain/fibromyalgia (N = 50) enrolled in a larger study, were recruited from a 4-week inpatient rehabilitation program in Norway ( 2009-2010), and reported their pain and psychological factors up to three times per day (morning, afternoon, evening) for 5 weeks. These ratings were then related to the official local weather parameters. Barometric pressure recorded simultaneously impacted pain significantly while temperature, relative humidity, and solar flux did not. No psychological variables influenced the weather-pain interaction. No weather parameter predicted change in the subsequent pain measures. The magnitude of the inverse association between pain and barometric pressure was very small, and none of the psychological variables studied influenced the association between pain and barometric pressure. All in all, the evidence for a strong weather-pain association in fibromyalgia seems limited at best. PMID:24132549

  7. Do weather changes influence pain levels in women with fibromyalgia, and can psychosocial variables moderate these influences?

    NASA Astrophysics Data System (ADS)

    Smedslund, Geir; Eide, Hilde; Kristjansdottir, Ólöf Birna; Nes, Andrea Aparecida Gonçalves; Sexton, Harold; Fors, Egil A.

    2014-09-01

    The aim of this study was to examine the association between fibromyalgia pain and weather, and to investigate whether psychosocial factors influence this relationship. Women with chronic widespread pain/fibromyalgia ( N = 50) enrolled in a larger study, were recruited from a 4-week inpatient rehabilitation program in Norway ( 2009-2010), and reported their pain and psychological factors up to three times per day (morning, afternoon, evening) for 5 weeks. These ratings were then related to the official local weather parameters. Barometric pressure recorded simultaneously impacted pain significantly while temperature, relative humidity, and solar flux did not. No psychological variables influenced the weather-pain interaction. No weather parameter predicted change in the subsequent pain measures. The magnitude of the inverse association between pain and barometric pressure was very small, and none of the psychological variables studied influenced the association between pain and barometric pressure. All in all, the evidence for a strong weather-pain association in fibromyalgia seems limited at best.

  8. Climate Variability and Weather Extremes: Model-Simulated and Historical Data. Chapter 9

    NASA Technical Reports Server (NTRS)

    Schubert, Siegfried D.; Lim, Young-Kwon

    2012-01-01

    Extremes in weather and climate encompass a wide array of phenomena including tropical storms, mesoscale convective systems, snowstorms, floods, heat waves, and drought. Understanding how such extremes might change in the future requires an understanding of their past behavior including their connections to large-scale climate variability and trends. Previous studies suggest that the most robust findings concerning changes in short-term extremes are those that can be most directly (though not completely) tied to the increase in the global mean temperatures. These include the findings that (IPCC 2007): There has been a widespread reduction in the number of frost days in mid-latitude regions in recent decades, an increase in the number of warm extremes, particularly warm nights, and a reduction in the number of cold extremes, particularly cold nights. For North America in particular (CCSP SAP 3.3, 2008): There are fewer unusually cold days during the last few decades. The last 10 years have seen a lower number of severe cold waves than for any other 10-year period in the historical record that dates back to 1895. There has been a decrease in the number of frost days and a lengthening of the frost-free season, particularly in the western part of North America. Other aspects of extremes such as the changes in storminess have a less clear signature of long term change, with considerable interannual, and decadal variability that can obscure any climate change signal. Nevertheless, regarding extratropical storms (CCSP SAP 3.3, 2008): The balance of evidence suggests that there has been a northward shift in the tracks of strong low pressure systems (storms) in both the North Atlantic and North Pacific basins. For North America: Regional analyses suggest that there has been a decrease in snowstorms in the South and lower Midwest of the United States, and an increase in snowstorms in the upper Midwest and Northeast. Despite the progress already made, our understanding of the

  9. California Coastal Low Clouds: Variability and Influences across Climate to Weather and Continental to Local Scales

    NASA Astrophysics Data System (ADS)

    Schwartz, Rachel E.

    Low coastal stratiform clouds (stratus, stratocumulus, and fog), referred to here as coastal low cloudiness (CLC), are a persistent seasonal feature of continental west coasts, including California. The importance of CLC ranges across fields, with applications ranging from solar resource forecasting, growth of endemic species, and heat wave expression and related health impacts. This dissertation improves our understanding of California's summertime CLC by describing its variability and influences on a range of scales from multidecadal to daily and continental to local. A novel achievement is the development of a new 19-year satellite-derived low cloud record. Trained on airport observations, this high resolution record plays a critical role in the description of CLC at finer spatial and shorter timescales. Observations at coastal airports from Alaska to southern California reveal coherent interannual to interdecadal variation of CLC. The leading mode of CLC variability, accounting for nearly 40% of the total variance, and the majority of individual airports, exhibit decreasing low cloudiness from 1950 to 2012. The coherent patterns of CLC variability are organized by North Pacific Sea Surface Temperature (SST) anomalies, linked to the Pacific Decadal Oscillation (PDO). The new satellite-derived low cloud retrieval reveals, in rich spatial texture, considerable variability in CLC within May-September. The average maximum cloudiness moves northward along the coast, from northern Baja, Mexico to northern California, from May to early August. Both component parts of lower tropospheric stability (LTS), SST and free-troposphere temperature, control this seasonal movement. The peak timing of cloudiness and daytime maximum temperatures are most closely aligned in northern California. On weather timescales, daily CLC anomalies are most strongly related to stability anomalies to the north (climatologically upwind) of the CLC region. CLC is strongly linked to stability in

  10. GFDL's unified regional-global weather-climate modeling system with variable resolution capability for severe weather predictions and regional climate simulations

    NASA Astrophysics Data System (ADS)

    Lin, S. J.

    2015-12-01

    The NOAA/Geophysical Fluid Dynamics Laboratory has been developing a unified regional-global modeling system with variable resolution capabilities that can be used for severe weather predictions (e.g., tornado outbreak events and cat-5 hurricanes) and ultra-high-resolution (1-km) regional climate simulations within a consistent global modeling framework. The fundation of this flexible regional-global modeling system is the non-hydrostatic extension of the vertically Lagrangian dynamical core (Lin 2004, Monthly Weather Review) known in the community as FV3 (finite-volume on the cubed-sphere). Because of its flexability and computational efficiency, the FV3 is one of the final candidates of NOAA's Next Generation Global Prediction System (NGGPS). We have built into the modeling system a stretched (single) grid capability, a two-way (regional-global) multiple nested grid capability, and the combination of the stretched and two-way nests, so as to make convection-resolving regional climate simulation within a consistent global modeling system feasible using today's High Performance Computing System. One of our main scientific goals is to enable simulations of high impact weather phenomena (such as tornadoes, thunderstorms, category-5 hurricanes) within an IPCC-class climate modeling system previously regarded as impossible. In this presentation I will demonstrate that it is computationally feasible to simulate not only super-cell thunderstorms, but also the subsequent genesis of tornadoes using a global model that was originally designed for century long climate simulations. As a unified weather-climate modeling system, we evaluated the performance of the model with horizontal resolution ranging from 1 km to as low as 200 km. In particular, for downscaling studies, we have developed various tests to ensure that the large-scale circulation within the global varaible resolution system is well simulated while at the same time the small-scale can be accurately captured

  11. What Causes Tides?

    ERIC Educational Resources Information Center

    Donovan, Deborah

    2004-01-01

    The phenomenon of tides has a faraway source. This rise and fall of the water level over a period of several hours is a result of the gravitational pull of the Moon and the Sun on Earth's oceans. Tides exhibit predictable cycles on daily, monthly, and yearly scales. The magnitude of the tides is dependent on the position of the Earth and Moon in…

  12. A method to assess the inter-annual weather-dependent variability in air pollution concentration and deposition based on weather typing

    NASA Astrophysics Data System (ADS)

    Pleijel, Håkan; Grundström, Maria; Karlsson, Gunilla Pihl; Karlsson, Per Erik; Chen, Deliang

    2016-02-01

    Annual anomalies in air pollutant concentrations, and deposition (bulk and throughfall) of sulphate, nitrate and ammonium, in the Gothenburg region, south-west Sweden, were correlated with optimized linear combinations of the yearly frequency of Lamb Weather Types (LWTs) to determine the extent to which the year-to-year variation in pollution exposure can be partly explained by weather related variability. Air concentrations of urban NO2, CO, PM10, as well as O3 at both an urban and a rural monitoring site, and the deposition of sulphate, nitrate and ammonium for the period 1997-2010 were included in the analysis. Linear detrending of the time series was performed to estimate trend-independent anomalies. These estimated anomalies were subtracted from observed annual values. Then the statistical significance of temporal trends with and without LWT adjustment was tested. For the pollutants studied, the annual anomaly was well correlated with the annual LWT combination (R2 in the range 0.52-0.90). Some negative (annual average [NO2], ammonia bulk deposition) or positive (average urban [O3]) temporal trends became statistically significant (p < 0.05) when the LWT adjustment was applied. In all the cases but one (NH4 throughfall, for which no temporal trend existed) the significance of temporal trends became stronger with LWT adjustment. For nitrate and ammonium, the LWT based adjustment explained a larger fraction of the inter-annual variation for bulk deposition than for throughfall. This is probably linked to the longer time scale of canopy related dry deposition processes influencing throughfall being explained to a lesser extent by LWTs than the meteorological factors controlling bulk deposition. The proposed novel methodology can be used by authorities responsible for air pollution management, and by researchers studying temporal trends in pollution, to evaluate e.g. the relative importance of changes in emissions and weather variability in annual air pollution

  13. Impact of selected personal factors on seasonal variability of recreationist weather perceptions and preferences in Warsaw (Poland)

    NASA Astrophysics Data System (ADS)

    Lindner-Cendrowska, Katarzyna; Błażejczyk, Krzysztof

    2016-08-01

    Weather and climate are important natural resources for tourism and recreation, although sometimes they can make outdoor leisure activities less satisfying or even impossible. The aim of this work was to determine weather perception seasonal variability of people staying outdoors in urban environment for tourism and recreation, as well as to determine if personal factors influence estimation of recreationist actual biometeorological conditions and personal expectations towards weather elements. To investigate how human thermal sensations vary upon meteorological conditions typical for temperate climate, weather perception field researches were conducted in Warsaw (Poland) in all seasons. Urban recreationists' preference for slightly warm thermal conditions, sunny, windless and cloudless weather, were identified as well as PET values considered to be optimal for sightseeing were defined between 27.3 and 31.7 °C. The results confirmed existence of phenomena called alliesthesia, which manifested in divergent thermal perception of comparable biometeorological conditions in transitional seasons. The results suggest that recreationist thermal sensations differed from other interviewees' responses and were affected not only by physiological processes but they were also conditioned by psychological factors (i.e. attitude, expectations). Significant impact of respondents' place of origin and its climate on creating thermal sensations and preferences was observed. Sex and age influence thermal preferences, whereas state of acclimatization is related with thermal sensations to some point.

  14. Dropouts, spreading, and squeezing of solar particle distributions and space weather variability

    NASA Astrophysics Data System (ADS)

    Matthaeus, W. H.; Ruffolo, D. J.; Seripienlert, A.; Tooprakai, P.; Chuychai, P.

    2015-12-01

    In the past 15 years, observations and theories concerning dropouts of solar energetic particles have made it clear that the lateral spread of field lines and particles from a given location near the Sun is not a purely diffusive process. Particles of low energy from impulsive solar events exhibit abrupt changes in flux (dropouts) due to filamentation of magnetic connection from the Sun, indicating that magnetic flux tube-like structures at least partially persist to Earth orbit. Our simulations based on a corresponding spherical two-component model of Alfvénic (slab) and 2D magnetic fluctuations indicate that such particles mostly follow field lines, which spread over ˜25° at Earth orbit, and exhibit dropout features. On the other hand, gradual solar events are of practical interest because they can produce greatly enhanced high-energy ion fluxes, which can cause radiation damage to satellites, spacecraft, and astronauts. While gradual events do not exhibit dropouts in the above sense, we show that the distribution of high-energy (E≥1 GeV) protons is squeezed toward magnetic flux tube-like structures with a specific polarity due to the structures' conical shape. Since it is difficult to observationally determine what polarity of flux structure the Earth is in at a given time, this transport phenomenon contributes to event-to-event variability in ground level enhancements of GeV-range ions from solar storms, presenting a fundamental uncertainty in space weather prediction. Partially supported by the Thailand Research Fund (Grant BRG5880009), a Postdoctoral Fellowship from the Thailand Center of Excellence in Physics, a Research Fellowship from the Faculty of Science at Mahidol University, the U.S. NSF (AGS-1063439 and SHINE AGS-1156094), NASA (Heliophysics Theory NNX14AI63G, and LWS NNX15AB88G), and the Solar Probe Plus/ISIS project (D99031L).

  15. Atmospheric Tides over the Pyrenees. Observational study and numerical simulation

    NASA Astrophysics Data System (ADS)

    Diaz de Argandoña, Javier; Ezcurra, Agustin; Saenz, Jon; Campistron, Bernard; Ibarra-Berastegi, Gabriel; Saïd, Frederique

    2010-05-01

    Atmospheric tides refer to the oscillations in the atmosphere whose periods are integral fractions of a day. In some magnitudes (e.g. temperature), these oscillations are quite evident but in others, such as the pressure in the midlatitudes, they are usually masked by the greater variations produced during the transient pass of synoptic weather systems. The main forcing agent for these oscillations, as opposed to ocean tides, is not the solar or lunar gravity pull, but the daily variations in solar insolation and the thermal effect derived from it. The main components of the solar atmospheric tides are the semidiurnal, with a 12-hour period, and the 24-hour period component or diurnal tide. The global scale tides are usually referred to as migrating tides, and are the result of a gravity wave which travels westerly with the apparent motion of the sun. Nevertheless, a significant part of the tide can be related to local characteristics, and this part is considered as the non-migrating component of the tide. Barometric tides around the Pyrenees mountain range are analyzed by means of ground synoptic stations data recorded during one year, ground data from PYREX experiment and the CRA/LA VHF wind profiler installed in the North of the range. Tides are decomposed in their diurnal and semidiurnal components. Diurnal tides show a strong non migrating component and are very dependent on local conditions. Semidiurnal tides are more homogeneous and present a north-south asymmetry, also noted in the Alps. This cross-range asymmetry seems to be related to some interference effect caused by the mountain range in the migrating semidiurnal tide wave. The diurnal component asymmetry presents a very strong seasonal variation, so its cause must be probably related to thermal local conditions. A three month simulation carried out with NCAR's WRF limited area model reproduces this asymmetry and some of the features of the observed tides.

  16. Non-systematic weathering profile in the Blue Ridge Mountains, N. C. : Role of geochemical variables

    SciTech Connect

    Ciampone, M.A.; McVey, D.E.; Gerke, T.L.; Briggs, W.D.; Zhang, Yangsheng; Maynard, J.B.; Huff, W.D. . Dept. of Geology)

    1992-01-01

    Weathering profiles from representative cores of the Coweeta Group, schist, and Tallulah Falls Fm, gneiss, in the Blue Ridge Mountains of North Carolina were examined. The predominant alteration minerals, which formed from the partial alteration of biotite and plagioclase, include kaolinite, chlorite, vermiculite interstratified with biotite, gibbsite. These mineral phases were identified using petrographic observation, SEM, X-ray diffraction, and selected electron microprobe analysis. These minerals commonly represent a weathering profile (developed from surface to depth on a single source rock) ranging from mature (gibbsite), to intermediate (kaolinite + interlayered biotite/vermiculite), to immature (plagioclase + biotite) at depth. In this study, however, there is no clear vertical zonation of the weathering profile. This indicates a more selective weathering process than would typically be assumed. This nonsystematic weathering profile may reflect variations in bulk composition of the parent rock and/or variations in the composition of ground water. The presence and abundance of gibbsite in these weathering profiles is unusual because it is normally associated with bauxite in which the Al[sub 2]O[sub 3] content is > 80 wt.%. In this study the Al[sub 2]O[sub 3] content of the regolith is approximately 20 wt.%. The presence of gibbsite emphasizes the importance of solution-reprecipitation of Al-rich phases as an independent process in temperature climates, and suggests the activity of silica is more critical than regional climatological effects in controlling regolith formation.

  17. a Study of Risk Preferences and Perceptions of Weather Variability of Smallholder Subsistence Farmers in Malawi

    NASA Astrophysics Data System (ADS)

    Yoon, S.; Michelson, H. C.

    2013-12-01

    called parametric Dynamic Experiments for Estimating Preferences developed at Columbia University to measure three prospect theory parameters using an adaptive survey tool installed on a tablet PC. Our work is the first to use an adaptive survey tool to measure risk preferences and to combine these measures with both panel data on agricultural investments and beliefs about climate change using scenarios. Despite the need for better understanding of how farmer preferences over time and risk might influence technology adoption and production decisions made by farmers in sub-Saharan Africa, there is a critical gap in research about this topic. Whether and how vulnerability to climate change has entered the mind frame of farmers is explored with a scenario setup, in which farmers are asked to provide advice to a hypothetical farmer facing low yields due to a prolonged drought. Farmer responses to the scenarios give us information about both the channel through which farmers receive information about agriculture and adaptation and primary factors mentioned to be important agricultural strategies in the face of increasingly unpredictable weather patterns. This research offers insights to understand decision-making process of smallholder farmers, who face adverse effects of weather variability and the present problem of low soil fertility.

  18. Variability of the essential oil content and composition of chamomile (Matricaria recutita L.) affected by weather conditions.

    PubMed

    Gosztola, Beáta; Sárosi, Szilvia; Németh, Eva

    2010-03-01

    In our study we examined the variability of the essential oil content and composition of chamomile (Matricaria recutita L.) during three years (2005-2007). Twenty-eight populations of wild origin and 4 registered cultivars ('Soroksári 40', 'Lutea', 'Goral' and 'Bona') were evaluated in open field experiments. It could be established that the experimental populations represented different genetic potential for essential oil accumulation and composition. The best populations of wild growing origin from the Somogy-region and four cultivars produced the highest essential oil contents (above 0.6 g/100g) in each year. Additionally, the quality of the characteristic main compound of the oil determining the "chemotype", according to Schilcher, was found to be stable during the three years period. However, the actual chemosyndroms are significantly influenced by the weather conditions. In the three years' experiment, the moderately warm and relatively wet year of 2006 produced the highest contents of essential oil and also that of its alpha-bisabolol component. Although bisabolol oxide A also showed a high variability through the years, its direct connection with weather conditions could not be proved. A moderate variability was established for the proportions of chamazulene, and the lowest one for bisabolol-oxide B. Considerable genotype-weather interaction was supposed, especially for the essential oil content and for the ratio of bisabolol-oxide A. PMID:20420329

  19. MST radar detection of middle atmosphere tides

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1983-01-01

    Meteorological and dynamical requirements pertaining to the specification of middle atmosphere tides by the MST radar technique are outlined. Major issues addressed include: (1) the extraction of tidal information from measurements covering a fraction of a day; (2) the ramifications of transient effects (tidal variability) on the determination and interpretation of tides; (3) required temporal and spatial resolutions and; (4) global distributions of MST radars, so as to complement existing MST, meteor wind, and partial reflection drift radar locations.

  20. Oxidative weathering chemical migration under variably saturated conditions and supergene copper enrichment

    SciTech Connect

    Xu, Tianfu; Pruess, K.; Brimhall, G.

    1999-04-01

    Transport of oxygen gas from the land surface through an unsaturated zone has a strong influence on oxidative weathering processes. Oxidation of sulfide minerals such as pyrite (FeS{sub 2}), one of the most common naturally occurring minerals, is the primary source of acid drainage from mines and waste rock piles. Here we present a detailed numerical model of supergene copper enrichment that involves the oxidative weathering of pyrite (FeS{sub 2}) and chalcopyrite (CuFeS{sub 2}), and acidification that causes mobilization of metals in the unsaturated zone, with subsequent formation of enriched ore deposits of chalcocite (CuS) and covellite (Cu{sub 2}S) in the reducing conditions below the water table. We examine and identify some significant conceptual and computational issues regarding the oxidative weathering processes through the modeling tool. The dissolution of gaseous oxygen induced by the oxidation reduces oxygen partial pressure, as well as the total pressure of the gas phase. As a result, the gas flow is modified, then the liquid phase flow. Results indicate that this reaction effect on the fluid flow may not be important under ambient conditions, and gas diffusion can be a more important mechanism for oxygen supply than gas or liquid advection. Acidification, mobilization of metals, and alteration of primary minerals mostly take place in unsaturated zone (oxidizing), while precipitation of secondary minerals mainly occurs in saturated zone (reducing). The water table may be considered as an interface between oxidizing and reducing zones. Moving water table due to change of infiltration results in moving oxidizing zone and redistributing aqueous chemical constitutes and secondary mineral deposits. The oxidative weathering processes are difficult to model numerically, because concentrations of redox sensitive chemical species such as O{sub 2}(aq), SO{sub 4}{sup 2-} and HS{sup -} may change over tens of orders of magnitude between oxidizing and reducing

  1. Tide operated power generating apparatus

    SciTech Connect

    Kertzman, H. Z.

    1981-02-03

    An improved tide operated power generating apparatus is disclosed in which a hollow float, rising and falling with the ocean tide, transmits energy to a power generator. The improvement comprises means for filling the float with water during the incoming tide to provide a substantial increase in the float dead weight during the outgoing tide. Means are further provided to then empty the float before the outgoing tide whereby the float becomes free to rise again on the next incoming tide.

  2. Atmosphere-Ionosphere Coupling due to Atmospheric Tides (Julius Bartels Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Forbes, Jeffrey M.

    2016-04-01

    Within the last decade, a new realization has arrived on the scene of ionosphere-thermosphere (IT) science: terrestrial weather significantly influences space weather. The aspect of space weather referred to here consists of electron density variability that translates to uncertainties in navigation and communications systems, and neutral density variability that translates to uncertainties in orbital and reentry predictions. In the present context "terrestrial weather" primarily refers to the meteorological conditions that determine the spatial-temporal distribution of tropospheric water vapor and latent heating associated with tropical convection, and the middle atmosphere disturbances associated with sudden stratosphere warmings. The net effect of these processes is a spatially- and temporally-evolving spectrum of waves (gravity waves, tides, planetary waves, Kelvin waves) that grows in amplitude with height and enters the IT system near ~100 km. Some members of the wave spectrum penetrate all the way to the base of the exosphere (ca. 500 km). Along the way, nonlinear interactions between different wave components occur, modifying the interacting waves and giving rise to secondary waves. Finally, the IT wind perturbations carried by the waves can redistribute ionospheric plasma, either through the electric fields generated via the dynamo mechanism between 100 and 150 km, or directly by moving plasma along magnetic field lines at higher levels. Additionally, the signatures of wave-driven dynamo currents are reflected in magnetic perturbations observed at the ground. This is how terrestrial atmospheric variability, through the spectrum of vertically- propagating waves that it produces, can effectively drive IT space weather. The primary objective of this Julius Bartels Lecture is to provide an overview of the global observational evidence for the IT consequences of these upward-propagating waves. In honor of Julius Bartels, who performed much research (including

  3. The potential impacts of climate variability and change on health impacts of extreme weather events in the United States.

    PubMed Central

    Greenough, G; McGeehin, M; Bernard, S M; Trtanj, J; Riad, J; Engelberg, D

    2001-01-01

    Extreme weather events such as precipitation extremes and severe storms cause hundreds of deaths and injuries annually in the United States. Climate change may alter the frequency, timing, intensity, and duration of these events. Increases in heavy precipitation have occurred over the past century. Future climate scenarios show likely increases in the frequency of extreme precipitation events, including precipitation during hurricanes, raising the risk of floods. Frequencies of tornadoes and hurricanes cannot reliably be projected. Injury and death are the direct health impacts most often associated with natural disasters. Secondary effects, mediated by changes in ecologic systems and public health infrastructure, also occur. The health impacts of extreme weather events hinge on the vulnerabilities and recovery capacities of the natural environment and the local population. Relevant variables include building codes, warning systems, disaster policies, evacuation plans, and relief efforts. There are many federal, state, and local government agencies and nongovernmental organizations involved in planning for and responding to natural disasters in the United States. Future research on health impacts of extreme weather events should focus on improving climate models to project any trends in regional extreme events and as a result improve public health preparedness and mitigation. Epidemiologic studies of health effects beyond the direct impacts of disaster will provide a more accurate measure of the full health impacts and will assist in planning and resource allocation. PMID:11359686

  4. A multivariate extreme wave and storm surge climate emulator based on weather patterns

    NASA Astrophysics Data System (ADS)

    Rueda, A.; Camus, P.; Tomás, A.; Vitousek, S.; Méndez, F. J.

    2016-08-01

    Coastal floods often coincide with large waves, storm surge and tides. Thus, joint probability methods are needed to properly characterize extreme sea levels. This work introduces a statistical downscaling framework for multivariate extremes that relates the non-stationary behavior of coastal flooding events to the occurrence probability of daily weather patterns. The proposed method is based on recently-developed weather-type methods to predict extreme events (e.g., significant wave height, mean wave period, surge level) from large-scale sea-level pressure fields. For each weather type, variables of interest are modeled using Generalized Extreme Value (GEV) distributions and a Gaussian copula for modelling the interdependence between variables. The statistical dependence between consecutive days is addressed by defining a climate-based extremal index for each weather type. This work allows attribution of extreme events to specific weather conditions, enhancing the knowledge of climate-driven coastal flooding.

  5. Phytoplankton variability in Lake Fraijanes, Costa Rica, in response to local weather variation.

    PubMed

    Umaña-Villalobos, Gerardo

    2014-06-01

    Phytoplankton species show a variety in morphology which is the result of adaptations to pelagic life including responses to fluctuations in water column dynamics driven by weather conditions. This has been reported in the oceans and in Northern temperate lakes. In order to observe whether tropical freshwater phytoplankton responds to seasonal variation in weather, the weekly variation in temperature of the water column and phytoplankton composition was studied in Lake Fraijanes, Costa Rica, a shallow (6.2m) lake at 1 640m above sea level. A chain of data loggers for temperature was placed in the deepest point in the lake to register temperature every hour at four different depths, and phytoplankton samples were retrieved every week for a year. Additional monthly samples for nutrients were taken at two depths. Notwithstanding its shallowness, the lake developed a thermal gradient which kept the water column stratified for several months during dry season. Whole lake overturns occurred during cold spells with intense precipitation. Phytoplankton changed throughout the year mainly through a shift in dominant taxa. From September to February the lake was frequently mixed by rain storms and windy weather. At this time, phytoplankton was dominated by Chlorococcal green algae. From March to June, the lake was stratified and warmer. Phytoplankton became dominated by Cyanobateria, mainly colonial Chroococcales. The rainy season started again in May 2009. During June and July the lake started to mix intermittently during rain events and phytoplankton showed a brief increase in the contribution of Chlorococcales. These changes fitted well to a general model of phytoplankton succession based on functional groups identified according to their morphology and adaptations. PMID:25102633

  6. Tides and tsunamis

    NASA Technical Reports Server (NTRS)

    Zetler, B. D.

    1972-01-01

    Although tides and tsunamis are both shallow water waves, it does not follow that they are equally amenable to an observational program using an orbiting altimeter on a satellite. A numerical feasibility investigation using a hypothetical satellite orbit, real tide observations, and sequentially increased levels of white noise has been conducted to study the degradation of the tidal harmonic constants caused by adding noise to the tide data. Tsunami waves, possibly a foot high and one hundred miles long, must be measured in individual orbits, thus requiring high relative resolution.

  7. Performance of weather research and forecasting model with variable horizontal resolution

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    In this paper, Weather Research and Forecasting (WRF) model is employed with three different horizontal grid spacings (45, 15 and 5 km) to assess the impact of horizontal resolution on short-range weather forecast. Simulations are carried out daily at 0000 UTC over the Indian region during the entire month of July 2011. A rigorous validation is performed against surface observations, radiosonde measurements and Tropical Rainfall Measuring Mission (TRMM) 3B42 merged rainfall product. Results show that horizontal resolution has a substantial impact on the WRF model forecast, particularly on the near surface temperature, moisture, winds and rainfall forecasts. Relative to 45-km horizontal grid spacing, 24-h forecasts of near surface temperature, moisture and winds are improved by ˜15, 9 and 4 %, respectively, when horizontal grid spacing is reduced to 5 km. Noteworthy improvement is also seen in the 24-h rainfall forecasts of the WRF model as the horizontal grid spacing decreased from 45 to 5 km. Larger improvements are observed over the Western Ghats and northeastern part of India compared to central India, which demonstrate the importance of finer resolution over the mountainous terrain compared to plains.

  8. The Earth Tides.

    ERIC Educational Resources Information Center

    Levine, Judah

    1982-01-01

    In addition to oceans, the earth is subjected to tidal stresses and undergoes tidal deformations. Discusses origin of tides, tidal stresses, and methods of determining tidal deformations (including gravity, tilt, and strain meters). (JN)

  9. Students' Understanding of Tides.

    ERIC Educational Resources Information Center

    Viiri, Jouni

    2000-01-01

    Reports the findings of research into students' understanding of tides. Students from secondary school and pre-service primary school teacher trainees were chosen as subjects and their understanding was assessed by questionnaire. (Author/CCM)

  10. Antarctic sea ice response to weather and climate modes of variability

    NASA Astrophysics Data System (ADS)

    Kohyama, Tsubasa

    The relationship between climate modes and Antarctic sea ice is explored by separating the variability into intraseasonal, interannual, and decadal time scales. Cross spectral analysis shows that geopotential height and Antarctic sea ice extent are most coherent at periods between about 20 and 40 days (the intraseasonal time scale). In this period range, where the atmospheric circulation and the sea ice extent are most tightly coupled, sea ice variability responds strongly to Rossby waves with the structure of the Pacific-South American (PSA) pattern. The PSA pattern in this time scale is not directly related to the El Nino Southern Oscillation (ENSO) nor the Southern Annular Mode (SAM), which have received much attention for explaining Antarctic sea ice variability. On the interannual time scale, ENSO and SAM are important, but a large fraction of sea ice variance can also be explained by Rossby wave-like structures in the Drake Passage region. After regressing out the sea ice extent variability associated with ENSO, the observed positive sea ice trends in Ross Sea and Indian Ocean during the satellite era become statistically insignificant. Regressing out SAM makes the sea ice trend in the Indian Ocean insignificant. Thus, the positive trends in sea ice in the Ross Sea and the Indian Ocean sectors may be explained by the variability and decadal trends of known interannual climate modes.

  11. Waves: Internal Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    1999-01-01

    Oceanic internal tides are internal waves with tidal periodicities. They are ubiquitous throughout the ocean, although generally more pronounced near large bathymetric features such as mid-ocean ridges and continental slopes. The internal vertical displacements associated with these waves can be extraordinarily large. Near some shelf breaks where the surface tides are strong, internal displacements (e.g., of an isothermal surface) can exceed 200 meters. Displacements of 10 meters in the open ocean are not uncommon. The associated current velocities are usually comparable to or larger than the currents of the surface tide. On continental shelves internal tides can occasionally generate packets of internal solitons, which are detectable in remote sensing imagery. Other common nonlinear features are generation of higher harmonics (e.g., 6-hr waves) and wave breaking. Internal tides are known to be an important energy source for mixing of shelf waters. Recent research suggests that they may also be a significant energy source for deep-ocean mixing.

  12. The Role of Gravity Waves in Modulating Atmospheric Tides

    NASA Technical Reports Server (NTRS)

    Mayr, H. G.; Mengel, J. G; Chan, K. L.; Porter, H. S.

    1999-01-01

    We discuss results for the diurnal and semidiurnal tides obtained from our 3-D, time dependent numerical spectral model (NMS), extending from the ground up into the thermosphere, which incorporates Hines' Doppler spread parameterization of small scale gravity waves (GW). In the DSP, GW momentum (and energy) are conserved as the waves modulate the background flow and are filtered by the flow.As a consequence, the GW interaction tightly couples the dynamic components of the middle atmosphere with strong non-linear interactions between mean zonal circulation, tides and planetary waves to produce complicated patterns of variability much like those observed. The major conclusions are: (1) Since GW momentum is deposited in the altitude regime of increasing winds, the amplitude of the diurnal tide is amplified and its vertical wavelength is reduced at altitudes between 80 and 120 km. Wave filtering by the mean zonal circulation (with peak velocities during solstice) causes the GW flux to peak during equinox, and this produces a large semi-annual variation in the tide that has been observed on UARS. (2) Without the diurnal tide, the semidiurnal tide would also be modulated in this way. But the diurnal tide filters out the GW preferentially during equinox, so that the semidiurnal tide, at higher altitudes, tends to peak during solstice. (3) Under the influence of GW, the tides are modulated also significantly by planetary waves, with periods between 2 and 30 days, which are generated preferentially during solstice in part due to baroclinic instability.

  13. Contribution of Sand-Associated Enterococci to Dry Weather Water Quality

    PubMed Central

    2015-01-01

    Culturable enterococci and a suite of environmental variables were collected during a predominantly dry summer at a beach impacted by nonpoint source pollution. These data were used to evaluate sands as a source of enterococci to nearshore waters, and to assess the relationship between environmental factors and dry-weather enterococci abundance. Best-fit multiple linear regressions used environmental variables to explain more than half of the observed variation in enterococci in water and dry sands. Notably, during dry weather the abundance of enterococci in dry sands at the mean high-tide line was significantly positively related to sand moisture content (ranging from <1–4%), and the daily mean ENT in water could be predicted by a linear regression with turbidity alone. Temperature was also positively correlated with ENT abundance in this study, which may indicate an important role of seasonal warming in temperate regions. Inundation by spring tides was the primary rewetting mechanism that sustained culturable enterococci populations in high-tide sands. Tidal forcing modulated the abundance of enterococci in the water, as both turbidity and enterococci were elevated during ebb and flood tides. The probability of samples violating the single-sample maximum was significantly greater when collected during periods with increased tidal range: spring ebb and flood tides. Tidal forcing also affected groundwater mixing zones, mobilizing enterococci from sand to water. These data show that routine monitoring programs using discrete enterococci measurements may be biased by tides and other environmental factors, providing a flawed basis for beach closure decisions. PMID:25479559

  14. Ocean Tide Loading Computation

    NASA Technical Reports Server (NTRS)

    Agnew, Duncan Carr

    2005-01-01

    September 15,2003 through May 15,2005 This grant funds the maintenance, updating, and distribution of programs for computing ocean tide loading, to enable the corrections for such loading to be more widely applied in space- geodetic and gravity measurements. These programs, developed under funding from the CDP and DOSE programs, incorporate the most recent global tidal models developed from Topex/Poscidon data, and also local tide models for regions around North America; the design of the algorithm and software makes it straightforward to combine local and global models.

  15. Dynamic Elastic Tides

    NASA Astrophysics Data System (ADS)

    Wisdom, Jack; Meyer, Jennifer

    2016-04-01

    This is an exploration of dynamic tides on elastic bodies. The body is thought of as a dynamical system described by its modes of oscillation. The dynamics of these modes are governed by differential equations that depend on the rheology. The modes are damped by dissipation. Tidal friction occurs as exterior bodies excite the modes and the modes act back on the tide raising body. The whole process is governed by a closed set of differential equations. Standard results from tidal theory are recovered in a two-timescale approximation to the solution of these differential equations.

  16. The effects of daily weather variables on psychosis admissions to psychiatric hospitals

    NASA Astrophysics Data System (ADS)

    McWilliams, Stephen; Kinsella, Anthony; O'Callaghan, Eadbhard

    2013-07-01

    Several studies have noted seasonal variations in admission rates of patients with psychotic illnesses. However, the changeable daily meteorological patterns within seasons have never been examined in any great depth in the context of admission rates. A handful of small studies have posed interesting questions regarding a potential link between psychiatric admission rates and meteorological variables such as environmental temperature (especially heat waves) and sunshine. In this study, we used simple non-parametric testing and more complex ARIMA and time-series regression analysis to examine whether daily meteorological patterns (wind speed and direction, barometric pressure, rainfall, sunshine, sunlight and temperature) exert an influence on admission rates for psychotic disorders across 12 regions in Ireland. Although there were some weak but interesting trends for temperature, barometric pressure and sunshine, the meteorological patterns ultimately did not exert a clinically significant influence over admissions for psychosis. Further analysis is needed.

  17. SUAVE: a UV telescope for space weather and solar variability studies

    NASA Astrophysics Data System (ADS)

    Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Keckhut, P.; Quémerais, E.

    2014-07-01

    SUAVE (Solar Ultraviolet Advanced Variability Experiment) is a far ultraviolet (FUV) imaging solar telescope of novel design for ultimate thermal stability and long lasting performances. SUAVE is a 90 mm Ritchey- Chrétien telescope with SiC (Silicon Carbide) mirrors and no entrance window for long and uncompromised observations in the UV (no coatings of mirrors, flux limited to less than a solar constant on filters to avoid degradation), associated with an ultimate thermal control (heat evacuation, focus control, stabilization). Design of the telescope and early thermal modeling leading to a representative breadboard (a R and T program supported by CNES) will be presented. SUAVE is the main instrument of the SUITS (Solar Ultraviolet Influence on Troposphere/Stratosphere) microsatellite mission, a small-size mission proposed to CNES and ESA.

  18. Assessing the cumulative effect of the weather variability on wetlands and the hydrological connection between wetlands and downstream waters

    NASA Astrophysics Data System (ADS)

    Yeo, I. Y.; Lang, M. W.; Lee, S.; Mccarty, G.; Peng, Y.; Huang, C.

    2014-12-01

    Wetlands are crucial ecosystem features that provide important ecological benefits to improve water quality and reduce the climate change impact. This ecosystem functioning of wetlands is largely dependent upon their hydrological characteristics and linkage to the downstream waters. However, the cumulative impacts of the climate on wetlands and the hydrological connection between wetlands and downstream waters have been rarely quantified at the landscape scale. This study reports findings from time series satellite observation that can illustrate the changes in extent of wetland inundation at a high spatial resolution (30-m) over the period 1985-2010. This remote sensing based observation provides crucial information to gain insights onto inter-annual variability of inundation dynamics, and we analyze this product with the drought indices, streamflows, the USFS NWI-hydrologic modifier. This study focuses on natural palustrine wetlands, densely distributed in the coastal plain of the Chesapeake Bay Watershed (CBW). We observe inundation patterns change in response to the weather variability, and it is proportionally related to the downstream flow discharge. While those wetlands with a longer hydro-period (i.e., permanently ponded wetlands during the growing season) show the strongest relationship with stream discharge (including baseflow, contributed from the shallow groundwater), inundation patterns of headwater/isolated wetlands are also strongly related to stream discharge. It shows the strong relationship between wetlands and downstream water regardless of geographic isolation and their mutual reliance on groundwater. The study provides the support for the conservation of wetlands through section 404 of the Clean Water Act.

  19. A Study of the Relationship between Weather Variables and Electric Power Demand inside a Smart Grid/Smart World Framework

    PubMed Central

    Hernández, Luis; Baladrón, Carlos; Aguiar, Javier M.; Calavia, Lorena; Carro, Belén; Sánchez-Esguevillas, Antonio; Cook, Diane J.; Chinarro, David; Gómez, Jorge

    2012-01-01

    One of the main challenges of today's society is the need to fulfill at the same time the two sides of the dichotomy between the growing energy demand and the need to look after the environment. Smart Grids are one of the answers: intelligent energy grids which retrieve data about the environment through extensive sensor networks and react accordingly to optimize resource consumption. In order to do this, the Smart Grids need to understand the existing relationship between energy demand and a set of relevant climatic variables. All smart “systems” (buildings, cities, homes, consumers, etc.) have the potential to employ their intelligence for self-adaptation to climate conditions. After introducing the Smart World, a global framework for the collaboration of these smart systems, this paper presents the relationship found at experimental level between a range of relevant weather variables and electric power demand patterns, presenting a case study using an agent-based system, and emphasizing the need to consider this relationship in certain Smart World (and specifically Smart Grid and microgrid) applications.

  20. Role of lunar atmospheric tides in thermosphere density

    NASA Astrophysics Data System (ADS)

    Palus, Shannon

    2014-11-01

    Half a million objects, including debris, satellites, and the International Space Station, orbit Earth in the thermosphere, the largest layer of the planet's atmosphere. To predict the orbits—and potential collisions—of all this stuff, scientists must forecast the weather in the thermosphere. To help develop a more comprehensive and nuanced model of this weather, Zhang et al. explored the role that lunar atmospheric tides play in the density of thermosphere air.

  1. Impact of synoptic weather patterns and inter-decadal climate variability on air quality in the North China Plain during 1980-2013

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Ding, Aijun; Mao, Huiting; Nie, Wei; Zhou, Derong; Liu, Lixia; Huang, Xin; Fu, Congbin

    2016-01-01

    Potential relationships between air quality, synoptic weather patterns, and the East Asian Monsoon (EAM) over the North China Plain (NCP) were examined during the time period of 1980-2013 using a weather typing technique and ground-based air pollution index (API) data from three cities: Beijing, Tianjin and Shijiazhuang. Using the Kirchhofer method, circulation patterns during the 34-yr study period were classified into 5 categories, which were further used to understand the quantitative relationship between weather and air quality in NCP. The highest API values were associated with a stagnant weather condition when wide-spread stable conditions controlled most part of NCP, while westerly and southerly wind flowed over the northern and eastern part of this region, resulting in both the regional transport and local build-up of air pollutants. Under the continuous control of this weather pattern, API values were found to increase at a rate of 8.5 per day on average. Based on the qualitative and quantitative analysis, a significant correlation was found between the strength of EAM and inter-annual variability of frequencies of the weather patterns. The strengthening of summer/winter monsoon could increase the frequency of occurrence of cyclone/anticyclone related weather patterns. Time series of climate-induced variability in API over the 34 years were reconstructed based on the quantitative relationship between API and predominant weather patterns during 2001-2010. Significant connections between EAM and reconstructed API were found on both the inter-annual and inter-decadal scales. In winter and summer, strengthening/weakening of EAM, which was generally associated with the change of the representative circulation patterns, could improve/worsen air quality in this region.

  2. Ocean tide energy converter

    SciTech Connect

    Rainey, D.E.

    1980-06-24

    A tide motor energy source includes a tidal piston with a valved chamber. The piston drives a hydraulic ram to generate electrical power through a pressure accumulator and hydraulic motor. The ram can be locked hydraulically to enable the tidal piston to be held fixed at a desired elevation and the valves in the chamber permit it to be filled with water or air. The piston with its chamber filled with air at its low tide position and then released for controlled ascent while submerged acts as a submerged float for driving the ram upwardly while the tide runs in during one phase of its operation. The piston with its chamber filled with water while locked at its highest position as the tide begins to run out, and then released to fall under control, acts as a weight suspended in air after the water level drops below the piston for driving the ram downwardly during the second phase of its operation. The rising and falling motion of the tidal piston is used as the energy source.

  3. Tides in Titan

    NASA Technical Reports Server (NTRS)

    Rappaport, Nicole J.

    1997-01-01

    Tides raised in Titan by Saturn give rise to a static and a periodic deformation; both will be measured with Doppler tracking during the CASSINI Tour of the Saturnian System. The latter deformation is due to the significant eccentricity of Titan's orbit and has a frequency equal to the orbital angular velocity of Titan.

  4. Observational Study on the Internal Tides in the Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Liang, H.; Tian, J.; Zhao, W.

    2015-12-01

    South China Sea (SCS) is the largest marginal sea of the western north Pacific. Due to the interaction between the abrupt topography at the Luzon Strait (LS) and the barotropical tides, internal tides (ITs) are active in the northern SCS. Therefore, to clarify the temporal variations and spatial distributions of the internal tides in the northern SCS, and to investigate the propagation and evolution of internal tides and its contributions to the deep ocean mixing, a mooring array with up to 11 moorings has been built in the northern SCS since 2010. Based on continuous observations for 5 years, a series of studies are conducted here, to analyze the temporal variability and spatial structure of the internal tides in the SCS, to describe the propagation paths of the internal tides in the SCS, to explore the influence of barotropical tides at LS to the internal tides in the northern SCS, and to quantify the contributions of the internal tides to deep ocean mixing in the northern SCS. A series of research results are as follows: In the northern SCS, the diurnal tide kinetic energy is found to exhibit apparent seasonal variability—strongest in summer and weakest in autumn and spring. However, the variability of semidiurnal tide is just opposite, but with smaller amplitude. It is further found that the barotropical tide and the diurnal internal tide observed at the generation site also display a similar seasonal variation with diurnal internal tides in northeast SCS, which indicates that the barotropical tidal current at the source region has the potential to account for the seasonal variability of the diurnal tide on the continental slope of the northern SCS. During the westward propagation from LS to the continental slope and shelf in the SCS, the energy proportion of higher mode internal waves are increasing for diurnal tide, but decreasing gradually for semidiurnal tide. The internal tides are propagating away from the Luzon Strait, with the diurnal internal tides

  5. Tides and deltaic morphodynamics

    NASA Astrophysics Data System (ADS)

    Plink-Bjorklund, Piret

    2016-04-01

    Tide-dominated and tide-influenced deltas are not widely recognized in the ancient record, despite the numerous modern and Holocene examples, including eight of the twelve modern largest deltas in the world, like the Ganges-Brahmaputra, Amazon, Chang Jiang, and Irrawadi. Furthermore, tide-dominated or tide-influenced deltas are suggested to be more common in inner-shelf or embayment settings rather than close to or at a shelf edge, primarily because wave energy is expected to be higher and tidal energy lower in outer shelf and shelf-edge areas. Thus, most shelf-edge deltas are suggested to be fluvial or wave dominated. However, there are ancient examples of tide-influenced shelf-edge deltas, indicating that the controls on tidal morphodynamics in deltas are not yet well understood. This paper asks the following questions: (1) How do tides influence delta deposition, beyond creating recognizable tidal facies? (2) Does tidal reworking create specific geometries in delta clinoforms? (3) Does tidal reworking change progradation rates of deltas? (4) Is significant tidal reworking of deltas restricted to inner-shelf deltas only? (5) What are the conditions at which deltas may be tidally influenced or tide-dominated in outer-shelf areas or at the shelf edge? (6) What are the main morphodynamic controls on the degree of tidal reworking of deltas? The paper utilizes a dataset of multiple ancient and modern deltas, situated both on the shelf and shelf edge. We show that beyond the commonly recognized shore-perpendicular morphological features and the recognizable tidal facies, the main effects of tidal reworking of deltas are associated with delta clinoform morphology, morphodynamics of delta lobe switching, delta front progradation rates, and the nature of the delta plain. Strong tidal influence is here documented to promote subaqueous, rapid progradation of deltas, by efficiently removing sediment from river mouth and thus reducing mouth bar aggradation and fluvial delta

  6. An objective daily Weather Type classification for Iberia since 1850; patterns, trends, variability and impact in precipitation

    NASA Astrophysics Data System (ADS)

    Ramos, A. M.; Trigo, R. M.; Lorenzo, M. N.; Vaquero, J. M.; Gallego, M. C.; Valente, M. A.; Gimeno, L.

    2009-04-01

    the winter precipitation amount, observed on a daily basis. On the other hand, the three wettest WTs, namely the Cyclonic (C), South-westerly (SW) and Westerly (W) types, together representing roughly a third of all winter days, do account for more than 60% of the observed daily precipitation. It is shown that the large inter-annual variability of precipitation in both cities is highly related with the corresponding inter-annual variability of the wet WTs. Ansell, T. J. et al. (2006) Daily mean sea level pressure reconstructions for the European - North Atlantic region for the period 1850-2003, Journal of Climate, 19, 2717-2742, doi: 10.1175/JCLI3775.1 Huth R., Beck C., Philipp A., Demuzere M, Ustrnul Z, Cahynová M., Kyselý J., Tveito O.E. (2008) Classifications of atmospheric circulation patterns: recent advances and applications. Trends and Directions in Climate Research: Ann. N.Y. Acad. Sci. 1146:, 105-152 Jones, P. D. , M. Hulme , K. R. Briffa. (1993) A comparison of Lamb circulation types with an objective classification scheme. Int. J. Climatol. 13: 655- 663. Lorenzo M.N., Taboada J.J. and Gimeno L. (2008) Links between circulation weather types and teleconnection patterns and their influence on precipitation patterns in Galicia (NW Spain). Int. J. Climatol. Published Online: Nov 12 2007 5:30AM DOI: 10.1002/joc.1646. Trigo R.M. and Da Camara C.C. (2000) Circulation weather types and their influence on the precipitation regime in Portugal. Int. J. Climatol., 20, 1559-1581.

  7. Integrating interannual climate variability forecasts into weather-indexed crop insurance. The case of Malawi, Kenya and Tanzania

    NASA Astrophysics Data System (ADS)

    Vicarelli, M.; Giannini, A.; Osgood, D.

    2009-12-01

    In this study we explore the potential for re-insurance schemes built on regional climatic forecasts. We focus on micro-insurance contracts indexed on precipitation in 9 villages in Kenya, Tanzania (Eastern Africa) and Malawi (Southern Africa), and analyze the precipitation patterns and payouts resulting from El Niño Southern Oscillation (ENSO). The inability to manage future climate risk represents a “poverty trap” for several African regions. Weather shocks can potentially destabilize not only household, but also entire countries. Governments in drought-prone countries, donors and relief agencies are becoming aware of the importance to develop an ex-ante risk management framework for weather risk. Joint efforts to develop innovative mechanisms to spread and pool risk such as microinsurance and microcredit are currently being designed in several developing countries. While ENSO is an important component in modulating the rainfall regime in tropical Africa, the micro-insurance experiments currently under development to address drought risk among smallholder farmers in this region do not take into account ENSO monitoring or forecasting yet. ENSO forecasts could be integrated in the contracts and reinsurance schemes could be designed at the continental scale taking advantage of the different impact of ENSO on different regions. ENSO is associated to a bipolar precipitation pattern in Southern and Eastern Africa. La Niña years (i.e. Cold ENSO Episodes) are characterized by dry climate in Eastern Africa and wet climate in Southern Africa. During El Niño (or Warm Episode) the precipitation dipole is inverted, and Eastern Africa experiences increased probability for above normal rainfall (Halpert and Ropelewski, 1992, Journal of Climate). Our study represents the first exercise in trying to include ENSO forecasts in micro weather index insurance contract design. We analyzed the contracts payouts with respect to climate variability. In particular (i) we simulated

  8. A complete spherical harmonic approach to luni-solar tides

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1989-01-01

    In this work a spherical harmonic theory of ocean tides is presented. The theory is based on Laplace tide equations modified to include turbulence with constant eddy viscosity, linearized bottom friction, and oceanic loading and self-gravitation. Variable bathymetry is also treated in harmonic terms, and no-flow boundary conditions are applied at continental coastlines. The tide and boundary constraint equations are reduced to matrix form and solved by a weighted least-squares procedure. Five zonal luni-solar tides, ranging in period from 14 days to 18.6 yr, are investigated using the theory; such tides have typically been difficult to compute using traditional numerical approaches. The polar motion and changes in the length of day induced by these long-period tides are calculated. Tidal solutions are compared extensively with results from other tidal theories and from recent satellite and sea-level observations. The greatest limitation to accurate prediction of zonal tides - for any theory - appears to be the marginal failure of all tide theories to conserve mass globally; the use of additional mass constraints may be warranted.

  9. SUITS/SWUSV: a small-size mission to address solar spectral variability, space weather and solar-climate relations

    NASA Astrophysics Data System (ADS)

    Damé, Luc; Keckhut, Philippe; Hauchecorne, Alain; Meftah, Mustapha; Bekki, Slimane

    2016-07-01

    We present the SUITS/SWUSV microsatellite mission investigation: "Solar Ultraviolet Influence on Troposphere/Stratosphere, a Space Weather & Ultraviolet Solar Variability" mission. SUITS/SWUSV was developed to determine the origins of the Sun's activity, understand the flaring process (high energy flare characterization) and onset of CMEs (forecasting). Another major objective is to determine the dynamics and coupling of Earth's atmosphere and its response to solar variability (in particular UV) and terrestrial inputs. It therefore includes the prediction and detection of major eruptions and coronal mass ejections (Lyman-Alpha and Herzberg continuum imaging) the solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance measures from 170 to 400 nm). The mission is proposed on a sun-synchronous polar orbit 18h-6h (for almost constant observing) and proposes a 7 instruments model payload of 65 kg - 65 W with: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200-220 nm Herzberg continuum) imaging (sources of variability); SOLSIM (Solar Spectral Irradiance Monitor), a spectrometer with 0.65 nm spectral resolution from 170 to 340 nm; SUPR (Solar Ultraviolet Passband Radiometers), with UV filter radiometers at Lyman-Alpha, Herzberg, MgII index, CN bandhead and UV bands coverage up to 400 nm; HEBS (High Energy Burst Spectrometers), a large energy coverage (a few tens of keV to a few hundreds of MeV) instrument to characterize large flares; EPT-HET (Electron-Proton Telescope - High Energy Telescope), measuring electrons, protons, and heavy ions over a large energy range; ERBO (Earth Radiative Budget and Ozone) NADIR oriented; and a vector magnetometer. Complete accommodation of the payload has been performed on a PROBA type platform very nicely. Heritage is important both for instruments (SODISM and PREMOS on PICARD, LYRA on PROBA-2, SOLSPEC on ISS

  10. Altimetry, Orbits and Tides

    NASA Technical Reports Server (NTRS)

    Colombo, O. L.

    1984-01-01

    The nature of the orbit error and its effect on the sea surface heights calculated with satellite altimetry are explained. The elementary concepts of celestial mechanics required to follow a general discussion of the problem are included. Consideration of errors in the orbits of satellites with precisely repeating ground tracks (SEASAT, TOPEX, ERS-1, POSEIDON, amongst past and future altimeter satellites) are detailed. The theoretical conclusions are illustrated with the numerical results of computer simulations. The nature of the errors in this type of orbits is such that this error can be filtered out by using height differences along repeating (overlapping) passes. This makes them particularly valuable for the study and monitoring of changes in the sea surface, such as tides. Elements of tidal theory, showing how these principles can be combined with those pertinent to the orbit error to make direct maps of the tides using altimetry are presented.

  11. Astronomical tides and earthquakes

    NASA Astrophysics Data System (ADS)

    Wu, Xiaoping; Mao, Wei; Huang, Yong

    2001-03-01

    A review on the studies of correlation between astronomical tides and earthquakes is given in three categories, including (1) earthquakes and the relative locations of the sun, the moon and the earth, (2) earthquakes and the periods and phases of tides and (3) earthquakes and the tidal stress. The first two categories mainly investigate whether or not there exist any dominant pattern of the relative locations of the sun, the moon and the earth during earthquakes, whether or not the occurrences of earthquakes are clustered in any special phase during a tidal period, whether or not there exists any tidal periodic phenomenon in seismic activities, By empasizing the tidal stress in seismic focus, the third category investigates the relationship between various seismic faults and the triggering effects of tidal stress, which reaches the crux of the issue. Possible reasons to various inconsistent investigation results by using various methods and samples are analyzed and further investigations are proposed.

  12. The USDA Southern Plains Climate Hub: Regional agricultural management in the context of weather and climate variability and change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Southern Great Plains of the United States, extremes of weather and climate are the norm. Farmers, ranchers, and foresters rely upon timely and authoritative data and information when making management decisions that are weather- and climate-dependent. In response to the needs of these agricu...

  13. Deep sea tides determination from GEOS-3

    NASA Technical Reports Server (NTRS)

    Maul, G. A.; Yanaway, A.

    1978-01-01

    GEOS 3 altimeter data in a 5 degree X 5 degree square centered at 30 deg N, 70 deg W were analyzed to evaluate deep sea tide determination from a spacecraft. The signal to noise ratio of known tidal variability to altimeter measurement of sea level above the ellipsoid was 0.1. A sample was obtained in a 5 deg x 5 deg area approximately once every four days. The randomly spaced time series was analyzed using two independent least squares techniques.

  14. Tides of the Caribbean Sea

    SciTech Connect

    Kjerfve, B.

    1981-05-20

    Analysis of tidal characteristics from 45 gauge locations indicates that the Caribbean Sea has a microtidal range, for the most part between 10 and 20 cm. The tide is primarily either mixed semidiurnal or mixed diurnal but a substantial section from Puerto Rico to Venezuela experiences diurnal tides. Empirical charts of six component tides (M/sub 2/, S/sub 2/, N/sub 2/, K/sub 1/, O/sub 1/, and P/sub 1/) show local detail of phase and amplitude. Each of the semidiurnal component tides is characterized by anticlockwise rotating amphidromes centered in the eastern Caribbean. There is evidence of strong radiational forcing of the S/sub 2/ tide in the south-western Caribbean. The diurnal component tides are largely uniform in both phase and amplitude for most of the western and central Caribbean. However, the diurnal phases increase rapidly towards the northwest and the Yucatan Channel.

  15. A Fourier series model to predict hourly heating and cooling energy use in commercial buildings with outdoor temperature as the only weather variable

    SciTech Connect

    Dhar, A.; Reddy, T.A.; Claridge, D.E.

    1999-02-01

    Accurate modeling of hourly heating and cooling energy use in commercial buildings can be achieved by a Generalized Fourier Series (GFS) approach involving weather variables such as dry-bulb temperature, specific humidity and horizontal solar flux. However, there are situations when only temperature data is available. The objective of this paper is to (i) describe development of a variant of the GFS approach which allows modeling both heating and cooling hourly energy use in commercial buildings with outdoor temperature as the only weather variable and (ii) illustrate its application with monitored hourly data from several buildings in Texas. It is found that the new Temperature based Fourier Series (TFS) approach (1) provides better approximation to heating energy use than the existing GFS approach, (ii) can indirectly account for humidity and solar effects in the cooling energy use, (iii) offers physical insight into the operating pattern of a building HVAC system and (iv) can be used for diagnostic purposes.

  16. Using airborne LIDAR to measure tides and river slope

    NASA Astrophysics Data System (ADS)

    Talke, S. A.; Hudson, A.; Chickadel, C. C.; Farquharson, G.; Jessup, A. T.

    2014-12-01

    The spatial variability of tides and the tidally-averaged water-level is often poorly resolved in shallow waters, despite its importance in validating models and interpreting dynamics. In this contribution we explore using airborne LIDAR to remotely observe tides and along-river slope in the Columbia River estuary (CRE). Using an airplane equipped with LIDAR, differential GPS, and an infra-red camera, we flew 8 longitudinal transects over a 50km stretch of the CRE over a 14 hour period in June 2013. After correcting for airplane elevation, pitch and roll and median filtering over 1km blocks, a spatially-resolved data set of relative water level was generated. Results show the tide (amplitude 2m) propagating upstream at the expected phase velocity. A sinusoid with 2 periods (12.4 and 24 hours) was next fit to data to produce a smooth tide and extract the mean slope. Comparison with 4 tide gauges indicates first order agreement with measured tides (rms error 0.1m), and confirms that a substantial sub-tidal gradient exists in the CRE. This proof-of-concept experiment indicates that remote sensing of tides in coastal areas is feasible, with possible applications such as improving bathymetric surveys or inferring water depths.

  17. Temporal and spatial variability of Fe and Mn in perched groundwater flowing through weathered argillite underlying a steep forested hillslope

    NASA Astrophysics Data System (ADS)

    Kim, H.; Bishop, J. K.

    2013-12-01

    Groundwater flowing through weathered bedrock dictates the runoff chemistry to streams in many catchments yet; its chemical evolution has been rarely documented. In particular, observations of Fe and Mn dynamics in groundwater are extremely challenging due to their high reactivity. To preserve the sample integrity for these elements we have developed a new sampling scheme that is applicable to autosamplers; a gravitational filtration system (GFS). GFS is capable of filtering samples by gravity within 30 minutes after the sampling. The GFS samples showed a good agreement with reference samples, which were collected following the standard sampling method for trace metals (i.e. immediate filtration and acidification). Since October 2011, GFS has been employed to monitor Fe and Mn in perched groundwater that moves through weathered argillite in an intensively instrumented hillslope (Rivendell), in the Angelo Coast Range Reserve. The study site is located at the headwaters of the Eel River, northern California, characterized by a typical coastal Californian Mediterranean climate. We collected groundwater samples at 3 wells along the hillslope (upslope (W10), mid-slope (W3) and near the creek (W1)) with 1-3 day intervals. Additionally, rainwater and throughfall samples were collected at a meadow near the hillslope and at the middle of the hillslope, respectively. The results from our observations indicate that Fe and Mn exhibit distinct spatial and temporal behavior under variable hydrologic conditions. The concentrations of Fe in throughfall vs. rainwater were similar (0.45μM vs. 0.49μM), but Mn in throughfall was 10-fold higher than that in rainwater (1.2 μM vs. 0.1 μM). In the early rainy season, W10's water table was deep (-18m) and Fe and Mn in W10 were 30-150 nM and 1-2 μM, respectively. As the rainy season proceeds, W10's water table rose by 4-6m, indicating the arrival of new water. At this time, Mn in W10 decreased to ~0.1 μM, synchronizing with the water

  18. The ultimate high tide

    SciTech Connect

    Dean, R.G. )

    1990-01-01

    This paper discusses the possible coastal impacts of a rise in sea level. Control measures that are available to coastal communities are emphasized, including pumping of seawater into the ground, replenishing beach sand, protection or moving of potable-water intakes, elevating roadways, and building dikes. Economics will determine which, if any, measures are reasonable at a particular site. There is an upward trend in the mean CO{sub 2} concentration and predictions about the greenhouse effect are creating a rising tide of concern.

  19. Tide gate valve

    SciTech Connect

    Raftis, S. G.

    1985-01-08

    A tide gate check valve in which at least three converging sides are provided at a tapered region of a flexible sleeve, so that on reverse back pressure build-up of fluid, reverse fluid flow is prevented, while the valve sleeve does not invert or collapse. The present configuration features embedded reinforcing elements for resisting inversion or collapsing when the back pressure builds up. This feature is especially important for large-sized conduits of 36'' or 72'' diameter, or even larger, such as are common in storm sewer applications.

  20. SWUSV: a microsatellite mission for space weather early forecasting of major flares and CMEs and the complete monitoring of the ultraviolet solar variability influence on climate

    NASA Astrophysics Data System (ADS)

    Damé, Luc

    The SWUSV (Space Weather & Ultraviolet Solar Variability) proposed microsatellite mission encompasses three major scientific objectives: (1) Space Weather including the prediction and detection of major eruptions and coronal mass ejections (using Lyman-Alpha and Herzberg continuum imaging and H-Alpha ground support); (2) solar forcing on the climate through radiation and their interactions with the local stratosphere (UV spectral irradiance from 180 to 400 nm by bands of 10 to 20 nm, including ozone, plus Lyman-Alpha and the CN bandhead); (3) simultaneous local radiative budget of the Earth, UV to IR, with an accuracy better than 1% in differential. The mission is on a sun-synchronous polar orbit and proposes 5 instruments to the model payload: SUAVE (Solar Ultraviolet Advanced Variability Experiment), an optimized telescope for FUV (Lyman-Alpha) and MUV (200-220 nm Herzberg continuum) imaging (sources of variability); UPR (Ultraviolet Passband Radiometers), with 64 UV filter radiometers; a vector magnetometer; thermal plasma measurements and Langmuir probes; and a total and spectral solar irradiance and Earth radiative budget ensemble (SERB, Solar irradiance & Earth Radiative Budget). SWUSV is proposed as a small mission to CNES and to ESA for a possible flight as early as 2020-2021. With opening to Chinese collaboration (ESA-CAS Small Mission) a further instrument could be added (HEBS, High Energy Burst Spectrometers) to reinforced Space Weather flares prediction objectives.

  1. Spectral variability on primitive asteroids of the Themis and Beagle families: Space weathering effects or parent body heterogeneity?

    NASA Astrophysics Data System (ADS)

    Fornasier, S.; Lantz, C.; Perna, D.; Campins, H.; Barucci, M. A.; Nesvorny, D.

    2016-05-01

    Themis is an old and statistically robust asteroid family populating the outer main belt, and resulting from a catastrophic collision that took place 2.5 ± 1.0 Gyr ago. Within the old Themis family a young sub-family, Beagle, formed less than 10 Myr ago, has been identified. We present the results of a spectroscopic survey in the visible and near infrared range of 22 Themis and 8 Beagle families members. The Themis members investigated exhibit a wide range of spectral behaviors, including asteroids with blue/neutral and moderately red spectra, while the younger Beagle family members look spectrally bluer than the Themis ones and they have a much smaller spectral slope variability. Four Themis members, including (24) Themis, have absorption bands centered at 0.68-0.73 μm indicating the presence of aqueously altered minerals. The best meteorite spectral analogues found for both Themis and Beagle families members are carbonaceous chondrites having experienced different degrees of aqueous alteration, prevalently CM2 but also CV3 and CI, and some of them are chondrite samples being unusual or heated. The presence of aqueous altered materials on the asteroids surfaces and the meteorite matches indicate that the parent body of the Themis family experienced mild thermal metamorphism in the past. We extended the spectral analysis including the data available in the literature on Themis and Beagle families members, and we looked for correlations between spectral behavior and physical parameters using the albedo and size values derived from the WISE data. The analysis of this larger sample confirms the spectral diversity within the Themis family and that Beagle members tend to be bluer and to have an higher albedo. The differences between the two families may be partially explained by space weathering processes, which act on these primitive surfaces in a similar way than on S-type asteroids, i.e. producing reddening and darkening. However we see several Themis members

  2. Europa Tide Movie

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for Europa Tide Movie

    In this movie Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole moon, and being far from the sun, the ocean surface is globally frozen over. Europa's orbit is eccentric, which means as it travels around Jupiter, large tides, raised by Jupiter, rise and fall. Jupiter's position relative to Europa is also seen to librate, or wobble, with the same period. This tidal kneading causes frictional heating within Europa, much in the same way a paper clip bent back and forth can get hot to the touch, as illustrated by the red glow in the interior of Europa's rocky mantle and in the lower, warmer part of its ice shell. This tidal heating is what keeps Europa's ocean liquid and could prove critical to the survival of simple organisms within the ocean, if they exist.

  3. Tides of the British Seas

    ERIC Educational Resources Information Center

    Sandon, Frank

    1975-01-01

    Examines the gravitational effects and the way that local conditions interact with these effects to produce the tides characteristic of the British seas. Presents some effects of tides including the possibility of harnessing tidal energy and the effect of tidal friction on the use of the earth as a clock. (GS)

  4. Relative sea level trend and variability in the central Mediterranean in the time span 1872-2014 from tide gauge data: implications for future projections

    NASA Astrophysics Data System (ADS)

    Anzidei, Marco; Vecchio, Antonio

    2015-04-01

    We used tidal data collected in the time span 1872-2014 from a set of historical and modern stations located in the central Mediterranean, along the coasts of Italy, France, Slovenia and Croatia. The longest records span across the last two or three centuries for the tidal stations of Genova, Marseille, Trieste and Venice. While data from Bakar, Dubrovink, Rovinji and Split, all located along the coast of the Adriatic sea, provide valid records for a time span about 50 years long. In addition to these stations, since 1998 become available for the Italian region new sea level data from the dense national tidal network (www.mareografico.it). These digital stations are collecting data continuously at 10 minute sampling interval with a nominal accuracy at 1 mm. Therefore, in addition to the historical stations, we have the opportunity to analyze a sea level data set that cover about the last 16 years. In this study we show and discuss the results of our analysis of sea level data for the central Mediterranean, providing new insights on sea level trend and variability for about the past 140 years. Finally, based on sea level data and IPCC reports, we provide future sea level projections for this region for the year 2100 with implications for coastal flooding of lowland areas.

  5. Population dynamics of red tide dinoflagellates

    NASA Astrophysics Data System (ADS)

    Wyatt, Timothy; Zingone, Adriana

    2014-03-01

    Sea-surface discolorations due to high concentrations of phytoplankton are called red tides. Their ecological significance is a long standing puzzle, and they are sometimes considered pathological. Here we propose that many red tides, particularly but not exclusively those composed of certain autotrophic dinoflagellates, are presexual/sexual swarms, essential links in their complex life cycles. This view provides a rationale for the appearance of these organisms in thin surface layers, and helps explain their ephemeral nature. We suggest that further understanding of this phenomenon, and of phytoplankton ecology in general, would benefit from attention to the 'net reproductive value‧ (r) over the whole life cycle as well as to the division rate (μ) of the vegetative phase. It is argued that r is strategically adapted to seasonal cycles and long term environmental variability, while μ reflects tactical needs (timing) and constraints (grazers, parasites) on vegetative growth.

  6. Tides in the Martian Atmosphere as Observed by MAVEN IUVS

    NASA Astrophysics Data System (ADS)

    Lo, D.; Yelle, R. V.; Schneider, N. M.; Jain, S.; Stewart, I. F.; England, S.; Deighan, J.; Stiepen, A.; Evans, J. S.; Stevens, M. H.; Chaffin, M.; Crismani, M. M. J.; McClintock, W. E.; Clarke, J. T.; Holsclaw, G. M.; Lefèvre, F.; Jakosky, B. M.

    2015-12-01

    Driven by the diurnal solar heating, atmospheric tides are global scale oscillations in density, pressure and temperature. They are responsible for a large fraction of the variability of the atmosphere and the circulation and transport processes that stem from this variability. Here we present first observations of tides in the Martian atmosphere from the Mars Atmospheric and Volatile EvolutioN Mission (MAVEN) Imaging UltraViolet Spectrograph (IUVS). CO2+ (B2Σ+→X2Π) UV doublet emission intensities are isolated from limb profiles over the 100-190 km altitude range using a multiple linear regression procedure, and CO2 densities are then obtained by fitting a Chapman layer. Variations of the CO2 density exhibit significant persistent structure with longitudinal wavenumbers 1, 2 and 3 in a fixed local solar time frame, and such a structure points to non-migrating tides. Specific tidal modes are identified through analysis of the amplitudes and phases of the various wavenumber components and their variation with latitude. The wave-2 component is dominated by the diurnal eastward-moving DE1 tide at the equator and the diurnal stationary D0 tide at the midlatitudes. Wave-3 is dominated by the diurnal eastward-moving DE2 tide, with an unknown tide becoming dominant north of 30°N. Structure in the wave-1 component can be explained by the semidiurnal westward-moving SW1 tide. Our observations are consistent with past observations by Mars Express SPectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) [Withers et al., 2011], Mars Global Surveyor (MGS) aerobraking data [Withers et al., 2003; Moudden and Forbes, 2008] and MGS electron density measurements [Cahoy et al., 2007].

  7. On the sub-grid-scale variability of oceanic winds and the accuracy of numerical weather prediction models as deduced from QuikSCAT backscatter distributions

    NASA Astrophysics Data System (ADS)

    Suzuki, Naoya; Donelan, Mark A.; Plant, William J.

    2007-04-01

    Observed probability distributions of QuikSCAT scatterometer cross sections are matched to expected distributions calculated using a Geophysical Model Function (GMF) with a wind speed threshold and inherent wind variability on the subfootprint scale and also on grid scales of numerical weather prediction (NWP) models. Two independent approaches are taken: In one, the 3-D sample size is 2° × 2° and 1 day, and the wind speed is assumed to be Rayleigh distributed while directions relative to QuickSCAT antenna directions are assumed to be uniform; in the other, the data are binned by NWP analyzed wind speeds into 1 m/s bins and sample sizes of the grid area of the NWP models. Using the results, the variability on these scales is mapped as a function of wind speed, latitude, and season in an effort to establish a global climatology of wind-speed variability. On the basis of the stable calibration of QuikSCAT, the bias of surface winds produced by the National Center for Environmental Prediction (NCEP) and the European Center for Medium-Range Weather Forecasts (ECMWF) is shown to be substantial and strongly dependent on wind speed, latitude, and season. Changes in wind-speed variability with changes in averaging scale are further explored and estimates of the kinetic energy spectra of the mesoscale to basin-scale winds are determined.

  8. Fundamental statistical relationships between monthly and daily meteorological variables: Temporal downscaling of weather based on a global observational dataset

    NASA Astrophysics Data System (ADS)

    Sommer, Philipp; Kaplan, Jed

    2016-04-01

    Accurate modelling of large-scale vegetation dynamics, hydrology, and other environmental processes requires meteorological forcing on daily timescales. While meteorological data with high temporal resolution is becoming increasingly available, simulations for the future or distant past are limited by lack of data and poor performance of climate models, e.g., in simulating daily precipitation. To overcome these limitations, we may temporally downscale monthly summary data to a daily time step using a weather generator. Parameterization of such statistical models has traditionally been based on a limited number of observations. Recent developments in the archiving, distribution, and analysis of "big data" datasets provide new opportunities for the parameterization of a temporal downscaling model that is applicable over a wide range of climates. Here we parameterize a WGEN-type weather generator using more than 50 million individual daily meteorological observations, from over 10'000 stations covering all continents, based on the Global Historical Climatology Network (GHCN) and Synoptic Cloud Reports (EECRA) databases. Using the resulting "universal" parameterization and driven by monthly summaries, we downscale mean temperature (minimum and maximum), cloud cover, and total precipitation, to daily estimates. We apply a hybrid gamma-generalized Pareto distribution to calculate daily precipitation amounts, which overcomes much of the inability of earlier weather generators to simulate high amounts of daily precipitation. Our globally parameterized weather generator has numerous applications, including vegetation and crop modelling for paleoenvironmental studies.

  9. How Can Conventional Drinking Water Treatment Facilities Build Resilience to Climate and Weather Induced Water Supply Variability?

    EPA Science Inventory

    Abstract: Water supplies are vulnerable to a host of climate- and weather-related stressors such as droughts, intense storms/flooding, snowpack depletion, sea level changes, and consequences from fires, landslides, and excessive heat or cold. Surface water resources (lakes, reser...

  10. Lunar Core and Tides

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

    2004-01-01

    Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacements. Past solutions using the LLR data have given results for dissipation due to solid-body tides and fluid core [1] plus Love number [1-5]. Detection of CMB flattening, which in the past has been marginal but improving [3,4,5], now seems significant. Direct detection of the core moment has not yet been achieved.

  11. Electrodynamics of ionospheric weather over low latitudes

    NASA Astrophysics Data System (ADS)

    Abdu, Mangalathayil Ali

    2016-12-01

    The dynamic state of the ionosphere at low latitudes is largely controlled by electric fields originating from dynamo actions by atmospheric waves propagating from below and the solar wind-magnetosphere interaction from above. These electric fields cause structuring of the ionosphere in wide ranging spatial and temporal scales that impact on space-based communication and navigation systems constituting an important segment of our technology-based day-to-day lives. The largest of the ionosphere structures, the equatorial ionization anomaly, with global maximum of plasma densities can cause propagation delays on the GNSS signals. The sunset electrodynamics is responsible for the generation of plasma bubble wide spectrum irregularities that can cause scintillation or even disruptions of satellite communication/navigation signals. Driven basically by upward propagating tides, these electric fields can suffer significant modulations from perturbation winds due to gravity waves, planetary/Kelvin waves, and non-migrating tides, as recent observational and modeling results have demonstrated. The changing state of the plasma distribution arising from these highly variable electric fields constitutes an important component of the ionospheric weather disturbances. Another, often dominating, component arises from solar disturbances when coronal mass ejection (CME) interaction with the earth's magnetosphere results in energy transport to low latitudes in the form of storm time prompt penetration electric fields and thermospheric disturbance winds. As a result, drastic modifications can occur in the form of layer restructuring (Es-, F3 layers etc.), large total electron content (TEC) enhancements, equatorial ionization anomaly (EIA) latitudinal expansion/contraction, anomalous polarization electric fields/vertical drifts, enhanced growth/suppression of plasma structuring, etc. A brief review of our current understanding of the ionospheric weather variations and the

  12. M2 world ocean tide from tide gauge measurements

    SciTech Connect

    Francis, O.; Mazzega, P. )

    1991-06-01

    An empirical model of the M2 oceanic tide has been computed form the harmonic constants of a subset of deep sea and coastal tide gauge measurements. The optimal interpolation of these data based on inverse theory' uses a priori covariance functions deduced from a global hydrodynamical model. The inverse solution, produced with its associated error maps and samples of error spectra, is surprisingly good when compared to in situ data and to a hydrodynamical model.

  13. M2 World Ocean tide from tide gauge measurements

    NASA Astrophysics Data System (ADS)

    Francis, O.; Mazzega, P.

    An empirical model of the M2 oceanic tide has been computed from the harmonic constants of a subset of deep sea and coastal tide gauge measurements. The optimal interpolation of these data based on “inverse theory” uses a priori covariance functions deduced from a global hydrodynamical model. The inverse solution, produced with its associated error maps and samples of error spectra, is surprisingly good when compared to in situ data and to a hydrodynamical model.

  14. Perigean Spring Tides and Apogean Neap Tides in History

    NASA Astrophysics Data System (ADS)

    Olson, Donald W.

    2012-01-01

    On January 4, 1912 - almost exactly 100 years ago - both a full Moon and a lunar perigee occurred, with these two events separated by only a few minutes of time and with the Earth near perihelion. The resulting lunar distance (356,375 km) on that date stands as the closest approach of the Moon to the Earth in an interval of more than 1400 years. The centennial of this extreme lunar perigee is an appropriate time to consider the effect of lunar distance on the range of ocean tides. At most ocean ports, spring tides of increased range occur near new and full Moon. If a lunar perigee falls near new or full Moon, then perigean spring tides of even greater range are possible. Conversely, if a lunar apogee falls near first quarter or last quarter Moon, then apogean neap tides of unusually reduced range can occur. Examples of perigean spring tides include a near-coincidence of lunar perigee and new Moon in December 1340 that may be related to a plot device in Chaucer's "The Franklin's Tale,” a Canterbury tale that describes an extreme high tide covering the rocks on the coast of Brittany in "the cold and frosty season of December.” Another example, the disaster known as the Bristol Channel Flood, occurred shortly after a lunar perigee and new Moon in January 1607. A German U-boat employed an exceptionally high perigean spring tide shortly after the new Moon of October 1939 to enter Scapa Flow by an unexpected route and sink the HMS Royal Oak. An apogean neap tide prevailed during the amphibious assault of the U. S. Marines at Tarawa in November 1943, making the eventual victory more costly because the landing craft were unable to reach the island and instead grounded on the surrounding reef.

  15. A threshold analysis of dengue transmission in terms of weather variables and imported dengue cases in Australia

    PubMed Central

    Huang, Xiaodong; Clements, Archie CA; Williams, Gail; Milinovich, Gabriel; Hu, Wenbiao

    2013-01-01

    Dengue virus (DENV) transmission in Australia is driven by weather factors and imported dengue fever (DF) cases. However, uncertainty remains regarding the threshold effects of high-order interactions among weather factors and imported DF cases and the impact of these factors on autochthonous DF. A time-series regression tree model was used to assess the threshold effects of natural temporal variations of weekly weather factors and weekly imported DF cases in relation to incidence of weekly autochthonous DF from 1 January 2000 to 31 December 2009 in Townsville and Cairns, Australia. In Cairns, mean weekly autochthonous DF incidence increased 16.3-fold when the 3-week lagged moving average maximum temperature was <32 °C, the 4-week lagged moving average minimum temperature was ≥24 °C and the sum of imported DF cases in the previous 2 weeks was >0. When the 3-week lagged moving average maximum temperature was ≥32 °C and the other two conditions mentioned above remained the same, mean weekly autochthonous DF incidence only increased 4.6-fold. In Townsville, the mean weekly incidence of autochthonous DF increased 10-fold when 3-week lagged moving average rainfall was ≥27 mm, but it only increased 1.8-fold when rainfall was <27 mm during January to June. Thus, we found different responses of autochthonous DF incidence to weather factors and imported DF cases in Townsville and Cairns. Imported DF cases may also trigger and enhance local outbreaks under favorable climate conditions. PMID:26038449

  16. Tides in Giant Planets

    NASA Astrophysics Data System (ADS)

    Stevenson, David J.

    2015-11-01

    The arrival of Juno at Jupiter in less than a year necessitates analysis of what we can learn from the gravitational signal due to tides raised on the planet by satellites (especially Io but also Europa). In the existing literature, there is extensive work on static tidal theory (the response of the planet to a tidal potential whose time dependence is ignored) and this is what is usually quoted when people refer to tidal Love numbers. If this were correct then there would be almost no new information content in the measurement of tidally induced gravity field, since the perturbation is of the same kind as the response to rotation (i.e., the measurement of J2, a well-known quantity). However, tides are dynamic (that is, k2 is frequency dependent) and so there is new information in the frequency dependent part. There is also (highly important) information in the imaginary part (more commonly expressed as tidal Q) but there is no prospect of direct detection of this by Juno since that quadrature signal is so small. The difference between what we expect to measure and what we can already calculate directly from J2 is easily shown to be of order the square of tidal frequency over the lowest order normal mode frequency, and thus of order 10%. However, the governing equations are not simple (not separable) because of the Coriolis force. An approximate solution has been obtained for the n =1 polytrope showing that the correction to k2 is even smaller, typically a few percent, because the tidal frequency is not very different from twice the rotation frequency. Moreover, it is not highly sensitive to structure in standard models. However, the deep interior of the planet may be stably stratified because of a compositional gradient and this modifies the tidal flow amplitude, changing the dynamic k2 but not the static k2. This raises the exciting possibility that we can use the determination of k2 to set bounds on the extent of static stability, if any. There is also the slight

  17. Weather Watch

    ERIC Educational Resources Information Center

    Bratt, Herschell Marvin

    1973-01-01

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

  18. Tides and Modern Geodesy

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Chao, Benjamin F. (Technical Monitor)

    2002-01-01

    In modem high-precision geodesy, and especially in modem space geodesy, every measurement that one makes contains tidal signals. Generally these signals are considered noise and must somehow be eliminated. The stringent requirements of the latest space geodetic missions place severe demands on tidal models. On the other hand, these missions provide the strongest data for improving tidal models. In particular, TOPEX/POSEIDON altimetry and LAGEOS laser ranging have improved models to such an extent that new geophysical information about the ocean and the solid Earth are coming to light. Presumably GRACE intersatellite ranging data will also add to this information. This paper discusses several of these new geophysical results, with special emphasis given to the dissipation of tidal energy. Strong constraints have recently been placed on the partitioning of energy dissipation among the ocean, atmosphere, and solid earth and between the deep and shallow ocean. The dissipation in deep water is associated with internal tides and has potentially important implications for understanding the ocean's thermohaline circulation.

  19. Tides in Colliding Galaxies

    NASA Astrophysics Data System (ADS)

    Duc, Pierre-Alain; Renaud, Florent

    Long tails and streams of stars are the most noticeable traces of galaxy collisions. However, their tidal origin was recognized only less than 50 years ago and more than 10 years after their first observations. This review describes how the idea of galactic tides has emerged thanks to advances in numerical simulations, from the first simulations that included tens of particles to the most sophisticated ones with tens of millions of them and state-of-the-art hydrodynamical prescriptions. Theoretical aspects pertaining to the formation of tidal tails are then presented. The third part turns to observations and underlines the need for collecting deep multi-wavelength data to tackle the variety of physical processes exhibited by collisional debris. Tidal tails are not just stellar structures, but turn out to contain all the components usually found in galactic disks, in particular atomic/molecular gas and dust. They host star-forming complexes and are able to form star-clusters or even second-generation dwarf galaxies. The final part of the review discusses what tidal tails can tell us (or not) about the structure and the content of present-day galaxies, including their dark components, and explains how they may be used to probe the past evolution of galaxies and the history of their mass assembly. On-going deep wide-field surveys disclose many new low-surface brightness structures in the nearby Universe, offering great opportunities for attempting galactic archeology with tidal tails.

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

    NASA Astrophysics Data System (ADS)

    Cassou, Christophe; Minvielle, Marie; Terray, Laurent; Périgaud, Claire

    2011-01-01

    The links between the observed variability of the surface ocean variables estimated from reanalysis and the overlying atmosphere decomposed in classes of large-scale atmospheric circulation via clustering are investigated over the Atlantic from 1958 to 2002. Daily 500 hPa geopotential height and 1,000 hPa wind anomaly maps are classified following a weather-typing approach to describe the North Atlantic and tropical Atlantic atmospheric dynamics, respectively. The algorithm yields patterns that correspond in the extratropics to the well-known North Atlantic-Europe weather regimes (NAE-WR) accounting for the barotropic dynamics, and in the tropics to wind classes (T-WC) representing the alteration of the trades. 10-m wind and 2-m temperature (T2) anomaly composites derived from regime/wind class occurrence are indicative of strong relationships between daily large-scale atmospheric circulation and ocean surface over the entire Atlantic basin. High temporal correlation values are obtained basin-wide at low frequency between the observed fields and their reconstruction by multiple linear regressions with the frequencies of occurrence of both NAE-WR and T-WC used as sole predictors. Additional multiple linear regressions also emphasize the importance of accounting for the strength of the daily anomalous atmospheric circulation estimated by the combined distances to all regimes centroids in order to reproduce the daily to interannual variability of the Atlantic ocean. We show that for most of the North Atlantic basin the occurrence of NAE-WR generally sets the sign of the ocean surface anomaly for a given day, and that the inter-regime distances are valuable predictors for the magnitude of that anomaly. Finally, we provide evidence that a large fraction of the low-frequency trends in the Atlantic observed at the surface over the last 50 years can be traced back, except for T2, to changes in occurrence of tropical and extratropical weather classes. All together, our

  1. Red Tide off Texas Coast

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Red tides (algae) bloomed late this summer along a 300-mile stretch of Texas' Gulf Coast, killing millions of fish and shellfish as well as making some people sick. State officials are calling this the worst red tide bloom in 14 years. The algae produces a poison that paralyzes fish and prevents them from breathing. There is concern that the deadly algae could impact or even wipe out this year's oyster harvest in Texas, which usually peaks during the Thanksgiving and Christmas holidays. The red tides were first observed off the Texas coast in mid-August and have been growing steadily in size ever since. Red tides tend to bloom and subside rapidly, depending upon changes in wind speed and direction, water temperature, salinity, and rainfall patterns (as the algae doesn't do as well in fresher water). This true-color image of the Texas Gulf Coast was acquired on September 29, 2000, by the Moderate-resolution Imaging Spectroradiometer (MODIS) flying aboard NASA's Terra spacecraft. The red tide can be seen as the dark reddish discoloration in the ocean running southwest to northeast along the coast. In this scene, the bloom appears to be concentrated north and east of Corpus Christi, just off Matagorda Island. The image was made at 500-meter resolution using a combination of MODIS' visible bands 1 (red), 4 (green), and 3 (blue). The city of Houston can be seen clearly as the large, greyish cluster of pixels to the north and west of Galveston Bay, which is about mid-way up the coastline in this image. Also visible in this image are plumes of smoke, perhaps wildfires, both to the north and northeast of Houston. For more information about red tides, refer to the Texas Red Tide Web site. Image courtesy Andrey Savtchenko, MODIS Data Support Team, and the MODIS Ocean Team, NASA's Goddard Space Flight Center

  2. Severe Weather

    ERIC Educational Resources Information Center

    Forde, Evan B.

    2004-01-01

    Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This article deals with a poster entitled, "Severe Weather," that has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in…

  3. Severe Weather

    ERIC Educational Resources Information Center

    Forde, Evan B.

    2004-01-01

    Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This month's insert, Severe Weather, has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in this poster are hurricanes,…

  4. Solar weather/climate predictions

    NASA Technical Reports Server (NTRS)

    Schatten, K. H.; Goldberg, R. A.; Mitchell, J. M.; Olson, R.; Schaefer, J.; Silverman, S.; Wilcox, J.; Williams, G.

    1979-01-01

    Solar variability influences upon terrestrial weather and climate are addressed. Both the positive and negative findings are included and specific predictions, areas of further study, and recommendations listed.

  5. Statistical selection of tide gauges for Arctic sea-level reconstruction

    NASA Astrophysics Data System (ADS)

    Svendsen, Peter Limkilde; Andersen, Ole Baltazar; Nielsen, Allan Aasbjerg

    2015-05-01

    In this paper, we seek an appropriate selection of tide gauges for Arctic Ocean sea-level reconstruction based on a combination of empirical criteria and statistical properties (leverages). Tide gauges provide the only in situ observations of sea level prior to the altimetry era. However, tide gauges are sparse, of questionable quality, and occasionally contradictory in their sea-level estimates. Therefore, it is essential to select the gauges very carefully. In this study, we have established a reconstruction based on empirical orthogonal functions (EOFs) of sea-level variations for the period 1950-2010 for the Arctic Ocean, constrained by tide gauge records, using the basic approach of Church et al. (2004). A major challenge is the sparsity of both satellite and tide gauge data beyond what can be covered with interpolation, necessitating a time-variable selection of tide gauges and the use of an ocean circulation model to provide gridded time series of sea level. As a surrogate for satellite altimetry, we have used the Drakkar ocean model to yield the EOFs. We initially evaluate the tide gauges through empirical criteria to reject obvious outlier gauges. Subsequently, we evaluate the "influence" of each Arctic tide gauge on the EOF-based reconstruction through the use of statistical leverage and use this as an indication in selecting appropriate tide gauges, in order to procedurally identify poor-quality data while still including as much data as possible. To accommodate sparse or contradictory tide gauge data, careful preprocessing and regularization of the reconstruction model are found to make a substantial difference to the quality of the reconstruction and the ability to select appropriate tide gauges for a reliable reconstruction. This is an especially important consideration for the Arctic, given the limited amount of data available. Thus, such a tide gauge selection study can be considered a precondition for further studies of Arctic sea

  6. Weather & Weather Maps. Teacher's Manual.

    ERIC Educational Resources Information Center

    Metro, Peter M.; Green, Rachel E.

    This guide is intended to provide an opportunity for students to work with weather symbols used for reporting weather. Also included are exercises in location of United States cities by latitude and longitude, measurement of distances in miles and kilometers, and prediction of weather associated with various types of weather fronts. (RE)

  7. Source apportionment of PM2.5 at multiple sites in Venice (Italy): Spatial variability and the role of weather

    NASA Astrophysics Data System (ADS)

    Masiol, Mauro; Squizzato, Stefania; Rampazzo, Giancarlo; Pavoni, Bruno

    2014-12-01

    This study investigates the chemical speciation of fine particulate matter (PM2.5) collected at three sites in the Venice area, eastern Po Valley (Italy). This area is one of the few hot spots left in Europe where levels of PM2.5 frequently breach EU target values and cause a serious risk for public health. Elemental composition, inorganic ions and polycyclic aromatic hydrocarbon concentrations were quantified in 448 PM2.5 samples and the multiple-site PMF receptor model was based on the elemental and inorganic ion data. Six factors associated with potential sources were quantified, namely, secondary sulfate, ammonium nitrate and combustions, fossil fuels, traffic, industrial and glassmaking. Source apportionment results were further processed using a series of chemometric tools for returning additional information about the seasonal and spatial changes of factors extracted by the PMF analysis. In addition, PMF results were also studied in combination with weather conditions and PAH concentrations revealing that sources of secondary nitrate and sulfate are homogeneously distributed throughout the area, while remaining pollutant sources may have a distinct origin. PMF results were cluster analyzed to sort out samples with similar source profiles and then the wind roses of grouped samples were examined to assess the role of wind speed and direction on PM2.5 pollution and chemistry. The tested tools and the results obtained can be used for air quality assessment studies and air pollution reduction strategies.

  8. Biting behaviour of Tabanidae on cattle in mountainous summer pastures, Pyrenees, France, and effects of weather variables.

    PubMed

    Baldacchino, F; Puech, L; Manon, S; Hertzog, Lionel R; Jay-Robert, P

    2014-08-01

    In France, during the summer, cattle in mountainous pastures can be highly exposed to tabanid bites. The persistent biting behaviour of tabanids not only causes disturbance, but is also responsible for transmitting diseases, such as bovine besnoitiosis. The purpose of this study was to better identify the level of tabanid annoyance on cattle by means of insect trapping and direct observation of cows. Tabanids were active during the entire daily observation period (10:00-16:00), except for Haematopota sp., which were less active in the morning. The tabanids collected in Nzi traps were generally representative of those that landed on cattle, except for Haematopota sp., as Nzi traps were not very effective for these species. The preferred feeding sites for most species appeared to be cow's legs or udder. Leg stamping was the defensive reaction most related to a tabanid alighting on a host. Generalized linear mixed models showed that the parameters associated with tabanid landings on hosts were related to weather and altitude, but not to landscape structure. Increased landings were mostly associated with the higher temperatures and lower wind speeds at midday, but some differences were observed between species. The results indicate that cattle-protection measures should be taken during the peak of tabanid abundance when climatic conditions favour intense biting activity. Nzi traps set close to livestock were very effective to catch tabanids and could help in reducing the annoyance caused by horse flies. PMID:24622151

  9. Evaluating effects of climate variability, extreme weather events and thinning on carbon and water exchanges in managed temperate forests in eastern Canada

    NASA Astrophysics Data System (ADS)

    Arain, M.; Brodeur, J. J.; Trant, J.; Thorne, R.; Peichl, M.; Kula, M.; Parsaud, A.; Khader, R.

    2013-12-01

    In this study the impact of climate variability and extreme weather events on gross ecosystem productivity (GEP), ecosystem respiration (RE), net ecosystem productivity (NEP) and evapotranspiration (E) is evaluated in an age-sequence (74-, 39- and 11-years old) of temperate pine (Pinus strobus L.) forests, north of Lake Erie in southern Ontario, Canada using ten years (2003-2012) of eddy covariance flux and meteorological data. Fluxes from conifer stands are also compared with measurements made in an 80-year-old deciduous (Carolinian) forest, established in 2012. All four sites are managed forests and part of the Turkey Point Flux Station and global Fluxnet. Ten-year mean NEP values were 169 (75 to 312), 371 (305 to 456, over 2008-2012) and 141 (-10 to 420) g C/m2/year in the 74-, 39-, and 11-year-old stand, respectively, while mean NEP in the 80-year-old deciduous stand was 286 g C/m2/year in 2012. This region is affected by low frequency climate oscillations, such as El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO). The study period experienced four distinct extreme weather patterns: warm and dry springs in 2005 and 2012, extremely wet and warm summer in 2006, a summer drought in 2007 and warm summers in 2010 and 2012. In February-March 2012, the 74-year-old stand was selectively thinned and approximately 30% of trees were removed to improve light and water availability and stimulate growth of remaining trees. Thinning and warm/dry spring reduced NEP in the first post-thinning year, with mean annual NEP of 75 g C/m2/year in 2012. Increased supply of dead organic matter and warm temperatures in 2012 increased RE much more than GEP, resulting in lower annual NEP. Heat stress and drought in spring of 2005 reduced NEP of the 74-year stand to 78 g C/m2/year. The impact of this extreme weather event on NEP was similar to that observed in 2012 when stand experienced a drastic structural change, dry spring and warm temperatures throughout the

  10. WEATHER ON THE NEAREST BROWN DWARFS: RESOLVED SIMULTANEOUS MULTI-WAVELENGTH VARIABILITY MONITORING OF WISE J104915.57–531906.1AB

    SciTech Connect

    Biller, Beth A.; Crossfield, Ian J. M.; Mancini, Luigi; Ciceri, Simona; Kopytova, Taisiya G.; Bonnefoy, Mickaël; Deacon, Niall R.; Schlieder, Joshua E.; Buenzli, Esther; Brandner, Wolfgang; Bailer-Jones, Coryn A. L.; Henning, Thomas; Goldman, Bertrand; Southworth, John; Allard, France; Homeier, Derek; Freytag, Bernd; Greiner, Jochen

    2013-11-20

    We present two epochs of MPG/ESO 2.2 m GROND simultaneous six-band (r'i'z' JHK) photometric monitoring of the closest known L/T transition brown dwarf binary WISE J104915.57–531906.1AB. We report here the first resolved variability monitoring of both the T0.5 and L7.5 components. We obtained 4 hr of focused observations on the night of 2013 April 22 (UT), as well as 4 hr of defocused (unresolved) observations on the night of 2013 April 16 (UT). We note a number of robust trends in our light curves. The r' and i' light curves appear to be anti-correlated with z' and H for the T0.5 component and in the unresolved light curve. In the defocused dataset, J appears correlated with z' and H and anti-correlated with r' and i', while in the focused dataset we measure no variability for J at the level of our photometric precision, likely due to evolving weather phenomena. In our focused T0.5 component light curve, the K band light curve displays a significant phase offset relative to both H and z'. We argue that the measured phase offsets are correlated with atmospheric pressure probed at each band, as estimated from one-dimensional atmospheric models. We also report low-amplitude variability in i' and z' intrinsic to the L7.5 component.

  11. Boundary-layer turbulent processes and mesoscale variability represented by numerical weather prediction models during the BLLAST campaign

    NASA Astrophysics Data System (ADS)

    Couvreux, Fleur; Bazile, Eric; Canut, Guylaine; Seity, Yann; Lothon, Marie; Lohou, Fabienne; Guichard, Françoise; Nilsson, Erik

    2016-07-01

    This study evaluates the ability of three operational models, with resolution varying from 2.5 to 16 km, to predict the boundary-layer turbulent processes and mesoscale variability observed during the Boundary Layer Late-Afternoon and Sunset Turbulence (BLLAST) field campaign. We analyse the representation of the vertical profiles of temperature and humidity and the time evolution of near-surface atmospheric variables and the radiative and turbulent fluxes over a total of 12 intensive observing periods (IOPs), each lasting 24 h. Special attention is paid to the evolution of the turbulent kinetic energy (TKE), which was sampled by a combination of independent instruments. For the first time, this variable, a central one in the turbulence scheme used in AROME and ARPEGE, is evaluated with observations.In general, the 24 h forecasts succeed in reproducing the variability from one day to another in terms of cloud cover, temperature and boundary-layer depth. However, they exhibit some systematic biases, in particular a cold bias within the daytime boundary layer for all models. An overestimation of the sensible heat flux is noted for two points in ARPEGE and is found to be partly related to an inaccurate simplification of surface characteristics. AROME shows a moist bias within the daytime boundary layer, which is consistent with overestimated latent heat fluxes. ECMWF presents a dry bias at 2 m above the surface and also overestimates the sensible heat flux. The high-resolution model AROME resolves the vertical structures better, in particular the strong daytime inversion and the thin evening stable boundary layer. This model is also able to capture some specific observed features, such as the orographically driven subsidence and a well-defined maximum that arises during the evening of the water vapour mixing ratio in the upper part of the residual layer due to fine-scale advection. The model reproduces the order of magnitude of spatial variability observed at

  12. Evaluation of a global internal-tide resolving and submesoscale admitting ocean simulation

    NASA Astrophysics Data System (ADS)

    Ubelmann, C.; Menemenlis, D.; Fu, L. L.; Zhao, Z.

    2014-12-01

    We will present ongoing evaluation of a global ocean and sea ice configuration of the Massachusetts Institute of Technology general circulation model (MITgcm) that has 0.75 to 2.2 km horizontal grid spacing and 1-m thick vertical levels near the surface. Surface boundary conditions are from the 0.14-degree European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric operational model analysis, starting in 2011, including atmospheric pressure forcing. The simulation also includes tidal forcing. A unique feature of this simulation is that we save hourly output of full 3-dimensional model prognostic variables, making it a remarkable tool for the study of ocean processes and for the simulation of satellite observations. Although this initial simulation was run without ocean data constraints, it already presents very interesting features and interactions between an exceptionally wide range of scales. The simulation resolves geostrophic eddies and internal tides and admits submesoscale variability and unbalanced dynamics such as internal waves at non-tidal frequencies.We will present some evaluation of these different components based on altimetry observations and moorings. As a first result, the internal tides for the major tidal components have overall realistic amplitudes and spatial patterns compared to independent analyses from altimetry, although some discrepancies arise in equatorial regions. Despite discrepancies with observations, this simulation already constitutes an extremely useful tool for ocean process studies and for satellite observation system experiments, for example, in preparation for the Surface Water and Ocean Topography (SWOT) mission. As a preliminary exercise, the simulation has been tested in the SWOT simulator developed at the Jet Propulsion Laboratory (Fu et al., in this session). Some illustrations of the challenges will be presented.

  13. The magnetic tides of Honolulu

    USGS Publications Warehouse

    Love, Jeffrey J.; Rigler, Erin Joshua

    2013-01-01

    We review the phenomenon of time-stationary, periodic quiet-time geomagnetic tides. These are generated by the ionospheric and oceanic dynamos, and, to a lesser-extent, by the quiet-time magnetosphere, and they are affected by currents induced in the Earth's electrically conducting interior. We examine historical time series of hourly magnetic-vector measurements made at the Honolulu observatory. We construct high-resolution, frequency-domain Lomb-periodogram and maximum-entropy power spectra that reveal a panorama of stationary harmonics across periods from 0.1 to 10000.0-d, including harmonics that result from amplitude and phase modulation. We identify solar-diurnal tides and their annual and solar-cycle sideband modulations, lunar semi-diurnal tides and their solar-diurnal sidebands, and tides due to precession of lunar eccentricity and nodes. We provide evidence that a method intended for separating the ionospheric and oceanic dynamo signals by midnight subsampling of observatory data time series is prone to frequency-domain aliasing. The tidal signals we summarize in this review can be used to test our fundamental understanding of the dynamics of the quiet-time ionosphere and magnetosphere, induction in the ocean and in the electrically conducting interior of the Earth, and they are useful for defining a quiet-time baseline against which magnetospheric-storm intensity is measured.

  14. Barometric and Earth Tide Correction

    Energy Science and Technology Software Center (ESTSC)

    2005-11-10

    BETCO corrects for barometric and earth tide effects in long-term water level records. A regression deconvolution method is used ot solve a series of linear equations to determine an impulse response function for the well pressure head. Using the response function, a pressure head correction is calculated and applied.

  15. The magnetic tides of Honolulu

    NASA Astrophysics Data System (ADS)

    Love, J. J.; Rigler, E. J.

    2013-12-01

    We review the phenomenon of time-stationary, periodic quiet-time geomagnetic tides. These are generated by the ionospheric and oceanic dynamos, and, to a lesser-extent, by the quiet-time magnetosphere, and they are affected by currents induced in the Earth's electrically conducting interior. We examine historical time series of hourly magnetic-vector measurements made at the Honolulu observatory. We construct high-resolution, frequency-domain Lomb-periodogram and maximum-entropy power spectra that reveal a panorama of stationary harmonics across periods from 0.1 to 10000.0-d, including harmonics that result from amplitude and phase modulation. We identify solar-diurnal tides and their annual and solar-cycle sideband modulations, lunar semi-diurnal tides and their solar-diurnal sidebands, and tides due to precession of lunar eccentricity and nodes. We provide evidence that a method intended for separating the ionospheric and oceanic dynamo signals by midnight subsampling of observatory data time series is prone to frequency-domain aliasing. The tidal signals we summarize in this review can be used to test our fundamental understanding of the dynamics of the quiet-time ionosphere and magnetosphere, induction in the ocean and in the electrically conducting interior of the Earth, and they are useful for defining a quiet-time baseline against which magnetospheric-storm intensity is measured.

  16. Secular Changes in the Solar Semidiurnal Tide of the Western North Atlantic Ocean

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    2009-01-01

    An analysis of twentieth century tide gauge records reveals that the solar semidiurnal tide S, has been decreasing in amplitude along the eastern coast of North America and at the mid-ocean site Bermuda. In relative terms the observed rates are unusually large, of order 10% per century. Periods of greatest change, however, are inconsistent among the stations, and roughly half the stations show increasing amplitude since the late 1990s. Excepting the Gulf of Maine, lunar tides are either static or slightly increasing in amplitude; a few stations show decreases. Large changes in solar, but not lunar, tides suggest causes related to variable radiational forcing, but the hypothesis is at present unproven. Citation: Ray, R. D. (2009), Secular changes in the solar semidiurnal tide of the western North Atlantic Ocean

  17. Variable strength of forest stand attributes and weather conditions on the questing activity of Ixodes ricinus ticks over years in managed forests.

    PubMed

    Lauterbach, Ralf; Wells, Konstans; O'Hara, Robert B; Kalko, Elisabeth K V; Renner, Swen C

    2013-01-01

    Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008-2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming. PMID:23372852

  18. Variable Strength of Forest Stand Attributes and Weather Conditions on the Questing Activity of Ixodes ricinus Ticks over Years in Managed Forests

    PubMed Central

    Lauterbach, Ralf; Wells, Konstans; O'Hara, Robert B.; Renner, Swen C.

    2013-01-01

    Given the ever-increasing human impact through land use and climate change on the environment, we crucially need to achieve a better understanding of those factors that influence the questing activity of ixodid ticks, a major disease-transmitting vector in temperate forests. We investigated variation in the relative questing nymph densities of Ixodes ricinus in differently managed forest types for three years (2008–2010) in SW Germany by drag sampling. We used a hierarchical Bayesian modeling approach to examine the relative effects of habitat and weather and to consider possible nested structures of habitat and climate forces. The questing activity of nymphs was considerably larger in young forest successional stages of thicket compared with pole wood and timber stages. Questing nymph density increased markedly with milder winter temperatures. Generally, the relative strength of the various environmental forces on questing nymph density differed across years. In particular, winter temperature had a negative effect on tick activity across sites in 2008 in contrast to the overall effect of temperature across years. Our results suggest that forest management practices have important impacts on questing nymph density. Variable weather conditions, however, might override the effects of forest management practices on the fluctuations and dynamics of tick populations and activity over years, in particular, the preceding winter temperatures. Therefore, robust predictions and the detection of possible interactions and nested structures of habitat and climate forces can only be quantified through the collection of long-term data. Such data are particularly important with regard to future scenarios of forest management and climate warming. PMID:23372852

  19. The "dirty weather" diaries of Reverend Richard Davis: insights about early colonial-era meteorology and climate variability for northern New Zealand, 1839-1851

    NASA Astrophysics Data System (ADS)

    Lorrey, Andrew M.; Chappell, Petra R.

    2016-03-01

    Reverend Richard Davis (1790-1863) was a colonial-era missionary stationed in the Far North of New Zealand who was a key figure in the early efforts of the Church Mission Society. He kept meticulous meteorological records for the early settlements of Waimate North and Kaikohe, and his observations are preserved in a two-volume set in the Sir George Grey Special Collections in the Auckland Central Library. The Davis diary volumes are significant because they constitute some of the earliest land-based meteorological measurements that were continually chronicled for New Zealand. The diary measurements cover nine years within the 1839-1851 time span that are broken into two parts: 1839-1844 and 1848-1851. Davis' meteorological recordings include daily 9 a.m. and noon temperatures and midday pressure measurements. Qualitative comments in the diary note prevailing wind flow, wind strength, cloud cover, climate variability impacts, bio-indicators suggestive of drought, and notes on extreme weather events. "Dirty weather" comments scattered throughout the diary describe disturbed conditions with strong winds and driving rainfall. The Davis diary entries coincide with the end of the Little Ice Age (LIA) and they indicate southerly and westerly circulation influences and cooler winter temperatures were more frequent than today. A comparison of climate field reconstructions derived from the Davis diary data and tree-ring-based winter temperature reconstructions are supported by tropical coral palaeotemperature evidence. Davis' pressure measurements were corroborated using ship log data from vessels associated with iconic Antarctic exploration voyages that were anchored in the Bay of Islands, and suggest the pressure series he recorded are robust and can be used as "station data". The Reverend Davis meteorological data are expected to make a significant contribution to the Atmospheric Circulation Reconstructions across the Earth (ACRE) project, which feeds the major data

  20. The "Dirty Weather" diaries of Reverend Richard Davis: insights about early Colonial-era meteorology and climate variability for Northern New Zealand, 1839-1851

    NASA Astrophysics Data System (ADS)

    Lorrey, A. M.; Chappell, P. R.

    2015-08-01

    Reverend Richard Davis (1790-1863) was a Colonial-era missionary stationed in the Far North of New Zealand who was a key figure in the early efforts of the Church Mission Society. He kept meticulous meteorological records for the early settlements of Waimate North and Kaikohe, and his observations are preserved in a two-volume set in the rare manuscripts archive at the Auckland City Library. The Davis diary volumes are significant because they constitute some of the earliest land-based meteorological measurements that were continually chronicled for New Zealand. The diary measurements cover nine years within the 1839-1851 timespan that are broken into two parts: 1839-1844 and 1848-1851. Davis' meteorological recordings include daily 9 AM and noon temperatures and mid-day pressure measurements. Qualitative comments in the diary note prevailing wind flow, wind strength, cloud cover, climate variability impacts, bio-indicators suggestive of drought, and notes on extreme weather events. "Dirty weather" comments scattered throughout the diary describe disturbed conditions with strong winds and driving rainfall. The Davis diary entries coincide with the end of the Little Ice Age (LIA) and they indicate southerly and westerly circulation influences and cooler winter temperatures were more frequent than today. A comparison of climate field reconstructions derived from the Davis diary data and tree ring-based winter temperature reconstructions are supported by tropical coral palaeotemperature evidence. Davis' pressure measurements were corroborated using ship log data from vessels associated with iconic Antarctic exploration voyages that were anchored in the Bay of Islands, and suggest the pressure series he recorded are robust and can be used as `station data'. The Reverend Davis meteorological data are expected to make a significant contribution to the Atmospheric Circulation Reconstructions across the Earth (ACRE) project, which feeds the major data requirements for the

  1. Weather on Other Worlds. I. Detection of Periodic Variability in the L3 Dwarf DENIS-P J1058.7-1548 with Precise Multi-wavelength Photometry

    NASA Astrophysics Data System (ADS)

    Heinze, Aren N.; Metchev, Stanimir; Apai, Daniel; Flateau, Davin; Kurtev, Radostin; Marley, Mark; Radigan, Jacqueline; Burgasser, Adam J.; Artigau, Étienne; Plavchan, Peter

    2013-04-01

    Photometric monitoring from warm Spitzer reveals that the L3 dwarf DENIS-P J1058.7-1548 varies sinusoidally in brightness with a period of 4.25^{+0.26}_{-0.16} hr and an amplitude of 0.388% ± 0.043% (peak-to-valley) in the 3.6 μm band, confirming the reality of a 4.31 ± 0.31 hr periodicity detected in J-band photometry from the SOAR telescope. The J-band variations are a factor of 2.17 ± 0.35 larger in amplitude than those at 3.6 μm, while 4.5 μm Spitzer observations yield a 4.5 μm/3.6 μm amplitude ratio of only 0.23 ± 0.15, consistent with zero 4.5 μm variability. This wide range in amplitudes indicates rotationally modulated variability due to magnetic phenomena and/or inhomogeneous cloud cover. Weak Hα emission indicates some magnetic activity, but it is difficult to explain the observed amplitudes by magnetic phenomena unless they are combined with cloud inhomogeneities (which might have a magnetic cause). However, inhomogeneous cloud cover alone can explain all our observations, and our data align with theory in requiring that the regions with the thickest clouds also have the lowest effective temperature. Combined with published vsin (i) results, our rotation period yields a 95% confidence lower limit of R * >= 0.111 R ⊙, suggesting upper limits of 320 Myr and 0.055 M ⊙ on the age and mass. These limits should be regarded cautiously because of ~3σ inconsistencies with other data; however, a lower limit of 45° on the inclination is more secure. DENIS-P J1058.7-1548 is only the first of nearly two dozen low-amplitude variables discovered and analyzed by the Weather on Other Worlds project.

  2. Assessing change of environmental dynamics by legislation in Japan, using red tide occurrence in Ise Bay as an indicator.

    PubMed

    Suzuki, Chika

    2016-01-30

    Tokyo Bay, Ise Bay, and the Seto Inland Sea are the total pollutant load control target areas in Japan. A significant correlation between the incidence of red tides and water quality has been observed in the Seto Inland Sea (Honjo, 1991). However, while red tides also occur in Ise Bay and Tokyo Bay, similar correlations have not been observed. Hence, it is necessary to understand what factors cause red tides to effectively manage these semi-closed systems. This study aims to investigate the relationship between the dynamics of the Red Tide Index and nitrogen regulation as well as phosphorus regulation, even in Ise Bay where, unlike Tokyo Bay, there are few observation items, by selecting a suitable objective variable. The introduction of a new technique that uses the Red Tide Index has revealed a possibility that the total pollution load control has influenced the dynamics of red tide blooms in Ise Bay. PMID:26337227

  3. Estimating Tides from a Planetary Flyby Mission

    NASA Astrophysics Data System (ADS)

    Mazarico, Erwan; Genova, Antonio; Smith, David; Zuber, Maria; Sun, Xiaoli

    2014-05-01

    Previous and current laser altimeter instruments (e.g. MOLA, NLR, LOLA, MLA) acquired measurements in orbit to provide global topography and study the surface and sub-surface properties of planetary bodies. We show that altimetric data from multiple flybys can make significant contributions to the geophysical understanding of the target body. In particular, the detection of the body tide (e.g. surface deformation due to the tides raised by the Sun or the parent body) and the estimation of its amplitude can yield critical information about the interior structure. We conduct a full simulation of a planetary flyby mission around Europa. We use the GEODYN II program developed and maintained at NASA GSFC to process altimetric and radiometric tracking data created using truth models. The data are processed in short two-day segments (arcs) centered on each closest approach. The initial trajectory is integrated using a priori (truth) models of the planetary ephemeris, the gravity field, the tidal Love numbers k2 and h2 (which describe the amplitudes of the time-variable tidal potential and the time-variable radial deformation respectively). The gravity field is constructed using a Kaula-like power law and scaling considerations from other planetary bodies. The global-scale static topography is also chosen to follow a power law, and higher-resolution local maps consistent with recent stereo-topography work are used to assess the expected variations along altimetric profiles. We assume realistic spacecraft orientation to drive a spacecraft macro-model and model the solar radiation pressure acceleration. Radiometric tracking data are generated from the truth trajectory accounting for geometry (occultations by Europa or Jupiter or the Sun), DSN visibility and scheduling (8h per day) and measurement noise (Ka-band quality, plasma noise). Doppler data have a 10-second integration step while Range data occur every 5 minutes. The altimetric data are generated using realistic

  4. Stratospheric Tides and Data Assimilation

    NASA Technical Reports Server (NTRS)

    Swinbank, R.; Orris, R. L.; Wu, D. L.

    1999-01-01

    In the upper stratosphere, the atmosphere exhibits significant diurnal and semi-diurnal tidal variations, with typical amplitude of about 2K in mid-latitudes. In this paper we examine how well the tidal variations in temperature are represented by the Goddard Geodesic Earth Orbiting Satellite (GEOS-2) data assimilation system. We show that the GEOS-2 atmospheric model is quite successful at simulating the tidal temperature variations. However, the assimilation of satellite temperature soundings significantly damps the simulated tides. The reason is because the tides are not well represented by the satellite retrievals used by the assimilation system (which have a typical tidal amplitude of around 1K). As a result of this study, we suggest improvements that should be made to the treatment of satellite soundings by the assimilation system.

  5. Tide following wave power machine

    SciTech Connect

    Murphy, J.T.

    1982-09-21

    At least two spaced piers are constructed on a suitable tidal beach extending from the shore into the water a predetermined distance to meet the first breaking waves at low tide. A carriage is movably supported on the piers on an inclined path, the carriage having a frame supporting a pair of spaced sprocket wheels on each end over which is passed an endless belt. The ends of a plurality of blades are secured to the chain in spaced relation completely thereabout. Each sprocket wheels closest to shore is connected to a gear train for transmitting the torque generated by the wave action to a power belt extending along each pier to a transducer located at the shore end of the pier. Means are provided for moving the carriage on the pier on an inclined path in and out from the shore to meet the level of the changing tide so as to continuously generate power throughout the tidal wave.

  6. The magnetic tides of Honolulu

    NASA Astrophysics Data System (ADS)

    Love, Jeffrey J.; Rigler, E. Joshua

    2014-06-01

    We review and analyse the phenomenon of time-invariant, periodic geomagnetic tides. These are generated by the deterministic physics of the ionospheric and oceanic dynamos, and, to a lesser extent, by the solar-quiet magnetosphere, and they are affected by currents induced in the Earth's electrically conducting interior. Using a long historical time-series of hourly magnetic vector measurements made at the Honolulu observatory, we construct high-resolution, frequency-domain power spectra across periods from 0.1 to 10 000.0 d using maximum-entropy and Lomb periodogram algorithms. Recognizing that harmonics corresponding to fundamental forcing periods can, themselves, have amplitude and phase modulation driven by other forcing harmonics, we identify solar-diurnal tides and their annual and solar-cycle sideband modulations, lunar semidiurnal tides and their solar-diurnal sidebands, and tides due to precession of lunar eccentricity and nodes. In contrast to reports by other investigators, we cannot identify tidal signals that might be related to the 22-yr Hale cycle, the Chandler wobble and the quasi-biennial oscillation. Using a least-squares algorithm to estimate the amplitudes and phases of individual tidal constituents, we construct synthetic model time-series that are representative of geomagnetic tidal variation. The signals summarized in this report can be used to test fundamental understanding of the dynamics of the solar-quiet ionosphere and magnetosphere, the ocean and the electrically conducting interior of the Earth, and they can be used to specify a quiet-time baseline against which magnetospheric storm disturbance can be measured.

  7. Nonmigrating diurnal tides in the equatorial middle atmosphere

    SciTech Connect

    Lieberman, R.S.

    1992-01-01

    Data from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to analyze the diurnal tides in the middle atmosphere. A novel aspect of this study is the emphasis on the relative importance of the nonmigrating components. These modes display a high degree of temporal variability during the LIMS observing period, and contribute substantially to the diurnal signal in wind and temperature. Their observed vertical phase variations are variable; however there is evidence for upward energy propagation. It has long been hypothesized that nonmigrating tides are driven by the diurnally-varying zonally asymmetric tropospheric heating constituents. This premise is examined by employing a linear tidal model to simulate the response of the atmosphere to realistic tidal drives. These quantities are calculated from the NCAR Community Climate Model. The large-scale CCM2 diurnal surface pressure, OLR and hydrology are well simulated under July and January conditions. The CCM2 diurnal fields of short-wave radiative, convective and diffusive PBL heating are used as input to a linear tidal model with Newtonian cooling. This model successfully reproduces many observed features of the migrating and nonmigrating diurnal surface pressure tides at low latitudes. In the middle atmosphere, tropospheric solar heating is the dominant source of the migrating tide. The zonal means and eastward migrating wavenumber one components are also associated with radiative heating. The eastward migrating wavenumber three pattern is strongly linked to the dry and moist convective heating as well. The observed eastward migrating tides are harder to simulate, due in part to the failure of the linear model to incorporate the dissipative effects to which they are prone.

  8. Weight, gravitation, inertia, and tides

    NASA Astrophysics Data System (ADS)

    Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe

    2015-11-01

    This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.

  9. Assessing the role of spatial rainfall variability on watersheds response using weather radar A case study in the Gard region, France

    NASA Astrophysics Data System (ADS)

    Anggraheni, Evi; Payrastre, Olivier; Emmanuel, Isabelle; Andrieu, Herve

    2014-05-01

    The consideration of spatial rainfall variability in hydrological modeling is not only an important scientific issue but also, with the current development of high resolution rainfall data from weather radars, an increasing request from managers of sewerage networks and from flood forecasting services. Although the literature on this topic is already significant, at this time the conclusions remain contrasted. The impact of spatial rainfall variability on the hydrological responses appears to highly depend both on the organization of rainfall fields and on the watershed characteristics. The objective of the study presented here is to confirm and analyze the high impact of spatial rainfall variability in the specific context of flash floods. The case study presented is located in the Gard region in south east of France and focuses on four events which occurred on 13 different watersheds in 2008. The hydrological behaviors of these watersheds have been represented by the distributed rainfall - runoff model CINECAR, which already proved to well represent the hydrological responses in this region (Naulin et al., 2013). The influence of spatial rainfall variability has been studied here by considering two different rainfall inputs: radar data with a resolution of 1 km x 1 km and the spatial average rainfall over the catchment. First, the comparison between simulated and measured hydrographs confirms the good performances of the model for intense rainfall events, independently of the level of spatial rainfall variability of these events. Secondly, the simulated hydrographs obtained from radar data are taken as reference and compared to those obtained from the average rainfall inputs by computing two values: the time difference and the difference of magnitude between the simulated peaks discharge. The results highly depend on the rainfall event considered, and on the level of organization of the spatial rainfall variability. According to the model, the behavior of the

  10. Coordinated radar observations of atmospheric diurnal tides in equatorial regions

    NASA Astrophysics Data System (ADS)

    Tsuda, Toshitaka; Ohnishi, Kazunori; Isoda, Fusako; Nakamura, Takuji; Vincent, Robert A.; Reid, Iain M.; Harijono, Sri Woro B.; Sribimawati, Tien; Nuryanto, Agus; Wiryosumarto, Harsono

    1999-07-01

    The long-term behavior of atmospheric tides in the mesosphere and lower thermosphere has been observed with the meteor wind radar (MWR) in Jakarta, Indonesia (6°S, 107°E) from November 1992 to August 1997. The amplitudes and phases of the diurnal tides show systematic seasonal variations, particularly distinct in the meridional component. In addition, substantial interannual variability is evident, characterized by a biennial periodicity of tidal parameters, and considerably small tidal amplitudes exclusively seen in 1996. The MWR results are compared with the Global Scale Wave Model (GSWM) as well as MF radar data collected in two equatorial sites in Pontianak (0.03°N, 109°E) and Christmas Island (2°N, 158°W) for November 1995-July 1997 and January 1996-October 1997, respectively. Comparison studies of these radar data have revealed the detailed latitudinal structure of the diurnal tide near the equator. The GSWM has successfully described the general characteristics of the radar results, although some discrepancies are recognized. In 1996 when radar data are available at all the three sites, the monthly mean values of tidal amplitudes at 90 km agreed very well between Jakarta and Pontianak, while significant discrepancy was found for Christmas Island, suggesting the existence of geographical effects such as non-migrating tides.

  11. Influence analysis of Arctic tide gauges using leverages

    NASA Astrophysics Data System (ADS)

    Limkilde Svendsen, Peter; Baltazar Andersen, Ole; Aasbjerg Nielsen, Allan

    2014-05-01

    Reconstructions of historical sea level in the Arctic Ocean are fraught with difficulties related to lack of data, uneven distribution of tide gauges and seasonal ice cover. Considering the period from 1950 to the present, we attempt to identify conspicuous tide gauges in an automated way, using the statistical leverage of each individual gauge. This may be of help in determining appropriate procedures for data preprocessing, of particular importance for the Arctic area as the GIA is hard to constrain and many gauges are located on rivers. We use a model based on empirical orthogonal functions from a calibration period, in this preliminary case Drakkar ocean model data, which are forced using historical tide gauge data from the PSMSL database. The resulting leverage for each tide gauge may indicate that it represents a distinct mode of variability, or that its time series is perturbed in a way inappropriate for the reconstruction so that it should be removed from the reconstruction model altogether. Therefore, the characteristics of the high-leverage gauges are examined in detail.

  12. SAMI3/SD-WACCM-X simulations of ionospheric variability during northern winter 2009

    NASA Astrophysics Data System (ADS)

    McDonald, S. E.; Sassi, F.; Mannucci, A. J.

    2015-09-01

    We have performed simulations using the Naval Research Laboratory's physics-based model of the ionosphere, Sami3 is A Model of the Ionosphere (SAMI3), to illustrate how neutral wind dynamics is responsible for day-to-day variability of the ionosphere. We have used neutral winds specified from the extended version of the specified dynamics Whole Atmosphere Community Climate Model (SD-WACCM-X), in which meteorology below 92 km is constrained by atmospheric specifications from an operational weather forecast model and reanalysis. To assess the realism of the simulations against observations, we have carried out a case study during January-February 2009, a dynamically disturbed time characterized by a sudden stratospheric warming (SSW) commencing 24 January 2009. Model results are compared with total electron content (TEC) from Jet Propulsion Laboratory global ionospheric maps. We show that SAMI3/SD-WACCM-X captures longitudinal variability in the equatorial ionization anomaly associated with nonmigrating tides, with strongest contributions coming from the diurnal eastward wave number 2 (DE2) and DE3. Both migrating and nonmigrating tides contribute to significant day-to-day variability, with TEC varying up to 16%. Our simulation during the SSW period reveals that at the Jicamarca longitude (285°E) on 27 January 2009 nonmigrating tides contribute to an enhancement of the electron density in the morning followed by a decrease in the afternoon. An enhancement of the semidiurnal eastward wave number 2 (SE2) and SE3 nonmigrating tides, likely associated with the appearance of the SSW, suggests that these tides increase the longitudinal variability of the SSW impact on the ionosphere. The conclusion is that realistic meteorology propagating upward from the lower atmosphere influences the dynamo region and reproduces aspects of the observed variability in the ionosphere.

  13. Effects of Ocean Tide Models on Gnss-Estimated Ztd and Pwv in Turkey

    NASA Astrophysics Data System (ADS)

    Gurbuz, G.; Jin, S.; Mekik, C.

    2015-12-01

    Global Navigation Satellite System (GNSS) observations can precisely estimate the total zenith tropospheric delay (ZTD) and precipitable water vapour (PWV) for weather prediction and atmospheric research as a continuous and all-weather technique. However, apart from GNSS technique itself, estimations of ZTD and PWV are subject to effects of geophysical models with large uncertainties, particularly imprecise ocean tide models in Turkey. In this paper, GNSS data from Jan. 1st to Dec. 31st of 2014 are processed at 4 co-located GNSS stations (GISM, DIYB, GANM, and ADAN) with radiosonde from Turkish Met-Office along with several nearby IGS stations. The GAMIT/GLOBK software has been used to process GNSS data of 30-second sample using the Vienna Mapping Function and 10° elevation cut-off angle. Also tidal and non-tidal atmospheric pressure loadings (ATML) at the observation level are also applied in GAMIT/GLOBK. Several widely used ocean tide models are used to evaluate their effects on GNSS-estimated ZTD and PWV estimation, such as IERS recommended FES2004, NAO99b from a barotropic hydrodynamic model, CSR4.0 obtained from TOPEX/Poseidon altimetry with the model FES94.1 as the reference model and GOT00 which is again long wavelength adjustments of FES94.1 using TOPEX/Poseidon data at 0.5 by 0.5 degree grid. The ZTD and PWV computed from radiosonde profile observations are regarded as reference values for the comparison and validation. In the processing phase, five different strategies are taken without ocean tide model and with four aforementioned ocean tide models, respectively, which are used to evaluate ocean tide models effects on GNSS-estimated ZTD and PWV estimation through comparing with co-located Radiosonde. Results showed that ocean tide models have greatly affected the estimation of the ZTD in centimeter level and thus the precipitable water vapour in millimeter level, respectively at stations near coasts. The ocean tide model FES2004 that is the product of

  14. Titan's Eccentricity Tides

    NASA Astrophysics Data System (ADS)

    Iess, L.; Jacobson, R.; Ducci, M.; Stevenson, D. J.; Lunine, J. I.; Armstrong, J. W.; Asmar, S.; Racioppa, P.; Rappaport, N. J.; Tortora, P.

    2011-12-01

    of the body[2]. In this previous analysis, tidal variations of the gravity field were neglected. Thanks to the availability of two additional flybys (on May 20, 2010 and Feb. 18, 2011) and the improvement of the data analysis tools, also the variable component of the gravity field could be estimated with good accuracy. In order to increase the confidence in the results, two independent analyses have been carried out, both resulting in very close and statistically indistinguishable values for k2. While the results are compatible (at the low end of k2) with interior models made up by a high viscosity core and a near-surface liquid water layer, the centroid of the k2 values requires additionally that some substantial fraction of the interior -ice mantle or core- be capable of significant deformations over time scales of the orbital period. References [1] Rappaport, N.J. et al., 2008. Can Cassini detect a subsurface ocean in Titan from gravity measurements?, Icarus, Vol. 194, No. 2. [2] Iess, L. et al., 2010. Gravity field, shape, and moment of inertia of Titan. Science 327, 1367-1369.

  15. Waste glass weathering

    SciTech Connect

    Bates, J.K.; Buck, E.C.

    1993-12-31

    The weathering of glass is reviewed by examining processes that affect the reaction of commercial, historical, natural, and nuclear waste glass under conditions of contact with humid air and slowly dripping water, which may lead to immersion in nearly static solution. Radionuclide release data from weathered glass under conditions that may exist in an unsaturated environment are presented and compared to release under standard leaching conditions. While the comparison between the release under weathering and leaching conditions is not exact, due to variability of reaction in humid air, evidence is presented of radionuclide release under a variety of conditions. These results suggest that both the amount and form of radionuclide release can be affected by the weathering of glass.

  16. The pole tide in deep oceans

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1990-01-01

    The fluid-dynamical theory of the pole tide is examined by describing the oceanic response to the Chandler wobble and assessing its implications for mantle anelasticity and low-frequency ocean dynamics. The Laplace tide equations accounting for bottom friction are given, and a spherical harmonic approach is delineated in which the time-independent portion of the tide height is expanded. Pole-tide height and related inertia products are linearly proportional to wobble amplitude, and the final equations are modified to account for mantle elasticity and oceanic loading. Results for pole tide effects are given for various earth models with attention to the role of boundary constraints. A dynamic effect is identified which lengthens the Chandler period by about 1 day more than static lengthening, a contribution that suggests a vigorous low-frequency response. The values derived are shown to agree with previous models that do not incorporate the effects of the pole tide.

  17. Weather Instruments.

    ERIC Educational Resources Information Center

    Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

    This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

  18. Wacky Weather

    ERIC Educational Resources Information Center

    Sabarre, Amy; Gulino, Jacqueline

    2013-01-01

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

  19. Space Weather

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.

    2010-01-01

    This video provides a narrated exploration of the history and affects of space weather. It includes information the earth's magnetic field, solar radiation, magnetic storms, and how solar winds affect electronics on earth, with specific information on how space weather affects space exploration in the future.

  20. How do earth tides affect astronomers?

    NASA Technical Reports Server (NTRS)

    Sasao, T.

    1978-01-01

    Earth tides affect astronomical observations of the Earth's rotation in the following two ways: (1) verticals are deflected; and (2) the polar moment of inertia of the Earth is changed causing periodic variations in the rotation rate. The diurnal and semidiurnal tides and nutation were examined in periodic variations. Results indicate little change occured in the polar motions. Nutation observations were disturbed rather seriously by the diurnal tides.

  1. Tide effects removed from well tests

    SciTech Connect

    Aase, E.P.B.; Jelmert, T.A.; Vik, S.A.

    1995-05-01

    To avoid distorted data when analyzing well pressure tests of permeable offshore reservoirs, one needs to account for periodic ocean tidal stress. Quartz-crystal bottom hole pressure recorders provide a high resolution of reservoir pressure but also measures pressure fluctuations from tidal effects during well testing. Periodic oscillations in the reservoir pressure are due to the three mechanisms: solid earth tide; barometric tide/effect; and ocean tide. The paper uses sample data from an offshore reservoir to illustrate how tide effects can be identified in the data and the correction procedure to use to remove these effects.

  2. WEATHER ON OTHER WORLDS. I. DETECTION OF PERIODIC VARIABILITY IN THE L3 DWARF DENIS-P J1058.7-1548 WITH PRECISE MULTI-WAVELENGTH PHOTOMETRY

    SciTech Connect

    Heinze, Aren N.; Metchev, Stanimir; Apai, Daniel; Flateau, Davin; Kurtev, Radostin; Marley, Mark; Radigan, Jacqueline; Burgasser, Adam J.; Artigau, Etienne; Plavchan, Peter E-mail: stanimir.metchev@stonybrook.edu

    2013-04-20

    Photometric monitoring from warm Spitzer reveals that the L3 dwarf DENIS-P J1058.7-1548 varies sinusoidally in brightness with a period of 4.25{sup +0.26}{sub -0.16} hr and an amplitude of 0.388% {+-} 0.043% (peak-to-valley) in the 3.6 {mu}m band, confirming the reality of a 4.31 {+-} 0.31 hr periodicity detected in J-band photometry from the SOAR telescope. The J-band variations are a factor of 2.17 {+-} 0.35 larger in amplitude than those at 3.6 {mu}m, while 4.5 {mu}m Spitzer observations yield a 4.5 {mu}m/3.6 {mu}m amplitude ratio of only 0.23 {+-} 0.15, consistent with zero 4.5 {mu}m variability. This wide range in amplitudes indicates rotationally modulated variability due to magnetic phenomena and/or inhomogeneous cloud cover. Weak H{alpha} emission indicates some magnetic activity, but it is difficult to explain the observed amplitudes by magnetic phenomena unless they are combined with cloud inhomogeneities (which might have a magnetic cause). However, inhomogeneous cloud cover alone can explain all our observations, and our data align with theory in requiring that the regions with the thickest clouds also have the lowest effective temperature. Combined with published vsin (i) results, our rotation period yields a 95% confidence lower limit of R{sub *} {>=} 0.111 R{sub Sun }, suggesting upper limits of 320 Myr and 0.055 M{sub Sun} on the age and mass. These limits should be regarded cautiously because of {approx}3{sigma} inconsistencies with other data; however, a lower limit of 45 Degree-Sign on the inclination is more secure. DENIS-P J1058.7-1548 is only the first of nearly two dozen low-amplitude variables discovered and analyzed by the Weather on Other Worlds project.

  3. Weather, Climate, and You.

    ERIC Educational Resources Information Center

    Blai, Boris, Jr.

    Information from the American Institute of Medical Climatologists on human responses to weather and climatic conditions, including clouds, winds, humidity, barometric pressure, heat, cold, and other variables that may exert a pervasive impact on health, behavior, disposition, and the level of efficiency with which individuals function is reviewed.…

  4. An assessment of the Polar Weather Research and Forecasting (WRF) model representation of near-surface meteorological variables over West Antarctica

    NASA Astrophysics Data System (ADS)

    Deb, Pranab; Orr, Andrew; Hosking, J. Scott; Phillips, Tony; Turner, John; Bannister, Daniel; Pope, James O.; Colwell, Steve

    2016-02-01

    Despite the recent significant climatic changes observed over West Antarctica, which include large warming in central West Antarctica and accelerated ice loss, adequate validation of regional simulations of meteorological variables are rare for this region. To address this gap, results from a recent version of the Polar Weather Research and Forecasting model (Polar WRF) covering West Antarctica at a high horizontal resolution of 5 km were validated against near-surface meteorological observations. The model employed physics options that included the Mellor-Yamada-Nakanishi-Niino boundary layer scheme, the WRF Single Moment 5-Class cloud microphysics scheme, the new version of the rapid radiative transfer model for both shortwave and longwave radiation, and the Noah land surface model. Our evaluation finds this model to be a useful tool for realistically capturing the near-surface meteorological conditions. It showed high skill in simulating surface pressure (correlation ≥0.97), good skill for wind speed with better correlation at inland sites (0.7-0.8) compared to coastal sites (0.3-0.6), generally good representation of strong wind events, and good skill for temperature in winter (correlation ≥0.8). The main shortcomings of this configuration of Polar WRF are an occasional failure to properly represent transient cyclones and their influence on coastal winds, an amplified diurnal temperature cycle in summer, and a general tendency to underestimate the wind speed at inland sites in summer. Additional sensitivity studies were performed to quantify the impact of the choice of boundary layer scheme and surface boundary conditions. It is shown that the model is most sensitive to the choice of boundary layer scheme, with the representation of the temperature diurnal cycle in summer significantly improved by selecting the Mellor-Yamada-Janjic boundary layer scheme. By contrast, the model results showed little sensitivity to whether the horizontal resolution was 5 or

  5. Weatherizing America

    ScienceCinema

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

    2013-05-29

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

  6. Weatherizing America

    SciTech Connect

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

    2009-01-01

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

  7. General circulation model results on migrating and nonmigrating tides in the mesosphere and lower thermosphere. Part I: comparison with observations

    NASA Astrophysics Data System (ADS)

    Grieger, Norbert; Volodin, Evgeny M.; Schmitz, Gerhard; Hoffmann, Peter; Manson, Alan H.; Fritts, David C.; Igarashi, Kiyoshi; Singer, Werner

    2002-05-01

    The general circulation model of the Department of Numerical Mathematics of the Russian Academy of Science (, Tellus 53A (2001) 300) from the surface to mesospheric and lower thermospheric heights has been used to analyse the diurnal and semi-diurnal tides. The GCM includes tropospheric and stratospheric tidal forcings due to absorption of the radiation and latent heat release and uses the gravity wave breaking parameterization of Hines (J. Atmos. Sol. Terr. Phys. 59 (1997a) 371; J. Atmos. Sol. Terr. Phys. 59 (1997b) 387). The model tides describe the observed tidal amplitudes and phases of eastward wind components at different northern hemispheric medium frequency radar sites (Andenes, Juliusruh, Saskatoon, Yamagawa and Hawaii) for January and July conditions. The separation of model tides into migrating and nonmigrating components shows that the nonmigrating part forms the total tide to a large extent, especially for the diurnal tide at low latitudes. The variability of diurnal and semi-diurnal tides is mostly determined by the variability of the nonmigrating part; the variability due to migrating tidal oscillations contributes only a small amount to the total variability. The nonmigrating diurnal model tide is strongly dependent on the longitude, with maxima in the western hemisphere at middle southern latitudes in January. In July, these tidal amplitudes are much weaker with maxima in the subtropics of the eastern hemisphere.

  8. River-tide dynamics: Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary

    NASA Astrophysics Data System (ADS)

    Guo, Leicheng; van der Wegen, Mick; Jay, David A.; Matte, Pascal; Wang, Zheng Bing; Roelvink, Dano; He, Qing

    2015-05-01

    River-tide dynamics remain poorly understood, in part because conventional harmonic analysis (HA) does not cope effectively with nonstationary signals. To explore nonstationary behavior of river tides and the modulation effects of river discharge, this work analyzes tidal signals in the Yangtze River estuary using both HA in a nonstationary mode and continuous wavelet transforms (CWT). The Yangtze is an excellent natural laboratory to analyze river tides because of its high and variable flow, its length, and the fact that there are do dams or reflecting barriers within the tidal part of the system. Analysis of tidal frequencies by CWT and analysis of subtidal water level and tidal ranges reveal a broad range of subtidal variations over fortnightly, monthly, semiannual, and annual frequencies driven by subtidal variations in friction and by variable river discharges. We employ HA in a nonstationary mode (NSHA) by segregating data within defined flow ranges into separate analyses. NSHA quantifies the decay of the principal tides and the modulation of M4 tide with increasing river discharges. M4 amplitudes decrease far upriver (landward portion of the estuary) and conversely increase close to the ocean as river discharge increases. The fortnightly frequencies reach an amplitude maximum upriver of that for over tide frequencies, due to the longer wavelength of the fortnightly constituents. These methods and findings should be applicable to large tidal rivers globally and have broad implications regarding management of navigation channels and ecosystems in tidal rivers.

  9. Public perceptions of Florida red tide risks.

    PubMed

    Kuhar, Sara E; Nierenberg, Kate; Kirkpatrick, Barbara; Tobin, Graham A

    2009-07-01

    This research integrates theoretical frameworks of risk perception, social amplification of risk, and the role of place-specific contexts in order to explore the various perceptions surrounding Florida red tides. Florida red tides are naturally occurring events that are increasing in frequency, duration, and severity. This has implications for public health, the local economy, and ecosystem health. While many of the negative impacts of Florida red tides are not easily controlled, some of the secondary impacts may be mitigated through individuals' responses. However, public perception and consequent reactions to Florida red tides have not been investigated. This research uses questionnaire surveys, and semi-structured interviews, to explore the various perceptions of the risk surrounding red tides. Surveys and interviews were conducted along two Florida west coast beaches. The results indicate that the underlying foundations of the social amplification of the risk framework are applicable to understanding how individuals form perceptions of risk relative to red tide events. There are key differences between the spatial locations of individuals and corresponding perceptions, indicating that place-specific contexts are essential to understanding how individuals receive and interpret risk information. The results also suggest that individuals may be lacking efficient and up-to-date information about Florida red tides and their impacts because of inconsistent public outreach. Overall, social and spatial factors appear to be influential as to whether individuals amplify or attenuate the risks associated with Florida red tides. PMID:19392675

  10. Public Perceptions of Florida Red Tide Risks

    PubMed Central

    Kuhar, Sara E.; Nierenberg, Kate; Kirkpatrick, Barbara; Tobin, Graham A.

    2009-01-01

    This research integrates theoretical frameworks of risk perception, social amplification of risk, and the role of place-specific contexts in order to explore the various perceptions surrounding Florida red tides. Florida red tides are naturally occurring events that are increasing in frequency, duration, and severity. This has implications for public health, the local economy, and ecosystem health. While many of the negative impacts of Florida red tides are not easily controlled, some of the secondary impacts may be mitigated through individuals’ responses. However, public perception and consequent reactions to Florida red tides have not been investigated. This research uses questionnaire surveys, and semi-structured interviews, to explore the various perceptions of the risk surrounding red tides. Surveys and interviews were conducted along two Florida west coast beaches. The results indicate that the underlying foundations of the social amplification of the risk framework are applicable to understanding how individuals form perceptions of risk relative to red tide events. There are key differences between the spatial locations of individuals and corresponding perceptions, indicating that place-specific contexts are essential to understanding how individuals receive and interpret risk information. The results also suggest that individuals may be lacking efficient and up-to-date information about Florida red tides and their impacts because of inconsistent public outreach. Overall, social and spatial factors appear to be influential as to whether individuals amplify or attenuate the risks associated with Florida red tides. PMID:19392675

  11. The Art of Red Tide Science

    PubMed Central

    Hall, Emily R.; Nierenberg, Kate; Boyes, Anamari J.; Heil, Cynthia A.; Flewelling, Leanne J.; Kirkpatrick, Barbara

    2012-01-01

    Over the years, numerous outreach strategies by the science community, such as FAQ cards and website information, have been used to explain blooms of the toxic dinoflagellate, Karenia brevis that occur annually off the west coast of Florida to the impacted communities. Many state and federal agencies have turned to funded research groups for assistance in the development and testing of environmental outreach products. In the case of Florida red tide, the Fish and Wildlife Research Institute/Mote Marine Laboratory (MML) Cooperative Red Tide Agreement allowed MML to initiate a project aimed at developing innovative outreach products about Florida red tide. This project, which we coined “The Art of Red Tide Science,” consisted of a team effort between scientists from MML and students from Ringling College of Art and Design. This successful outreach project focused on Florida red tide can be used as a model to develop similar outreach projects for equally complex ecological issues. PMID:22712002

  12. The Art of Red Tide Science.

    PubMed

    Hall, Emily R; Nierenberg, Kate; Boyes, Anamari J; Heil, Cynthia A; Flewelling, Leanne J; Kirkpatrick, Barbara

    2012-05-01

    Over the years, numerous outreach strategies by the science community, such as FAQ cards and website information, have been used to explain blooms of the toxic dinoflagellate, Karenia brevis that occur annually off the west coast of Florida to the impacted communities. Many state and federal agencies have turned to funded research groups for assistance in the development and testing of environmental outreach products. In the case of Florida red tide, the Fish and Wildlife Research Institute/Mote Marine Laboratory (MML) Cooperative Red Tide Agreement allowed MML to initiate a project aimed at developing innovative outreach products about Florida red tide. This project, which we coined "The Art of Red Tide Science," consisted of a team effort between scientists from MML and students from Ringling College of Art and Design. This successful outreach project focused on Florida red tide can be used as a model to develop similar outreach projects for equally complex ecological issues. PMID:22712002

  13. Atmospheric tides in Gale Crater, Mars

    NASA Astrophysics Data System (ADS)

    Guzewich, Scott D.; Newman, C. E.; de la Torre Juárez, M.; Wilson, R. J.; Lemmon, M.; Smith, M. D.; Kahanpää, H.; Harri, A.-M.

    2016-04-01

    Atmospheric tides are the primary source of daily air pressure variation at the surface of Mars. These tides are forced by solar heating of the atmosphere and modulated by the presence of atmospheric dust, topography, and surface albedo and thermal inertia. This results in a complex mix of sun-synchronous and non-sun-synchronous tides propagating both eastward and westward around the planet in periods that are integer fractions of a solar day. The Rover Environmental Monitoring Station on board the Mars Science Laboratory has observed air pressure at a regular cadence for over 1 Mars year and here we analyze and diagnose atmospheric tides in this pressure record. The diurnal tide amplitude varies from 26 to 63 Pa with an average phase of 0424 local true solar time, while the semidiurnal tide amplitude varies from 5 to 20 Pa with an average phase of 0929. We find that both the diurnal and semidiurnal tides in Gale Crater are highly correlated to atmospheric opacity variations at a value of 0.9 and to each other at a value of 0.77, with some key exceptions occurring during regional and local dust storms. We supplement our analysis with MarsWRF general circulation modeling to examine how a local dust storm impacts the diurnal tide in its vicinity. We find that both the diurnal tide amplitude enhancement and regional coverage of notable amplitude enhancement linearly scales with the size of the local dust storm. Our results provide the first long-term record of surface pressure tides near the martian equator.

  14. Bottom Pressure Tides Along a Line in the Southeast Atlantic Ocean and Comparisons with Satellite Altimetry

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Byrne, Deidre A.

    2010-01-01

    Seafloor pressure records, collected at 11 stations aligned along a single ground track of the Topex/Poseidon and Jason satellites, are analyzed for their tidal content. With very low background noise levels and approximately 27 months of high-quality records, tidal constituents can be estimated with unusually high precision. This includes many high-frequency lines up through the seventh-diurnal band. The station deployment provides a unique opportunity to compare with tides estimated from satellite altimetry, point by point along the satellite track, in a region of moderately high mesoscale variability. That variability can significantly corrupt altimeter-based tide estimates, even with 17 years of data. A method to improve the along-track altimeter estimates by correcting the data for nontidal variability is found to yield much better agreement with the bottom-pressure data. The technique should prove useful in certain demanding applications, such as altimetric studies of internal tides.

  15. Impact of tidal density variability on orbital and reentry predictions

    NASA Astrophysics Data System (ADS)

    Leonard, J. M.; Forbes, J. M.; Born, G. H.

    2012-12-01

    Since the first satellites entered Earth orbit in the late 1950's and early 1960's, the influences of solar and geomagnetic variability on the satellite drag environment have been studied, and parameterized in empirical density models with increasing sophistication. However, only within the past 5 years has the realization emerged that "troposphere weather" contributes significantly to the "space weather" of the thermosphere, especially during solar minimum conditions. Much of the attendant variability is attributable to upward-propagating solar tides excited by latent heating due to deep tropical convection, and solar radiation absorption primarily by water vapor and ozone in the stratosphere and mesosphere, respectively. We know that this tidal spectrum significantly modifies the orbital (>200 km) and reentry (60-150 km) drag environments, and that these tidal components induce longitude variability not yet emulated in empirical density models. Yet, current requirements for improvements in orbital prediction make clear that further refinements to density models are needed. In this paper, the operational consequences of longitude-dependent tides are quantitatively assessed through a series of orbital and reentry predictions. We find that in-track prediction differences incurred by tidal effects are typically of order 200 ± 100 m for satellites in 400-km circular orbits and 15 ± 10 km for satellites in 200-km circular orbits for a 24-hour prediction. For an initial 200-km circular orbit, surface impact differences of order 15° ± 15° latitude are incurred. For operational problems with similar accuracy needs, a density model that includes a climatological representation of longitude-dependent tides should significantly reduce errors due to this source.

  16. North Atlantic Climate Variability: Preliminary Analysis of Historical Weather Data and Stable Isotope Time Series of Cave Dripwater and Holocene-Age Stalagmites from Bermuda

    NASA Astrophysics Data System (ADS)

    Gaurin, S. E.; Burns, S. J.; Woodworth, M.; Wood, J.; Edwards, L.; Cheng, H.

    2008-12-01

    Bermuda, located in the center of the Sargasso Sea of the North Atlantic Ocean, is a unique laboratory for analyzing Holocene climate change. This subtropical area lacks a strong seasonal cycle, making it an ideal place to look for low-frequency cycles identified in observational records of North Atlantic climate. A preliminary statistical analysis of historical climate data, provided by the Bermuda Weather Service and spanning a period from 1852 to 2006, will be presented. Emphasis will be placed on the identification of cycles corresponding to such climate modes as the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation (AMO). To extend the record back farther than the observational period, it is necessary to identify and analyze paleoclimate proxies. Carbonate caves on the island of Bermuda contain numerous speleothems, which have the potential to serve as extremely high-resolution (sub-decadal) recorders of climate change via the stable oxygen and carbon isotope concentrations contained in their crystalline form. Stalagmite stable isotope data is reflective of changes in stable isotopes of the cave dripwater feeding the stalagmite. Approximately monthly time series of δ18O data from three dripwater sites in each of two Bermuda caves, Fantasy Cave and Leamington Cave, will be presented, covering the period from April 2006 to March 2008. Values from Fantasy Cave range from -4.7 permil to -3.0 permil. Interestingly, a positive excursion of ~0.8 permil in the dripwater δ18O is associated with the passage of Hurricane Florence over the island in September 2006; possible causes of this spike include a change in vapor source or hurricane wind-induced sea spray. The dripwater data will help us to calibrate and interpret the stable isotope data from stalagmite calcite in our samples. Several stalagmites retrieved from caves in the Hamilton Parish region of Bermuda were dated by U-series methods and found to cover a period from 4.7 thousand years

  17. Pole tide in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Medvedev, I. P.; Rabinovich, A. B.; Kulikov, E. A.

    2014-03-01

    The pole tide, which is driven by the Chandler Wobble, has a period of about 14 months and typical amplitudes in the World Ocean of ˜0.5 cm. However, in the Baltic Sea the pole tide is anomalously high. To examine this effect we used long-term hourly sea level records from 23 tide gauges and monthly records from 64 stations. The lengths of the series were up to 123 years for hourly records and 211 years for monthly records. High-resolution spectra revealed a cluster of neighboring peaks with periods from 410 to 440 days. The results of spectral analysis were applied to estimate the integral amplitudes of pole tides from all available tide gauges along the coast of the Baltic Sea. The height of the pole tide was found to gradually increase from the entrance (Danish Straits, 1.5-2 cm) to the northeast end of the sea. The largest amplitudes—up to 4.5-7 cm—were observed in the heads of the Gulf of Finland and the Gulf of Bothnia. Significant temporal fluctuations in amplitudes and periods of the pole tide were observed during the 19th and 20th centuries.

  18. The Variability and Intermittency of Wind and Solar Power Can Be Overcome Without Storage By Using the National Energy With Weather System (NEWS) Simulator To Design A National US Electric (and Energy) Sector

    NASA Astrophysics Data System (ADS)

    Clack, C.; MacDonald, A. E.; Wilczak, J. M.; Alexander, A.; Dunbar, A. D.; Xie, Y.; Picciano, P.; Paine, J.; Terry, L.; Marquis, M.

    2015-12-01

    The importance of weather-driven renewable energies for the United States energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs. The Cooperative Institute for the Research in Environmental Sciences at the University of Colorado collaborated with the Earth Systems Research Laboratory of the National Oceanic and Atmospheric Administration to construct a mathematical optimization of a reduced form of the US electric sector. Care was taken to retain salient features of the electric sector, while allowing for detailed weather and power data to be incorporated for wind and solar energies. The National Energy with Weather System (NEWS) simulator was created. With the NEWS simulator tests can be performed that are unique and insightful. The simulator can maintain the status quo and build out a system following costs or imposed targets for carbon dioxide emission reductions. It can find the least cost electric sector for each state, or find a national power system that incorporates vast amounts of variable generation. In the current presentation, we will focus on one of the most unique aspects of the NEWS simulator; the ability to specify a specific amount of wind and/or solar each hour for a three-year historical period for the least total cost. The simulator can find where to place wind and solar to reduce variability (ramping requirements for back-up generators). The amount of variable generation each hour is very different to an RPS type standard because the generators need to work in concert for long periods of time. The results indicate that for very similar costs the amount of back-up generation (natural gas or storage) can be reduced significantly.

  19. Florida Red Tide Perception: Residents versus Tourists

    PubMed Central

    Nierenberg, Kate; Byrne, Margaret; Fleming, Lora E.; Stephan, Wendy; Reich, Andrew; Backer, Lorraine C.; Tanga, Elvira; Dalpra, Dana R.; Kirkpatrick, Barbara

    2010-01-01

    The west coast of Florida has annual blooms of the toxin-producing dinoflagellate, Karenia brevis with Sarasota, FL considered the epicenter for these blooms. Numerous outreach materials, including Frequently Asked Question (FAQ) cards, exhibits for local museums and aquaria, public beach signs, and numerous websites have been developed to disseminate information to the public about this natural hazard. In addition, during intense onshore blooms, a great deal of media attention, primarily via newspaper (print and web) and television, is focused on red tide. However to date, the only measure of effectiveness of these outreach methods has been counts of the number of people exposed to the information, e.g., visits to a website or number of FAQ cards distributed. No formal assessment has been conducted to determine if these materials meet their goal of informing the public about Florida red tide. Also, although local residents have the opinion that they are very knowledgeable about Florida red tide, this has not been verified empirically. This study addressed these issues by creating and administering an evaluation tool for the assessment of public knowledge about Florida red tide. A focus group of Florida red tide outreach developers assisted in the creation of the evaluation tool. The location of the evaluation was the west coast of Florida, in Sarasota County. The objective was to assess the knowledge of the general public about Florida red tide. This assessment identified gaps in public knowledge regarding Florida red tides and also identified what information sources people want to use to obtain information on Florida red tide. The results from this study can be used to develop more effective outreach materials on Florida red tide. PMID:20824108

  20. Dissipation and Synchronization due to Creeping Tides.

    NASA Astrophysics Data System (ADS)

    Ferraz-Mello, Sylvio

    2012-05-01

    We present a new reophysical theory of the dynamical tides of celestial bodies. It is founded on a Newtonian creep instead of the classical delayed elastic approach of the standard viscoelastic theories. All results of the theory derive from the solution of a non-homogeneous ordinary differential equation and lags appear as a natural outcome from the solution of the equation and are not external ad hoc quantities plugged in an elastic model. The lag due to the Newtonian creep is proportional to the tide frequency (as in Darwin’s original theory), and is necessarily small. The amplitudes depend on the viscosity of the body and on the frequency of the tide. As a consequence, the so-called pseudo-synchronous rotation has an excess velocity roughly proportional to 6ne2/(χ2+1/χ2) (χ is the tide frequency in units of a relaxation factor inversely proportional to the viscosity) instead of the exact 6ne2 of standard theories. The dissipation is inversely proportional to (χ + 1/χ) thus, in the inviscid limit it is roughly proportional to the frequency (as in standard theories), but that behavior is inverted when the viscosity is high and the response factor much smaller than the tide frequency. When the viscosity is high, however, the creeping tide fails to reproduce the actual geometric tide and, to reconcile theory and observation, we need to assume the coexistence of a small elastic tide superposed to the creeping tide. The theory is applied to several Solar System and extrasolar bodies and the values of the relaxation factor μ (and its current correspondent Q) are derived for these bodies on the basis of currently available data.

  1. Florida Red Tide Perception: Residents versus Tourists.

    PubMed

    Nierenberg, Kate; Byrne, Margaret; Fleming, Lora E; Stephan, Wendy; Reich, Andrew; Backer, Lorraine C; Tanga, Elvira; Dalpra, Dana R; Kirkpatrick, Barbara

    2010-09-01

    The west coast of Florida has annual blooms of the toxin-producing dinoflagellate, Karenia brevis with Sarasota, FL considered the epicenter for these blooms. Numerous outreach materials, including Frequently Asked Question (FAQ) cards, exhibits for local museums and aquaria, public beach signs, and numerous websites have been developed to disseminate information to the public about this natural hazard. In addition, during intense onshore blooms, a great deal of media attention, primarily via newspaper (print and web) and television, is focused on red tide. However to date, the only measure of effectiveness of these outreach methods has been counts of the number of people exposed to the information, e.g., visits to a website or number of FAQ cards distributed. No formal assessment has been conducted to determine if these materials meet their goal of informing the public about Florida red tide. Also, although local residents have the opinion that they are very knowledgeable about Florida red tide, this has not been verified empirically. This study addressed these issues by creating and administering an evaluation tool for the assessment of public knowledge about Florida red tide. A focus group of Florida red tide outreach developers assisted in the creation of the evaluation tool. The location of the evaluation was the west coast of Florida, in Sarasota County. The objective was to assess the knowledge of the general public about Florida red tide. This assessment identified gaps in public knowledge regarding Florida red tides and also identified what information sources people want to use to obtain information on Florida red tide. The results from this study can be used to develop more effective outreach materials on Florida red tide. PMID:20824108

  2. The Global S_1 Tide in Earth's Nutation

    NASA Astrophysics Data System (ADS)

    Schindelegger, Michael; Einšpigel, David; Salstein, David; Böhm, Johannes

    2016-05-01

    Diurnal S_1 tidal oscillations in the coupled atmosphere-ocean system induce small perturbations of Earth's prograde annual nutation, but matching geophysical model estimates of this Sun-synchronous rotation signal with the observed effect in geodetic Very Long Baseline Interferometry (VLBI) data has thus far been elusive. The present study assesses the problem from a geophysical model perspective, using four modern-day atmospheric assimilation systems and a consistently forced barotropic ocean model that dissipates its energy excess in the global abyssal ocean through a parameterized tidal conversion scheme. The use of contemporary meteorological data does, however, not guarantee accurate nutation estimates per se; two of the probed datasets produce atmosphere-ocean-driven S_1 terms that deviate by more than 30 μ as (microarcseconds) from the VLBI-observed harmonic of -16.2+i113.4 μ as. Partial deficiencies of these models in the diurnal band are also borne out by a validation of the air pressure tide against barometric in situ estimates as well as comparisons of simulated sea surface elevations with a global network of S_1 tide gauge determinations. Credence is lent to the global S_1 tide derived from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and the operational model of the European Centre for Medium-Range Weather Forecasts (ECMWF). When averaged over a temporal range of 2004 to 2013, their nutation contributions are estimated to be -8.0+i106.0 μ as (MERRA) and -9.4+i121.8 μ as (ECMWF operational), thus being virtually equivalent with the VLBI estimate. This remarkably close agreement will likely aid forthcoming nutation theories in their unambiguous a priori account of Earth's prograde annual celestial motion.

  3. Weather from the Stratosphere?

    NASA Technical Reports Server (NTRS)

    Baldwin, Mark P.; Thompson, David W. J.; Shuckburgh, Emily F.; Norton, Warwick A.; Gillett, Nathan P.

    2006-01-01

    Is the stratosphere, the atmospheric layer between about 10 and 50 km, important for predicting changes in weather and climate? The traditional view is that the stratosphere is a passive recipient of energy and waves from weather systems in the underlying troposphere, but recent evidence suggests otherwise. At a workshop in Whistler, British Columbia (1), scientists met to discuss how the stratosphere responds to forcing from below, initiating feedback processes that in turn alter weather patterns in the troposphere. The lowest layer of the atmosphere, the troposphere, is highly dynamic and rich in water vapor, clouds, and weather. The stratosphere above it is less dense and less turbulent (see the figure). Variability in the stratosphere is dominated by hemispheric-scale changes in airflow on time scales of a week to several months. Occasionally, however, stratospheric air flow changes dramatically within just a day or two, with large-scale jumps in temperature of 20 K or more. The troposphere influences the stratosphere mainly through atmospheric waves that propagate upward. Recent evidence shows that the stratosphere organizes this chaotic wave forcing from below to create long-lived changes in the stratospheric circulation. These stratospheric changes can feed back to affect weather and climate in the troposphere.

  4. Possible forcing of global temperature by the oceanic tides

    PubMed Central

    Keeling, Charles D.; Whorf, Timothy P.

    1997-01-01

    An approximately decadal periodicity in surface air temperature is discernable in global observations from A.D. 1855 to 1900 and since A.D. 1945, but with a periodicity of only about 6 years during the intervening period. Changes in solar irradiance related to the sunspot cycle have been proposed to account for the former, but cannot account for the latter. To explain both by a single mechanism, we propose that extreme oceanic tides may produce changes in sea surface temperature at repeat periods, which alternate between approximately one-third and one-half of the lunar nodal cycle of 18.6 years. These alternations, recurring at nearly 90-year intervals, reflect varying slight degrees of misalignment and departures from the closest approach of the Earth with the Moon and Sun at times of extreme tide raising forces. Strong forcing, consistent with observed temperature periodicities, occurred at 9-year intervals close to perihelion (solar perigee) for several decades centered on A.D. 1881 and 1974, but at 6-year intervals for several decades centered on A.D. 1923. As a physical explanation for tidal forcing of temperature we propose that the dissipation of extreme tides increases vertical mixing of sea water, thereby causing episodic cooling near the sea surface. If this mechanism correctly explains near-decadal temperature periodicities, it may also apply to variability in temperature and climate on other times-scales, even millennial and longer. PMID:11607740

  5. Nordic Sea Level - Analysis of PSMSL RLR Tide Gauge data

    NASA Astrophysics Data System (ADS)

    Knudsen, Per; Andersen, Ole

    2015-04-01

    Tide gauge data from the Nordic region covering a period of time from 1920 to 2000 are evaluated. 63 stations having RLR data for at least 40 years have been used. Each tide gauge data record was averaged to annual averages after the monthly average seasonal anomalies were removed. Some stations lack data, especially before around 1950. Hence, to compute representative sea level trends for the 1920-2000 period a procedure for filling in estimated sea level values in the voids, is needed. To fill in voids in the tide gauge data records a reconstruction method was applied that utilizes EOF.s in an iterative manner. Subsequently the trends were computed. The estimated trends range from about -8 mm/year to 2 mm/year reflecting both post-glacial uplift and sea level rise. An evaluation of the first EOFs show that the first EOF clearly describes the trends in the time series. EOF #2 and #3 describe differences in the inter-annual sea level variability with-in the Baltic Sea and differences between the Baltic and the North Atlantic / Norwegian seas, respectively.

  6. Stratospheric sudden warming and lunar tide

    NASA Astrophysics Data System (ADS)

    Yamazaki, Yosuke; Kosch, Michael

    2016-07-01

    A stratospheric sudden warming is a large-scale disturbance in the middle atmosphere. Recent studies have shown that the effect of stratospheric sudden warnings extends well into the upper atmosphere. A stratospheric sudden warming is often accompanied by an amplification of lunar tides in the ionosphere/theremosphere. However, there are occasionally winters when a stratospheric sudden warming occurs without an enhancement of the lunar tide in the upper atmosphere, and other winters when large lunar tides are observed without a strong stratospheric sudden warming. We examine the winters when the correlation breaks down and discuss possible causes.

  7. Diurnal tides in the Arctic Ocean

    NASA Technical Reports Server (NTRS)

    Kowalik, Z.; Proshutinsky, A. Y.

    1993-01-01

    A 2D numerical model with a space grid of about 14 km is applied to calculate diurnal tidal constituents K(1) and O(1) in the Arctic Ocean. Calculated corange and cotidal charts show that along the continental slope, local regions of increased sea level amplitude, highly variable phase and enhanced currents occur. It is shown that in these local regions, shelf waves (topographic waves) of tidal origin are generated. In the Arctic Ocean and Northern Atlantic Ocean more than 30 regions of enhanced currents are identified. To prove the near-resonant interaction of the diurnal tides with the local bottom topography, the natural periods of oscillations for all regions have been calculated. The flux of energy averaged over the tidal period depicts the gyres of semitrapped energy, suggesting that the shelf waves are partially trapped over the irregularities of the bottom topography. It is shown that the occurrence of near-resonance phenomenon changes the energy flow in the tidal waves. First, the flux of energy from the astronomical sources is amplified in the shelf wave regions, and afterwards the tidal energy is strongly dissipated in the same regions.

  8. Validation of ocean tide models around Antarctica using onshore GPS and gravity data

    NASA Astrophysics Data System (ADS)

    King, M. A.; Penna, N. T.; Clarke, P. J.; Thomas, I.

    2005-12-01

    Ocean tide modeling errors, along with subsequent ocean tide loading (OTL) displacement modeling errors, alias into altimetry and time variable gravity (e.g., GRACE) time series. Present ocean tide models around Antarctica are shown to disagree by up to several decimeters per constituent, especially in the large ice shelf regions, and are presently only sparsely tested against independent data. In terms of modeled OTL displacements, the inter-model disagreements are of the order of a few millimeters or less per constituent and hence high quality geodetic measurements are able to rank relative model accuracy. To achieve this for the circum-Antarctic seas, GPS data from fifteen sites have been used to derive three-dimensional displacement estimates at eight diurnal and semidiurnal tidal frequencies. These are then compared with OTL displacement estimates derived from global and regional ocean tide models. Modeled tidal gravity variations are also compared with gravity measurements at the South Pole. In East Antarctica, where the tides are well-defined, sub-millimeter differences are demonstrated in each coordinate component with the lunar N2 and Q1 constituents in closest agreement. In West Antarctica, where sites are nearer the largest ice shelves, agreement with the older models (CSR3 and TPXO.2) and NAO.99b is poor for all constituents. Overall the GPS and gravity data agree best with newer tide models, such as TPXO.6.2, but further data are required to validate the models at the most remote locations.

  9. Bottom friction optimization for a better barotropic tide modelling

    NASA Astrophysics Data System (ADS)

    Boutet, Martial; Lathuilière, Cyril; Son Hoang, Hong; Baraille, Rémy

    2015-04-01

    At a regional scale, barotropic tides are the dominant source of variability of currents and water heights. A precise representation of these processes is essential because of their great impacts on human activities (submersion risks, marine renewable energies, ...). Identified sources of error for tide modelling at a regional scale are the followings: bathymetry, boundary forcing and dissipation due to bottom friction. Nevertheless, bathymetric databases are nowadays known with a good accuracy, especially over shelves, and global tide models performances are better than ever. The most promising improvement is thus the bottom friction representation. The method used to estimate bottom friction is the simultaneous perturbation stochastic approximation (SPSA) which consists in the approximation of the gradient based on a fixed number of cost function measurements, regardless of the dimension of the vector to be estimated. Indeed, each cost function measurement is obtained by randomly perturbing every component of the parameter vector. An important feature of SPSA is its relative ease of implementation. In particular, the method does not require the development of tangent linear and adjoint version of the circulation model. Experiments are carried out to estimate bottom friction with the HYbrid Coordinate Ocean Model (HYCOM) in barotropic mode (one isopycnal layer). The study area is the Northeastern Atlantic margin which is characterized by strong currents and an intense dissipation. Bottom friction is parameterized with a quadratic term and friction coefficient is computed with the water height and the bottom roughness. The latter parameter is the one to be estimated. Assimilated data are the available tide gauge observations. First, the bottom roughness is estimated taking into account bottom sediment natures and bathymetric ranges. Then, it is estimated with geographical degrees of freedom. Finally, the impact of the estimation of a mixed quadratic/linear friction

  10. [Red tides in México: a review].

    PubMed

    Cortés-Altamirano, R; Hernández-Becerril, D U; Luna-Soria, R

    1995-01-01

    With the purpose to make a review on the red tides occurence at mexican coasts, previous studies were analyzed. Dinoflagellates seem to be the main cause of toxic events mainly Gonyaulax polygramma, Gymnodinium catenatum, Pyrodinium bahamense var. compressum and Ptychodiscus brevis. There are other species which cause red tides but are not toxic. They are: Mesodinium rubrum, Gonyaulax triacantha, Noctiluca scintillans, Prorocentrum dentatum, Gymnodinium splendens, G. sanguineum, Ceratium tripos var. ponticum, C. furca, Scrippsiella trocoidea and Oscillatoria erythraea. The first of these is the most common cilliate of the Pacific coastlines and the last one is the most common cyanophyceae during the strong events of "El Niño". The magnitude is quite variable, from small stains of a hundred square meters to several square kilometers and its density ranges from 0.5 to 36 million cells/l. Their residence time goes from 1 or 2 days to as long as 5 months. The great densities are due to Prorocentrum dentatum and P. minimum, the latter is only observed in estuarine ponds for shrimp cultivation, they have not been related to poisoning episodes. New areas of the red tide occurrence have been recorded during the last decades, such as Acapulco Bay, Huatulco, Salinacruz and Puerto Madero. These localities and also Mazatlán, are the only regions in which paralytic shellfish poisoning (PSP) have registered fatal cases and in the Gulf of Mexico a great mortality of fishes has been noted due to ictiotoxin produced by Ptychodiscus brevis. On the other hand, at Yucatan and west coast of the Peninsula of California red tide events are little known. PMID:8900570

  11. Investigations in Marine Chemistry: Tide Pool Ecology.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.

    Students investigated the salinity of tide pools at different levels in the intertidal zone. Data are analyzed collectively. Students graphed and discussed data. Included are suggestions for evaluation and further study. (Author)

  12. The Tides--A Neglected Topic.

    ERIC Educational Resources Information Center

    Hartel, Hermann

    2000-01-01

    Finds that computer simulations can be used to visualize the processes involved with lunar tides. Technology adds value, thus opening new paths for a more distinct analysis and increased learning results. (Author/CCM)

  13. Preliminary Study on Coupling Wave-Tide-Storm Surges Prediction System

    NASA Astrophysics Data System (ADS)

    You, S.; Park, S.; Seo, J.; Kim, K.

    2008-12-01

    The Korean Peninsula is surrounded by the Yellow Sea, East China Sea, and East Sea. This complex oceanographic system includes large tides in the Yellow Sea and seasonally varying monsoon and typhoon events. For Korea's coastal regions, floods caused by wave and storm surges are among the most serious threats. To predict more accurate wave and storm surge, the development of coupling wave-tide-storm surges prediction system is essential. For the time being, wave and storm surges predictions are still made separately in KMA (Korea Meteorological Administration) and most operational institute. However, many researchers have emphasized the effects of tides and storm surges on wind waves and recommended further investigations into the effects of wave-tide-storm surges interactions and coupling module on wave heights. However, tidal height and current give a great effect on the wave prediction in the Yellow sea where is very high tide and related research is not enough. At present, KMA has operated the wave (RWAM : Regional Wave Model) and storm surges/tide prediction system (RTSM : Regional Tide/Storm Surges Model) for ocean forecasting. The RWAM is WAVEWATCH III which is a third generation wave model developed by Tolman (1989). The RTSM is based on POM (Princeton Ocean Model, Blumberg and Mellor, 1987). The RWAM and RTSM cover the northwestern Pacific Ocean from 115°E to 150°E and from 20°N to 52°N. The horizontal grid intervals are 1/12° in both latitudinal and longitudinal directions. The development, testing and application of a coupling module in which wave-tide-storm surges are incorporated within the frame of KMA Ocean prediction system, has been considered as a step forward in respect of ocean forecasting. In addition, advanced wave prediction model will be applicable to the effect of ocean in the weather forecasting system. The main purpose of this study is to show how the coupling module developed and to report on a series of experiments dealing with the

  14. Using Tide Data in Introductory Classes

    NASA Astrophysics Data System (ADS)

    de Jong, Marvin L.

    2006-11-01

    Ocean tides are not typically high in our consciousness here in Missouri, but in teaching astronomy and physical science the subject always comes up, and teachers of physical science and astronomy are all quite familiar with the textbook explanations. Our goal here is not to explain tides1,2 but to make some suggestions about how, on their own, students can discover relationships between hypotheses and actual evidence.

  15. Mapping Hurricane Rita inland storm tide

    USGS Publications Warehouse

    Berenbrock, Charles; Mason, Jr., Robert R.; Blanchard, Stephen F.

    2009-01-01

    Flood-inundation data are most useful for decision makers when presented in the context of maps of effected communities and (or) areas. But because the data are scarce and rarely cover the full extent of the flooding, interpolation and extrapolation of the information are needed. Many geographic information systems (GIS) provide various interpolation tools, but these tools often ignore the effects of the topographic and hydraulic features that influence flooding. A barrier mapping method was developed to improve maps of storm tide produced by Hurricane Rita. Maps were developed for the maximum storm tide and at 3-hour intervals from midnight (0000 hour) through noon (1200 hour) on September 24, 2005. The improved maps depict storm-tide elevations and the extent of flooding. The extent of storm-tide inundation from the improved maximum storm-tide map was compared to the extent of flood-inundation from a map prepared by the Federal Emergency Management Agency (FEMA). The boundaries from these two maps generally compared quite well especially along the Calcasieu River. Also a cross-section profile that parallels the Louisiana coast was developed from the maximum storm-tide map and included FEMA high-water marks.

  16. Mapping hurricane rita inland storm tide

    USGS Publications Warehouse

    Berenbrock, C.; Mason, R.R., Jr.; Blanchard, S.F.

    2009-01-01

    Flood-inundation data are most useful for decision makers when presented in the context of maps of affected communities and (or) areas. But because the data are scarce and rarely cover the full extent of the flooding, interpolation and extrapolation of the information are needed. Many geographic information systems provide various interpolation tools, but these tools often ignore the effects of the topographic and hydraulic features that influence flooding. A barrier mapping method was developed to improve maps of storm tide produced by Hurricane Rita. Maps were developed for the maximum storm tide and at 3-h intervals from midnight (00:00 hours) through noon (12:00 hours) on 24 September 2005. The improved maps depict storm-tide elevations and the extent of flooding. The extent of storm-tide inundation from the improved maximum storm-tide map was compared with the extent of flood inundation from a map prepared by the Federal Emergency Management Agency (FEMA). The boundaries from these two maps generally compared quite well especially along the Calcasieu River. Also a cross-section profile that parallels the Louisiana coast was developed from the maximum storm-tide map and included FEMA high-water marks. ?? 2009 Blackwell Publishing Ltd.

  17. Weather control

    SciTech Connect

    Leepson, M.

    1980-09-05

    Weather modification, the intentional altering of atmospheric conditions to suit the purposes of humankind, has five basic forms: (1) fog dissipation; (2) rain and snow enhancement; (3) hail suppression; (4) lightning suppression; and (5) the abatement of severe storms such as hurricanes and tornadoes. The dissipation of fog and the seeding of clouds with dry ice or silver iodide to produce rain are the most successful weather modification techniques. Both are used extensively and with varying degrees of success in the United States and around the world. Cloud seeding, though, is not effective in easing the harshness of a drought, such as the one that hit the Southwest, Midwest and Great Plains this summer.

  18. QBO Generated Inter-annual Variations of the Diurnal Tide in the Mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, Hans G.; Mengel, John G.

    2004-01-01

    We report results from a study with the Numerical Spectral Model (NSM), which produces in the mesosphere significant inter-annual variations in the diurnal tide. Applying Hines Doppler Spread Parameterization (DPS), small-scale gravity waves (GW) drive the Quasi-biennial Oscillation (QBO) and Semi-annual Oscillation (SAO). With a GW source that peaks at the equator and is taken to be isotropic and independent of season, the NSM generates near the equator a QBO with variable periods around 27 months and zonal wind amplitudes close to 20 m / s at 30 Ism. As reported earlier, the NSM reproduces the observed equinoctial maxima in the diurnal tide at altitudes around 95 km. In the present paper it is shown that the QBO modulates the tide such that the seasonal amplitude maxima can vary from one year to another by as much as 30%. Since the period of the QBO is variable, its phase relative to the seasonal cycle changes. The magnitude of the QBO modulation of the tide thus varies considerably as our long-term model simulation shows. To shed light on the underlying mechanism, the relative importance of the linearized advection terms are discussed that involve the meridional and vertical winds of the diurnal tide.

  19. QBO Generated Inter-annual Variations of the Diurnal Tide in the Mesosphere

    NASA Technical Reports Server (NTRS)

    Mayr, Hans G.; Mengel, John G.

    2004-01-01

    We report results from a study with the Numerical Spectral Model (NSM), which produces in the d i d tide significant inter-annual variations. Applying Hines' Doppler Spread Parameterization (DPS), small-scale gravity waves (GW) drive the Quasi-biennial Oscillation (QBO) and Semi-annual Oscillation (SAO). With a GW source that peaks at the equator and is taken to be isotropic and independent of season, the NSM generates a QBO with variable periods around 27 months and zonal wind amplitudes close to 20 m/s at 30 lan, As reported earlier, the NSM reproduces the observed equinoctial maxima in the diurnal tide at altitudes around 95 km. In the present paper it is shown that the QBO modulates the tide such that the seasonal amplitude maxima can vary from one year to another by as much as 30%. Since the period of the QBO is variable, its phase relative to the seasonal cycle changes. The magnitude of the QBO modulation of the tide thus varies considerably as our long-term model simulation shows. To shed light on the underlying mechanisms, we discuss (a) the relative importance of the linearized advection terms that involve the meridional and vertical winds of the diurnal tide and (b) the effects momentum deposition from GWs filtered by the QBO.

  20. Temporal variations of groundwater salinity and temperature in a tidal flat in front of a tide pool

    NASA Astrophysics Data System (ADS)

    Nakashita, Shinya; Hibino, Tadashi; Komai, Katsuaki; Narong, Touch

    2016-07-01

    A tidal flat in an estuary is a complex hydrological system, which is characterized by interactions between surface water in river and groundwater and is particularly driven by tides. Small-scale variability in the discharge or inflow could lead to variable results of surface groundwater salinity and temperature. In particular, there is a high possibility that a hydraulic head difference due to the presence of a tide pool, lagoon, or seep would cause the generation of small-scale spatial submarine groundwater discharge. This study investigates the spatio-temporal variations in surface groundwater salinity and temperature (0-50 cm depth) and the groundwater table in a tidal flat in the presence and absence of a tide pool. A tide pool formed in the Ota River diversion channel at the study observation site following the construction of a masonry revetment in the intertidal zone. We established observation sites at three locations to consider the effects of the presence or absence of a tide pool. Specifically, we measured the surface water in river and groundwater salinity, temperature, and level in the presence and absence of a tide pool in 2007 and 2009. Reviewing the past data based on these results, we found the characteristic variation of groundwater salinity around the tide pool during flood event in 2004. Groundwater salinity and temperature were directly measured by setting conductivity-temperature meters in the tidal flat. We conclude that the groundwater table in the presence of the tide pool was 20 cm higher than in areas where no tide pool existed. The temporal variation of groundwater salinity in the presence of the tide pool was 5 psu lower than those where a tide pool was absent. Moreover, we confirmed the increase in groundwater salinity up to 8 psu in the tidal flat during flood, when river water salinity was at 0 psu and groundwater salinity in the tide pool was at 10 psu. We consider that the high groundwater table, the low salinity, and the increase

  1. Temperature tides determined with meteor radar

    NASA Astrophysics Data System (ADS)

    Hocking, W. K.; Hocking, A.

    2002-09-01

    A new analysis method for producing tidal temperature parameters using meteor radar measurements is presented, and is demonstrated with data from one polar and two mid-latitude sites. The technique further develops the temperature algorithm originally introduced by Hocking (1999). That earlier method was used to produce temperature measurements over time scales of days and months, but required an empirical model for the mean temperature gradient in the mesopause region. However, when tides are present, this temperature gradient is modulated by the presence of the tides, complicating extraction of diurnal variations. Nevertheless, if the vertical wavelengths of the tides are known from wind measurements, the effects of the gradient variations can be compensated for, permitting determination of temperature tidal amplitudes and phases by meteor techniques. The basic theory is described, and results from meteor radars at Resolute Bay (Canada), London (Canada) and Albuquerque (New Mexico, USA) are shown. Our results are compared with other lidar data, computer models, fundamental tidal theory and rocket data. Phase measurements at two mid-latitude sites (Albuquerque, New Mexico, and London, Canada) show times of maximum for the diurnal temperature tide to change modestly throughout most of the year, varying generally between 0 h and 6 h, with an excursion to 12 h in June at London. The semidiurnal tide shows a larger annual variation in time of maximum, being at 2 4 h in the winter months but increasing to 9 h during the late summer and early fall. We also find that, at least at mid-latitudes, the phase of the temperature tide matches closely the phase of the meridional tide, and theoretical justification for this statement is given. We also demonstrate that this is true using the Global Scale Wave Model (Hagan et al., 1999). Median values for the temperature amplitudes for each site are in the range 5 to 6 Kelvin. Results from a more northern site (Resolute Bay) show

  2. Wind Forcing of the North Sea Pole Tide

    NASA Technical Reports Server (NTRS)

    OConnor, W.; Chao, B. F.; Zheng, D. W.; Au, Z. Y.

    1998-01-01

    The Chandler wobble of the earth's rotation has a period near 14 months and sets up the 0.5 cm amplitude pole tide in the deep oceans, However, the pole tide is anomalously large in the North Sea, where the amplitude increases sharply up to 3 cm along the continental coast. It is shown here that the sea levels are well correlated with winds at the pole tide frequency. The Princeton Ocean Model is used to investigate the response of the North Sea to wind forcing. The barotropic numerical ocean model depicts realistic coastlines and bathymetry at 5 ft x 5 ft resolution, with 97 x 73 grid points. The monthly mean wind fields for the 40-year period (1958-1997) from the National Centers for Atmospheric Prediction (NCEP) reanalysis were used to force the model. The winds were converted to stress with a neutral drag coefficient that varied linearly with windspeed (instead of using the NCEP windstress). A 5-day simulation was made for each month until the resulting flow regime came into equilibrium, and model water levels at various station locations were saved for comparison with tidal-gauge observed sea levels from the Permanent Service for Mean Sea Level (PSMSL). The comparison is made for 10 North Sea stations with high quality tide gauge data. We find: (1) good agreement in annual and semi-annual phases and in the trend of amplitude w.r.t. latitude; (2) more importantly for this study, the model-predicted and observed non-seasonal sea level variations show a very significant temporal correlation as well as spectral coherence. However, a large amplitude difference exists between the two sets -- the overall amplitude variability of the observed is generally a factor of 2-3 larger than the model prediction (this same phenomenon has been reported in ocean circulation studies, although the cause is not yet clear.) Our results indicate that the wind forcing is the main cause of the observed large pole tide in the North Sea.

  3. National Weather Service

    MedlinePlus

    ... Lightning Safe Boating Rip Currents Thunderstorms and Tornadoes Space Weather Sun (Ultraviolet Radiation) Safety Campaigns Wind Drought ... Outlook Hurricanes Fire Weather Outlooks UV Alerts Drought Space Weather NOAA Weather Radio NWS CAP Feeds PAST ...

  4. The Application of Synoptic Weather Forecasting Rules to Selected Weather Situations in the United States.

    ERIC Educational Resources Information Center

    Kohler, Fred E.

    The document describes the use of weather maps and data in teaching introductory college courses in synoptic meteorology. Students examine weather changes at three-hour intervals from data obtained from the "Monthly Summary of Local Climatological Data." Weather variables in the local summary include sky cover, air temperature, dew point, relative…

  5. Random, but Uniform Please: Requirements for Synthetic Weather Generation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synthetic weather generation models often rely on standard uniform random numbers (RN) to simulate stochastic aspects of weather. However, short sequences of RNs, needed to generate certain weather variables, are not necessarily uniformly distributed, as assumed by weather generation models, and may...

  6. How stationary are the internal tides in a high-resolution global ocean circulation model?

    NASA Astrophysics Data System (ADS)

    Shriver, Jay F.; Richman, James G.; Arbic, Brian K.

    2014-05-01

    The stationarity of the internal tides generated in a global eddy-resolving ocean circulation model forced by realistic atmospheric fluxes and the luni-solar gravitational potential is explored. The root mean square (RMS) variability in the M2 internal tidal amplitude is approximately 2 mm or less over most of the ocean and exceeds 2 mm in regions with larger internal tidal amplitude. The M2 RMS variability approaches the mean amplitude in weaker tidal areas such as the tropical Pacific and eastern Indian Ocean, but is smaller than the mean amplitude near generation regions. Approximately 60% of the variance in the complex M2 tidal amplitude is due to amplitude-weighted phase variations. Using the RMS tidal amplitude variations normalized by the mean tidal amplitude (normalized RMS variability (NRMS)) as a metric for stationarity, low-mode M2 internal tides with NRMS < 0.5 are stationary over 25% of the deep ocean, particularly near the generation regions. The M2 RMS variability tends to increase with increasing mean amplitude. However, the M2 NRMS variability tends to decrease with increasing mean amplitude, and regions with strong low-mode internal tides are more stationary. The internal tide beams radiating away from generation regions become less stationary with distance. Similar results are obtained for other tidal constituents with the overall stationarity of the constituent decreasing as the energy in the constituent decreases. Seasonal variations dominate the RMS variability in the Arabian Sea and near-equatorial oceans. Regions of high eddy kinetic energy are regions of higher internal tide nonstationarity.

  7. The Global S$_1$ Ocean Tide

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G. D.

    2003-01-01

    The small S$_1$ ocean tide is caused primarily by diurnal atmospheric pressure loading. Its excitation is therefore unlike any other diurnal tide. The global character of $S-1$ is here determined by numerical modeling and by analysis of Topex/Poseidon satellite altimeter data. The two approaches yield reasonably consistent results, and large ( $ greater than $l\\cm) amplitudes in several regions are further confirmed by comparison with coastal tide gauges. Notwithstanding their excitation differences, S$-1$ and other diurnal tides are found to share several common features, such as relatively large amplitudes in the Arabian Sea, the Sea of Okhotsk, and the Gulf of Alaska. The most noticeable difference is the lack of an S$-1$ Antarctic Kelvin wave. These similarities and differences can be explained in terms of the coherences between near-diurnal oceanic normal modes and the underlying tidal forcings. While gravitational diurnal tidal forces excite primarily a 28-hour Antarctic-Pacific mode, the S$_1$ air tide excites several other near-diurnal modes, none of which has large amplitudes near Antarctica.

  8. Development of Operational Wave-Tide-Storm surges Coupling Prediction System

    NASA Astrophysics Data System (ADS)

    You, S. H.; Park, S. W.; Kim, J. S.; Kim, K. L.

    2009-04-01

    uncoupling and coupling cases for each typhoon. When the typhoon Nabi hit at southern coast of Kyushu, predicted significant wave height reached over 10 m. The difference of significant wave height between wave and wave-tide-storm surges model represents large variation at the southwestern coast of Korea with about 0.5 m. Other typhoon cases also show similar results with typhoon Nabi case. For typhoon Shanshan case the difference of significant wave height reached up to 0.3 m. When the typhoon Nari was affected in the southern coast of Korea, predicted significant wave height was about 5m. The typhoon Nari case also shows the difference of significant wave height similar with other typhoon cases. Using the observation from ocean buoy operated by KMA, we compared wave information simulated by wave and wave-storm surges coupling model. The significant wave height simulated by wave-tide-storm surges model shows the tidal modulation features in the western and southern coast of Korea. And the difference of significant wave height between two models reached up to 0.5 m. The coupling effect also can be identified in the wave direction, wave period and wave length. In addition, wave spectrum is also changeable due to coupling effect of wave-tide-storm surges model. The development, testing and application of a coupling module in which wave-tide-storm surges are incorporated within the frame of KMA Ocean prediction system, has been considered as a step forward in respect of ocean forecasting. In addition, advanced wave prediction model will be applicable to the effect of ocean in the weather forecasting system. The main purpose of this study is to show how the coupling module developed and to report on a series of experiments dealing with the sensitivities and real case prediction of coupling wave-tide-storm surges prediction system.

  9. The IERS Special Bureau for Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Chao, B. F.; Desai, S. D.

    2002-01-01

    The Global Geophysical Fluids Center of the International Earth Rotation Service (IERS) comprises 8 special bureaus, one of which is the Special Bureau for Tides. Its purpose is to facilitate studies related to tidal effects in earth rotation. To that end it collects various relevant datasets and distributes them, primarily through its website at bowie.gsfc.nasa.gov/ggfc/tides. Example datasets include tabulations of tidal variations in angular momentum and in earth rotation as estimated from numerical ocean tide models and from meteorological reanalysis products. The web site also features an interactive tidal prediction "machine" which generates tidal predictions (e.g., of UT1) from lists of harmonic constants. The Special Bureau relies on the tidal and earth-rotation communities to build and enlarge its datasets; further contributions from this community are most welcome.

  10. The Atmospheric Tides Middle Atmosphere Program (ATMAP)

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1989-01-01

    Atmospheric tides, oscillations in meteorological fields occurring at subharmonics of a solar or lunar day, comprise a major component of middle atmosphere global dynamics. The purpose of the 1982 to 1986 Atmospheric Tides Atmosphere Program (ATMAP) was to foster an interaction between experimentalists, data analysts, and theoreticians and modelers, in order to better understand the physical mechanisms governing tides and their relationships to other scales of motion, and to thereby explain features of observed tidal structures in the mesosphere and lower thermosphere. The ATMAP consisted of seven observational campaigns, five workshops and a climatological study. A historical perspective is provided along with a summary of major results, conclusions, and recommendations for future study which have emerged from the ATMAP.

  11. Modelling alongshore flow in a semi-enclosed lagoon strongly forced by tides and waves

    NASA Astrophysics Data System (ADS)

    Taskjelle, Torbjørn; Barthel, Knut; Christensen, Kai H.; Furaca, Noca; Gammelsrød, Tor; Hoguane, António M.; Nharreluga, Bilardo

    2014-08-01

    Alongshore flows strongly driven by tides and waves is studied in the context of a one-dimensional numerical model. Observations from field surveys performed in a semi-enclosed lagoon (1.7 km×0.2 km) outside Xai-Xai, Mozambique, are used to validate the model results. The model is able to capture most of the observed temporal variability of the current, but sea surface height tends to be overestimated at high tide, especially during high wave events. Inside the lagoon we observed a mainly uni-directional alongshore current, with speeds up to 1 ms-1. The current varies primarily with the tide, being close to zero near low tide, generally increasing during flood and decreasing during ebb. The observations revealed a local minimum in the alongshore flow at high tide, which the model was successful in reproducing. Residence times in the lagoon were calculated to be less than one hour with wave forcing dominating the flushing. At this beach a high number of drowning casualties have occurred, but no connection was found between them and strong current events in a simulation covering the period 2011-2012.

  12. Internal Tides in the Western Gulf of Maine During Summer:1996

    NASA Astrophysics Data System (ADS)

    Brown, W. S.; Yu, Z.

    2008-12-01

    The summer internal tide in Wilkinson Basin is described in terms of a set moored currents measured at depths of 4m, 80m, 150m and 220m respectively between late August and mid-October 1996. The summer mean currents at each level were about 3 cm/s and generally directed along-isobaths. Most of the current variance was due to the semidiurnal tides, with the external M2 tidal ellipses generally oriented across- isobath (310oT-130oT). The winter external tidal variability was removed from the total summer currents leaving a residual that is dominated by M2 surface-intensified internal tidal currents that are coherent with the external tide. The semidiurnal tidal band statistics explain a dominant M2 tidal response that consists of a strong depth-independent profile of nearly rectilinear external tidal currents oriented in the across-isobath direction (~320oT) plus a weaker of surface-intensified (i.e. depth-dependent or baroclinic) internal tidal currents that are coherent with the external tide. The current shear between 4m and 80m is consistent with the relatively shallow pycnocline. These internal tides are probably generated through the interaction of the external (or barotropic) tidal currents with the steep southeast-facing slope of Jeffrey's Bank. These highly nonlinear internal tidal waves (or sometimes called internal solitons) intermittently evolve into packets of higher frequency internal wave packets that are present in our 5-minute current records.

  13. Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt

    NASA Astrophysics Data System (ADS)

    Kent, D. V.; Muttoni, G.

    2012-09-01

    The small reservoir of carbon dioxide in the atmosphere (pCO2) that modulates climate through the greenhouse effect reflects a delicate balance between large fluxes of sources and sinks. The major long-term source of CO2 is global outgassing from sea-floor spreading, subduction, hotspot activity, and metamorphism; the ultimate sink is through weathering of continental silicates and deposition of carbonates. Most carbon cycle models are driven by changes in the source flux scaled to variable rates of ocean floor production. However, ocean floor production may not be distinguishable from being steady since 180 Ma. We evaluate potential changes in sources and sinks of CO2 for the past 120 Ma in a paleogeographic context. Our new calculations show that although decarbonation of pelagic sediments in Tethyan subduction likely contributed to generally high pCO2 levels from the Late Cretaceous until the Early Eocene, shutdown of Tethyan subduction with collision of India and Asia at the Early Eocene Climate Optimum at around 50 Ma was inadequate to account for the large and prolonged decrease in pCO2 that eventually allowed the growth of significant Antarctic ice sheets by around 34 Ma. Instead, variation in area of continental basaltic provinces in the equatorial humid belt (5° S-5° N) seems to be the dominant control on how much CO2 is retained in the atmosphere via the silicate weathering feedback. The arrival of the highly weatherable Deccan Traps in the equatorial humid belt at around 50 Ma was decisive in initiating the long-term slide to lower atmospheric pCO2, which was pushed further down by the emplacement of the 30 Ma Ethiopian Traps near the equator and the southerly tectonic extrusion of SE Asia, an arc terrane that presently is estimated to account for 1/4 of CO2 consumption from all basaltic provinces that account for ~1/3 of the total CO2 consumption by continental silicate weathering (Dessert et al., 2003). A negative climate-feedback mechanism that

  14. Long Term Observations of the low Latitude (1,1) Diurnal Migrating Tide From WINDII, HRDI and TIDI

    NASA Astrophysics Data System (ADS)

    Niciejewski, R.; Skinner, W.; Gell, D.; Cooper, M.; Marshall, A.; Killeen, T.; Solomon, S.; Wu, Q.; Ortland, D.; Drob, D.; Emmert, J.; Shepherd, G.; Zhang, S.; Solheim, B.

    2006-05-01

    The dominant feature in the global scale wind field in the low latitude mesosphere and lower thermosphere (MLT) region is the solar diurnal migrating tide, classically represented by the (1,1) Hough function. The meridional component of the horizontal neutral wind vector is relatively stable in this region making it possible to estimate the daily (1,1) amplitude and phase*. Observations of the MLT winds have been performed from satellite platforms by HRDI and WINDII (UARS) and by TIDI (TIMED) since September 1991 providing a unique and continuous global perspective of the classical (1,1) tide for nearly 15 years. This paper will describe new results from HRDI, WINDII, and TIDI of the daily and annual variation of the (1,1) tide. A long-term interannual variability is clear in the data sets with the amplitude of the (1,1) tide peaking near 100 m/s within a week of the March equinox in 1993, 1995, 1999, 2002, and 2004. Lesser peaks occur during intervening years as well as about two weeks following the September equinox. A secondary result that will be discussed is the correspondence between coincident (1,1) tide observations by different pairs of experiments (HRDI/WINDII) and (HRDI/TIDI). *Burrage, M. D., M. E. Hagan, W. R. Skinner, D. L. Wu, and P. B. Hays, Long-term variability in the solar diurnal tide observed by HRDI and simulated by the GSWM, Geophys. Res. Lett., 22, 2641, 1995.

  15. FINITE ELEMENT MODEL FOR TIDES AND CURRENTS WITH FIELD APPLICATIONS.

    USGS Publications Warehouse

    Walters, Roy A.

    1988-01-01

    A finite element model, based upon the shallow water equations, is used to calculate tidal amplitudes and currents for two field-scale test problems. Because tides are characterized by line spectra, the governing equations are subjected to harmonic decomposition. Thus the solution variables are the real and imaginary parts of the amplitude of sea level and velocity rather than a time series of these variables. The time series is recovered through synthesis. This scheme, coupled with a modified form of the governing equations, leads to high computational efficiency and freedom from excessive numerical noise. Two test-cases are presented. The first is a solution for eleven tidal constituents in the English Channel and southern North Sea, and three constituents are discussed. The second is an analysis of the frequency response and tidal harmonics for south San Francisco Bay.

  16. Non-Stationary Internal Tides Observed with Satellite Altimetry

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Zaron, E. D.

    2011-01-01

    Temporal variability of the internal tide is inferred from a 17-year combined record of Topex/Poseidon and Jason satellite altimeters. A global sampling of along-track sea-surface height wavenumber spectra finds that non-stationary variance is generally 25% or less of the average variance at wavenumbers characteristic of mode-l tidal internal waves. With some exceptions the non-stationary variance does not exceed 0.25 sq cm. The mode-2 signal, where detectable, contains a larger fraction of non-stationary variance, typically 50% or more. Temporal subsetting of the data reveals interannual variability barely significant compared with tidal estimation error from 3-year records. Comparison of summer vs. winter conditions shows only one region of noteworthy seasonal changes, the northern South China Sea. Implications for the anticipated SWOT altimeter mission are briefly discussed.

  17. Enabling Philippine Farmers to Adapt to Climate Variability Using Seasonal Climate and Weather Forecast with a Crop Simulation Model in an SMS-based Farmer Decision Support System

    NASA Astrophysics Data System (ADS)

    Ebardaloza, J. B. R.; Trogo, R.; Sabido, D. J.; Tongson, E.; Bagtasa, G.; Balderama, O. F.

    2015-12-01

    Corn farms in the Philippines are rainfed farms, hence, it is of utmost importance to choose the start of planting date so that the critical growth stages that are in need of water will fall on dates when there is rain. Most farmers in the Philippines use superstitions and traditions as basis for farming decisions such as when to start planting [1]. Before climate change, superstitions like planting after a feast day of a saint has worked for them but with the recent progression of climate change, farmers now recognize that there is a need for technological intervention [1]. The application discussed in this paper presents a solution that makes use of meteorological station sensors, localized seasonal climate forecast, localized weather forecast and a crop simulation model to provide recommendations to farmers based on the crop cultivar, soil type and fertilizer type used by farmers. It is critical that the recommendations given to farmers are not generic as each farmer would have different needs based on their cultivar, soil, fertilizer, planting schedule and even location [2]. This application allows the farmer to inquire about whether it will rain in the next seven days, the best date to start planting based on the potential yield upon harvest, when to apply fertilizer and by how much, when to water and by how much. Short messaging service (SMS) is the medium chosen for this application because while mobile penetration in the Philippines is as high as 101%, the smart phone penetration is only at 15% [3]. SMS has been selected as it has been identified as the most effective way of reaching farmers with timely agricultural information and knowledge [4,5]. The recommendations while derived from making use of Automated Weather Station (AWS) sensor data, Weather Research Forecasting (WRF) models and DSSAT 4.5 [9], are translated into the local language of the farmers and in a format that is easily understood as recommended in [6,7,8]. A pilot study has been started

  18. Temporal variability of CO2 and N2O emissions in an agricultural long-term field trial regarding effects of different management practices and extreme weather effects

    NASA Astrophysics Data System (ADS)

    Koal, Philipp; Schilling, Rolf; Gerl, Georg; Pritsch, Karin; Munch, Jean Charles

    2016-04-01

    In order to achieve a reduction of greenhouse gas emissions, modern agronomic management practices need to be established. Therefore, to assess the effect of different farming practices on greenhouse gas emissions, reliable data are required. The experiment covers and compares main aspects of agricultural management for a better implementation of sustainable land use. The focus lies on the determination and interpretation of greenhouse gas emissions, where the effects of diverse tillage systems and fertilisation practices of an integrated farming system as well as the impacts of extreme weather conditions are observed. In addition, with analysis of the alterable biological, physical and chemical soil properties a link between the impact of different management systems on greenhouse gas emissions and the observed cycle of matter in the soil, especially the nitrogen and carbon cycle, is enabled. Measurements have been carried out on long-term field trials at the Research Farm Scheyern located in a Tertiary hilly landscape approximately 40 km north of Munich (South Germany). The long-term integrated farming system trial was started in 1992. Since then parcels of land (each around 0.2-0.4 ha) with a particular interior plot set-up have been conducted with the same crop rotation, tillage and fertilisation practice referring to integrated farming management. Thus, the management impacts on the soil of more than 20 years have been examined. Fluxes of CH4, N2O and CO2 have been monitored since 2007 for the integrated farming system trial using an automated system which consists of chambers (0.4 m2 area) with a motor-driven lid, an automated gas sampling unit, an on-line gas chromatographic analysis system, and a control and data logging unit. Precipitation and temperature data have been observed for the experimental field to include weather effects. The main outcomes are the analysis of temporal and spatial dynamics of greenhouse gas emissions influenced by management

  19. A Model for Teaching the Dynamical Theory of Tides.

    ERIC Educational Resources Information Center

    Railsback, L. Bruce

    1991-01-01

    The dynamical theory of tides is often neglected in teaching oceanography because students have difficulty in visualizing the movements of the tides across the glove. A schematic diagram portraying amphidromic systems as mechanical gears helps overcome these problems. (Author)

  20. Ionospheric signatures of non-migrating tides and stratospheric warming

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Stolle, Claudia; Häusler, Kathrin

    2010-05-01

    Observational data bases from recent years provided more and more evidence that climate and weather phenomena influence the dynamics of the high atmosphere. In the first part of this presentation we will address the dynamical interaction caused by non-migrating tides. Several of these tidal modes are generated in the lower atmosphere and are believed to propagate all the way up to the exosphere. Quantities that reflect the characteristics of the tides very well, are thermospheric temperature and wind. The dynamics of the neutrals is partly transferred to charged particles in the ionospheric E-layer. For that reason tidal signals are also present in the ionospheric E and F region. We show, as examples, the effect on the equatorial electrojet (EEJ), vertical plasma drift and F region electron density. Since the coupling conditions and strength between neutral and charged particles vary over the course of a day (a year, a solar cycle), the recovery of the complete ionospheric tidal signals is complex. We will present the amplitude and annual variation for the most prominent tidal components. A very recent topic of vertical coupling is the influence of sudden stratospheric warming (SSW) on the ionospheric electrodynamics. SSW has been shown to modify among others the diurnal variation of the vertical plasma drift and the electric field at equatorial latitudes. We will present global observations of the EEJ and its response to SSW events in 2002/2003. A typical feature is an enhancement of the EEJ intensity in the pre-noon hours and a reduction in the afternoon. Possible mechanisms causing these modifications will be discussed.

  1. The science of space weather.

    PubMed

    Eastwood, Jonathan P

    2008-12-13

    The basic physics underpinning space weather is reviewed, beginning with a brief overview of the main causes of variability in the near-Earth space environment. Although many plasma phenomena contribute to space weather, one of the most important is magnetic reconnection, and recent cutting edge research in this field is reviewed. We then place this research in context by discussing a number of specific types of space weather in more detail. As society inexorably increases its dependence on space, the necessity of predicting and mitigating space weather will become ever more acute. This requires a deep understanding of the complexities inherent in the plasmas that fill space and has prompted the development of a new generation of scientific space missions at the international level. PMID:18812302

  2. Assessing the Economic Impacts of Weather

    NASA Astrophysics Data System (ADS)

    Lazo, J. K.

    2008-05-01

    Understanding the socio-economic impacts of weather provides a basis for prioritizing actions to mitigate and respond to weather events and understanding the value of improvements in weather forecasts. In this talk we discuss two studies of the economic impacts of weather: (1) an empirical study of the sensitivity of state-sector level economic activity to weather variability and (2) an assessment of the quality of data on storm damages in the US as primarily collected through the National Weather Service's Storm Data Program. In the first study, 24 years of state level sector economic data and historical weather observations are used to form a panel combining weather information with economic data. A translog function is estimated of sectoral sensitivity and vulnerability to weather variability. Eleven sectors are ranked based on their degree of sensitivity to weather, states more sensitive to weather impacts are identified, and the aggregate dollar amount of variation in U.S. economic activity attributable to weather variability is calculated. Estimates indicate that US economic output varies by about 3.4% due to weather variability. While considerably smaller than prior estimates, our estimate represents about 469 billion a year in 2007 dollars. In our work to update and revise damage data in the Extreme Weather Sourcebook (www.sip.ucar.edu/sourcebook), we have confronted issues concerning the depth, accuracy and consistency of storm damage data collection. This type of data has been used in many studies exploring changes in weather impacts over time but there has been little recognition of the quality of the data. In the second study reported here, we examine issues with weather induced damage data quality to prompt a dialogue about reliability of scattered and inconsistent data from multiple sources. We hope this will lead to efforts to reduce the error in reported damages and to better reporting and organization of storm damage data in the future. We advocate

  3. New Miscellaneous Results in Tides from Topex/Poseidon

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, G.; Cartwright, D.; Smith, David E. (Technical Monitor)

    2000-01-01

    This paper describes a variety of new results concerning ocean tides that have been derived from Topex/Poseidon satellite altimeter data. Most of these results are based on new tidal solutions employing nearly 8 years of data. The topics covered include internal tides and long-period tides.

  4. Nonlinearity in rock - Evidence from earth tides

    NASA Technical Reports Server (NTRS)

    Agnew, D. C.

    1981-01-01

    The earth is sinusoidally stressed by tidal forces; if the stress-strain relation for rock is nonlinear, energy should appear in an earth tide record at frequencies which are multiples of those of the larger tidal lines. An examination of the signals to be expected for different nonlinear deformation laws shows that for a nonlinear response without dissipation, the largest anomalous signal should occur at twice the forcing frequency, whereas for nonlinear laws involving dissipation (cusped hysteresis loops) the anomalous signal will be greatest at three times this frequency. The size of the signal in the dissipative case depends on the amount by which dissipation affects the particular response being measured. For measurements of strain tides this depends on whether dissipation is assumed to be present throughout the earth or localized around the point of measurement. An analysis of 5.7 years of strain tide records from Pinon Flat, California, shows a small signal at twice the frequency of the largest (M2) tide.

  5. Parents Who Moved against the Tide.

    ERIC Educational Resources Information Center

    Perske, Robert

    2003-01-01

    This article recounts the historical discrimination against children with mental retardation and the extraordinary efforts made by parents of children with disabilities to speak out against the tide that dehumanized their children. The growth of national, state, and local Arcs and parent advocacy efforts are discussed. (Contains 5 references.) (CR)

  6. Using Tide Data in Introductory Classes

    ERIC Educational Resources Information Center

    De Jong, Marvin L.

    2006-01-01

    Oceantides are not typically high in our consciousness here in Missouri, but in teaching astronomy and physical science the subject always comes up, and teachers of physical science and astronomy are all quite familiar with the textbook explanations. Our goal here is not to explain tides but to make some suggestions about how, on their own,…

  7. Fracture characterization using Earth tide analysis

    NASA Astrophysics Data System (ADS)

    Burbey, Thomas J.

    2010-01-01

    SummaryWells tapping confined aquifer systems are known to commonly produce water-level fluctuations caused by strain-induced Earth tides. In this investigation, a straightforward methodology is presented for quantifying the specific storage and secondary porosity of a fractured fault-zone aquifer system using Earth tides. Water-level and barometric pressure head data are smoothed and then filtered to remove low frequency responses. The resulting tidal signals are used in the program BAYTAP-G to yield amplitude and phase shifts of all the major tidal groups. The resulting tidal parameters can be used to compute the time-dependent volumetric strain caused by the M 2 and O 1 tides. Stress-strain hysteresis loops are produced when the reduced water levels are compared to the volumetric strain induced by these tides. For amplification factors near unity (representing the ratio of pressure response to tidal loading in the fracture to water-level response in the well) the slopes of the loops represent the specific storage of the fracture. The barometric efficiency and specific storage can then be used to estimate a secondary porosity and other parameters of the aquifer system. This analysis was carried out at the Fractured Rock research Site (FRS) in the Blue Ridge Physiographic Province in Floyd County, Virginia.

  8. In Brief: Red tide Web site

    NASA Astrophysics Data System (ADS)

    Showstack, Randy; Kumar, Mohi

    2008-06-01

    The U.S. National Oceanic and Atmospheric Administration has established the NOAA New England Red Tide Information Center to help people understand the significant red tides that are predicted to form there later this spring. The site (http://www.oceanservice.noaa.gov/redtide) will provide a summary of the current red tide situation and its potential harmful impacts on humans and animals and will serve as a central repository of information. The site also will have direct links to news releases, changes to relevant federal fishing regulations, links to closures of shellfish waters, and links to state agency Web sites with localized information. In addition, the site will have information about NOAA's scientific response effort as well as information from several other sources including NOAA's major response partner, the Woods Hole Oceanographic Institution (WHOI). On 24 April, WHOI scientists, using forecast models developed with NOAA funding support, predicted ``that excess winter precipitation has set the stage for a harmful algal bloom similar to the historic red tide of 2005.'' That bloom shut down shellfish beds from the Bay of Fundy to Martha's Vineyard for several months.

  9. Small geophysical signals detected in differences of altimetric tides and bottom-pressure tides

    NASA Astrophysics Data System (ADS)

    Ray, R. D.

    2013-12-01

    Very precise tidal estimates derived from seafloor pressure measurements and from two decades of satellite altimetry are capable of revealing tiny, subtle signals in their differences. In particular, these differences can place constraints on models of atmospheric tides and solid tides. Such signals arise because altimetry is sensitive to the solid tide while bottom pressure (BP) is not, while BP is sensitive to the air tide while altimetry is not (not directly anyway). I have constructed a database of precise BP tide estimates from 151 deep-ocean stations, most based on multiple years of hourly data. The relationship between bottom pressure and equivalent sea-surface elevation must be carefully handled, since it depends on ocean stratification and the compressibility of seawater. The altimeter-BP rms differences are 5 mm or better. In these differences, the air tide is easily detected at the S1 and S2 periods and more marginally detected at the T2 and K1 periods (the latter represent seasonal sidelines of either S1 or S2); a comparison of various air-tide models favors one derived from recent 3-hourly ECMWF operational analyses. Results also show that altimetry can benefit from correcting for crustal loading by the S2 air tide; the signal is only 1.4 mm or less and has previously been ignored, but it is detectable in the altimeter-BP differences. Similarly altimetry must be corrected for the presence of the air tide in the dry troposphere correction. Finally differences also allow Love numbers to be estimated at the M2, O1, and K1 periods, with the latter clearly showing suppression from the free core-nutation resonance. However, recent estimates just published by Krasna and colleagues, using VLBI data, are far more accurate, in part because VLBI need not contend with large, possibly inconsistent ocean signals in their data. Our results could be improved once baroclininc tides are properly accounted for, but these tides, with wavelengths of order 100 km, are

  10. Modulation of Late Cretaceous and Cenozoic climate by variable drawdown of atmospheric pCO2 from weathering of basaltic provinces on continents drifting through the equatorial humid belt

    NASA Astrophysics Data System (ADS)

    Kent, D. V.; Muttoni, G.

    2013-03-01

    The small reservoir of carbon dioxide in the atmosphere (pCO2) that modulates climate through the greenhouse effect reflects a delicate balance between large fluxes of sources and sinks. The major long-term source of CO2 is global outgassing from sea-floor spreading, subduction, hotspot activity, and metamorphism; the ultimate sink is through weathering of continental silicates and deposition of carbonates. Most carbon cycle models are driven by changes in the source flux scaled to variable rates of ocean floor production, but ocean floor production may not be distinguishable from being steady since 180 Ma. We evaluate potential changes in sources and sinks of CO2 for the past 120 Ma in a paleogeographic context. Our new calculations show that decarbonation of pelagic sediments by Tethyan subduction contributed only modestly to generally high pCO2 levels from the Late Cretaceous until the early Eocene, and thus shutdown of this CO2 source with the collision of India and Asia at the early Eocene climate optimum at around 50 Ma was inadequate to account for the large and prolonged decrease in pCO2 that eventually allowed the growth of significant Antarctic ice sheets by around 34 Ma. Instead, variation in area of continental basalt terranes in the equatorial humid belt (5° S-5° N) seems to be a dominant factor controlling how much CO2 is retained in the atmosphere via the silicate weathering feedback. The arrival of the highly weatherable Deccan Traps in the equatorial humid belt at around 50 Ma was decisive in initiating the long-term slide to lower atmospheric pCO2, which was pushed further down by the emplacement of the 30 Ma Ethiopian Traps near the equator and the southerly tectonic extrusion of SE Asia, an arc terrane that presently is estimated to account for 1/4 of CO2 consumption from all basaltic provinces that account for ~1/3 of the total CO2 consumption by continental silicate weathering (Dessert et al., 2003). A negative climate-feedback mechanism

  11. Modeling the effect of tides and waves on benthic biofilms

    NASA Astrophysics Data System (ADS)

    Mariotti, G.; Fagherazzi, S.

    2012-12-01

    We propose a simple model for growth of benthic biofilm subject to variable hydrodynamic disturbances and with a biofilm-dependent erodibility (biostabilization). Model results show that, for disturbances with equal intensity, the biofilm is eroded or not depending on its current biomass, which is a function of the past evolution trajectory. Because of the finite time needed for a biofilm to develop, both the intensity and frequency of periodical disturbances, such as tidal currents, determine whether the biofilm can approach its equilibrium biomass. Spring-neap tidal modulation favors biofilm development, since the reduction of the current shear stress associated with neap tides allows biofilm growth, thus increasing biostabilization and the biofilm's likelihood to withstand the subsequent energetic spring tides. On the other hand, diurnal tidal modulations are negative for biofilm development, because the diel biofilm growth is almost negligible. Under stochastic disturbances associated with wind waves, there are two most-likely states for the biofilm biomass: either close to zero or close to the equilibrium value, depending on wave intensity. If biostabilization is reduced or eliminated, the probability of intermediate values for biofilm biomass becomes also significant. The role of biostabilization is hence to exacerbate the probability of the end-member states. Finally, because of the nonmonotonic relationship between water depth and wave induced bed stresses, only extremely shallow and deep areas favor biofilm persistence. If light attenuation with depth is considered, deep water becomes unsuitable for biofilm growth when water turbidity is high.

  12. Nonmigrating diurnal tides in the equatorial middle atmosphere

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.

    1991-01-01

    Data from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) are used to extend the analysis of diurnal tides in the middle atmosphere to include the zonally symmetric and eastward propagating components. These modes show vertical and meridional structures that are generally consistent with the predictions of linear tidal theory. The zonal and meridional wind fields are calculated from the tidal temperatures. Diurnal perturbations in LIMS temperature and derived winds agree well with equinoctial model calculations. Comparisons with day-night differences of radiosonde temperature and rocket winds show qualitative agreement in vertical structure and amplitude. The zonally symmetric and eastward migrating tidal components show a higher degree of temporal variability than the sun-synchronous component. These modes at times contribute substantially to the diurnal signal in wind and temperature, with combined amplitudes equal to or in excess of the amplitude of the main migrating diurnal tide. The observed vertical phase variations suggest that their forcing may originate below the stratosphere.

  13. Long-term increase in New York Harbor storm tides, 1844-present

    NASA Astrophysics Data System (ADS)

    Talke, S. A.; Orton, P. M.; Jay, D. A.

    2014-12-01

    Eight of the largest twenty recorded water levels in the New York Harbor region recorded since 1821 occurred after 1990, and three of the 10 largest have occurred since 2010 (March 2010, August 2011, and October 2012). Archival research and numerical modeling indicates, however, that the storm surge during an 1821 hurricane exceeded that from hurricane Sandy (~3.5m vs. 2.8m). To investigate flood risk we recover archival tide gauge data back to 1844 and evaluate whether the recent cluster of extreme water levels is random, driven solely by sea-level rise, or is caused by changes to storm tides (the sum of storm surge and tidal effects). Results indicate both long term trends and decadal variability in the annual maximum storm tide (AMST). Approximately half of long-term AMST variability is explained by a long term increase in storm tides, while the remainder is explained by the North Atlantic Oscillation. The magnitude of the 10 year return period storm tide has increased by 0.28m. Combined with a 0.44m increase in local sea level since 1856, the 10 year flood level has increased by approximately 0.72 ± 0.25m, and magnified the annual probability of overtopping the nominal Manhattan seawall from less than 1% to about 20-25%. Further, including the 1821 event in extreme value analysis suggests that the return period of hurricane Sandy storm tides is much smaller than other estimates. Though the cause of the long-term AMST trend is unclear, analysis of tidal properties indicates that long-wave propagation in New York harbor has shifted since the 1850s. Because storm surge is also a long-wave with a component in the tidal band, at least a portion of changed storm-tide hazard is likely driven by local anthropogenic alterations of the region's waterways. Along with sea-level rise, local development and climate-induced shifts to the North Atlantic Oscillation may continue to affect the New York harbor storm tide hazard in the future.

  14. Arctic Ocean tides from GRACE satellite accelerations

    NASA Astrophysics Data System (ADS)

    Killett, B.; Wahr, J.; Desai, S.; Yuan, D.; Watkins, M.

    2011-11-01

    Models are routinely used to remove the effects of global ocean tides from GRACE data during processing to reduce temporal aliasing into monthly GRACE solutions. These models have typically been derived using data from satellite altimeters such as TOPEX/Poseidon. Therefore the Arctic ocean components of tide models are not constrained by altimetry data, potentially resulting in errors that are likely to alias into monthly GRACE gravity fields at all latitudes. Seven years of GRACE inter-satellite accelerations are inverted to solve for corrections to the amplitude and phase of major solar and lunar ocean tides at latitudes north of 50°N using a mascon approach. The tide model originally applied to our data was FES2004, truncated to maximum degree lmax = 90. Simulations are performed to verify that our inversion algorithm works as designed. Uncertainty estimates are derived from tidal solutions on land, and by subtracting two independent solutions that each use 3.5 years of data. Features above the noise floor in the M2, K1, S2, and O1 solutions likely represent errors in FES2004. Errors due to truncating the spherical harmonic expansion of FES2004 are too small, and errors in the land mask model (needed to transform sea surface heights into mass) only affect coastal areas and do not produce similar relative amplitudes for any examined tides. In the oceans north of 50°N, these residuals tend to reduce the FES2004 amplitudes for M2, K1, S2, and O1. Reductions in the variance of accelerations not used in our inversion suggest that our results can be used to improve GRACE processing.

  15. A tide prediction and tide height control system for laboratory mesocosms

    PubMed Central

    Long, Jeremy D.

    2015-01-01

    Experimental mesocosm studies of rocky shore and estuarine intertidal systems may benefit from the application of natural tide cycles to better replicate variation in immersion time, water depth, and attendant fluctuations in abiotic and edaphic conditions. Here we describe a stand-alone microcontroller tide prediction open-source software program, coupled with a mechanical tidal elevation control system, which allows continuous adjustment of aquarium water depths in synchrony with local tide cycles. We used this system to monitor the growth of Spartina foliosa marsh cordgrass and scale insect herbivores at three simulated shore elevations in laboratory mesocosms. Plant growth decreased with increasing shore elevation, while scale insect population growth on the plants was not strongly affected by immersion time. This system shows promise for a range of laboratory mesocosm studies where natural tide cycling could impact organism performance or behavior, while the tide prediction system could additionally be utilized in field experiments where treatments need to be applied at certain stages of the tide cycle. PMID:26623195

  16. Weather in the News.

    ERIC Educational Resources Information Center

    Markle, Sandra

    1989-01-01

    A discussion of TV weather forecasting introduces this article which features several hands-on science activities involving observing, researching, and experimenting with the weather. A reproducible worksheet on the reliability of weather forecasts is included. (IAH)

  17. Winter Weather Checklists

    MedlinePlus

    ... Planning Information on Specific Types of Emergencies Winter Weather Checklists Language: English Español (Spanish) Recommend on Facebook ... emergency instructions National Oceanic and Atmospheric Administration (NOAA) weather radio receiver for listening to National Weather Service ...

  18. Forecasting the Weather.

    ERIC Educational Resources Information Center

    Bollinger, Richard

    1984-01-01

    Presents a computer program which predicts the weather based on student input of such weather data as wind direction and barometric pressure. Also provides procedures for several hands-on, weather-related activities. (JN)

  19. The association of weather variability and under five malaria mortality in KEMRI/CDC HDSS in Western Kenya 2003 to 2008: a time series analysis.

    PubMed

    Sewe, Maquins; Rocklöv, Joacim; Williamson, John; Hamel, Mary; Nyaguara, Amek; Odhiambo, Frank; Laserson, Kayla

    2015-02-01

    Malaria is among the leading causes of mortality in the younger under-five group of children zero to four years of age. This study aims at describing the relationship between rainfall and temperature on under-five malaria or anaemia mortality in Kenya Medical Research Institute and United States Centers for Disease Control (KEMRI/CDC) Health and Demographic Surveillance System (HDSS). This study was conducted through the ongoing KEMRI and CDC collaboration. A general additive model with a Poisson link function was fit to model the weekly association of lagged cumulative rainfall and average temperature on malaria/anemia mortality in KEMRI/CDC HDSS for the period 2003 to 2008. A trend function was included in the model to control for time trends and seasonality not explained by weather fluctuations. 95% confidence intervals was presented with estimates. Malaria or anemia mortality was found to be associated with changes in temperature and rainfall in the KEMRI HDSS, with a delay up to 16 weeks. The empirical estimates of associations describe established biological relationships well. This information, and particularly, the strength of the relationships over longer lead times can highlight the possibility of developing a predictive forecast with lead times up to 16 weeks in order to enhance preparedness to high transmission episodes. PMID:25674784

  20. Impact of the 2013-2015 weather variability on seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species

    NASA Astrophysics Data System (ADS)

    van der Maaten, Ernst; Pape, Jonas; van der Maaten Theunissen, Marieke; Scharnweber, Tobias; Smiljanic, Marko; Wilmking, Martin

    2016-04-01

    Dendrometers are measurement devices that continuously monitor stem-size changes of trees without invasive sampling of the cambium. Dendrometers record both irreversible tree growth as well as reversible signals of stem water storage and depletion, making them important tools for studying tree water status, tree physiology and short-term growth responses of trees to weather fluctuations. In this study, a three-year dendrometer dataset (2013-2015) is used to study seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species (common hornbeam (Carpinus betulus L.), European beech (Fagus sylvatica L.), and pedunculate oak (Quercus robur L.)), growing in an unmanaged forest in northeastern Germany. Seasonal growth patterns (i.e. growth onset, cessation and duration) are analyzed in relation to environmental conditions, and forest meteorological factors driving daily stem-size changes are identified. Following dry conditions in 2014, especially the growth of beech was reduced. Oak was less affected, and displayed a distinct early growth onset for all study years.

  1. Prospects for Improved Forecasts of Weather and Short-Term Climate Variability on Subseasonal (2-Week to 2-Month) Times Scales

    NASA Technical Reports Server (NTRS)

    Schubert, Siegfried; Dole, Randall; vandenDool, Huug; Suarez, Max; Waliser, Duane

    2002-01-01

    This workshop, held in April 2002, brought together various Earth Sciences experts to focus on the subseasonal prediction problem. While substantial advances have occurred over the last few decades in both weather and seasonal prediction, progress in improving predictions on these intermediate time scales (time scales ranging from about two weeks to two months) has been slow. The goals of the workshop were to get an assessment of the "state of the art" in predictive skill on these time scales, to determine the potential sources of "untapped" predictive skill, and to make recommendations for a course of action that will accelerate progress in this area. One of the key conclusions of the workshop was that there is compelling evidence for predictability at forecast lead times substantially longer than two weeks. Tropical diabatic heating and soil wetness were singled out as particularly important processes affecting predictability on these time scales. Predictability was also linked to various low-frequency atmospheric "phenomena" such as the annular modes in high latitudes (including their connections to the stratosphere), the Pacific/North American (PNA) pattern, and the Madden Julian Oscillation (MJO). The latter, in particular, was highlighted as a key source of untapped predictability in the tropics and subtropics, including the Asian and Australian monsoon regions.

  2. On modeling migrating solar tides

    NASA Technical Reports Server (NTRS)

    Hagan, M. E.; Forbes, J. M.; Vial, F.

    1995-01-01

    Recent updates and extensions to a steady-state two-dimensional linearized model of global-scale atmospheric waves have facilitated improved calculations of those which are subharmonics of a solar day and propagate with the apparent motion of the sun. The model improvements are briefly described and some updated predictions of the migrating solar diurnal component are highlighted. The latter represent the first numerical modeling effort to examining the seasonal variability of the migrating diurnal harmonic as it propagates into the mesosphere and lower thermosphere.

  3. Climatology and temporal evolution of the atmospheric semidiurnal tide in present-day reanalyses

    NASA Astrophysics Data System (ADS)

    Díaz-Argandoña, J.; Ezcurra, A.; Sáenz, J.; Ibarra-Berastegi, G.; Errasti, I.

    2016-05-01

    The solar semidiurnal atmospheric tide (S2) was extracted from seven reanalysis data sets, including current data sets, such as CFSR (Climate Forecast System Reanalysis), MERRA (Modern-Era Retrospective Analysis for Research and Applications), ERA-Interim (ECMWF Reanalysis), and 20CR (Twentieth Century Reanalysis), and older frozen products, such as NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research), ERA-40 (ECMWF Reanalysis), and JRA-25 (Japanese 25 year Reanalysis). In this calculation, we emphasized the temporal variation of the tide. We also calculated the tidal error, which was sizable at high latitudes and over short averaging periods and large for 20CR at all latitudes. Because of the four standard daily samples, the interpolation scheme of van den Dool et al. (1997) was used when necessary. We found this method to be accurate for zonally averaged tides only. Comparing the climatology from the MERRA and CFSR S2 with a recent empirical tide model showed that MERRA better represented the geographical structure of the tide, especially its phase. We found a bias in the phase in all of the reanalysis data sets except for MERRA. The temporal evolution of the tide was inconsistent between the different data sets, although similar seasonal variations were observed. The seasonal cycle was also better depicted in MERRA. The S2 calculated from MERRA and satellite precipitation measurements from TRMM (Tropical Rainfall Measuring Mission) presented results that were inconsistent with the hypothesis in which rainfall latent heat release represents S2 forcing and functions as a source of S2 seasonal variability.

  4. eHEROES: where Space Weather and Communication meet

    NASA Astrophysics Data System (ADS)

    Vanlomel, Petra; Gressl, Corinna; Lapenta, Giovanni; Crosby, Norma B.; Cessateur, Gaël

    2014-05-01

    Involvement of people outside the scientific community in space weather becomes more and more an issue. To raise awareness and reach involvement, we have to come up with a tide communication plan that answers the questions: what, to whom, why, when, how, by whom? One of the tools to get peoples attention and to communicate about space weather is education, both formal and informal. In the FP7 project eHEROES, a considerable effort was put in communication and dissemination through education to different sorts of audiences. We will shed some light on 'Classroom', 'Hitchhiker's guide to space' and our Quiz-database.

  5. A Climatology of Fair-Weather Cloud Statistics at the Atmospheric Radiation Measurement Program Southern Great Plains Site: Temporal and Spatial Variability

    SciTech Connect

    Berg, Larry K.; Kassianov, Evgueni I.; Long, Charles N.; Gustafson, William I.

    2006-03-30

    In previous work, Berg and Stull (2005) developed a new parameterization for Fair-Weather Cumuli (FWC). Preliminary testing of the new scheme used data collected during a field experiment conducted during the summer of 1996. This campaign included a few research flights conducted over three locations within the Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. A more comprehensive verification of the new scheme requires a detailed climatology of FWC. Several cloud climatologies have been completed for the ACRF SGP, but these efforts have focused on either broad categories of clouds grouped by height and season (e.g., Lazarus et al. 1999) or height and time of day (e.g., Dong et al. 2005). In these two examples, the low clouds were not separated by the type of cloud, either stratiform or cumuliform, nor were the horizontal chord length (the length of the cloud slice that passed directly overhead) or cloud aspect ratio (defined as the ratio of the cloud thickness to the cloud chord length) reported. Lane et al. (2002) presented distributions of cloud chord length, but only for one year. The work presented here addresses these shortcomings by looking explicitly at cases with FWC over five summers. Specifically, we will address the following questions: •Does the cloud fraction (CF), cloud-base height (CBH), and cloud-top height (CTH) of FWC change with the time of day or the year? •What is the distribution of FWC chord lengths? •Is there a relationship between the cloud chord length and the cloud thickness?

  6. A gridded multisite weather generator and synchronization to observed weather data

    NASA Astrophysics Data System (ADS)

    Wilks, Daniel S.

    2009-10-01

    Procedures are described for constructing a daily multisite weather generator at a collection of arbitrary (e.g., gridded) locations and for synchronizing the gridded generator to observed weather series at a set of reference stations. The gridded generator is constructed by interpolating conventional single-station weather generator parameters using locally weighted regressions and producing coherent simulations of daily weather from them using spatial correlation functions. When implemented, the synchronization algorithm results in simulated spatial weather fields at the grid points that are consistent with daily weather observations at nearby locations for particular years. The synchronization is achieved by exploiting the latent multivariate Gaussian structure of the spatially distributed weather generator and making use of well-known statistical results that define conditional multivariate Gaussian distributions given known values for a subset of variables from the larger joint distribution. The primary focus is on precipitation, but the nonprecipitation variables in the weather generator are also amenable to gridding and to synchronization with nearby observed weather series. The motivating idea is to allow calibration of spatially distributed hydrological models consistent with the climate of the spatial weather generator, potentially allowing more realistic hydrological simulation, but the procedure may also be useful for interpolation of missing daily weather data.

  7. Tide-influenced sedimentary environments and facies

    SciTech Connect

    De Boer, P.L.; Van Gelder, A.; Nio, S.D.

    1988-01-01

    This volume contains examples of recent as well as fossil tide-influenced sedimentary facies. Studies of recent tidal processes and sediments provide an insight into the way in which tidal facies and sequences develop, and into the processes which are active. The studies performed on fossil rocks give information on one-to-one scale model experiments that have been executed by nature both relatively recently and in the distant past. In this work, the parallel presentation of papers on recent and fossil examples of tide-influenced sedimentary facies and environments follows the philosophy of comparative sedimentology, aiming at an understanding of both the past and the present, with the aim also, of forecasting future developments.

  8. Tides of global ice-covered oceans

    NASA Astrophysics Data System (ADS)

    Wunsch, Carl

    2016-08-01

    The tides of an ice-covered ocean are examined using a Cartesian representation of the elastic and fluid equations. Although unconstrained by any observations, the ocean tides of a Neoproterozoic "snowball" Earth could have been significantly larger than they are today. Time-mean tidal-residual circulations would then have been set up that are competitive with the circulation driven by geothermal heating. In any realistic configuration, the snowball Earth would have had an ice cover that is in the thin shell limit, but by permitting the ice thickness to become large, more interesting ice tidal response can be found, ones conceivably of application to bodies in the outer Solar System or hypothetical exoplanets. Little can be said concerning a reduction in tidal dissipation necessary to avoid a crisis in the history of the lunar orbit.

  9. Erratum: Resonant Tides in Close Orbiting Planets

    NASA Astrophysics Data System (ADS)

    Lubow, S. H.; Tout, C. A.; Livio, M.

    1999-06-01

    In the paper ``Resonant Tides in Close Orbiting Planets'' by S. H. Lubow, C. A. Tout, and M. Livio (ApJ, 484, 866 [1997]), there is a misprint in the abstract. The abstract states that ``the torque is exerted in a region where H/rp>>1....'' Instead, it should state that ``the torque is exerted in a region where H/rp<<1....''

  10. Apparent Relations Between Solar Activity and Solar Tides Caused by the Planets

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh

    2007-01-01

    A solar storm is a storm of ions and electrons from the Sun. Large solar storms are usually preceded by solar flares, phenomena that can be characterized quantitatively from Earth. Twenty-five of the thirty-eight largest known solar flares were observed to start when one or more tide-producing planets (Mercury, Venus, Earth, and Jupiter) were either nearly above the event positions (less than 10 deg. longitude) or at the opposing side of the Sun. The probability for this to happen at random is 0.039 percent. This supports the hypothesis that the force or momentum balance (between the solar atmospheric pressure, the gravity field, and magnetic field) on plasma in the looping magnetic field lines in solar corona could be disturbed by tides, resulting in magnetic field reconnection, solar flares, and solar storms. Separately, from the daily position data of Venus, Earth, and Jupiter, an 11-year planet alignment cycle is observed to approximately match the sunspot cycle. This observation supports the hypothesis that the resonance and beat between the solar tide cycle and nontidal solar activity cycle influences the sunspot cycle and its varying magnitudes. The above relations between the unpredictable solar flares and the predictable solar tidal effects could be used and further developed to forecast the dangerous space weather and therefore reduce its destructive power against the humans in space and satellites controlling mobile phones and global positioning satellite (GPS) systems.

  11. Deriving long-term sea level variations at tide gauge stations in Atlantic North America

    NASA Astrophysics Data System (ADS)

    Ince, E. S.; Sideris, M. G.; Rangelova, E.

    2009-05-01

    Tide gauge recording is an indispensable geodetic tool to study local sea level variations in coastal areas and mean sea level trends on a global scale. Combined with satellite altimetry sea surface heights or GNSS- derived ellipsoidal heights, tide gauge records have been used for deriving estimates of vertical crustal motion elsewhere. The objective of our paper is to study the capabilities of the method of singular spectrum analysis, which is generically related to empirical orthogonal functions/principal component analysis technique, to derive local long-term and secular sea level trends. This method allows one to extract any anomalous sea level signals, which is difficult to achieve by the conventional harmonic analysis. We use a set of tide gauge stations in Atlantic Canada and the USA extracted from the monthly PSMSL data base. To create continuous time series, we fill all time gaps by interpolating the main periodic and trend components of the sea level signal using the least squares harmonic analysis. We analyze all tide gauge time series simultaneously through singular value decomposition of the time-lagged series combined in a data trajectory matrix. This enables us to extract and separate the main modes of variability of the local sea level and to study only the long-term spatio-temporal patterns in the sea level variations. Our preliminary results show that the length of the tide gauge time series and the relative contribution of the signals to the total sea level variance are the two crucial factors that may preclude the separation of the local secular sea level fall or rise from any decadal sea level variability. The outcome of our study will be useful for combined satellite altimetry/TG/GRACE studies of sea level changes in the coastal areas, studies of vertical crustal motion due to postglacial rebound in the region, as well as the definition and realization of a dynamic reference surface for orthometric heights in North America.

  12. Tides and the Evolution of Planetary Habitability

    NASA Astrophysics Data System (ADS)

    Barnes, Rory; Raymond, Sean N.; Jackson, Brian; Greenberg, Richard

    2008-06-01

    Tides raised on a planet by the gravity of its host star can reduce the planet's orbital semi-major axis and eccentricity. This effect is only relevant for planets orbiting very close to their host stars. The habitable zones of low-mass stars are also close in, and tides can alter the orbits of planets in these locations. We calculate the tidal evolution of hypothetical terrestrial planets around low-mass stars and show that tides can evolve planets past the inner edge of the habitable zone, sometimes in less than 1 billion years. This migration requires large eccentricities (>0.5) and low-mass stars (≲0.35 M⊙). Such migration may have important implications for the evolution of the atmosphere, internal heating, and the Gaia hypothesis. Similarly, a planet that is detected interior to the habitable zone could have been habitable in the past. We consider the past habitability of the recently discovered, ˜5 M⊕ planet, Gliese 581 c. We find that it could have been habitable for reasonable choices of orbital and physical properties as recently as 2 Gyr ago. However, when constraints derived from the additional companions are included, most parameter choices that indicate past habitability require the two inner planets of the system to have crossed their mutual 3:1 mean motion resonance. As this crossing would likely have resulted in resonance capture, which is not observed, we conclude that Gl 581 c was probably never habitable.

  13. Downwelling wind, tides, and estuarine plume dynamics

    NASA Astrophysics Data System (ADS)

    Lai, Zhigang; Ma, Ronghua; Huang, Mingfen; Chen, Changsheng; Chen, Yong; Xie, Congbin; Beardsley, Robert C.

    2016-06-01

    The estuarine plume dynamics under a downwelling-favorable wind condition were examined in the windy dry season of the Pearl River Estuary (PRE) using the PRE primitive-equation Finite-Volume Community Ocean Model (FVCOM). The wind and tide-driven estuarine circulation had a significant influence on the plume dynamics on both local and remote scales. Specifically, the local effect of downwelling-favorable winds on the plume was similar to the theoretical descriptions of coastal plumes, narrowing the plume width, and setting up a vertically uniform downstream current at the plume edge. Tides tended to reduce these plume responses through local turbulent mixing and advection from upstream regions, resulting in an adjustment of the isohalines in the plume and a weakening of the vertically uniform downstream current. The remote effect of downwelling-favorable winds on the plume was due to the wind-induced estuarine sea surface height (SSH), which strengthened the estuarine circulation and enhanced the plume transport accordingly. Associated with these processes, tide-induced mixing tended to weaken the SSH gradient and thus the estuarine circulation over a remote influence scale. Overall, the typical features of downwelling-favorable wind-driven estuarine plumes revealed in this study enhanced our understanding of the estuarine plume dynamics under downwelling-favorable wind conditions.

  14. Global charts of ocean tide loading effects

    SciTech Connect

    Francis, O.; Mazzega, P. )

    1990-07-15

    Global ocean tide loading charts of the radial displacement, the potential divided by g (gravity acceleration), and the gravity effect have been computed using the 11 constituents M{sub 2}, S{sub 2}, N{sub 2}, K{sub 2}K{sub 1}, O{sub 1}, P{sub 1}, Q{sub 1}, M{sub f}, M{sub m}, S{sub s a} of Schwiderski's tidal model. These new charts have a resolution of 1{degree}{times}1{degree} on the continents as well as on the oceanic area. A description of Farrell's convolution method to compute the loading effects is given, and an estimate of the numerical errors leads to the conclusion that these global charts have a precision better than 2.5% independent of the accuracy of Schwiderski's maps. The current approximation of the loading effects by a proportionality relation with the local oceanic tides is also compared with Farrell's convolution method. Departures of several centimeters systematically appear, in particular over the continental shelves. The authors then show that the maps of the oceanic tides deduced from satellite altimetry could be corrected for the loading effect by an iterative computational procedure based on their algorithm of Farrell's convolution.

  15. Improving Coastal Tide Forecasts with Data Assimilation

    NASA Astrophysics Data System (ADS)

    Zaron, E. D.; Smith, S. R.; Martin, P.

    2012-12-01

    A model of the Yellow Sea is used as a prototype for improving tidal water levels in coastal ocean models. An incremental variational data assimilation method has been implemented in which a linear data-assimilative tidal model, OTIS, is used to compute model forcing corrections for a non-linear regional model derived from POM. Both OTIS and the POM-derived model are configured with identical 8km-resolution grids, and OTIS uses a bottom drag formulation linearized around the prior POM solution. Assimilated data consist of satellite altimeter data as well as harmonically analyzed tide gauge data, where half of the latter are withheld for parameter calibration. It is found that M2 tide error is reduced from 21cm to 12cm in the regional model, which compares favorably with the 11cm error for the linear OTIS solution. Smaller constituents are also improved to a lesser degree. In contrast, the alternative approach of using OTIS to provide boundary conditions for the POM-derived model yields M2 tides with an error of 20 to 40cm, depending on the version of the OTIS solution used.

  16. Weather in Your Life.

    ERIC Educational Resources Information Center

    Kannegieter, Sandy; Wirkler, Linda

    Facts and activities related to weather and meteorology are presented in this unit. Separate sections cover the following topics: (1) the water cycle; (2) clouds; (3) the Beaufort Scale for rating the speed and force of wind; (4) the barometer; (5) weather prediction; (6) fall weather in Iowa (sleet, frost, and fog); (7) winter weather in Iowa…

  17. Fun with Weather

    ERIC Educational Resources Information Center

    Yildirim, Rana

    2007-01-01

    This three-part weather-themed lesson for young learners connects weather, clothing, and feelings vocabulary. The target structures covered are: asking about the weather; comparing weather; using the modal auxiliary, should; and the question word, when. The lessons utilize all four skills and include such activities as going outside, singing,…

  18. Teaching Weather Concepts.

    ERIC Educational Resources Information Center

    Sebastian, Glenn R.

    Ten exercises based on the weather map provided in the national newspaper "U.S.A. Today" are used to teach intermediate grade students about weather. An overview describes the history of "U.S.A. Today," the format of the newspaper's weather map, and the map's suitability for teaching weather concepts. Specific exercises, which are briefly…

  19. Application of database technology to red tide remote sensing

    NASA Astrophysics Data System (ADS)

    Leng, Xiuhua; Zhang, Jie; Ma, Yi; Zhang, Hongliang

    2003-05-01

    The red tide spectrum database is the basis and prerequisite for red tide hyperspectral remote sensing, a technical support for the field investigation on red tide and the main technical measure for red tide data management and application. The data in the database mentioned in this paper come mainly from the red tide mesocosm experiment, and include the simultaneously collected biological, chemical, hydrographic and meteorological data besides the spectrum data of red tide dominant species. The database has not only the conventional functions for data query, retrieval and plotting, but also the algorithmic functions for the ground object spectrum data processing in the Visual FoxPro system environment and the biological information extraction using the ground object spectrum data. This system is not only an effective application system for detecting the red tide organism, identifying the red tide dominant species and analyzing the characteristic amount of red tide organism, but also a powerful tool for the marine environmental protection and the red tide disaster reduction in the future.

  20. Monitoring storm tide and flooding from Hurricane Isaac along the Gulf Coast of the United States, August 2012

    USGS Publications Warehouse

    McCallum, Brian E.; McGee, Benton D.; Kimbrow, Dustin R.; Runner, Michael S.; Painter, Jaime A.; Frantz, Eric R.; Gotvald, Anthony J.

    2012-01-01

    The U.S. Geological Survey (USGS) deployed a temporary monitoring network of water-level and barometric pressure sensors at 127 locations along the gulf coast from Alabama to Louisiana to record the timing, areal extent, and magnitude of hurricane storm tide and coastal flooding generated by Hurricane Isaac. This deployment was undertaken as part of a coordinated federal emergency response as outlined by the Stafford Act under a directed mission assignment by the Federal Emergency Management Agency. Storm tide, as defined by National Oceanic and Atmospheric Administration (NOAA; National Oceanic and Atmospheric Administration, 2008), is the water-level rise generated by a combination of storm surge and astronomical tide during a coastal storm. Hurricane Isaac initially made landfall on the coast of Louisiana in Plaquemines Parish on August 28, 2012, as a Category 1 hurricane on the Saffir–Simpson Hurricane Wind Scale (National Weather Service, 1974) and then stalled over southern Louisiana for several days, causing prolonged storm-tide impacts. A total of 188 water-level and wave-height sensors were deployed at 127 locations during August 27–28 prior to landfall. More than 90 percent of the sensors and all high-water marks (HWMs) were recovered and surveyed to North American Vertical Datum of 1988 (NAVD 88) within 7 days of the Isaac landfall. Only a handful of sensors in the Plaquemines Parish area of Louisiana could not be retrieved until weeks later due to prolonged flooding in the area. Data collected from this event can be used to evaluate the performance of storm-tide models for maximum and incremental water level and flood extent and the site-specific effects of storm tide on natural and anthropogenic features of the environment.

  1. Harmonic analysis of tides and tidal currents in South San Francisco Bay, California

    USGS Publications Warehouse

    Cheng, R.T.; Gartner, J.W.

    1985-01-01

    Water level observations from tide stations and current observations from current-meter moorings in South San Francisco Bay (South Bay), California have been harmonically analysed. At each tide station, 13 harmonic constituents have been computed by a least-squares regression without inference. Tides in South Bay are typically mixed; there is a phase lag of approximately 1 h and an amplification of 1??5 from north to south for a mean semi-diurnal tide. Because most of the current-meter records are between 14 and 29 days, only the five most important harmonics have been solved for east-west and north-south velocity components. The eccentricity of tidal-current ellipse is generally very small, which indicates that the tidal current in South Bay is strongly bidirectional. The analyses further show that the principal direction and the magnitude of tidal current are well correlated with the basin bathymetry. Patterns of Eulerian residual circulation deduced from the current-meter data show an anticlockwise gyre to the west and a clockwise gyre to the east of the main channel in the summer months due to the prevailing westerly wind. Opposite trends have been observed during winter when the wind was variable. ?? 1985.

  2. Nonlinear Tides in Close Binary Systems

    NASA Astrophysics Data System (ADS)

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-06-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' >~ 10-100 M ⊕ at orbital periods P ≈ 1-10 days. The nearly static "equilibrium" tidal distortion is, however, stable to parametric resonance except for solar binaries with P <~ 2-5 days. (2) For companion masses larger than a few Jupiter masses, the dynamical tide causes short length scale waves to grow so rapidly that they must be treated as traveling waves, rather than standing waves. (3) We show that the global three-wave treatment of parametric instability typically used in the astrophysics literature does not yield the fastest-growing daughter modes or instability threshold in many cases. We find a form of parametric instability in which a single parent wave excites a very large number of daughter waves (N ≈ 103[P/10 days] for a solar-type star) and drives them as a single coherent unit with growth rates that are a factor of ≈N faster than the

  3. NONLINEAR TIDES IN CLOSE BINARY SYSTEMS

    SciTech Connect

    Weinberg, Nevin N.; Arras, Phil; Quataert, Eliot; Burkart, Josh

    2012-06-01

    We study the excitation and damping of tides in close binary systems, accounting for the leading-order nonlinear corrections to linear tidal theory. These nonlinear corrections include two distinct physical effects: three-mode nonlinear interactions, i.e., the redistribution of energy among stellar modes of oscillation, and nonlinear excitation of stellar normal modes by the time-varying gravitational potential of the companion. This paper, the first in a series, presents the formalism for studying nonlinear tides and studies the nonlinear stability of the linear tidal flow. Although the formalism we present is applicable to binaries containing stars, planets, and/or compact objects, we focus on non-rotating solar-type stars with stellar or planetary companions. Our primary results include the following: (1) The linear tidal solution almost universally used in studies of binary evolution is unstable over much of the parameter space in which it is employed. More specifically, resonantly excited internal gravity waves in solar-type stars are nonlinearly unstable to parametric resonance for companion masses M' {approx}> 10-100 M{sub Circled-Plus} at orbital periods P Almost-Equal-To 1-10 days. The nearly static 'equilibrium' tidal distortion is, however, stable to parametric resonance except for solar binaries with P {approx}< 2-5 days. (2) For companion masses larger than a few Jupiter masses, the dynamical tide causes short length scale waves to grow so rapidly that they must be treated as traveling waves, rather than standing waves. (3) We show that the global three-wave treatment of parametric instability typically used in the astrophysics literature does not yield the fastest-growing daughter modes or instability threshold in many cases. We find a form of parametric instability in which a single parent wave excites a very large number of daughter waves (N Almost-Equal-To 10{sup 3}[P/10 days] for a solar-type star) and drives them as a single coherent unit with

  4. What can earth tide measurements tell us about ocean tides or earth structure?

    NASA Technical Reports Server (NTRS)

    Baker, T. F.

    1978-01-01

    Current experimental problems in Earth tides are reviewed using comparisons of tidal gravity and tilt measurements in Europe with loading calculations are examples. The limitations of present day instrumentation and installation techniques are shown as well as some of the ways in which they can be improved. Many of the geophysical and oceanographic investigations that are possible with Earth tide measurements are discussed with emphasis on the percentage accuracies required in the measurements in order to obtain new information about Earth or its oceans.

  5. Surface manifestation of internal tides generated near Hawaii

    NASA Astrophysics Data System (ADS)

    Ray, Richard D.; Mitchum, Gary T.

    Analysis of Topex/Poseidon satellite altimetry reveals short-wavelength fluctuations in the ocean surface tide that are attributable to internal tides. A significant fraction of the semidiurnal internal tide generated at the Hawaiian Ridge is evidently phase-locked to the astronomical potential and can modulate the amplitude of the surface tide by ∼5 cm. The internal tide is thus easily mapped along satellite groundtracks, and it is found to be spatially coherent over great distances, with waves propagating well over 1000 km from the Hawaiian Ridge before decaying below noise level. Both first and second baroclinic modes are observed in both the M2 (lunar) and S2 (solar) tides. The high space-time coherence is in sharp contrast to what is often inferred from current-meter observations, but it confirms recent speculations from an acoustic experiment north of Hawaii.

  6. Cultural Implications of Out-of-Phase Weather across northern Alaska after 500 CE: Regional Variability during the Medieval Climate Anomaly and Little Ice Age

    NASA Astrophysics Data System (ADS)

    Mason, O. K.; Alix, C. M.; Bigelow, N. H.; Hoffecker, J. F.

    2014-12-01

    From a global perspective, a diverse mélange of paleoclimate data reveal that Northwest Alaska is partially out of phase with northwest Europe, witnessing cooler periods during the Medieval Climate Anomaly ca. CE 1000 and warmer conditions in the 16th and 17th centuries. The search for climatic forcers in northern Alaska relies on integration of data drawn from tree-rings, lacustrine varves and moraines, diatoms, beach ridges and dunes. At Cape Espenberg, northern Seward Peninsula, a 1500-year reconstruction of settlement, landscape evolution and climatic variability employs >100 14C ages from accreting dunes with shell-laden storm beds, intercalated driftwood and superimposed soils, archaeological sites and marsh peats within swale ponds. Large storms occurred along the Chukchi Sea from Cape Espenberg and Deering (Kotzebue Sound) to Point Barrow prior to 1000 CE, and at decadal intervals during the Little Ice Age (LIA) from 1300 to 1700. Architecural driftwood logs from several excavated houses capped by sand dunes yield several 14C dated floating chronologies covering intervals from 700 to 1700, suggest the identification of cooler intervals 800 to 1000 and intermittently after 1300. Peat aggradation followed isolation from the sea from 500 onward, and was interrupted by two pulses of fresh water, one ca. 1300 and a second ca. 1800, with diatoms suggesting relative aridity during the LIA. The occupation history of Cape Espenberg generally follows dune growth, and may be inversely related to cooler temperatures.

  7. Analysis of the most recent data of Cascais Tide Gauge

    NASA Astrophysics Data System (ADS)

    Antunes, Carlos; Taborda, Rui; Mendes, Virgílio B.

    2010-05-01

    In order to meet international standards and to integrate sea level changes and tsunami monitoring networks, Cascais tide gauge, one of the oldest in the world, has been upgraded in 2003 with new acoustic equipment with digital data acquisition, temperature and air-pressure sensors, and internet connection for real time data. The new tide gauge is located very close to the old analogical gauge, which is still working. Datum links between both gauges and the permanent GPS station of Cascais were made and height differences between gauges and the GPS station have been monitored to verify site stability and to estimate the absolute vertical velocity of the site, and therefore, the absolute sea level changes. Tide gauge data from 2000 to 2009 has been analyzed and relative and absolute sea level rise rates have been estimated. The estimation of sea level rise rate with the short baseline of 10 years is made with the daily mean sea level data corrected from the inverse barometric effect. The relative sea level trend is obtained from a 60-day moving average run over the corrected daily mean sea level. The estimated rate has shown greater stability in contrast to the analysis of daily mean sea level raw data, which shows greater variability and uncertainty. Our results show a sea level rise rate of 2.6 mm/year (± 0.3 mm/year), higher than previous rates (2.1 mm/year for 1990 decade and 1.6 mm/year from 1920 to 2000), which is compatible with a sea level rise acceleration scenario. From the analysis of Cascais GPS data, for the period 1990.0 to 2010.0 we obtain an uplift rate of 0.3 mm/year leading to an absolute sea level rise of 2.9 mm/year for Cascais, under the assumption, as predicted by the ICE-5G model, that Cascais has no vertical displacement caused by the post-glacial isostatic adjustment.

  8. Long-period perturbations in Starlette orbit and tide solution

    SciTech Connect

    Cheng, M.K.; Shum, C.K.; Eanes, R.J.; Schutz, B.E.; Tapley, B.D. )

    1990-06-10

    Continuous and dynamically consistent orbits have been computed using satellite laser ranging (SLR) data to Starlette for one-year period during 1976 and 1977 and the three-year period from 1983 through 1985. A low degree and order ocean tide solution, consisting of a total of 66 tidal parameters from 14 tidal constituents, was obtained in a combined solution using both the one-and three-year Starlette orbits. Yearly values for the second-degree annual tides, S{sub a}, which produce seasonal variations on the Starlette node, were obtained also. These variations were found to have year-to-year fluctuations of more than 25% about the mean value and produced significant long-period perturbations in the Starlette orbit. The Starlette tide solution is in good agreement with the Schwiderski tide solutions and with other satellite solutions, including multi-satellite tide solutions. The average uncertainties are approximately 0.1 cm for the estimated semidiurnal and diurnal tides and 0.4 cm for the long-period tides. The discrepancies of effective k{sub 2} inferred from the Starlette tide solution and other tide solutions are less than 0.01. The tide solutions were evaluated using orbit fits of a three-year LAGEOS and a one-year Starlette long arc. The results indicate that the Starlette tide solution produces significantly improved orbit fits for both LAGEOS and Starlette. The uncertainties for the estimated tide model coefficients were used to predict tidal errors for the LAGEOS orbit and were found to be consistent with the apparent tidal errors present in this orbit. The computed secular change in the Moon's mean motion due to tidal dissipation is {minus}24.8 {plus minus} 0.8 arc second/century{sup 2}, which is in good agreement with the results obtained from other investigations.

  9. Irrigation as an Adaptation Strategy to Climate Change: The Relative Influence of Groundwater and Canal Irrigation on Winter Crop Production and its Sensitivity to Weather Variability in India

    NASA Astrophysics Data System (ADS)

    Jain, M.; Fishman, R.; Mondal, P.; Galford, G. L.; Naeem, S.; Modi, V.; DeFries, R. S.

    2014-12-01

    India is a hotspot for food security issues over the upcoming decades, due to increasing population pressures, groundwater depletion, and climate change. Investing in additional irrigation infrastructure may bolster food security, however, the relative influence of different types of irrigation (e.g. groundwater versus canal) on agricultural production remains unclear. One reason that the relative impact of different irrigation strategies on agricultural production has not been analyzed across India is because national-scale data on crop production and the types of irrigation technologies used are typically available at too coarse of spatial and temporal resolutions to answer this question adequately. Thus, we develop a novel algorithm to map cropped area across India at a 1 x 1 km scale using MODIS satellite data, and link these high-resolution cropped area maps with village-level data (n = 600,000) on irrigation. This allowed us to assess the relative impact of groundwater (i.e. dug, shallow, and deep wells) and canal irrigation (i.e. surface lift and flow canals) on winter cropped area and its sensitivity to rainfall across India at the village-scale from 2000 to 2006. We find that deep well irrigation is both associated with the greatest amount of winter cropped area, and is also the least sensitive to monsoon and winter rainfall variability. However, the effectiveness of deep well irrigation varies across India, with the greatest benefits seen in the regions that are most at risk for losing groundwater as a possible source of irrigation over the upcoming decades (e.g. Northwest India). This work highlights the need to develop ways to use remaining groundwater more efficiently (e.g. drip irrigation, less water-intensive crops) given that canal irrigation is not an adequate substitute, particularly in the regions that are facing the greatest levels of groundwater depletion.

  10. Erosion risk in the northern Gulf of Mexico - the effects of climate and weather

    NASA Astrophysics Data System (ADS)

    Wahl, Thomas; Plant, Nathaniel G.; Long, Joseph W.

    2016-04-01

    Oceanographic variables such as mean sea level, tides, storm surges, and waves are drivers of erosion, and they act on different time scales ranging from hours (associated with weather) to seasonal and decadal variations and trends (associated with climate). Here we explore how the related sea-state conditions affect the erosion risk in the northern Gulf of Mexico for past and future climate scenarios. From the climate perspective we find that long-term trends in the relevant variables have caused an increase of ~30% in the erosion risk since the 1980s; at least half of this increase was due to changes in the wave climate. In the next decades, sea level rise will likely become the dominating driver and may, in combination with ongoing changes in the wave climate (and depending on the emission scenario), escalate the erosion risk by up to 300% over the next 30 years. We also find significant changes in the seasonal cycles of sea level and significant wave height, which have in combination caused a considerable increase of the erosion risk in summer and decrease in winter (superimposed onto the long-term trends). The influence of weather is assessed with a copula-based multivariate sea storm model in a Monte-Carlo framework; i.e. we simulate hundreds of thousands of artificial but physically consistent sea-state conditions to quantify how different our understanding of the present day erosion risk would be if we had seen more or less extreme combinations of the different sea-state parameters over the last three decades. We find, for example, that total water levels (tide + surge + wave run-up) associated with 100-year return periods may be underestimated by up to 30% and that the average number of impact hours - when total water levels exceeded the height of the dune toe (collision) or dune crest (overwash) - could have been up to 50% higher than what we inferred based on the actually observed oceanographic conditions. Assessing erosion risk in such a probabilistic

  11. How climate and weather affect the erosion risk in the northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Wahl, T.; Plant, N. G.

    2015-12-01

    Oceanographic variables such as mean sea level, tides, storm surges, and waves are drivers of erosion, and they act on different time scales ranging from hours (associated with weather) to seasonal and decadal variations and trends (associated with climate). Here we explore how the related sea-state conditions affect the erosion risk in the northern Gulf of Mexico for past and future climate scenarios. From the climate perspective we find that long-term trends in the relevant variables have caused an increase of ~30% in the erosion risk since the 1980s; at least half of this increase was due to changes in the wave climate. In the next decades, sea level rise will likely become the dominating driver and may, in combination with ongoing changes in the wave climate (and depending on the emission scenario), escalate the erosion risk by up to 300% over the next 30 years. We also find significant changes in the seasonal cycles of sea level and significant wave height, which have in combination caused a considerable increase of the erosion risk in summer and decrease in winter (superimposed onto the long-term trends). The influence of weather is assessed with a copula-based multivariate sea storm model in a Monte-Carlo framework; i.e. we simulate hundreds of thousands of artificial but physically consistent sea-state conditions to quantify how different our understanding of the present day erosion risk would be if we had seen more or less extreme combinations of the different sea-state parameters over the last three decades. We find, for example, that total water levels (tide + surge + wave run-up) associated with 100-year return periods may be underestimated by up to 30% and that the average number of impact hours - when total water levels exceeded the height of the dune toe (collision) or dune crest (overwash) - could have been up to 50% higher than what we inferred based on the actually observed oceanographic conditions. Assessing erosion risk in such a probabilistic

  12. Oceanic tide maps and spherical harmonic coefficients from Geosat altimetry

    NASA Technical Reports Server (NTRS)

    Cartwright, D. E.; Ray, R. D.; Sanchez, B. V.

    1991-01-01

    Maps and tables for the global ocean tides, 69 degree N to 68 degree S, derived from two years of Geosat altimetry are presented. Global maps of local and Greenwich admittance of the (altimetric) ocean tide, and maps of amplitude and Greenwich phase lag of the ocean tide are shown for M(sub 2), S(sub 2), N(sub 2), O(sub 1), and K(sub 1). Larger scale maps of amplitude and phases are also shown for regional areas of special interest. Spherical harmonic coefficients of the ocean tide through degree and order 8 are tabulated for the six major constituents.

  13. Precise Comparisons of Bottom-Pressure and Altimetric Ocean Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.

    2013-01-01

    A new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean. To maximize precision of estimated tides, only stations with long time series are used; median time series length is 567 days. Geographical coverage is considerably improved by use of the international tsunami network, but coverage in the Indian Ocean and South Pacific is still weak. As a tool for assessing global ocean tide models, the data set is considerably more reliable than older data sets : the root-mean-square difference with a recent altimetric tide model is approximately 5 mm for the M2 constituent. Precision is sufficiently high to allow secondary effects in altimetric and bottom-pressure tide differences to be studied. The atmospheric tide in bottom pressure is clearly detected at the S1, S2, and T2 frequencies. The altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide. Models of the solid body tide can also be constrained. The free corenutation effect in the K1 Love number is easily detected, but the overall estimates are not as accurate as a recent determination with very long baseline interferometry.

  14. Pilot weather advisor

    NASA Technical Reports Server (NTRS)

    Kilgore, W. A.; Seth, S.; Crabill, N. L.; Shipley, S. T.; Graffman, I.; Oneill, J.

    1992-01-01

    The results of the work performed by ViGYAN, Inc., to demonstrate the Pilot Weather Advisor cockpit weather data system using a broadcast satellite communication system are presented. The Pilot Weather Advisor demonstrated that the technical problems involved with transmitting significant amount of weather data to an aircraft in-flight or on-the-ground via satellite are solvable with today's technology. The Pilot Weather Advisor appears to be a viable solution for providing accurate and timely weather information for general aviation aircraft.

  15. Weather Information System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    WxLink is an aviation weather system based on advanced airborne sensors, precise positioning available from the satellite-based Global Positioning System, cockpit graphics and a low-cost datalink. It is a two-way system that uplinks weather information to the aircraft and downlinks automatic pilot reports of weather conditions aloft. Manufactured by ARNAV Systems, Inc., the original technology came from Langley Research Center's cockpit weather information system, CWIN (Cockpit Weather INformation). The system creates radar maps of storms, lightning and reports of surface observations, offering improved safety, better weather monitoring and substantial fuel savings.

  16. Numerical study of solute transport in shallow beach aquifers subjected to waves and tides

    NASA Astrophysics Data System (ADS)

    Geng, Xiaolong; Boufadel, Michel C.

    2015-02-01

    A numerical study was conducted to investigate the fate of solute in a laboratory beach in response to waves and tides. A new temporal upscaling approach labeled "net inflow" was introduced to address impacts of waves on solute transport within beaches. Numerical simulations using a computational fluid dynamic model were used as boundary conditions for the two-dimensional variably saturated flow and solute transport model MARUN. The modeling approach was validated against experimental data of solute transport due to waves and tides. Exchange fluxes across the beach face and subsurface solute transport (e.g., trajectory, movement speed, and residence time) were quantified. Simulation results revealed that waves increased the exchange fluxes, and engendered a wider exchange flux zone along the beach surface. Compared to tide-only forcing, waves superimposed on tide caused the plume to be deeper into the beach, and to migrate more seaward. The infiltration into the beach was found to be directly proportional to the general hydraulic gradient in the beach and inversely proportional to the matrix retention (or capillary) capacity. The simulations showed that a higher inland water table would attenuate wave-caused seawater infiltration, which might impact beach geochemical processes (e.g., nutrient recycle and redox condition), especially at low tide zone. The concept of biochemical residence time maps (BRTM) was introduced to account for the net effect of limiting concentration of chemicals on biochemical reactions. It was found that waves shifted the BRTMs downward and seaward in the beach, and subsequently they engendered different biochemical conditions within the beach.

  17. Mapping M2 Internal Tides Using a Data-Assimilative Reduced Gravity Mode

    NASA Astrophysics Data System (ADS)

    Egbert, G. D.; Erofeeva, S.

    2014-12-01

    We have developed data assimilation methods for mapping low-mode phase-locked internal tides from altimetry data, using a reduced gravity (RG) approach. Dynamical equations are derived following the approach of Griffiths and Grimshaw (2007), with the vertical dependence of pressure and velocities in the linear Boussinesq 3D equations expanded in basis functions derived from local 1D modes for a stratified ocean. This results in a system of coupled 2D PDEs for the coefficients of the modal expansion. Excluding coupling terms between modes (which arise in the presence of variable bottomt opography) the resulting equations for each mode are analogous to the usual shallow water equations for the barotropic tide. With modest changes to the OSU tidal inversion software (OTIS) an assimilation scheme for this linear model is readily implemented. The coupling terms can be used to derive the forcing (by the barotropic tide), and also can be used to quantify the component of model error associated with unmodeled topographic scattering. Because the inversion yields currents as well as elevations, mode energy fluxes can obtained with minimal further calculation. Relatively high spatial resolution (at least 1/30 degree) is required for the RG dynamical model, so the inversion must be done in modest sized overlapping patches, which can then be merged to obtain global maps of phase-locked low-mode internal tides. To obtain reliable results some care with preliminary data processing has proved necessary, including correction for lower frequency SSH variations in areas of strong mesoscale activity, and filtering to reduce Long wavelength error, especially in ERS/Envisat data. Because the assimilation essentially derives dynamically consistent spatio-temporal basis functions for data fitting, the RG scheme may also provide a means to better quantify at least slowly varying incoherent internal tides.

  18. Tides and the evolution of planetary habitability.

    PubMed

    Barnes, Rory; Raymond, Sean N; Jackson, Brian; Greenberg, Richard

    2008-06-01

    Tides raised on a planet by the gravity of its host star can reduce the planet's orbital semi-major axis and eccentricity. This effect is only relevant for planets orbiting very close to their host stars. The habitable zones of low-mass stars are also close in, and tides can alter the orbits of planets in these locations. We calculate the tidal evolution of hypothetical terrestrial planets around low-mass stars and show that tides can evolve planets past the inner edge of the habitable zone, sometimes in less than 1 billion years. This migration requires large eccentricities (>0.5) and low-mass stars ( less or similar to 0.35 M(circle)). Such migration may have important implications for the evolution of the atmosphere, internal heating, and the Gaia hypothesis. Similarly, a planet that is detected interior to the habitable zone could have been habitable in the past. We consider the past habitability of the recently discovered, approximately 5 M(circle) planet, Gliese 581 c. We find that it could have been habitable for reasonable choices of orbital and physical properties as recently as 2 Gyr ago. However, when constraints derived from the additional companions are included, most parameter choices that indicate past habitability require the two inner planets of the system to have crossed their mutual 3:1 mean motion resonance. As this crossing would likely have resulted in resonance capture, which is not observed, we conclude that Gl 581 c was probably never habitable. PMID:18598142

  19. Numerical simulation of tides in Ontario Lacus

    NASA Astrophysics Data System (ADS)

    Vincent, David; Karatekin, Ozgür

    2015-04-01

    Hydrocarbons liquid filled lakes has been recently detected on Titan's surface. Most of these lakes are located in the northern latitudes but there is a substantial lake in the southern latitudes: Ontario Lacus. This lake gets our attention because of possible shoreline changes suggested by Cassini flybys over Ontario Lacus between September 2005 (T7) et January 2010 (T65). The shoreline changes could be due to evaporation-precipitation processes but could also be a consequence of tides. Previous studies showed that the maximal tidal amplitudes of Ontario Lacus would be about 0.2m (for an uniform bathymetry of 20m). In this study we simulate tidal amplitude and currents with SLIM (Second-generation Louvain-la-Neuve Ice-ocean Model, http://sites.uclouvain.be/slim/ ) which resolves 2D shallow water equation on an unstructured mesh. Unstructured mesh prevents problems like mesh discontinuities at poles and allows higher accuracy at some place like coast or straits without drastically increasing computing costs. The tide generating force modeled in this work is the gradient of tidal potential due to titan's obliquity and titan's orbital eccentricity around Saturn (other contribution such as sun tide generating force are unheeded). The uncertain input parameters such as the wind direction and amplitude, bottom friction and thermo-physical properties of hydrocarbons liquids are varied within their expected ranges. SAR data analysis can result in different bathymetry according to the method. We proceed simulations for different bathymetries: tidal amplitudes doesn't change but this is not the case for tidal currents. Using a recent bathymetry deduced from most recent RADAR/SAR observations and a finer mesh, the peak-to peak tidal amplitudes are calculated to be up to 0.6 m. which is more than a factor two larger than the previous results. The maximal offshore tidal currents magnitude is about 0.06 m/s.

  20. Red Tide Strands South African Rock Lobsters

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Although some red tides form a healthy part of phytoplankton production, recurrent harmful or toxic blooms also occur, with results depending upon the type of plankton and on atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached themselves during February 2002, when the decay of dense blooms of phytoplankton caused a rapid reduction in the oxygen concentration of nearshore waters. The lobsters (or crayfish, as they are known locally) moved toward the breaking surf in search of oxygen, but were stranded by the retreating tide. The Multi-angle Imaging SpectroRadiometer's nadir camera acquired these red, green, blue composites on February 2 and 18, 2002, during Terra orbits 11315 and 11548. The colors have been accentuated to highlight the bloom, and land and water have been enhanced separately. The two views show the shoreward migration of the algal bloom. Each image represents an area of about 205 kilometers x 330 kilometers. Elands Bay is situated near the mouth of the Doring River, about 75 kilometers northeast of the jutting Cape Columbine. The term 'red tide' is used to refer to a number of different types of phytoplankton blooms of various hues. The wine color of certain parts of this bloom are consistent with the ciliate species Mesodinium rubrum, which has been associated with recurring harmful algal blooms along the Western Cape coast. Under these conditions, the lobsters are not poisoned. During the recent event, government and military staff transported as many of the living lobsters as possible to areas that were less affected by the red tide. At the same time, people came from across South Africa to gather the undersized creatures for food. The effects of the losses on the maritime economy are expected to be felt over the next few years. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra

  1. Red Tide Strands South African Rock Lobsters

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Although some red tides form a healthy part of phytoplankton production, recurrent harmful or toxic blooms also occur, with results depending upon the type of plankton and on atmospheric and oceanic conditions. At Elands Bay in South Africa's Western Cape province, about 1000 tons of rock lobsters beached themselves during February 2002, when the decay of dense blooms of phytoplankton caused a rapid reduction in the oxygen concentration of nearshore waters. The lobsters (or crayfish, as they are known locally) moved toward the breaking surf in search of oxygen, but were stranded by the retreating tide.

    The Multi-angle Imaging SpectroRadiometer's nadir camera acquired these red, green, blue composites on February 2 and 18, 2002, during Terra orbits 11315 and 11548. The colors have been accentuated to highlight the bloom, and land and water have been enhanced separately. The two views show the shoreward migration of the algal bloom. Each image represents an area of about 205 kilometers x 330 kilometers. Elands Bay is situated near the mouth of the Doring River, about 75 kilometers northeast of the jutting Cape Columbine.

    The term 'red tide' is used to refer to a number of different types of phytoplankton blooms of various hues. The wine color of certain parts of this bloom are consistent with the ciliate species Mesodinium rubrum, which has been associated with recurring harmful algal blooms along the Western Cape coast. Under these conditions, the lobsters are not poisoned. During the recent event, government and military staff transported as many of the living lobsters as possible to areas that were less affected by the red tide. At the same time, people came from across South Africa to gather the undersized creatures for food. The effects of the losses on the maritime economy are expected to be felt over the next few years.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington

  2. TEACHING PHYSICS: The tides - a neglected topic

    NASA Astrophysics Data System (ADS)

    Härtel, Hermann

    2000-01-01

    The lunar tides are generated by the movement of the Earth through the non-homogeneous gravitational field of the Moon while circling around the centre of mass of the Moon and Earth and simultaneously rotating around its own axis. This truly dynamic system is difficult to explain when the explanation is restricted to print media. Computer simulations, where these processes can be visualized directly, can be used to add value, thus opening new paths for a more distinct analysis and increased learning results.

  3. Winter Weather: Indoor Safety

    MedlinePlus

    ... page: About CDC.gov . Natural Disasters and Severe Weather Earthquakes Being Prepared Emergency Supplies Home Hazards Indoor ... Heat Prevention Guide (Part 3 of 3) Hot Weather Tips Heat Stress in Older Adults FAQs Extreme ...

  4. Winter Weather Emergencies

    MedlinePlus

    Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

  5. Abiotic factors influencing biomass accumulation of green tide causing Ulva spp. on Pyropia culture rafts in the Yellow Sea, China.

    PubMed

    Keesing, John K; Liu, Dongyan; Shi, Yajun; Wang, Yujue

    2016-04-15

    Annually recurrent green-tides in the Yellow Sea have been shown to result from direct disposal into the sea of fouling Ulva from Pyropia aquaculture. The role abiotic factors play in Ulva biomass accumulation on rafts was studied to find ways to mitigate this problem. Dissolved inorganic nitrogen (DIN) was very high at all sites, but the highest Ulva biomass was associated with the lowest DIN and anthropogenic N. Under luxuriant background nutrient conditions, variability in temperature and periods of emersion, rather than pH, light and salinity determined Ulva biomass. Two dominant species of Ulva displayed differing tolerances to temperature and desiccation which helped explain why Ulva prolifera dominates floating green-tides. Rather than trying to mitigate green-tides only by reducing nutrient pollution, an earlier harvest of Pyropia in southern Jiangsu Province especially before temperatures increase greatly above 10°C during April, could reduce the biomass of U. prolifera disposed from rafts. PMID:26936121

  6. Impact of atmospheric tides simulated in a chemistryclimate model on sub-diurnal variations in UT1

    NASA Astrophysics Data System (ADS)

    Kadow, C.; Dobslaw, H.; Matthes, K.; Thomas, M.

    2012-12-01

    Sub-diurnal variations in Earth rotation parameters as obtained from time-series of space geodetic observations contain substantial variability even after correcting for the effects of oceanic tides. These residuals are in particular apparent at frequencies of 1, 2 and 3 cycles per solar day, where atmospheric tides, principally excited by water vapor absorption and ozone heating in the middle atmosphere, are known to occur. By means of hourly data of the chemistry-climate model WACCM, the potential of atmospheric tides on the excitation of UT1 variations is re-assessed. Tidal signals are separated into migrating and non-migrating zonal waves for individual height levels. Only standing waves of wavenumber zero are found to be effective in exciting UT1 variations, which are subsequently discussed in terms of their characteristic surface pressure and vertically varying wind amplitudes.

  7. Convective Weather Avoidance with Uncertain Weather Forecasts

    NASA Technical Reports Server (NTRS)

    Karahan, Sinan; Windhorst, Robert D.

    2009-01-01

    Convective weather events have a disruptive impact on air traffic both in terminal area and in en-route airspaces. In order to make sure that the national air transportation system is safe and efficient, it is essential to respond to convective weather events effectively. Traffic flow control initiatives in response to convective weather include ground delay, airborne delay, miles-in-trail restrictions as well as tactical and strategic rerouting. The rerouting initiatives can potentially increase traffic density and complexity in regions neighboring the convective weather activity. There is a need to perform rerouting in an intelligent and efficient way such that the disruptive effects of rerouting are minimized. An important area of research is to study the interaction of in-flight rerouting with traffic congestion or complexity and developing methods that quantitatively measure this interaction. Furthermore, it is necessary to find rerouting solutions that account for uncertainties in weather forecasts. These are important steps toward managing complexity during rerouting operations, and the paper is motivated by these research questions. An automated system is developed for rerouting air traffic in order to avoid convective weather regions during the 20- minute - 2-hour time horizon. Such a system is envisioned to work in concert with separation assurance (0 - 20-minute time horizon), and longer term air traffic management (2-hours and beyond) to provide a more comprehensive solution to complexity and safety management. In this study, weather is dynamic and uncertain; it is represented as regions of airspace that pilots are likely to avoid. Algorithms are implemented in an air traffic simulation environment to support the research study. The algorithms used are deterministic but periodically revise reroutes to account for weather forecast updates. In contrast to previous studies, in this study convective weather is represented as regions of airspace that pilots

  8. Europa Tide Inversion from REASON Altimetry

    NASA Astrophysics Data System (ADS)

    Haynes, M.; Schroeder, D. M.; Steinbrügge, G.; Bills, B. G.

    2015-12-01

    Determining the amplitude of Europa's tides is central to understanding its ice shell and subsurface ocean. We assess the accuracy of retrieving the tidal amplitude solely using altimetry profiles produced by the REASON instrument (Radar for Europa Assessment and Sounding: Ocean to Near-surface), selected for the Europa Clipper mission. We investigate retrieval of the first Love number, h2, by inverting the entire set of altimetric ground tracks over the life of the mission. The inversion simultaneously estimates h2, long-wavelength topography, and spacecraft orbit parameters. In its simplest form, the inversion is quite robust: the time and location of the ground track uniquely fixes the phase of the sampled tide, where surface roughness acts as noise to be averaged out. In addition, we make an initial evaluation of altimetric biases that arise from known and hypothesized Europa topography using surface point target simulations. Overall, we find that the altimeter alone is capable of retrieving the first tidal Love number with accuracy sufficient to observationally constrain ice-shell thickness.

  9. Nonlinear Tides in Coalescing Binary Neutron Stars

    NASA Astrophysics Data System (ADS)

    Weinberg, Nevin

    2016-03-01

    Coalescing binary neutron stars are among the most promising sources for ground-based gravitational wave detectors such as Advanced LIGO. Tidal interactions in such systems extract energy from the orbit and, at some level, modify the gravitational wave signal. Previous studies found that tidal effects are probably too small to be detected from individual systems with LIGO. However, these studies typically assumed that the tide can be treated as a linear perturbation to the star. I will show that the linear approximation is invalid even during the early stages of inspiral and that nonlinear fluid effects in the form of tide-internal wave interactions become important around the time the binary first enters LIGO's bandpass (at gravitational wave frequencies around 30 Hz). Although the precise influence of nonlinear fluid effects is not yet well constrained, I will show that they may significantly modify the gravitational wave signal and electromagnetic emission from coalescing binary neutron stars. This research was supported by NASA Grant NNX14AB40G.

  10. American Weather Stories.

    ERIC Educational Resources Information Center

    Hughes, Patrick

    Weather has shaped United States' culture, national character and folklore; at times it has changed the course of history. The seven accounts compiled in this publication highlight some of the nation's weather experiences from the hurricanes that threatened Christopher Columbus to the peculiar run of bad weather that has plagued American…

  11. Weather Fundamentals: Meteorology. [Videotape].

    ERIC Educational Resources Information Center

    1998

    The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) looks at how meteorologists gather and interpret current weather data collected from sources…

  12. Aviation weather services

    NASA Technical Reports Server (NTRS)

    Sprinkle, C. H.

    1983-01-01

    The primary responsibilities of the National Weather Service (NWS) are to: provide warnings of severe weather and flooding for the protection of life and property; provide public forecasts for land and adjacent ocean areas for planning and operation; and provide weather support for: production of food and fiber; management of water resources; production, distribution and use of energy; and efficient and safe air operations.

  13. Severe Weather Perceptions.

    ERIC Educational Resources Information Center

    Abrams, Karol

    Severe weather is an element of nature that cannot be controlled. Therefore, it is important that the general public be aware of severe weather and know how to react quickly and appropriately in a weather emergency. This study, done in the community surrounding the Southern Illinois University at Carbondale, was conducted to compile and analyze…

  14. Weather and climate applications for rangeland restoration planning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rangeland ecosystems generally have an arid or semi-arid climatology, and are characterized by relatively high variability in seasonal and annual patterns of precipitation. Weather variability during seedling establishment is universally acknowledged as a principal determinant of rangeland seeding...

  15. Modelling the effects of tides and storm surges on coastal aquifers using a coupled surface-subsurface approach.

    PubMed

    Yang, Jie; Graf, Thomas; Herold, Maria; Ptak, Thomas

    2013-06-01

    Coastal aquifers are complex hydrologic systems because many physical processes interact: (i) variably saturated flow, (ii) spatial-temporal fluid density variations, (iii) tidal fluctuations, (iv) storm surges overtopping dykes, and (v) surface runoff of storm water. The HydroGeoSphere model is used to numerically simulate coastal flow dynamics, assuming a fully coupled surface-subsurface approach, accounting for all processes listed above. The diffusive wave approximation of the St. Venant equation is used to describe surface flow. Surface flow and salt transport are fully coupled with subsurficial variably saturated, variable-density flow and salt transport through mathematical terms that represent exchange of fluid mass and solute mass, respectively. Tides and storm surges induce a time-variant head that is applied to nodes of the surface domain. The approach is applied to real cases of tide and storm surge events. Tide simulation results confirm the existence of a recirculating zone, forming beneath the upper part of the intertidal zone. By monitoring the exchange fluid flux rates through the beach, it was found that the major inflow to the aquifer takes place at the upper part of the intertidal zone, which explains the formation of the recirculating zone. The recirculating zone is forming particularly during rising tide. Results from a storm surge simulation show that plume fingers develop below the flooded land surface. Natural remediation by seaward flowing freshwater is relatively slow, such that reducing the salt concentration in the aquifer down to drinking water standards takes up to 10 years. PMID:23603354

  16. Impact of sea level rise on tide gate function.

    PubMed

    Walsh, Sean; Miskewitz, Robert

    2013-01-01

    Sea level rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean sea level elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean sea level elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that sea level rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the sea level elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America. PMID:23379951

  17. Research-Based Teaching Unit on the Tides. Research Report

    ERIC Educational Resources Information Center

    Viiri, Jouni; Saari, Heikki

    2004-01-01

    The aim of this study was to develop a new research-based learning unit for tides to be used in lower secondary schools. The learning unit was based on the scientific theory of tides, textbooks, and also an analysis of students' conceptions. Descriptions are included of the content and the teaching-learning activities of the unit. The teacher talk…

  18. DEVELOPMENT AND EVALUATION OF A RUBBER "DUCK BILL" TIDE GATE

    EPA Science Inventory

    A unique 54 in. diameter "duckbill" rubber tide gate (RTG) was designed, fabricated, and installed in a typical New York City tide gate chamber. The operation of the RTG was observed over two years. The RTG was very effective in preventing the inflow of tidal waters and generally...

  19. Ocean tide models for satellite geodesy and Earth rotation

    NASA Technical Reports Server (NTRS)

    Dickman, Steven R.

    1991-01-01

    A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

  20. Orthogonal stack of global tide gauge sea level data

    NASA Technical Reports Server (NTRS)

    Trupin, A.; Wahr, J.

    1990-01-01

    Yearly and monthly tide gauge sea level data from around the globe are fitted to numerically generated equilibrium tidal data to search for the 18.6 year lunar tide and 14 month pole tide. Both tides are clearly evident in the results, and their amplitudes and phases are found to be consistent with a global equilibrium response. Global, monthly sea level data from outside the Baltic sea and Gulf of Bothnia are fitted to global atmospheric pressure data to study the response of the ocean to pressure fluctuations. The response is found to be inverted barometer at periods greater than two months. Global averages of tide gauge data, after correcting for the effects of post glacial rebound on individual station records, reveal an increase in sea level over the last 80 years of between 1.1 mm/yr and 1.9 mm/yr.

  1. Terminal weather information management

    NASA Technical Reports Server (NTRS)

    Lee, Alfred T.

    1990-01-01

    Since the mid-1960's, microburst/windshear events have caused at least 30 aircraft accidents and incidents and have killed more than 600 people in the United States alone. This study evaluated alternative means of alerting an airline crew to the presence of microburst/windshear events in the terminal area. Of particular interest was the relative effectiveness of conventional and data link ground-to-air transmissions of ground-based radar and low-level windshear sensing information on microburst/windshear avoidance. The Advanced Concepts Flight Simulator located at Ames Research Center was employed in a line oriented simulation of a scheduled round-trip airline flight from Salt Lake City to Denver Stapleton Airport. Actual weather en route and in the terminal area was simulated using recorded data. The microburst/windshear incident of July 11, 1988 was re-created for the Denver area operations. Six experienced airline crews currently flying scheduled routes were employed as test subjects for each of three groups: (1) A baseline group which received alerts via conventional air traffic control (ATC) tower transmissions; (2) An experimental group which received alerts/events displayed visually and aurally in the cockpit six miles (approx. 2 min.) from the microburst event; and (3) An additional experimental group received displayed alerts/events 23 linear miles (approx. 7 min.) from the microburst event. Analyses of crew communications and decision times showed a marked improvement in both situation awareness and decision-making with visually displayed ground-based radar information. Substantial reductions in the variability of decision times among crews in the visual display groups were also found. These findings suggest that crew performance will be enhanced and individual differences among crews due to differences in training and prior experience are significantly reduced by providing real-time, graphic display of terminal weather hazards.

  2. Weatherization and Intergovernmental Program - Weatherization Assistance Program

    SciTech Connect

    2010-06-01

    The U.S. Department of Energy’s (DOE) Weatherization Assistance Program reduces energy costs for low-income households by increasing the energy efficiency of their homes, while ensuring their health and safety.

  3. Beyond the Weather Chart: Weathering New Experiences.

    ERIC Educational Resources Information Center

    Huffman, Amy Bruno

    1996-01-01

    Describes an early childhood educator's approach to teaching children about rain, rainbows, clouds, precipitation, the sun, air, and wind. Recommends ways to organize study topics and describes experiments that can help children better understand the different elements of weather. (MOK)

  4. [Suicide and weather].

    PubMed

    Breuer, H W; Fischbach-Breuer, B R; Breuer, J; Goeckenjan, G; Curtius, J M

    1984-11-01

    In 151 patients, admitted to an intensive care unit after attempted suicide, the possible influence of weather at the time of the attempt was analysed retrospectively. The "biosynoptic daily analysis" of the German Weather Service provided the weather data. There was a 5% and 1%, respectively, significant level for the positive correlation between the time of the attempted suicide and the weather parameters "stable upslide, labile upslide, fog and thunderstorm" and the summarized parameters "warm air, upslide and weather drier than on the two preceding days". Significantly fewer attempts than expected occurred when the weather description was "low pressure and trough situation, labile ground layer--upslide above" and the summarized parameters "subsidence or downslide motion". Besides the individual factors such as the reaction to conflicts and the spectrum of reactions, exogenous factors like weather must be considered as important for the time of suicidal attempt. PMID:6499669

  5. A stochastic daily weather generator for skewed data

    NASA Astrophysics Data System (ADS)

    Flecher, C.; Naveau, P.; Allard, D.; Brisson, N.

    2010-07-01

    To simulate multivariate daily time series (minimum and maximum temperatures, global radiation, wind speed, and precipitation intensity), we propose a weather state approach with a multivariate closed skew-normal generator, WACS-Gen, that is able to accurately reproduce the statistical properties of these five variables. Our weather generator construction takes advantage of two elements. We first extend the classical wet and dry days dichotomy used in most past weather generators to the definition of multiple weather states using clustering techniques. The transitions among weather states are modeled by a first-order Markov chain. Second, the vector of our five daily variables of interest is sampled, conditionally on these weather states, from a closed skew-normal distribution. This class of distribution allows us to handle nonsymmetric behaviors. Our method is applied to the 20 years of daily weather measurements from Colmar, France. This example illustrates the advantages of our approach, especially improving the simulation of radiation and wind distributions.

  6. TIGA Tide Gauge Data Reprocessing at GFZ

    NASA Astrophysics Data System (ADS)

    Deng, Zhiguo; Schöne, Tilo; Gendt, Gerd

    2014-05-01

    To analyse the tide gauge measurements for the purpose of global long-term sea level change research a well-defined absolute reference frame is required by oceanographic community. To create such frame the data from a global GNSS network located at or near tide gauges are processed. For analyzing the GNSS data on a preferably continuous basis the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring Working Group (TIGA-WG) is responsible. As one of the TIGA Analysis Centers the German Research Centre for Geosciences (GFZ) is contributing to the IGS TIGA Reprocessing Campaign. The solutions of the TIGA Reprocessing Campaign will also contribute to 2nd IGS Data Reprocessing Campaign with GFZ IGS reprocessing solution. After the first IGS reprocessing finished in 2010 some improvements were implemented into the latest GFZ software version EPOS.P8: reference frame IGb08 based on ITRF2008, antenna calibration igs08.atx, geopotential model (EGM2008), higher-order ionospheric effects, new a priori meteorological model (GPT2), VMF mapping function, and other minor improvements. GPS data of the globally distributed tracking network of 794 stations for the time span from 1994 until end of 2012 are used for the TIGA reprocessing. To handle such large network a new processing strategy is developed and described in detail. In the TIGA reprocessing the GPS@TIGA data are processed in precise point positioning (PPP) mode to clean data using the IGS reprocessing orbit and clock products. To validate the quality of the PPP coordinate results the rates of 80 GPS@TIGA station vertical movement are estimated from the PPP results using Maximum Likelihood Estimation (MLE) method. The rates are compared with the solution of University of LaRochelle Consortium (ULR) (named ULR5). 56 of the 80 stations have a difference of the vertical velocities below 1 mm/yr. The error bars of PPP rates are significant larger than those of ULR5, which indicates large time correlated noise in

  7. Observations of the diurnal tide from space

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.; Wu, D. L.; Burrage, M. D.; Gell, D. A.; Grassl, H. J.; Lieberman, R. S.; Marshall, A. R.; Morton, Y. T.; Ortland, D. A.; Skinner, W. R.

    1994-01-01

    This study presents a climatology of mesospheric and lower-thermospheric diurnal tidal winds obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS). The observations reveal that although tidal structures are present at all times, like the prevailing zonal winds, they exhibit significant semiannual as well as other shorter-term variations in amplitude. Results are presented for a period extending over more than one year from November 1991 to July 1993. The 1,1 diurnal tidal amplitude of the meridional component, characterized by the value at an altitude of 90 km and a latitude of 22 deg, ranges from a minimum at solstice of less than 20 m per sec to an equinox maximum of over 70 m per sec. The vertical wavelength and phase of the tide show only slight variations throughout the year, with a suggestion of semiannual variations in both.

  8. Preliminary analysis of the connection between ocean dynamics and the noise of gravity tide observed at the Sopronbánfalva Geodynamical Observatory, Hungary

    NASA Astrophysics Data System (ADS)

    Papp, G.; Szűcs, E.; Battha, L.

    2012-10-01

    An experimental development of a computer controlled photoelectric ocular system applied for the LaCoste and Romberg G949 gravimeter made the continuous observation of time variation of gravity possible. The system was operated for half a year in the Sopronbánfalva Geodynamical Observatory to test its capabilities. The primary aim of this development was to provide an alternative and self-manageable solution instead of the standard electronic (Capacitive Position Indicator) reading of this type of gravimeter and use it for the monitoring of Earth tide. It, however, turned out that this system is sensitive enough to observe the effect of variable seismic noise (microseisms) due to the changes of ocean weather in the North Atlantic and North Sea regions at microGal level (1 μGal = 10-8 m/s2). Up to now not much attention was paid to its influence on the quality and accuracy of gravity observations because of the large distance (>1000 km) between the observation place (generally the Carpathian-Pannonian basin) and the locations (centres of storm zones of the northern hydrosphere) of triggering events. Based on an elementary harmonic surface deformation model the noise level of gravity observations was compared to the spectral characteristics of seismic time series recorded at the same time in the observatory. Although the sampling rate of gravity records was 120 s the daily variation of gravity noise level showed significant correlation with the variation of spectral amplitude distribution of the analysed high pass filtered (cut-off frequency = 0.005 Hz) seismograms up to 10 Hz. Also available daily maps of ocean weather parameters were used to support both the correlation analysis and the parameterization of the triggering events of microseisms for further statistical investigations. These maps, which were processed by standard image processing algorithms, provide numerical data about geometrical (distance and azimuth of the storm centres relative to the

  9. Preliminary analysis of the connection between ocean dynamics and the noise of gravity tide observed at the Sopronbánfalva Geodynamical Observatory, Hungary

    NASA Astrophysics Data System (ADS)

    Papp, G.; Szżcs, E.; Battha, L.

    2012-04-01

    An experimental development of a PC controlled CCD ocular system applied for the LaCoste and Romberg G949 gravimeter of the Geodetic and Geophysical Research Institute of the Hung. Acad. Sci. made the continuous observation of time variation of gravity possible. The system was operated for half a year in the Sopronbánfalva Geodynamical Observatory to test its capabilities. The primary aim of this development was to provide an alternative and self-manageable solution for the standard/factory CPI reading of this type of gravimeter and use it for the monitoring of earth tide phenomenon. It, however, turned out that this system is sensitive enough to observe the effect of variable seismic noise (microseisms) due to the changes of ocean weather in the North Atlantic and North Sea regions at microGal level (1 μGal=10-8 m/s2). Up to now much attention was not paid to its influence on the quality and accuracy of gravity observations because of the large distance (> 1000 km) between the observation place (generally the Carpathian-Pannonian basin) and the source locations (centers of storm zones of the northern hydrosphere). Based on an elementary single wave surface deformation model the noise levels of gravity observations were compared to the spectral characteristics of seismic time series recorded at the same time in the Observatory. Although the sampling rate of gravity records was 120 s the daily variation of gravity noise level could be correlated to the variation of spectral amplitude distribution of the analyzed high pass filtered (cut-off frequency = 0.005 Hz) seismograms in the frequency band between 0.005 Hz and 10 Hz. Also available daily maps of ocean weather parameters were used to support both the correlation analysis and the parametrization of the source of microseisms for further statistical investigations. These maps which were processed by standard image processing algorithms provide numerical data about geometrical (distance and azimuth of the source

  10. Space Weathering of Rocks

    NASA Technical Reports Server (NTRS)

    Noble, Sarah

    2011-01-01

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

  11. Panic anxiety, under the weather?

    NASA Astrophysics Data System (ADS)

    Bulbena, A.; Pailhez, G.; Aceña, R.; Cunillera, J.; Rius, A.; Garcia-Ribera, C.; Gutiérrez, J.; Rojo, C.

    2005-03-01

    The relationship between weather conditions and psychiatric disorders has been a continuous subject of speculation due to contradictory findings. This study attempts to further clarify this relationship by focussing on specific conditions such as panic attacks and non-panic anxiety in relation to specific meteorological variables. All psychiatric emergencies attended at a general hospital in Barcelona (Spain) during 2002 with anxiety as main complaint were classified as panic or non-panic anxiety according to strict independent and retrospective criteria. Both groups were assessed and compared with meteorological data (wind speed and direction, daily rainfall, temperature, humidity and solar radiation). Seasons and weekend days were also included as independent variables. Non-parametric statistics were used throughout since most variables do not follow a normal distribution. Logistic regression models were applied to predict days with and without the clinical condition. Episodes of panic were three times more common with the poniente wind (hot wind), twice less often with rainfall, and one and a half times more common in autumn than in other seasons. These three trends (hot wind, rainfall and autumn) were accumulative for panic episodes in a logistic regression formula. Significant reduction of episodes on weekends was found only for non-panic episodes. Panic attacks, unlike other anxiety episodes, in a psychiatric emergency department in Barcelona seem to show significant meteorotropism. Assessing specific disorders instead of overall emergencies or other variables of a more general quality could shed new light on the relationship between weather conditions and behaviour.

  12. Gastrointestinal Emergency Room Admissions and Florida Red Tide Blooms

    PubMed Central

    Kirkpatrick, Barbara; Bean, Judy A; Fleming, Lora E; Kirkpatrick, Gary; Grief, Lynne; Nierenberg, Kate; Reich, Andrew; Watkins, Sharon; Naar, Jerome

    2009-01-01

    Human exposure to brevetoxins during Florida red tide blooms formed by Karenia brevis has been documented to cause acute gastrointestinal, neurologic, and respiratory health effects.. Traditionally, the routes of brevetoxin exposure have been through the consumption of contaminated bivalve shellfish and the inhalation of contaminated aerosols. However, recent studies using more sensitive methods have demonstrated the presence of brevetoxins in many components of the aquatic food web which may indicate potential alternative routes for human exposure. This study examined whether the presence of a Florida red tide bloom affected the rates of admission for a gastrointestinal diagnosis to a hospital emergency room in Sarasota, FL. The rates of gastrointestinal diagnoses admissions were compared for a 3-month time period in 2001 when Florida red tide bloom was present onshore to the same 3-month period in 2002 when no Florida red tide bloom occurred. A significant 40% increase in the total number of gastrointestinal emergency room admissions for the Florida red tide bloom period was found compared to the non red tide period. These results suggest that the healthcare community may experience a significant and unrecognized impact from patients needing emergency medical care for gastrointestinal illnesses during Florida red tide blooms. Thus, additional studies characterizing the potential sources of exposure to the toxins, as well as the dose/effect relationship of brevetoxin exposure, should be undertaken. PMID:20161425

  13. Spectroscopic analysis of global tide gauge sea level data

    NASA Technical Reports Server (NTRS)

    Trupin, A.; Wahr, J.

    1990-01-01

    Yearly and monthly global tide-gage sea-level data are fitted to numerically generated tidal data in order to search for the 18.6-yr lunar nodal tide and 14-month pole tide. Both of these tides are clearly evident, with amplitudes and phases that are consistent with a global equilibrium response. The ocean's response to atmospheric pressure is studied with the least-squares fit technique. Consideration is given to the global rise in sea level, the effects of postglacial rebound, and the possible causes of the enhanced pole tides in the North Sea, the Baltic Sea, and the Gulf of Bothnia. The results support O'Connor's (1986) suggestion that the enhanced pole tide in these regions is due to meteorological forcing rather than a basin-scale resonance. Also, the global average of the tide-gage data show an increase in sea level over tha last 80 yr of between 1.1 and 1.9 mm/yr.

  14. Gastrointestinal Emergency Room Admissions and Florida Red Tide Blooms.

    PubMed

    Kirkpatrick, Barbara; Bean, Judy A; Fleming, Lora E; Kirkpatrick, Gary; Grief, Lynne; Nierenberg, Kate; Reich, Andrew; Watkins, Sharon; Naar, Jerome

    2010-01-01

    Human exposure to brevetoxins during Florida red tide blooms formed by Karenia brevis has been documented to cause acute gastrointestinal, neurologic, and respiratory health effects.. Traditionally, the routes of brevetoxin exposure have been through the consumption of contaminated bivalve shellfish and the inhalation of contaminated aerosols. However, recent studies using more sensitive methods have demonstrated the presence of brevetoxins in many components of the aquatic food web which may indicate potential alternative routes for human exposure.This study examined whether the presence of a Florida red tide bloom affected the rates of admission for a gastrointestinal diagnosis to a hospital emergency room in Sarasota, FL. The rates of gastrointestinal diagnoses admissions were compared for a 3-month time period in 2001 when Florida red tide bloom was present onshore to the same 3-month period in 2002 when no Florida red tide bloom occurred. A significant 40% increase in the total number of gastrointestinal emergency room admissions for the Florida red tide bloom period was found compared to the non red tide period.These results suggest that the healthcare community may experience a significant and unrecognized impact from patients needing emergency medical care for gastrointestinal illnesses during Florida red tide blooms. Thus, additional studies characterizing the potential sources of exposure to the toxins, as well as the dose/effect relationship of brevetoxin exposure, should be undertaken. PMID:20161425

  15. Spectral characteristics analysis of red tide water in mesocosm experiment

    NASA Astrophysics Data System (ADS)

    Cui, Tingwei; Zhang, Jie; Zhang, Hongliang; Ma, Yi; Gao, Xuemin

    2003-05-01

    Mesocosm ecosystem experiment with seawater enclosed of the red tide was carried out from July to September 2001. We got four species of biology whose quantities of bion are dominant in the red tide. During the whole process from the beginning to their dying out for every specie, in situ spectral measurements were carried out. After data processing, characteristic spectra of red tide of different dominant species are got. Via comparison and analysis of characteristics of different spectra, we find that in the band region between 685 and 735 nanometers, spectral characteristics of red tide is apparently different from that of normal water. Compared to spectra of normal water, spectra of red tide have a strong reflectance peak in the above band region. As to spectra of red tide dominated by different species, the situations of reflectance peaks are also different: the second peak of Mesodinium rubrum spectrum lies between 726~732 nm, which is more than 21nm away from the other dominant species spectra"s Leptocylindrus danicus"s second spectral peak covers 686~694nm; that of Skeletonema costatum lies between 691~693 nm. Chattonella marina"s second spectral peak lies about 703~705 nm. Thus we can try to determine whether red tide has occurred according to its spectral data. In order to monitor the event of red tide and identify the dominant species by the application of the technology of hyperspectral remote sensing, acquiring spectral data of different dominant species of red tide as much as possible becomes a basic work to be achieved for spectral matching, information extraction and so on based on hyperspectral data.

  16. NASA Connect: 'Plane Weather'

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Excerpt from the NASA Connect show 'Plane Weather' This clip explains what high and low pressure weather systems are, and how these affect weather patterns. Weather affects our daily lives. The elements of weather: rain, wind, fog, ice and snow affect the operation and flight of an airplane. In this program, NASA and FAA researchers will introduce students to math, science, and weather; demonstrate how these elements influence flight; and show how NASA and FAA research is used to limit the effects of these elements on flight. Students will examine: the tools, techniques, and technologies used by engineers and scientists to detect these and other climatological factors affecting aircraft in flight. The lesson and classroom experiment will involve students in the scientific process and emphasizing problem solving, measurement, and reasoning skills.

  17. RBSP Space Weather data

    NASA Astrophysics Data System (ADS)

    Weiss, M.; Fox, N. J.; Mauk, B. H.; Barnes, R. J.; Potter, M.; Romeo, G.; Smith, D.

    2012-12-01

    On August 23, 2012, NASA will launch two identical probes into the radiation belts to provide unprecedented insight into the physical processes and dynamics of near-Earth space. The RBSP mission in addition to the scientific data return, provides a 1Kbps real-time space weather broadcast data in support of real time space weather modeling, forecast and prediction efforts. Networks of ground stations have been identified to downlink the space weather data. The RBSP instrument suites have selected space weather data to be broadcast from their collected space data on board the spacecraft, a subset from measurements based on information normally available to the instrument. The data subset includes particle fluxes at a variety of energies, and magnetic and electric field data. This selected space weather data is broadcast at all times through the primary spacecraft science downlink antennas when an observatory is not in a primary mission-related ground contact. The collected data will resolve important scientific issues and help researchers develop and improve various models for the radiation belts that can be used by forecasters to predict space weather phenomena and alert astronauts and spacecraft operators to potential hazards. The near real-time data from RBSP will be available to monitor and analyze current environmental conditions, forecast natural environmental changes and support anomaly resolution. The space weather data will be available on the RBSP Science Gateway at http://athena.jhuapl.edu/ and will provide access to the space weather data received from the RBSP real-time space weather broadcast. The near real-time data will be calibrated and displayed on the web as soon as possible. The CCMC will ingest the RBSP space weather data into real-time models. The raw space weather data will be permanently archived at APL. This presentation will provide a first look at RBSP space weather data products.

  18. Weather and climate

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Recommendations for using space observations of weather and climate to aid in solving earth based problems are given. Special attention was given to: (1) extending useful forecasting capability of space systems, (2) reducing social, economic, and human losses caused by weather, (3) development of space system capability to manage and control air pollutant concentrations, and (4) establish mechanisms for the national examination of deliberate and inadvertent means for modifying weather and climate.

  19. The Effects of Thermal Tides and Dust on Traveling Waves in the Martian Atmosphere

    NASA Astrophysics Data System (ADS)

    Wang, H.; Toigo, A. D.; Richardson, M. I.

    2014-12-01

    Observations show that traveling waves with zonal wavenumber k = 3 correlate closely with the development of frontal / flushing dust storms which are important in the Martian dust cycle. Previous modeling work suggests that both the polar hood [Barnes et al., 2014] and the cap edge dust storms [Wang et al., 2013] have the potential to enhance these waves. In this presentation, we investigate the case of cap edge dust further, focusing on the following results. We will show that the relative strength of the traveling waves depends not only on the time, geolocation, height and variable under consideration, but also on the analysis method. For near surface temperature which is observable by spacecraft, the spectral and time averaged wave power can lead to a different answer than the monochromatic wave power. In particular, in the presence of cap edge dust, the modeled zonal wavenumber k = 3 can dominate the traveling wave spectra at times. In the presence of cap edge dust in the model, the enhancement of the k = 3 traveling waves is accompanied by pronounced increase of the diurnal tide. To test the effect of thermal tides on traveling waves, we have performed sensitivity runs where the insolation is replaced by the diurnally averaged value. We find that the amplitude of the k = 3 traveling waves are greatly reduced without thermal tides. Detailed analyses of the relationship between the waves will be presented.

  20. Bifurcation analysis of brown tide by reaction-diffusion equation using finite element method

    SciTech Connect

    Kawahara, Mutsuto; Ding, Yan

    1997-03-01

    In this paper, we analyze the bifurcation of a biodynamics system in a two-dimensional domain by virtue of reaction-diffusion equations. The discretization method in space is the finite element method. The computational algorithm for an eigenspectrum is described in detail. On the basis of an analysis of eigenspectra according to Helmholtz`s equation, the discrete spectra in regards to the physical variables are numerically obtained in two-dimensional space. In order to investigate this mathematical model in regards to its practical use, we analyzed the stability of two cases, i.e., hydranth regeneration in the marine hydroid Tubularia and a brown tide in a harbor in Japan. By evaluating the stability according to the linearized stability definition, the critical parameters for outbreaks of brown tide can be theoretically determined. In addition, results for the linear combination of eigenspectrum coincide with the distribution of the observed brown tide. Its periodic characteristic was also verified. 10 refs., 8 figs., 5 tabs.

  1. Tropical storm tracks in a global tide and storm surge reanalysis

    NASA Astrophysics Data System (ADS)

    Verlaan, Martin; Winsemius, Hessel; Vatvani, Deepak; Muis, Sanne; Ward, Philip

    2016-04-01

    Flooding due to tides and storm surges causes massive societal impacts and the largest economic damage of all flood hazards. To adequately estimate and counteract upon their risk, sound global scientific information on hazards due to storm surges and tides is required. Recently, a first global tide and storm surge reanalysis (GTSR) has been prepared (Muis et al., 2015) that provides a 36 year time series of sea levels, along with extreme value statistics. The GTSR is established using a physically based model, forced by meteorological reanalysis data. Validation of GTSR showed that tropical storms are underrepresented, firstly, due to the fact that they occur rarely and then only affect a limited area, and secondly, because the spatio-temporal resolution of reanalysis wind and pressure fields is too low to accurately represent the strong spatio-temporal variability of tropical storms. In this contribution, we show the GTSR as well as its recent advancements by contributing a large amount of historical tropical storm tracks into the analysis. This advancement is seen as a first step to accommodate tropical storms in the reanalysis. We estimate how the statistics of the meteorological extremes in pressure and wind are changing, and consequently, how this translates into new statistics of storm surge extremes.

  2. Between tide and wave marks: a unifying model of physical zonation on littoral shores

    PubMed Central

    Bird, Christopher E.; Franklin, Erik C.; Smith, Celia M.

    2013-01-01

    The effects of tides on littoral marine habitats are so ubiquitous that shorelines are commonly described as ‘intertidal’, whereas waves are considered a secondary factor that simply modifies the intertidal habitat. However mean significant wave height exceeds tidal range at many locations worldwide. Here we construct a simple sinusoidal model of coastal water level based on both tidal range and wave height. From the patterns of emergence and submergence predicted by the model, we derive four vertical shoreline benchmarks which bracket up to three novel, spatially distinct, and physically defined zones. The (1) emergent tidal zone is characterized by tidally driven emergence in air; the (2) wave zone is characterized by constant (not periodic) wave wash; and the (3) submergent tidal zone is characterized by tidally driven submergence. The decoupling of tidally driven emergence and submergence made possible by wave action is a critical prediction of the model. On wave-dominated shores (wave height ≫ tidal range), all three zones are predicted to exist separately, but on tide-dominated shores (tidal range ≫ wave height) the wave zone is absent and the emergent and submergent tidal zones overlap substantially, forming the traditional “intertidal zone”. We conclude by incorporating time and space in the model to illustrate variability in the physical conditions and zonation on littoral shores. The wave:tide physical zonation model is a unifying framework that can facilitate our understanding of physical conditions on littoral shores whether tropical or temperate, marine or lentic. PMID:24109544

  3. Determining optimum climate drivers for weather risk projections

    NASA Astrophysics Data System (ADS)

    Chavez, Erik; Kilian, Markus; Lucarini, Valerio

    2016-04-01

    In spite of the exponential increase of available data, the uncertainties of projections of weather variability, especially at local scale, have not decreased. This poses important challenges for the design of weather risk management strategies in various vulnerable sectors such as energy or agricultural production. This paper focuses on a two step methodology to enable projection of local weather risk in future climate scenarios. First, we focus on the optimum selection of drivers of regional weather patterns in order to project local weather variability risk estimates in future climate scenarios. This is carried out through the use of stochastic downscaling enabling conditional modelling of pixel-level distributions of weather variables as a function of inter-annual and inter-decadal climate variability drivers. Secondly, a statistical and physically-based climate model selection methodology is developed in order to produce a sub-ensemble of inter-annual and decadal variability drivers dataset that allows accurate and robust projection of weather variability. The case study of South Eastern Africa will be used. Datasets retrieved from CMIP5 repository in three RCP scenarios (historical, 8.5 and 2.5) are used as well as observed historical weather data.

  4. Global Earth Response to Loading by Ocean Tide Models

    NASA Technical Reports Server (NTRS)

    Estes, R. H.; Strayer, J. M.

    1979-01-01

    Mathematical and programming techniques to numerically calculate Earth response to global semidiurnal and diurnal ocean tide models were developed. Global vertical crustal deformations were evaluated for M sub 2, S sub 2, N sub 2, K sub 2, K sub 1, O sub 1, and P sub 1 ocean tide loading, while horizontal deformations were evaluated for the M sub 2 tidal load. Tidal gravity calculations were performed for M sub 2 tidal loads, and strain tensor elements were evaluated for M sub 2 loads. The M sub 2 solution used for the ocean tide included the effects of self-gravitation and crustal loading.

  5. The shaping of continental slopes by internal tides

    USGS Publications Warehouse

    Cacchione, D.A.; Pratson, Lincoln F.; Ogston, A.S.

    2002-01-01

    The angles of energy propagation of semidiurnal internal tides may determine the average gradient of continental slopes in ocean basins (???2 to 4 degrees). Intensification of near-bottom water velocities and bottom shear stresses caused by reflection of semi-diurnal internal tides affects sedimentation patterns and bottom gradients, as indicated by recent studies of continental slopes off northern California and New Jersey. Estimates of bottom shear velocities caused by semi-diurnal internal tides are high enough to inhibit deposition of fine-grained sediment onto the slopes.

  6. Angular momentum budget of the radiational S1 ocean tide

    NASA Astrophysics Data System (ADS)

    Schindelegger, Michael; Dobslaw, Henryk; Poropat, Lea; Salstein, David; Böhm, Johannes

    2016-04-01

    The balance of diurnal S1 oceanic angular momentum (OAM) variations through torques at the sea surface and the bottom topography is validated using both a barotropic and a baroclinic numerical tide model. This analysis discloses the extent to which atmosphere-driven S1 forward simulations are reliable for use in studies of high-frequency polar motion and changes in length-of-day. Viscous and dissipative torques associated with wind stress, bottom friction, as well as internal tidal energy conversion are shown to be small, and they are overshadowed by gravitational and pressure-related interaction forces. In particular, the zonal OAM variability of S1 is almost completely balanced by the water pressure torque on the local bathymetry, whereas in the prograde equatorial case also the air pressure torque on the seafloor as well as ellipsoidal contributions from the non-spherical atmosphere and solid Earth must be taken into account. Overall, the OAM budget is well closed in both the axial and the equatorial directions, thus allowing for an identification of the main diurnal angular momentum sinks in the ocean. The physical interaction forces are found to be largest at shelf breaks and continental slopes in low latitudes, with the most dominant contribution coming from the Indonesian archipelago.

  7. Cockpit weather information needs

    NASA Technical Reports Server (NTRS)

    Scanlon, Charles H.

    1992-01-01

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

  8. Weather assessment and forecasting

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Data management program activities centered around the analyses of selected far-term Office of Applications (OA) objectives, with the intent of determining if significant data-related problems would be encountered and if so what alternative solutions would be possible. Three far-term (1985 and beyond) OA objectives selected for analyses as having potential significant data problems were large-scale weather forecasting, local weather and severe storms forecasting, and global marine weather forecasting. An overview of general weather forecasting activities and their implications upon the ground based data system is provided. Selected topics were specifically oriented to the use of satellites.

  9. Pilot Weather Advisor System

    NASA Technical Reports Server (NTRS)

    Lindamood, Glenn; Martzaklis, Konstantinos Gus; Hoffler, Keith; Hill, Damon; Mehrotra, Sudhir C.; White, E. Richard; Fisher, Bruce D.; Crabill, Norman L.; Tucholski, Allen D.

    2006-01-01

    The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly real-time weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt of information would relieve the pilot of the time-consuming and distracting task of obtaining weather information via voice communication with ground stations. Second, the presentation of the information would be centered around a map format, thereby making the spatial and temporal relationships in the surrounding weather situation much easier to understand

  10. Weather it's Climate Change?

    NASA Astrophysics Data System (ADS)

    Bostrom, A.; Lashof, D.

    2004-12-01

    For almost two decades both national polls and in-depth studies of global warming perceptions have shown that people commonly conflate weather and global climate change. Not only are current weather events such as anecdotal heat waves, droughts or cold spells treated as evidence for or against global warming, but weather changes such as warmer weather and increased storm intensity and frequency are the consequences most likely to come to mind. Distinguishing weather from climate remains a challenge for many. This weather 'framing' of global warming may inhibit behavioral and policy change in several ways. Weather is understood as natural, on an immense scale that makes controlling it difficult to conceive. Further, these attributes contribute to perceptions that global warming, like weather, is uncontrollable. This talk presents an analysis of data from public opinion polls, focus groups, and cognitive studies regarding people's mental models of and 'frames' for global warming and climate change, and the role weather plays in these. This research suggests that priming people with a model of global warming as being caused by a "thickening blanket of carbon dioxide" that "traps heat" in the atmosphere solves some of these communications problems and makes it more likely that people will support policies to address global warming.

  11. Validating satellite altimeter measurements of internal tides with long-term TAO/TRITON buoy observations at 2°S-156°E

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao-Hui; Wang, Dong-Ping; Chen, Dake

    2015-05-01

    Satellite altimetry is regularly used to map the global distribution of mode-1 internal tides. Validating altimeter measurements of internal tides with in situ data is difficult as the mooring observations typically are too short compared with the altimetry. Here taking advantage of the long-term (since 1999) Tropical Atmosphere-Ocean/Triangle Trans-Ocean Buoy Network (TAO/TRITON) buoy observations at 2°S-156°E located at a TOPEX/Poseidon crossover in a region of strong internal tides, direct comparisons are made between altimeter and in situ measurements over a common 15 year period. The hourly buoy data are decimated every 9.9 day to emulate altimeter measurements. The altimeter and decimated buoy data are highly coherent at the aliased semidiurnal period (~60 day), and they agree well for the stationary semidiurnal internal tide. For the nonstationary internal tide, which consists of a significant annual cycle, the demodulated amplitude from the altimeter appears to be contaminated by nontidal signals. The demodulated amplitude from the decimated buoy data, on the other hand, is capable of resolving the temporal variability. This suggests the potential of mapping nonstationary internal tides from satellites.

  12. Global ionospheric weather

    SciTech Connect

    Decker, D.T.; Doherty, P.H.

    1994-02-28

    In the last year, the authors have studied several issues that are critical for understanding ionospheric weather. Work on global F-region modeling has consisted of testing the Phillips Laboratory Global Theoretical Ionosphere Model. Comparisons with both data and other theoretical models have been successfully conducted and are ongoing. GPS observations, as well as data analysis, are also ongoing. Data have been collected for a study on the limitations in making absolute ionospheric measurements using GPS. Another study on ionospheric variability is the first of its kind using GPS data. The observed seasonal total electron content behavior is consistent with that determined from the Faraday rotation technique. Work on the FAA's Phase 1 Wide Area Differential GPS (WADGPS) Satellite Navigation Testbed Experiment also continues. Initial results indicate that stations using operational WADGPS should be located no greater than 430 km apart. Work comparing the authors electron-proton-H atom model to both observations and other models has been generally successful. They have successfully modeled the creation of high-latitude large-scale plasma structures using two separate mechanisms (time-varying global convection and meso-scale convection events).

  13. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    NASA Astrophysics Data System (ADS)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-05-01

    -way coupling. Four levels of nested grids are used, from a 1 arc-min spherical coordinate grid in the deep ocean down to a 39-m Cartesian grid in the HRE. Bottom friction coefficients in the finer grids are calibrated for the tide to achieve the local spatially averaged MHW level at high tide in the HRE. Combined tsunami-tide simulations are then performed for four phases of the tide corresponding to each tsunami arriving at Sandy Hook (NJ): 1.5 h ahead, concurrent with, 1.5 h after, and 3 h after the local high tide. These simulations are forced along the offshore boundary of the third-level grid by linearly superposing time series of surface elevation and horizontal currents of the calibrated tide and each tsunami wave train; this is done in deep enough water for a linear superposition to be accurate. Combined tsunami-tide simulations are then performed with FUNWAVE-TVD in this and the finest nested grids. Results show that, for the 3 PMTs, depending on the tide phase, the dynamic simulations lead to no or to a slightly increased inundation in the HRE (by up to 0.15 m depending on location), and to larger currents than for the simulations over a static level; the CRT SMF proxy tsunami is the PMT leading to maximum inundation in the HRE. For all tide phases, nonlinear interactions between tide and tsunami currents modify the elevation, current, and celerity of tsunami wave trains, mostly in the shallower water areas of the HRE where bottom friction dominates, as compared to a linear superposition of wave elevations and currents. We note that, while dynamic simulations predict a slight increase in inundation, this increase may be on the same order as, or even less than sources of uncertainty in the modeling of tsunami sources, such as their initial water elevation, and in bottom friction and bathymetry used in tsunami grids. Nevertheless, results in this paper provide insight into the magnitude and spatial variability of tsunami propagation and impact in the complex inland

  14. The Sea Surface Temperature Variation during the Spring Tide and Neap Tide in the South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Shih-Jen; Kuo, Nan-Jung; Ho, Chung-Ru; Lo, Yao-Tsai

    2016-04-01

    The sea surface temperature (SST) data of MODIS/Terra (Moderate-resolution Imaging Spectroradiometer) are used to analyze the SST difference between the spring tide and the neap tide in the South China Sea (SCS) from 2001 to 2013. The 4 stations from north to south in the SCS are used to investigate the variation of SST. The results show the lowest SST found on January and the highest SST found on June. The standard deviation of SST in shallow regions (St. 1 and St. 4) are larger than the deep regions (St. 2 and St. 3). During the winter and spring the standard deviation of SST at the neap tide are greater than the spring tide period. From the later winter to early summer, the SST during the neap tide period is greater than the spring tide period. They are more obvious in the shallow regions. Meanwhile the influence of tide action in the shallow regions is greater than it in the deep regions.

  15. The lunar semidiurnal air pressure tide in in-situ data and ECMWF reanalyses

    NASA Astrophysics Data System (ADS)

    Schindelegger, Michael; Dobslaw, Henryk

    2016-04-01

    A gridded empirical model of the lunar semidiurnal air pressure tide L2 is deduced through multiquadric interpolation of more than 2000 globally distributed tidal estimates from land barometers and moored buoys. The resulting climatology serves as an independent standard to validate the barometric L2 oscillations that are present in ECMWF's (European Centre for Medium-Range Weather Forecasts) global atmospheric reanalyses despite the omission of gravitational forcing mechanisms in the involved forecast routines. Inconsistencies between numerical and empirical L2 solutions are found to be small even though the reanalysis models typically underestimate equatorial peak pressures by 10-20% and produce slightly deficient tidal phases in latitudes south of 30°N. Through using a time-invariant reference surface over both land and water and assimilating marine pressure data without accounting for vertical sensor movements due to the M2 ocean tide, ECMWF-based tidal solutions are also prone to strong local artifacts. Additionally, the dependency of the lunar tidal oscillation in atmospheric analysis systems on the meteorological input data is demonstrated based on a recent ECMWF twentieth-century reanalysis (ERA-20C) which draws its all of its observational constraints from in-situ registrations of pressure and surface winds. The L2 signature prior to 1950 is particularly indicative of distinct observing system changes, such as the paucity of marine data during both World Wars or the opening of the Panama Canal in 1914 and the associated adjustment of commercial shipping routes.

  16. Seasonal variations in Pluto's atmospheric tides

    NASA Astrophysics Data System (ADS)

    French, Richard G.; Toigo, Anthony D.; Gierasch, Peter J.; Hansen, Candice J.; Young, Leslie A.; Sicardy, Bruno; Dias-Oliveira, Alex; Guzewich, Scott D.

    2015-01-01

    Pluto's tenuous atmosphere exhibits remarkable seasonal change as a result of the planet's substantial obliquity and highly eccentric orbit. Over the past two decades, occultations have revealed that the atmospheric pressure on Pluto has increased substantially, perhaps by a factor as large as 2 to 4, as the planet has moved from equinox towards solstice conditions. These data have also shown variations in the strength of the dynamical activity in the atmosphere, as revealed by the varying abundance and amplitude of spikes in the occultation light curves resulting from refractive focussing by atmospheric waves. Toigo et al. (Toigo et al. [2010]. Icarus, 208, 402-411) explored the possibility that these waves are caused by solar-induced sublimation and diurnal deposition from N2 frost patches, driven by weak vertical winds resulting from the rising and sinking gas as it is released from or deposited onto the surface. Here, we extend this model to account explicitly for seasonal variations in average insolation and for the significant damping of vertical wave propagation by kinematic viscosity and thermal diffusivity (Hubbard et al. [2009]. Icarus, 204, 284-289). Damping is extremely effective in suppressing vertical propagation of waves with vertical wavelengths of a few kilometers or less, and the dominant surviving tidal modes have characteristic vertical wavelengths λ ∼ 10-13 km . We estimate the expected strength and regional characteristics of atmospheric tides over the course of Pluto's orbit for a variety of assumed spatial distributions of surface frost and atmospheric surface pressure. We compute the predicted strength of tide-induced wave activity based on the actual frost distribution observed on Pluto from Hubble Space Telescope (HST) observations (Stern et al. [1997]. Astron. J., 113, 827; Buie et al. [2010]. Astron. J., 139, 1128-1143), and compare the results to calculations for volatile transport models of Young (Young [2013]. Astrophys. J., 766

  17. Weather and emotional state

    NASA Astrophysics Data System (ADS)

    Spasova, Z.

    2010-09-01

    Introduction Given the proven effects of weather on the human organism, an attempt to examine its effects on a psychic and emotional level has been made. Emotions affect the bio-tonus, working ability and concentration, hence their significance in various domains of economic life, such as health care, education, transportation, tourism, etc. Data and methods The research has been made in Sofia City within a period of 8 months, using 5 psychological methods (Eysenck Personality Questionnaire (EPQ), State-Trait Anxiety Inventory (STAI), Test for Self-assessment of the emotional state (developed by Wessman and Ricks), Test for evaluation of moods and Test "Self-confidence - Activity - Mood" (developed by the specialists from the Military Academy in Saint Petersburg). The Fiodorov-Chubukov's complex-climatic method was used to characterize meteorological conditions because of the purpose to include in the analysis a maximal number of meteorological elements. 16 weather types are defined in dependence of the meteorological elements values according to this method. Abrupt weather changes from one day to another, defined by the same method, were considered as well. Results and discussions The results obtained by t-test show that the different categories of weather lead to changes in the emotional status, which indicates a character either positive or negative for the organism. The abrupt weather changes, according to expectations, have negative effect on human emotions but only when a transition to the cloudy weather or weather type, classified as "unfavourable" has been realized. The relationship between weather and human emotions is rather complicated since it depends on individual characteristics of people. One of these individual psychological characteristics, marked by the dimension "neuroticism", has a strong effect on emotional reactions in different weather conditions. Emotionally stable individuals are more "protected" to the weather influence on their emotions

  18. Explaining the road accident risk: weather effects.

    PubMed

    Bergel-Hayat, Ruth; Debbarh, Mohammed; Antoniou, Constantinos; Yannis, George

    2013-11-01

    This research aims to highlight the link between weather conditions and road accident risk at an aggregate level and on a monthly basis, in order to improve road safety monitoring at a national level. It is based on some case studies carried out in Work Package 7 on "Data analysis and synthesis" of the EU-FP6 project "SafetyNet-Building the European Road Safety Observatory", which illustrate the use of weather variables for analysing changes in the number of road injury accidents. Time series analysis models with explanatory variables that measure the weather quantitatively were used and applied to aggregate datasets of injury accidents for France, the Netherlands and the Athens region, over periods of more than 20 years. The main results reveal significant correlations on a monthly basis between weather variables and the aggregate number of injury accidents, but the magnitude and even the sign of these correlations vary according to the type of road (motorways, rural roads or urban roads). Moreover, in the case of the interurban network in France, it appears that the rainfall effect is mainly direct on motorways--exposure being unchanged, and partly indirect on main roads--as a result of changes in exposure. Additional results obtained on a daily basis for the Athens region indicate that capturing the within-the-month variability of the weather variables and including it in a monthly model highlights the effects of extreme weather. Such findings are consistent with previous results obtained for France using a similar approach, with the exception of the negative correlation between precipitation and the number of injury accidents found for the Athens region, which is further investigated. The outlook for the approach and its added value are discussed in the conclusion. PMID:23928504

  19. Overview of Aerosolized Florida Red Tide Toxins: Exposures and Effects

    PubMed Central

    Fleming, Lora E.; Backer, Lorraine C.; Baden, Daniel G.

    2005-01-01

    Florida red tide is caused by Karenia brevis, a dinoflagellate that periodically blooms, releasing its potent neurotoxin, brevetoxin, into the surrounding waters and air along the coast of the Gulf of Mexico. Exposure to Florida red tide toxins has been associated with adverse human health effects and massive fish and marine mammal deaths. The articles in this mini-monograph describe the ongoing interdisciplinary and interagency research program that characterizes the exposures and health effects of aerosolized Florida red tide toxins (brevetoxins). The interdisciplinary research program uses animal models and laboratory studies to develop hypotheses and apply these findings to in situ human exposures. Our ultimate goal is to develop appropriate prevention measures and medical interventions to mitigate or prevent adverse health effects from exposure to complex mixtures of aerosolized red tide toxins. PMID:15866773

  20. Numerical Study for Baroclinic Tides Modified By an Oblique Current

    NASA Astrophysics Data System (ADS)

    Wang, C. A.; Jan, S.

    2014-12-01

    Previous investigations suggest that when the internal waves throughout a northwest - southeast background flow, its amplitudes, propagation path, phase speed might be changed. The process occurring when internal tides meet a background geostrophic current at an angle rather than perpendicular to the current in a zonal channel is investigated using a numerical model with simplified forcing, topography and hydrographic setting. We compared numerical results of two different background conditions: (1) no background flow and (2) oblique background flow. Results indicate that the westward baroclinic energy flux tends to increase when internal tides pass through the background geostrophic flow. Different oblique angles of the background flow also cause different responses on the propagation of internal tides. The energy exchange between the internal tides and background flow is analyzed using an energy balance equation as well as the numerical results.

  1. Energy Dissipation by Tides and Librations in Synchronous Satellites

    NASA Technical Reports Server (NTRS)

    Bills, B. G.; Ray, R. D.

    2000-01-01

    Energy dissipation associated with physical librations of large synchronous satellites may be important for maintaining internal fluid layers. Depending on the depth and viscosity of the fluid layer, viscous heating from librations may exceeed that from tides.

  2. Catching the Tide: A Review of Tidal Energy Systems

    ERIC Educational Resources Information Center

    Harris, Frank

    2014-01-01

    Harnessing energy from the tides is a much-promoted but rarely realised way of generating electricity. This article examines some of the systems that are currently in use or under development, and outlines their economic, environmental and technical implications.

  3. 5. Detail of west side of pier, at low tide. ...

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

    5. Detail of west side of pier, at low tide. - Charlestown Navy Yard, Pier 10, Between Piers 9 & 11 along Mystic River on Charlestown Waterfront at eastern edge of Charlestown Navy Yard, Boston, Suffolk County, MA

  4. 2. Pilings at end of Pier 11, low tide, view ...

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

    2. Pilings at end of Pier 11, low tide, view to north. - Charlestown Navy Yard, Pier 11, Charlestown Waterfront at confluence of Little Mystic Channel & Mystic River at northernmost ent of Navy Yard, Boston, Suffolk County, MA

  5. Teacher's Weather Sourcebook.

    ERIC Educational Resources Information Center

    Konvicka, Tom

    This book is a teaching resource for the study of weather-related phenomena. A "weather unit" is often incorporated into school study because of its importance to our daily lives and because of its potential to cut across disciplinary content. This book consists of two parts. Part I covers the major topics of atmospheric science such as the modern…

  6. KSC Weather and Research

    NASA Technical Reports Server (NTRS)

    Maier, Launa; Huddleston, Lisa; Smith, Kristin

    2016-01-01

    This briefing outlines the history of Kennedy Space Center (KSC) Weather organization, past research sponsored or performed, current organization, responsibilities, and activities, the evolution of weather support, future technologies, and an update on the status of the buoys located offshore of Cape Canaveral Air Force Station and KSC.

  7. Weather Fundamentals: Clouds. [Videotape].

    ERIC Educational Resources Information Center

    1998

    The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) discusses how clouds form, the different types of clouds, and the important role they play in…

  8. Mild and Wild Weather.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Presents background information and six activities that focus on clouds, precipitation, and stormy weather. Each activity includes an objective, recommended age level(s), subject area(s), and instructional strategies. Also provided are two ready-to-copy pages (a coloring page on lightning and a list of weather riddles to solve). (JN)

  9. People and Weather.

    ERIC Educational Resources Information Center

    NatureScope, 1985

    1985-01-01

    Provides: (1) background information on ways weather influences human lives; (2) activities related to this topic; and (3) a ready-to-copy page with weather trivia. Each activity includes an objective, list of materials needed, recommended age level(s), subject area(s), and instructional strategies. (JN)

  10. World weather program

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A brief description of the Global Weather Experiment is presented. The world weather watch program plan is described and includes a global observing system, a global data processing system, a global telecommunication system, and a voluntary cooperation program. A summary of Federal Agency plans and programs to meet the challenges of international meteorology for the two year period, FY 1980-1981, is presented.

  11. Exercising in Cold Weather

    MedlinePlus

    ... www.nia.nih.gov/Go4Life Exercising in Cold Weather Exercise has benefits all year, even during winter. ... activities when it’s cold outside: l Check the weather forecast. If it’s very windy or cold, exercise ...

  12. Weather and Culture.

    ERIC Educational Resources Information Center

    Contemporary Learning Center, Houston, TX.

    This document is a minicourse on the interaction of weather, environment, and culture. It is designed for the high school student to read and self-administer. Performance objectives, enabling activities, and postassessment questions are given for each of eight modules. The modules are: (1) Basic Facts About Your Weather Known As Rain, (2) The…

  13. Home Weatherization Visit

    ScienceCinema

    Chu, Steven

    2013-05-29

    Secretary Steven Chu visits a home that is in the process of being weatherized in Columbus, OH, along with Ohio Governor Ted Strickland and Columbus Mayor Michael Coleman. They discuss the benefits of weatherization and how funding from the recovery act is having a direct impact in communities across America.

  14. Weathering Database Technology

    ERIC Educational Resources Information Center

    Snyder, Robert

    2005-01-01

    Collecting weather data is a traditional part of a meteorology unit at the middle level. However, making connections between the data and weather conditions can be a challenge. One way to make these connections clearer is to enter the data into a database. This allows students to quickly compare different fields of data and recognize which…

  15. On Observing the Weather

    ERIC Educational Resources Information Center

    Crane, Peter

    2004-01-01

    Rain, sun, snow, sleet, wind... the weather affects everyone in some way every day, and observing weather is a terrific activity to attune children to the natural world. It is also a great way for children to practice skills in gathering and recording information and to learn how to use simple tools in a standardized fashion. What better way to…

  16. Fabulous Weather Day

    ERIC Educational Resources Information Center

    Marshall, Candice; Mogil, H. Michael

    2007-01-01

    Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in…

  17. The Home Weather Station.

    ERIC Educational Resources Information Center

    Steinke, Steven D.

    1991-01-01

    Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)

  18. Weatherizing a Structure.

    ERIC Educational Resources Information Center

    Metz, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with weatherizing a structure. Its objective is for the student to be able to analyze factors related to specific structures that indicate need for weatherizing activities and to determine steps to correct defects in structures that…

  19. Weather Fundamentals: Wind. [Videotape].

    ERIC Educational Resources Information Center

    1998

    The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) describes the roles of the sun, temperature, and air pressure in creating the incredible power…

  20. Aviation Weather Program (AWP)

    NASA Technical Reports Server (NTRS)

    Foote, Brant

    1993-01-01

    The Aviation Weather Program (AWP) combines additional weather observations, improved forecast technology, and more efficient distribution of information to pilots, controllers, and automated systems to improve the weather information provided to the air traffic control system, pilots, and other users of aviation weather information. Specific objectives include the needs to: improve airport and en-route capacity by accurate, high resolution, timely forecasts of changing weather conditions affecting airport and en-route operations; improve analyses and forecasts of upper-level winds for efficient flight planning and traffic management; and increase flight safety through improved aviation weather hazard forecasting (e.g. icing, turbulence, severe storms, microbursts, or strong winds). The AWP would benefit from participation in a cooperative multiscale experiment by obtaining data for: evaluation of aviation weather forecast products, analysis of four dimensional data assimilation schemes, and experimental techniques for retrieving aerosol and other visibility parameters. A multiscale experiment would also be helpful to AWP by making it possible to evaluate the added benefit of enhanced data sets collected during the experiment on those forecast and analysis products. The goals of the Coperative Multiscale Experiment (CME) are an essential step in attaining the long-term AWP objective of providing two-to-four hour location-specific forecasts of significant weather. Although the possibility of a funding role for the AWP in the CME is presently unclear, modest involvement of Federal Aviation Administration (FAA)/AWP personnel could be expected.

  1. Designing a Weather Station

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    The collection and analysis of weather data is crucial to the location of alternate energy systems like solar and wind. This article presents a design challenge that gives students a chance to design a weather station to collect data in advance of a large wind turbine installation. Data analysis is a crucial part of any science or engineering…

  2. Tide- and wind-driven flushing of Boston Harbor, Massachusetts

    USGS Publications Warehouse

    Signell, Richard

    1992-01-01

    The flushing of Boston Harbor, a shallow, tidally dominated embayment with little fresh water input, is investigated using a depth-averaged model. The modeled tidal currents exhibit strong spatial variability and ebb/flood asymmetry due to complex topography and coastline geometry and were verified by shipboard acoustic Doppler current profiler measurements. At the inlets to the harbor, the asymmetry between flood and ebb gives rise to a net exchange of water, which acts over successive tidal cycles to flush the harbor. The flushing is examined by tracking water that starts out in Boston Harbor for 40 M2 tidal cycles. The tidal flushing is very efficient at mixing water in the vicinity of the inlets over several tidal cycles, but efficiency decreases with time as ``tidal mixing regions'' form on either side of the harbor inlets. When wind forcing is included, the wind-driven currents act to flush the tidal mixing regions, giving rise to more efficient flushing. The exception is when the wind is from the southwest, which confines the jet-like ebb flow from the harbor and therefore reduces the flushing efficiency. In general, flushing is shown to be a two-step process: (1) rapid exchange due to tides over a large region in the vicinity of the harbor inlets and (2) flushing of this region by wind-driven flow. The model also demonstrates that flushing is not uniform over the entire harbor but occurs rapidly in the deep tidal channels and slowly in the regions of weak tidal currents around the harbor periphery. Although the depth-averaged approach to flushing is appropriate over most of the harbor due to the harbor's shallow depth and broad depth distribution, the lack of bathymetric variability and the presence of locally important density driven currents in the Boston Inner Harbor indicates that flushing of this localized area must be approached with a three-dimensional model.

  3. Weathering and weathering rates of natural stone

    SciTech Connect

    Winkler, E.M. )

    1987-01-01

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

  4. Solutions Network Formulation Report. Improving NOAA's Tides and Currents Through Enhanced Data Inputs from NASA's Ocean Surface Topography Mission

    NASA Technical Reports Server (NTRS)

    Guest, DeNeice C.

    2006-01-01

    The Nation uses water-level data for a variety of practical purposes, including hydrography, nautical charting, maritime navigation, coastal engineering, and tsunami and storm surge warnings (NOAA, 2002; Digby et al., 1999). Long-term applications include marine boundary determinations, tidal predictions, sea-level trend monitoring, oceanographic research, and climate research. Accurate and timely information concerning sea-level height, tide, and ocean current is needed to understand their impact on coastal management, disaster management, and public health. Satellite altimeter data products are currently used by hundreds of researchers and operational users to monitor ocean circulation and to improve scientists understanding of the role of the oceans in climate and weather. The NOAA (National Oceanic and Atmospheric Administration) National Ocean Service has been monitoring sea-level variations for many years (NOAA, 2006). NOAA s Tides & Currents DST (decision support tool, managed by the Center for Operational Oceanographic Products and Services, is the portal to a vast collection of oceanographic and meteorological data (historical and real-time), predictions, and nowcasts and forecasts. This report assesses the capacity of NASA s satellite altimeter data to meet societal decision support needs through incorporation into NOAA s Tides & Currents.

  5. TIDE Observations of Cusp and Cleft Multiple Ion Populations

    NASA Technical Reports Server (NTRS)

    Coffey, Victoria N.; Chandler, Michael O.; Moore, Thomas E.

    2000-01-01

    The southern pole pass of Polar/TIDe at 5000 km allows a study of the distributions of the cusp and cleft. We discuss observations of TIDE (Thermal Ion Dynamics Experiment) as it passes the southern pole on March 29, 1999. A mixture of several cold outflowing ions (0.3-10 eV) are measured simultaneously with magnetospheric precipitation (greater than 100 eV). We will show a study of these multiple plasma distributions, their source, and their interaction.

  6. Effects of Long Period Ocean Tides on the Earth's Rotation

    NASA Technical Reports Server (NTRS)

    Gross, Richard S.; Chao, Ben F.; Desai, Shailen D.

    1996-01-01

    The spectra of polar motion excitation functions exhibit enhanced power in the fortnightly tidal band. This enhanced power is attributed to ocean tidal excitation. Ocean tide models predict polar motion excitation effects that differ with each other, and with observations, by factors as large as 2-3. There is a need for inproved models for the effect of long-period ocean tides on Earth's rotation.

  7. Another look at North Sea pole tide dynamics

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.; Preisig, J. R.

    1986-01-01

    The mechanism proposed by Wunsch (1974) to explain pole tide observations in the North Sea is evaluated. Wunsch's equations governing pole tide in the North Sea are presented, and solutions for correcting the depth, stream function, and deviation of the tidal height from the equilibrium values are described. The similarity between the Stokes paradox and the tidal equations of the North Sea, and the need for inclusion of inertial terms in the tidal equations are discussed.

  8. Space weather applications with PICARD

    NASA Astrophysics Data System (ADS)

    Dudok de Wit, Thierry; Thuillier, Gerard

    The PICARD mission aims at providing a better understanding of the origin of solar variability and the relations between the Sun and Earth's climate. Some of the instruments from PICARD will also be of direct interest to space weather. SODISM will provide regular UV images at 215 and 393 nm wavelength and PREMOS will measure the solar spectral irradiance in 5 channels, 3 of which are in the visible and in the near-infrared. Some potential applications will be discussed as well as synergies with other spectral irradiance observations, such as by LYRA on PROBA2 and EVE on SDO.

  9. POPULATION SYNCHRONY WITHIN AND AMONG LEPIDOPTERA SPECIES IN RELATION TO WEATHER, PHYLOGENY, AND LARVEL PHENOLOGY

    EPA Science Inventory

    1. The population dynamics of native herbivore species in central Appalachian deciduous forests were studied by analysing patterns of synchrony among intra- and interspecific populations and weather. 2. Spatial synchrony of 10 Lepidoptera species and three weather variables (min...

  10. NASA Connect: 'Plane Weather'

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Excerpt from the NASA Connect show 'Plane Weather' This clip explains how our weather occurs, and why Solar radiation is responsible. Weather affects our daily lives. The elements of weather: rain, wind, fog, ice and snow affect the operation and flight of an airplane. In this program, NASA and FAA researchers will introduce students to math, science, and weather; demonstrate how these elements influence flight; and show how NASA and FAA research is used to limit the effects of these elements on flight. Students will examine: the tools, techniques, and technologies used by engineers and scientists to detect these and other climatological factors affecting aircraft in flight. The lesson and classroom experiment will involve students in the scientific process and emphasizing problem solving, measurement, and reasoning skills.

  11. NASA Connect: 'Plane Weather'

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Excerpt from the NASA Connect show 'Plane Weather' This clip explains what high and low pressure weather systems are, and how they form. Weather affects our daily lives. The elements of weather: rain, wind, fog, ice and snow affect the operation and flight of an airplane. In this program, NASA and FAA researchers will introduce students to math, science, and weather; demonstrate how these elements influence flight; and show how NASA and FAA research is used to limit the effects of these elements on flight. Students will examine: the tools, techniques, and technologies used by engineers and scientists to detect these and other climatological factors affecting aircraft in flight. The lesson and classroom experiment will involve students in the scientific process and emphasizing problem solving, measurement, and reasoning skills.

  12. Statistical Sampling of Tide Heights Study

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The goal of the study was to determine if it was possible to reduce the cost of verifying computational models of tidal waves and currents. Statistical techniques were used to determine the least number of samples required, in a given situation, to remain statistically significant, and thereby reduce overall project costs. Commercial, academic, and Federal agencies could benefit by applying these techniques, without the need to 'touch' every item in the population. For example, the requirement of this project was to measure the heights and times of high and low tides at 8,000 locations for verification of computational models of tidal waves and currents. The application of the statistical techniques began with observations to determine the correctness of submitted measurement data, followed by some assumptions based on the observations. Among the assumptions were that the data were representative of data-collection techniques used at the measurement locations, that time measurements could be ignored (that is, height measurements alone would suffice), and that the height measurements were from a statistically normal distribution. Sample means and standard deviations were determined for all locations. Interval limits were determined for confidence levels of 95, 98, and 99 percent. It was found that the numbers of measurement locations needed to attain these confidence levels were 55, 78, and 96, respectively.

  13. DYNAMICAL TIDES IN ROTATING PLANETS AND STARS

    SciTech Connect

    Goodman, J.; Lackner, C.

    2009-05-10

    Tidal dissipation may be important for the internal evolution as well as the orbits of short-period massive planets-hot Jupiters. We revisit a mechanism proposed by Ogilvie and Lin for tidal forcing of inertial waves, which are short-wavelength, low-frequency disturbances restored primarily by Coriolis rather than buoyancy forces. This mechanism is of particular interest for hot Jupiters, because it relies upon a rocky core, and because these bodies are otherwise largely convective. Compared to waves excited at the base of the stratified, externally heated atmosphere, waves excited at the core are more likely to deposit heat in the convective region and thereby affect the planetary radius. However, Ogilvie and Lin's results were numerical, and the manner of the wave excitation was not clear. Using WKB methods, we demonstrate the production of short waves by scattering of the equilibrium tide off the core at critical latitudes. The tidal dissipation rate associated with these waves scales as the fifth power of the core radius, and the implied tidal Q is of order ten million for nominal values of the planet's mass, radius, orbital period, and core size. We comment upon an alternative proposal by Wu for exciting inertial waves in an unstratified fluid body by means of compressibility rather than a core. We also find that even a core of rock is unlikely to be rigid. But Ogilvie and Lin's mechanism should still operate if the core is substantially denser than its immediate surroundings.

  14. Probing the tides in interacting galaxy pairs

    NASA Technical Reports Server (NTRS)

    Borne, Kirk D.

    1990-01-01

    Detailed spectroscopic and imaging observations of colliding elliptical galaxies revealed unmistakable diagnostic signatures of the tidal interactions. It is possible to compare both the distorted luminosity distributions and the disturbed internal rotation profiles with numerical simulations in order to model the strength of the tidal gravitational field acting within a given pair of galaxies. Using the best-fit numerical model, one can then measure directly the mass of a specific interacting binary system. This technique applies to individual pairs and therefore complements the classical methods of measuring the masses of galaxy pairs in well-defined statistical samples. The 'personalized' modeling of galaxy pairs also permits the derivation of each binary's orbit, spatial orientation, and interaction timescale. Similarly, one can probe the tides in less-detailed observations of disturbed galaxies in order to estimate some of the physical parameters for larger samples of interacting galaxy pairs. These parameters are useful inputs to the more universal problems of (1) the galaxy merger rate, (2) the strength and duration of the driving forces behind tidally stimulated phenomena (e.g., starbursts and maybe quasi steller objects), and (3) the identification of long-lived signatures of interaction/merger events.

  15. The black tide model of QSOs

    NASA Technical Reports Server (NTRS)

    Young, P. J.; Shields, G. A.; Wheeler, J. C.

    1977-01-01

    The paper develops certain aspects of a model wherein a QSO is a massive black hole located in a dense galactic nucleus, with its growth and luminosity fueled by tidal disruption of passing stars. Cross sections for tidal disruptions are calculated, taking into account the thermal energy of stars, relativistic effects, and partial disruption removing only the outer layers of a star. Accretion rates are computed for a realistic distribution of stellar masses and evolutionary phases, the effect of the black hole on the cluster distribution is examined, and the red-giant disruption rate is evaluated for hole mass of at least 300 million solar masses, the cutoff of disruption of main-sequence stars. The results show that this black-tide model can explain QSO luminosities of at least 1 trillion suns if the black hole remains almost maximally Kerr as it grows above 100 million solar masses and if 'loss-cone' depletion of the number of stars in disruptive orbits is unimportant.

  16. Reconstruction of regional mean sea level anomalies from tide gauges using the neural network approach

    NASA Astrophysics Data System (ADS)

    Wenzel, M.; Schroeter, J.

    2009-04-01

    BPN several alternatives are tested. This includes a reconstruction using an EOF basis estimated from all timesteps that have a complete tide gauge dataset. Furthermore a "forecast" network is build, that is trained to compute the values at all tide gauge positions for timestep (n+1) from all values at the steps (n) and (n-1). Additionally an equivalent "backcast" network is constructed that computes the values for step (n-1) from the steps (n) and (n+1). The resulting SLA's are presented. The results appear to be relatively insensitive against what is filled into the data gaps as far as the amount of missing input data does not exceed 20%, i.e. after 1950. Nearly all regions show a sea level rise with a multidecadal/interannual variability superimposed.

  17. Monitoring Sea Level by Tide Gauges and GPS at Barcelona and Estartit Harbours

    NASA Astrophysics Data System (ADS)

    Martinez Benjamin, J. J.; Gili, J.; Lopez, R.; Tapia, A.; Bosch, E.; Perez, B.; Pros, F.

    2012-04-01

    Sea level is an environmental variable which is widely recognised as being important in many scientific disciplines as a control parameter for coastal dynamical processes or climate processes in the coupled atmosphere-ocean systems, as well as engineering applications. A major source of sea-level data are the national networks of coastal tide gauges, in Spain belonging to different institutions as the Instituto Geográfico Nacional (IGN), Puertos del Estado (PE), Instituto Hidrográfico de la Marina (IHM), etc. The tide gauge of l'Estartit is a traditional floating gauge placed 21 years ago and has an accuracy of ± 2 mm. Since 1996, l'Estartit tide gauge has been co-located with geodetic techniques (GPS measurements of XU, Utilitary Network, and XdA, Levelling Network,) and it is tied to the SPGIC (Integrated Geodetic Positioning System of Catalonia) project of the Cartographic Institute of Catalunya (ICC). In 2006, due to the work for the expansion of the harbour, the tide gauge had to be moved. Before the work started, appropiate GPS measurements were carried out in order to ensure the connection of the tide gauge data. During October 2006 and May 2008, the tide gauge was inactive and it has been moved on to a new location inside the harbour. In June 2008, new GPS and levelling measures have been done in order to tie the new location into SPGIC project and to co-locate old data respect the new one. Although l'Estartit does not have a GPS permanent station, it is possible to build a virtual one from the service "CATNET web" of the ICC. "CATNET web" is a data distribution system of a virtual GPS permanent station via web. From the coordinates where you want to place the virtual station, the time interval and the measurement rate, the system generates a RINEX file under the requested conditions. At Barcelona harbour there is one MIROS radar tide gauge belonging to Puertos del Estado (Spanish Harbours). It is placed at the dock 140 of the ENAGAS Building.The radar

  18. Sunspots, Space Weather and Climate

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

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

  19. Health Issues and Space Weather

    NASA Astrophysics Data System (ADS)

    Crosby, N.

    2009-04-01

    The possibility that solar activity and variations in the Earth's magnetic field may affect human health has been debated for many decades but is still a "scientific topic" in its infancy. By learning whether and, if so, how much the Earth's space weather can influence the daily health of people will be of practical importance. Knowing whether human genetics, include regulating factors that take into account fluctuations of the Earth's magnetic field and solar disturbances, indeed exist will also benefit future interplanetary space travelers. Because the atmospheres on other planets are different from ours, as well as their interaction with the space environment, one may ask whether we are equipped with the genetics necessary to take this variability into account. The goal of this presentation is to define what is meant by space weather as a health risk and identify the long-term socio-economic effects on society that such health risks would have. Identifying the physical links between space weather sources and different effects on human health, as well as the parameters (direct and indirect) to be monitored, the potential for such a cross-disciplinary study will be invaluable, for scientists and medical doctors, as well as for engineers.

  20. Lunar and Solar Torques on the Oceanic Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Bills, Bruce G.; Chao, Benjamin Fong

    1998-01-01

    A general framework for calculating lunar and solar torques on the oceanic tides is developed in terms of harmonic constituents. Axial torques and their associated angular momentum and earth-rotation variations are deduced from recent satellite-altimeter and satellite-tracking tide solutions. Torques on the prograde components of the tide produce the familiar secular braking of the rotation rate. The estimated secular acceleration is approximately -1300 sec/century(sup 2) (less 4% after including atmospheric tides); the implied rate of change in the length of day is 2.28 milliseconds/century. Torques on the retrograde components of the tide produce periodic rotation variations at twice the tidal frequency. Interaction torques, e.g. solar torques on lunar tides, generate a large suite of rotation-rate variations at sums and differences of the original tidal frequencies. These are estimated for periods from 18.6 years to quarter-diurnal. At subdaily periods the angular momentum variations are 5 to 6 orders of magnitude smaller than the variations caused by ocean tidal currents.

  1. Geodynamic Effects of Ocean Tides: Progress and Problems

    NASA Technical Reports Server (NTRS)

    Richard, Ray

    1999-01-01

    Satellite altimetry, particularly Topex/Poseidon, has markedly improved our knowledge of global tides, thereby allowing significant progress on some longstanding problems in geodynamics. This paper reviews some of that progress. Emphasis is given to global-scale problems, particularly those falling within the mandate of the new IERS Special Bureau for Tides: angular momentum, gravitational field, geocenter motion. For this discussion I use primarily the new ocean tide solutions GOT99.2, CSR4.0, and TPXO.4 (for which G. Egbert has computed inverse-theoretic error estimates), and I concentrate on new results in angular momentum and gravity and their solid-earth implications. One example is a new estimate of the effective tidal Q at the M_2 frequency, based on combining these ocean models with tidal estimates from satellite laser ranging. Three especially intractable problems are also addressed: (1) determining long-period tides in the Arctic [large unknown effect on the inertia tensor, particularly for Mf]; (2) determining the global psi_l tide [large unknown effect on interpretations of gravimetry for the near-diurnal free wobble]; and (3) determining radiational tides [large unknown temporal variations at important frequencies]. Problems (2) and (3) are related.

  2. Dynamic ocean-tide effects on Earth's rotation

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1993-01-01

    This article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.

  3. Differences between mean tide level and mean sea level

    NASA Astrophysics Data System (ADS)

    Woodworth, P. L.

    2016-07-01

    This paper discusses the differences between mean tide level (MTL) and mean sea level (MSL) as demonstrated using information from a global tide gauge data set. The roles of the two main contributors to differences between MTL and MSL (the M4 harmonic of the M2 semidiurnal tide, and the combination of the diurnal tides K1 and O1) are described, with a particular focus on the spatial scales of variation in MTL-MSL due to each contributor. Findings from the tide gauge data set are contrasted with those from a state-of-the-art global tide model. The study is of interest within tidal science, but also has practical importance regarding the type of mean level used to define land survey datums. In addition, an appreciation of MTL-MSL difference is important in the use of the historical sea level data used in climate change research, with implications for some of the data stored in international databanks. Particular studies are made of how MTL and MSL might differ through the year, and if MTL is measured in daylight hours only, as has been the practice of some national geodetic agencies on occasions in the past.

  4. Fortnightly Earth Rotation, Ocean Tides, and Mantle Anelasticity

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, Gary D.

    2011-01-01

    Sustained accurate measurements of earth rotation are one of the prime goals of Global Geodetic Observing System (GGOS). We here concentrate on the fortnightly (Mf) tidal component of earth-rotation data to obtain new results concerning anelasticity of the mantle at this period. The study comprises three parts: (1) a new determination of the Mf component of polar motion and length-of-day from a multi-decade time series of space-geodetic data; (2) the use of the polar-motion determination as one constraint in the development of a hydrodynamic ocean model of the Mf tide; and (3) the use of these results to place new constraints on mantle anelasticity. Our model of the Mf ocean tide assimilates more than fourteen years of altimeter data from the Topex/Poseidon and Jason-1 satellites. The polar motion data, plus tide-gauge data and independent altimeter data, give useful additional information, with only the polar motion putting constraints on tidal current velocities. The resulting ocean-tide model, plus the dominant elastic body tide, leaves a small residual in observed length-of-day caused by mantle anelasticity. The inferred effective tidal 0 of the anelastic body tide is 90 and is in line with a omega-alpha frequency dependence with alpha in the range 0.2--0.3.

  5. Fortnightly Ocean Tides, Earth Rotation, and Mantle Anelasticity

    NASA Technical Reports Server (NTRS)

    Ray, Richard; Egbert, Gary

    2012-01-01

    The fortnightly Mf ocean tide is the largest of the long-period tides (periods between 1 week and 18.6 years), but Mf is still very small, generally 2 cm or less. All long-period tides are thought to be near equilibrium with the astronomical tidal potential, with an almost pure zonal structure. However, several lines of evidence point to Mf having a significant dynamic response to forcing. We use a combination of numerical modeling, satellite altimetry, and observations of polar motion to determine the Mf ocean tide and to place constraints on certain global properties, such as angular momentum. Polar motion provides the only constraints on Mf tidal currents. With a model of the Mf ocean tide in hand, we use it to remove the effects of the ocean from estimates of fortnightly variations in length-of-day. The latter is dominated by the earth's body tide, but a small residual allows us to place new constraints on the anelasticity of the earth's mantle. The result gives the first experimental confirmation of theoretical predictions made by Wahr and Bergen in 1986.

  6. Dynamics of the North Sea pole tide reconsidered

    NASA Technical Reports Server (NTRS)

    Wunsch, Carl

    1986-01-01

    The anomalous tide in the North Sea, driven by the Chandler wobble, is here re-examined. A previously published solution in which these 'pole tide' observations were explained as a forced co-oscillation from the deep water tide is shown to be untenable, because it is very unlikely that the deep ocean tide is anything but equilibrium. Using the same physics as in the previous solution (viscous, linear, quasi-geostrophic dynamics), it is now suggested that the only plausible explanation is that there is a coincidental resonance between the long-wavelength branch topographic Rossby wave of the North Sea and the direct driving by the pole tide potential. This resonance is not a basin-resonance, but that of a free wave driven by a travelling forcing function. Simplified models reproduce the observations in qualitative fashion. If this explanation is the correct one, then the Arctic seas north of Asia and North America appear to be likely candidates as other regions where there may be a large pole tide response and, hence, a locus of wobble dissipation. Given the difficulties of observation, the long times required, and the general instability of the dissipation calculation with the simplified analytical model, probably a numerical model will be required for further progress.

  7. Tsunami hazard assessment in the Hudson River Estuary based on dynamic tsunami-tide simulations

    NASA Astrophysics Data System (ADS)

    Shelby, Michael; Grilli, Stéphan T.; Grilli, Annette R.

    2016-05-01

    -way coupling. Four levels of nested grids are used, from a 1 arc-min spherical coordinate grid in the deep ocean down to a 39-m Cartesian grid in the HRE. Bottom friction coefficients in the finer grids are calibrated for the tide to achieve the local spatially averaged MHW level at high tide in the HRE. Combined tsunami-tide simulations are then performed for four phases of the tide corresponding to each tsunami arriving at Sandy Hook (NJ): 1.5 h ahead, concurrent with, 1.5 h after, and 3 h after the local high tide. These simulations are forced along the offshore boundary of the third-level grid by linearly superposing time series of surface elevation and horizontal currents of the calibrated tide and each tsunami wave train; this is done in deep enough water for a linear superposition to be accurate. Combined tsunami-tide simulations are then performed with FUNWAVE-TVD in this and the finest nested grids. Results show that, for the 3 PMTs, depending on the tide phase, the dynamic simulations lead to no or to a slightly increased inundation in the HRE (by up to 0.15 m depending on location), and to larger currents than for the simulations over a static level; the CRT SMF proxy tsunami is the PMT leading to maximum inundation in the HRE. For all tide phases, nonlinear interactions between tide and tsunami currents modify the elevation, current, and celerity of tsunami wave trains, mostly in the shallower water areas of the HRE where bottom friction dominates, as compared to a linear superposition of wave elevations and currents. We note that, while dynamic simulations predict a slight increase in inundation, this increase may be on the same order as, or even less than sources of uncertainty in the modeling of tsunami sources, such as their initial water elevation, and in bottom friction and bathymetry used in tsunami grids. Nevertheless, results in this paper provide insight into the magnitude and spatial variability of tsunami propagation and impact in the complex inland

  8. Riser tensioning wave and tide compensating system for a floating platform

    SciTech Connect

    Heeres, C.J.; Larsen, C.H.

    1980-09-16

    A riser tensioner cylinder is provided with a hollow piston rod which forms a second cylinder in which a ram is reciprocated. The free end of the ram is connected to a link which in turn is connected to the end of the riser for providing tension on the riser. The ram reciprocates in the second cylinder under constant pressure to compensate for wave action on the floating platform and the second cylinder is automatically positioned within the first cylinder for adjustment for tide, vessel offset or other infrequent but variable factors.

  9. Rock strength reductions during incipient weathering

    NASA Astrophysics Data System (ADS)

    Kelly, P. J.; Anderson, S. P.; Blum, A.

    2012-12-01

    Patrick Kelly, Suzanne Anderson, Alex Blum In rock below the surface, temperature swings are damped, water flow is limited, and biota are few. Yet rock weathers, presumably driven by these environmental parameters. We use rock strength as an indicator of rock weathering in Gordon Gulch in the Boulder Creek Critical Zone Observatory, a watershed at 2500 m underlain by Proterozoic gneiss intruded by the Boulder Creek granodiorite. Fresh rock is found at depths of 8-30 m in this area, and the thickness of the weathered rock zone imaged with shallow seismic refraction is greater on N-facing slopes than S-facing slopes (Befus et al., 2011, Vadose Zone J.). We use the Brazilian splitting test to determine tensile strength of cores collected with a portable drilling rig. Spatial variations in rock strength that we measure in the top 2 m of the weathered rock mantle can be connected to two specific environmental variables: slope aspect and the presence of a soil mantle. We find weaker rock on N-facing slopes and under soil. There is no clear correlation between rock strength and the degree of chemical alteration in these minimally weathered rocks. Denudation rates of 20-30 microns/yr imply residence times of 105-106 years within the weathered rock layers of the critical zone. Given these timescales, rock weathering is more likely to have occurred under glacial climate conditions, when periglacial processes prevailed in this non-glaciated watershed. Incipient weathering of rock appears to be controlled by water and frost cracking in Gordon Gulch. Water is more effectively delivered to the subsurface on N-facing slopes, and is more likely held against rock surfaces under soil than on outcrops. These moisture conditions, and the lower surface temperatures that prevail on N-facing slopes also favor frost cracking as an important weathering process.

  10. Highlights of Space Weather Services/Capabilities at NASA/GSFC Space Weather Center

    NASA Technical Reports Server (NTRS)

    Fok, Mei-Ching; Zheng, Yihua; Hesse, Michael; Kuznetsova, Maria; Pulkkinen, Antti; Taktakishvili, Aleksandre; Mays, Leila; Chulaki, Anna; Lee, Hyesook

    2012-01-01

    The importance of space weather has been recognized world-wide. Our society depends increasingly on technological infrastructure, including the power grid as well as satellites used for communication and navigation. Such technologies, however, are vulnerable to space weather effects caused by the Sun's variability. NASA GSFC's Space Weather Center (SWC) (http://science.gsfc.nasa.gov//674/swx services/swx services.html) has developed space weather products/capabilities/services that not only respond to NASA's needs but also address broader interests by leveraging the latest scientific research results and state-of-the-art models hosted at the Community Coordinated Modeling Center (CCMC: http://ccmc.gsfc.nasa.gov). By combining forefront space weather science and models, employing an innovative and configurable dissemination system (iSWA.gsfc.nasa.gov), taking advantage of scientific expertise both in-house and from the broader community as well as fostering and actively participating in multilateral collaborations both nationally and internationally, NASA/GSFC space weather Center, as a sibling organization to CCMC, is poised to address NASA's space weather needs (and needs of various partners) and to help enhancing space weather forecasting capabilities collaboratively. With a large number of state-of-the-art physics-based models running in real-time covering the whole space weather domain, it offers predictive capabilities and a comprehensive view of space weather events throughout the solar system. In this paper, we will provide some highlights of our service products/capabilities. In particular, we will take the 23 January and the 27 January space weather events as examples to illustrate how we can use the iSWA system to track them in the interplanetary space and forecast their impacts.

  11. The actual measurements at the tide gauges do not support strongly accelerating twentieth-century sea-level rise reconstructions

    NASA Astrophysics Data System (ADS)

    Parker, A.

    2016-03-01

    Contrary to what is claimed by reconstructions of the Global Mean Sea Level (GMSL) indicating accelerating sea level rates of rise over the twentieth-century, the actual measurements at the tide gauges show the sea levels have not risen nor accelerated that much. The most recent estimation by Hay et al [1] of the twentieth-century global mean sea level (GMSL) rise is the last attempt to give exact reconstructions without having enough information of the state of the world oceans over a century where unfortunately the good measurements were not that many. The information on relative rates of rise at the tide gauges and land subsidence of global positioning system (GPS) domes suggest the relative rate of rise is about 0.25mm/year, without any detectable acceleration. [The naïve average of all the world tide gauges of sufficient quality and length of the Permanent Service to Mean Sea Level (PSMSL) data base], Both the relative rates of rise at the tide gauges and the land vertical velocity of GPS domes of the Système d'Observation du Niveau des Eaux Littorales (SONEL) data base are strongly variable in space and time to make a nonsense the GMSL estimation.

  12. The actual measurements at the tide gauges do not support strongly accelerating twentieth-century sea-level rise reconstructions

    NASA Astrophysics Data System (ADS)

    Parker, A.

    2016-03-01

    Contrary to what is claimed by reconstructions of the Global Mean Sea Level (GMSL) indicating accelerating sea level rates of rise over the twentieth-century, the actual measurements at the tide gauges show the sea levels have not risen nor accelerated that much. The most recent estimation by Hay et al of the twentieth-century global mean sea level (GMSL) rise is the last attempt to give exact reconstructions without having enough information of the state of the world oceans over a century where unfortunately the good measurements were not that many. The information on relative rates of rise at the tide gauges and land subsidence of global positioning system (GPS) domes suggest the relative rate of rise is about 0.25mm/year, without any detectable acceleration. [The naïve average of all the world tide gauges of sufficient quality and length of the Permanent Service to Mean Sea Level (PSMSL) data base], Both the relative rates of rise at the tide gauges and the land vertical velocity of GPS domes of the Système d'Observation du Niveau des Eaux Littorales (SONEL) data base are strongly variable in space and time to make a nonsense the GMSL estimation.

  13. The Space Weather Reanalysis

    NASA Astrophysics Data System (ADS)

    Kihn, E. A.; Ridley, A. J.; Zhizhin, M.

    2002-12-01

    The objective of this project is to generate a complete 11 year space weather representation using physically consistent data-driven space weather models. The project will create a consistent, integrated historical record of the near Earth space environment by coupling observational data from space environmental monitoring systems archived at NGDC with data-driven, physically based numerical models. The resulting product will be an enhanced look at the space environment on consistent grids, time resolution, coordinate systems and containing key fields allowing an interested user to quickly and easily incorporate the impact of the near-Earth space climate in environmentally sensitive models. Currently there are no easily accessible long term climate archives available for the space-weather environment. Just as with terrestrial weather it is crucial to understand both daily weather forecasts as well as long term climate changes, so this project will demonstrate the ability to generate a meaningful and physically derived space weather climatology. The results of this project strongly support the DOD's Environmental Scenario Generator (ESG) project. The ESG project provides tools for intellegent data mining, classification and event detection which could be applied to a historical space-weather database. The two projects together provide a suite of tools for the user interested in modeling the effect of the near-earth space environment. We will present results and methodologies developed during the first two years of effort in the project.

  14. Global ocean tides. Part V. The diurnal principal lunar tide (O1), atlas of tidal charts and maps. Final report

    SciTech Connect

    Schwiderski, E.W.

    1981-05-20

    In Part I of this report (AD-A060 913), a unique hydrodynamical interpolation technique was introduced, extensively tested, and evaluated in order to compute partial global ocean tides in great detail and with a high degree of accuracy. This novel method has been applied to construct the diurnal principal lunar (O1) ocean tide with a relative accuracy of better than 5 cm anywhere in the open oceans. The resulting tidal amplitudes and phases are tabulated on a 1 deg x 1 deg grid system in an atlas of 42 deg x 71 deg overlapping charts covering the whole oceanic globe. A corresponding atlas of global corange and cotidal maps is included to provide the reader with a quick general overview of the major tidal phenomena. The specifying hydrodynamical parameters of the model are listed along with quoted sources of empirical tide data, and significant tidal features are explained and discussed. The diurnal O1 ocean tide is found to resemble closely the diurnal K1 tide and qualitatively also the semidiurnal S2 and M2 tides which were presented in Parts IV, III, and II of this report, respectively (AD's A104 334, A104 333, and A084 694).

  15. Global ocean tides. Part VII. The diurnal principal solar tide (P1), atlas of tidal charts and maps. Final report

    SciTech Connect

    Schwiderski, E.W.

    1981-05-01

    In Part I (Schwiderski, 1978a) of this report, a unique hydrodynamical interpolation technique was introduced, extensively tested, and evaluated in order to compute partial global ocean tides in great detail and with a high degree of accuracy. This novel method has been applied to construct the diurnal principal solar (P1) ocean tide with a relative accuracy of better than 5 cm anywhere in the open oceans. The resulting tidal amplitudes and phases are tabulated on a 1 deg X 1 deg grid system in an atlas of 42 deg X 71 deg overlapping charts covering the whole oceanic globe. A corresponding atlas of global corange and cotidal maps is included to provide the reader with a quick general overview of the major tidal phenomena. The specifying hydrodynamical parameters of the model are listed along with quoted sources of empirical tide data, and significant tidal features are explained and discussed. As expected, since the periods of the diurnal tides P1 (24.07h) and K1 (23.93 h) differ by only 0.14 h, these two tides resemble very closely each other (compare Part IV). Significant differences occur only in regions of rapid tidal variations. Of course, P1 resembles also the diurnal 01 tide but to a visibly lesser degree (see Part V).

  16. Food Safety for Warmer Weather

    MedlinePlus

    ... Fight Off Food Poisoning Food Safety for Warmer Weather In warm-weather months, who doesn’t love to get outside ... to keep foods safe to eat during warmer weather. If you’re eating or preparing foods outside, ...

  17. Weather--An Integrated Unit

    ERIC Educational Resources Information Center

    McConnell, Vivian

    1976-01-01

    Outlined is a two week unit on weather offered as independent study for sixth- and seventh-year students in Vancouver, Canada, schools. Included is a section on weather lore and a chart of weather symbols. (SL)

  18. Hypothermia: A Cold Weather Hazard

    MedlinePlus

    ... Weather Hazard Heath and Aging Hypothermia: A Cold Weather Hazard What Are The Signs Of Hypothermia? Taking ... cold air. But, not everyone knows that cold weather can also lower the temperature inside your body. ...

  19. Environmental Education Tips: Weather Activities.

    ERIC Educational Resources Information Center

    Brainard, Audrey H.

    1989-01-01

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

  20. What caused the rise of water level in the battle of Luermen bay in 1661? Tsunami, Storm surge, or Tide?

    NASA Astrophysics Data System (ADS)

    Wu, Tso-Ren; Wu, Han; Tsai, Yu-Lin

    2016-04-01

    In 1661, Chinese navy led by General Zheng Chenggong at the end of Ming Dynasty had a naval battle against Netherlands. This battle was not only the first official sea warfare that China confronted the Western world, but also the only naval battle won by Chinese Navy so far. This event was important because it changed the fate of Taiwan until today. One of the critical points that General Zheng won the battle was entering Luermen bay unexpected. Luermen bay was and is an extreme shallow bay with a 2.1m maximum water depth during the high tide, which was not possible for a fleet of 20,000 marines to across. Therefore, no defense was deployed from the Netherlands side. However, plenty of historical literatures mentioned a strange phenomenon that helped Chinese warships entered the Luermen bay, the rise of water level. In this study, we will discuss the possible causes that might rise the water level, e.g. Tsunami, storm surge, and high tide. We analyzed it based on the knowledge of hydrodynamics. We performed the newly developed Impact Intensify Analysis (IIA) for finding the potential tsunami sources, and the COMCOT tsunami model was adopted for the nonlinear scenario simulations, associated with the high resolution bathymetry data. Both earthquake and mudslide tsunamis were inspected. Other than that, we also collected the information of tide and weather for identifying the effects form high tide and storm surge. After the thorough study, a scenario that satisfy most of the descriptions in the historical literatures will be presented. The results will explain the cause of mysterious event that changed the destiny of Taiwan.

  1. Sun, weather, and climate

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Goldberg, R. A.

    1985-01-01

    The general field of sun-weather/climate relationships, that is, apparent weather and climate responses to solar activity is introduced and theoretical and experimental suggestions for further research to identify and investigate the unknown causal mechanisms are provided. Topics of discussion include: (1) solar-related correlation factors and energy sources; (2) long-term climatic trends; (3) short-term meteorological correlations; (4) miscellaneous obscuring influences; (5) physical processes and mechanisms; (6) recapitulation of sun-weather relationships; and (7) guidelines for experiments.

  2. Tides stir up deep Arctic heat

    NASA Astrophysics Data System (ADS)

    Green, Mattias; Rippeth, Tom; Lincoln, Ben; Lenn, Yueng; Bacon, Sheldon; Sundfjord, Arild

    2015-04-01

    The Arctic is warming at twice the rate of the rest of the planet. One of the largest sources of heat to the Arctic Ocean is the warm salty Atlantic water (AW) which enters through the Fram Strait and circulates at intermediate depth round the Arctic basin. The heat contained in the AW is sufficient to entirely melt the Arctic sea ice but is insulated from the surface by a layer of colder fresher water. Across much of the Arctic Ocean there is insufficient turbulence to drive vertical mixing, and so heat fluxes are a result of double diffusion (DD) and are consequently weak (< 0.1 W m-2). Here we present a new pan-Arctic series of direct measurements of TKE dissipation rate. The new measurements show enhanced turbulent mixing, and hence heat fluxes, over much of the continental slope around the Arctic boundary. The rate of TKE dissipation is found to increase with the bathymetric slope and vary longitudinally with the largest values to the north of Svalbard resulting in enhanced diapycnal heat fluxes over this region (20 W m-2). The observed 2-order of magnitude longitudinal variation in TKE dissipation rate correlates with the rate of dissipation of tidal energy, estimated from the local difference between the work done by the tide generating force and the tidal energy flux divergence from the TPXO8 inverse tidal solution. This correlation leads to the conclusion that the enhanced mixing observed over the continental shelf break north of Svalbard is a result of tidal processes.

  3. Interpretation of earth tide response of three deep, confined aquifers

    SciTech Connect

    Narasimhan, T.N.; Kanehiro, B.Y.; Witherspoon, P.A.

    1984-03-10

    The response of a confined, areally infinite aquifer to external loads imposed by earth tides is examined. Because the gravitational influence of celestial objects occurs over large areas of the earth, the confined aquifer is assumed to respond in an undrained fashion. Since undrained response is controlled by water compressibility, earth tide response can be directly used only to evaluate porous medium compressibility if porosity is known. Moreover, since specific storage S/sub s/ quantifies a drained behavior of the porous medium, one cannot directly estimate S/sub s/from earth tide response. Except for the fact that barometric changes act both on the water surface in the well and on the aquifer as a whole while stress changes associated with earth tides act only in the aquifer, the two phenomena influence the confined aquifer in much the same way. In other words, barometric response contains only as much information on the elastic properties of the aquifer as the earth tide response does. Factors such as well bore storage, aquifer transmissivity, and storage coefficient contribute to time lag and damping of the aquifer response as observed in the well. Analysis shows that the observation of fluid pressure changes alone, without concurrent measurement of external stress changes, is sufficient to interpret uniquely earth tide response. In the present work, change in external stress is estimated from dilatation by assuming a reasonable value for bulk modulus. Earth tide response of geothermal aquifers from Marysville, Montana. East Mesa, California; and Raft River Valley, Idaho, were analyzed, and the ratio of S/sub 3/ to porosity was estimated. Comparison of these estimates with independent pumping tests show reasonable agreement.

  4. Tidal asymmetry in estuaries with mixed semidiurnal/diurnal tides

    NASA Astrophysics Data System (ADS)

    Nidzieko, Nicholas J.

    2010-08-01

    Tidal asymmetry in estuaries with mixed, mainly semidiurnal tides arises from both the interaction of principal tides and the higher harmonics generated by distortions within the estuary. The duration asymmetry in rise and fall of water level caused by principal tides on the west coast of the continental United States is ebb-dominant, and so the tide entering estuaries is also ebb-dominant, prior to any internal distortions within the estuary. The interaction of higher harmonics with principal constituents either augments or cancels the duration asymmetry in the principal tides. In estuaries where tidal elevation and velocity phase are near quadrature (90° out of phase), the duration asymmetry in tidal elevation leads to asymmetries in tidal current magnitude. Asymmetry can be conveniently quantified in terms of the sample skewness, γ1, the normalized third sample moment about the mean. An analytic approximation to the skewness shows that traditional metrics of asymmetry, namely the ratio of constituent amplitudes and the relative constituent phase difference, arise from calculating the third sample moment. Observations from three California estuaries of different morphologies are presented as an illustration of how skewness can be used to quantify asymmetry in real systems. As in semidiurnal systems, morphology is a good predictor of whether higher harmonics engender ebb-dominance or flood-dominance, however asymmetry imposed by principal tides at the mouth must first be overcome and so there is a spatial evolution in the total asymmetry. Quantifying observations via skewness should be considered in addition to traditional metrics in estuaries with mixed tides.

  5. Improved Estimates of Temporally Coherent Internal Tides and Energy Fluxes from Satellite Altimetry

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Chao, Benjamin F. (Technical Monitor)

    2002-01-01

    Satellite altimetry has opened a surprising new avenue to observing internal tides in the open ocean. The tidal surface signatures are very small, a few cm at most, but in many areas they are robust, owing to averaging over many years. By employing a simplified two dimensional wave fitting to the surface elevations in combination with climatological hydrography to define the relation between the surface height and the current and pressure at depth, we may obtain rough estimates of internal tide energy fluxes. Initial results near Hawaii with Topex/Poseidon (T/P) data show good agreement with detailed 3D (three dimensional) numerical models, but the altimeter picture is somewhat blurred owing to the widely spaced T/P tracks. The resolution may be enhanced somewhat by using data from the ERS-1 (ESA (European Space Agency) Remote Sensing) and ERS-2 satellite altimeters. The ERS satellite tracks are much more closely spaced (0.72 deg longitude vs. 2.83 deg for T/P), but the tidal estimates are less accurate than those for T/P. All altimeter estimates are also severely affected by noise in regions of high mesoscale variability, and we have obtained some success in reducing this contamination by employing a prior correction for mesoscale variability based on ten day detailed sea surface height maps developed by Le Traon and colleagues. These improvements allow us to more clearly define the internal tide surface field and the corresponding energy fluxes. Results from throughout the global ocean will be presented.

  6. A semiparametric multivariate and multisite weather generator

    NASA Astrophysics Data System (ADS)

    Apipattanavis, Somkiat; Podestá, Guillermo; Rajagopalan, Balaji; Katz, Richard W.

    2007-11-01

    We propose a semiparametric multivariate weather generator with greater ability to reproduce the historical statistics, especially the wet and dry spells. The proposed approach has two steps: (1) a Markov Chain for generating the precipitation state (i.e., no rain, rain, or heavy rain), and (2) a k-nearest neighbor (k-NN) bootstrap resampler for generating the multivariate weather variables. The Markov Chain captures the spell statistics while the k-NN bootstrap captures the distributional and lag-dependence statistics of the weather variables. Traditional k-NN generators tend to under-simulate the wet and dry spells that are keys to watershed and agricultural modeling for water planning and management; hence the motivation for this research. We demonstrate the utility of the proposed approach and its improvement over the traditional k-NN approach through an application to daily weather data from Pergamino in the Pampas region of Argentina. We show the applicability of the proposed framework in simulating weather scenarios conditional on the seasonal climate forecast and also at multiple sites in the Pampas region.

  7. Weathering in a Cup.

    ERIC Educational Resources Information Center

    Stadum, Carol J.

    1991-01-01

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

  8. Weathering of Martian Evaporites

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  9. Americans and Their Weather

    NASA Astrophysics Data System (ADS)

    Meyer, William B.

    2000-07-01

    This revealing book synthesizes research from many fields to offer the first complete history of the roles played by weather and climate in American life from colonial times to the present. Author William B. Meyer characterizes weather events as neutral phenomena that are inherently neither hazards nor resources, but can become either depending on the activities with which they interact. Meyer documents the ways in which different kinds of weather throughout history have represented hazards and resources not only for such exposed outdoor pursuits as agriculture, warfare, transportation, construction, and recreation, but for other realms of life ranging from manufacturing to migration to human health. He points out that while the weather and climate by themselves have never determined the course of human events, their significance as been continuously altered for better and for worse by the evolution of American life.

  10. Weather Information Processing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Science Communications International (SCI), formerly General Science Corporation, has developed several commercial products based upon experience acquired as a NASA Contractor. Among them are METPRO, a meteorological data acquisition and processing system, which has been widely used, RISKPRO, an environmental assessment system, and MAPPRO, a geographic information system. METPRO software is used to collect weather data from satellites, ground-based observation systems and radio weather broadcasts to generate weather maps, enabling potential disaster areas to receive advance warning. GSC's initial work for NASA Goddard Space Flight Center resulted in METPAK, a weather satellite data analysis system. METPAK led to the commercial METPRO system. The company also provides data to other government agencies, U.S. embassies and foreign countries.

  11. Blending of satellite and tide gauge sea level observations and its assimilation in a storm surge model of the North Sea and Baltic Sea

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Høyer, Jacob L.; Fu, Weiwei; Donlon, Craig

    2015-09-01

    Coastal storm surge forecasts are typically derived from dedicated hydrodynamic model systems, relying on Numerical Weather Prediction (NWP) inputs. Uncertainty in the NWP wind field affects both the preconditioning and the forecast of sea level. Traditionally, tide gauge data have been used to limit preconditioning errors, providing point information. Here we utilize coastal satellite altimetry sea level observations. Careful processing techniques allow data to be retrieved up to 3 km from the coast, combining 1 Hz and 20 Hz data. The use of satellite altimetry directly is limited to times when the satellite passes over the area of interest. Instead, we use a stationary blending method developed by Madsen et al. (2007) to relate the coastal satellite altimetry with corresponding tide gauge measurements, allowing generation of sea level maps whenever tide gauge data are available. We apply the method in the North Sea and Baltic Sea, including the coastal zone, and test it for operational nowcasting and hindcasting of the sea level. The feasibility to assimilate the blended product into a hydrodynamic model is assessed, using the ensemble optimal interpolation method. A 2 year test simulation shows decreased sea level root mean square error of 7-43% and improved correlation by 1-23% in all modeled areas, when validated against independent tide gauges, indicating the feasibility to limit preconditioning errors for storm surge forecasting, using a relatively cost effective assimilation scheme.

  12. Salt weathering on Mars

    NASA Technical Reports Server (NTRS)

    Malin, M. C.

    1974-01-01

    Mariner 9 photographs of Mars indicate that significant erosion has occurred on that planet. Although several possible erosion mechanisms have been proposed, most terrestrial weathering mechanisms cannot function in the present Martian environment. Salt weathering, believed to be active in the Antarctic dry valleys, is especially suited to Mars, given the presence of salts and small amounts of water. Volcanic salts are probably available, and the association of salts and water is likely from both thermodynamic and geologic considerations.

  13. Effect of Tides On Sea Ice Deformation and Growth Rate

    NASA Astrophysics Data System (ADS)

    Hutchings, J.; Heil, P.; Hibler, W. D.

    Due to high ice strength in present formulations of non-linear plastic sea ice dynamic models, the relatively small tides in the Arctic Basin produces little relative motion. However, recent work with a stand alone sea ice model including a more realistic for- mulation of ice-ocean coupling [Heil & Hibler, accepted] has produced more realistic inertial motion in agreement with observations. With such improved model physics, we expect tidal motion of the ice pack to have a more pronounced effect on simulated periodic lead opening and closing, enhancing winter ice growth rate. To investigate this process, tidal forcing [Kowalik 1998] is included in the momentum balance of a stand alone sea ice model [Heil & Hibler, accepted]. The model includes a modi- fied coulombic rheology, hourly interpolated NCEP reanalysis atmospheric forcing, climatological cloud fraction [Gorshkov,1980] , oceanic currents and heat flux from Polyakov et al. [1998] and inertial embedding as Hibler et al. [1998]. Arctic sea ice is simulated for the period 1948-2000 and compared to a control without tidal forcing. It is investigated how tidal motion and inertial motion interact. As the inertial period is close to the major semi-diurnal tidal period we expect ice deformation in tidally active regions (such as the Barents Sea) to be amplified through inertial resonance. The tidal influence on ice mass balance is estimated. The interannual variability of ice mass is examined to show how tidal influence differs between years of high Arctic Oscillation (AO) index, when ice divergence is increased and trans-polar transport widened, and low AO index, when the Arctic high dominates and convergent motion prevails.

  14. Cockpit weather information system

    NASA Technical Reports Server (NTRS)

    Tu, Jeffrey Chen-Yu (Inventor)

    2000-01-01

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

  15. Short-term variations in mesozooplankton, ichthyoplankton, and nutrients associated with semi-diurnal tides in a patagonian Gulf

    NASA Astrophysics Data System (ADS)

    Castro, L. R.; Cáceres, M. A.; Silva, N.; Muñoz, M. I.; León, R.; Landaeta, M. F.; Soto-Mendoza, S.

    2011-03-01

    The relationships between the distribution of different zooplankton and ichthyoplankton stages and physical and chemical variables were studied using samples and data (CTD profiles, ADCP and current meter measurements, nutrients, mesozooplankton, ichthyoplankton) obtained from different strata during two 24-h cycles at two oceanographic stations in a Chilean Patagonian gulf during the CIMAR 10-Fiordos cruise (November, 2004). A station located at the Chacao Channel was dominated by tidal mixing and small increments in surface stratification during high tides, leading to decreased nutrient availability. This agreed with short periods of increased phytoplankton abundance during slack waters at the end of flood currents. Increases in larval density for all zooplankton and ichthyoplankton taxa corresponded to the flooding phases of the tidal cycle. When the larval density data were fit to a sinusoidal model, the regression coefficients were high, suggesting that tides are important features that modulate short-term variations in plankton abundance. All larvae did not vary synchronously with the tidal phase; rather, time lags were observed among species. The abundances of older individuals of the copepodite Rhincalanus nasutus and all zoea stages of the squat lobster Munida gregaria increased during night flood tides, whereas younger stages increased during daytime flood tides. At a station located at the Queullin Pass, which was dominated by vertical stratification patterns, the variations in peak larval density were better fitted to the semi-diurnal sea level fluctuations. Other evidence indicated internal tides below the pycnocline, which could promote larval transport in deeper layers. In the overall picture that emerges from this study, planktonic organisms from different habitats and phylogenetic origins seem to respond to the local tidal regimes. In some cases, this response might be beneficial, transporting these individuals inshore to areas that are rich in

  16. Successfully Transitioning Science Research to Space Weather Applications

    NASA Technical Reports Server (NTRS)

    Spann, James

    2012-01-01

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

  17. Impact of river-tide dynamics on the residual water level slope and residual sediment transport in the Pearl River channel networks

    NASA Astrophysics Data System (ADS)

    Cai, Huayang; Zhang, Zihao; Yang, Qingshu; Ou, Suying

    2016-04-01

    Large-scale delta systems, such as the Rhine-Meuse delta, the Mississippi River delta, the Mekong delta, the Yangtze delta and the Pearl River delta etc., usually feature a typical channel networks, where individual channels are interrelated through a networks system, resulting in both longitudinal and transverse variations of residual water level slope (averaged over a lunar day) caused by the river-tide interplay. Enhancing our insight of river-tide dynamics in these channel networks has vital importance for the protection and management of estuarine environment since river-tide interplay is closely related to sediment transport, water quality, water utilization and estuarine ecosystem. In this study, we investigate the impact of river-tide dynamics on the temporal-spatial changes of flow and suspended sediment load in terms of residual water level slope and residual sediment transport in the Pearl River channel networks, which is one of the complex channel networks in the world. Making use of a nonstationary harmonic analysis (NS_TIDE), the continuous time series observations of velocity covering a spring-neap cycle in 1999 (representing flood season) and 2001 (representing dry season) collected from around 60 stations in the Pearl River channel networks have been used to extract the temporal-spatial changes in residual velocity and tidal properties (including amplitudes and phases) as a function of variable river flow debouching into the delta. On the basis of harmonic analysis, the tidally averaged friction is decomposed into contributions made by riverine forcing alone, river-tide interaction and tidal asymmetry using Chebyshev polynomials approach. It is shown that river flow enhances friction via river-tide interaction, which increases the residual water level slope that influences the distribution of suspended sediment load in the Pearl River channel networks.

  18. Revisiting the pole tide for and from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Desai, Shailen; Wahr, John; Beckley, Brian

    2015-12-01

    Satellite altimeter sea surface height observations include the geocentric displacements caused by the pole tide, namely the response of the solid Earth and oceans to polar motion. Most users of these data remove these effects using a model that was developed more than 20 years ago. We describe two improvements to the pole tide model for satellite altimeter measurements. Firstly, we recommend an approach that improves the model for the response of the oceans by including the effects of self-gravitation, loading, and mass conservation. Our recommended approach also specifically includes the previously ignored displacement of the solid Earth due to the load of the ocean response, and includes the effects of geocenter motion. Altogether, this improvement amplifies the modeled geocentric pole tide by 15 %, or up to 2 mm of sea surface height displacement. We validate this improvement using two decades of satellite altimeter measurements. Secondly, we recommend that the altimetry pole tide model exclude geocentric sea surface displacements resulting from the long-term drift in polar motion. The response to this particular component of polar motion requires a more rigorous approach than is used by conventional models. We show that erroneously including the response to this component of polar motion in the pole tide model impacts interpretation of regional sea level rise by ± 0.25 mm/year.

  19. Lunar and Solar Torques on the Oceanic Tides

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Bills, Bruce G.; Chao, Benjamin F.

    1998-01-01

    Brosche and Seiler recently suggested that direct lunar and solar tidal torques on the oceanic tides play a significant role in the earth's short-period angular momentum balance ("short-period" here meaning daily and sub-daily). We reexamine that suggestion here, concentrating on axial torques and hence on variations in rotation rate. Only those spherical harmonic components of the ocean tide having the same degree and order as the tidal potential induce nonzero torques. Prograde components (those moving in the same direction as the tide-generating body) produce the familiar secular braking of the earth's rotation. Retrograde components, however, produce rapid variations in UTI at twice the tidal frequency. There also exist interaction torques between tidal constituents, e.g. solar torques on lunar tides. They generate UTI variations at frequencies equal to the sums and differences of the original tidal frequencies. We give estimates of the torques and angular momentum variations for each of the important regimes, secular to quarter-diurnal. For the M(sub 2) potential acting on the M(sub 2) ocean tide, we find an associated angular momentum variation of amplitude 3 x 10(exp 19) N m. This is 5 to 6 orders of magnitude smaller than the angular momentum variations associated with tidal currents. We conclude that these torques do not play a significant role in the short-period angular momentum balance.

  20. On the use of SAR Interferometry for assessing tide gauge stability for long term sea-level estimation

    NASA Astrophysics Data System (ADS)

    Raucoules, Daniel; Cozannet, Gonéri; Woppelmann, Guy

    2015-04-01

    One of the important consequences of climate change is the global sea level rise of 20cm since the end of the 19th century. This process is very likely to continue and accelerate in the future. Future projections of global sea level rise range from about 30cm to 80cm by 2100 with significant regional variability). Local and regional vertical ground motions are one of the important sources of uncertainties to consider in sea level rise impact assessments. However, it is very difficult, if not impossible, to evaluate them without observations due to their complex causes and evolution in space and time. Consequently, a first motivation to accurately characterize vertical ground motions in large coastal cities is to reduce the uncertainties of sea level rise impact assessments. A second challenge motivating a precise characterization of vertical ground motions in coastal cities is to reconcile sea level estimates for the 20th century: over this period, there is a slight disagreement between (1) observations of sea level rise obtained from the available tide gauge data sets, and (2) the sum of contributions from each process causing sea level rise. Accurate knowledge about the ground motions affecting tide gauges is thus highly desirable, especially in regions poorly covered by tide gauges. Indeed, one of the possible explanations of the 20th century sea level budget imbalance is an inappropriate spatial sampling of historical tide gauges along the oceans' coastlines, most being located in Europe and in the United States. In addition, noteworthy is the fact that Tide Gauges with long Time Series are generally located in urbanized areas. Growing of urbanizations in development during the last century can result in local changes of ground surface level (in particular: groundwater extraction produces subsidence phenomena). In this perspective, we propose the use of Differential SAR interferometry techniques for characterizing the ground surface deformation in the

  1. The Early-Warning System for incoming storm surge and tide in the Republic of Mauritius

    NASA Astrophysics Data System (ADS)

    Bogaard, Tom; de Lima Rego, Joao; Vatvani, Deepak; Virasami, Renganaden; Verlaan, Martin

    2016-04-01

    The Republic of Mauritius (ROM) is a group of islands in the South West of the Indian Ocean, consisting of the main islands of Mauritius, Rodrigues and Agalega and the archipelago of Saint Brandon. The ROM is particularly vulnerable to the adverse effects of climate change, especially in the coastal zone, where a convergence of accelerating sea level rise and increasing intensity of tropical cyclones is expected to result in considerable economic loss, humanitarian stresses, and environmental degradation. Storm surges and swell waves are expected to be aggravated through sea level rise and climate change effects on weather patterns. Adaptation to increased vulnerability requires a re-evaluation of existing preparedness measures. The focus of this project is on more effective preparedness and issuing of alerts developing a fully-automated Early-Warning System for incoming storm surge and tide, together with the Mauritius Meteorological Services and the National Disaster Risk Reduction and Management Centre (NDRRMC), such that coastal communities in Mauritius, Rodrigues and Agalega Islands are able to evacuate timely and safely in case of predicted extreme water levels. The Mauritius Early-Warning System for storm surge and tide was implemented using software from Deltares' Open-Source and free software Community. A set of five depth-averaged Delft3D-FLOW hydrodynamic models are run every six-hours with a forecast horizon of three days, simulating water levels along the coast of the three main islands. Two regional models of horizontal resolution 5km force the three detailed models of 500m resolution; all models are forced at the surface by the 0.25° NOAA/GFS meteorological forecasts. In addition, our Wind-Enhancement Scheme is used to blend detailed cyclone track bulletin's info with the larger-scale Numerical Weather Predictions. Measured data is retrieved near real-time from available Automatic Weather Stations. All these workflows are managed by the operational

  2. Tides on Self-gravitating, Compressible Bodies

    NASA Astrophysics Data System (ADS)

    Hurford, T. A.; Greenberg, R.

    2001-11-01

    Most modern derivations of tidal amplitude follow the approach presented by Love [1]. Love's analysis for a homogeneous sphere assumed an incompressible material, which required introduction of a non-rigorously justified pressure term. We have solved the more general case of arbitrary compressibility, which allows for a more straightforward derivation [2,3]. We find the h2 love number of a body of radius R, density ρ , by solving the deformation equation [4], μ ∇ 2 u = ρ ∇U - (λ + μ ) ∇ (∇ ṡ u) where μ is the rigidity of the body and λ the Lamé constant. The potential U is the sum of (a) the tide raising potential, (b) the potential of surface mass shifted above or below the spherical surface, (c) potential due to the internal density changes and (d) the change in potential of each bit of volume due to its displacement u. A self-consistent solution can be obtained with U = \\sum_{q=0}^{\\infty} b_{(2+2q)} r^{(2+2q)} ( {3}/{2} \\cos2 \\theta - {1}/{2} ). In [1] and [3] only the r2 term was considered, which was valid only if compressibility is small or elasticity governs deformation (i.e. ρ g R << (λ + 2 μ )). The solution with only the r2 term reduces to Love's [1] solution in the limit of zero compressibility (λ = ∞ ). However, for rock μ ~ λ [4], in which case h2 is enhanced by ~ 3 %, and solutions for greater compressibility give up to 8 % enhancement of tidal amplitude. If ρ g R is significant, higher order r(2q+2) terms are important and even greater corrections are required to the classical tidal amplitude. [1] Love, A.E.H., New York Dover Publications, 1944 [2] Hurford, T.A. and R. Greenberg, Lunar Plan. Sci. XXXII 1741, 2001 [3] Hurford, T.A. and R. Greenberg, 2001 DDA meeting, Bull. Amer. Astron. Soc. in press [4] Kaula, W.M., John Wiley & Sons, Inc., 1968

  3. Seasonal Variations in Pluto's Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    French, R. G.; Toigo, A. D.; Sicardy, B.; Guzewich, S.; Gierasch, P. J.; Richardson, M. I.

    2013-12-01

    Pluto's tenuous atmosphere exhibits remarkable dynamical activity and seasonal change as a result of the substantial tilt of its rotational axis and its highly elliptical orbit. Early discovery observations by stellar occultation (Elliot et al. 1989 Icarus 77, 148) revealed a relatively symmetrical atmosphere of very low density, with evidence of either a near-surface haze layer or a very cold near-surface layer. Later occultation and spectroscopic measurements showed that the dominant constituent of the atmosphere is nitrogen, with lower abundances of CH4 and other trace amounts of greenhouse gases that control the thermal structure of the middle atmosphere. Over the past two decades, occultations have convincingly demonstrated that the atmospheric pressure on Pluto has increased substantially, perhaps by a factor of 2 to 4, as the planet has moved from equinox towards solstice conditions. These data have also shown an interesting change in dynamical activity in the atmosphere, as revealed by "spikes" in the occultation light curves resulting from refractive focussing by atmospheric waves. In the past two years, a conspicuous asymmetry in wavelike activity has become evident, being much stronger in the winter hemisphere than in the summer. Toigo et al. (2010, Icarus 208, 402) explored the possibility that these waves are caused by solar-induced sublimation and diurnal freezing from N2 frost patches -- weak vertical winds are induced by the rising and sinking gas as it is release from or condenses on the surface. Using a variant of this tidal model, we explore the expected strength and regional characteristics of tides over the course of Pluto's orbit, accounting for changes in insolation and distance from the sun, for a variety of assumed spatial distributions of surface frost. Using a 3-D time-dependent ray-tracing code we compute model light curves for the actual circumstances of several recent occultations, and compare the character of the scintillations in the

  4. DOPPLER WEATHER SYSTEM

    SciTech Connect

    Berlin, Gary J.

    2002-08-05

    The SRS Doppler Weather System consists of a Doppler Server, A Master Server (also known as the Weather Server), several Doppler Slave Servers, and client-side software program called the Doppler Radar Client. This system is used to display near rel-time images taken from the SRS Weather Center's Doppler Radar computer. The Doppler Server is software that resides on the SRS Doppler Computer. It gathers raw data, 24-bit color weather images via screen scraping ever five minutes as requested by the Master Server. The Doppler Server then reduces the 24-bit color images to 8-bit color using a fixed color table for analysis and compression. This preserves the fidelity of the image color and arranges the colors in specific order for display. At the time of color reduction, the white color used for the city names on the background images are remapped to a different index (color) of white that the white on the weather scale. The Weather Server places a time stamp on the image, then compresses the image and passes it to all Doppler Slave servers. Each of the Doppler Slave servers mainitain a circular buffer of the eight most current images representing the last 40 minutes of weather data. As a new image is added, the oldest drops off. The Doppler Radar Client is an optional install program for any site-wide workstation. When a Client session is started, the Client requests Doppler Slave server assignment from the Master Server. Upon its initial request to the Slave Server, the Client obtains all eight current images and maintains its own circular buffer, updating its images every five minutes as the Doppler Slave is updated. Three background reference images are stored as part of the Client. The Client brings up the appropriate background image, decompresses the doppler data, and displays the doppler data on the background image.

  5. DOPPLER WEATHER SYSTEM

    Energy Science and Technology Software Center (ESTSC)

    2002-08-05

    The SRS Doppler Weather System consists of a Doppler Server, A Master Server (also known as the Weather Server), several Doppler Slave Servers, and client-side software program called the Doppler Radar Client. This system is used to display near rel-time images taken from the SRS Weather Center's Doppler Radar computer. The Doppler Server is software that resides on the SRS Doppler Computer. It gathers raw data, 24-bit color weather images via screen scraping ever fivemore » minutes as requested by the Master Server. The Doppler Server then reduces the 24-bit color images to 8-bit color using a fixed color table for analysis and compression. This preserves the fidelity of the image color and arranges the colors in specific order for display. At the time of color reduction, the white color used for the city names on the background images are remapped to a different index (color) of white that the white on the weather scale. The Weather Server places a time stamp on the image, then compresses the image and passes it to all Doppler Slave servers. Each of the Doppler Slave servers mainitain a circular buffer of the eight most current images representing the last 40 minutes of weather data. As a new image is added, the oldest drops off. The Doppler Radar Client is an optional install program for any site-wide workstation. When a Client session is started, the Client requests Doppler Slave server assignment from the Master Server. Upon its initial request to the Slave Server, the Client obtains all eight current images and maintains its own circular buffer, updating its images every five minutes as the Doppler Slave is updated. Three background reference images are stored as part of the Client. The Client brings up the appropriate background image, decompresses the doppler data, and displays the doppler data on the background image.« less

  6. Influence of fortnightly earth tides at Kilauea Volcano, Hawaii.

    USGS Publications Warehouse

    Dzurisin, D.

    1980-01-01

    Analysis of 52 historic eruptions confirms the premise that fortnightly earth tides play a significant role in triggering activity at Kilauea Volcano, Hawaii. Since January 1832, nearly twice as many eruptions have occurred nearer fortnightly tidal maximum than tidal minimum (34 vs. 18). A straightforward significance test indicates that the likelihood of a fortnightly tidal influence on Kilauea eruptions is roughly 90%. This is not the case for Mauna Loa Volcano, where 37 historic eruptions have been distributed randomly with respect to the fortnightly tide. At Kilauea, stresses induced by fortnightly earth tides presumably act in concert with volcanic and tectonic stresses to trigger shallow magma movements along preexisting zones of weakness. Differences in structure or internal plumbing may limit the effectiveness of this mechanism at Mauna Loa. Tidal effects seem to be less marked at shields than at some island-arc volcanoes, possibly because higher average volcanic stress rates in Hawaii more often override the effects of tidal stresses.-Author

  7. Influence of fortnightly earth tides at Kilauea Volcano, Hawaii

    SciTech Connect

    Dzurisin, D.

    1980-11-01

    Analysis of 52 historic eruptions confirms the premise that fortnightly earth tides play a significant role in triggering activity at Kilauea Volcano, Hawaii. Since January 1832, nearly twice as many eruptions have occurred nearer fortnightly tidal maximum than tidal minimum (34 vs 18). A straightforward significance test indicates that the likelihood of a fortnightly tidal influence on Kilauea eruptions is roughly 90%. This is not the case for Mauna Loa Volcano, where 37 historic eruptions have been distributed randomly with respect to the fortnightly tide. At Kilauea, stresses induced by fortnightly earth tides presumably act in concert with volcanic and tectonic stresses to trigger shallow magma movements along preexisting zones of weakness. Differences in structure or internal plumbing may limit the effectiveness of this mechanism at Mauna Loa. Tidal effects seem to be less marked at shields than at some island-arc volcanoes, possibly because higher average volcanic stress rates in Hawaii more often override the effects of tidal stresses.

  8. Global ocean tides. Part III. The semidiurnal principal solar tide (S2), atlas of tidal charts and maps. Final report

    SciTech Connect

    Schwiderski, E.W.

    1981-03-15

    In Part I of this report (AD-A060 913), a unique hydrodynamical interpolation technique was introduced, extensively tested, and evaluated in order to compute partial global ocean tides in great detail and with a high degree of accuracy. This novel method has been applied to construct the semidiurnal principal solar (S2) ocean tide with a relative accuracy of better than 5 cm anywhere in the open oceans. The resulting tidal amplitudes and phases are tabulated on a 1 deg x 1 deg grid system in an atlas of 42 deg x 71 deg overlapping charts covering the whole oceanic globe. A corresponding atlas of global corange and cotidal maps is included to provide the reader with a quick general overview of the major tidal phenomena. The specifying hydrodynamical parameters of the model are listed along with quoted sources of empirical tide data, and significant tidal features are explained and discussed. The S2 ocean tide is found to resemble closely the corresponding lunar M2 tide presented in Part II of this report (AD-A084 694).

  9. The Anomalously High Pole Tide in the North and Baltic Seas Estimated by the PSMSL Tide Gauge Data

    NASA Astrophysics Data System (ADS)

    Medvedev, Igor; Rabinovich, Alexander; Kulikov, Evgueni

    2014-05-01

    Pole tide driven by the Chandler wobble, has the period of about 14 months and typical amplitudes in the World Ocean of ~ 0.5 cm. However, in the North and Baltic Seas they are anomalously high. To examine this effect we used long monthly sea level records from 80 stations with the length up to 212 years. High-resolution spectra revealed a cluster of neighboring peaks with periods from 410 to 440 days. The results of spectral analysis were applied to estimate the integral amplitudes of pole tides from all available tide gauges along the coast of seas. The height of the pole tide was found to gradually increase from the entrance of the Baltic Sea (Danish Straits) to the northeast end of the Baltic Sea. The largest amplitudes - up to 4.5-7 cm - were observed in the heads of the Gulf of Finland and the Gulf of Bothnia. Significant temporal fluctuations in amplitudes and periods of the pole tide were observed during XIX and XX centuries.

  10. Barotropic tides in the global oceans from a nonlinear tidal model assimilating altimetric tides. 2. Altimetric and geophysical implications

    NASA Astrophysics Data System (ADS)

    Kantha, Lakshmi H.; Tierney, Craig; Lopez, Joseph W.; Desai, Shailen D.; Parke, Michael E.; Drexler, Laura

    1995-12-01

    In this second part, we explore the implications of the tides derived from the high-resolution, data-assimilative, nonlinear barotropic global ocean tidal model described by Kantha (this issue) in altimetric analysis and geophysical applications. It is shown that when applied to the task of removing tidal sea surface height from TOPEX altimetric records, the model performance is comparable to other global tidal models in the open ocean as measured by the reduction in crossover variances. The performance is slightly better than that of the only other high-resolution global tidal model from Grenoble (Le Provost et al., 1994). The results are however mixed in regions shallower than 1000 m and in semienclosed seas such as the Bering Sea, with the model performance slightly worse overall than the Grenoble model. Computations of total power input (and hence total tidal dissipation rate) are shown to be in excellent agreement with recent analyses of TOPEX data and geophysical observations. In addition, distributions of the tidal power input, tidal dissipation, and the power fluxes in the global oceans are shown for the two primary constituents, M2 and K1. Load tides in solid Earth due to ocean tidal loading fluctuations are also computed for the major semidiurnal and diurnal constituents. The load tides are shown to be large in the shallow seas adjacent to the coasts with high tides such as the Patagonian shelf, because of the higher resolution of this global tide model. This has potential implications in geophysical applications.

  11. Remote Sensing Monitoring of Tide Propagation Through Coastal Wetlands

    NASA Astrophysics Data System (ADS)

    Wdowinski, S.; Hong, S.; Mulcan, A.; Brisco, B.

    2013-05-01

    Coastal wetlands including mangrove forests and saltwater marshes are considered among the most valuable ecosystems on earth, yet their existence is presently being threatened by climate change (sea-level rise) and human interference (e.g. infrastructure development). These fragile ecosystems depend on a continuous water and nutrient replenishment by ocean tidal flow. While ocean tides are well known and forecasted, tidal flow movements through coastal wetlands are poorly known due to the fact that vegetation resists the flow and delays both inland and seaward flow at rising and subsiding tide conditions, respectively. Thus far, most observations on tide propagation through coastal wetlands have been obtained from stage (water level) measurements within the vegetated tidal zone. These stage measurements possess high temporal resolution observations, but acquired at a limited number of measurement points. Wetland InSAR (Interferometric Synthetic Aperture Radar) observations provide a new complementary source of information for detecting tidal flow in coastal wetlands, by supplying high spatial resolution maps of water level changes between two SAR acquisition times. In this study, we use InSAR observations to detect surface water level changes in response to ocean tide propagation through the coastal Everglades' mangrove forests. Interferometric processing of the data show that the highest rate of water level changes occurs near channels, as the Shark Valley River (Fig 1., center of image). These high water level gradients reflect rapid horizontal flow into and from the channel during low and high tide conditions, respectively. The high spatial resolution wetland InSAR observations provide important constraints for detailed coastal wetland flow models. RADARSAT-2 interferogram of western south Florida showing tide-induced water level changes along the transition between the saltwater mangrove marsh in the southwest and freshwater swamp in the northeast.

  12. New weather index

    NASA Astrophysics Data System (ADS)

    Scientists at the National Oceanic and Atmospheric Administration (NOAA) and the University of Delaware have refined the wind-chill factor, a common measurement of weather discomfort, into a new misery register called the weather stress index. In addition to the mix of temperature and wind speed data used to calculate wind chill, the recipe for the index adds two new ingredients—humidity and a dash of benchmark statistics—to estimate human reaction to weather conditions. NOAA says that the weather stress index estimates human reaction to weather conditions and that the reaction depends on variations from the ‘normal’ conditions in the locality involved.Discomfort criteria for New Orleans, La., and Bismarck, N.D., for example, differ drastically. According to NOAA, when it's the middle of winter and it's -10°C with a relative humidity of 80% and 24 km/h winds, persons in New Orleans would be highly stressed while those in Bismarck wouldn't bat an eye.

  13. [Weather, climate and health].

    PubMed

    Banić, M; Plesko, N; Plesko, S

    1999-01-01

    The notion of complex influence of atmospheric conditions on modem human population, especially the relationship between weather, climate and human healths, has actuated the World Meteorological Organisation to commemorate the coming into force, on March 23, 1950, of the Convention of WMO and this year to celebrate this day by focusing on theme of current interest--"Weather, climate and health". In the light of this, the authors of this paper reveal the results of recent studies dealing with influence of sudden and short-term changes in weather and climate on human health, and future expected climate changes due to "greenhouse" effect, increase in global temperature and tropospheric ozone depletion, as well. Special attention is given to climate shifts due to ENSO (El Niño/Southern Oscillation) phenomenon because of its great impact on human society and epidemics of certain infectious diseases. The results of biometeorological studies dealing with complex influence of daily weather changes on incidence of certain diseases in Croatia have also been presented. In addition, the authors have stated their own view and opinion in regard to future biometeorlogical studies in Croatia in order to achieve better understanding of influence of climate and weather changes on human health, and help prevention of mortality and morbidity related to chronic noninfectious diseases. PMID:19658377

  14. Linking Europa's plume activity to tides, tectonics, and liquid water

    NASA Astrophysics Data System (ADS)

    Rhoden, Alyssa Rose; Hurford, Terry A.; Roth, Lorenz; Retherford, Kurt

    2015-06-01

    Much of the geologic activity preserved on Europa's icy surface has been attributed to tidal deformation, mainly due to Europa's eccentric orbit. Although the surface is geologically young (30-80 Myr), there is little information as to whether tidally-driven surface processes are ongoing. However, a recent detection of water vapor near Europa's south pole suggests that it may be geologically active. Initial observations indicated that Europa's plume eruptions are time-variable and may be linked to its tidal cycle. Saturn's moon, Enceladus, which shares many similar traits with Europa, displays tidally-modulated plume eruptions, which bolstered this interpretation. However, additional observations of Europa at the same time in its orbit failed to yield a plume detection, casting doubt on the tidal control hypothesis. The purpose of this study is to analyze the timing of plume eruptions within the context of Europa's tidal cycle to determine whether such a link exists and examine the inferred similarities and differences between plume activity on Europa and Enceladus. To do this, we determine the locations and orientations of hypothetical tidally-driven fractures that best match the temporal variability of the plumes observed at Europa. Specifically, we identify model faults that are in tension at the time in Europa's orbit when a plume was detected and in compression at times when the plume was not detected. We find that tidal stress driven solely by eccentricity is incompatible with the observations unless additional mechanisms are controlling the eruption timing or restricting the longevity of the plumes. The addition of obliquity tides, and corresponding precession of the spin pole, can generate a number of model faults that are consistent with the pattern of plume detections. The locations and orientations of these hypothetical source fractures are robust across a broad range of precession rates and spin pole directions. Analysis of the stress variations across

  15. Tide Corrections for Coastal Altimetry: Status and Prospects

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Egbert, Gary D.

    2008-01-01

    Knowledge of global oceanic tides has markedly advanced over the last two decades, in no small part because of the near-global measurements provided by satellite altimeters, and especially the long and precise Topex/Poseidon time series e.g. [2]. Satellite altimetry in turn places very severe demands on the accuracy of tidal models. The reason is clear: tides are by far the largest contributor to the variance of sea-surface elevation, so any study of non-tidal ocean signals requires removal of this dominant tidal component. Efforts toward improving models for altimetric tide corrections have understandably focused on deep-water, open-ocean regions. These efforts have produced models thought to be generally accurate to about 2 cm rms. Corresponding tide predictions in shelf and near-coastal regions, however, are far less accurate. This paper discusses the status of our current abilities to provide near-global tidal predictions in shelf and near-coastal waters, highlights some of the difficulties that must be overcome, and attempts to divine a path toward some degree of progress. There are, of course, many groups worldwide who model tides over fairly localized shallow-water regions, and such work is extremely valuable for any altimeter study limited to those regions, but this paper considers the more global models necessary for the general user. There have indeed been efforts to patch local and global models together, but such work is difficult to maintain over many updates and can often encounter problems of proprietary or political nature. Such a path, however, might yet prove the most fruitful, and there are now new plans afoot to try again. As is well known, tides in shallow waters tend to be large, possibly nonlinear, and high wavenumber. The short spatial scales mean that current mapping capabilities with (multiple) nadir-oriented altimeters often yield inadequate coverage. This necessitates added reliance on numerical hydrodynamic models and data assimilation

  16. The Role of Tides in Known Multi-Planet Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The first known extrasolar planet system, upsilon Andromedae, was discovered in 1999. The number of stars known to possess more than one planet has been growing rapidly since then. The dynamical interactions among such planets can be quite strong. These interactions can excite the orbital eccentricities of planets, even planets orbiting very close to their stars. Stellar tides can damp the eccentricities of such close-in planets, removing dynamical energy from the system and ultimately affecting the motions of all of the planets. These and other effects of tides in extrasolar multi-planet systems will be discussed.

  17. Present weather and climate: evolving conditions

    USGS Publications Warehouse

    Hoerling, Martin P; Dettinger, Michael; Wolter, Klaus; Lukas, Jeff; Eischeid, Jon K.; Nemani, Rama; Liebmann, Brant; Kunkel, Kenneth E.

    2013-01-01

    This chapter assesses weather and climate variability and trends in the Southwest, using observed climate and paleoclimate records. It analyzes the last 100 years of climate variability in comparison to the last 1,000 years, and links the important features of evolving climate conditions to river flow variability in four of the region’s major drainage basins. The chapter closes with an assessment of the monitoring and scientific research needed to increase confidence in understanding when climate episodes, events, and phenomena are attributable to human-caused climate change.

  18. Space Weather in Magnetic Observatory Noise

    NASA Astrophysics Data System (ADS)

    Gilder, S. A.; Truong, F.

    2012-12-01

    Space weather impacts human activity by degrading satellite operation or disrupting electrical power grids. By exploiting small differences in the time stamp between magnetometer pairs to facilitate data filtering, we find that ground-based magnetic observatories are well suited to measure space weather phenomena, and in particular, high frequency fluctuations known as pulsations. Several of the world's consortium of INTERMAGNET observatories are used in the analyses. They show that pulsation amplitudes attain a maximum near local noon over diurnal periods. Long-term trends in pulsation amplitude correlate well with the solar cycle, with the greatest effect occurring during the waning part of the cycle when the derivative of the number of sunspots attains a maximum rate of decrease. Seasonal variability and total amplitude of the diurnal expression of pulsations depends on latitude. Our study highlights the utility of ground-based observatories to understand solar phenomena and suggests how INTERMAGNET data and protocol could be better tuned to monitor space weather.

  19. Spectrum of mesoscale sea level oscillations in the northern Black Sea: Tides, seiches, and inertial oscillations

    NASA Astrophysics Data System (ADS)

    Medvedev, I. P.; Kulikov, E. A.

    2016-01-01

    Long-term data from 23 tide gauges were used to analyze the spectrum of mesoscale sea level variability of the Black Sea. The tides have sharp spectral peaks, and they are detected at diurnal and semidiurnal frequencies for all stations. A local wide spectral peak associated with inertial oscillations is located between the diurnal and semidiurnal tidal peaks. This peak is well known in the spectra of the current velocity variations of the Black Sea, but in the sea level spectrum it has been identified for the first time. At frequencies of >3 cpd, sea level spectra of the Black Sea have (1) wide maxima in the continuous spectrum, which correspond to the main eigenmodes of the sea with periods of 5.6, 4.8, 4.1, and 3.1 h, and (2) sharp peaks of radiational harmonics S3, S4, S5, and S6. The periods of seiches calculated in this study are close to the periods of eigenmodes of the Black Sea, obtained by the numerical modeling of other authors. The main factors influencing the formation of radiational tides in the Black Sea are presumably breezes and runoff from large rivers. The significant predominance of a harmonic with frequency of 5 cpd (S5) over other radiational harmonics is caused by the influence of an eigenmode, with a frequency of about 5 cpd. The proximity of the periods of these oscillations leads to resonant amplification and to a corresponding increase in amplitude of the radiational harmonic S5.

  20. New weather radar coming

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    What would you call the next generation of radar for severe weather prediction? NEXRAD, of course. A prototype for the new system was recently completed in Norman, Okla., and by the early 1990s up to 195 stations around the United States will be tracking dangerous weather and sending faster, more accurate, and more detailed warnings to the public.NEXRAD is being built for the Departments of Commerce, Transportation, and Defense by the Unisys Corporation under a $450 million contract signed in December 1987. Th e system will be used by the National Weather Service, the Federal Aviation Administration (FAA), and the U.S. Air Force and Navy. The NEXRAD radar tower in Norman is expected to be operational in October.